1 Ag84Ah

COTTON

GINNERS

HANDBOOK

AGRICULTURE HANDBOOK NO. 503

Agricultural Research Service

United States Department of Agriculture

COTTON GINNERS HANDBOOK

Agriculture Handbook No. 503

Agricultural Research Service

UNITED STATES DEPARTMENT OF AGRICULTURE

Washington, D.C. Issued July 1977

For sale by the Superintendent of Documents, U.S. Government Printing Office

Washington, D.C. 20402 -Price $2.50

25% discount allowed on orders of 100 or more to one address

Stock No. 001-000-03678-5
CONTRIBUTORS

D. M. Alberson, former agricultural engineer, Agricultural Research Service.

W. Stanley Anthony, agricultural engineer, U.S. Cotton Ginning Research Laboratory,

Agricultural Research Service, P.O. Box 256, Stoneville, Miss. 38776.

R. V. Baker, agricultural engineer. South Plains Cotton Ginning Research Laboratory,

Agricultural Research Service, Route 3, Box 215, Lubbock, Tex. 79401.

R. F. Colwick, agricultural engineer. Cotton Production Research Unit, Agricultural

Research Service, P.O. Box 5465, Mississippi State, Miss. 39762.

G. N. Franks, former agricultural engineer. Agricultural Research Service.

W. E. Garner, agricultural engineer, U.S. Cotton Ginning Research Laboratory, Agricultural Research Service, P.O. Box 256, Stoneville, Miss. 38776.

Anselm C. Griffin, Jr., physicist, U.S. Cotton Ginning Research Laboratory, Agricultural Research Service, P.O. Box 256, Stoneville, Miss. 38776.

L W. Kirk, agricultural engineer. Southwestern Cotton Ginning Research Laboratory,

Agricultural Research Service, P.O. Box 578, Mesilla Park, N. Mex. 88047.

J. W. Laird, agricultural engineer. South Plains Cotton Ginning Research Laboratory,

Agricultural Research Service, Route 3, Box 215, Lubbock, Tex. 79401.

Oliver L. McCaskill, agricultural engineer, U.S. Cotton Ginning Research Laboratory,

Agricultural Research Service, P.O. Box 256, Stoneville, Miss. 38776.

Gino J. Mangialardi, Jr., agricultural engineer, U.S. Cotton Ginning Research Laboratory, Agricultural Research Service, P.O. Box 256, Stoneville, Miss. 38776.

Vernon P. Moore, former cotton technologist. Agricultural Research Service.

J. H. Tony Price, executive vice president, Texas Cotton Ginners' Association, P.O. Box

44072, Dallas, Tex. 75234.

S. T. Rayburn, Jr., agricultural engineer, U.S. Cotton Ginning Research Laboratory,

Agricultural Research Service, P.O. Box 256, Stoneville, Miss. 38776.

C. S. Shaw, former cotton technologist. Agricultural Research Service.

L. L. Smith, former agricultural engineer. Agricultural Research Service.

V. L. Stedronsky, former agricultural engineer (deceased). Agricultural Research

Service.

W. E. Taylor, agricultural engineer, Agricultural Engineering Department, Oklahoma

State University, Stillwater, Okla. 74074.

J. E. Vaughn, manager. Fire Prevention and Engineering Bureau of Texas, 1320

Mercantile Securities Building, Dallas, Tex. 75201.

R. A. Wesley, agricultural engineer, U.S. Cotton Ginning Research Laboratory, Agricultural Research Service, P.O. Box 256, Stoneville, Miss. 38776.

T. E. Wright, agricultural engineer. Southwestern Cotton Ginning Research Laboratory,

Agricultural Research Service, P.O. Box 578, Mesilla Park, N. Mex. 88047.

Grateful acknowledgment is made for illustrations as follows: Bush-Hog/Continental Gin, Prattville, Ala., figs. 3-11, 3-12, 3-13, 3-14, 3-16, 3-20, 3-23, 3-28, 3-30,

3-41, 3-42, 3-44, 3-46, 3-49, 4-1, and 4-5; Cen-Tennial Cotton Gin Co., Columbus,

Ga., figs. 3-5 and 3-6; Hardwicke-Etter Co., Sherman, Tex., figs. 3-18, 3-25, 3-27,

3-31, 3-45, and 4-3; International Harvester Co., Chicago, 111., fig. 5-1; KimbellBishard, Lubbock, Tex., fig. 4-6; Lummus Industries, Inc., Columbus, Ga., figs. 3-15,

3-17, 3-19, 3-22, 3-24, 3-26, 3-29, 3-32, 3-34, 3-40, 3-43, 3-50, and 4-4; MurrayPiratininga Machinery Corp. (Murray-Carver), Dallas, Tex., figs. 3-9, 3-10, 3-33,

3-35, and 4-2.

This publication supersedes Agriculture Handbook No. 260, ''Handbook for Cotton

Ginners," February 1964.

Trade names are used in this publication solely for the purpose of providing

specific information. Mention of a trade name does not constitute a guarantee or

warranty of the product by the U.S. Department of Agriculture or an endorsement

by the Department over other products not mentioned.
CONTENTS

Page

Contributors ü

SECTION 1.—DEVELOPMENT OF THE SAW GIN, by Vernon P.

Moore 1

SECTION 2.—GROWING, HARVESTING, AND STORAGE 5

Growing and Harvesting for Quality Ginning, by R. F. Colwick 5

Seed-Cotton Storage, by Anselm C. Griffin, Jr 6

SECTION 3.—THE GINNING PROCESS 11

Green-Boll Traps, by J. W. Laird and W. E. Taylor 11

Cotton Moisture Control, by Anselm C. Griffin, Jr 13

Cleaning and Extracting, by W. E. Garner and R. V. Baker 18

Gin Stands, by T. E. Wright and Vernon P. Moore 29

Lint Cleaning, by Gino J. Mangialardi, Jr 35

Packaging of Lint Cotton, by Oliver L. McCaskill and W. Stanley

Anthony 43

SECTION 4.—MATERIALS HANDLING 53

Separators and Droppers, by T. E. Wright 53

Fans and Piping, by Oliver L. McCaskill, R. V. Baker, and V. L.

Stedronsky 57

Mechanical Conveyors, by D. M. Alberson 67

Cottonseed Handling, by S. T. Rayburn, Jr., G. N. Franks, and C. S.

Shaw 69

Cottonseed Aeration and Storage, by L. L. Smith and S. T. Rayburn, Jr 72

Collection and Disposal of Gin Waste, by Oliver L. McCaskill, R. V.

Baker, and R. A. Wesley 80

Pink Bollworm Control in Gin Operations, by I. W. Kirk 92

SECTION 5.—POWER: MOTORS AND ENGINES, by W. E.

Garner 97

SECTION 6.—GINNING RECOMMENDATIONS 101

Gins To Handle Specific Types of Cotton, by W. E. Garner and

R. V. Baker 101

Effects of Gin Machinery on Cotton Quality, by Anselm C. Griffin, Jr 102

SECTION 7.—MISCELLANEOUS CONSIDERATIONS 105

Fuel Value of Gin Wastes, by Anselm C. Griffin, Jr 105

Fire Prevention Considerations, by J. E. Vaughn 106

Gin Safety, by J. H. Tony Price 108

SECTION 1. —DEVELOPMENT OF THE SAW GIN

By VERNON P. MOORE

The invention of the cotton gin triggered the

equivalent of an industrial revolution in the

South and made possible the development of

a major export commodity, which was badly

needed by a growing nation. Mass production

of the crop coupled with ever-increasing labor

costs made it necessary to develop mechanical

handling methods, means for removing moisture and foreign matter from fiber, and faster

processing to cope with changing harvesting

methods and volume of cotton produced.

To trace in detail the development of the saw

gin would require much more than the allotted

space. Suffice it to say that the economic development of the cotton States, a large export

market, and the basis of mass production came

about in no small measure because of the efforts

of a school teacher from Massachusetts. Eli

Whitney's (1765-1825) invention provided the

means of filling the needs of a young and

struggling America for fiber and firearms. His

development of mass-production methods for

the manufacture of firearms from standard

parts helped build and defend this country.

His development of the cotton gin opened up

new industry and revolutionized agriculture in

the South. The soldier on guard at a lonely outpost and the pioneer that followed him owed

the shirts on their backs and the rifles in their

hands to this man who taught school on Mrs.

Nathanael Greene's plantation at Mulberry

Grove, about 12 miles from Savannah, Ga.

The climate of the South was favorable for

growing cotton, but production had been limited

to the amount that could be removed from the

seeds by hand. The invention of the gin broke

that bottleneck: the cotton gin Whitney patented in 1794 (fig. 1-1) made it possible to

separate lint from seed about 100 times as fast

as it could be done by hand. His gin removed

the fibers from the seed by means of spikes

on a cylinder. The spikes pulled lint through

slots that were too narrow for the seeds to pass.

A revolving brush removed the lint from the

spikes. Many refinements have been made, but

the basic principle remains unchanged (fig.

1-2).

The first major improvement was made by

Hodgen Holmes, a mechanic working with

Whitney. He used saws rather than spikes to

remove the fibers from the seed and opened the

bottom of the roll box to make gin operation

continuous rather than the batch process it was

with Whitney's device. His patent was issued

in 1796. Changing ginning from an intermittent

to a continuous operation made it more efficient

and also increased capacity. Using circular

saws and flat ribs instead of the spiked cylinder

made it possible for farm mechanics and blackPN-5230

FIGURE l-l.—Model, built in the shops of the U.S. Cotton Ginning Research Laboratory, Stoneville, Miss.,

of Eli Whitney's gin.
PN-B2S1

FIGURE 1-2.—Model gin with modern saws and ribs.

smiths to produce a gin for use on a plantation.

One of the earliest gins was on Bryan's Creek

near Oxford, Ga. It was powered by a water

wheel.

As production increased, the gin became a

symbol of the prosperous plantation owner.

Expanding acreage brought with it a new problem: workers could hardly pick the cotton from

the stalk as carefully as before, and, in their

haste, they picked more trash with the cotton.

The trash made the fiber less desirable to mills

because it did not spin as well and there was

more waste. For a while, the trash was picked

from the cotton by hand, but for the laborer

and his family sitting by the fireside at night,

this was a weary task after they had worked

in the fields all day.

It is quite probable that there were many

attempts to clean cotton mechanically. The first

evidence available to the U.S. Cotton Ginning

Research Laboratory is a wooden cleaner constructed by a gin hand in 1840 at the Blakely

Plantation Gin a few miles north of Vicksburg,

Miss. (fig. 1-3). It was driven by a steam

engine, which is on display at the Blakely

Plantation.

In 1884, systems to handle bulk seed cotton

began to come on the market, making it possible

to feed several gin stands simultaneously. The

first system conveyed seed cotton by pneumatic

suction from wagons to a screen box that acted

as a separator to feed a distributor. The development of feeders began in 1794; however,

hand feeding was prevalent until a successful

L I

^'iiS^-'^'^

PN-B282

FIGURE 1-3.—Wooden seed-cotton cleaner built by a

slave for the Blakely Plantation Gin north of

Vicksburg, Miss.

mechanical feeder was developed by Alex Jones

in 1834. The conveying system coupled with

the feeder took much of the hand labor from

ginning, and systems powered primarily by

mules or water wheels rapidly developed.

Packaging the lint was a major problem at

early gins. The usual practice was to package

it in sacks hung from frames built around holes

in the floor. The cotton was stuffed into the

sack through the hole and packed down by

workers' feet. Apparently the first cotton screw

press was tried about 1799.

Refinements in the gin stand and in cleaning,

conveying, and packaging equipment in the

1800's and early 1900's met the needs of plantation owners very well. Cotton could be harvested in clear weather and ginned in rainy

weather. As the cost of gins continued to increase, however, because of the additional

cleaning equipment needed to process the progressively trashier harvested cotton, commercial installations began to replace plantation

gins. The more efficient machinery became in
removing trash and moisture, the rougher the

harvesting methods became, until a point was

reached where the lower grades were costing

producers millions of dollars each year. The

damp, trashy cotton could neither be cleaned

nor ginned successfully. It roped, twisted, and

tangled in the machinery. It would not spin

well or make high-grade yarn, resulting in fiber

price discounts of as much as 20 percent.

In 1926, farmers of the Mississippi Valley,

through Congressmen J. P. Buchanan of Texas

and W. M. Whittington of Mississippi, asked

the Department of Agriculture to develop a

method for drying cotton to facilitate cleaning

and reduce the losses attributable to rough

preparation. Charles A. Bennett, who was stationed at Tallulah, La., developed and patented

a drier that was put into operation in gins in

the fall of 1929. The U.S. Cotton Ginning Research Laboratory, having facilities for fiber

analysis also, was built at Stoneville, Miss., in

1931. Engineering research was under Bennett's direction; fiber analysis and quality

evaluation were directed by Francis L. Gerdes.

These two built a research program that continues today. Facilities for ginning investigations were later established at Mesilla Park,

N. Mex.; Clemson, S.C; and Lubbock, Tex.

Many public service patents, most covering

basic items of equipment, have been granted,

and more have been applied for covering developments by these laboratories. All manufacturers have access to the patents, some of which

represent major advances. The seed-cotton

drier, the cotton-lint cleaner, and the stick and

green-leaf machine rival the invention of the

gin itself in their importance to the cotton

world, playing a major role in making the use

of mechanical harvesting economically feasible.

Furthermore, the drier made possible the more

efficient use of gin machinery. Cottons that

previously could not be ginned at all can now

be processed satisfactorily, since dry cotton

releases trash more readily and can be processed through more cleaning equipment without damage to fibers, if they are not overdried.

The mechanical harvesting methods that

came into extensive use following World War II

made it possible to harvest cotton rapidly, and

as a result, the ginning season gradually shrank

from 6 months to 6 or 8 weeks. The gin became

the bottleneck, and the pressure was on to

develop higher capacity machines. Developments at Stoneville resulted in a gin stand that

would remove the fiber from the seed about

four times as fast as gins then in commercial

production. Manufacturers quickly adopted the

Stoneville design or developed their own

versions, as well as increasing the capacity of

other components in the plant. The accelerated

ginning rate made necessary major changes in

the handling system. Even by speeding up

press-ram travel and other innovations, it was

virtually impossible for a press crew to tie out

bales as fast as they could be ginned. The industry took the lead in solving this problem,

through the Packaging Committee, formed in

1968, of the National Cotton Council. The efforts of this committee, working with various

segments of the industry, the ginning laboratories, and the gin manufacturers, have produced numerous improvements. They include

net-weight trading, which cleared the way for

automatic strapping; plastic shrink-wrap bale

covering; and other innovations that have substantially aided in gearing the gin to the

harvesting rate.

These developments, however, have not fully

solved the ginning problem for mechanically

harvested cotton. Seed cotton must be dried,

cleaned, and ginned at a rate as high as 18

tons an hour. The lint must be packaged in

500-pound bales at 6 tons or so an hour for the

average high-capacity plant. The handling of

this volume of material without fiber damage

requires automatic drying systems that avoid

overdrying the fiber, new types of seed-cotton

cleaners for efficient trash removal, more efficient lint cleaners, better trash disposal systems, and automatic controls for the various

processes to reduce labor costs. The ginner

must process cotton rapidly for his customer,

the farmer, and at the same time preserve

spinning quality for the mill. Cotton mills, like

farmers, are demanding more from cotton than

ever before in an effort to reduce costs. The gin

today cannot perform miracles, although it may

seem to do so when it is compared to those

built by Eli Whitney. The saw gin cannot improve quality; it can only preserve it. Ginning

research is aimed at preserving the quality of

the lint to meet the exacting requirements of

the farmers' customer, the textile industry—

and that is a main emphasis of this publication.

SECTION 2.-GROWING, HARVESTING, AND STORAGE

Growing and Harvesting for

Quality Ginning

By R. F. COLWICK

Cultural practices that may influence cottonharvesting operations vary widely across the

Cotton Belt, largely because of differences in

soil and weather conditions. Local agricultural

experiment stations should be consulted for

recommendations on such aspects of production

as variety selection, fertilization rates, irrigation practices, weed control methods, and insect

control.

Selecting the field and preparing the land

are important steps in preparing for harvest.

The land should be well drained and the fields

laid out for effective use of machines. Residue

from previous crops should be shredded sufficiently in the fall to discourage insect hibernation and to promote decay during the winter.

Turn rows should be smoothed out at least 25

feet wide to allow the harvester to enter the

rows in proper alinement and at normal

operating speed.

Uniform stands of 30,000 to 50,000 plants

per acre encourage the growth of the plant

type best suited for mechanical harvesting. Because grass is difficult to remove in the gin,

the fields should be kept clean. The shape or

profile of the rows has a bearing on the amount

of trash in machine-harvested cotton. The last

cultivation should leave the row elevated 2 or

3 inches, with the slope away from the base

of the plants on each side. Large, late-fruiting

plants should be avoided, since they are subject

to lodging, boll rot, and difficulty in defoliation.

Removing the leaves from the cotton plant

with chemicals helps minimize green-leaf trash

in mechanically harvested cotton and promotes

faster drying of dew on the lint. Defoliants

make plants shed their leaves, and desiccants

kill plant tissue. In most areas where the picker

harvester is used, defoliants should be applied

when at least 60 percent of the bolls are open.

All bolls should be mature and about 90 percent

should be open before desiccants are applied.

Moisture in machine-harvested cotton can be

kept at a minimum by proper timing with

respect to weather. The moisture in seed cotton

varies directly with the relative humidity of

the air around the plant. As a general rule,

cotton should not be harvested for storage until

it has dried to a moisture content of 10 percent

or less on the plant. In some areas, this does

not occur until 9 or 10 a.m. on a clear day

(Parker and Wooten 1964). If cotton is picked

before it has dried to a moisture level safe for

storage, it should be ginned immediately. This

is especially important if seed is to be saved

for planting. If the seed moisture is above 12

percent, seed deterioration is likely to occur in

storage.

The amount of trash or leaf harvested by

the machine has a direct bearing on the total

moisture content. Trash, whether green or dry,

usually has a higher moisture content than

the seed cotton itself. As soon as the trash and

seed cotton are mixed together, they approach

equilibrium in moisture content, and the harvested material may rapidly become too damp

to store or gin properly.

Proper care of the harvesting machine is

important in controlling trash and moisture.

Before the season begins, worn parts should be

replaced and all adjustments to factory specifications should be made by trained personnel.

With the spindle picker, cleanliness is most

important. The manufacturer's lubrication

guides should be followed, and excess oil and

grease should be cleaned from the machine

after each lubrication of the picking head. If

oil and grease accumulate in the picking head,

the head should be scrubbed down with a

cleaning solvent.

On stripper machines, the plant lifters and

stripping rolls or fingers should be adjusted

and operated to pick up a minimum of trash

and foreign material from the ground and

from the plants. If the stripper is equipped
with an air blast or other boll-separating device,

it should be adjusted to remove as many green

bolls as possible for early (before-frost) stripping of defoliated or desiccated cotton, to

prevent excessive moisture and heating.

The skill and training of the operator play

an important part in harvesting clean, dry cotton. Each time a spindle picker is stopped to

dump the basket, the operator or a helper

should clean out the picker-head doors and

drum area by hand. He should also keep the

picker basket free of lint streamers. Lint

streamers should never be thrown or allowed to

drop into a load of seed cotton.

Most of the spindle twists, or bow-ties, that

plague ginners are caused by improper adjustment of the spindle-moistening pads and doffers. These adjustments should be checked

visually every time the machine stops to dump.

Improper adjustment is also evidenced by poor

picking efficiency, by dirty, wrapped spindles,

or both. Grass and green leaves wrapped tightly

in the seed cotton contribute to formation of

spindle twist.

The clearance and tension of the pressure

plates in the picker head should be set to suit

the size and condition of the cotton being picked. If the plants are small and most bolls are

open, the pressure plates can be set one-fourth

inch from the tips of the spindles with a yield

pressure of 40 pounds to increase picking efficiency. If the plants are large and green and

if there are many green unopened bolls, the

clearance can be increased to as much as threefourths inch and the yield pressure reduced to

20 pounds. This adjustment will minimize the

loss of green bolls but will reduce the machine

efficiency in the first picking.

The amount of moisture added to the seed

cotton by the picker can be kept at a minimum

of only 1 to 2 percent if care is taken in adjusting the spindle-moistening pads and the

flow of water to them. Only enough water

should be used to keep the spindles clean. The

flow should be adjusted throughout the day,

since less will be required early in the day and

late in the afternoon, when the seed-cotton

moisture is higher. Wetting agents in the water

may help keep spindles clean with slightly

lower flow rates. Textile oils are used in some

areas instead of water for spindle moistening.

Tests have shown that oils keep the spindles

and picker head clean but lower the picking

efficiency of the machine. Also, the small

amount of oil left in the lint after ginning is

not desirable at spinning mills (Colwick and

Shaw 1962).

In some areas considerable cotton is dropped

to the ground by mechanical harvesters. Gleaning machines are available to pick it up. The

foreign matter picked up with the seed cotton

by these machines often requires special handling in the gin and creates ginning problems.

The answer to this problem would be better

control of production and harvesting practices

and better harvesters to improve harvesting

efficiency. By these means, the gleaning operation would be made unnecessary. Until these

im.provements are achieved, however, gleaning

will be a profitable practice in some areas of

the Cotton Belt.

REFERENCES

Colwick, R. F., and Shaw, C. S. 1962. Spindle moistening agents for mechanical cotton pickers : an evaluation. U.S. Dep. Agrie, Agrie. Res. Serv. [Rep.] ARS

42-68, 18 pp.

Parker, R. E., and Wooten, 0. B. 1964. Sources of moisture in mechanically harvested cotton and its effects

on cotton quality. U.S. Dep. Agrie. Tech. Bull. 1313,

25 pp.

Seed-Cotton Storage

By ANSELM C. GRIFFIN, JR.

Storing seed cotton is the inescapable result

of harvesting cotton faster than it can be

ginned. The disparity between harvesting and

ginning rates is sometimes unintentional, but

more often it is the result of planned, coordinated efforts to harvest and gin the crop in

the most profitable manner.

Once the crop has opened, delays in harvesting it usually mean risking quality and quantity losses from the weather, especially from

rainstorms. Thus, there is a financial incentive

to harvest the crop as rapidly as possible, even

if it cannot be ginned immediately.

The most important single factor in determining whether seed cotton can be stored without quality loss to either fibers or seeds appears

to be its moisture content. Agricultural Re-
search Service's work (1972) on small lots of

cotton indicates that seed-cotton storage at

densities up to 12 pounds per cubic foot is possible, without loss in seed quality (based on

germination, free fatty acid content, and

aflatoxin analyses) at the following moisture

levels:

Moisture content of seed

(percent wet basis)

8-10

10-12

12-14

14-15

Days storage

30

20

10

less than 3

Griffin and McCaskill (1964) reported that

seed cotton stored in trailers with cottonseed

at 14 percent moisture suffered loss in lint

grade and bale value because of spotting, and

Montgomery and Wooten (1958) found that

cotton picked early in the morning with 20 percent seed-cotton moisture gave lower lint grades

than cotton picked in the afternoon at 13 percent moisture, when both were delayed 8 to

72 hours before ginning.

There is no convenient, rapid method for accurately determining the moisture content of

seed cotton. The portable moisture meters sometimes found at gins were originally designed

to measure the moisture content of lint only

and are not recommended for determining the

moisture content of seed cotton in the field.

However, there is a high correlation between

cotton moisture content and the ambient relative humidity, which may be readily determined

by using a sling psychrometer or hair hygrometer (which indicates relative humidity directly) ; the moisture content of the seed cotton

on the stalk may then be estimated by referring

30 40 50

RELATIVE HUMIDITY, %

FIGURE 2-1.—Typical moisture content (wet basis) of

cotton fibers, seed cotton, and cottonseed in moisture equilibrium with air at 70° F.

to figure 2-1. Spindle picking may add 1 to 2

percentage points to the moisture content of

seed cotton. It is recommended that cotton for

storage be picked only when the ambient relative humidity is lower than 50 percent. If

harvesting is begun before the cotton has adequately dried, the cotton should be taken to

ginneries for immediate ginning.

The quantity and moisture content of foreign

matter in seed cotton may sometimes determine

whether the cotton may be safely stored. Clean,

dry cotton may be stored indefinitely without

deterioration, but cotton harvested with a high

percentage of high-moisture plant parts, such

as by early stripping, cannot be considered a

safe storage risk. The same is true of the cotton

surrounding the wad of green plant parts that

sometimes collects in the basket of spindle

pickers.

Cotton that is too damp for safe storage

may, in some instances, be dried in gin driers.

Enough moisture must be removed to offset the

higher temperature produced in the seed cotton

by the drying. Agricultural Research Service

studies (1972) showed that two 24-shelf driers

operating at 300° F at the air-cotton mixpoint

should dry dewy cotton enough to permit at

least 7 days' safe storage. Only one stage of

drying can result in merely putting wet cotton

into storage at temperatures favorable for

bacterial damage.

It is usually impractical to attempt to dry

or to cool seed cotton in storage. For this reason, storage facilities may be regarded as

''dead'' storage, and handling machinery is required only for moving cotton into and out of

the facility.

Some of the commonly used storage systems

are conventional cotton transport trailers,

houses or sheds, and free-standing ricks or

modules. Other systems store harvested cotton

in wheelless, trailerlike bins, in piles on turnrows, and as seed-cotton bales; these methods

are not now widely practiced, and some are

more suitable in certain parts of the Cotton Belt

than in others.

HOUSE OR SHED STORAGE

One of the more popular types of storage for

bulk seed cotton consists of one or more large

sheds; when not required for cotton storage,

they can be used for storing equipment or

other items. This type of facility may be used
selector valve

bottom hinged

to reload trailers no.45far

FIGURE 2-2.—Recommended minimum machinery for

moving seed cotton into and out of bulk storages.

Cleaning, extracting, and drying equipment may be

inserted if required.

with a centralized unloading and loading station, with connecting pipe for moving cotton

into and out of the storages (fig. 2-2). Separate fans to unload cotton from trailers and to

blow the cotton to the storage bins are recommended. Such an arrangement results in fewer

chokages and faster unloading than a system

employing only one fan. Machinery sizes and

fan speeds will depend on the intended handling

rate, the condition of the cotton, and the disstance to the storage. Most machine-picked cotton can be handled at a rate of 8 to 10 bales

per hour with a 72-inch separator, 14-inch pipe,

and fan speeds of 1,900 revolutions per minute.

By using overhead delivery pipe along the

centerline and installing 90° swivel elbows at

40-foot intervals, a 40-foot-wide house may be

loaded with a minimum of effort.

One means of unloading such a storage is a

suction pipe, with capped openings at appropriate intervals, laid on the floor before the

building is filled with cotton. To unload the

storage, the most accessible cap is removed and

cotton is hand-fed into the pipe. As the cleared

area increases, 10- or 12-foot lengths of pipe

may be fitted to the opening to facilitate handling. As unloading progresses, additional openings may be used until the building has been

emptied.

After all cotton has been removed, the floor

pipe may be removed so that the entire floor

area is cleared for other uses. In this connection, one or more of the sidewalls may be

hinged or removable to provide easy access into

the building.

A frequent modification of this plan is to

locate the storage facility near enough to the

gin that the trailer-unloading fan(s) in the

gin may be used to draw cotton from the

storage house.

In some areas portable cotton-handling systems are used in a cotton-through-the-fan arrangement so that the same fan may be used

for sucking and blowing the cotton. This arrangement is relatively slow, but it works

reasonably well when it is operated within its

limitations and when seed damage is not

important.

TURNROW STORAGE

Perhaps the most attractive way to provide

temporary seed-cotton storage so that harvesters are not halted for lack of basket dump

and storage space is to store cotton on turnrows. In one method, cotton harvesters dump

into a slip-form stacker or rick former, in

which the cotton may either be compacted by

workers walking on it or by a mechanical compactor. This results in a continuous rick of

cotton of any desired length. Ricks should be

located on well-drained ground areas, from

which the cotton can be picked up by tractormounted front-end loaders or other similar devices, and transferred into conventional trailers

for hauling to the ginnery.

In another method, a module former is used

to shape a smaller stack, which is handled as a

separate load thereafter. The stored cotton

rusts on a wooden or metal pallet that protects

it from ground moisture and provides a means

of loading the cotton undisturbed onto a carrier

for transport to the ginnery. Cotton stored in

this form is usually protected from rain by

tarpaulins. The quantity of cotton that can be

stored in each stack or module will depend to

some extent on cotton moisture content, but

to a greater extent on the compacting force.

Typical weight-space-density relationships are

6 to 7 pounds per cubic foot for cotton footpacked by workers and 9 to 12 pounds per

cubic foot for machine-packed cotton. An advantage, in addition to the larger amount of

cotton stored by packing, is that the stack becomes self-supporting and may be transported

without excessive road loss.

In locations where the risk of rain or groundwater damage is slight, harvesters may dump

their loads in piles directly on the ground for

later retrieval by portable fans, front-end

loaders, drag lines, or other means.

8
REFERENCES Serv. [Rep.] ARS 42-14, 19 pp.

U.S. Agricultural Research Service. 1972. Factors afGriffin, A. C, and McCaskill, 0. L. 1964. Storage of fecting cottonseed damage in harvesting and hanseed cotton in trailers. U.S. Dep. Agrie. Prod. Res. dling. U.S. Dep. Agrie. Prod. Res. Rep. No. 135,

Rep. No. 81,18 pp. 77 pp,

Montgomery, R. A., and Wooten, 0. B. 1958. Lint . 1973. U.S. Cotton Ginning Research Laboratory

quality and moisture relationships in cotton through (Stoneville, Miss.) Annual Report FY 1973, pp. 239-

harvesting and ginning. U.S. Dep. Agrie, Agrie. Res. 250.

SECTION 3.-THE GINNING PROCESS

Green-Boll Traps

By J. W. LAIRD and W. E. TAYLOR

Periodically, early-season machine-stripped

cotton containing many green immature bolls

has caused ginning problems such as clogging

of the sawteeth, failure of the seed roll to turn,

accumulation of sticky material on the inner

surface of the roll boxes and on the saws and

moting surfaces of the gin stands, and occasional clogging of other machines (Wakelyn

et al. 1972). Two causative factors seem to be

involved.

When green, unopened cotton bolls enter the

gin along with mature bolls, many of the green

bolls are broken by the machinery through

which they pass, and some of the green-boll

segments eventually enter the gin stand along

with mature locks. When the gin sawteeth engage the wet lint and soft seed of a green boll,

some of the immature material becomes so

tightly wedged in the sawteeth that it resists

doffing. As the flow of immature locks into

the seed roll continues, additional sawteeth

become clogged, and eventually the seed roll

can no longer rotate. As a result, the gin must

be shut down, and the wet material wedged

in the sawteeth removed by hand.

Also, moisture is transferred from green bolls

(and possibly other wet plant materials) into

dry cotton under certain harvesting and storage

conditions. This wet cotton causes ginning problems similar to those resulting from green

bolls. Cotton and cottonseed, especially when

immature, contain small amounts of substances

that become sticky when wet and are thought

to be at least partly responsible for the gumming of gin machinery. These substances appear mostly in unopened or early-season cotton,

particularly in dry climates. Apparently, they

change with maturation of the cotton or are

degraded by the effects of weathering and are

therefore not troublesome late in the harvest

season.

The use of green-boll removers on stripper

harvesters has alleviated but not eliminated

the green-boll problem. Turnrow storage has

also helped the green-boll problem because the

storage period allows for longer drying, but at

times it has aggravated the moisture transfer

problem. Turnrow storage has also made rock

and clod removal by green-boll traps more

important.

Various devices are used in cotton gins to

remove green bolls from the harvested material

and to prevent their reaching the gin stand.

Some of these green-boll traps are constructed

on the principle that green, unopened bolls

have a considerably greater density than dry,

mature bolls. In most pipes conveying seed

cotton in the gin, the air velocity is such that

both open and green bolls will be transported.

Since the density of the two types of bolls is

different, their separation can be effected in a

chamber where the air velocity is reduced to

such a point that green bolls settle out of the

airstream but open bolls do not.

Another means of separation is by centrifugal

force. Since green bolls are heavier than mature

bolls and since the centrifugal force that acts

on an object is proportional to its weight, the

two types of bolls may be separated by subjecting them to equal angular acceleration. The

mixture of open and green bolls is carried

through a duct that abruptly changes direction.

Being lighter in weight than green bolls, the

open bolls are subjected to less centrifugal force

and more nearly follow the path of the air as

the duct changes direction. The green bolls

tend to continue in the original direction of

travel and are expelled from the airstream into

a suitable collection chamber.

Some green-boll traps employ a combination

of stilling chamber and centrifugal force (fig.

3-1). Because of the variations in design of

this type of green-boll trap, detailed instructions for its operation cannot be given here.

For successful operation, the manufacturer's

recommendations on air velocity and baffle adjustment should be closely followed. The trap

11
adjustable deflector

cleanout door

reclaiming air adjustment

— vacuum dropper

FIGURE 3-1.—Hopper type of green-boll trap.

should be inspected frequently to see that the

baffle and reclaiming air are properly adjusted

for the type of cotton being processed.

The hopper type of green-boll trap shown in

figure 3-1 has been rather widely adopted by

the industry. Most commercially manufactured

units employ the design principles shown here

except for variations in control and adjustment

and in reclaiming. Some use a counterweighted

trapdoor and a short accumulating pipe in place

of the vacuum dropper. The trapdoor is held

closed by suction while cotton is being unloaded,

then opens and dumps by the weight of the

trapped green bolls when the suction valve

cycles to ''off.'' The reclaiming airstream is an

undesirable feature because it reduces the

wagon unloading capacity and increases the

horsepower required for unloading, but it has

been found necessary to prevent loss of open

cotton along with the green bolls. It is desirable

to keep the deflector adjusted as high as possible and the reclaiming air at the minimum

consistent with acceptable green-boll removal.

The power requirement for the reclaiming airstream under typical conditions may be as much

as 15 horsepower for a single unit.

Research to develop better methods for greenboll removal has been underway at both public

and private agencies. One outgrowth of this

work has been the development of effective

green-boll removers mounted directly on the

stripper harvester, reducing the problem before

the cotton gets to the gin (Kirk and Hudspeth

1964). The advent of the overhead basket stripper harvester has helped because, rather than

concentrating the green bolls in one spot in the

lower front of the trailer, it tends to spread

them evenly, producing a lighter, more uniform

load on the green-boll separator in the gin.

discharge

FIGURE 3-2.—Air-jet green-boll separator.

Efficiency is higher, and the ginner can adjust

for lower reclaiming air and less reduction in

unloading capacity. Uniform spreading of the

green bolls in the trailer also helps minimize

moisture transfer and spontaneous heating

problems that tend to occur around accumulations of wet green material.

Turnrow storage offers both advantages and

disadvantages. The long storage period helps

because it may allow sufficient time for the wet

green bolls to dry, but when moisture from

green-boll concentrations migrates to the surrounding dry cotton, it can cause ginning

problems that last for extended periods.

Research effort at the South Plains Cotton

Ginning Research Laboratory is directed toward learning more about the problems associated with ginning green and wet cotton and

toward development of green-boll removal devices that reduce energy requirements and are

effective in removing green bolls that have

been broken up before they reach the remover.

A device called the air-jet green-boll separator is being investigated (fig. 3-2). It is

designed to take maximum advantage of the

different aerodynamic characteristics of green

bolls and open cotton. The unit does not have

to be located in the conveying airstream and

operates at a much lower air pressure, with

corresponding reduction in energy consumed,

and less interference with suction unloading

capacity. In this device the cotton is passed

across a series of air jets, the velocity of which

is adjusted to convey the open cotton but not

the green bolls. The latter fall between the

jets and are removed. The cotton is exposed to

separating conditions for a longer time and in

12
open bolls

rectangular suction duct

feed rate regulator

layer of open S

green bolls

\

7

I ^_ .^^¿S'J^'D^.^y^^OcO^^:^ ^^<^^^^ ^a'<^^

Vgreen bolls

3i>

conveyor belt

FIGURE 3-3.—Conveyor-belt suction-duct green-boll

separator.

a thinner stream, allowing increased opportunity for heavy materials to separate. It can

be located immediately following the unloading

system regardless of the type of system used

and will convey the cotton to the next location.

Research is not yet complete but it appears

promising. The device has shown a capacity

for removing wet cotton, ice, snow, and some

trash from dry cotton, but control may prove

to be too critical in such applications.

Another type of trap (fig. 3-3) developed

at the Oklahoma Ginning Research Laboratory,

although not widely used, is being adopted in

the dump, belt-feed, unloading systems installed

in new, very high capacity ginning plants. In

this trap, a thin layer of the harvested cotton

is deposited on a moving endless belt. A suction

duct near one end of the trap lifts open bolls

from the layer of material, while the green

bolls, tramp iron, rocks, and clods remain on

the belt and are discharged over the end. This

trap removes 87 to 92 percent of green bolls,

with a lint loss of less than one-fourth pound

per bale when used on cotton containing up

to 11 percent green bolls. It also removes a

considerable number of sticks and bollies.

An ounce of prevention is certainly worth

a pound of cure when it comes to green-boll

removal. A ginner should make every effort

to get this material removed as close to the

stripper harvester as possible. Where waiting

for the bolls to dry on the stalk is practical,

this is the best solution, but often other considerations override it. Problems start to occur

at a green-boll content of approximately 10 percent. Other variables, such as moisture content

of bolls and cotton, relative humidity and temperature, time, and condition of storage between harvest and gin are involved. Sometimes

concentration of green material in a small

volume within a load can cause problems that

would not have arisen with the green material

more scattered. However, scattering is not always an effective solution, because at green-boll

contents slightly greater than 10 percent the

entire load can be affected so that none of it

can be ginned. Scattering does improve the

efficiency of green-boll removers and works

where it keeps the green-boll concentration in

any part of the load below about 5 to 6 percent.

The same general rule also applies in field

storage, to prevent the development of hot

spots.

REFERENCES

Kirk, I. W., and Hudspeth, E. B., Jr. 1964. Development

and testing of an improved green-boll separator for

cotton-stripper harvesters. Trans. ASAE 7: 414-417.

Laird, J. W., and Baker, R. V. 1973. Removal of greenbolls from seed cotton by air jets. Am. Soc. Agrie.

Eng. Pap. No. 73-342, 15 pp.

Wakelyn, P. J., Loewenschuss, H., Roark, B. A., and

Laird, J. W. 1972. Constitution of the deposit on the

inner surfaces of gin roll boxes. Text. Res. J. 42:

597-600.

Cotton Moisture Control

By ANSELM C. GRIFFIN, JR.

There are two principal reasons for controlling cotton fiber moisture content in ginneries:

for smooth operation of the processing machinery and for obtaining the optimum fiber

quality from the seed cotton delivered to the

ginnery.

Cotton with too high a moisture content will

not readily separate into single locks and will

form wads that may choke, warp, or break

ginning machinery. Cotton too low in moisture

may also cause machinery stoppages by clinging

to metal surfaces as a result of static electricity

generated on the fibersDamp cotton does not clean as well as dry

13
18

17

16

15

14

13

12

II

^.10

|9

^ ft ce Ö

UJ 7

û: '

3

en 6

o

2 5

: , : :

....

f

^ ' ' ' ' . . ■■: rr: 1 - : -: pif ec 4>iwt tJoned V "7//

/

- --* - -

/

f

: : : .

//

::::i::,:

' 1

' î :' * '

t '

/

^:

...

: : :

• ' •

—---' -

j;!: /^l

>^

: ; : :

-^7'7\'y

:/ -

^^^.-^—j.—.._,.-^.- ^:::^

A /

7

tîon éd <

.; i:.i: :...:^^. /^iii. '-'y

-'./ y

/

nuond Iry

/^

':':—- :_.,:.. 1. .:.:.:.

.. , , 1 "^~'^''

.... j

0 10 20 30 40 50 60 70 80 90 100

RELATIVE HUMIDITY, %

FIGURE 3-4.—Relationship of cotton fiber moisture

content (dry basis) to ambient relative humidity at

70° F.

cotton. Before the widespread use of lint cleaners, some ginners sought to obtain the highest

grades possible by drying the cotton to moisture

levels that are now considered unsafe for fiber

length preservation. Research has established

that the apparent strength of cotton fibers is

directly proportional to fiber moisture content

and is therefore greater at higher moisture

levels. Consequently, as fiber moisture content

is lowered, as by drying, the apparent strength

is reduced and the frequency of fiber breakage

during ginning is increased.

Fiber moisture content from 6.5 to 8 percent

gives smooth saw gin operation and profitable

lint grades while holding the fiber breakage

rate to a reasonably low level. Although cotton

can be processed at moisture levels higher than

8 percent and lower than 6.5 percent, the risk

of operational or quality-control problems increases as the fiber moisture content departs

from that range. In roller ginning, a fiber

moisture content of 5 to 6 percent is desirable.

Cotton is a hygroscopic material. Consequently, its natural moisture content varies in relation to the relative humidity of the surrounding

air. A typical relationship between raw cotton

fiber moisture content and ambient relative

humidity is shown in figure 3-4.

Cotton harvested during periods of high

humidity may arrive at ginneries with a moisture content as high as 12 percent or more, and

cotton harvested during periods of low humidity

may contain fiber moisture of 4 percent or less.

For these reasons, ginneries seeking to gin lint

at a predetermined moisture content must be

prepared to add as well as remove moisture

from the cotton being processed.

DRIERS IN GINNERIES

The first heated-air driers for use in cotton

ginneries were developed by the U.S. Department of Agriculture in the period 1926-32.

These included moving trays and drag belts,

but the most successful and widely used drier

has been the shelf type in which cotton is

conveyed through the drier by the heated air

(fig. 3-5). Other types of driers, such as counterflow, mechanical reel, screw conveyor, and

combination cleaner-driers, have also been used.

The physical dimensions of tower driers vary

among manufacturers; most conventional tower

driers are 4 to 6 feet wide, about 6 feet long,

and 17 to 20 feet high. The number of shelves

varies from about 16 to 24, and the spacing

between shelves varies from 8^2 to 10 inches.

Larger driers are available, but most gin driers

in use today fall within the limits given.

The cotton-handling capacity of tower driers

may range from 8 to 30 bales per hour, depending upon drier width, condition of the cotton,

and quantity of air moving through the system.

Spindle-harvested cotton processes faster

through tower driers than stripped or snapped

cotton because it contains less waste. Rain-wet

and other relatively dense cottons must be

handled with care to prevent choking because

of temporarily overloading the conveying system. The most critical locations in the drying

system are in the pipe immediately below the

bulk feed dropper and in the first few shelves

at the top of the tower, where the air velocity

is suddenly lowered as it moves from the con14
/ ,^9'm •*#-''- ••* •••

».• *-

«It» «^v^^^flfA ^^^M ^

*'- , ,• •

»/#•••'•«•»> * M ,-•''

..a«'^,.^

¿•*r#Mr«#^^***

- «,"•••*

#/i*t**». »^J *** •••'»*'

•.••r»*«.»*» '

r^

FIGURE 3-5.—Typical shelf tower drier for drying seed

cotton in ginneries.

veying pipe into the drier. In commercial practice, air velocity in the cotton-conveying pipe

ranges from 4,000 to 5,000 feet per minute,

and in the driers, the velocity may be reduced

to only one-half of the conveying velocity.

There is some slippage between cotton and

air, this being greatest for damper, heavier,

denser cottons. As the cotton is opened and

fluffed by moisture removal and mechanical

action, it is more easily airborne, and its final

velocity more nearly approaches that of the

conveying air. Cotton is seldom in a gin drying

system for as long as 15 seconds; 7 to 10 seconds

is common.

The first driers were heated by steam coils,

FIGURE 3-6.—Typical gin drying system. A fan and

burner deliver heated air to the air-cotton pickup

point, and a second fan is usually used to aid in

conveying cotton through the system.

with drying air temperature initially at about

160° F. But cotton roughly harvested and harvested during periods of high humidity called

for removal of more moisture, requiring the

use of higher drying temperatures, more than

one stage of drying, or both. Modern drying

systems are capable of serious overdrying and

must be regarded as quality hazards if they are

not used properly. Most of the moisture removal

takes place in the first 3 seconds after the cotton is exposed to the heated air, and drying-air

temperatures in excess of 350° F at the aircotton mixpoint may have serious adverse effocts on fiber quality. Therefore, the use of

two or more stages of drying at relatively low

temperatures is preferable to a single stage at

higher temperature.

The typical gin drying system consists of a

heater, one or more fans, piping, shelf drier,

and seed-cotton cleaner that serves the dual

purpose of separating the warm moist air from

the cotton and cleaning the cotton (fig. 3-6).

There are wide variations in the layout of

ginneries, so that air requirements and drying

exposure periods may be expected to differ

from gin to gin. Because of these wide variations, Agricultural Research Service's laboratories refrain from recommending specific

operating temperatures (except that in no case

should the temperature in any portion of the

drying system exceed 350° F).

The location of temperature control sensors

is important. Many bales have been overdried

and some have been set afire through overheating, even though the sensing device indicated a safe drying-air temperature. When the

temperature sensor is located well into the drying system—near the bottom of the drier, for

15
1 5.0

bulk-cotton

/

cot ton-conveying pipe 1

/ \

254°F ^ ^

feed hopper

@damp

^tton _^ !

^^' ^ air heater

4.5

/ J^ \cylinder

tower drier /^ /^ ^^SS ^'^^^^'^

' \^yWl34°F

4.0

^Q 3.5

/ f \ \ \ warm-air

tennperature / [ ^ ] pyhnii<it control point / Vl^ ^xnausT

/72°F 1

f

><

3.0

FIGURE 3-7.—^Temperature gradient observed in a commercial gin drying system with the temperature

control point located near the bottom of the tower

drier.

example—the temperature at the air-cotton

mixpoint may be considerably higher than that

indicated by the sensor (fig. 3-7).

Mixpoint temperatures as high as 450° F

have been observed with a control point temperature of about 180° F. It is recommended

that the temperature control sensor be located

in the hot-air line just ahead of the mixpoint.

If this is not practicable, then a temperature

high-limit switch at this location set for 350° F

is recommended to prevent scorching and

ignition of cotton in the drying system.

Gin drying systems originally consisted of a

single processing line, with machinery sized to

meet production rate requirements, but modern

hourly processing rates may often require dividing the seed-cotton stream for adequate drying. The ginning machinery manufacturers'

recommendations should be followed with

respect to equipment size and processing rate.

The pace of modern ginning is too rapid

for ginners to examine each load of cotton and

adjust the drying system accordingly; all U.S.

ginning machinery manufacturers offer some

type of automatic drier control. These controls

permit the plant to reduce the variability of

moisture content of the finished bales and may

offer considerable energy savings by adjusting

the heater fuel to the amount actually needed

to remove excess moisture from the cotton and

by cutting the burners back to low flame when

no cotton is in the drying system.

A study of heat use by a tower drier at the

U.S. Cotton Ginning Research Laboratory,

Stoneville, Miss., showed that a drying system

having uninsulated pipe and an uninsulated

P 2.5

2.0

1.5

1.0

0.5

100 200 300 400 500 600 700

TEMPERATURE, T

FIGURE 3-8.—Heat-to-temperature relationships for air

moving through a gin drying system from an

initial temperature of 70° F.

steel tower drier used only about 16 percent

of the heat supplied by the air heater to remove

moisture from the cotton. The remainder of

the added heat was lost by radiation or passed

from the system as warm air.

The amount of fuel used by gin drying systems may be estimated in several ways. The

simplest method is to relate fuel purchases to

bales ginned, making allowance for fuel not

used by the cotton driers. When the volume of

air moving through the drying system is known

(see "Fans and Piping''), a thermometer in the

air line near the heater will provide a basis

for estimating fuel consumption. From figure

3-8, the heat added to the air may be read on

the vertical axis for a known air volume at a

given temperature. For example, if the drying

system is pulling 5,000 cubic feet of air per

minute and its temperature near the heater is

300° F then the heat being supplied is estimated at about 1.25 million Btu per hour.

Assuming a combustion efficiency of 95 percent

and using the heat values of table 3-1, the

quantity of fuel required to yield 1.25 million

16
Btu is about 1,300 cubic feet of natural gas or

about 14.4 gallons of commercial propane.

A sampling of 48 cotton ginneries in Arkansas and Missouri in 1960-61 showed that an

average of about 430,000 Btu was required to

dry a bale of cotton. In terms of quantity of

fuel consumed, this was about 381 cubic feet

of natural gas or about 4.4 gallons of the conventional butane-propane mixture per bale

(Holder and McCaskill 1963).

MOISTURE RESTORATION

Since the fiber breakage rate during ginning is inversely proportional to the fiber

moisture content at the gin stand and lint

cleaners, the number of fibers that break may

be minimized by conducting the fiber-seed

separation and lint-cleaning processes at as

high a moisture level as practicable.

Much of the American cotton crop is harvested during low-humidity periods and often

arrives at the ginnery with fiber moisture from

4 to 5 percent. The average fiber length of

such cotton may be improved by adding moisture before fiber-seed separation and lint cleaning, by reducing the number of fibers that

break in the gin stand and lint cleaners. But

restoration of moisture to ginned lint will not

improve fiber length. Other benefits resulting

from moisture restoration include reducing the

static electricity level of the cotton and reducing the amount of power required to pack and

press a bale of cotton (see 'Tackaging'').

Methods of moisture restoration have included

introducing humid air from vapor generators

into extractor-feeders, feeder chutes, and lint

flues; creating a fog or mist through which

seed cotton must fall or be conveyed; and spraying moisture on ginned lint as it passes from

the final lint condenser to the press box.

There is a practical physical limit to the

quantity of moisture that may be added to seed

cotton. Wetting of the cotton by uncontrolled

emissions or by unexpected condensation within

TABLE 3-1.—Nominal heat content for some

fuels used in drying systems at ginneries

Fuel Heat content

Natural gas 1,000 Btu/ft'^

Commercial butane 102,600 Btu/gal

Commercial propane, HD 5 91,500 Btu/gal

Propane/butane (40/60) 97,800 Btu/gal

Fuel oil, CS No. 2 140,000 Btu/gal

machinery and pipes must be prevented or

chokages will result. Gin stand operation becomes irregular and may cease altogether if

liquid water pervades the seed-cotton mass.

Cotton with fiber moisture of 9 percent or

more may not gin smoothly and will not process

properly through the lint cleaners. Thus, the

recommended fiber moisture level of 6.5 to 8

percent has a ginnery production aspect as well

as a quality aspect.

A development of the Southwestern Cotton

Ginning Research Laboratory at Mesilla Park,

N. Mex., called the monoflow cotton conditioning system, is based on the hygroscopic nature

of cotton and its tendency to approach moisture

equilibrium with the surrounding air (Gillum

et al. 1973). In the monoflow system all the

conveying air is maintained at a specified relative humidity. This causes overwet cotton to

give up moisture and overdry cotton to absorb

moisture toward a preselected target moisture

level of about 7 percent.

An automatic moisture control system that

dries with heated air and adds moisture on

demand from a single measurement at the seed

cotton input hopper has been demonstrated at

the U.S. Cotton Ginning Research Laboratory,

Stoneville, Miss. The system has been modified

to include fog nozzles in the distributor for

moisture addition at high ginning rates (Griffin

and Mangialardi 1967).

Provision for moisture restoration should be

a part of plans for new ginneries or for remodeling older plants. Moisture restoration

facilities will insure that ginneries are able to

maintain the inherent cotton fiber length properties in spite of harvesting and ginning

weather conditions.

REFERENCES

American Society of Heating, Refrigeration, and AirConditioning Engineers. 1972. Handbook of fundamentals, pp. 167-176. The Society, New York.

Bennett, C. A. 1928. Seed cotton drying apparatus.

(Moving trays, vertical travel.) U.S. Patent No.

1,695,991.

. 1929. Process and apparatus for drying seed

cotton. (Moving trays, horizontal travel.) U.S. Patent No. 1,707,929.

1929. Seed cotton drying apparatus. (Vertical

chute drier.) U.S. Patent No. 1,707,930.

-. 1932. Apparatus for drying seed cotton. (Tower

with stationary shelves.) U.S. Patent No. 1,871,773.

(This patent contains an excellent discussion of the

cotton-drying process and principles involved.)

17
. 1932. The vertical seed cotton drier. U.S. Dep.

Agrie. Misc. Pub. 149, 8 pp.

-. 1937. Apparatus for drying seed cotton. (Airline cleaner-drier.) U.S'. Patent No. 2,078,309.

-, and Gerdes, F. L. 1939. The vertical drier for

seed cotton. U.S. Dep. Agrie. Misc. Pub. 239, 31 pp.

, and Shaw, C. S. 1938. Overhead cleaner-dryer

systems. U.S. Dep. Agrie. Misc. Pub. 314, 20 pp.

-, Stedronsky, V. L., and Martin, W. J. 1940.

Sources of heat for cotton drying. U.S. Dep. Agrie.

Misc. Pub. 383, 22 pp.

Chapman, W. E., Jr. 1971. Effects of temperature and

humidity of Pima and Upland seed cotton in sealed

cans on ginning performance and fiber and seed

quality. U.S. Dep. Agrie, Agrie. Res. Serv. [Rep.]

ARS 42-182, 15 pp.

Cocke, J. B., and Garner, W. E. 1972. Effect on ginning

and spinning efficiency and cotton quality of fiber

moisture, seed-cotton cleaning, and lint cleaning. U.S.

Dep. Agrie. Prod. Res. Rep. 143, 14 pp.

Franks, G. N., and Shaw, C. S. 1969. Multipath drying

at cotton gins for controlling moisture in cotton.

U.S. Dep. Agrie, Agrie. Res. Serv. [Rep.] ARS

42-69, 12 pp.

Garner, W. E., and Mullikin, R. A. 1964. Effects of

certain drying treatments in ginning on fiber properties and spinning performance of Southeastern cotton,

crop of 1960. U.S. Dep. Agrie. Prod. Res. Rep. 85,

16 pp.

Gerdes, F. L. 1950. Cotton drying practices in relation

to quality and efficiency of ginning. The Cotton

Ginners' Journal and Yearbook 18(1) : 26-27.

, Martin, W. J., and Bennett, C.A. 1939. Drying

seed cotton. U.S. Dep. Agrie. Leaf. 181, 8 pp.

, Rusca, R. A., and Stedronsky, V. L. 1941. Drying of seed cotton at gins. 27 pp. Agricultural Marketing Service and Bureau of Agricultural Chemistry

and Engineering, U.S. Department of Agriculture.

Gillum, M. N., Leonard, C. G., and Wright, T. E. 1973.

Monoflow: control of moisture and reduction of air

pollution by using monoflow air system. The Cotton

Ginners' Journal and Yearbook 41(1) : 4-10.

Grant, J. N., Harold, E., Andrews, F. R., and Griffin,

A. C, Jr. 1962. Drying, cleaning effects on cotton

fiber properties. The Cotton Gin and Oil Mill Press

63(15): 7, 46-47.

Griffin, A. C, Jr. 1964. Prevent fiber breakage. The

Cotton Gin and Oil Mill Press 65(10) : 18, 35-36.

Cleaning and Extracting

By W. E. GARNER and R. V. BAKER

The need for seed-cotton cleaning and extracting equipment in the gin has developed

gradually through the years to cope with

rougher harvesting methods. The development

of the seed-cotton drier has greatly expanded

the use of cleaning njachinery in the gin because dry cotton can fee cleaned much more

readily than damp cotton.

The terms ^'cleaning'' and ''extracting'^ as

. 1964. Bringing fiber moisture under control.

The Cotton Ginners' Journal and Yearbook 32(1):

15, 17, 20.

-, and Harrell, E. A. 1957. Effects of moisture

added at the lint slide on lint quality, and bale weight

in humid cotton production areas. U.S'. Dep. Agrie.

Prod. Res. Rep. 14, 16 pp.

-, and Mangialardi, G. J., Jr. 1961. Automatic

control of seed cotton drying at cotton gins, a review

of research. U.S. Dep. Agrie, Agrie. Res. Serv.

[Rep.] ARS 42-57, 14 pp.

-, and Mangialardi, G. J., Jr. 1967. Another

first—a completely integrated moisture control system for gins. The Cotton Gin and Oil Mill Press

68(11): 7.

and Mangialardi, G. J., Jr. 1970. Some considerations in the design of an electrode system for

measuring the moisture content of cotton. The Cotton

Gin and Oil Mill Press 71(9) : 7, 8.

Harrell, E. A. 1956. Apparatus for the restoration of

moisture to the fibers of seed cotton. U.S. Patent No.

2,764,013.

Holder, S. H., and McCaskill, O. L. 1963. Costs of

electric power and fuel for driers in cotton gins,

Arkansas and Missouri. U.S. Dep. Agrie, Econ. Res.

Serv. [Rep.] ERS 138, 12 pp.

Jorgensen, Robert (ed.), 1970. Fan engineering, pp.

523-537. 7th ed. Buffalo Forge Co., Buffalo, N.Y.

Leonard, C. G., Ross, J. E., and Mullikin, R. A. 1970.

Moisture conditioning of seed cotton in ginning as

related to fiber quality and spinning performance.

U.S. Dep. Agrie. Mark. Res. Rep. 859, 16 pp.

Mangialardi, G. J., Jr., and Griffin, A. C, Jr. 1966.

Lint cleaning at cotton gins : effects of fiber moisture

and amount of cleaning on lint quality. U.S. Dep.

Agrie. Tech. Bull. 1359, 24 pp.

, Griffin, A. C, Jr., and Moore, V. P. 1968. Cotton ginning system having automatic seed cotton

conditioner. U.S. Patent No. 3,392,424.

-, and Griffin, A. C, Jr. 1968. A moving bed

drier for cotton research. U.S. Dep. Agrie, Agrie.

Res. Serv. [Rep.] ARS 42-14.0, 11 pp.

Perry, J. H. (ed.). 1963. Chemical engineers' handbook,

section 15. 4th ed. McGraw-Hill, New York.

Speakes, C. C, and Griffin, A. C, Jr. 1956. Method of

moisture restoration to cotton. U.S. Patent No.

2,747,234.

used in the ginning industry, refer to processes

normally performed by separate and distinct

machines, although some machines may do both

cleaning and extracting. Cleaners usually employ a series of beater cylinders and concave

screens or grid bars. These cylinders, with a

tip speed of about 2,000 feet per minute, convey

the cotton through the machine, scrubbing the

locks of cotton over the concave surfaces and

permitting the trash to sift out. The size of

the openings limits the kind and size of trash

18
that can be scrubbed through. Therefore, only

the smaller particles of broken leaf, dirt, and

small sticks and stems can be removed with a

minimum loss of cotton locks. Extractors accomplish trash removal by a toothed cylinder

that seizes the cotton locks and slings the trash

off by centrifugal force or removes it by striking against stripper rollers or grid bars. Clearances are large enough to convey the locks of

cotton safely through, but the burs and larger

pieces of trash are stripped off. The trash is

directed to augers for discharge, while reclaimers pick up waste cotton locks and return

them to the main cotton stream.

Cleaners and extractors can be either bulk

machines or unit machines. As bulk machines,

they handle all cotton being processed through

the gin and are normally located in the overhead preceding the distributor. Unit machines

serve only one gin stand and usually combine

the process of cleaning and extracting, plus

regulating the flow of cotton to the gin stand.

Cleaning is necessary in a gin to improve

both gin stand performance and lint grade, but

there are practical limits to both. Removal of

trash reduces wear and tear on the gin stand,

and cleaning improves gin stand efficiency by

presenting cotton to it in small, uniform units.

Removal of trash is also associated with grade

improvement, but there exists a point of diminishing returns where the benefits of further

trash removal are offset, by fiber and cottonseed damage and excessive loss of weight. Most

modern gins contain cleaning equipment to

handle the most severe trash condition that

is expected in their areas. However, actual use

of cleaning equipment should be based on the

incoming trash content of the cotton, and cleaner cottons should not be processed through

every cleaning machine in the gin just because

it is available. Bypass valves should be provided

to omit certain machines for the cleaner cottons;

trash removal should be restricted to that which

is necessary to produce the grade determined

by the color of the cotton. Further cleaning

reduces the weight without increasing the value

of the bale.

The range and type of trash in seed cotton

varies throughout the Cotton Belt. Trash can

be characterized as bolls, burs or hulls, sticks

and stems, leaves, motes, grass, weeds, dirt,

pin trash, and even tramp metal. Table 3-2

gives typical trash contents by types for cottons

harvested by three machine methods. These

methods account for over 99 percent of the

cotton harvested in the United States.

In 1972 there were 3,710 cotton gin batteries

in the United States. Information on seed-cotton

cleaning equipment installed in cotton gins at

that time is shown in table 3-3.

CYLINDER CLEANERS

Fine trash, leaves, and dirt are removed from

seed cotton by machines generally classified as

cleaners, or specifically as cylinder cleaners.

The cylinders are usually spiked drums that

open and clean the cotton by conveying and

scrubbing it across surfaces with openings that

allow the trash to sift through. The cleaningsurface configuration leads to further classification of cylinder cleaners as either screen,

{Continued on page 22.)

TABLE 3-2.—Foreign matter in bales of cotton

harvested by three methods

[Pounds per bale]

Machine- Machine- MachineForeign matter ^.^^^^ stripped scrapped

Hulls 29 450 329

Sticks and stems 9 115 143

Leaves and dirt 43 135 398

Total 81 700 870

Source: A. M. Pendleton and V. P. Moore. 1967.

Ginning cotton to preserve fiber quality. U.S. Dep.

Agrie, Ext. Serv. [Rep.] ESC-560, 19 pp. Includes

revised estimates.

TABLE 3-3.—Cotton gin batteries with specified

kinds of seed'Cotton cleaning equipment

[3,710 batteries. United States, July 1972]

Batteries having equipment

Machine —— —- Number Percent

Bur extractor 2,113 57.0

Stick and green-leaf machine • 2,147 57.9

Combination! 400 10.8

Magnet 1,609 43.4

Green-boll trap 2,417 65.1

Other- 3,479 93.8

1 Combination bur extractor, and stick and green-leaf

machine.

- Includes all other seed-cotton cleaning equipment

such as impact and incline cleaners, after cleaners, etc.

Source: Agricultural Marketing Service, Cotton Division. Cotton gin equipment, 1972. 16 pp.

19
FIGURE 3-9.—Inclined screen cleaner

FIGURE 3-12.—Flow of cotton through an inclined

cleaner.

FIGURE 3-10.—Inclined cylinder cleaner equipped with

grid-rod screen.

FIGURE 3-13.—Flow of cotton through a seven-cylinder

revolving-screen cleaner.

FIGURE 3-11.—Seven-cylinder inclined cleaner.

20
FIGURE 3-16.—Air-line cleaner.

FIGURE 3-14.—Five-cylinder revolving-screen cleaner

equipped with grid-rod reclaiming cylinders.

FIGURE 3-17.—Flow of cotton through an air-line

cleaner.

FIGURE 3-15.—Stick, leaf, and pepper trash extractor

cleaner equipped with six cleaning cylinders plus

an extracting unit.

21
grid bar, or revolving screen (impact). The

screens may be either woven wire or perforated

metal. A typical screen is made of 2- by 2-mesh,

0.105 woven galvanized wire cloth (fig. 3-9).

Screen cleaners have largely been replaced by

more efficient grid-bar cleaners that have %-

inch-diameter rods spaced five-sixteenths to

five-eighths inch apart (figs. 3-10—3-12). In

the revolving-screen, or impact, cleaner the

cotton is conveyed across a series of revolving

serrated disks. This cleaner also has a reclaiming cylinder (figs. 3-13 and 3-14). Some

models of grid-bar cleaners have extracting

sections (fig. 3-15).

Cylinder cleaners may also be classified as

to how they are normally used in a cotton gin.

In this respect they are either air-line, hot-air,

or gravity-fed cleaners.

Air-line cleaners may have cylinders of the

spiked-drum or crusher-plate type that permit

only a horizontal flow of the seed cotton from

the inlet to the outlet of the machine (figs. 3-

16 and 3-17). They allow both air and seed

cotton to pass entirely through the cleaner.

Air-line cleaners are popular in the High Plains

of Texas and in western Oklahoma as an effective means for removing sand from cotton and

for breaking the bolls for further cleaning.

Hot-air and gravity-fed cylinder cleaners

may have the cylinders arranged in an inclined

or horizontal position (fig. 3-18). Hot air may

enter the cleaner through a blow-in or push-pull

fan arrangement. In many cases the first cleaner serves as a cleaning separator following the

first drier. It may discharge into an extractor

or a gravity cleaner for further cleaning (fig.

3-19).

For gins having a capacity above 12 to 14

bales per hour, two 6-foot-wide cleaners are

usually installed in parallel, with each cleaning

half the seed cotton under a split-stream

arrangement.

The efficiency of cylinder cleaners is generally low when considered as individual machines; the efficiency is calculated from

seed-cotton fractionation tests before and after

cleaning. However, they are not normally used

alone, but in combination with other machines,

and serve a most useful function in opening the

cotton or breaking up large wads and removing

fine trash such as leaves, sand, and dirt. Since

they do remove trash, they can improve grade

as more cylinders of cleaning are added. NatPN-5233

FIGURE 3-18.—Seven-cylinder dual-inlet inclined

cleaner, 140 inches wide.

FIGURE 3-19.—Hot-air cleaner discharging into a

gravity cleaner.

urally, higher cleaning efficiencies are

associated with cotton of higher trash content.

In early tests the cleaning efficiency of a

seed-cotton cleaning setup consisting of a tower

drier at 160° F, a bur machine, a seven-cylinder

cleaner, and an extractor-feeder was reported

to be 57.7 percent (Moore and Merkel 1953).

When the cylinder cleaner was placed ahead of

the bur machine in the system, cleaning effi22
1—KICKER CONVEYOR

2—LARGE SAW OR EXTRACTING CYLINDER

3—STRIPPER HOLLER

4—DOFFING BRUSH

5—SPIKED CONVEYOR

8—SCREEN

7-TRASH CONVEYOR

FIGURE 3-20.—Bur machine.

ciency increased to 71.8 percent. In later tests,

the total cleaning efficiency of overhead seedcotton cleaning and extracting systems for machine-picked cotton has been reported as 54 to

86 percent (U.S. Agrie. Mark. Serv. 1958,

Garner et al. 1970, Cocke and Garner 1972).

The trash removed by a seven-cylinder cleaner

has been reported to be 11.7 to 14.7 pounds per

1,000 pounds of seed cotton, from machinepicked cotton with an input trash content of

4.6 percent (Cocke 1972). In another test the

individual cleaning efficiency of a six-cylinder

cleaner was reported as 18.0 to 23.4 percent,

on machine-picked cotton with input trash

content of 7.0 to 17.3 percent (Read 1972).

Specifications of commercially available cylinder cleaners, as furnished by the manufacturers, are given in table 3-4.

EXTRACTORS

Burs and sticks are extracted from seed

cotton by specially designed equipment generally classified as extractors. The trade usually

refers to extractors by type, i.e., bur machine,

stick and green-leaf machine, and extractorfeeder.

Bur machine.—The bur machine was developed in the 1920's in response to hand snapping and mechanical stripping of cotton in

Texas. The bur machine has been widely adopted by the ginning industry, especially in stripper-harvesting areas. In 1973, 57 percent of

all U.S. gins and 89 percent of all Texas gins

had bur machines (U.S. Agrie. Mark. Serv.

1973).

The bur machine utilizes a dislodging or

stripping principle for extracting burs and

sticks from seed cotton. Seed cotton is fed to

a large-diameter saw cylinder by a kicker conveyor, which is a conventional auger with angleiron flippers attached to the conveyor flighting

(fig. 3-20). Seed cotton adheres to the sawteeth and is carried past a stripping point near

the top of the cylinder. At this point a flighted

stripper roller, which clears the tips of the sawteeth by one-fourth to one-half inch, dislodges

burs and sticks from the surface of the cylinder

and discharges this material back into the

kicker conveyor. The kicker conveyor moves

the dislodged material (including burs, sticks,

fine trash, and some seed cotton) to one end

of the machine, where it falls onto a spiked

conveyor. The spiked conveyor moves the dislodged material back along the entire length of

the saw cylinder so that seed cotton can be

reclaimed from the dislodged material. Fine

trash and dirt sift through a screened bottom

to another auger located underneath the spiked

conveyor.

Bur machines are usually employed about

midway through the seed-cotton cleaning and

drying processes. Normally, a bur machine is

preceded by one stage of drying and a cylinder

cleaner. They can be employed in single units

or, for high-capacity gins, as multiple units in

parallel, but are seldom operated in tandem.

Bur machines manufactured by the various

gin machinery companies are similar in design

and size. The saw cylinder is approximately 30

inches in diameter and operates at a speed of

110 to 140 revolutions per minute. The stripper

roller is approximately 12 inches in diameter

and operates at a 4-to-l speed ratio with the

saw cylinder. The operating speeds of the

kicker conveyor and doffing brush are approximately equal to that of the stripper roller. Bur

machines are supplied in lengths of 10, 14, and

18 feet, and have capacities of about one-half

bale per hour per foot of length. Approximately

three-quarter horsepower per foot of length is

required to operate these machines.

23
í3 C

-t-J a;

Co u 2

^ «4H H <^ y n

1

5>

o

o

i

CO

Ci

o

Ö

CO<^

•


I CO

w

w

<:

H

QÍ o

-e o ^

Co "^ "^

O OS -P

es

O Co '^

5H "-^

72

<^ ?! í¿ \

g s 2|

ft

5 &^

ri=!

•r-l *fH

^ lO lO lO LO lO

(N (N (N (M* (N <N

I I I I I I

t^ O O l> O O

TH (N c^i TH (>â ci

LO iO lO

CM* (N C^*

O O O O O O

CN (M* C<Í (M' (M* C^

(M (M Oa

t- O O

W lO O lO lO O O p p

P00000<>3 00

t> O O t> O O CO c^* cvi c^* CO <^í' c<i c<i (N c4 c^' (JL) (^i c<i (N

TH c4 (N TH C<Í C<i rH TH r-í

' O iO iO O »O

I Cjl (N TH cg (M lo

no O lO

lO T-l (M C3

LO O O lO O O lO

OLOOOIOOO'^^

TH rH (M TH TH (M TH

^ ^ ^ O) O) o;

^ ^ ^ O O O

lO (M CD Tj< (M ÇÛ LO

I I I I I I I I £^ 2 ^1

O O O O O O o

O O O O O O lO

LO lO LO "^ "^ "^ iX>

O O O

o o o

-^ Tí< '«:}<

Oí o

ft3

O O O O O

o o o o o

l>-t-t>LOLOLOLOLO

O O O I I I I I

o LO LO LO LO

^ "^ T}< "^ "^

O

O

O O »^ LO LO LO

LO LO I LO LO LO

"^ T^i O r^ Tt -rj^

O

O O O

O O O

ÇD <X> <X)

î£)ÇO<X)t>LOLO ^t>

Gi a a c:i Gi Oi

ZD ZD ^ ^ ^ ^

íOOOOCDCAO IíOOOCQ

CÖft

A <î Ä

ix ^ g *5 >. 'r§

-M -M O

O <v

Ä fH

^

TJ bß TD

<t) <D

.s Ti

P .s

ü a o

p c

o

A <

o CÖ

p

Co o

o '^

o

H

C«

í3

»-3

CÖ

T3

to

o

ftft

<

O

Í3

!=5

O

>

xn

Í3

24
Feed control

spider •

grid bon

Wir«

brush

rtclotmtr

Single brush

doffs two sows

Grids under

rtcloimer sows

FIGURE 3-21.—USDA-developed stick remover.

The cleaning efficiency of a bur machine is

dependent to a large degree upon the amount

of trash in the seed cotton. Highest efficiencies

are obtained when cleaning high-trash-content

cotton. When extracting machine-stripped cotton, the bur machine can be expected to be

about 65 percent efficient in removing burs

and 35 percent efficient in removing sticks

(Baker 1971 and Franks and Shaw 1959). Finetrash removal by a bur machine is very low.

In many cases, seed cotton will contain more

fine trash after extracting with the bur machine than before extracting, because the bur

machine tends to pulverize the large trash particles and produces more fine trash than it removes. This situation is particularly noticeable

when processing seed cotton containing very

dry and brittle burs and sticks.

The cleaning efficiency of the bur machine

on machine-picked cotton is lower than it is on

stripped cotton. The bur machine can be expected to remove 7 to 12 percent of the total

trash from machine-picked cotton (Read 1972).

FIGURE 3-22.—Gravity-fed, two-saw stick machine with

steel doffing cylinder.

Fine-trash removal from machine-picked

cottons is also low.

Stick and green-leaf machine.-—The stick and

green-leaf machine (fig. 3-21) was developed

by USDA in the early 1950's to meet the more

stringent cleaning requirements imposed on

gins of that era by the rapidly expanding practice of harvesting cotton mechanically (Franks

and Shaw 1959). The basic principle introduced

by USDA was rapidly adopted and further developed by gin machinery manufacturers. Early

stick and green-leaf machines were sold as

attachments for bur machines, but these attachments have been gradually replaced with individual machines commonly referred to as stick

machines, stick removers, sling-off machines,

or stick and green-leaf machines. The principle

has also been incorporated into modern highcapacity extractor-feeders. In 1973, 59 percent

of all U.S. cotton gins were equipped with at

least one stick machine (U.S. Agrie. Mark.

Serv. 1973).

Stick machines utilize the sling-off action of

high-si)eed saw cylinders to extract foreign

matter from seed cotton by centrifugal force

(fig. 3-22). Seed cotton is fed onto the saw

cylinder, either by air or by gravity, and wiped

25
TABLE 3-5.—Sizes and characteristics of commercially available stick and fjreen-leaf machines

Primary sling-off Approximate

„ - , , , Widths saw cylinder capacity per

Manufacturer and make availahlp :;; í; ;— , ,.•,., avaiiaoie Diameter Speed foot of width

^ ' (inches) (r/min) (bales/hour)

Continental / Moss-Gordin :

Little David 6,8 13% 363 1-2

Super II 6,8,10 16 320 1.5-2

Super III 8,10 16 340 1.5-2

Hardwicke-Etter :

Hustler, AG 6,8 18 315 1

Hustler, G 6,8 18 300 1

Hustler, G-2 6,8,12 18 365 1.3-1.5

Lummus:

Little Giant 6,8,12 17% 260-350 1.5-2

S. & G.H. Machine 8,12 30 140-150 1.5-2

Murray:

H-L-S-T 6,8,10 20 330 1.6-1.8

Compact Machine 6,8 20 330 1.6-1.8

1 Air or gravity for 6- and 8-foot widths, gravity only for 10-foot width.

Horsepower

requirements Feeding

per foot of method

width

1.7 Air or gravity.

1.9-2.5 Do.

1.9-2.5 Gravity.

1.7-1.9 Air or gravity.

1.7-1.9 Gravity.

2-2.5 Do.

2-2.5 Air or gravity.

3.3-3.8 Do.

1.9-2.5 Do.i

1.9-2.5 Gravity.

FIGURE 3-23.—Gravity-fed stick, leaf, and hull remover.

onto the sawteeth by one or more stationary

wire brushes. Foreign matter is slung off the

saw cylinder by centrifugal forces 2.5 to 35

times that of gravity. During this process, some

seed cotton is extracted with the trash. Grid

bars or additional wire brushes are strategically

located about the peripheiy of the saw cylinder

to control this loss of seed cotton. However, it

has been found that some loss of seed cotton

is unavoidable if satisfactory cleaning efficiencies are attained. Additional saw cylinders are

used to reclaim the seed cotton extracted with

the trash. Reclaimer saw cylinders resemble

the sling-off saws, but usually operate at slower

speeds and are equipped with more grid bars.

Stick machines are usually preceded by one

or two stages of drying and at least one stage

of cleaning. They may be fed by air or gravity;

the trend in recent years has been to gravity

feeding by a separator or cylinder cleaner.

Gravity feeding is more uniform and less

troublesome than air feeding, and a cylinder

cleaner opens stripped cotton for more efficient

cleaning by the stick machine and reduces seedcotton losses. Depending upon capacity requirements, stick machines may be employed as

single or multiple parallel units.

Table 3-5 summarizes the sizes and characteristics of commercially available stick machines. Machines are available in widths of 6,

8, 10, and 12 feet for approximate single-unit

capacities of 9, 12, 15, and 18 bales per hour.

26
FIGURE 3-24.—Gravity-fed, two-saw stick machine with

saw doffing cylinder.

FIGURE 3-25.—Gravity-fed, two-saw stick machine with

brush doffing cylinder.

FIGURE 3-26.—Extractor utilizing both stripping

mechanisms and sling-off forces.

respectively. Some models of stick machines

have two sling-off saws (fig. 3-23), while

others use only one (fig. 3-24). All models

have at least one reclaimer saw. The trend in

recent years has been to use one large-diameter

(16 to 18 inches) sling-off saw and one

reclaimer saw (fig. 3-25).

Most stick machines use a stationary wire

brush to implant the cotton fibers firmly into

the sawteeth. However, one model uses a feeding method somewhat similar to a bur machine

(fig. 3-26). This model, which was designed for

stripper and ground-salvaged cotton, also contains a stationary stripper in addition to

brushes and grid bars.

Cleaning efficiencies of stick machines vary

widely depending upon the condition and trash

content of seed cotton. For machine-stripped

cotton, commercial stick machines can be expected to remove approximately 65 percent of

the burs, 50 percent of the sticks, and 10 percent of the fine trash (Baker 1971, Baker and

Laird 1973). The efficiency for machine-picked

cotton is about 13 to 20 percent for total trash

in the seed cotton (Read 1972).

27
FIGURE 3-27.—High-capacity feeder with extracting

and cleaning features.

FIGURE 3-28.—High-capacity feeder with two stages of

sling-off extraction.

FIGURE 3-29.—High-capacity feeder utilizing sling-off

extracting principle.

Extractor-feeder.—Gin stand feeders with

extracting capabilities have been used since the

early 1900's (Bennett 1962). Early extractorfeeders were based on the stripping or dislodging principle utilized by bur machines. However, after development of the stick machine,

most manufacturers abandoned the stripping

principle in favor of the stick machine's more

efficient sling-off principle. Also, the introduction of high-capacity gin stands in the late

1950's forced manufacturers to simplify and

streamline feeders in order to achieve desired

capacities. This was accomplished by adopting

the sling-off principle of a stick machine (figs.

3-27—3-29).

The primary function of a modern highcapacity extractor-feeder is to feed seed cotton

to the gin stand uniformly and at controllable

rates, with extracting and cleaning as a secondary function. The feed rate of seed cotton

is controlled by the speed of two star-shaped

feed rollers located at the top of the feeder

directly under the distributor hopper. These

feed rollers are powered by variable-speed hy28
draulic or electric motors, controlled manually

or automatically by various interlocking systems with the gin stand. The drive may be

designed to automatically start and stop as the

gin breast is engaged or disengaged; the system

may also be designed to stop feeding seed cotton

in cases of gin stand overloads or underloads.

Many of the systems are designed to maintain

constant seed-roll densities. This is usually accomplished by modulating the speed of the feed

rolls in response to feedback control signals

from the gin stand, generated by (1) monitoring the power consumption of the electric motor

driving the gin stand, (2) measuring displacements of the cove board in a seed-roll box, or

(3) monitoring the pressure required to drive

a hydraulically powered seed-roll agitator.

REFERENCES

Baker, R. V. 1971. Comparative performances of a

stick machine and a bur machine on machine-stripped

cotton. U.S. Dep. Agrie. Tech. Bull. 1437, 16 pp.

, and Laird, W. 1973. Extracting sticks from

machine-stripped cotton. Trans. ASAE 16: 497-499.

Bennett, C. A. 1962. Cotton ginning systems and auxiliary developments. Texas Cotton Ginners' Association.

Cocke, J. B. 1972. Effect of processing rates and speeds

of cylinder-type cleaners on ginning performance and

cotton quality. U.S. Dep. Agrie, Agrie. Res. Serv.

[Rep.] ARS 42-199, 9 pp.

-, and Garner, W. E. 1972. Effect on ginning and

Gin Stands

By T. E. WRIGHT and VERNON P. MOORE

The gin stand is the heart of the gin plant.

The capacity of the plant and the quality and

potential spinning performance of the ginned

lint depend on the stand's being in good condition and in proper adjustment. The gin stand

can affect every commonly measured fiber

property except fiber strength and micronaire.

All stands are adjusted before leaving the

factory, but during handling and shipping the

settings may change. It is therefore important,

even in new gins, to check all settings and to

make necessary adjustments in accordance with

the manufacturer's instructions. A number of

points are common to practically all gin stands,

and attention to these details will contribute to

better operation and preservation of quality.

Some of the more important adjustments and

settings for various makes and models of gins

are shown in figures 3-30 through 3-3.5. Machinery manufacturers will furnish up-to-date

manuals that give detailed instructions on

installing, adjusting, and operating their gin

stands.

spinning efficiency and cotton quality of fiber moisture, seed-cotton cleaning, and lint cleaning. U.S.

Dep. Agrie. Prod. Res. Rep. 143, 14 pp.

Pranks, G. N., and Shaw, C. S. 1959. Stick remover

for cotton gins. U.S. Dep. Agrie. Prod. Res. Rep.

22, 39 pp.

Garner, W. E., Shanklin, E. H., and LaFerney, P. E.

1970. Fiber quality and ginning performance of machine picked and stripped cotton, Southeastern area,

1964-66. U.S. Dep. Agrie. Mark. Res. Rep. 852,

30 pp.

Moore, V. P., and Merkel, C. M. 1953. Cleaning cotton

at gins and methods for improvement. U.S. Dep.

Agrie. Cire. 922, 50 pp.

Pendleton, A. M., and Moore, V. P. 1967. Ginning cotton

to preserve fiber quality. U.S. Dep. Agrie, Ext.

Serv. [Rep.] ESC-560, 19 pp. (Includes revised estimates.)

Read, K. H. 1972. Cylinder cleaner speed influences

cleaner efficiency. The Cotton Gin and Oil Mill Press,

Nov. 25, 1972, pp. 6-7.

U.S. Agricultural Marketing Service. 1958. Effects of

cleaning practices at gins on fiber properties and

mill performance of cotton. U.S. Dep. Agrie. Mark.

Res. Rep. 269, 20 pp.

. 1972. Cotton gin equipment 1972, 16 pp.

. 1973. Cotton gin equipment, July 1973.

FIGURE 3-30.—Important settings and adjustments for

Continental/Moss-Gordin Comet 141 saw-brush gin.

1, Saw projection through huiler rib, % ". 2, Gravity mote board to brush, 1%". 3, Overhead mote

board to saw, ñ:". 4, Ginning point to point of rib,

2". Saw speed, 700 revolutions per minute (r/min).

Brush speed, 1,850 r/min.

29
® (i)

FIGURE 3-31.—Important settings and adjustments for

Hardwicke-Etter Regal 224 dual saw-brush gin. 1,

Saw projection through split rib, à". 2, Saw

projection through gin rib, 2%". 3, Huiler knife

projection into saw, %" to %". 4, Brush to saw,

throat of tooth. 5, Lower cutoff plate to brush,

fff" or closer. 6, Upper cutoff plate to brush, Vs".

7, Mote board to saw, T^;" to :?!". 8, Mote board

to brush, lA". 9, Lower mote board to saw, %".

10, Airgap, nonadjustable. 11, Upper scroll to saw,

•^". 12, Top brush scroll to brush, V*" minimum.

Upper saw speed, 695 revolutions per minute

(r/min). Lower saw speed, 650 r/min.

When installing new equipment, the gin stand

should first be placed in correct alinement with

the other machinery, leveled, and bolted to the

floor before any adjustments are made. After

checking the settings and making the necessary

adjustments, the gin breast is placed in the

ginning position and the saw cylinder rotated

by hand to make sure that all parts are clear

and that no foreign objects are within the gin

stand. Before running the gin stand at full

speed, "jog" the drive motor to see if all cylinders of the gin stand are free to turn. Then

turn the motor on and check the saw speed.

It is very important that the saw speed be

very close to the recommended speed, since as

little variation as 20 to 25 revolutions per minute above or below the manufacturer's recommendations can make an appreciable difference

in performance.

Gin manufacturers have made their gin

stands as safe to operate as they know how;

however, gin stand operation still can be hazFlGURE 3-32.—Important settings and adjustments for

Lummus Imperial 128 saw-brush gin. 1, Saw projection through huiler rib, W to "ü". 2, Brush to

saw, depth of sawteeth. 3, Mote board to saw, Vi".

4, Mote board to brush, 1%". 5, Overhead mote lip

to saw, Vs". Saw speed, 830 to 855 revolutions per

minute (r/min). Brush speed, 1,770 r/min.

FIGURE 3-33.—Important settings and adjustments for

Murray 142-18 brush gin. 1, Saw projection

through huiler rib, I'.i". 2, Ginning point to point

of rib, 2". 3, Brush to saw, depth of sawteeth.

4, Foot of huiler rib to ginning rib, 3". 5, Mote bar

to saw, :i':.". Saw speed, 545 revolutions per minute.

30
FIGURE 3-34.—Important settings and adjustments for

Lummus Imperial 128 saw airblast gin. 1, Saw

projection through huiler rib, W' to /ii". 2, Airblast

nozzle to saw, -k".. 3, Airblast mote board to saw,

Vi". 4, Airblast throat opening, It?". 5, Overhead

mote lip to saw, %". Saw speed, 830 to 855 revolutions per minute. Airblast pressure, 16" to 19" of

water.

FIGURE 3-35.—Important settings and adjustments for

Murray 120-18 airblast gin. 1, Saw projection

through huiler rib, ^t". 2, Ginning point to point

of rib, 2". 3, Airblast nozzle to saw, A". 4, Foot

of huiler rib to ginning rib, 3". Saw speed, 456

revolutions per minute. Airblast pressure, 10" to

16" of water.

ardous unless proper precautions are taken.

Other than the manipulation of the normal

operating controls, no adjustments or maintenance should be attempted while the gin stand

is in operation. The gin stand should always be

stopped and the power turned off and locked

out before making adjustments to the settings

or attempting maintenance work.

GIN BREAST

After installing new stands or repairing old

ones, be sure that the lateral adjustment of the

breast is correct. The saws should be positioned

in the center of the rib slots. After visual inspection, the saw cylinder should be rotated

slowly by hand to make certain that none of the

saws rub the ribs.

When the gin breast is removed from a gin

stand, it should be identified with that gin

stand, and special care should be taken to be

sure the breast is reinstalled on the same gin

stand from which it was removed.

When replacing a broken rib, care should be

taken to install the replacement so that the saw

opening is the same on each side. It is generally

more satisfactory to have worn ribs replaced

by the manufacturer or a competent gin service

company. A matched set of ribs installed by

well-equipped and experienced personnel will

usually give better service than unmatched sets

installed without proper jigs.

Never move the breast into ginning position

when there is seed cotton in the roll box, unless

the saws are running. To do so may damage

the ribs or buckle the saws.

On many gins the picker roller is adjustable.

In some cases it can be adjusted by means of

a ratchet lever while the gin is in operation.

Generally speaking, it should be set as far away

from the saw or huiler ribs as possible without

dropping cotton. The closer the picker roller

is set to the huiler ribs, the less space there is

for hulls to fall out and the more the saw will

break the hulls up and pull small pieces into

the roll box with the cotton.

The seed fingers, or lambrequin, should be set

as widely open as possible but close enough that

the seed will be clean. When building up a new

roll, close the seed fingers and then slowly open

them as widely as possible, consistent with

clean seed, to allow the cleaned seed to fall out

of the roll box. Holding seed in the roll box

longer than necessary will reduce the ginning

81
FIGURE 3-36.—Critical saw-rib dimensions (A, B, C,

and D) vary with manufacturer's make and model.

Specifications should be followed for maintaining

cotton quality and gin stand capacity.

rate and cause tight seed-roll operation, which

reduces the value of the cotton.

The relation of the saws to the ribs is critical.

Consult the manufacturer's manual to determine which of the dimensions shown in figure

3-36 should be checked to insure proper saw-rib

relations.

GIN SAWS

Saws should be checked to make sure they

are properly trained and are running in the

middle of the rib slots at the recommended

speed. If the distance from the point where

the saws project through the ginning rib to

the top of the rib is not correct, capacity will

be reduced and fibers will be damaged. The

distance the saws project through the huiler

ribs should also be checked. If the saws project

too far, an excess of hulls and sticks will be

pulled into the roll box. If the saws do not

project far enough, ginning capacity will be

reduced, seed cotton will fall out of the front,

and the huiler ribs may choke.

The pitch and shape of the sawteeth are also

important in maintaining capacity and cotton

quality. To insure good ginning, the teeth must

PITCH

ANGLE

GINNING RIB

FIGURE 3-37.—Leading edge of the tooth should enter

the ginning rib parallel to the rib surface, or the

point of the tooth should lead the throat slightly.

Saws should never be filed or breast adjusted so

that the throat leads the point of the tooth. CL =

centerline.

pass through the ribs at the proper angle. The

point of the tooth should enter the ginning rib

slightly ahead of the throat (fig. 3-37). If the

saws are improperly filed or the saw-rib relationship is improperly adjusted so that the

throat of the tooth enters the rib ahead of the

point, the resulting cutting action will reduce

capacity and break fibers and may cause chokages at the top of the ginning ribs. In many

instances, the moting action of gin stands is

affected by the sawteeth being tilted too far

forward or backward.

Saws should be examined frequently, and

bent teeth should be straightened or even

broken off so that lint will not remain hung in

them. Lint that cannot be doffed will tend to

collect in the low part of the gin ribs. If this

lint is allowed to accumulate, the friction of the

32
FIGURE 3-38.—For proper doffing, the gin brush should

be set to mesh with the saw the depth of the sawteeth.

saw will cause it to catch fire and can damage

the saws. A heat-damaged saw that wobbles

cannot be retrained and should be replaced or

cut out immediately. Lint collected in the bottom rib slot can also be grabbed by the saw

when the stand is disengaged, possibly breaking

the ribs and damaging the saws.

The number of bales that can be ginned

between changes or sharpening of the saws

depends on the type of cotton being handled

and on the material the saws were made from.

Rough cotton causes more wear on the gin saw

than clean cotton, regardless of the type of

steel used. Modern gin saws are made from

stronger, more durable steel than older saws,

which has resulted in greatly increasing the

useful life of the gin saw. The high-capacity

gin stands of current and older design are

equipped with such durable saws that they can

gin 2,000 to 3,000 bales per stand before changing. Processing trashy cotton with minimum

overhead cleaning will make more saw changes

necessary. The general practice in high-capacity

ginning is to replace rather than attempt to

sharpen worn saws. Sharpening of saws is still

essential for the older outfits, especially those

equipped with 80, 90, and 120 12-inch-diameter

saw stands. Usually, saws of these older model

stands should be sharpened after ginning 400

to 900 bales per stand, depending on the number

of saws per stand and the type of cotton being

ginned. Sharpening reduces the diameter of the

saw. After several sharpenings, gin capacity

will have been so reduced that new saws are

needed. Many ginners find it uneconomical to

continue to use saws that have been sharpened

more than three or four times. Saws should be

sharpened by the manufacturer or a competent

gin service company. However, if a ginner

elects to sharpen his own saws, he should take

extreme care to maintain the original tooth

shape and pitch. The edges of the teeth should

be deburred after sharpening.

When changing saws, it is best to keep saws

of the same diameter on a mandrel. If new saws

are mixed with saws that have been reduced

one thirty-second or one-sixteenth inch in

diameter, it will be impossible to adjust the gin

breast properly to the saws. At least one spare

saw cylinder should be on hand during the

ginning season.

DOFFING SYSTEM

Brushes,—For proper doffing, the brush

should mesh to the depth of the sawtooth (fig.

3-38). Belts driving the brush must be kept

tight to maintain proper speed for doffing and

to provide sufficient air velocity in the lint flue

to prevent backlash.

The brushes should be examined periodically

and replaced if the bristles are badly worn.

They should be returned to the manufacturer

for repair if facilities are not available in the

field for rebalancing them. Brushes that are

out of balance will cause excessive vibration

and bearing wear.

When replacing brushes in the stand, take

care to adjust the shaft and bearings to eliminate lateral motion or *'end play'' and to check

the setting of the brush to the saw, mote board,

and cutoff plate according to the manufacturer's

recommendations.

Airblast nozzles.—The manufacturer gives

specific instructions for setting the airblast

nozzle for each model of gin stand; follow these

instructions to insure proper doffing and

moting.

Keep the nozzle clean and free of tags, and

avoid damaging the nozzle or the gin saws

when removing a saw cylinder. Many tags may

be prevented by periodically removing the cap

from the end of the airblast trunk and starting

33
TABLE 3-6.—Saws and capacities of various makes and models of gin

stands recommended by manufacturers^

„ , , Saw Saw

Manufacturer ^«del cylinders diameter ^^^^ Capacity

y««^ (No.) (inches) (No.) (bales/hour)

Bush-Hog/Continental 1962 1 12 120 3-3.5

Do 1962 1 16 79 4

Do 1962 1 16 119 6

Do 1973 1 16 93 6

Do 1973 1 16 141 7.6

Hardwicke-Etter Co 1962 1 12 120 8

Do 1973 2 (2) 178 6

Do 1973 2 (2) 224 6-8

Lummus Industries, Inc 1962 1 12 88 4-6

Do 1973 1 12 128 8

Murray-Piratininga 1962 1 12 120 3

Do 1962 1 18 80 4-5

Do 1968 1 18 94 5-6

Do 1968 1 18 120 6

Do 1973 1 18 142 8

' Data are averages and will vary considerably for different types of cotton.

2 Bottom saw, 12 inches; top saw, 11% inches.

the fan to blow out the accumulation of dust

and fly.

Check the airblast pressure frequently to

make certain that correct doffing pressure is

being maintained. For most gins, the correct

pressure will be in the range of 10 to 19 inches

of water. Sufficient pressure should be maintained to give proper doffing without wasting

power. Manufacturers can supply an adjustable

airblast fan valve by which the air pressure can

be readily adjusted (fig. 3-39). It is important

that the airblast fan inlet be equipped with a

screen to keep foreign matter out of the fan.

It is equally important that the screen be kept

clean.

MOTING SYSTEM

Modern gin stands are equipped with both

overhead and gravity moting systems. The seals

on the overhead moting system, whether dropper wheel or roller type, should be kept in good

condition. In some gins, pressure is maintained

in the overhead moting chamber, and the system will not operate properly if the seals leak

PN-6234 excessively. Honeydew and green wet lint somePiGURE 3-39.—Airblast fan equipped with intake times cause motes to be sticky and build up on

control vanes, screen, and screen wiper. the moting bars, wiper flights, and roller seals,

drastically reducing moting system effectiveness. Under extreme conditions the buildup will

cause chokage in the gin ribs. When sticky

motes are encountered, clean the moting bars

and seals frequently with fine steel wool, and

34
coat the surfaces with a light textile oil, silicone,

or Teflon spray.

Proper adjustments are also important on

gins having a mote board in the gravity moting

system. To adjust the mote board, open it slowly

until it starts dropping lint, then close it slightly. The wider the mote board can be opened

without losing lint, the more effectively the

system will operate.

Lint Cleaning

By GiNO J. MANGIALARDI, JR.

Lint cleaners were developed specifically for

removing leaf particles, motes, grass, and bark

left in the cotton by seed-cotton cleaners and

extractors. They have been developed and improved in conjunction with the transition from

manual to mechanized harvesting of the cotton

crop, which is virtually complete. Nearly all

gin batteries in the United States have lintcleaning facilities, and over four-fifths of all

gin batteries with lint cleaners have two or

more stages of cleaning (U.S. Agrie. Mark.

Serv. 1972). The lint cleaners now being marketed are of two general types, the flow-through

air type and the controlled-batt saw type.

FLOW-THROUGH AIR LINT CLEANER

The flow-through air lint cleaner, commercially known as the air jet, has no saws,

GINNING CAPACITY

The high-capacity gin stands now on the

market are the result of years of research. They

will give good service as long as they are kept

in good condition and in proper adjustment.

Manufacturer's capacity recommendations for

1962 and 1973 model gin stands are given in

table 3-6. The gins can be made to gin faster,

but the quality of the cotton will be reduced.

brushes, or moving parts. It is usually installed

immediately behind the gin stand. Loose lint

from the gin stand is blown through a duct

within the chamber of the cleaner. Air and

cotton moving through the duct make an abrupt

change in direction as they pass across a narrow trash-ejection slot (fig. 3-40). Foreign

matter that is heavier than the cotton fibers

and not too tightly held by fibers is ejected

through the slot by inertial force. The amount

FIGURE 3-40.—Unit flow-through air lint cleaner, usually located behind the gin stand (Lummus SuperJet lint cleaner).

FIGURE 3-41.—Feed works of a controlled-batt saw

lint cleaner (Bush-Hog/Continental Gin Cleanmaster lint cleaner).

35
FIGURE 3-42.—Unit controlled-batt saw lint cleaner

with brush doffing (Bush-Hog/Continental Gin

Sixteen-D lint cleaner). !

of trash taken out by the air jet is controlled

by opening and closing this cleaning slot (which

can be completely closed). Vane-axial fans pull

the air and lint to suction condensers, where

air and cotton are separated. A critical factor

in the operation of air cleaners is that a vacuum

of 2 to 214 inches of water must be maintained

in the duct on the discharge side of the cleaner.

Flow-through air lint cleaners are less effective in improving the grade of cotton than saw

lint cleaners, but they also remove less weight

from the bale. Fiber length and strength are

unaffected by the air lint cleaner (Griffin and

McCaskill 1957; St. Clair and Roberts 1958).

CONTROLLED-BATT SAW LINT CLEANER

The controlled-batt saw cleaner is now the

most common in the ginning industry. Lint

from the gin stand or another lint cleaner is

formed into a batt on a condenser screen drum.

The batt is then fed through one or more sets

of compression rollers, passed between a very

closely fitted feed roller and feed plate or bar,

and fed onto a saw-cylinder (fig. 3-41). Each

set of compression rollers rotates slightly faster

than the preceding series and produces some

FIGURE 3-43.—Unit controlled-batt saw lint cleaner

with air suction doffing (Lummus model 66 or 86

lint cleaner).

thinning of the batt. The feed roller and plate

grip the batt so that a combing action takes

place as the sawteeth seize the fibers; the feed

plate clears the saw by about one-sixteenth

inch. The teeth of the saw cylinder convey the

fibers to the discharge point. While the fibers

are on the saw cylinder, which may be 12 to

17 inches in diameter, they are cleaned by a

combination of centrifugal force, scrubbing

action between saw cylinder and grid bars, and

gravity assisted by an air current. The fibers

may be doffed from the sawteeth by a revolving

brush, airblast, or air suction (figs. 3-42 and

3-43). When brush doffing, the ratio of the

36
FIGURE 3-44.—Bulk saw lint cleaner (Bush-Hog/Continental Gin Cleanmaster lint cleaner).

tip speed of the brush to the tip speed of the

saw varies from about 1.5:1 to 2:1. The principal features and settings of saw lint cleaners

are given in table 3-7, and their recommended

installations and power requirements are given

in table 3-8.

An important factor in the operation of the

cleaner is the condition of the batt as it is fed

to the saws. If the batt is thicker on one side

than on the other, or if it is too thin or broken,

the lint cleaner will not operate properly. Poor

batt conditions can also cause chokages and may

damage the equipment. A good batt can be

obtained only by having the proper air balance

between the gin stand, the condenser, the duct

fan, and the lint flue. Axial or vane-axial fans,

often referred to as clean-air fans, are usually

FIGURE 3-45.—Unit saw lint cleaners in series

(Hardwicke-Etter Conqueror dual lint cleaner).

used to discharge air from lint cleaner

condensers.

COMBING RATIO AND SAW SPEED

In saw lint cleaners the uniformity and thickness of the batt and the manner in which it

is delivered to the sawteeth are important factors in the effective operation of the cleaner.

These factors are controlled by the manufacturer, but, in some cases, may be modified

by the ginner by regulating the combing ratio

and saw speed of the lint cleaner. Combing

ratio is the ratio of the rim speed of the saws

to the rim speed of the spline feed roller.

Increasing the combing ratio and saw speed

increases the cleaning efficiency of the cleaner,

but can affect the spinning qualities of the

cotton. Most lint cleaner installations operate

within a combing ratio range of about 16 to 28

at saw-cylinder speeds of 800 to 1,200 revolutions per minute (2,515 to 5,025 feet per

minute saw-tip speed) for normal feed rates.

The ginner should not attempt to change these

settings without first consulting the manufacturer. Higher ratios and saw speeds will

{Continued on page A1-)

87
O

Q

a

fe

ft § 'S

O) o w

O) -M fe

O ^ !

'S

s

H2

O)

¿X)

O O O 00 ^ o o o o o

Q Q Q -^ gP Q p Q

-^ S

p

00 ^ ;: o .2 o .2 ^- Ä K

pq

_, ^ X -^ JS -^ 'Tí "T -

g --5 ^^ í= .S ? .S .^ S ^

pq W

Í3 P

PQ

.I'M <

¿ ^* O O O O

o Q) "^ 'Ö 'o "^

±j O)

O

^i'N

o

.s* I

o

(N

O

d

1^5

1^CQ '^CJ

O f^

o

o ''

• O ft -^ O

. O CO O

biD

,S O O O O

ÍH "Tí '^ T3 Tí ft

O

n3

03

be

•S

ft

w

I

be

S

O

O

^3

O

*-M

O

O) W

CO ^*

'S ¿o

^ ft

'3 ^

J» J'=*J^J^ J^ J(Nj«oJ«5 l'^^ J» J«> HS

HS^ H2 ;^ ;^;^;:^;^ ;^ ;:^

Tl< (M ^ ^ Tt '^ T}< Tjí Tjl 1^ CO

Iß LO lO LO LO LO

o

O o o

lO

866

0-80,000

°í T-l

¿ o TH o

00 l> 00

o

o

o

o o o

LO o o

o^ o^ o

o rn" T-T T-T T-T TH

o I ) Î II

00 o o o o o

o o o o o

00 00 00 00 00

•TÍ« TJ< CO CO Ç£> Ç£i

o

o

LO

I o

o

o

CO CO

ë «o

ü o

C 00

•7 LO

K .í

PQ

^ PQ

o fe

s p

03

s

so

03

Pí

« ís«

j. ¿4 C ^J

^ ^ -g o

g o ^ ü

I ^ ^ ;^ ^ ;. 1^ 2 O) OÍ a> O) O) flj

g ft C ft > ftTS

^ í3 o í3 Q¿ 3 o

ü OQ ü CZ2 tí CO ^-3

r^ ;=!

o o

LO Til

.. CD 00

^ r-H r-H Oí <D <D

be T3 TJ C o o

o o

LO Tf

CD 00

o C g

LO (V

cß Co

g "'S

Ü bß

> be

o

p

o

be

.s

Co Oí

o TS

C c3

^ o

ü be

LO

o

o

o

ÇQ

LO

o

o

I o

LO

o

o

o

o

be

o

fw

o PÖ o

^ o

•? be

H

o

«o

o

o

I o

LO

o

LO

o

o

I o

o

00

o

o

•^

¿o

00

o

00

a

I o

o

2

5 ^

P o

CD

00

o

a;

f>r 00

lu

T—1

'ä>

OJ

T3

O o >» i

SS CÖ O ^

Í3

S

38
o

ooo

LO LO IÄ IÄ i> í> t- tr- O O O o

I' I* I* I' o o o o

iO) ia lo ïja o o o o o o o .g

TJ T3 noI O

OO

CO ÇO o o

oo

¿OOO

LO LOo

oo

"^ TÍ<^^

'^ Tj< Tjí ÇO o o o o o o

-^ c^ c^

TH TH r-To

OOO 00

O 00 00 o 00 00

rf t> C- ttí o (M Tj< ^

CO i> 00Ö

bfi bp bj)>

s iSsá

ss

ao

s§^ a; C ft

^H CO

5<J

2I

-o

5Í

COoO

•
Ö

COoi

CO

so

1

^^

<;í

1

'S

^

s n.

«H 1

r^U 1 0 °?

•«1 S O cq % ñ < A Ul H

>> OJ

.t: ft ^_^ ^ w ^ ^ s í3 ft'S O

c3^

Ä

^e

T3

tó w

T3

a; ft

>>

íí

^W &5 ?í -^Ü3

r^SO

Ö C3Ö

0) I

O)

'bJD

T3

03

tí

*S) O

o»,g

tí^

rtí CÔ

'^ 'o -13

rH ÍO CO ÇD

(M

OO

iH

. (N D4 1 00 00 1 O 1 00 1 OÜ

TH t- rH t- T-\

-e tí o

O)

T3tí

03u

-»2 -p -p

'tí *tí *tí ? ?3 í3

>»fH >»?-lh;H

Q) <U «U

4J 4S 4-> -P •r-J ^J -M -p

tí C^ C^ CQ P M pq W

Îè

p cä

-p . g ^ § .tí .tí 2 s s

pqW

S tí a> tí

,£5

bC

r^S^

tí

Ö 'S

4J CÔ tí

-p

0

ëë . tí

fl

S '1

c^ tí "^ «s .tí 1m

§§ i§

^

-P b&S Oí •p=3

;&Oí ft p -p Î2 -p

03 CÖ

ft t^

mw CQ

CÖ^ tí

tíO

-P ?H

•^ O»

ftí^

^^

bX) tí

bí

<D

Is

CO

PQ

tí

LO 000

(M (N CN

OI

:-IL

<>

ft

ÇO CO Y—

1

(M rU < 1

ft2

> PL4

CO

COo

< : d :

to

COo

< : Q : o

cuft

LO

dd

p^

<d

o

EH

o; ft

(M<d

-p

O

rH CO 00 LOW

;:^ I I

"^ Tí< 0^00

00

00

0

0 '^

(>í <N Tf Tí< \a 10 LO LO (M

tí 3o •-'

Ö

^ tí-V ^ ^ CO

r! X.

o

00

LO

CO

iií í^ 'CJ s o tó

ü

03O

ow

'O; 42

^^

tí ft>

o tí

Pí

O)

í>

a;

Pí

O)

tí

CO

LO1 I Ci

•73tíCÖ

.5S

be5

^'tí

tí «: I o

C<1

CO^

ä ft

e. -P

5. -P^

00^ iH

(N '^ <M jj ^ U ^.^ < ft< tí

>> tí

^ ;-i tí a> 0) ft í^ <1)

LO CÖ

P

-r rÛ

0

CO iH O

(M

O

(M

tí

O) O

0

m

ü0

0 9.

10 Tí< -p

^ .. «0 00

0

2^^ -H tí

-p

-P 0) O) 'ÖJ

0

H bxi'O 'ü

0 1 tí 0 0 «H s Sw

tí

P3

n3

CÖ

39
S «î í:í S <ï> 5

es

r—^

c8

B

Bo

(M

es

a>

o o

W ft

o

Pi «

O

W

Ö c3 C

Ü ^ ^^

-a

fi O

'^ S -I ^

S"

TJ.S fi --^

•fi ci

o

'O

fi

o

^ fi

fi

OS

fiii

-S'a

QT fi

Ci 'o '^ Ü

ft eö CO ',3

^ Sc5 &

fi

CO

(U

'S)

*SQ fi

S >» eS CQ

ill^-2T? 0) O <1> Ü

fi

^ IS ftis ft§^^ilft§^2Î 2 'S •

ftt; ^ -e

S ft

«3 fi « fi

.5 ^

pq

T3fi

OS

%fi

T3fi

bo

C3 CO

¿ '2^ i

fi

g*a

^ M «

.tí ^ "^ ^ fi fi

fi £ S fi

:^ w « fi

PQ

o

0)

pq

o ft «

CO «»^ fi

.^rfi S

^ ^ tí

fi

00

o '"^ ft

00 ^ (M ^. fi ri 00

ft CO ^ <î o <

>

ft "^

:: fi

00 ^

2 fi ft "^

^^-fi o

5: Sí '^

fi

(1>

fi

^ .tí

*2 fi

O

CO CO

o O

CO

Co fi

o 8^

CO

ê

O

^ '5'S

r c rt

CO »fi

o 0)

-s^i^

^

N

O

CO

o

¿

-g

'O

o

.. ^

^^ '7Í

^ '^

q> O

c

o

o

"^

00

t—*

Qi

T3

O

CO

CQ

B

s CO

»^ CO

C

CQ T3

fi O

fi

<o «o

CO 00 ^ p_,

a> a>

TJ »TS

0 0

^ S

40
FIGURE 3-46.—Bulk back-to-back, split-stream saw lint

cleaners (Bush-Hog/Continental Gin Super-Constellation lint cleaner).

result in high fiber breakage and nep counts,

while lower ratios and speeds considerably

decrease cleaning efficiency (Mangialardi

1970).

MULTIPLE LINT CLEANING

Lint cleaners are referred to as unit or bulk

(battery), depending on whether they process lint from one or more gin stands. The unit

cleaner is located behind a gin stand and receives lint only from that stand (figs. 3-40,

3-42, and 3-43). This is always the case for

the air lint cleaner. A bulk cleaner receives

lint from two or more gin stands (fig. 3-44).

Two lint cleaners, either unit or bulk, placed

in series so that the same lint passes through

both of them results in what is variously called

tandem, dual, or double lint cleaning (fig.

3-45).

For high-capacity gin stands, the bulk cleaners are installed back-to-back with a common

lint flue (fig. 3-46). In that way the lint from

all the gin stands is divided ("split stream")

and each saw receives only one-half of the

cotton. The number of stages of saw cleaning

refers to the number of saws over which the

fibers pass.

LINT CLEANER WASTE

The amount of material removed by lint

cleaning depends on harvesting practices and

I 2 3

LINT-CLEANING STAGES

FIGURE 3-47.—Effect of saw lint cleaners on nep count,

yarn strengrth, and appearance.

grades of cotton being ginned. With multiple

stages of saw lint cleaners, the first cleaner

removes the most weight; the second, about

half as much as the first; and the third, about

half as much as the second. Typical quantities

of waste removed by one, two, and three lint

cleaners are 11, 18, and 22 pounds for cotton

graded as Strict Low Middling before cleaning;

corresponding weights are 19, 25, and 36

pounds for cotton classed as Strict Good

Ordinary.

Lint cleaners remove a greater percentage

of lint from the cleaner cottons. Nonlint content

of the lint-cleaner waste for one, two, and three

stages of lint cleaning averages about 75, 70,

and 67 percent. This material is composed of

motes, leaf particles, grass, bark, and green

leaves in varying amounts, depending on the

condition of the cotton.

The sale of reclaimed gin waste may provide

income for cotton-gin owners. The bedding,

automotive, and furniture industries use large

quantities of cotton batting composed of about

60 percent linters, and 40 percent cotton waste.

If waste materials must be cleaned to make

them marketable, and if the premium is less

than 1 cent, the weight loss in cleaning should

not exceed 20 percent of the original weight

(Holder 1967).

COTTON QUALITY

Perhaps the best index to cotton quality is

the performance of the fibers during spinning

at the mill. Increasing the number of saw lint

cleaners at the gin decreases the manufacturing

41
waste during spinning, but often has the adverse effect of increasing neps in the card

web and lowering the yarn strength and

appearance (fig. 3-47). A decline in appearance is greater for the finer carded yarns.

From a spinning standpoint, the use of more

than two saw lint cleaners in series is

discouraged.

BALE VALUE

Lint cleaning generally improves the grade

classification of the lint. As the number>of lint

cleaners increases, grade tends to increase.

However, each succeeding cleaner gives less

grade improvement than the preceding one. In

addition, lint cleaners blend Light-Spotted cottons so they pass into the White grades and

decrease the number of bales which are reduced

in grade because of the grass and bark content.

But when grades are improved, bale weights

are reduced and staple length may decrease;

and these opposing factors affect bale value

(fig. 3-48). In some cases the offsetting losses

cause the bale value to be reduced by lint

cleaning.

When price spreads between grades are small,

the grower can obtain maximum bale value

most often by using one saw lint cleaner on

early-season clean cottons and two stages of

lint cleaning on late-season, more trashy, or

Light-Spotted cottons. It is recommended that

no lint cleaning be used on cottons graded as

high as Middling White. Application of these

recommendations would depend on the ability

of the ginner to evaluate the type of cotton he

is processing.

OPERATION AND MAINTENANCE

The ginner and crew must know their machines—how they work and the required operating settings and speeds. For best performance

and service, the recommendations of the manufacturer as provided in service manuals and

parts catalogs should be carefully followed.

These provide maintenance procedures and

trouble-shooting guides, close adherence to

which will minimize the time required to keep

machines in normal operation. When in doubt

regarding appropriate action, contact the

manufacturer's nearest office.

Maintenance of the condenser will require

occasional replacement of the rubber flashing

around the drum and across doffing rollers.

The feed roller rubber flashing will wear and

LINT-CLEANING STAGES

FIGURE 3-48.—Effect of lint cleaners on classer's lint

grade and staple length, and bale weight and value.

should be replaced to prevent air leakage at

this point.

Maintain normal operating tension for V-belts

and chain drives. Do not forget the hidden

V-belt drive to the vane-axial fan in the condenser dust flue. When replacing badly worn

chains, it is good policy also to replace sprockets

on which they operate because their worn teeth

will not mate well with the new chain. Test

regularly for loosened set screws, bolts, and

jam nuts. Before tightening any bolt responsible for holding a clearance, gage and set the

clearance to comply with recommended

dimensions.

Most ball bearings are the sealed type and

are packed with high-temperature grease; they

should need no further lubrication for the life

of the bearing.

To start the lint-cleaning system, first turn

on the trash fan. Be sure the lint cleaner and

the condenser mounted on the lint cleaner are

in operation before energizing the vane-axial

fan in the receiving condenser dust flue. Shutdown of the lint-cleaning system should be in

reverse order, first stopping the flow of cotton

through the machinery. Always keep safety

guards and doors closed and fastened during

operation.

The sequence of the emergency stopping procedure depends entirely on the position of the

operator. If he is nearer the machine than the

control console, the belt release should be pulled

before the "stop'' button is pushed.

Any obstruction that will tag cotton should

be removed or smoothed. In flow-through air

42
cleaner installations, inspect each day for tags

in the lint flue between gin stand and lint

cleaner. Periodic inspection of saw cylinders

is urged. Should trash become embedded between teeth, remove it with a stiff brush (but

only when the machine is completely stopped).

Vane-axial fans should be kept free of lint tags,

which reduce fan efficiency and can cause

friction fires.

Following a regular service schedule based on

manufacturer's recommendations will enable

the ginner to keep his lint cleaner operating

efficiently with minimum overall maintenance.

REFERENCES

Griffin, A. C, and McCaskill, 0. L. 1957. Tandem lint

cleaning-air-saw cylinder combination. The Cotton

Gin and Oil Mill Press, March 23, 1957, pp. 25, 52-53.

Holder, S. H., Jr. 1967. Supply and price data on cotton

Packaging of Lint Cotton

By OLIVER L. MCCASKILL and W. STANLEY ANTHONY

Packaging is the final step in the processing

of lint cotton at the gin. The packaging system

consists of a lint condenser, lint slide, lint

feeder, tramper, bale press, and a strapping

subsystem. The bale press consists of a frame,

one or more rams, and a hydraulic system.

The strapping subsystem may be entirely

manual, semiautomated, or fully automated.

Bale presses are described primarily by the

density of the bale that they produce, such as

low, standard, or universal. There are other

descriptions, such as up-packing, down-packing.

gin motes. U.S. Dep. Agrie. Mark. Res. Rep. 809,

24 pp.

Looney, Z. M., LaPlue, L. D., Wilmot, C. A., and others.

1963. Multiple lint cleaning at cotton gins: effects

on bale value, fiber properties, and spinning performance. U.S. Dep. Agrie. Mark. Res. Rep. 601,

53 pp.

Mangialardi, G. J., Jr. 1970. Savir-cylinder lint cleaning

at cotton gins: effects of saw speed and combing

ratio on lint quality. U.S. Dep. Agrie. Tech. Bull.

1418, 73 pp.

. 1972. Multiple lint-cotton cleaning: its effect

on bale value, fiber quality, and waste composition.

U.S. Dep. Agrie. Tech. Bull. 1456, 69 pp.

St. Clair, J. S., and Roberts, A. L. 1958. Effects of lint

cleaning of cotton: an economic analysis at California gins. U.S. Dep. Agrie. Mark. Res. Rep. 238,

37 pp.

Stedronsky, V. L. 1964. Lint cleaning. U.S. Dep. Agrie.

Agrie. Handb. 260, pp. 32-45.

U.S. Agricultural Marketing Service. 1972. Cotton gin

equipment 1972, 16 pp.

fixed-box (fig. 3-49), and doorless presses

(fig. 3-50). Regardless of description, they all

accomplish the same thing—packaging lint cotton so that it can be handled in the channels of

trade.

BATTERY CONDENSER

Condensers employ a slow-turning, screened

drum on which the ginned lint forms into a

batt. The batt is discharged between doffing

rollers to the lint slide. Conveying air passes

through the screen on the drum and is usually

discharged out one end of the drum through

an air duct and into the atmosphere.

Most condensers employ a suction fan in the

air discharge line to overcome the static pressure loss in the system. This also makes it

PN-5235

FIGURE 3-49.—Fixed-box press with automatic

strapping.

PN-5236

FIGURE 3-50.—Doorless press with automatic strapping.

48
possible to handle more lint with a smaller

condenser and lint flue system.

The speed of the condenser drum should be

adjusted to the capacity of the gin so that a

smooth, solid batt is formed. If the drum runs

too fast, breaks will occur in the batt; if too

slow, the batt will be too thick, causing high

static pressure loss and possible chokage. The

recommended condenser drum speed is 6 to

15 revolutions per minute.

Uneven formation of the batt in the condenser is one of the primary causes of big-ended

bales (Watson and Stedronsky 1943). Bigended bales are formed when more lint is

deposited at one end of the press box than at

the other. During the pressing operation, the

increased density or weight at one end of the

bale forces the follow block into an inclined

position, thus forming wedge-shaped bales (fig.

3-51). Press hands may leave slack ties on the

light end of the bale, which prevents the uneven

weight from being apparent when the bale is

released from the press.

Some bales appear to be big-ended, although

they are not. For instance, a hydraulic ram

can slip after the bale is pressed and while

the ties are being applied. Between the time

the first and last ties are applied, the bale

becomes larger at one end than at the other.

The dangers of tramper breakage and press

distortion are great with uneven bales. A ginner

cannot afford to risk a broken ram or sprung

center column, particularly when uneven

packing can be eliminated.

The manner in which the lint is deposited on

the condenser drum can cause a big-ended bale.

Lint cotton is conveyed to the condenser from

the gin stands or lint cleaners by a continuous

air current. Any deviation in the airflow to the

condenser will automatically disrupt the flow

of the lint cotton. Lint flues that are bent and

battered can sometimes affect the flow of air

so that lint will not travel through them

uniformly.

Sheet-metal deflectors are used in lint flues

to provide uniform distribution of the lint on

the condenser drum to prevent or correct bigended bales. Foreign matter such as tags, rivet

heads, rust, or protrusions can often cause deflection of the air current, resulting in uneven

batts on the screen of the condenser.

Condensers in poor operating condition,

flashings in bad condition, and nonuniform

drum resistance may cause more cotton and air

to be deflected to one end of the drum and thus

produce big-ended bales. Daily inspection of

the condenser and its vent pipes is a good preventive measure and will reduce the number

of big-ended bales.

Battery condensers that discharge the conveying air from only one side are sensitive to

the volume of airflow. Excess airflow will cause

the batt to form on the drum nearest the air

discharge and cause a big-ended bale. This

problem can usually be corrected by reducing

the air volume; however, installation of a larger

condenser may be necessary. Use of a double

manifold condenser, similar to a lint cleaner

condenser, would be another way to correct

the problem of big-ended bales and, at the same

time, produce a more uniform batt of cotton

for the press.

LINT SLIDES

The lint slide is a sheet metal trough (approximately 54 inches wide) which connects

the battery condenser to the lint feeder on the

tramper. It is installed on an angle of 40° to

45° to insure movement of the lint. The length

of the lint slide is based on the capacity of the

ginning system and the time required to turn

the press between bales. The following is a

general guide for selecting lint slide lengths

based on ginning capacity:

MaxiTnum

ginning capacity

(bales¡hour)

6

12

18

24

30

Lint slide length

(feet)

10

12

14

16

18

LINT FEEDER

The lint feeder is a device for moving lint

from the lint slide into the charging box of the

press. There are four basic types of feeders:

(1) the revolving paddle kicker, (2) the belt

feed used in conjunction with the kicker,

(3) the lint pusher, and (4) the air-suction

feed.

All these devices are intended to deposit lint

into the charging box with a fast but gentle

action, without agitating, turning, rolling,

tumbling, tearing, or otherwise breaking up

the batt as it is received from the condenser.

44
PN-6237

FIGURE 3-51.—Big-ended or heavy-ended bale in a gin

press.

A smoother lint sample will result if this can

be accomplished.

Rolling bales are caused primarily by faulty

action of the kicker device (Watson and Stedronsky 1943). Proper adjustment of the kicker

speed and synchronization with the tramper

is necessary to achieve good results. The speed

or rate of sweep is the principal factor affecting the front-to-rear distribution of lint in the

press box. If the discharge is too strong, more

lint will be deposited in the front of the box

than in the rear. The reverse is true if the

discharge is too weak. Variations in tramper

speed seem to have little effect on uniformity

of bale layering. However, if the kicker is

driven from the tramper, a change in tramper

speed will affect unevenly packed bales because

of the change in kicker speed. Figure 3-52

shows an end view of a rolling bale.

Sometimes rolling bales are produced when

the lint slide is too short or has too much slope.

The lint slide shape can be adjusted to prevent

rolling bales. The ginner, however, is still responsible for making reasonable efforts to have

cotton delivered in an even flow into the gin

press box.

TRAMPER

The purpose of the tramper is to pack the

lint into the press box, thus putting it under

light compression. A good tramper combines

ruggedness with simplicity. It must be regulated to permit clearing the lint slide between

strokes. A kicker device deposits lint in the

PN-6238

FIGURE 3-52.—End view of rolling bale.

press box between strokes of the tramper. The

speed of the kicker is related to the time the

tramper is up, allowing cotton to be "kicked"

into the top of the press box.

Trampers are available in different types,

such as mechanical double-chain and hydraulic.

Regardless of type, care should be taken to

prevent contamination of lint beneath the

tramper by lubricants or hydraulic fluid that

might drip from the tramper mechanism.

Motors of 10 to 15 horsepower, equipped with

a fail-safe brake, are usually required for

trampers.

Approximately 10 tramper strokes per minute is a rate recommended for high-capacity

gins (12 to 15 bales per hour). For gins of

smaller capacity, the tramper speed should be

reduced proportionately. The tramper stroke

rate is governed by the ginning rate for a

particular gin. To determine the number, observe the cotton in the lint slide between

strokes. If the lint feeder cleans the slide for

each stroke, the number of strokes is correct.

However, if the storage space is filled between

the kicker and the front gate and the kicker

is carrying cotton around between strokes after

the space under the tramper block is filled, add

another stroke to the tramper by changing the

ratio of the tramper driving and driven

pulleys.

BALE PRESS

There are four types of gin presses that

produce bales of different sizes and densities—

flat, modified flat, gin standard, and gin uni45
TABLE 3-9.—Types and dimensions of the four

most common bales produced at cotton gins

^ , Bale dimensions (inches) Bale type Length Width^ Thicknessi

Flat 55 28 36-48

Modified flat 55 25 36-48

Gin standard 55 20-21 30-36

Gin universal 55 20-21 26-30

1 Measured at the bale tie.

TABLE 3-10.—Typical densities of bales from a flat-bale press^

Bale

dimensions- Volume Density (Ib/ft^) at bale weight of—

( inches) (ft^) 4601b 4801b 5001b 5201b 5401b 5601b

55X28X36 32.1 14.3 15.0 15.6 16.2 16.8 17.5

55X28X37 33.0 14.0 14.6 15.2 15.8 16.4 17.0

55X28X38 33.9 13.6 14.2 14.8 15.4 15.9 16.5

55X28X39 34.8 13.2 13.8 14.4 15.0 15.5 16.1

55X28X40 35.6 12.9 13.5 14.0 14.6 15.1 15.7

55X28X41 36.5 12.6 13.1 13.7 14.2 14.8 15.3

55X28X42 37.4 12.3 12.8 13.4 13.9 14.4 15.0

55X28X43 38.3 12.0 12.5 13.0 13.6 14.1 14.6

55X28X44 39.2 11.7 12.2 12.8 13.3 13.8 14.3

55X28X45 40.1 11.5 12.0 12.5 13.0 13.5 14.0

55X28X46 41.0 11.2 11.7 12.2 12.7 13.2 13.7

55X28X47 41.9 11.0 11.5 11.9 12.4 12.9 13.4

55X28X48 42.8 10.8 11.2 11.7 12.2 12.6 13.1

1 Press box area: 54"X27" = 1,458 in2.

'^ Width and thickness measured at the bale tie.

TABLE 3-11.—Typical densities of bales from a modified flat-bale press^

Bale

dimensions'-

(inch)

Volume

(ft3)

Density (Ib/ft^) at bale weight of—

4601b 4801b 5001b 5201b 5401b 5601b

55X25X36 28.6 16.1 16.8 17.5 18.2 18.9 19.1

55X25X37 29.4 15.6 16.3 17.0 17.7 18.3 19.0

55X25X38 30.2 15.2 15.9 16.5 17.2 17.9 18.5

55X25X39 31.0 14.8 15.5 16.1 16.8 17.4 18.0

55X25X40 31.8 14.5 15.1 15.7 16.3 17.0 17.6

55X25X41 32.6 14.1 14.7 15.3 15.9 16.6 17.2

55X25X42 33.4 13.8 14.4 15.0 15.6 16.2 16.8

55X25X43 34.2 13.4 14.0 14.6 15.2 15.8 16.4

55X25X44 35.0 13.1 13.7 14.3 14.9 15.4 16.0

55X25X45 35.8 12.8 13.4 14.0 14.5 15.1 15.6

55X25X46 36.6 12.6 13.1 13.7 14.2 14.8 15.3

55X25X47 37.4 12.3 12.8 13.4 13.9 14.4 15.0

55X25X48 38.2 12.0 12.6 13.1 13.6 14.1 14.7

1 Press box area : 54" X 24" = 1,296 in2.

- Width and thickness measured at the bale tie.

46
TABLE S-12.—Typical densities of bales from standard- and universaldensity presses^

Bale

dimensions^ Volume

(ft»)

Density (lb/ft») at bale-weight of—

(inches) 4601b 4801b 500 1b 520 1b 5401b 5601b

55X20X25 15.9 28.9 30.2 31.4 32.7 33.9 35.2

»55X20X26 16.6 27.8 29.0 30.2 31.4 32.6 33.8

•'55X20X27 17.2 26.8 27.9 29.1 30.3 31.4 32.5

•'55X20X28 17.8 25.8 26.9 28.1 29.2 30.3 31.4

55X20X29 18.5 24.9 26.0 27.1 28.2 29.3 30.3

"55X20X30 19.1 24.1 25.1 26.2 27.2 28.3 29.3

"55X20X31 19.7 23.3 24.3 25.3 26.4 27.4 28.4

^55X20X32 20.4 22.6 23.6 24.5 25.5 26.5 27.5

55X20X33 21.0 21.9 22.8 23.8 24.8 25.7 26.7

55X20X34 21.6 21.3 22.2 23.1 24.0 24.9 25.9

55X20X35 22.3 20.6 21.5 22.4 23.3 24.2 25.1

55X20X36 22.9 20.1 20.9 21.8 22.7 23.6 24.4

55X21X25 16.7 27.5 28.7 29.9 31.1 32.3 33.5

■■'55X21X26 17.4 26.5 27.6 28.8 29.9 31.1 32.2

»55X21X27 18.0 25.5 26.6 27.7 28.8 29.9 31.0

'55X21X28 18.7 24.6 25.6 26.7 27.8 28.9 29.9

55X21X29 19.4 23.7 24.8 25.8 26.8 27.9 28.9

"55X21X30 20.1 22.9 23.9 24.9 25.9 26.9 27.9

"55X21X31 20.7 22.2 23.2 24.1 25.1 26.1 27.0

"55X21X32 21.4 21.5 22.4 23.4 24.3 25.2 26.2

55X21X33 22.1 20.9 21.8 22.7 23.6 24.5 25.4

55X21X34 22.7 20.2 21.1 22.0 22.9 23.8 24.6

55X21X35 23.4 19.7 20.5 21.4 22.2 23.1 23.9

55X21X36 24.1 19.1 19.9 20.8 21.6 22.4 23.3

1 Press box area: 54 in X 20 in =1,080 in2.

-' Width and thickness at the bale tie.

' Suggested universal-density bale size.

' Suggested standard-density bale size.

versal (table 3-9). The theoretical densities

in bales produced by these presses are shown

in tables 3-10, 3-11, and 3-12.

Flat-bale presses are being phased out in

favor of modified flat-bale presses so that a

universal bale (55 by 25 by 21 inches) can be

made at the compress without applying side

pressure to the bale, A flat-bale press (27 by

54 inches) can be easily converted to a modified

flat press (24 by 54 inches) (National Cotton

Council 1972).

Steps in modifying a flat-bale press are as

follows:

1. The 3-inch reduction in box width can

be obtained by bolting finished 2-inch by 6- or

8-inch lumber to the inside walls. Use C-grade

kiln-dried pine or clear-grade oak with a finished thickness of IV2 inches. Check dimensions

for dog spacing and press box construction in

order to purchase lumber most economically.

2. Bolt each board to side walls with two

cadmium-plated, %-inch carriage bolts near

both ends of each board. Notch board to allow

clearance for dogs. Extend dog slots downward

if necessary to clear the extended dogs (fig.

3-53).

3. Lengthen dogs I14 inches to maintain

original penetration into the box by welding

FIGURE 3-53.—Modified flat-bale press box.

47
metal of the same thickness to end of dogs and

grinding smooth.

4. Reduce both follow blocks 3 inches in

width by cutting IV2 inches off each end of

cross channels. Re-cover channel ends with

metal to keep bale strap guides intact, and reduce bagging retainer loops on the platen by

V/2 inches on each side (fig. 3-54).

5. Reduce tramper box by 3 inches. Where

possible, cut tramper platen width l^A inches

on each side. In some models, the full 3 inches

may have to be removed from the front side

of the platen and the whole tramper moved

IV2 inches forward in order to stay on center

with the press box. Make a thorougk study of

your particular press to see exactly what pieces

will have to be cut or moved to maintain proper

clearances.

Existing hydraulic and mechanical press

equipment should have sufficient strength if

the bales are tied out 3 to 5 inches thicker. If

there is any doubt that any part of the tramper

or press should be strengthened structurally or

horsepower increased, it is suggested that the

original manufacturer of the units be consulted. This is especially important on some

models of down-packing presses with short

boxes.

PN 5240

FIGURE 3-54.—Modified flat-bale press follow block.

TABLE 3-13.—Densities produced by pressing

in flat-bale presses^

TABLE 3-14.—Densities produced by pressing

in a modified flat-bale press^

Platen

separation

(inches)

Density in press (Ib/ft^) at bale weight of—

4601b 4801b 5001b 5201b 5401b 5601b

26 23.6 24.6 25.6 26.7 27.7 28.7

27 22.7 23.7 24.7 25.7 26.7 27.7

28 21.9 22.9 23.8 24.8 25.7 26.7

29 21.1 22.1 23.0 23.9 24.8 25.7

30 20.4 21.3 22.2 23.1 24.0 24.9

31 19.8 20.6 21.5 22.4 23.2 24.1

32 19.2 20.0 20.8 21.7 22.5 23.3

33 18.6 19.4 20.2 21.0 21.8 22.6

34 18.0 18.8 19.6 20.4 21.2 22.0

35 17.5 18.3 19.0 19.8 20.6 21.3

36 17.0 17.8 18.5 19.3 20.0 20.7

37 16.6 17.3 18.0 18.7 19.5 20.2

38 16.1 16.8 17.5 18.2 18.9 19.6

1 Press box area of 1,296 in=.

TABLE 3-15.—Densities produced by pressing

Platen Density

4601b

in press (Ib/ff) at bale weight of—

4801b 5001b 5201b 5401b 560 1b

separation

(inches)

Platen

separation

(inches)

Density

4601b

in press (lb/ft-') at bale weight of—

4801b 5001b 5201b 5401b 5601b

26 21.0 21 9 22 8 23 7 24 6 25 5

27 20.2 21.1 21.9 22.8 23.7 24.6 17 43.3 45.2 47.1 48.9 50.8 52.7

28 19.5 20.3 21.2 22.0 22.9 23.7 18 40.9 42.7 44.4 46.2 48.0 49.8

29 18.8 19.6 20.4 21.3 22.1 22.9 19 38.7 40.4 42.1 43.8 45.5 47.2

30 18.2 19.0 19.8 20.5 21.3 22.1 20 36.8 38.4 40.0 41.6 43.2 44.8

31 17.6 18.4 19.1 19.9 20.6 21.4 21 35.0 36.6 38.1 39.6 41.1 42.7

32 17.0 17.8 18.5 19.3 20.6 20.7 22 33.5 34.9 36.4 37.8 39.3 40.7

33 16.5 17.2 18.0 18.7 19.4 20.1 23 32.0 33.4 34.8 36.2 37.6 39.0

34 16.0 16.7 17.4 18.1 18.8 19.5 24 30.7 32.0 33.3 34.7 36.0 37.3

35 15.6 16.3 16.9 17.6 18.3 19.0 25 29.4 30.7 32.0 33.3 34.6 35.8

36 15.1 15.8 16.5 17.1 17.8 18.4 26 28.3 29.5 30.8 32.0 33.2 34.5

37 14.7 15.4 16.0 16.7 17.3 17.9 27 27.3 28.4 29.6 30.8 32.0 33.2

38 14.3 15.0 15.6 16.2 16.8 17.5 28 26.3 27.4 28.6 29.7 30.9 32.0

1 Press box area of 1,458 in^. 1 Press box area of 1,080 in^.

48
The long-range goal is to have only two types

of bales produced at the gin—gin universal

and modified flat, which is recompressed at

the compress to universal density.

HYDRAULICS

The hydraulic requirement to press lint cotton depends on the moisture content of the lint

and the density to which it is to be pressed

(Anthony and McCaskill 1973). Typical densities encountered when pressing flat, modified

flat, and standard or universal bales are shown

in tables 3-13, 3-14, and 3-15, respectively.

The force required to compress lint cotton

to given densities at various moisture contents

may be predicted from the equation

log F=2.0929-0.0313M + 2.4469 log^^ P,

where F=compressive force, pounds,

M=lint moisture content (wet basis),

percent,

and /3=density, pound per cubic foot.

The results of evaluating the prediction

equation are shown in figure 3-55 for a density

range of 10 to 45 pounds per cubic foot and

lint moisture content of 3, 6, and 9 percent.

Extrapolation beyond these values cannot be

supported by research data at this time.

The theoretical force available from selected

single-acting hydraulic cylinders is shown in

table 3-16. The hydraulic requirement can be

determined from these tables for almost any

bale press.

tent in a modified flat press to a platen

separation of 37 inches in 25 seconds.

Assume a ram travel of 7 feet and

hydraulic pressure not to exceed 2,800

pounds per square inch gage.

SOLUTION: Table 3-14 indicates that a density of

18.0 pounds per cubic foot would result

in a modified flat press box at a platen

separation of 37 inches for a 500-pound

bale. Figure 3-55 indicates that lint

cotton at 3-percent moisture would require approximately 120,000 pounds of

force for compression to 18.0 pounds per

10

O

1500

1000

~i

:i:-:::::: ::::i!

'

700

: =zzZZ. z: zz:

— !!:=::::;; i:^!!! —' —1 — — — ::.z:"[, ' ;''

400 "" ?':';'

.4..I./. ^ / /

/ //

200 'iI ^' 7

¿JE 5 ^J IÍ '

150

100

70

yfflS iS

¿m^

=,= :::=

^

^

2

rynl

—1 — —

— — 2 /jZM^U4^.UA^i>u ' ';.'k'; u:;'

á ^ ^ T? Ti M 1 /,/^ / 1II111111 'i LLU ' M "11 Mill

40 1 1 1 1 1 M IZ.44b!# laOKIIIIII ^ / / 1 1 1 1111 1 "

/

y /

y y

20

15

/

>

10 15 20 25 30 35 40 45

DENSITY, LB/FT'

EXAMPLE: Determine the diameter of ram and

hydraulic requirement to compress 500 FIGURE 3-55 .—Predicted force to compress lint cotton

pounds of lint at 3-percent moisture con- to give densities at three moisture contents.

TABLE 3--16.—The theoretical force available from selected! single-acting hydraulic cylinders

Cylinder

Oil

requirement

per foot of

Theoretical force (lb) at hydraulic pressure of—

diameter 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000 (inches) stroke (gal) lb/in2g lb/in2g lb/in2g lb/in2g lb/in2g lb/in2g lb/in2g lb/in2g

8% 2.9 82,633 110,177 137,721 165,265 192,809 220,353 247,897 275,442

9 3.3 95,426 127,235 159,043 190,852 222,660 254,469 286,278 318,086

10 4.1 117,810 157,080 196,350 235,619 274,890 314,159 353,429 392,699

11 4.9 142,550 190,066 237,583 285,100 332,616 380,133 427,649 475,166

12 5.9 169,646 226,195 282,743 339,292 395,841 452,389 508,938 565,487

13 6.9 199,095 265,460 331,825 398,190 464,555 530,920 597,285 663,650

14 8.0 230,907 307,876 384,845 461,814 538,783 615,752 692,721 769,690

15 9.2 265,072 353,429 441,787 530,144 618,501 706,858 795,216 883,573

16 10.4 301,593 402,124 502,655 603,186 703,717 804,248 904,779 1,005,310

17 11.8 340,470 453,960 567,450 680,940 794,430 907,920 1,021,410 1,134,900

17% 12.3 355,657 474,209 592,761 711,313 829,865 948,417 1,066,970 1,185,522

49
cubic foot density. From table 3-16 we

find that an 8 %-inch-diameter ram will

develop 137,721 pounds of theoretical

force at 2,500 pounds per square inch

gage. Also from table 3-16 we find that

an 8 % -inch-diameter ram would require

2.9 gallons of oil per foot of stroke.

The quantity of oil required per 7-foot

stroke would be 2.9x7 =20.3 gallons.

The hydraulic pump requirement can

be determined by multiplying the oil

required per stroke by the time in minutes—20.3 X (60/25) =48.7 gallons per

minute; therefore, a 49-gallon-perminute pump would be required to raise

the ram in 25 seconds.

Another approach to determine the hydraulic

capability for packaging lint cotton is to pick

a ram size and determine the bale size that can

be produced in a specific type of press. For

multiple-ram presses, multiply the theoretical

force and oil requirements in table 3-16 by

the number of rams.

EXAMPLE : Determine the capability of a universalbale press having two 14-inch-diameter

rams with a 7^-foot stroke required to

obtain a 20-inch platen separation, and

a 360-gallon-per-minute hydraulic system that is set to unload at 3,500 pounds

per square inch gage.

SOLUTION: From table 3-16 we find that two 14-

inch-diameter rams will deliver 1,077,566

pounds of force at 3,500 pounds per

square inch gage. From figure 3-55 we

find that lint cotton at 3-percent lint

moisture can be compressed to a density

of 45 pounds per cubic foot with that

force. Referring now to table 3-15 we

can determine the capabilities of the

press. This press is capable of pressing a

560-pound bale to a platen separation of

20 inches. The time required for ram

travel can be determined by multiplying

the quantity of oil required per foot of

stroke (from table 3-16) by the length

of stroke and dividing by the pump

capacity.

(2) (8 gal/ft) (7.5 ft)

360 gal/min

= 0.33 min or (0.33) (60) =20 seconds

The final bale size/after it is released

from the press, will depend upon the

bale-restraining material.

Hydraulic systems should be designed to meet

the most adverse conditions anticipated, which

would be the heaviest bale at the lowest moisture content and packaged at the smallest size

desired.

BALE TIES

After the bale is compressed to a given density, bale ties are applied around the circumference of the bale to restrain the lint cotton

within certain dimensions. Bale ties are normally flat metal bands, either hot- or cold-rolled

steel, or wire, and are placed at intervals along

the length of the bale. Usually, six, eight or

nine ties per bale are used. The resilient force

of the lint cotton produces a resulting force

on the bale ties, which is a function of the

density to which the bale is compressed before

it is released from the press, the density at

which it is restrained after it is released from

the press, and the moisture content of the lint

cotton.

The difficulties encountered in calculating

the true densities involved in packaging lint

cotton necessitate the use of more easily obtainable variables. The factor "density compressed

to*' can be replaced by using the platen separaTABLE 3~17.—Approximate bale circumferences

for bales packaged in gin presses'^

Press box Bale Bale Tie

dimensions2 width thickness length

(inches) (inches)

28

(inches) (inches)

36 110.0

28 38 114.0

28 40 118.0

27X54 28 42 122.0

28 44 126.0

28 46 130.0

28 48 134.0

25 36 107.0

25 38 111.0

25 40 115.0

24X54 25 42 19.0

25 44 123.0

25 46 127.0

i 25 48 131.0

f 21 26 84.0

21 28 88.0

21 30 92.0

21 32 96.0

21 34 100.0

20X54 i 20 26 82.5

20 28 86.5

20 30 90.5

20 32 94.5

^ 20 34 98.5

1 Length and thickness measurements were made at

the ties.

2 Dimensions are approximate.

50
tion to which the bale is compressed, the quantity of cotton in the bale, and the cross-sectional

area of the press. For a given bale weight in a

particular press, the platen separation alone

may be used. The factor "density restrained

at^' may be replaced by the quantity of cotton

in the bale, the bale cross-sectional area, and

the bale circumference. For a given bale weight

produced in a particular press, the bale

circumference alone can be used.

Typical bale circumference for gin-packaging

systems are given in table 3-17.

Experimental work at the U.S. Cotton Ginning Research Laboratory at Stoneville, Miss.,

has related the bale tie force to the final platen

separation pressed to, the bale circumference

(measured at the tie), and the lint moisture

content. The force on the ties has been found

to be different for each of the six to nine ties.

The bale tie with the highest force exerted on

it has been found to represent 15 to 20 percent

of the total force exerted on all the ties of a

bale. The bale tie force distribution for one gin

universal bale press is shown in figure 3-56.

The force per tie has been found to range

from less than 100 to more than 4,000 pounds.

Flat and modified flat bales are normally packaged with six steel bands having a tensile

strength of 2,500 to 2,800 pounds or wire having a strength of 3,400 pounds. Gin standard

bales are normally packaged with eight steel

bands having a tensile strength of 2,500 to 2,800

pounds and special buckles or wire having a

tensile strength of 3,400 pounds. Gin universal

bales are normally packaged with eight flat,

cold-rolled steel bands having a tensile strength

in excess of 4,000 pounds.

The relationship between the maximum force

per tie, the platen separation to which a bale

is pressed before applying the ties, and the

bale circumference at the tie after the bale is

released from the press is shown in figure 3-57

for 500-pound bales at 5-percent lint moisture

packaged in a gin universal press.

EXAMPLE : Determine the maximum tie force

exerted on oVie of eight equally spaced

bale ties on a 500-pound bale at 5-percent lint moisture packaged in a gin

universal press. The bale circumference

at the tie is 85 inches.

SOLUTION: Refer to figure 3-57 and note that

3,000 pounds of force is exerted when

the bale is compressed to a platen separation of 21 inches and 2,050 pounds

when the bale is compressed to 19 inches.

A change in platen separation of only 2

inches resulted in a 32-percent reduction in bale

tie force.

Variation in the bale circumference also has

a pronounced effect on bale tie force. When

a 500-pound bale at 5-percent lint moisture is

compressed to a platen separation of 19 inches

4.000

3.000

2

3

2

X

<

2

2.000

1,500

1.000

700

500

400

300

200

150

r 1II111

^

S--S—s

I -s;:^s '^::

^ÊÊEllsÊh=i3^^4_:zir = i

-iüniüS^^ 1 j

_Nr* ^

IJX^ \p Xj^ ^^' '

l}^ \ xl" V^

- : :4^ >jj.\^\

S^o NáL \| S^

L>?'^ v.. A \

\<^ ^. ^ : ^ "

\i 5 ^^ ÜJ. S ^

M\ M- S- ^^s^ "^

10.5484 logC + 3.76 67PS S S

R^ • 0.96 \ ^

F - Bale tie force

C • Sale tie circumferenc e

PS - Platen separation

[

L^ -

2 3 4 5 6 7 8

BALE TIE POSITION

FIGURE 3-56.—Bale tie force distribution for one gin

universal bale press.

81 85 89 93 97 101 105

BALE CIRCUMFERENCE. INCHES

FIGURE 3-57.—Maximum tie force per tie exerted by

500-pound bales of Upland cotton at 5-percent lint

moisture content.

51
in a gin universal press, a maximum tie force

of 2,350 or 1,650 pounds results, depending on

whether restrained bale circumference is 84

or 88 inches, respectively (fig. 3-57). A change

in bale circumference of only 4 inches resulted

in a 30-percent reduction in bale tie force. Note

that 4 inches of bale circumference produces

a 2-inch change in bale thickness (table 3-17).

The maximum tie forces exerted by bales

produced in flat and modified flat presses vary

in much the same manner as in gin universal

presses, although the forces involved are lower.

The maximum tie force exerted by bales can

be reduced by uniform distribution of the lint

cotton in the press box. When the lint cotton

is very unevenly distributed in the press box,

one tie may have 300 percent more force

exerted on it than another tie on the same bale.

The force used to compress lint cotton and

the tensile strength of the bale ties used to

restrain lint cotton can be varied to compensate

for low moisture or large bales.

Special care must be taken to insure that the

bale ties are not overstressed. Broken bale ties

can be quite expensive to replace since the bale

must be repressed before a new tie can be

applied.

REFERENCES

National Cotton Council, Universal Bale Committee.

1972. A universal bale for universal benefits, 7 pp.

Anthony, S., and McCaskill, 0. L. 1973. Forces involved

in packaging lint cotton. The Cotton Gin and Oil Mill

Press 74(15): 7-11.

Watson, L. J., and Stedronsky, V. L. 1943. Packing of

cotton at gins for uniform density. U.S. Dep. Agrie.

Misc. Pub. 527, 22 pp.

52
SECTION 4.-MATERIALS HANDLING

Separators and Droppers

By T. E. WRIGHT

The main function of the separator in the

gin outfit is to separate the seed cotton from

the conveying air. The separator is usually the

first machine in the ginning process to receive

FIGURE 4-1.—Separator with multiple screen sections

and cylinders (Bush-Hog/Continental Gin).

seed cotton and is subjected to the most severe

operating conditions of uneven material flow

and negative (suction) pressure. High-capacity

ginning has made the operating conditions more

severe and has brought about heavier and

tighter construction in separator design.

Separators of present manufacture are of

four basic types: (1) those in which the main

flow of seed cotton does not come in contact

with a stationary screen and in which the

screen is cleaned by rubber wiper flights attached to a revolving reel or cleaner-type cylinders (figs. 4-1—4-3); (2) those in which the

seed cotton is directed onto a stationary screen

and in which the screen is kept clean by rubber

wiper flashing attached to a revolving reel

(fig. 4-4) ; (3) those in which the seed cotton

is directed over and around a revolving screen

drum and in which the screen is kept clean by

centrifugal force of the rotating drum (fig.

4-5); and (4) those in which the seed cotton

is directed diagonally onto a stationary gridbar screen and in which the screen is cleaned

by the wiping action of the incoming seed

cotton and air (fig. 4-6).

The first and second types of separators have

FIGURE 4-2.—Separator with multiple screen sections

and cylinders (Murray-Piratininga).

FIGURE 4-3.—Separator with reversed curved screen

and revolving reel (Hardwicke-Etter).

53
FIGURE 4-4.—Separator with curved screen and

revolving reel (Lummus).

rubber wipers on the rotating member or members. These wipers, which clean the screen,

require little maintenance unless they are subjected to high temperature, as is the case when

the separator is used as the I'eceiving unit in

the drying system. However, the wipers should

be inspected periodically for wear and damage.

The wipers are made with slotted fastening

holes and can be adjusted to the screen as wear

occurs. If the wipers have become set in a

cupped position away from the screen, they can

sometimes be removed and turned over to give

further service. Excessively worn and broken

wipers should be replaced.

The upper section of the third type of separator requires little maintenance other than

periodic inspection of the seal flashing to see

if it is sealing the ends of the screen drum

properly. Worn or damaged flashing should be

replaced.

The maintenance required for the upper section of the fourth type of separator is mainly

periodic inspection to see if the grid-bar section

is being properly cleaned by the wiping action

of the incoming seed cotton and air. Spread of

seed cotton over the entire width of the screen

is important and is obtained by adjusting a

dovetail spreader in the inlet transmission. The

grid-bar screen should be adjusted so that the

ends of the grid bars clear the back baffle by

approximately 2 inches.

The rubber flights in the lower, or vacuum,

section of all separators require more attention

and more frequent adjustment or replacement

than do the rubber wipers in the upper screen

FIGURE 4-5.—Separator with revolving screen drum

(Bush-Hog/Continental Gin).

FIGURE 4-6.—Separator with curved grid-bar screen

(Kimbell-Bishard).

54
section of the separator. To minimize air leakage into or out of the separator, these flights

must be maintained in proper adjustment and

good condition. When separation choking

occurs, it is usually because the flights have

become so worn and damaged that they are

not properly sealing against the side scrolls.

Under this condition, the air leakage passing

the flights may cause an updraft of sufficient

force to float the seed cotton in the upper

section and prevent it from discharging through

the vacuum section.

Vacuum wheels, or droppers, are used in the

gin outfit to meter seed cotton, seed, and trash

into a conveying airstream. They are also used

as a sealer to prevent escape of air while the

seed cotton or seed is metered from an airstream into an **out of line" type of gin machine.

A typical seed-cotton dropper is shown in

figure 4-7; most droppers are identical in construction and maintenance requirements to the

lower or vacuum section of the separator. When

adjusting or installing flights, the manufacturer's instructions should be followed carefully. Generally, flights should be set so that the

edges rub securely against the side scrolls. They

should be set out sufficiently so that when

they pass the side scroll they will bend approximately one-half inch and not more than threefourths inch from a straight line. They should

not be required to bend or flex unduly. When

the rubber flights are checked or replaced, the

rubber flashings or wipers on the ends of the

vacuum cylinder should also be inspected and

replaced if they are damaged or worn. Some

of the latest models of seed-cotton droppers

have quick-change rubber flights that make

repair and maintenance quick and easy. Most

new drying systems incorporate a deflector

dropper, commonly called a flight-saver, between the seed-cotton dropper and the hot-air

stream. The flight-saver deflects most of the

hot air away from the seed-cotton dropper,

lengthening the life of the rubber flight. Seedcotton droppers used in the drying system

should be equipped with heat-resistant flights.

Trash and seed droppers are smaller in diFiGURE 4-7.—Seed-cotton vacuum-wheel dropper.

FIGURE 4-8.—Trash vacuum-wheel dropper. FIGURE 4-9.—Cottonseed vacuum-wheel dropper.

55
TABLE 4-1.—Capacities and power requirements for various sizes of separators and droppers^

Inside Dropper Motor Dropper

Machine width diameter Recommended required speed

(inches) (inches) capacity- ^j^pj (r/min)

Separators 72 22% 1-8 b/h 10 65/70

Do3 72 22% 8-16 b/h 15 65/70

Do3 72 34 16-24 b/h 20 65/70

Do3 96 34 24-35 b/h 25 65/70

Seed-cotton dropper ■■ 72 22% 8-16 b/h 10 65/70

Do 72 34 16-24 b/h 15 65/70

Do 96 34 24-35 b/h 20 65/70

Seed droppers 12 16 235 Ib/min 1 50/55

Do 18 16 352 Ib/min 2 50/55

Do 24 16 470 Ib/min 3 50/55

Trash droppers 12 16 120 Ib/min 1 50/55

Do 18 16 180 Ib/min 2 50/55

Do 24 16 240 Ib/min 3 50/55

1 Courtesy of Lummus Industries, Inc., Columbus, Ga.

- b/h = bales per hour.

■■' When used as live overflow separator, only 10-hp motor required.

ameter and length than seed-cotton droppers.

The typical trash (figs. 4-8) and seed (fig.

4-9) droppers are of the same basic design;

the main difference is that the seed dropper

has more flights than the trash dropper. The

additional flights are necessary to obtain sufficient sealing power for feeding into highpressure seed lines. Trash and seed are very

abrasive, and the flights in these droppers

will require more frequent inspection and

maintenance than those of the seed-cotton

dropper.

A special type of seed dropper (fig. 4-10)

is being used in some modern high-capacity gin

plants. This dropper has a close-fitting, allsteel, eight-blade rotor or wheel, which requires

no flexible flights or flashing. It operates very

efficiently in high-pressure seed systems using

positive-pressure blowers.

Capacity and power requirements for various

sizes of separators and droppers manufactured

by one of the major gin machinery companies

are given in table 4-1. These data are averages

and will vary considerably for different types

of cotton. The manufacturer should always be

consulted in making capacity and power

estimates for separators and droppers.

Separators and droppers used in gin pneuFlGURE 4-10.—Cottonseed vacuum-wheel dropper with

close fitting, all-steel, eight-blade rotor.

matic systems may constitute a major source

of power waste. Continuous upkeep, inspection,

and repair are necessary to reduce air leakage.

Even new and well-sealed separators have a

significant intake and leakage of air through

the vacuum dropper section: a 35-percent loss

at the separator is not uncommon. A periodic

check of all separators and droppers will greatly reduce downtime from chokages caused by

improper settings or worn parts in the

separator or dropper.

56
Fans and Piping

By OLIVER L. MCCASKILL, R. V. BAKER, and

V. L. STEDRONSKY

Pneumatic systems consume from 40 to 60

percent of the total power required in a modern

cotton gin. These systems are used to convey

seed cotton from truck, trailer, or storage;

operate cotton conditioners or driers; supply air

to the doffing nozzles of airblast gins; convey

cotton from point to point in the ginning

system; and convey seed, hulls, and trash.

AIR FACTS GINNERS SHOULD KNOW

There are a few major definitions and facts

that a ginner should keep in mind when dealing

with pneumatic handling systems, in order to

conserve power and keep them operating

properly.

1. **Static'' or resistance pressure in piping

systems corresponds to blood pressure in the

human body. "Velocity" pressure in piping

systems is like the heartbeat that causes blood

to flow; it conveys the material in a pipe.

Static pressure plus velocity pressure make

up the total pressure against which a fan must

operate.

2. Few open-wheel cotton gin fans have an

efficiency greater than 50 percent. Remberttype fans, with perforated disks that close

the wheel, have approximately 35 percent

efficiency.

3. Where pipe lengths are equal and where

equal flow of air is handled, smaller pipes

require more power and cause greater friction

resistance or static pressure than do larger

pipes (fig. 4-11). Table 4-2 shows the

equivalent straight-pipe resistance for 90°

elbows.

TABLE 4-2.—Resistance of 90''

duct) ^

elbows {round

Throat radius of elbow

in pipe diameters %

Diameters ofstraight pipe

offering equivalent

resistance 17

% 1 1% 11/2

14 12 11 9.7 8.5 6.5

1 For bends of less than 90° the equivalent resistance

is in proportion to the arc. For example, a 60° bend will

have % the equivalent resistance.

Example: A 90° elbow in 24-inch round pipe with a

24-inch throat radius will have the equivalent of 12

diameters, or 24 feet, of straight duct.

4. Piping velocities for handling dry seed

cotton should be held below 4,500 feet per

minute to avoid cracking or shattering seed

where the material hits fan disks, sharp-turn

elbows, separator reels, and other objects

(table 4-3).

5. Airflow calculations should include leakage as well as flow in pipes. Up to 30 percent

leakage in the vacuum wheel of the separator

must be allowed for at the fan. Tower driers

also frequently leak, and stopping air leaks

often saves money for gin owners.

6. Normal operating speeds vary, usually

from 1,400 revolutions per minute to 3,000

revolutions per minute, but for safety the tip

speed of the wheel should not exceed 18,000

feet per minute. Forward-pitch fan wheels are

sensitive to speed changes and therefore usually

waste more power than do straight-blade

wheels. Dampers should be provided on the

intakes of airblast fans (fig. 4-12). By use of

slides or other good dampers on fan intakes,

a substantial saving in power consumption is

often possible. Cutting holes in pipes to relieve

.01 .02 .03 .04 .06 .Oe .1 .8 .3 .4 .«.8 1 Z 9 4 • 6 10

FRICTION LOSS IN MCHES OF WATER* PER 100 FT

FIGURE 4-11.—Friction loss in round pipe per 100 feet

of length.

57
pressures or to increase airflow is usually

unsatisfactory.

Large-diameter fan wheels operating at low

speeds are generally more efficient and produce

less noise than small-diameter fan wheels at

high speeds. Since cotton-gin fan casings have

a large clearance, it is possible to adapt three

sizes of wheels to the fan, namely, an oversize,

a standard, or an undersize wheel. Thus a

No. 40 fan can be converted to a No. 35-40

or No. 40-45 fan by changing the wheel. The

true size of any fan is the size of its wheel.

PIPING

A practical pneumatic system must convey

material efficiently from point to point. In

cotton gins air is directed through pipes that

vary in diameter from 6 to 36 inches, made of

galvanized iron sheet from 24 to 36 gage. Piping systems are an important part of the gin

and should be carefully planned and maintained.

Some good rules to follow are:

TABLE 4-3.—Volume of airfloiv rate in various

sizes of pipe based on mean linear velocity

of Uy500 feet per minute

Pipe dimensions

Diameter

(inches)

Areal (ft^)

Volume

flow rate-

(ftVmin)

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

24

26

28

30

0.136

.196

.267

.349

.442

.545

.660

.785

.922

1.069

1.227

1.396

1.576

1.767

1.969

2.182

2.405

2.640

3.142

3.687

4.276

4.909

614

884

1,203

1,571

1,988

2,454

2,970

3,534

4,148

4,811

5,522

6,283

7,093

7,952

8,860

9,817

10,824

11,879

14,137

16,591

19,242

22,089

1. Make the piping as simple and direct as

possible, eliminating unnecessary elbows and

valves.

2. Keep all joints airtight and rigid to

prevent air leakage. This saves horsepower.

3. For good suction in seed-cotton pipe,

maintain velocities of 4,000 to 5,000 feet per

minute. Telescope diameters are usually 12 to

24 inches, depending on the seed-cotton requirements of the ginning system.

4. For conveying trash, keep the pipe diameter between 8 and 16 inches, and for seed,

between 10 and 13 inches. The velocity in the

pipe should be about 4,500 feet per minute

for seed cotton or trash, and at least 5,300 feet

per minute for seed. (This rule does not apply

to small-pipe seed-blowing systems where the

velocity is held to approximately 4,500 feet per

minute, while the pressure is, greatly increased

and the volume of air is reduced.)

5. Do not allow piping for cottonseed or

seed cotton to slope downward in the direction

of flow; downward slopes may cause chokages.

6. A Rembert-type fan is simple and economical for handling seed cotton in storagehouse operations. However, a standard

separator and fan system with well-designed

piping is more efficient and provides greater

capacity than the Rembert-type fan system.

7. Approximately 20 cubic feet of air per

pound of material should be sufficient for

series fans on the unloading system and pushpull fans on the drying systems. This volume

will vary depending on static pressure demands

on the fan.

Air velocities required for efficient conveying

of the materials handled at gins are:

lArea Area Yft2) (it ) =-^^^^ = M^M^ ^^ where

inches and cZ = diameter in inches.

2 Volume flow rate (ftVmin) =4,500Xarea

radius in

(ft^). FIGURE 4-12.—Airblast fan-intake control.

58
Feet

per minute

Seed cotton 4,000-5,000

Seed cotton in tower drier 1,500-2,000

Dried seed cotton (from machine to

machine) 4,000-5,000

Seed 5,000-5,500

Hulls and trash 4,000-5,000

Lint cotton 1,500-2,000

Keep in mind that the flow of air in a pipe

is similar to the flow of water in a pipe, although flow rate is measured in cubic feet per

minute instead of gallons per minute. Pressures

within the air pipes are expressed in inches of

water (in H,0) measured on a U-tube gage or

manometer, rather than in pounds per square

inch. Most cotton-gin centrifugal fans operate

against static pressures or resistance below 1

pound per square inch (27.8 inches of water).

The number, size, and operating rate of gin

stands will determine the required rate of flow

of seed cotton to the gin (usually from 8 to 30

bales per hour). This flow rate and the layout

of the gin floor should determine the dimensions and arrangement of the piping (table 4-

4). The air pressures needed to overcome the

resistance of equipment and pipes and the quantity of cotton needed to supply the gins will

determine what fan capacity is required.

AIR MEASUREMENTS

Even when fan speeds, wheel diameter, and

other factors are known, it is difficult to predict fan performance accurately. The only reliable way to determine how a fan is performing

and to determine a system's characteristics is

by making air readings. Pneumatic systems in

gins vary greatly, and no two installations are

identical. However, the necessary determinations can be made with a relatively simple kit of

tools and instruments containing the following

items:

TABLE 4-4.—Suggested seed-cotton pipe sizes

for various ginning capacities

Ginning capacity Seed-cotton pipe diameters (inches)

(bales/hour) Unloading^ Drying systems

6-10 13 14

11-15 14 16 or two 12

16-20 16 18 or two 13

21-25 18 20 or two 14

26-30 20 24 or two 17

Conveyor pipes from the telescope to the separator.

1. A 3%-inch-diameter standard or a Vs-închdiameter pocket-size pitot tube. The i/ß-inchdiameter pitot tube is accurate enough for all

practical purposes in round pipes up to 24

inches in diameter. It requires a hole in the

pipe only 9/64 inch in diameter, which is not

large enough to require patching.

2. A manometer or U-tube to measure velocity pressure (P^) and static pressure (P^). A

24-inch manometer should be sufficient to check

fan-system characteristics, with the exception

of static pressure in a series fan unloading

system.

3. Two 5-foot lengths of rubber or plastic

hose to connect the pitot tube to the manometer.

4. Speed indicator for measuring fan

speeds.

5. A measuring tape for determining pipe

diameters.

6. Tables of airflow for various pipe

diameters and velocity pressures.

To find the volume of air, velocity, pressures,

and horsepower in a piping system, readings

must be taken at the fan inlet and discharge.

Since a fan may be used either for suction or

for blowing through pipes, the static readings

are taken at both the fan inlet and the fan

outlet to find the overall static pressure. An

outlet reading is all that is necessary on a fan

used only for blowing. Readings may also be

taken wherever information is needed, such as

at troublesome points in suction, drying, and

airblast piping systems; and at separator inlets

and outlets to determine leakage. Test holes

should be located approximately 8^4 pipe diameters downstream and II/2 pipe diameters

upstream from elbows and valves when possible. Gin fans usually operate at static

pressures ranging from 5 to 26 inches of water.

The following are directions for using the

test kit:

1. Fill the manometer half full of the liquid

(water or oil) recommended by the manufacturer. An oil manometer is preferable to

prevent damage from freezing in cold weather

operations.

2. Connect the manometer to the pitot tube

with the two lengths of flexible hose.

3. Insert the pitot tube into the test hole,

until the end reaches the center of the pipe.

The stem of the pitot tube should be kept at a

right angle to the pipe, while the nose of the

tube points upstream into the air current.

59
g^

Ci.

"S.

i

>

ce

CO

HO

Ci

o

•g

?S5

rO

^

<

«oeoeONOi ooo»flt»t- tHi^ooO"^ eo»-ioot-oo '<i»iONt-os oo«-t»Heo «Oi-ioot-o» IO-^îDCO'* Oioseceot- t-eO'>*»H

«crH»HcoiO t-oiOiOitH osNCio-^ íCíoeocfteo «ot-t-uaw OI-^OOIHCO "tr la -^ CO 1-t oioc^ooeo t-»HU500O ca-^ioto

OOOOCOiD OOOiOOSOi t-iP^NO ÍOCOOÍOCO 0>»Äi-tt-CO 00'<*a5lO© U50U3010 OS'^OSeOOO Nt-rHlO©'^00C<I<O

kûOOOirHN C0'^«OiDt> (X?OSOi-HrH oieO'^TflO lOíOt-'t-^OO OOoToîOiH i-ícÍcíeOCO eO-^fTÎliSàO íOíOt-t-00 OOOOOiOi

^,_l rHrHrHiHrH i--lrHC<IC^C^ COC]C^C<]C^ OlC^C^dCa NCiC^COCC COCOCCCCC«? CCOOCOCOCO COCOCOeCCO COCOCCCQ

«ßOOirHiO OQOOt-OO Oil>U5t-U5 MOO-^C^l CXJOOOiOO t-«Ot»OieC OOCOOSOi CONIßCClß OOOlOOiOS lOiOlOO»

COOO-^t-eC 05àO«000 «OOSOSiOr-t n<U5n<i-lt- tHUSt-t-t- «O-^rnt-CC OOC^kOt-OS ï-lNCvINr-t 000«OeOO t-COOS""*

050i»0000 000>00<0 COOt-Tfr-t t-CC0iU5O «Dr-ttOrHiO rHiCrHiOO 'ffOSÇCt-rH '*®'^00NtOOi^eOt^rH^00rHlO

^^oooTtH ci eô eô -^ lo çot^tr^oooT oToorHci Necco""*.^ ißioictot^ t^t-^oooooT OSOOO»H r-tr-tc<ic»ieo eoeo-^rj«

^ rHiHr-l»HT-l tHrHrHrHi-H »HCINCICO NNNNN NNNNN OÎC<lC<IC<IC<l CJCOCOCOCO eOeOCOCOCO COCÇCOCO

íOOOr-tiHíD -^Oit-t-OO •^C^'^COM OOt-lOON NTHOîOOOO OCOOSt-Oi Iß-'l't-IOt- <*íO-«il't>-U5 OOíOOiOO COIOTTO

lOrHt-THtH C>1IJOCO«OíO tH-xfríteqQO OJ'^àOUSCC OíOO^ft- 0»HrHtHO Oit— -^»Ht- COOOOOt-tH lOOOON"^ íOt-OOOS CJOeClOiO •^oaOt-T»« rnt-eOOS-* OIAOUSO IOO-^OON t-rHIôOiCO «OO-^OOTH »ÛQONIOOJ^ C^l^lÖOi^C^lO '^'^"^'^

"^iOt>»odos OiHOÍcíeO rf "^ là lâ <¿ t-'t-'oOOOoT OiOiOOr^ iHcÍNC^eo CO -^ "^ '•t to lOlO«C<OíD t-t-t-OOQO OOOiOiOi

^^rHfHtH ^rHr-lrHr-l ^iHi-HrHrH rHt-l(N<NCg (NNWNN <NMN(N(N CvJ<MNN(N NNNMC^ (NNMN

OOOrHClOO C<I'^«O00t- íOrH^OO"* ^tH'^íOt- t-OOO^rH ONOOt-iH OSíMf-t-^N t-t-eOU5^ OiOOCOlO ^OiCOCO

C^ldOOlOO 00OS»Ot-íO NïOC-iO"^ OlOOOOrH rHOOtOCO OS-^OOWÍO OOtHCO-^tó IßlOkO'^eO rHOt-iOM OiUSWOO

íCrHC^C<lr-( OOlOCaoO'* OlOOlOO líSOSCOOOCJ íDOCOt-rH -^OOr-l»«« rHlOOOrH'^^^ t^OCCíOOS^ OJIOt>OeC líS^ 00 rH CO

eCWíDt^od OOOÍOOr-T oícícoeo*"^" -xf-^lOtóS«© «Dt>t>l>00 OOOOoToToi OOOIHTH r-IC^]OÍC^]C^ eCeOCO-^"^ Tfi^ilfSIO

" """'^;:í^ ^;H,HiHrH rHrHrlr-lrH rHrHr-lrHr-1 rH,-trH.HrH C<I<N<N(N(N <NC*lNCqCvl (NNíNNCO Cg<NN(N

t-Oit--«*« MfHOiiHlO «DlOíOfHíH OOeOt-1-ttC eOrHCOt-lO «ONC^OOOS af5íDeOt-íO N-^eOQOíH Ot-OrHO laOlOOi

•^Ot-OiTH tO«OiH'*cO OIOOOOO QOCONOOCa «OOíTHMCO CCeONOOO «OCOOíON 0OeOCX3C<lt- TH-<*O0i-HTf «COOIHOJ

OeONOOO -^©«OrH«) THIOOS'«1«00 »HàOOiCg«£> OSCgïCOOl líSOOrH-^^^íC Oi^MkOt>0 (NlOt^OC^ »ßt^OON-^ «CQOíHCO

05'^U3<0«0 t>000do>O5 C>00»-r»H NOÍNCOCO eO"<f'<*'^U5 kOlOíOtDíO ^Ût-t^t-^OO OOOOOOOiOS OSOiOiOO OOi-liH

tr-tfHrHr-(»H >-(»Hi-HrHrH r-(THrHrH»H »H»HrHr-4iH »H»HiHrH»H rHrHi—l?HrH iHiH»-(C*lC^ C<IC^CJN

íDíOOiCOOO OlONOiCft C»t-O00N lf5t-OS»HíC MN-^iHi-t íDíOiHiH«© OOkOOOOOiO OOb-'^OOOS t:-C<IU5íO-«t OieO"«!«"^

t-c^Okoo o-^àôcjc- oiHrHooko o-^t-Or-t ojNr-tooo ißc^osioo loo-^fooN kÄooiHcciß t-osOi-toi c^wooec

t- Oi QO lO C^ OOCCOOCOt- NOOeOt- tH-^t-rHTf t-OC0«>C» rH-^íDOiC^ "^t-^OlrH-^^ tCOOrHCOlO '^^^"^^^ °S.®*Í>"^.

CsíeC-^USíO íOt-t-^OOOO oTosOOO rHi-Tr-ÎNC^Î cícOCOeoeO <t'<t"-^-^"u5 la la là iß iO íO«©t-^t-t> t-t-OOOOOO OOOIOíOí

OOIHNíOTH OONOJ-^CO dcoosweo eoec'^«OiH o»Ht-«5i^ OWIäIHN OIûîOCCOO Oit-eo«o«o •<<j<oieoeoca «-^íottHíOíDeCeO «0«0NU5«0 »OC^l>C<IàO t-000Ot-«O •^»Ht-COOi "«fOOCgtOOi C^l-^íOOOOS Or-tdNN Nr-lrHOOS t-tO-^N

aíSifSWOíO rHíOíHiOO C0t-0-«*t- OCOíOOiM lOOOOCCkO OOOCOißt- OCJ'^íOOO rHCOUSt^« »HeOlflt-^00 OC^J^'^^'J,

NeO-^*kOU5 OÇOt-^t^t^" OOOOoTcTor OOOOTH iHrHCÍoící cícOCCeOeO "^ ^ ^" ^ ^ lOíOaOIOlO íoccíotDíO t-t-t-tiHrHr-liHr-l iHíHrHiHr-l rHiHr-lrHf-l rHrHrHrHiH rHíHT-tiHrH iHiHiHrHrH rHf-(iH»H

M-^toiac^i t-eooooJt- b-co-^eoc^ ooc<i«oco "^oos-^eo OOOíOOOOO eo«oi«c<i»o «o-^oseoco c^ co eo la la -^©»ooo

t-iHCO-^OO íOtHNrHOO COt-OiOO OSt-'xtOíC iHt005C0«O OOONCO'«*« lftl«U5lOTÍ< WNOOit- lONOt--^ »H00"^O

C^ Oi Oi lO <Z> lO o Tf 00 rH lO 00 rH tó OO © CO^ ÍC (Ä rH -^^ «C 00^ rH CO IÖ 00^ O N Tf tO 00 O^ CJ -^^ íO 00^ O^ »H CO W l> Oi^ O OÍ -^f^ aí5 t-^ Oi

NCOCOTjTkO lOíOíOí¿"t> t>t>O0O0OD OraTosor© ©©©rHr-T rHiHoTcÍN C^NCOCOCO COCO'^'-^-'t Tf-xir-^lOlLO U5IOIOIO

©lOeOOSíH íOt-OiOi© »««0'«1<N© 05©'^rHC<l

^CX)COt-íD OSCft«OiHlí5 <£>«OU3CO© àOrHlOOSOJ

©00ài5©kO OSCOt-rH-^ t-©C0í005 THT1»«CO0IM

t- t- N N 00

Tj< «o 00 os os eO U5 t- os r-l

osco-^N t-oot-eot~

OSOSOOt- kOCOrHOSíC

»ßt>OSt-l COlOC-00©

00 t- -^ 00 ©

CO © t— CO ©

M -^ lO t- os

© os »ß © CO

ÍO r-l t- CO 00

© ea CO lo <o

IßlOCO«! <Ot-l>t-t> 0000000005 OSOSOSOS© ©©©©r-t r-(»-l»-trHC^ NNC^1C>1C<I COCOCOCOCO COCO'

OSCOr-IOSOO «©-«itiOOOeO '^C<l©t-íO t-»HOS©«D

iHt-»OCOO UíiH'^faOUÍ CO©«)©-^ t-©THCOCO

O0U5r-l<O© -^OOiHitt- ©COIOOO© NàOt-^OSiH

rHoieoco"^ ^ ^»OiOàis «s©coíOt^ t^t^t^t^oo

t-Ti<ißeot:- t-'^t-ooio

COOONiHOS t-lßC^lOSiC

CO lo i> OS © <N '* <*, •>. os^

ooooooooos osoTososos

iNiHoseo iOt-»ßc<it-

»0SlßO«0 r-(«0»-l«0©

i^N-^^íDt> os_©cacoio

"©"©©© ©r-TrHiHrH

©rH©O0U5 oseowíO

U5©COíO© O0t-©CO

íCt>OS©N W"^_^«>t>

NÄiHCO-"* 00Tí<MIA«I

iHt-oscí© Tjtçouscoos

(0(Mt:-*c^i© osdiooo©

la eo rH © M

«}< 00 r-i eo -«j»

00 lO 00 © N

rHNc<ieoco co-^-^-^iß loioiatoío

»lOt-lOt- ißOSOSiOOO OO-'tOOOSt- COt-OOt--^ ©OOlßißCO

««• ^eoN© CO lo e<i ai la r-it-c<it-M t-i-Hooseo t-©coíOOs

'*»00©C>J COIOC-OO© NCOlOíCOO OSrHMCOl« «©ooos©»-^

íOíD«ít-"t-^ t-^t-^t-t^oo ooodoooooo ooososoTos ososos©©

os -fíl 00 © rH

rH -^ «o os rH

CO Tf lo «» 00

© os ÍO *H

CO "«I« «o 00

os © í-H CVI

©©©©© ©rHi-Hi-l

«DCOCOCOt- ©OOÍOOS

rH©IOCOíO t-Tl«©-<!ji

Tf © '«f 00^ 1-K -^^ «> O. N

i-í C^í oí CÍ CO CO CO* V -«f

ooi>t>©ío too©

OS©©©00 tO'sfrH

»OSrHCOrf ÍDOO©

•^ -<t là là \à là ïà tjí

c<j-^eoosoi co©ií5oooo «oeot-©© ©^N«OOO ©©OO os-ít^cooo c<i io o e^ la OOI-HCOUîOO a T-* CO -^ lO t-oooo ^iot-©© Nco-^iot- oo©iHOJeo Tf«>^t^ooos^ ©»HCJ

©iOifiTçot-' t^t>t-^t^t^ t^ododooocT odododoood ©osos

© © 00 íO N

- — " os ©

CO la

f- »H CO to

o iH r-t .H

ÎO t- 00 ©

©©©© ©©©©

•"^kOC-00© N»0©NN N-^f^t-© <Ot-U50000

co-^coiOiO N»©©© ©t-->«i<»-tt- cooocot>»-t

cat-TH-^t- ©N"^t-© ©oiTfot^ ©©eacoio

1-7 iH (N ci oî CO CO cd cd CO* Tí«* ^ -»t -Tir rf* 'rf \â là \à iâ

'^ t- oc ïO

iO 00 ïH -^ ÎO t^ ©^ ©_^

t£5 IÍ5 IÖ çd

rs© c^iH©kO00 ©©ooio© coiftcocc-^ »-tt-THwt- ©©©

tt© ©»HN'«1'»0 t-oooo©© ©©©©© ©©©OOt- íOíA-^í«

?rH C<I-»t»0«Dt- 00©©rHÇO -^lOtOt-OO ©©©rHOl^CO-^kO

dio tded'id©© «Tid't-'t-t-^ t^t-^t^t-^t- t^t-'ododod odoooo

Iß ©^

00 00 00

<*IOCOOO© ©USWM-^

©©•^Nt- ©rH©©©

©lO00rHeO©00©rHÇO

i-T rH FM cî c<r ci ci ed ed CO* co co^ co co

Ci ^ fO 1-* y^ ©t-'^t-OO lO©CJCJI© »000©©tCJO0COO0C>J laOOfHCOàft t-©©r-tC<l cic<icooic^i

li5©O0©T-4 C»lCOIA©t- O0©i-IC<ICO -«JikO^t-OO

^ 00 Ol -«t «i<

ej 1-t TH © ©

© © TH C<l Ol

co OJ 00 -^

00 t- ài5 -^ ^

co -^ lO © 1 ^ ^ xf'«*'«* '^ 'Tt la la la ïO ta lo ta lo lo©©©© (©to©©©

C<l»flt-t-t>- ©"»1«»Ht- i-l©t-IÄCO i-l©t--^ 00^ 00 os © rH C^ Ol^ co "^^

*©©t^t-^ t-^t^t^t^

t-C^OCOt- rHO0TÎ<©t-

©OOt-tHM OÎ©©C<l©

©ojiooo^© OJeokßt-^oo^

t-î i-T TH ci ci ci ci ci ci

t-©©oaiH ©oo©©ri« -^c^ioo

© ^©©r-l C^ieO-^lO»« kOlOTt

©r-<C<ie01ß ©t-OO©© rHCsICO

00* co* co' eo* co* co* cd cd eo* '^" -«t* V -rf

C^©t-C<IlO t-0000©CO

oirH©oo© «i<eq©oo©

©t-t-00© ©i-iCJNCO

© »toot-4co lOioioeoiH oo©iH©

COfH00©C0 ©t-'«l»rHO0 -^»HOO-^

TfàOlOiOt- 0000©©© rHOIC<ICO

c<i©©coeo ©u3-^io© ©©©©©

<0 © 1-^ d © © ^^ tß 00 © C^ 00 ^ tñ Lß '^r ^^7^ vj w^ ««»' w« L^ uw w*ai ^<^ <^j uw v«;

t-©CO»Ot- 00©rHC^-«il' VO©t-00OS ©rHCJCOTf "«tàO©t-^00 OOOS©

^^^ri r-Tcicicici cicicicici cocdcdcdcd ododedcdcd edcd"^"

i^«.^ lOlOlOlOlö ißlfJlOiOlO àOlOlO©© ©©©©

cococMos Tnooi-teqca iH©©c^t- ©eo©t-oo oot-»öeo© ©c^t-M t-àoeo© ooiooo©t- -^©t--^© t-co©iOrH c-co©»o»H ©oit-eo

.«,rt»^o<^ nn,-»s,-s_i_< CsJCOeO'^lO lO©©t-00 00©©©rH »-10^0100

^'"^ ^V'^ -«jr^^iKjr.^" V'«i<''^udw 1010U510

•»HC^©t- T-tCOCOOl© TjtOO i^TífeoíMCí» í3il>-»fteoO COI«

© © © © 00 Ol © ^ © TH 00 r-i © © 00

CO © © kO © ^ © 00 00 © 00 00 t- \a CO

© 00 o OJ ^ to © r- 00 © © CM CO ^

1-t r-l r-l rH lH r-t TH fH OJ ej eg CJ Cv]

oo©THTriö ài5co©-^oo

iH©t--«l<iH OOUSi-tOO-Tjt

àOàO©t-00 00©©©i-H

cicicicici cicicdcdcd cdodco~cdeo

© r-i r-t © 00

TH t- CO © -^ _ _

CM c<i CO CO -^ \o la

II

-2 i W

©r-ICO©© ©©CM©CO

r-tCMOOCM-^ "^"^-^COiH

lOt-00©rH CMCO""*»«©

©©00U5 ©C<1COOO© t-C<l©00©

©00©t- •^©©CMOO C0©-^©»0

t>^ 00 OS^ OS O iH r-J^ CM CM CO 00^ Tl<^ -^^ iO

' rH rH «-T r-T ci ci ci ci ci CM* CM* ci ci ci ci ci ci CM" CM"

© © 00 © CO

© lO © -^ ©

© © © t- t00©00©»H t-©©©Tfi ÇO©COOO© CMTH©COCM ©©CM-xfia

©t-©©© 00©'ç|<©t- C0©»0©© r-t©©U5© •<t©eOt-rH

Tfioiooo© ©©THCMCM coeo-^àoio ©©t-t-oo oooo©©©

^ Ti< CM © tlO © CO t- ©

© © r-l rH CM

CM CM CM CM CM CM

O © ,^ t>- CM t- CM 00 CO 00 \a \a © © t- t- 00 00 © ©

CO CO CO CO CO co 00 CO 00 00

© \a © CO r- © CM CO "Tf tß

00 00 CM r- © © Tf 00 CM

00 00 © © © © r-l CM

CM CM CM CM 00 CO CO CO CO 00

00 © Iß © •<*< t- 1H -íí« © 00

xf t- rf 00 kß OÜ •^ CM CM CO 00 CO -^ •^ Iß iß

CM CM CM CM CM CM CM CM CM CM

rH©00©00 ©©CMt>-

eOOOCMt-Oa t-rH©©

© ©^ rH rH CM CM CO CO^ "«f

•^* ^* Tf* "xf* -^ Tf* -xt -xiT Tf

aßlß"«*CMrH 00©CO©

©© ^OOCM àO©C0©

CMCOCOCO'^ •^ ^Ißkß

COCOCOCOCO COCOCOCO

©rHCMOOCO COCMrH©

OOrHTjtt-© 0O©©CM

lß©©©t- t-t-t-00

ci CM* ci CM* CM* ci CM* CM CM*

©rHCM COCOCMrH© t-lßCM©aß rHißCM©»H lß©CO©© CM»ßt-©

^^^^ ^. .„^ ^ ^~ ..^t-iH-xl« t-©0O©© rH-^t-WCM lßt-©CMiß t-©CMTi<© ©rHCO»ß

^ O T-\ 1-* y-i CMCMCOCOeO -^"xt-xtlOtó Iß©©©© t-t^t-t-00 OOOOOSOSOS OS05^©0© ©rHrHrH

rHrH r-TrHrHrHrH rHT-TrHrHrH r-TrHrHrHrH rH»-rcÍCM*cÍ ci CM* CM* CM*

00©-^t-'©©©CMißkßOO©CMr|tkßrtiCM©kß©

©eOCOrH© IßrHt-CMt- CM©»HU5© COt-ö'^OO y-t

eo-^»ß©©t-oooo©~~~ ._.-, — — —^

t-rHCOCOt- lß©rH©t- CMlßt-0000 t-'*CMO0'^ ©COt-©00 ©00©©rH CMCMCMCMrH ©OSt-kßCO rHOS©CO© t-'x1<_ _

CMCM©tß© lß©'XltO0rH àO00»H"«l<t- ©CO©00rH CO©O0TH0O ißt-ÄCM-xf íCO0©rHTf ©t-©»-HeO iß©00©rH CO»ßt-0O

cMcoco"^»ß»ß©©©t-t-t'OOooooa'"~~'" ©© ©©©rHrH rHrHrHCMCM----- CMCMCOCOOO.-_COOOCO'^'* — .- -^ '^ '^f ÏG IG lßlß»ßiß

t-C0CO»ßCM ©©kOCMOO CMlßt-©© ©©00©'xl< »HOOlß

»ßCMt-rHlß OOrHTft-© CM-^tóOOrH eO'^©00© CMCO —

rHCMCMCOCO CO'«««"«*-^'^ Ißlßkßkß© ©©©©^ ^ "

CO 00 CO 00 CM

., -- _ - -. © rH CO Tf ©

t-t-t-t-t- 0000000000

©©TfOOrH Tft-©00»ß

t-©©»-ieo -xfißt-oo©

0000©©© ©©©©©

00 © CM -if ' © CM CO "^ 1 © © © © '

t- © © CM

xi<CM©00rH t--^kßeO©

lßCO©©00 CMaßCC>©kß

rH©OSCOlß 00©CM'xfiO

rH rH rH ci CM* CM* CO CO* od CO

00 00 CM © ©

C>î © © rH t00 © rH CO ^

• © t- rH CM

I kß © 00 ©

I t-^ 00 ©_^ rH

' -^ «* Iß kß

© "xC Iß Iß rH

00 rH CO kß tCM -t U5 © tllßO0O0©CM ©©rH©OS00©©rHCM CMCMCOCOCM

O0©rHCMCO ^lß©t-00

Ißißkßlßkß kßtß©©© O©©©©

kß»H»ßoo© rH©©«jco ooeot-©

CMCMrHO© OS00©»ß-^ CMrH©00

OS^©rHCMcO CO'^»ß©t- 00©©©

©t-^t^t^t- t-^t-^t^-^t-^ t-^t-^t>^od

rHCMCO-^lß ©t-OO©© fHCMOO-xJJIß ©t-^ 00©© rHCMCOtl<U5

rH rH CM CM CM CM

^ \a ©t-OO©© rHCMCO-xflß ©t-OO©© rHCMCO-xJIkß ©t^ooos

CM' CM CM CM CM* CM cd CO CO CO CO cd cd cd cd 00 "«t «* -^ Tf «* -^ "<* Tj! ^" -»t

60
5 '* 00

00

<*

(N

Iß

CO

OSO

OS

OS

CO

o

lí5

o

(N 00

00

DOo

^*

(M CO CO CO

n (M

ai CO

os

os

(M

COO CO

OS

CO

CO

00

00

OS

CO

* U3 0 ce ce CO CO CO

to

CO CO

tico eo

00

CO

^J r-l

T> OS 5 CO

00

00 00

os

CO

to

CX)

o

oo

o 00

00

«o

to

OS 1 CO to 00 o

(N (N (NW (N

o

to

eg

OS

eg

oo

o

c:s

CO

tros

in

o

00

ino

eg

o

ego

to

(M (N eg

eg

eg

eg

eg

eg

eg

eg

eg

CO

eg

CO

eg

CO

eg

CO

eg

CO

to

to

(N

00

oo eg

o

OS

00m

to

to

CO

OS

CO in

eg

CO

mo

in

OS OS

o

eg

o

eg

o

eg

o

eg

o

eg

o

eg eg eg eg

00

CO

00

OS

OS

in

eg

COom

in

cto 00

egO

00 eg

CO

ino

in

rH

t- 00 00 00 00 00 OS OS OS OS

Oo

o

CO

eg

00

00

CO

inm

oo in

00

oo

00

in

00o

CO

to

in

>4< o

to

CO to

r-l

to CO co to tr- tr- t-

^

^

CO

CO

to

CO

00o

OS

00

os

00

os

t>

eg to

eg

os

OS

CO

co

in

tto

CO

OS

OS

'^

^ "^ Ti< ¡^ in

mm in in in

to

00

CO

OS

OS

o

eg

in

eg CO

CO

OS

in

to

to

CO

to

in

00

in

tros

CO

OSo

(N (N CO CO CO CO CO CO CO CO

^

to

OS

00^

OSo

in

eg

to_^

CO

CO

tCO

00__

eg

in

os__

o

to

o_

eg*

tto

eg"

trcg^

eg"

OS

ireg"

CO

00

eg"

too

CO

e<i

eg

CO

OSo

ino

in

oo

to

OS

to

c00

co

00

00

eg

OS

oo

oo

o

o

oo

o

o

o

U5 eg CO

OS

00

CO

00

OS

tCOo

in CO

eg

to

CO

tros

CO

00

t00

in

in

00 00 00 00 OS OS OS OS OS OS OS

CO

Cvl

in

00

OS

in

eg

to

in 00

00

o

OS

00

eg

to

OS

eg

COo

COo

eg

c-

^N

t> t- t> t- t- t- t- 00 00 00 00 o

CO

in

oo

to

eg

CO

CO

CO

eg

tr00

t- 00

o

OS

CO

to

OS

eg

ego

to to to CO CO ee to to to to t^

to

00

o CO

OS

CO

in

00

OS

in

OS

to

oo in

o

00 00

oo

OS

lO in in

m in in in in in in in

->* lO

to

OS

o

in

CO

00

in

to

eg

CO

OS

CO

CO cCO

in

tOS

cto

CO

00

to

00

Tt TJ.

^ •^ -t "^ "«t -^ -^

^ Tt

too

to to co

eg

teg

00

tCO

00

o

in

00

CO

00

00

tros

o

in

OS

CO CO CO co co co CO CO CO CO CO

OS

00 00

ino

OS

CO

CO

OS

to

OS

00

00

OS

inOeg-^o00

too

in

OSo

eg

(N DJ eg eg eg eg CO CO CO CO CO

00

COo

eg

eg

eg

CO

eg

CO

eg

00

00

eg

00o

CO

OS

eg

CO

OS

CO

OS

CO

CO

OS

00

CO

OJ oa eg eg eg eg eg eg eg eg eg

COo

co__

00

to^

CO

co^

o

in

to

in

CO

to^

00

co^

to

OS

to

;:; to

eg

t>-_^ !>;

inm

CO

eg

in

CO

to

in

tco00 00

00

1-H

OS

OS

OSo

eg_^

OS

eq

to

CO CO

eg

CO

COo

eg

00

o tco

CO t>

CO

to

00 OS

ooooocoooc ooocoooooo

o T-icgco-^in toc-ocoso

in inmininin inm'ininto

^

<ÜoS

Measure the difference in liquid levels between

the two columns of the manometer. This reading is the velocity pressure (P^). The liquid

column levels usually fluctuate; therefore, read

the differences between the average high and

the average low.

4. Disconnect the impact pressure hose from

the pitot tube and leave the static pressure

outlet connected (the static pressure outlet on

the pitot tube is perpendicular to the stem).

Insert the pitot tube into the pipe in the same

manner as described in3 above, and measure

the difference in liquid levels. This reading is

the static pressure (P..) ; it may be checked by

withdrawing the pitot tube and holding the

end of the flexible hose over the test hole in

the pipe. The two static pressure readings

should be nearly the same.

5. Repeat procedure4 on the opposite side

of the fan and add the two static pressures

to obtain the overall static pressure.

After the Pr reading has been obtained, the

velocity of the air and the volume of air the

fan is delivering can be obtained from table

4-5. The left-hand column of this table gives

Pry and the second column gives the velocity

that corresponds to the Pr regardless of pipe

diameter. The body of the table gives the

volume for any given Pr reading for 0.1 to 6.0

inH.O and pipe sizes from5 to 30 inches in

diameter. The volume can be calculated for any

pipe size by the equation given in the notes to

table 4-5. The velocity for the velocity pressure (Pr) reading can be obtained from table

4-5 and the area of the pipe from table 4-6.

For example, assumea Pr reading of 1.6

inches of water ina 13-inch-diameter round

pipe; from table 4-5 we find that the velocity

is 4,617 feet per minute, and the air volume

is 4,256 cubic feet per minute. Since table 4-5

is based on standard air conditions,a density

correction factor must be considered if the fan

handles air at other than standard temperature

and altitude. Factors for correcting for

temperature and altitude are given in table 4-7.

EXAMPLE: If the fan in the above example is

handling air at 200°F and is located

at an altitude of 3,000 feet, the following

corrections should be made.

SOLUTION:

1. From table 4-7 we find that the correction factors

for temperature and altitude are 1.114 and 1.056,

respectively.

61
2. The composite correction factor = 1.114x1-056 =

1.176.

3. The corrected velocity =4,617x1.176 = 5,430 ft/

min.

4. The corrected volume =4,256x1.176 = 5,005 ftV

min.

CENTRIFUGAL FANS

Two types of fans are in common use in

gins, centrifugal and axial flow, but centrifugal

TABLE 4-6.—Area and circumference of round

pipe

Diameter

(inches)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

Area

Square

inches

Square

feet

0.79

3.10

7.07

12.57

19.60

28.27

38.48

50.27

63.60

78.50

95.00

113.10

132.70

153.90

176.70

201.00

226.90

254.40

283.50

314.10

346.30

380.10

415.40

452.30

490.80

530.90

572.50

615.70

660.50

706.80

754.70

804.20

855.30

907.90

962.10

1017.80

1075.20

1134.10

1194.50

1256.60

0.005

.022

.049

.087

.136

.196

.267

.349

.442

.545

.660

.785

.922

1.069

1.227

1.396

1.576

1.767

1.969

2.182

2.405

2.640

2.885

3.142

3.409

3.687

3.967

4.276

4.587

4.909

5.241

5.585

5.940

6.305

6.681

7.069

7.467

7.876

8.296

8.727

Circumference

(inches)

3.14

6.28

9.42

12.57

15.71

18.85

21.99

25.13

28.27

31.42

34.56

37.70

40.84

43.98

47.12

50.26

53.41

56.55

59.69

62.83

65.97

69.11

72.26

75.40

78.54

81.68

84.82

87.96

91.11

94.25

97.39

100.53

103.67

106.81

109.96

113.10

116.24

119.38

122.52

125.66

fans are in the majority. The centrifugal fan

has a single inlet and is fully enclosed in a

cast-iron or sheet-metal housing in which

bladed wheels revolve (fig. 4-13). Size designations are confusing because each manufacturer

uses his own descriptive terms. Many fans,

however, are designated simply by size from

No. 20 to No. 70 or F-76 to F-238.

Rembert fans (fig. 4-13, C and D) with

perforated flat disks or cones permit the material to pass through the fan housing without

damage from the wheel. These fans are generally used for transferring seed cotton from

one location to another (such as from trailer

to storage place) without use of a separator.

Fans should not be operated at speeds higher

than necessary, and wheel-tip speed should

never exceed 18,000 feet per minute. If it becomes necessary to speed up fans, resulting

changes in performance may be calculated from

the following basic laws:

1. Capacity (cubic feet per minute) varies

directly with the speed (revolutions per

minute).

2. Pressure (inches of water) varies as the

square of the speed (revolutions per minute).

TABLE 4-7.—Air velocity corrections for temperature and altitude^

Temperature Correction Altitude Correction

CF) factor (feet m.s.l.) factor

0 0.932 20 1.000

20 .952 500 1.009

40 .971 1,000 1.018

60 .990 1,500 1.028

370 1.000 2,000 1.037

80 1.009 2,500 1.046

100 1.028 3,000 1.056

120 1.046 3,500 1.066

140 1.064 4,000 1.075

160 1.082 4,500 1.086

180 1.098 5,000 1.095

200 1.114 5,500 1.106

225 1.137

250 1.157

275 1.177

300 1.197

350 1.236

400 1.273

450 1.310

500 1.345

Area=3.14 X ^^^"^eter^ _ ^^^g^^ ^ diameter^.

Circumference = 3.14 X diameter.

1 For correcting table 4-5 for other than standard

conditions.

2 Sea level. Standard condition.

^ Standard condition.

62
3. Power (horsepower) varies as the cube

of the speed (revolutions per minute).

These laws are expressed in formulas as

follows:

Original capacity

Final capacity

original speed

final speed

Original pressure original speed squared

Final pressure ~ final speed squared

(1)

(2)

maining the same, the speed is doubled to 2,200

revolutions per minute. The volume of airflow

will be doubled, to 5,000 cubic feet per minute;

the static pressure will be increased to 24 inches

of water resistance; and the power consumed

will increase from the initial 5 to 40

horsepower.

(3) Original horsepower _ original speed cubed

Final horsepower final speed cubed

Motor current can be substituted for horsepower in equation 3, with only a slight error,

so long as the voltage and frequency remain

the same. This will be more convenient for

ginners since motor current is easier to

measure than actual horsepower. The results

will be accurate enough for field calculations.

Original motor current.

Final motor current (4) original speed cubed

final speed cubed

Many ginners do not realize what equation 4

means to them in power consumption. If the

speed of a fan is doubled, the capacity is also

doubled; but the resistance pressure is four

times as great and the horsepower consumed is

eight times as great.

Assume, for example, that a fan operating

at 1,100 revolutions per minute and delivering

2,500 cubic feet per minute of air against a

static pressure of 6 inches of water is using

5 horsepower. With all other conditions reFiGURE 4-13.—Representative types of cotton-gin fan

wheels. A, Plain eight-bale wheel. B, STirouded

multiblade wheel. C, Rembert-type wheel in casing.

D, Rembert-type cone developed by the USDA

cotton ginning laboratories (public patent).

TABLE 4-8.—Selection of fans for most efficient operation

r^ . Most efficient Static pressure2 Fan size or —

equivalent Capacity range Speed ranged Straight-blade Multiblade

(ftVmin) (r/min) (inH^O) (inH 0)

—1^ _____ _—_—

Single 20 1,250 to 1,750 2,200 to 3,000 Up to 14 Up to 17

Single 25 1,500 to 2,000 1,800 to 2,800 Up to 16 Up to 19

Single 30 2,000 to 3,000 2,000 to 3,000 Up to 18 Up to 21

Single 35 3,000 to 4,000 2,000 to 2,600 Up to 18 Up to 21

Single 40 4,000 to 5,000 1,800 to 2,400 Up to 22 Up to 24

Single 45 5,000 to 6,000 1,600 to 2,200 Up to 23 Up to 25

Single 50 6,000 to 8,000 1,400 to 2,000 Up to 22 Up to 25

Parallel 40 8,000 to 10,000 1,800 to 2,400 Up to 22 Up to 24

Parallel 45 10,000 to 12,000 1,600 to 2,200 Up to 23 Up to 25

Parallel 50 12,000 to 16,000 1,400 to 2,000 Up to 22 Up to 25

Series 40 4,000 to 5,000 1,800 to 2,400 Up to 44 Up to 48

Series 45 5,000 to 7,000 1,600 to 2,200 Up to 46 Up to 50

Series 50 6,000 to 8,000 1,400 to 2,000 Up to 44 Up to 50

1 Fan wheel tip velocity should not exceed 18,000 ft/min.

- Fan intake plus discharge static pressure. These values will vary slightly with

manufacturer and number of blades on wheel.

63
Care should be taken to choose a fan that

will be operating within the most efficient

capacity range and within the speed range

recommended by the manufacturer. Table 4-8

can be used as a guide for selecting fans for

their most efficient operation.

Most manufacturers base fan performance

ratings on handling standard air at 70° F and

29.92 inches of mercury barometric pressure,

and weighing 0.075 pound per cubic foot. Corrections to pressure and horsepower for variations in temperature and altitude are given in

table 4-9.

EXAMPLE: Select a fan with a capacity of 5,000

cubic feet per minute at 140° F with

a system static pressure of 12 inches

of water to be operated 2,500 feet above

sea level.

SOLUTION:

1. From table 4-9 we find that the correction factors for temperature and altitude are 1.13 and

1.10, respectively.

2. Composite correction factor = 1.13x1.10 = 1.24.

3. 12 inH20 X 1.24 = 14.9 inH.,0 static pressure at

70° F and sea level.

4. Fan performance tables of one manufacturer

show a size 40 gin fan has a capacity of 5,000

ft^/min against a static pressure of 15 inH^O at a

speed of 1,800 r/min and will require 18.7 hp.

5. Correct the horsepower and pressure to operating

conditions of 140° F and 2,500 ft altitude:

18.7 hp -^ 1.24 = 15 hp.

14.9 inH.O -^ 1.24 = 12 inH.O F,.

6. Final performance at altitude and temperature:

5,000 ftVmin, 12 inH.O P„ 1,800 r/min, and 15 hp.

The performance characteristics curves of a

fan provide a good means of determining its

capabilities; the performance of fans of the

same size designation will be slightly different

for each manufacturer. Use the correct curves

for manufacturer and fan size when checking

fan performance. Figure 4-4 shows the performance characteristics curves for a size 40

straight-blade fan. If the fan capacity and

speed are known, the static pressure (P,) and

horsepower (hp) can be determined from the

fan curve as follows: Go to 4,500 ftVniin on

the X-axis and move vertically until you intersect the 1,800-r/min curve for horsepower

(hp). Now, move horizontally to the right and

read 18 hp on the Y-axis. Return to 4,500 ftV

min on the X-axis and move vertically again

until you intersect the 1,800-r/min curve for

TABLE 4-9.—Fan performance corrections for

temperature and altitude

Temperature Altitude

CF) Factor (feetm.s.l.) Factor

0 0.87 10 1.00

20 .91 500 1.02

40 .94 1,000 1.04

60 .98 1,500 1.06

270 1.00 2,000 1.08

80 1.02 2,500 1.10

100 1.06 3,000 1.12

120 1.09 3,500 1.14

140 1.13 4,000 1.16

160 1.17 4,500 1.18

180 1.21 5,000 1.20

200 1.25 5,500 1.22

225 1.29

250 1.34

275 1.39

300 1.43

350 1.53

400 1.62

450 1.72

500 1.81

1 Sea level. Standard condition.

~ Standard condition.

0 2,000 4,000 6,000 8,000 lOjOOO

CAPACITY, CUBIC FEET PER MINUTE

FIGURE 4-14.—Typical performance characteristic

curves for a No. 40 straight-blade fan.

64
TABLE 4-10.—Ampere ratings of three-phase,

60'Cycle ax. induction motors^

TABLE 4-10.—Ampere ratings of three-phase,

60-cycle ax. induction motors'^—Continued

Hp

Syn.

speed

(r/min)

Current in amperes

220

volts

440

volts

Hp

Syn.

speed

(r/min)

Current in amperes

220

volts

440

volts

1 3,600 2.9

1,800 3.2

1,200 3.7

900 4.1

iy2 3,600 4.3

1,800 4.6

1,200 5.2

900 5.8

2 3,600 5.6

1,800 6.0

1,200 6.5

900 7.3

3 3,600 8.2

1,800 8.7

1,200 9.2

900 10.3

5 3,600 13.3

1,800 14.0

1,200 14.6

900 16.2

71/^ 3,600 19.4

1,800 20.3

1,200 20.9

900 23.0

10 3,600 25.5

1,800 26.6

1,200 27.1

900 29.8

600 34.0

15 3,600 37.7

1,800 39.0

1,200 39.3

900 43.1

600 49.1

20 3,600 49.6

1,800 51.0

1,200 51.4

900 55.8

600 63.6

25 3,600 61.5

1,800 62.8

1,200 63.3

900 68.5

600 77.8

30 1,800 74.7

1,200 75.0

900 80.7

600 91.8

See footnote at end of table.

1.5

1.6

1.9

2.1

2.1

2.3

2.6

2.9

2.8

3.0

3.3

3.6

4.1

4.4

4.6

5.2

6.7

7.0

7.3

8.1

9.7

10.2

10.5

11.5

12.8

13.3

13.6

14.9

17.0

18.9

19.5

19.7

21.6

24.6

24.8

25.5

25.7

27.9

31.8

30.8

31.4

31.7

34.3

38.9

37.4

37.5

40.4

45.9

40

50

60

75

100

1,800

1,200

900

600

1,800

1,200

900

600

1,800

1,200

900

600

1,800

1,200

900

600

1,800

1,200

900

600

98.0

98.4

105.0

119.0

122.0

123.0

130.0

146.0

145.0

146.0

153.0

172.0

179.0

180.0

188.0

210.0

235.0

236.0

247.0

273.0

49.0

49.2

52.5

59.5

61.0

61.5

65.0

73.0

72.5

73.0

76.5

86.0

89.5

90.0

94.0

105.0

118.0

119.0

124.0

137.0

1 The ampere ratings of motors vary somewhat, depending upon the type of motor, but the values given

here can be considered average for the various types.

In the case of high-torque squirrel cage motors, the

ampere ratings will be at least 10 percent greater than

the values given.

static pressure (P^). Now move horizontally to

the left and read 11.5 inH.O on the Y-axis.

If you wish to increase the volume of air to

5,000 cubic feet per minute, the necessary speed

of the fan can be calculated with equation 1:

Original capacity _ original speed

Final capacity final speed

4,500 _ 1,800

5,000 final speed

Final speed = 2,000 r/min.

The new horsepower and static pressure can

now be determined from the performance

curves in figure 4-14, and as previously

discussed.

If fan performance curves are not available,

the new conditions can be calculated if the

original speed, static pressure, volume of air

flow and motor current are known. This is done

by using the basic laws of fan performance.

65
A. TUBEAXIAL FAN

A tufcwâxtal fsn ooDsiiU of ta uUl flow

whMl within t ejr""«!«'' '' ^ <l««llM<l ««

mov« air through > wid« ranf« oí volunw «t

low to médium ititlc pr«Muiw.

SUIOC VANE

«UIOC VANE

B. VANBAXIAL FAN

A vftoeaxlftl fan eonilat« of an axial flow

whe«l within a cylinder combinad with a act of

air guide vane«'located either before or after

the wheel. It la deelgned to move air over a

wide range of volume and preaaurea

C PROPELLER FAN

A propeller fan oonaiata of an axial flow fan

within a mounting ring or plate. It la designed to move air over a wide range of volume

at low static preaaurea.

FIGURE 4-15.—Three types of axial flow fans.

EXAMPLE:

Original conditions for a size No. 40 straight blade

fan:

Fan speed is 1,800 r/min measured with a tachometer.

Static pressure is 11.5 inH„0 measured with a pitot

tube and manometer.

Volume of airflow is 4,500 ft^/min measured with

a pitot tube and manometer.

Motor current is 23 A measured with a loop-around

ammeter.

SOLUTION: Volume of airflow desired is 5,000 ft'/

min.

Using equation 1 :

4,500 ftVmin 1,800 r/min

5,000 ftVmin ~ final speed

Final speed = 2,000 r/min.

Using equation 2 :

(1,800 r/min)-

(2,000 r/min)-

11.5 inH.,0

final pressure '

Final pressure = 14.2 inH^O.

Using equation S:

(1,800 r/min)

(2,000 r/min)

23 A

final motor current

Final motor current = 31.5 A.

Table 4-10 can be used to determine whether

the electric motor will be overloaded with this

increase in speed.

66
AXIAL FLOW FANS

Axial flow fans include those fans which

produce motion of the air by the thrust effect

of the inclined blades. The air enters axially

at the leading edge of the blade, and the flow

is essentially parallel to the impeller shaft. In

addition, the air is given a rotating motion

about the shaft axis as a center. Fans in this

category are usually classified into tubeaxial,

vaneaxial, and disk or propeller (fig. 4-15).

Propeller fans are rarely used in cotton gins.

A tubeaxial fan consists of a relatively large

hub with helical blades rotating within a cylinder, and will operate against resistance pressures of 2 or 3 inches of water. These are

sometimes referred to in the ginning industry

as clean-air or duct fans.

Vaneaxial fans consist of an axial flow impeller within a cylinder, combined with a set

of guide vanes located either before or after

the impeller. These guide vanes assist in recovering the energy imparted as tangential

Mechanical Conveyors

By D. M. ALBERSON

The mechanical conveyors used in cotton gins

fall into three main categories: (1) belt

conveyors, (2) screw conveyors, and (3) chain

conveyors.

Belt conveyors, although formerly used in

seed-cotton distributors, are now used primarily

for conveying cottonseed from under the gin

stands to a dropper discharging into a smallpipe pneumatic conveyor line. The principal

advantage of using the belt conveyor under

the gin stands is that it is self-cleaning. In

installations ginning cotton for planting seed,

use of the belt conveyor enables the ginner to

keep seed varieties separated with a minimum

of cleaning. The belt conveyor is efficient, requires relatively small horsepower, and has a

high carrying capacity. A properly designed

belt system has a long service life, and although

the initial cost is usually high, installation is

recommended where amortization of the initial

cost is assured through reduced cleaning costs

or for other reasons. Seed belt conveyor capacities are flexible because of the relatively

high belt speeds permissible. An 8-inch belt

running at a speed of 100 feet per minute in a

acceleration and, therefore, fans of this design

are capable of operating againststatic pressures

up to 6 or 7 inches of water.

Axial flow fans are sized by the diameter

of the cylinder housing. The basic fan laws,

which were discussed in connection with centrifugal fans, also apply to these fans. Performance curves can be used in the same

manner as for centrifugal fans.

One of the distinguishing characteristics of

axial flow fans is that they generally have a

drooping horsepower curve, with the horsepower being a maximum at no floiv. This is the

opposite of centrifugal fans, ivhich have

minimum horsepotver at no flow.

Unlike the centrifugal fan, axial flow fans

cannot handle material through the fan impeller. They are used in cotton gins primarily on

low-pressure systems such as lint-cleaner condensers and battery condensers. An access door

should be provided in the air duct on both sides

of the fan to facilitate inspection for lint fly

buildup, especially on the fixed vanes.

6-inch-deep trough will handle over 18 tons of

seed per hour at 75-percent capacity.

Screw conveyors and screw lifts are the most

common mechanical handling devices used in

cotton ginning, being used to convey cottonseed,

gin trash, and seed cotton. Screw conveyors are

simple and relatively inexpensive but require

more power than belt conveyors. The standard

pitch screw has a pitch approximately equal

to the diameter and is used on most horizontal

installations and on inclines up to 20°. Horizontal screw conveyors are usually operated in

a U-shaped trough with the screw supported at

various standard spacings. Screw elevators are

enclosed in cylindrical housings. The tube is

operated full with no brackets used between

ends. Screw elevators are normally used in the

gin only to convey cottonseed. Concise formulas

and data are not available for individual designs; however, the empirical equation given

below can be used.

Cubic feet per hour = 36.6

per minute,

XPXshaft revolutions

where Z)=screw diameter (inch),

d=shaft diameter (inch),

and P==screw pitch (inch) —normally equal

to D.

67
The actual capacity will be much less than

the theoretical because of screw-housing clearance, fluid characteristics of material, screw

length, material head, and lift. When specific

operating data are not available, an estimate

of 50 to 60 percent of the theoretical capacity

should be used.

In some areas of the Cotton Belt, chain or

scraper conveyors are used to elevate cottonseed from the seed pile into trucks for transfer

to the mill. These scraper conveyors are similar

to grain elevator conveyors; however, flights

are normally shallow and have widths ranging

from 12 to 18 inches. The capacity of such conveyors will depend on the incline needed. A

rule of thumb for chain belt capacity is: horizontal, 115 percent of conveyor flight volume;

20° incline, 77 percent of flight volume; 30°

incline, 55 percent of flight volume; and 40°

incline, 33 percent of flight volume.

Theoretical horsepower requirements

flight conveyors can be determined by

following equation:

for

the

Horsepower =

33,000

where 7;== speed of conveyor (feet per minute),

Lc=horizontal projected length of conveyor (feet),

Wc=weight of chain and flights (pounds

per foot),

Fr=coefficient of friction for chains

and flights,

Q=pounds of material to be handled

per minute,

L=horizontal projected length of loaded

conveyor (feet),

F^=coefficient of friction for material,

and ir=height of lift (feet).

The coefficients of friction range from approximately 0.25 for metal-to-metal contact to

0.50 for metal-to-wood contact. The materials

coefficient of friction for cottonseed to metal is

estimated to be approximately 0.80.

The power requirement of a screw conveyor

is a function of its length, elevation, type of

hangers, type of flights, internal resistance or

viscosity of the material, coefficient of friction

of the material on the flights and housing, and

weight of the material. Consideration should

also be given to the extra power required to

start a full screw and to free a jammed screw.

An approximation of the power required to

operate a normal horizontal screw can be

determined by the following equation.

Horsepower = CLT^F/33,000,

where C=conveyor capacity (cubic feet per

minute),

L=length of conveyor (feet),

"PF^^^bulk material weight (pounds per

cubic foot) (cottonseed=25-30

pounds per cubic foot, average

trash weight=10-12 pounds per

cubic foot, seed cotton=4-6 pounds

per cubic foot),

and F=material factor (cottonseed=0.9

and gin trash=0.9).

Screw conveyor size, capacity, and recomMAXIMUM RECOMMENDED SPEEDS

100 1,000

CAPACITY (cubic feet per hour)

FIGURE 4-16.—Capacity of screw conveyors.

68
mended speeds for normal gin operations are

given in figure 4-16.

Normally, a 16-inch, 5-horsepower unit is

capable of loading 30 to 40 tons of cottonseed

an hour into an average-height truck and

trailer. Some provision should be made for

raising and lowering the incline section to

adjust to the height of the sideboards.

Cottonseed Handling

By S. T. RAYBURN, JR., G. N. FRANKS, and C. S. SHAW

Seed at gins may be handled readily by

gravity, belts, screw conveyors, or pneumatic

piping. Belt and pneumatic conveying systems

are self-cleaning, but screw conveyors must be

hand-cleaned between the ginning of different

varieties if the seed are to be segregated by

variety. The use of belt or pneumatic conveyors is therefore desirable if any appreciable

quantity of seed is to be saved for planting.

Where vertical lifts are employed, screw

elevators are generally satisfactory. In some

instances seed may be conveyed by belts or

low-pressure piping. Conveying seed by air in

small pipes is now the general practice

(Bennett and Franks 1948).

NOT DRAWN TO SCALE

FIGURE 4-17.—SmaU-pipe system for conveying cottonseed, A, 16-mesh air filter, or screen box. B, Rotary

positive-pressure blower. C, Dropper, or vacuumwheel feeder, with eight or more shallow pockets.

D, Gin-stand seed belt. E, Long-sweep, large-radius

elbows. F, Valve for diverting seed to bin or

storage. G, Six-bolt flange and rubber gasket.

H, Funnel discharge for efficient delivery. (Diameter at d may be 4 to 8 inches.)

Materials handling is a highly specialized

enterprise. Its procedures and details have

developed largely from usage and experience

in cotton gins. Large installations should be

designed and installed by a materials-handling

engineer. Smaller, less involved installations

can be designed and installed by local mechanics

or by plant supervisors and engineers.

Small-pipe systems are economical to operate

and relatively trouble-free. They enable the

cotton producer and ginner to maintain pure

varieties of cottonseed because the apparatus

is self-cleaning. They have adequate capacity

for moving as much as 500 pounds of seed per

minute, as fast as the cotton is ginned. They

may also be used for carrying seed to storage

bins and for moving it later for grading, sterilizing, and other processes at rates to suit

plant capacity. Cottonseed has been successfully

handled by small-pipe blowing systems for distances up to 700 feet at operating costs lower

than larger pipe and fan methods.

A small-pipe system is shown in figure 4-17.

A self-cleaning seed belt is used to feed the

system dropper that introduces the seed into

the air pipe. A valve enables the operator to

divert the seed to truck bin or to storage, and

flanged piping and elbows provide the piping

runs to points of delivery.

AIR-CONVEYING PRINCIPLES AND

CALCULATIONS

Pipes 4 to 8 inches in diameter have proved

large enough for handling cottonseed in gins

and delinting plants. Table 4-11 gives the seedhandling capacity of such pipes.

For preliminary calculations to determine

total resistance pressures that the pump must

overcome, it is customary to allow 16 ounces of

TABLE 4-11.—Cottonseed handling aapacities of

different diameter pipes

Pipe

diameter

(inches)

Volume

of airi

(ftVmin)

Capacity2

Lb/min Tons/h Bales/h

4 436 128 3.8 9.6

5 682 200 6.0 15.0

6 982 288 8.6 21.6

8 1,745 512 15.4 38.4

1 Based on a velocity of 5,000 ft/min.

2 Based on 800 lb of seed per bale.

69
resistance (or 1 pound per square inch) for

each 200 linear feet of piping. In calculating,

each short elbow and each valve must be considered equivalent to approximately 15 feet of

straight pipe. For a more accurate estimate on

which the factory can provide the blower unit

and suggest its speed, the pressure losses for

the individual elements that make up the

system may be estimated as follows:

Estimated pressure

loss in ounces

per square inch

4-inch piping, each 100 feet 6.0

5-inch piping, each 100 feet 5.0

6-inch piping, each 100 feet 3.0

8-inch piping, each 100 feet 2.0

For both 4- and 5-inch pipes :

Elbows .8

Base and tapered discharges

from dropper 2.0

Cyclone collector and sacker

at end of pipe 1.0

For both 6- and 8-inch pipes :

Elbows .5

Base and tapered discharges

from dropper 2.0

Cyclone collector and sacker

at end of pipe 1.0

Average air velocities in small seed pipes are

in the range 4,200 to 5,200 feet per minute, with

5,000 feet per minute as the common figure.

Air volumes of about 4 cubic feet per pound of

cottonseed have been used in short piping systems with an air pump, but it is advisable to

allow 5 cubic feet where pipe length exceeds

250 feet.

For horizontal blowing of cottonseed, the air

velocity in the pipe should not be less than 4,000

feet per minute. No seed should pass through

the blower.

BLOWERS

Since the operating air pressure range for

small-pipe systems is usually 1 to 4 pounds per

square inch, the two-lobe rotary air pump (fig.

4-18) is the type most commonly used; it is

known in the trade as a positive-pressure

blower. These blowers can purge the piping to

overcome minor chokages by a temporary

increase in air pressure.

Performance data for the rotary positivepressure blowers now being used successfully

at cotton gins and seed establishments are given

in table 4-12.

A screened intake or air filter is imperative

on cottonseed-handling blowers to protect the

lobes and casing from excessive wear. Screenedintake filters may be either factory built or

homemade. Large areas of close-mesh bronze

screen wire are necessary for homemade intake

filters; these filters should have at least 5

square feet of gross screen area, all accessible

for daily or more frequent cleanings.

Relief valves are seldom used on positivepressure blowers because they prevent purging

the system at higher pressures when chokages

threaten. If used, they should be set to pop off

(release) at double the working pressures.

FEEDING SEED INTO PRESSURE PIPES

Cottonseed may be satisfactorily fed into a

small-pipe pressure system by means of a

dropper, or rotary sealed wheel (sometimes

called a vacuum wheel), that mechanically

drops the seed into the air line on the discharge

side of the pump or blower. "Seed plugs" of

the auger type have also been used successfully.

Speeds of the rotary sealed wheel, or dropper,

should be relatively low—30 to 60 revolutions

per minute—and internal seals at the ends and

pocket divisions are necessary to prevent serious air leakage. It is customary to provide an

independent drive for the hopper, because its

speed is much slower than that of a rotary

positive-pressure blower. A taper of 20 inches

or more should be used on feeder base outlets

or jet boxes to prevent chokage. Jet boxes must

be set as close to the feeder as possible.

FIGURE 4-18.—Cross section of a typical positive-pressure two-lobe rotary air pump used for conveying

cottonseed. Rotation may be reversed if desired.

70
?s

Q)

«S

^1

111111111 *^. *^ *^

CM

1111i1111•••

00 Tl«O

m2O

(M CO '^

1^

^

Xi

>>cr

^

11

OOO

llllllll^OíN

S^^ ^^ co^ o^

03 4-3 TH TH

W

Ô «H .

4-3

<H

S

o

eu^

o

lO

bû

O (N C^ -^ iÄ C5 00 (N THIII

^

CO .S PQ

S

TH TH^ TH (N (M (M ;::5

^^ Xi

o

*^

o

CO 11 l>C<IOTt<çOÇOiAOO

Oí o

CÖ

4^ rO rHOSlAÇDOiCDt-OOl 1 1

p>^ ft ;;;- (M(MIOTJ<IO00TH^'^íI>^ CO ^

Qi ^

r-T TH TH

bß

O

HOO

1

«1

(NC0t>O5t>'rl<|11111

ID

1

g

lô CO ai 00O Tiî

g Î3

wS TH TH . be

5â

CO

CO

o

ri:: £.S

2

PH CO ^91*1 00 Ti< (M 00

o a> ...

«H -P O

(NOCOt-iHt^l11111

(N CO lO -^^ 00

'S .S

so

COo

si

i^ íJ:5COI>THCOI>OOOOOOO <ü

O

^ be

.s

cô'^çDçoi>cî(Niot>'<**r>o

? CO

soo

M2O

TH iH iH TH TH (N

o <M 4J

C

11 0(NOrHCO<MlOOOOOO

^ cô

¿^

LOCOOiTHTfTH(N>üOiO(NOOÍ>

r-T TH r-T TH TH CÎ

*i .s

^ ¿s

1

s1

.s«

g

05 CO Ç£> (M. 00 (N TÍJ LC5q111

bû THC^C0CÔcÔiAîlîl>C5 ^i

O

^

M2

^ Iß ^^-^ ^0 o w ^^

û.

,i5

^9

n3

«'S

1i

(NOOCOlOt-çDlAOO,,,

4-3

1^

Ü ^•G OiCOiMlOOOLOt-OlO 1 1 1 cá o o

CQ -p

<MCOCOIOÇDC5(NIOI>

r-T TH TH

3 %1

4

ÇJ <+H

P

iS LOOOl^OkÄOOOOOO >> . >> c3 P 53 bû o fi c <

t-oïOOt-a>c<ioo(Mooi2

lOÇ£)Oli5<^0:)C<l'^ÇDOC^"^ Vp T3 *4J

H

m %^ iH TH TH TH TH TH r-T C« 0) CQ

1^&

13

Í3

'^ Il

PH 'TJ rr-! >>

T^ IÄ Ç£> 00

W 0)

P .tí

lO t> I>O

O)

4-3

rto^

^ PH ft _ Í-H o

NO TH iH rH <M 2^S

t/2 iz; CD t' t> 00

«H

^9

O JAOO

3 -s "g

s

73 -^ --5

o t- ino ft

*« fi a, 2. fi

SSS

iH TH (M lO

a

553 -S 13

C <H 4J

<ío rji <IÍ

O N_^

ft PH ft ft -^ c.

mf 1 P Í2 P t:^

71
PIPING

Aluminum is the most commonly used piping

material, but standard 20-gage galvanized pipe

or galvanized lightweight tubing may be used

where the piping is to be exposed to the

weather. Joints should be flanged wherever

seed passes through the pipe. Six-bolt companion flanges with rubber gaskets are recommended. On the blower intake and discharge,

or at points ahead of the seed dropper, standard

threaded pipe and fittings can be used for

handling the compressed air.

Seed-handling elbows should be 18 gage or

heavier and must be of the long sweep type

to give satisfactory service without chokage.

A 36-inch radius is recommended for pipes 4,

5, and 6 inches in diameter, and a 48-inch

radius for pipes 8 inches in diameter.

Risers, or lifts, in seed piping should preferably be on an incline rather than vertical,

both to keep the angles at elbows as large as

possible and to save the piping length that

diagonals afford in comparison with right-angle

runs.

Pipe should not be allowed to slope downward

in the direction of flow. Downward slopes may

cause chokages.

VALVES, BRANCHES, AND DISCHARGES

Valves for small-pipe systems frequently

give trouble in operation unless they are of

good workmanship and are well fitted for tightness. Not more than two valves should be used

in the ordinary cottonseed system, because

leakage and careless adjustments invite trouble.

For lines containing vane-type seed valves,

the takeoff angle should not exceed 30°. The

deflector vane should be of adequate thickness

and should be well fitted into the body of the

valve, with the seated end adjusted to prevent

seed chokage by lint or by seed build-up at the

valve intake.

The discharge funnel (fig. 4-17, H) materially assists airflow through the pipe to open

bins, but it should not be directed at a wall or

any obstacle that might cause the seed to crack.

Cyclone collectors of seed for delivery to

sackers may be used at the ends of small-pipe

systems. The downspouts from these collectors

should be 8 inches or more in diameter to

prevent choking or bridging of seed at their

bases.

OTHER FEATURES OF SMALL-PIPE

SYSTEMS

Approximate distances for conveying cottonseed efficiently with small-pipe systems are

200 to 700 feet of piping. Since no two systems

are exactly alike in length and number of

risers and elbows, the limitations of pressure

and volume peculiar to the type of blower must

be carefully considered in the design of any

small-pipe system.

Power cost is usually about half that of

ordinary cotton-gin fan systems. Initial cost

of small-pipe systems using positive-pressure

blowers is somewhat lower than that of the gin

fan system.

The efficiency of the small-pipe handling

system depends on correct installation.

MEASURING EQUIPMENT

Most modern gins are equipped with devices

for measuring cottonseed from each bale before

or during its discharge into the conveying system. A common type of cottonseed measuring

device consists of a pocket wheel that receives

the seed from the gins and dumps automatically

when each succeeding pocket of the wheel has

received a specified amount of seed. Depending

on the size of the unit, each 10 or 20 pounds

of seed is measured as it is dumped, and the

device can be equipped to signal the completion

of each bale.

REFERENCE

Bennett, C. A., and Franks, G. N. 1948. Cottonseed

handling with small air pipes. U.S. Dep. Agrie. Cire.

768, 8 pp.

Cottonseed Aeration and Storage

By L. L. SMITH and S. T. RAYBURN, JR.

Mechanical harvesting and modern highcapacity gins have increased the need for bulk

storage of cottonseed. In recent years more

and more emphasis has been placed on maintenance of cottonseed quality, for both planting

and oil mill purposes. Aeration systems are

now being made to engineering designs rather

than by trial and error, helping to reduce seed

losses. Properly designed aeration systems help

prevent free fatty acid formation and maintain

initial seed viability. With improved system de72
signs, selection of proper equipment, and good

operating procedures, cottonseed quality can

be maintained efficiently and effectively.

STORAGE

Most of the cottonseed from the ginning

process goes into storage either for oil mill

processing or for planting. A small amount will

be returned to the farm for cattle feed. Approximately 5 million tons of cottonseed were

produced in the United States in 1973, of which

about 4 percent (197,600 tons) was stored and

processed for planting. The remainder was

used primarily in the milling industry. Storage

methods are similar for preserving quality for

either purpose. Proper aeration is the key to

minimizing storage losses and quality deterioration. Storage methods vary in different

geographic areas.

Mechanically harvested cotton when ginned

may have a seed moisture content (wet basis)

as low as 6 percent and as high as 18 percent,

with the majority within the range of 10 to 15

percent. These moisture contents, in most storage areas, present no problems for safe storage

with proper aeration and cooling. However,

cottonseed for planting purposes should not go

into storage with a moisture content above 12

percent.

The highest moisture content in seed will

usually occur at the beginning of the harvest

season. Most ginners and storage warehousemen, at the beginning of the season, will

exercise their prerogative of sending this highmoisture seed to the oil mill. The drier seed

will go into storage for planting-seed processing

later in the year.

Most present-day cottonseed storages have

moisture-proof concrete floors. The structural

framing may be either wood or steel, with the

outside clad with sheet steel. Some plantingseed storages may have walls faced on the inside. Facing gives some protection from extreme

temperature changes that may occur in steelclad buildings. However, cottonseed is a good

insulator and wide temperature changes occur

only in a relatively thin layer along the walls.

Cottonseed storage capacities may range

from 400 to several thousand tons. In computing storage capacity, a density of 80 cubic feet

per ton is used for seed depths of 24 feet or

less. A density of 75 cubic feet per ton is

used for depths of 24 to 50 feet. For depths of

50 feet or more, a density of 70 cubic feet per

ton is used. Table 4-13 gives the capacities of

shallow, flat storages with depths to 24 feet,

commonly used for planting seed.

Calculating the capacities of Muskogee-type

(deep, peaked) storages is more complicated

than calculating for shallow, flat storages. Following is an equation for computing the approximate capacities of Muskogee-type storages

using the assumptions given:

1. All roof slopes are 45°.

2. Head house is 10 feet wide.

3. Any space lost to aeration system, filling

and unloading systems (tunnel etc.) and

internal building structural losses is disregarded.

4. House is filled to the roof.

5. All dimensions are inside building.

6. Density is 70 cubic feet per ton for tightly

packed seed over 50 feet deep.

Calculate as follows:

Volume in ît^ = WL{S + H)-HHL + W-l.SSSH),

volume in ft"^

Capacity in tons= 70 ftVton *

where S=sidewall depth (feet),

/i=maximum depth of seed less depth

of sidewall (feet),

L=length of storage (feet),

and TF=width of storage (feet).

AERATION AND COOLING

One difficulty encountered in the past in

designing aeration systems for moving small

amounts of air through stored cottonseed was

the lack of information on the resistance that

cottonseed offers to air flowing through it.

Research in recent years has established some

values for static pressure losses or resistance

to airflow by cottonseed at depths of 10 to 80

feet and airflow rates of 2 to 20 cubic feet per

minute per ton of seed. Table 4-14 gives some

comparative values for three depths and three

airflow rates and the resulting static pressures

and approximate horsepower requirements. Additional static pressure values and horsepower

requirements at various depths are given in

USDA Marketing Research Report No. 1020,

''Aeration of Cottonseed in Storage."

An airflow rate not less than 10 cubic feet

per minute per ton is recommended for cotton

planting seed. At this rate, cottonseed having

12 percent moisture can be cooled sufficiently

with ambient air to maintain seed quality.

73
Many certified seed producers use an airflow

rate of 15 cubic feet per minute per ton. However, at this rate, the static pressure is approximately 65 percent greater and the horsepower

requirement increases by about 140 percent

over that for 10 cubic feet per minute per ton.

Research results indicate that 10 cubic feet

per minute per ton is sufficient to cool cottonseed to not less than 50° F, as recommended

for planting seed.

In large Muskogee-type storages for oil mill

processing, the depth of the cottonseed usually

is a limiting factor in the amount of air that

can be moved economically. For example, with

cottonseed 80 feet deep and an airflow rate of

2 cubic feet per minute per ton, the static

TABLE 4-13.—Capacities of flat cottonseed storages

^ ,, Capacity

Inside p^r

width T /. .

Average

depth

of seed

Capacity in tons when length of house in feet is—

vviuLii linear foot

(f^^^) (tons)

80 100 120 140 160 180 200

(feet)

4.50 12 360 450 540 630 720 810 900

5.25 14 420 525 630 735 840 945 1,050

6.00 16 480 600 720 840 960 1,080 1,200

30 / 6.75 18 540 675 810 945 1,080 1,215 1,350

7.50 20 600 750 900 1,050 1,200 1,350 1,500

8.25 22 660 825 990 1,155 1,320 1,485 1,650

9.00 24 720 900 1,080 1,260 1,440 1,620 1,800

5.40 12 432 540 648 756 864 972 1,080

6.30 14 504 630 756 882 1,008 1,134 1,260

7.20 16 576 720 864 1,008 1,152 1,296 1,440

36 \ 8.10 18 648 810 972 1,134 1,296 1,458 1,620

9.00 20 720 900 1,080 1,260 1,440 1,620 1,800

9.90 22 792 990 1,188 1,386 1,584 1,782 1,980

10.80 24 864 1,080 1,296 1,512 1,728 1,944 2,160

6.00 12 480 600 720 840 960 1,080 1,200

7.00 14 560 700 840 980 1,120 1,260 1,400

8.00 16 640 800 960 1,120 1,280 1,440 1,600

40 / 9.00 18 720 900 1,080 1,260 1,440 1,620 1,800

10.00 20 800 1,000 1,200 1,400 1,600 1,800 2,000

11.00 22 880 1,100 1,320 1,540 1,760 1,980 2,200

12.00 24 960 1,200 1,440 1,680 1,920 2,160 2,400

/ 6.75 12 540 675 810 945 1,080 1,215 1,350

I 7.87 14 630 787 945 1,102 1,260 1,417 1,575

] 9.00 16 720 900 1,080 1,260 1,440 1,620 1,800

45 < 10.12 18 810 1,012 1,215 1,417 1,620 1,822 2,025

11.25 20 900 1,125 1,350 1,575 1,800 2,025 2,250

12.37 22 900 1,237 1,485 1,732 1,980 2,227 2,475

13.50 24 1,080 1,350 1,620 1,890 2,160 2,430 2,700

7.50 12 600 750 900 1,050 1,200 1,350 1,500

8.75 14 700 875 1,050 1,225 1,400 1,575 1,750

10.00 16 800 1,000 1,200 1,400 1,600 1,800 2,000

50 < 11.25 18 900 1,125 1,350 1,575 1,800 2,025 2,250

12.50 20 1,000 1,250 1,500 1,750 2,000 2,250 2,500

13.75 22 1,100 1,375 1,650 1,925 2,200 2,475 2,750

15.00 24 1,200 1,500 1,800 2,100 2,400 2,700 3,000

9.00 12 720 900 1,080 1,260 1,440 1,620 1,800

10.50 14 840 1,050 1,260 1,470 1,680 1,890 2,100

12.00 16 960 1,200 1,440 1,680 1,920 2,160 2,400

60 { 13.50 18 1,080 1,350 1,620 1,890 2,160 2,430 2,700

15.00 20 1,200 1,500 1,800 2,100 2,400 2,700 3,000

16.50 22 1,320 1,650 1,980 2,310 2,640 2,970 3,300

18.00 24 1,440 1,800 2,160 2,520 2,880 3,240 3,600

74
pressure is approximately 20 inches (water

gage), as given in figure 4-19. Research results

also indicate that this airflow rate is sufficient

to cool cottonseed 80 feet deep to temperatures

of 40° to 45° F by late December or January.

Usually no additional aeration is necessary

once the seed has been cooled to the desired

temperature. Even so, seed temperatures should

be monitored throughout the storage period,

especially in planting seed, since hot spots occasionally develop. Usually a few hours of

additional aeration will remove the heat from

the trouble spot, provided it is discovered

promptly.

Many planting-seed storages use commercially

available systems for monitoring temperatures

of stored cottonseed. Systems using thermocouples are probably the most common. Thermocouple cables can usually be fastened to some

part of the roof or truss structure and suspended to near the floor. A breakaway cable hanger

is recommended to prevent structural damage

to the building in case of excessive force on

the cable caused by seed settling. The sensing

points in each cable may be spaced 3, 4, or 5

feet apart, depending on the depth of seed and

the number of sensing points desired. The

distance between horizontal cables is optional,

but is usually 20 feet in each direction

lengthwise and crosswise of the storage.

Measuring temperatures in deep-stored cottonseed is much more difficult. Thermocouple

cables are sometimes used by placing them in

the cottonseed horizontally during the filling

process; these cables will tend to shift with the

TABLE 4-14.—Resistance of cottonseed to airflow at specified rates of flow and depth of

seed in level storage

Depth of

cottonseed

(feet)

Airflow

rate

(ftVmin/ton)

Static

pressure

(inH.O)

Horsepower

required

per 1,000 tons

20

30

40

5

10

15

5

10

15

5

10

15

2.8

6.4

10.6

6.5

15.8

26.5

12.3

30.5

52.5

3.5

19.0

43.0

10.0

42.5

100.0

17.0

86.0

210.0

seed and make it difficult to determine where

the sensing points are located. Another common

method is to drive a pipe or heavy conduit

vertically into the cottonseed at selected locations and hang mercury thermometers, tied to

a heavy cord at desired intervals, inside the

pipe or conduit. When temperature readings

are needed, the cord is rapidly removed from

the pipe and each thermometer read as it is

removed. When all thermometers have been

read and the temperatures recorded, the

thermometers are returned to place and left

until the next reading time. This method will

give a reasonable estimate of the temperatures

in the seed surrounding the pipes.

Aeration system designs fall into two general

types, manifold and central duct. The manifold

system has several aeration ducts spaced on

the floor and connected to a fan. This type of

system makes it possible to select sections or

combinations of sections of the storage to be

aerated at any one time, since each aeration

duct is provided with a gate or slide valve that

can be opened or closed as needed. The centralduct system has one or two large aeration ducts

in or near the center of the storage, lengthwise

of the building. A supply pipe from the center

of the central duct connects to a fan outside

the building. In most central-duct systems, the

unloading tunnel is covered with perforated

metal or some other material that will enable

50 55 60 65

COTTONSEED DEPTH -

70

FEET

FIGURE 4-19.—Fan horsepower and static pressure requirements for aerating cottonseed at three airflow

rates at depths ranging from 45 to 80 feet.

75
it to serve as part of the aeration duct. With

this type of system, aeration may be restricted

to that time when the tunnel is covered with

cottonseed. Additional aeration ceases once the

tunnel is uncovered for moving seed out of the

storage.

DESIGN OF AERATION SYSTEMS

Most aeration systems have these principal

parts: (1) one or more fans to supply the

required volume of air at a specified static

pressure, (2) ducts to move the air into or out

of the cottonseed, (3) supply pipes to connect

the fans and ducts, and (4) a motor to drive

the fan.

The primary factors that influence design of

a system and selection of aeration equipment

are (1) the size and type of structure in which

the system is to be installed, (2) the depth of

cottonseed through which the air will be moved,

(3) the airflow rate per cubic foot (or per ton)

to be provided, and (4) the quantity of seed

to be served by each fan.

After these points have been settled, the

following may be determined: (1) total air

volume to be supplied, (2) the static pressure

against which the fan must operate, (8) the

type and size of fans and motors, and (4) the

type and size of,aeration ducts and supply pipes.

Most aeration systems are designed with the

airflow downward through the cottonseed.

Downward airflow eliminates moisture condensation and accumulation in the top layers of

cottonseed, which can occur when warm, moist

air moves upward into the cold top layers of

seed. Downward airflow also counteracts any

convectional air movement that might take

place. In addition, temperature and odor of the

exhaust air from the fan can give some indication of seed quality to the experienced

warehouse operator.

Airflow rates used herein are based on research reported in USDA Marketing Research

Report No. 1020. In designing an aeration

system it should be recognized that uniformity

of airflow is impossible to achieve in most

aerated storages, especially in Muskogee-type

or peak-loaded storages where seed depths may

vary from 10 feet at the sidewalls to 100 feet

or more at the peak of the mass. Since air

moves along the path of least resistance, the

ducting should be so designed to equalize the

air paths as nearly as possible and to assure

10 15 20 25 30 35

COTTONSEED DEPTH - FEET

FIGURE 4-20.—Fan horsepower and static pressure

requirements for aerating cottonseed at various

airflow rates and at cottonseed depths from 10 to

40 feet.

at least the desired airflow through the seed

at all locations.

The following design criteria are used in

selecting the aeration ducts, supply pipes, fan

sizes, and motor sizes. To determine the required aeration-duct surface area, a velocity

of 10 to 20 feet per minute at the duct surface

is assumed. To calculate supply-pipe sizes, an

air velocity of 1,500 to 2,000 feet per minute is

used, except that a velocity of 2,500 feet per

minute is permissible in short pipes (5 to 10

feet in length). Fan sizes are determined by

the total amount of air each fan is to deliver

and the static pressure, depending on the airflow rate and depth of seed (figs. 4-19 and

4-20). The approximate horsepower required

for each fan can also be estimated from figures

4-19 and 4-20, once the airflow rate and cottonseed depth are known. Fan manufacturers'

capacity tables will give the horsepower required for their fans under specific conditions.

76
J!==!t

r_^

r/-6' , , iT-e' u&m140'-0'

ir-6' >, ir-6'

"^

8^

^^

0 36" DiA. H.R. CORRUGATED

PERFORATED AERATION ÖOCT

(D 36: DtA. KR CORRUGATED

SOLID supply DUCT

(C) 12" DIA_ PIPE

(D) 18" D(A. RPE

0 24" D(A. RPE

0 TRANSIKJH FROM itf DIA.

TO 24" DÍA. PIPE

0 TO FIT FAN

® GATE VftLVE

FIGURE 4-21.—Plan view of aeration layout in a flat storage.

SIDE VIEW INSIDE END VIEW INSIDE

0 0

b

X \ \ / / X. V.

AD 0 à) 0-^

0--U

0 32" DIA. SUPPiy RPE

0 TUNNEL DOOR

0 TRAN9TI0N TO FIT FAN

0 TUNNEL COVERED WITH PERFORATED METAL

0 TUNNEL COVERED WITH SOLID METAL

SCALE IN FEET

0 10 20 30 40 50

FIGURE 4-22.—Aeration layout of a Muskogee-type, or peak-loaded, storage.

77
For example, figure 4-21 is a flat storage

for planting seed, 60 feet wide and 140 feet

long, with cottonseed 16 feet deep. The capacity

of this storage is 1,680 tons at density of 80

cubic feet per ton. Using a design airflow rate

of 10 cubic feet per minute per ton, the total

volume of air required is 16,800 cubic feet per

minute. The amount of aeration-duct surface

area required, using an air velocity at the duct

surface of 10 feet per minute, is 1,680 square

feet. Any combination of duct diameters and

lengths that provides this amount of area would

be satisfactory. The distance between ducts on

the floor should not be greater than l^/^ times

the cottonseed depth. In this storage 36-inchdiameter, half-round, perforated, corrugated

ducts were selected. All ducts are 24 feet long

and spaced 17.5 feet apart on the floor (fig.

4-21).

With this system, either two or four fans

manifolded on each side of the building may be

used. Using two fans, each is required to deliver

8,400 cubic feet per minute. The static pressure against which the fans must operate,

determined from figure 4-20, for a depth of

16 feet at an airflow of 10 cubic feet per minute

per ton is approximately 3.9 inches (water

gage). The horsepower required (fig. 4-20)

is approximately 1.2 per 100 tons, or 10 horsepower per fan using two fans. Whether using

two or four fans, the static pressure that the

fans will operate against is the same—3.9

inches (water gage). Using four fans, each fan

will be required to deliver only one-half the

volume required when using two fans.

In designing an aeration system for a Muskogee-type or peak-loaded storage, the same calculations are used as for the flat storage.

Figure 4-22 illustrates a storage 120 by 150

feet, with 20-foot sidewalls and cottonseed to

a maximum depth of 75 feet. The capacity of

this storage is approximately 11,000 tons,

calculated as above. Because of the cottonseed

depth and the static pressures and horsepower

requirements, the system in this storage is

designed to deliver 2 cubic feet per minute per

ton. The total required volume of air is 22,000

cubic feet per minute at a static pressure of

approximately 17.5 inches (water gage) (fig.

4-19). One or two fans may be used; two are

used in this design. Each fan is required to

deliver 11,000 cubic feet per minute at 17.5

inches (water gage) of pressure and will require approximately 50 horsepower. The center

90 feet of the unloading tunnel is used as the

aeration duct. This part of the tunnel is covered

with perforated or expanded metal to allow

airflow through it. Tunnel doors provide for

starting aeration as soon as the center portion

of the tunnel is covered with seed. Thirty feet

on either end of the tunnel are sealed against

any air movement to eliminate short-circuiting

of the air through the shallow seed directly over

the tunnel near the outside wall.

TYPES OF FANS

The most commonly used fans for aerating

cottonseed are of the centrifugal (radial flow)

type. Propeller (axial flow) fans may be used

where the static pressure is not more than 3 or

4 inches (water gage). Centrifugal fans must

be used to aerate deep storages.

Three types of centrifugal fans are shown

in figure 4-23. The forward-curve fan has a

large number of blades and operates at relatively low speed. One disadvantage of this fan

is that the motor may be overloaded if the

static pressure is decreased, causing an increase

in air delivery; it is not commonly used for

aerating cottonseed when the motor load will

vary considerably between the beginning of the

season, with a partially filled storage, and the

end of the season, when the storage is full.

The backward-curve centrifugal fan is a

high-speed fan that usually has 12 blades. It

is slightly more efficient than a forward-curve

or straight-blade fan. One of its advantages is

a self-limiting horsepower characteristic; when

used near the point of maximum efficiency with

a motor of adequate size, there is no danger

of motor overload.

A centrifugal fan with straight blades, sometimes called a pressure fan, or, more commonly,

an industrial exhauster, is widely used in aerating cottonseed. It has some overloading characteristics when the static pressure is reduced,

but will not overload as much as a forwardcurve fan. A slide gate or damper placed in

the supply pipe leading to the fan can be adjusted to maintain a relatively constant static

pressure on this fan, as the amount of cottonseed varies.

Three types of axial flow fans are shown in

figure 4-15. Basically, they are low-pressure

fans, but certain designs are suitable for up to

medium-pressure operation.

78
Centrifugal fan consisting

of a fan rotor or wheel within a scroll

tjpe of housing. It is designed to

move air over a wide range of volnmes and pressures (up to 15 inches

of water and above). The fan wheel

maj be equipped with radial tip

blades or three other tjrpes.

A. Fan whed equipped with forward-carve lip blade.

B. Fan wheel equipped with backward>curve tip blade.

C. Fan wheel equipped with straighttip blade.

PN-5242

FIGURE 4-23.—Centrifugal fans showing various type wheels.

The centaxial fan (fig. 4-24), relatively new

in design, is being used in some of the latest

aeration systems. The combination design has

the characteristics of both the basic axial and

centrifugal fans. The housing is cylindrical

with a venturi inlet and guide vanes at the

discharge. The impeller has airfoil blades that

combine the characteristics of the airfoil propeller fan and the back-curved centrifugal fan.

It has a low noise level and is nonoverloading.

This fan offers the installation simplicity of an

axial flow design and the performance of the

centrifugal. Its efficiency is very good, and it

will perform in pressure ranges of up to 17

inches (water gage) at relatively low speeds.

Fans should be selected on the basis of performance ratings supplied by the manufacturers. A performance rating specifies the

volume of air delivered by the fan at various

static pressures. Reliable performance ratings

are assured if the fans have been rated in

accordance with the testing code of the Air

Moving and Conditioning Association.

HANDLING PLANTING COTTONSEED

Cottonseed to be used for planting requires

some additional consideration during storage.

79
PN 5243

FIGURE 4-24.—Centaxial fan with airfoil blades. It will

move air through a wide range of volume at pressures up to 16 inches of water while operating at

relatively low speeds.

Seed from mechanically harvested cotton will

usually go into bulk storage without any additional cleaning at a moisture content of 12

percent or less. It may be conveyed into storage

by mechanical methods with a belt or screw

conveyor or pneumatic system. Less damage

will occur to the cottonseed in a belt conveyor

than in either of the other two methods. To

minimize seed damage in a pneumatic conveyor,

all interior pipe surfaces should be as smooth

as possible. Impact damage can be kept low

by making all pipe turns with a radius of at

least 4 feet.

The nonflowing characteristics of cottonseed

causes a major problem in moving it out of

storage. Considerable hand labor in conjunction with portable conveyors is used. Pneumatic

removal is being used in some storages. In most

of these cases, however, the size and weight of

the suction pipes are so great that very little if

any reduction in labor is realized.

Collection and Disposal of Gin Waste

By OLIVER L. MCCASKILL, R. V. BAKER, and

R. A. WESLEY

In the research program of the U.S. Department of Agriculture, an effort is made to

anticipate the future needs of the ginning industry. Currently, one of the most pressing

needs is for air-pollution abatement equipment

for waste collection and disposal. This need has

been in the forefront since the passage of the

Federal Clean Air Act of 1970.

TREATING AND DELINTING

COTTONSEED

Processing and treating of planting seed will

start after the harvest season, usually in December. The cottonseed will be moved from the

storage and into the processing plant where

it will be cleaned. After cleaning, it may be

delinted by one of several processes. The best

planting methods require a delinted seed that

can be planted with precision accuracy.

Several methods for delinting cottonseed are

in use. In machine delinting, the cottonseed is

reginned to remove some additional linters

from the original ginned cottonseed. Following

machine delinting, flame delinting may be used

to remove additional linters and fuzziness and

helps to make the seeds flow more easily. Close

machine delinting removes more of the linters

than either of the above two methods. Acid

delinting has gained popularity in recent years,

because it removes all linters, leaving the black

seed, which will flow like grain. The most

precise planting control in existing planters

can be obtained with acid-delinted seed. Since

acid-delinted seed cannot be stored as long as

seed delinted by other methods, acid delinting is

usually done as near planting time as possible.

After the cottonseed has been delinted, it is

treated with the necessary chemicals to protect

seed viability and to reduce bacterial activity

in the soil during the early growing stages of

the plant. The treated seed is bagged, labeled,

and stored for distribution and sale. Because of

the controls and precautions necessary in the

treatment and delinting processes, most planting seed is processed in commercial seed

facilities.

At most gin plants, the only pollutant emitted

into the atmosphere is particulate matter, either

exhausted directly into the atmosphere or escaping from some type of abatement equipment.

Additional pollutants in the form of smoke and

fly ash are emitted from gin plants that incinerate the collected waste material. At the

present time, all cotton-producing States are

operating under some form of process-weight

standard having an allowable emission level

based on the total weight of material being

processed.

80
The actual levels of gin emissions vary, depending on the time and method of harvest.

During the 1973-74 cotton-harvesting season,

63 percent of the crop was machine-picked and

36 percent was machine-stripped. The amount

of foreign matter removed by gin equipment

is quite variable, ranging from an average low

of 107 pounds per bale for hand-picked cotton

to an average high of 740 pounds per bale for

machine-stripped cotton (table 4-15).

The conveying systems in modern cotton gins

are predominantly pneumatic and require large

volumes of air to move the cotton through the

processing sequence. A gin with a capacity of

12 to 15 bales per hour requires approximately

100,000 cubic feet of air per minute to operate

properly. Trash removed from the seed cotton

by the gin's cleaning equipment is usually carried out of the gin by these pneumatic systems.

The ginner's waste problem is twofold. First,

he must collect the material, and second, he

must dispose of it. Both operations must be

performed without causing excessive air

pollution.

HIGH-EFFICIENCY CYCLONES

Cyclones, the most widely used collection

equipment on high-pressure discharges, collect

the bulk of the waste being discharged. Cyclones

are used extensively because they are effective,

inexpensive, and require little maintenance.

They are essentially cylindrical, with a long.

TABLE 4-15.—Average weight of foreign matter removed during ginning a 500-pound

bale (gross iveight) from cotton harvested

by various methods

Method of harvest

100

Hand- Machine- Machine- Handpicked picked stripped snapped

Percentage

of cropi <0.5 63 36 <0.5

Av. waste weight,

lb2 107 203 740 615

1 Percentages from "Charges for Ginning Cotton,

Costs of Selected Services Incident to Marketing, and

Related Information, Season 1973--74," U.S. Dep.

Agrie, Econ. Res. Serv. [Rep.] ERS-2, August 1974.

2 Averages calculated from seed-cotton weights, using

the seed-lint ratio furnished by cotton breeders and correcting it for 3 percent seed-cotton moisture removal

during ginning. Weighted waste averaged for the crop :

322 pounds per bale.

« 80 -

<4 <8 <I2 <I6 <20

PARTICLE SIZE (micrometers)

<24

FIGURE 4-25.—Percentage of various sizes of gin trash

particles emitted from exhaust of a small-diameter

cyclone.

CYCLONE DESIGN PROPORTIONS

Bc= ^oA

«C = ^0/2

DE= ^O/Z

Sc= Dc/é

Zc= 2Dc

Jç = 12" MINIMUM

FIGURE 4-26.—Relative dimensions for a small-diameter

design cyclone.

81
conical hopper bottom and a center cylinder

through which the air escapes. The trash-laden

air enters tangentially near the top. Centrifugal

force caused by the whirling action of the

trash and air pushes the trash outward and

into the conical hopper below. The air passes

up and out through the center cylinder.

A properly sized high-efficiency cyclone collects 99.9 percent of the total trash introduced

and virtually 100 percent of the trash that is

larger than 30 micrometers in diameter (fig.

4-25) (Wesley et al. 1972).

Cyclone size and arrangement depend on

several variables, the most important of which

is the volume of air to be handled. This can be

TOP VIEW

DUAL

TANDEM

measured by the use of a pitot tube and

manometer. In general, low-volume fans require only a single cyclone installation; however, as air volume is increased, two to four

parallel-mounted cyclones are required to insure

high efficiency and keep the sizes within practical limits. A diameter of 34 inches is considered optimum. Figure 4-26 illustrates

relative dimensions for small-diameter cyclone

designs. Table 4-16 is a guide to the selection

of cyclone size and arrangement based on air

volume, and figures 4-27, 4-28, and 4-29

illustrate typical cyclone arrangements.

TOP VIEW

SPREADER IN TOP

=P—^ =P-^

FRONT VIEW

FIGURE 4-27.—Double cyclone arrangement.

FRONT VIEW

FIGURE 4-28.—Triple cyclone arrangement.

82
The pressure resistance the fan is capable of

overcoming is another important item in cyclone sizing. A minimum inlet air velocity of

3,000 feet per minute is recommended for efficient removal of the trash and dust. The

calculated pressure drop in cyclones designed

for an inlet air velocity of 3,000 feet per minute

is 4.3 inches of water, which is within the

normal operational limits of straight-blade

centrifugal fans.

Figure 4-30 shows the optimum velocity

range for operating cyclone collectors and gives

approximate sizes required for various appliTOP VIEW

cations. Selection should be made from this

graph between the dotted lines to provide a

good compromise of collecting efficiency to

horsepower load or pressure drop. These limits

are from 3 to 5 inches of pressure as measured

on the water gage and correspond to the recommended inlet velocities of 3,000 feet per

minute.

Space and height limitations will be factors

in choosing a multiple mount. A 4-foot-diameter

cyclone will be a minimum of 17 feet high (8-

foot body, 8-foot cone and at least 1 foot for

the clean-air exit pipe), whereas a 2-footdiameter cyclone will only be 9 feet high.

VELOCITY

RANGE

7000

-J I4000

3000

1 1 I

1 ^

,^

1

1

\y

\^ 1

1

2000 ^

^

1

^

1

1

5 6 7

FRONT VIEW

FIGURE 4-29.—Quadruple cyclone arrangement.

PRESSURE DROP,

INCHES OF WATER

FIGURE 4-30.—Small-diameter cyclone selection chart.

83
TABLE 4-16.—Cyclone sizing and arrangements recommended for average ginning conditions

Air

Single Double Triple Quadruple

Diameter, Approximate Diameter, Approximate Diameter, Approximate Diameter, Approximate

(ftVmin) D„ height Do height Do height Do height

(inches) (feet) (inches) (feet) (inches) (feet) (inches) (feet)

1,500 24 9 ... ...

2,000 28 10 20 8

2,500 31 11 22 8

3,000 34 12 24 9 20 8

4,000 40 14 28 10 23 8 20 8

5,000 44 16 31 11 26 10 22 8

6,000 48 17 34 12 28 10 24 9

7,000 37 13 30 11 26 10

8,000 40 14 32 12 28 10

9,000 42 15 34 12 29 11

10,000 44 16 36 13 31 11

11,000 46 16 38 14 32 12

12,000 48 17 40 14 34 12

14,000 42 15

16,000 45 16 40 14

18,000 48 17 42 15

20,000 44 16

22,000 46 16

24,000 48 17

For cyclones discharging into screw conveyors, care should be taken to provide sufficient

conveyor size and speed to prevent stoppages.

Conveyors mounted beneath trash-collecting

cyclones should be equipped with a hopper to

accommodate temporary overloads.

Since the splitter inlet transition on multiplecyclone arrangements is a potential source of

trouble, a single cyclone should be used on each

lint-cleaner waste fan whenever possible. If the

cyclones discharge into a screw conveyor, the

lint-cleaner waste cyclone should be located

near the outlet end of the conveyor to minimize

conveyor chokage.

INLINE FILTERS

Inline filters were developed specifically for

controlling fly lint and dust emissions from

condenser exhausts. Three designs of inline

filters are available (figs. 4-31 and 4-32).

In one of these, the stationary-screen design,

a fixed filtering screen is mounted in an arc

to match a rotating brush reel. In another, the

filtering screen covers a revolving drum, which

is cleaned by a rotating brush cylinder located

near the bottom of the drum. In the third design, called a round air filter, a flat circular

screen is cleaned by a brush attached to a

rotating arm.

LINT- AND DUST-LADEN

CONDENSER EXHAUST AIR

=0 FILTERED AIR

.^ COLLECTED WASTE

^ MATERIAL

1. FILTERING SCREEN

2. CLEANING BRUSH

FIGURE 4-31.—Schematic diagrams of three designs of

inline air filters. A, Stationary screen type. B, Revolving drum type. C, Round air filter.

All three designs operate on the same basic

filtering principle. Fly lint and small-leaf trash

are strained from the exhaust air by a finemesh filtering screen. Fly lint accumulates on

the screen, forming a filtering batt for the

separation of fine dust particles. Periodically,

the accumulated material must be removed

from the screen to prevent the buildup of

excessive back pressure.

Inline filters are most efficient when operated

on a collecting-cleaning cycle controlled by a

pressure-differential switch. The switch auto84
TABLE 4-17.—Specifications for bolting-grade

ivire cloth

PN-5244

FIGURE 4-32.—Three designs of inline air filter. Left to

right: round air filter, stationary screen type, and

revolving drum type.

matically starts the screen-cleaning action

when the pressure reaches a predetermined

level and then stops the cleaning action when

the pressure is relieved. This system allows an

efficient dust-filtering batt to form before the

screen is cleaned, which improves the dustcollecting ability of the inline filter. In those

instances in which inline filters are operated

without a pressure-differential switch, the

filter-cleaning mechanism is allowed to operate

continuously, simplifying the system but

significantly lowering dust-collection efficiency.

Switches should be adjusted to start the

cleaning action before the pressure reaches a

level that would critically affect exhaust fan

performance. The critical pressure varies from

installation to installation. However, experience

has shown that vaneaxial fans can usually

operate satisfactorily against pressures of 1 to

li/> inches of water over normal operating

pressure. Tubeaxial fan systems usually operate

satisfactorily when pressures do not exceed

% inch of water. Final adjustment of the

pressure-differential switch should be made

under actual operating conditions.

The collection efficiency of an inline filter

also depends upon the amounts of fly lint and

dust in the exhaust air. Tests in New Mexico

using machine-picked cotton showed an overall

collection efficiency of 87 percent for a stationary-screen inline filter on the exhaust of

a first-stage lint cleaner (Alberson and Baker

1964). Efficiencies of approximately 81 percent

Mesh of

screen

(wires/inch)

Wire Size of Open

diameter opening area

(inch) (inch) (pet)

Pressure drop

at 750-ft/min

face velocity

(inH^O)

40 by 40 0.0065 0.0185 54.8 0.04

70 by 70 .0037 .0106 54.9 .05

105 by 105 .0030 .0065 46.9 .10

were obtained in Texas when ginning machinestripped cotton (Baker and Parnell 1971). The

Texas tests also showed no significant differences in collection efficiency among the three

inline filter designs. Generally, an inline filter

can be expected to collect all of the fly lint and

up to about 70 percent of the fine dust.

Inline filters require fine-mesh filtering

screens with high open area percentages. Bolting-grade stainless steel or monel wire cloth

has proved to be effective. Dimensions of wire

cloth that have been successfully employed in

inline filters are given in table 4-17.

Inline filters should be sized according to the

volume of condenser exhaust air to be filtered.

Screen face velocities of approximately 750

feet per minute have been satisfactorily employed. This velocity results in initial added

pressure (screen resistance and shock losses)

of 0.3 inch of water or less. Lower face velocities can be used, but the size of the filter must

be increased. High face velocities create higher

pressures. Recommended screen sizes for

various air volumes are given in table 4-18.

Proper selection and adjustment of brushes

are required for effective cleaning of the filtering screen. Soft bristles, such as horsehair, are

not stiff enough; nylon bristles approximately

0.02 inch in diameter and 1 inch long have the

necessary stiffness for satisfactory cleaning of

filter screens. The brush should be adjusted so

that the tips of the bristles firmly contact all

of the screen surface area. Any part of the

screen that the brush fails to touch will not

be cleaned well and will tend to become clogged.

Brush reels for stationary-screen filters and

brush arms for round air filters should be

driven at speeds of about 12 revolutions per

minute. Brush cylinders on revolving drum

filters should operate at approximately 30

revolutions per minute.

Inline filters should be inspected daily

85
TABLE 4-18.—Screen-sizing table for inline filters

Condenser

capacity

( bales/h)

Exhaust

volume!

(ftVmin)

Exhaust fan

diameter

and type^

Gross

screen area

required^

Stationary

screen*

Revolving

drum

diameter "^

Round

filter

Radius Width diameter

(inches) (ft2) (inches) (inches) (inches) (inches)

Up to 2 Up to 3,000 V18 5.3 15 30 20 31

2 to 4 3,000 to 6,000 V18 to V21 10.6 21 42 30 44

4 to 6 6,000 to 9,000 V21 to T36 15.9 25 50 35 54

6 to 8 9,000 to 12,000 V24 to T42 21.2 29 58 41 62

8 to 10 12,000 to 15,000 V26 to T42 26.5 32 64 46 70

no to 15 15,000 to 20,000 T42 35.6 38 76 53 81

n5 to 20 20,000 to 25,000 T42 44.4 42 84 59 90

1 Exhaust volume measured without lint in the system.

2 Type of exhaust fan, vaneaxial or tubeaxial, indicated by letters V and T, respectively.

^ Gross screen area based on 750 ft/min face velocity, assuming a 25-percent loss in area for screen supports.

4 Based on a 120-degree screen arc.

•"' Length of revolving drum assumed to be equal to the diameter.

^' Press condensers only.

throughout the active ginning season. Accumulations of lint on the brushes should be removed,

and the waste exit should be kept clear of

obstructions. Any part of the filtering screen

which has become clogged should be cleaned

with an airhose. Each year, before the ginning

season starts, inline filters should be thoroughly

cleaned and inspected for (1) good brush contact, (2) screen condition, (3) clearance

through waste exit and mote lines, (4) correct

tension and alinement of chain drives, and

(5) accumulations of lint material in the

electric motors.

CONDENSER DRUM COVERING

Short fibers and dust exhausted from condenser fans are probably the emissions most

objectionable to gin employees and residents

of the immediate area. This lint fly settles on

electric lines, the gin yard, rooftops, and surroundings, causing not only a housekeeping

problem but a serious fire hazard.

Tests at the U.S. Cotton Ginning Research

Laboratory at Stoneville, Miss., have shown

that the lint fly problems can be eliminated,

for all practical purposes, by covering condenser drums with fine-mesh stainless-steel

screen wire or replacing covering with fine,

perforated metal (McCaskill and Moore 1966).

The screen wire can be either 100 by 100 mesh

with approximately 31 percent of open area or

70 by 70 mesh with approximately 54 percent

of open area. The fine, perforated metal should

have enough holes of 0.033-inch diameter to

give approximately 20 percent of open area

(table 4-19). The greater open area will result

in less pressure on the system. The lint fly is

eliminated, with only the very fine dust being

discharged with the exhaust air. The slight increase in air resistance is not a problem where

exhaust fans are used.

Figure 4-33 shows how this screen is applied

to a standard condenser. The screen is stretched

smooth over the condenser drum and soldered

around both ends and longitudinally across the

drum where seams are necessary. It will be

necessary to adjust the doffing rollers to insure

clearance to the drum.

CAUTION: Condenser drums that are

blanked off with no more than one-fourth of the

drum area exposed to the inlet air and lint

should not be covered with screen. Ample exposed drum area is necessary to compensate

Fine Screen over Standard Drum

Fine Perforated Metal

FIGURE 4-33.—Condenser drum covering.

86
TABLE 4-19.—Dust and lint fly in emissions from a unit lint cleaner

condenser exhaust with various types of coverings

Holes

Type of drum covering per

and hole diameter square

inch

Perforated metal, 0.109-inch diameter

(standard) 47

Perforated metal, 0.033-inch diameter. 234

100-by 100-mesh screen (31.4 percent

open area) over standard drum

(45 percent open area) {^)

70-by 70-mesh screen (54.9 percent

open area) over standard drum

(45 percent open area) i^)

1 0.0056 inch between mesh.

2 0.0106 inch between mesh.

Open

area

(percent)

Lint fly Static

and dust pressure

concentration loss

(g/l,000ft3) (inHgO)

45

20

14

25

50.8

32.0

21.6

0.52

.70

.75

for the reduction in open area when fine screen

is applied.

SKIMMERS

Skimmers are occasionally used instead of

small-diameter cyclones for those fan exhausts

that do not discharge large trash. Exhausts

from unloader fans, overflow-suction fans, and

separator-pull fans contain small-leaf trash,

dust particles, and fly lint. Some of this small

material can be collected by skimmers, but

large trash such as burs and sticks clog the

skimmer's narrow skimming slot.

Exhaust air enters the skimmer and follows

the curved side walls along a circular arc 90°

to 180° (fig. 4-34). The circular motion creates

centrifugal forces that act on the entrained

trash particles, pushing them toward the outside wall, where an adjustable vane and slot

skims the particles and some of the air from

the main airstream. The skimmed air must

then be discharged into another trash-collection

device, such as a cyclone collector, for final

separation of the trash. The remainder of the

main airstream is exhausted to the atmosphere.

The collection efficiency and pressure characteristics of a skimmer depend upon its radius

of curvature, the air velocity, and the size of

the skimming-slot opening. The size and weight

of the particulate matter entrained in the air

also affect collection efficiency. Higher collection efficiencies and pressure are associated

with short radius of curvature, high velocity,

and wide skimming slot. Thus, the design of

a skimmer requires a compromise between colInlet

Main Air

Exit

Skinming

Slot

FIGURE 4-34.—Schematic diagram of a skimmer.

lection efficiency, operating pressure, and the

volume of skimmed air that requires further

cleaning.

BUR HOPPERS

It is usually necessary for cotton gins to

store gin trash temporarily prior to final disposal. Elevated bur hoppers provide a convenient means of accumulating truckloads of

gin trash, and they also expedite the loading

operation (fig. 4-35). Loading the trucks is

accomplished by simply opening the bottom

of the bur hopper and allowing the accumulated

trash to fall into the truck.

Bur hoppers are available in lengths of 20,

87
PN-5245

FIGURE 4-35.—Typical bur hopper and spreader truck

used extensively in stripper-harvesting areas.

30, and 40 feet. The hopper size required depends upon the type of cotton being ginned,

the ginning rate, and the number of trucks

being used to haul trash. Low-capacity gins

processing less than eight bales of stripped

cotton per hour or gins processing picked cotton

usually find 20-foot hoppers satisfactory.

Higher capacity gins, especially those ginning

stripped cotton, require the 30- and 40-foot

hoppers.

Trash can be blown directly into a bur hopper

by one or more air lines or dropped into the

hopper by cyclone collectors. The use of cyclone

collectors is the preferred method. All of a

gin's cyclone collectors may be mounted on

top of the hopper (fig. 4-36). However, this

practice has the disadvantages of inaccessibility

to the collectors and a high risk of wind damage. In recent years, it has become common for

gins to group most of their cyclones into a

bank located close to the ground and to concentrate the separations from each collector

into a single air line discharging into a single

set of collectors on top of the hopper (fig.

4-37).

LIVESTOCK FEED

In a few areas of the Cotton Belt, gin trash

has become important as a livestock feed. On

the High Plains of Texas, where concentrated

cattle-feeding operations have been developed.

PN-6246

FIGURE 4-36.—Bur hopper with several pairs of cyclone

collectors mounted on top.

PN-5247

FIGURE 4-37.—A well-designed trash collection system

with the main cyclone bank located near ground

and one pair of cyclones loading the bur hopper.

the use of gin trash as a feed roughage has

become commonplace. Gin trash is usually

ground and mixed with the other rations at

feed lots before feeding. However, some stockmen feed unground gin trash to their cattle

as a supplemental roughage, usually allowing

them to feed at will from piles of trash

deposited on the ground.

Several cotton gins have installed elaborate

grinding and pelleting equipment for gin trash

(fig. 4-38). These systems produce pellets

about one-fourth inch in diameter that can be

88
PN-6248

FIGURE 4-38.—Six bur pelleting machines at Acuff

Co-operative Gin, Acuff, Tex.

FROM CONDENSERS

l^n-— FROM TRASH FANS

TO CYCLONE

FIGURE 4-39.—Schematic of experimental filter

enclosure.

easily handled, stored, and transported. Gin

trash pellets, because of their high bulk density,

can be economically shipped long distances;

also, pellets are easier to handle and to mix with

other feedstuffs than untreated gin trash. Storage is also simplified since pellets do not constitute as much of a fire hazard as untreated

gin trash. Molasses or other materials can be

added to gin trash during pelleting to increase

its nutritional value and palatability.

UNIFILTER COLLECTION SYSTEM

A totally new system for collecting all waste

from a cotton gin has been developed at the

PN-B249

FIGURE 4-40.—Vacuum nozzles doffing filter drum

covered with nonwoven polyester media.

TABLE 4-20.—Overall filter efficiency of the

unifilter collection system for three ginning

rates

Ginning rate

(bales/h)

Trash input

(Ib/h)

Overall efficiency

(pet)

4

6

571

851

1,097

99.23

99.36

99.55

U.S. Cotton Ginning Research Laboratory

(McCaskill and Wesley 1974). The unifilter

trash-collection system is composed of a settling

chamber equipped with an impinging baffle

and a revolving drum covered with a filter

medium. Figure 4-39 shows the arrangement

of the components in the system. Light material and dust collect on the filter medium and

are removed by vacuum nozzles (fig. 4-40).

Cleaned air is discharged from both ends of

the filter drum. After feasibility studies on

small models indicated that the principle was

sound, a model that would handle 25,000 cubic

feet of air per minute was built and evaluated

for overall collection efficiency (table 4-20).

A full-size trash collection system has been

designed, fabricated, and installed for operational studies at a commercial gin whose ca89
PN-62B0

FIGURE 4-41.—Commercial-size experimental trash

collection system.

pacity is 15 to 20 bales per hour. The enclosure

is 13 feet wide, 24 feet long, and 16 feet high,

with a trash hopper underneath (fig. 4-41).

A 12-inch-diameter screw conveyor is located

in the bottom of the hopper to carry the heavy

trash to a vacuum dropper, which removes the

trash from the enclosure. Two filter drums,

each 8 feet in diameter and 13 feet long, are

located near the top of the enclosure. The filtered air is discharged from both ends of the

drums to the atmosphere. The drums are covered with a nonwoven polyester medium which

has a higher efficiency than polyurethane foam.

The line carrying low-pressure condenser air

is shown entering the enclosure above the filter

drums, whereas the line for trash-laden, highpressure air enters below the drums and is

deflected down into the hopper to protect the

medium. The low-pressure condenser air can

be introduced into the enclosure below the

filter drums, if desired, without affecting

system efficiency.

All of the air discharged from the gin is

piped into the enclosure for cleaning. A total

of 111,000 cubic feet per minute of contaminated air is cleaned through 500 square feet of

filter. This volume of airflow results in a face

velocity of 222 feet per minute on the filter.

The light material and dust collect on the

filter medium, which is continuously cleaned

by 10 nozzles, each 24 inches wide. A No. 50

fan furnishes 700 cubic feet of air per nozzle

per minute. This fan also handles the trash

from the hopper.

The system was in operation for the entire

1973 season, during the ginning of over 7,000

HEATED AIR TO

GIN DRIERS

GIN TRASH

- AMBIENT AIR

-\ /—UPPER CHAMBER

/—LOWER CHAMBER

ASH DISCHARGE

F'lGURE 4-42.—Schematic of incinerator disposal system.

bales of machine-picked cotton. It was found

necessary to clean out the nozzles and remove

the trash buildup on the nozzle supports every

200 to 300 bales, a job accomplished by 2 men

in about 10 minutes on each occasion. Lint

catching on parts of the nozzles can cause a

problem, especially if lint-cleaner waste is collected with this system. These portions of the

nozzles which cause problems should be removed if possible and the nozzles sanded

smooth, especially around the ends where tags

normally start to form.

The flexible plastic hose between the nozzle

and the suction manifold should be a materialshandling type with a rubber liner.

Several rib fires occurred during the ginning season, and at least four major fires went

through the filter to the trash pile. These fires

caused no damage to the filter enclosure and

only minor damage to the filter medium—not

enough to require replacement.

The proper sizing of a unifilter system for

a gin plant is dependent on the volume of air

to be filtered and the face velocity at the

filter medium. The efficiency goes up as the

face velocity goes dov^^Tx A face velocity of 150

to 250 feet per minute is satisfactory.

Table 4-21 gives the capacity at various face

velocities for several drum sizes. The enclosure

should be designed to fit the size and number

of drums chosen for a particular installation.

RESEARCH ON INCINERATOR

Of the many disposal methods being tried,

incineration is the simplest for the ginner;

however, no incinerator installed at gins before

90
TABLE 4-21.—Filter selection for unifilter collection systems, based on air

volume and face velocity at filter medium

Drum Filter

area

Number

of

Air volume (ftVmin ) at face velocity of—

diameter 100 150 200 250

(ft) (ft^) nozzles ft/min ft/min ft/min ft/min

4 50.4 2 5,040 7,560 10,080 12,600

4 75.6 3 7,560 11,340 15,120 18,900

5 62.8 2 6,280 9,420 12,560 15,700

5 94.2 3 9,420 14,130 18,840 23,550

5 125.6 4 12,560 18,840 25,120 31,400

6 75.2 2 7,520 11,280 15,040 18,800

6 112.8 3 11,280 16,920 22,560 28,200

6 150.4 4 15,040 22,560 30,080 37,600

7 88.0 2 8,800 13,200 17,600 22,000

7 132.0 3 13,200 19,800 26,400 33,000

7 176.0 4 17,600 26,400 35,200 44,000

7 220.0 5 22,000 33,000 44,000 55,000

8 150 3 15,000 22,500 30,000 37,500

8 200 4 20,000 30,000 40,000 50,000

8 250 5 25,000 37,500 50,000 62,500

8 300 6 30,000 45,000 60,000 75,000

9 169.8 3 16,980 25,470 33,960 42,450

9 226.4 4 22,640 33,960 45,280 56,600

9 283.0 5 28,300 42,450 56,600 70,750

9 339.6 6 33,960 50,940 67,920 84,900

10 188.4 3 18,840 28,260 37,680 47,100

10 251.2 4 25,120 37,680 50,240 62,800

10 314.0 5 31,400 47,100 62,800 78,500

10 376.8 6 37,680 56,520 75,360 94,200

1975 meets the strict emission standards now in

force. Incinerators approved for all types of

standard waste are available on the market, but

none have been approved specifically for gin

waste.

The Cotton Ginning Research Laboratory at

Stoneville, Miss., has installed a small, multichamber incinerator to study its ability to dispose of gin waste (McCaskill and Wesley 1974).

This system is composed of an automatic loader,

two burning chambers, an automatic ash removal system, and a heat exchanger in the

stack (fig. 4-42).

The incinerator operates on the controlledair principle. Waste is heated in the lower

chamber by controlling the introduction of air

which, in turn, controls the temperature. This

system results in very low air velocities so that

ash particles are not entrained and carried to

the upper chamber. Only smoke, unburned

gases, and very small particles pass into the

upper chamber. In the upper chamber the

smoke is reheated and additional air is introduced so that the gases and smoke particles

are oxidized rapidly. The high-temperature

stack gases leave the upper chamber and enter

the heat exchanger, where they are cooled by

air passing over the wall of the exchanger.

As the waste moves across the lower chamber,

it is reduced to ash and discharged from the

incinerator by the ash removal cylinder.

A pound of gin trash contains approximately

7,000 Btu of heat, depending on composition

and moisture content. Based on an average of

203 pounds of trash per bale from machinepicked cotton and 740 pounds per bale from

machine-stripped, the total potential heat value

per bale would be 1,421,000 Btu for machinepicked cotton and 5,880,000 Btu for machinestripped cotton.

If the heat exchanger is capable of operating

at 40 percent efficiency, a 10-bale-per-hour gin

plant could possibly reclaim 5,684,000 Btu

per hour from machine-picked cotton and

23,520,000 Btu per hour from machine-stripped

cotton. This amount of heat should be adequate

for drying cotton under almost all conditions

when ginning machine-picked cotton and more

than adequate when ginning machine-stripped

cotton. Reclaiming this heat would help offset

91
the initial investment in an incinerator equipped with a heat exchanger.

REFERENCES

Alberson, D. M., and Baker, R. V. 1964. An inline air

filter for collecting cotton gin condenser air pollutants. U.S. Dep. Agrie, Agrie. Res. Serv. [Rep.]

ARS 42-103, 16 pp.

Baker, R. V., and Parnell, C. B. 1971. Three types of

condenser exhaust filters of fly lint and dust control

Pink BoUworm Control in

Gin Operations

By I. W. KIRK

Some cotton-production areas, primarily in

the Southwestern United States, are infested

with pink bollworms, Pectinophora gossypiella

(Saunders). The pink bollworm is an insect

that can cause severe damage to cotton. The

U.S. Department of Agriculture, cooperating

with State departments of agriculture, requires

that certain regulations be observed to prevent

the buildup and spread of this destructive cotton pest. These regulations pertain to the treatment and movement of cotton, cottonseed, and

their byproducts within and from regulated

areas. Producers, ginners, and seed processors

are affected by these regulations. Those regulations pertaining to gin operations are discussed here.

PINK BOLLWORM QUARANTINE AND

REGULATIONS

Quarantines and regulations are enforced by

States and the Animal and Plant Health Inspection Service, Plant Protection and Quarantine Program (USDA). Assistance with

specific problems or information on current

regulations may be obtained by calling local

APHIS representatives listed under United

States Government, Department of Agriculture,

in the telephone book.

The Code of Federal Regulations, Title 7,

Chapter III, Part 301, Section 301.52-2a, as

revised February 20, 1976, designated certain

States or parts of certain States as pink bollworm regulated areas. The regulated areas are

divided into generally infested areas and

suppressive areas as follows:

Arizona

(1) Generally infested area: Entire State.

(2) Suppressive area: None.

at cotton gins. U.S. Dep. Agrie, Agrie. Res. Serv.

[Rep.] ARS 42-192, 13 pp.

McCaskill, O. L., and Moore, V. P. 1966. Elimination of

lint fly. The Cotton Gin and Oil MiU Press 67(27) :

5-7.

, and Wesley, R. A. 1974. The latest in pollution

control. The Cotton Ginners' Journal and Yearbook

42(1): 34-38.

Wesley, R. A., Mayfield, W. D., and McCaskill, 0. L.

1972. An evaluation of the cyclone collector for cotton

gins. U.S. Dep. Agrie. Tech. Bull. 1439, 13 pp.

Arkansas

( 1 ) Generally infested area : None.

(2) Suppressive area :

Clay County. The entire county.

Conway County. The entire county.

Craighead County. The entire county.

Crittenden County. That portion of the county

lying north of U.S. Highway 70, west of Interstate 55, and south of State Highway 42.

Franklin County. The entire county.

Green County. The entire county.

Independence County. The entire county.

Jackson County. The entire county.

Jefferson County. The entire county.

Johnson County. The entire county.

Lafayette County. The entire county.

Lawrence County. The entire county.

Lincoln County. That portion of the county lying

north of U.S. Highway 65.

Little River County. The entire county.

Logan County. The entire county.

Lonoke County. The entire county.

Miller County. The entire county.

Mississippi County. That portion of the county

lying north of State Highway 118, east of State

Highway 77, south of State Highway 158, and

west of the Mississippi River.

Poinsett County. That portion of the county lying

west of the St. Francis River.

Pope County. The entire county.

Pulaski County. The entire county.

Randolph County. The entire county.

Washington County. The entire county.

Woodruff County. The entire county.

Yell County. The entire county.

California

(1) Generally infested area:

Imperial County. The entire county.

Inyo County. That portion of the county lying

east of the east boundary of Range 4 East,

SBBM.

Los Angeles County. That portion of the county

lying east of the east boundary of Range 15

West and north of the north boundary of Township 4, North, SBBM.

Riverside County. The entire county.

San Bernardino County. That portion of the

county lying east of the east boundary of Range

4 East, SBBM.

San Diego County. The entire county.

92
(2)

(1)

(2)

(1)

(2)

(1)

(2)

(1)

(2)

(1)

(2)

(1)

(2)

Suppressive area:

Fresno County. The entire county.

Kern County. The entire county.

Kings County. The entire county.

Madera County. The entire county.

Merced County. The entire county.

Tulare County. The entire county.

Florida

Generally infested area : None.

Suppressive area:

Broward County. The entire county.

Charlotte County. The entire county.

Collier County. The entire county.

Dade County. The entire county.

DeSoto County. The entire county.

Glades County. The entire county.

Hardee County. The entire county.

Hendry County. The entire county.

Highlands County. The entire county.

Hillsborough County. The entire county.

Lee County. The entire county.

Manatee County. The entire county.

Martin County. The entire county.

Monroe County. The entire county.

Okeechobee County. The entire county.

Palm Beach County. The entire county.

Pinellas County. The entire county.

Sarasota County. The entire county.

St. Lucie County. The entire county.

Louisiana

Generally infested area : None.

Suppressive area :

Bienville Parish. The entire parish.

Bossier Parish. The entire parish.

Caddo Parish. The entire parish.

Catahoula Parish. The entire parish.

DeSoto Parish. The entire parish.

Grant Parish. The entire parish.

Natchitoches Parish. The entire parish.

Rapides Parish. The entire parish.

Red River Parish. The entire parish.

Webster Parish. The entire parish.

Missouri

Generally infested area : None.

Suppressive area :

Butler County. The entire county.

Dunklin County. The entire county.

Mississippi County. The entire county.

New Madrid County. The entire county.

Pemiscot County. The entire county.

Ripley County. The entire county.

Scott County. The entire county.

Stoddard County. The entire county.

Nevada

Generally infested area :

Clark County. The entire county.

Nye County. The entire county.

Suppressive area : None.

New Mexico

Generally infested area : Entire State.

Suppressive area: None.

Oklahoma

Generally infested area : Entire State.

Suppressive area: None.

Texas

( 1 ) Generally infested area : Entire S'tate.

(2) Suppressive area : None.

The following articles may not be moved

interstate from any regulated area except with

an appropriate certificate or permit:

1. Cotton and wild cotton, including all parts

of such plants.

2. Seed cotton.

3. Cottonseed.

4. Cottonseed hulls.

5. Cotton lint.

Baled cotton lint is exempt if compressed

to a minimum of 22 pounds per cubic foot.

Baled cotton lint moving from the generally infested area into the suppressive area

is exempt if the lint is from seed cotton

produced in the suppressive area and

moved to the generally infested area for

ginning, provided the identity of the baled

cotton lint is maintained.

Samples of cotton lint of the usual trade

size are exempt. The samples may be

assembled in a single package for shipment.

6. Cotton linters.

Linters are exempt if compressed to a

minimum of 22 pounds per cubic foot.

Samples of cotton linters of the usual

trade size are exempt. Samples may be

assembled in a single package for shipment.

7. Cotton waste produced at cotton gins, cottonseed oil mills, and cotton textile mills.

Lint cleaner waste is exempt if compressed

to a minimum of 22 pounds per cubic foot.

8. Cotton gin trash.

9. Used bagging and other used wrappers for

cotton.

10. Used cotton harvesting equipment and

used cotton ginning and cotton oil mill

equipment.

11. Okra and kenaf, including all parts of such

plants except canned or frozen okra.

Edible okra is exempt if produced during

the period December 1 to May 15 inclusive, except that okra consigned to California is exempt only if produced during

the period of January 1 to March 15

inclusive.

12. Any other products, articles, or means of

conveyance of any character whatsoever,

not covered by the above, when it is determined by an inspector that they present

a hazard of spread of the pink bollworm

93
and the person in possession thereof has

been so notified.

However, treatments and attachment of certificates or permits are not required to move

the above materials interstate from a generally

infested area to a contiguous generally infested

area or from a suppressive area to a contiguous

generally infested area.

Cottonseed,—In general, cottonseed can move

freely to oil mills within the generally infested

or suppressive regulated areas without treatment.

Cottonseed may be eligible for movement outside the regulated area provided it is (1) heated

to 150° F for at least 30 seconds or 145° F for

at least 45 seconds or (2) fumigated with

methyl bromide, hydrocyanic acid, or aluminum

phosphide. Most cotton planting-seed acid delinting plants qualify seed for movement under

1 above.

Cottonseed may also be eligible for movement, for processing on arrival, by APHIS

permit during host-free periods from a generally infested area to a suppressive area or from

a suppressive area to a nonregulated area.

Gin trash,—The ginner is affected by quarantine regulations in disposing of gin trash.

Several approved methods of treatment may be

used, but the single-fan treatment method is

used most extensively.

Research has shown that if gin trash is passed

through the wheel of a conventional trash fan

operating according to pink bollworm quarantine regulations, the action of the fan will kill

the pink bollworms in the trash. These specified

conditions are:

1. No fan shall be used with a wheel diameter

of less than 19 inches.

2. The housing or scroll shall be constructed

of plate steel or cast iron.

3. Patching of housing shall be by welding

or plate or cast insertions. No patching

shall be done with belting, sacks, rubber,

or any other shock absorbing substance,

but the fan housing or scroll and piping

elbows may be lined with rubber if desired.

4. No gin trash wheel shall be used in an

oversized casing, but oversized or standard

wheels may be used in standard casings

only.

5. The wheel must be laterally centered to

have equal clearance front and back.

TABLE 4-22.—Federal pink bollworm quarantine requirements regarding wheel diameter, inlet size, and S'peed of operation of

single fans for treating gin trash

Fan wheel Maximum Minimum Maximum

diameter inlet size speed safe speed

(inches) (inches) (r/min) (r/min)

19 ) 1 2,760 3,020

i9y2 10 to 10 y2 2,690 2,940

20 '

' 2,620 2,860

20% 2,560 2,790

21 2,490 2,730

21 Va 2,430 2,660

22 10% to 11 2,380 2,610

221/2 2,330 2,550

23 2,280 2,490

231/2 2,230 2,440

24 2,180 2,390

24% 2,140 2,340

25 iiy2toi2 i 2,090 2,290

25 y2 2,100 2,250

26 2,060 2,200

26 Vz 2,020 2,160

27 1,980 2,120

27y2 f 1,940 2,080

28 1,910 2,050

28y2 1,880 2,010

29 1,840 1,980

29y2

30 12 to i2y2 <

1,810

1,790

1,940

1,910

3oy2 1,750 1,880

31 1,725 1,850

3iy2 1,700 1,825

32 1,700 1,790

32% 1,700 1,760

8.

The fan wheel may be either a standard

straight, forward, reverse, or curved tip

having not less than six blades.

Trash must enter at a 90° angle to the

fan wheel. This may be accomplished by

the use of either a straight inlet pipe or a

90° elbow (fig. 4-43) ; however, previously

approved banjo-type elbows and adapters

are acceptable.

Fan wheel speeds shall comply with the

speed in table 4-22. Fans of larger diameter than shown in the table shall have

a minimum speed of 1,700 revolutions per

minute.

In the event that the inlet pipe is smaller

in diameter than the fan housing inlet, the

same pipe size should be maintained to the

fan housing and protrude inside as shown

94
10.

^ MINIMUM DIAMETER:

GIN TRASH FANS - 19 INCHES

LINT CLEANER WASTE AND

MOTE FANS - 18 INCHES

FIGURE 4-43.—Approved fan inlet connections.

in figure 4-43. Tapered cone inlet adapter

for pipe connections to fan should not be

used, unless the inlet pipe is larger in

diameter than the fan housing inlet. The

inlet pipe should extend at least fiveeighths inch past the fan housing.

Inlet pipe to the fan shall not exceed the

diameter of the pipe bringing material to

the fan.

Lint'Cleaner ivaste and motes,—Lint-cleaner

waste and motes are not considered the same as

gin trash. However, quarantine requirements

for handling these materials are essentially the

same as for handling gin trash. The single-fan

method of treatment as specified above for gin

trash is appropriate for handling lint-cleaner

waste and motes with the following exceptions:

1. Minimum fan wheel diameter may be 18

inches. (Minimum speed for 18-inch-diameter lint-cleaner waste or mote fan is 2,550

revolutions per minute.)

2. Minimum fan speeds may be reduced 12

percent from those shown in table 4-22.

SAFETY WARNING: Fans must not be

operated above their design maximum safe

speed. Fan-manufacturing companies can supply this information. As a general rule, tip

speed of gin trash fans should not exceed 15,000

feet per minute for safe operation.

Gin machinery and equipment,—Mechanical

cotton-processing machinery that has been used

in regulated areas must be fumigated with

methyl bromide according to APHIS regulations before it may be transported to nonregulated areas. However, storage of unused

gin equipment for 2 years prior to shipment

will also be approved as adequate treatment.

EVALUATING GIN SYSTEMS FOR

PINK BOLLWORM KILL POTENTIAL

A high percentage of pink bollworms are

killed during the cotton-ginning process. Research has shown increasing kill percentage

with increasing complexity of the gin setup.

This research has also shown that the capability

of a system for killing pink bollworms during

processing could be related to the number of

Equipment item

Equivalent

cylinders (each)

Number of

items

Total

cylinders

Drier' 2

Cleaner Actual

Bur extractor or stick machine • . 3

Separator 4

Extractor feeder • • • • 6

Gin2 10

Seed blow system .. 3

Total

Percent kill

' Based on 24-shelf drier without heat.

^ If gin is operating below 600 r/min it is not rated because of low kill.

FIGURE 4-44.—Sample form for rating gins for pink bollworm kill.

95
100

98

96

94

o

oc 92

90

88 -

Mr X j- j- JL

20 30 40

EQUIVALENT NUMBER OF CYLINDERS

50

FIGURE 4-45.—Percentage of expected pink bollworm kill in a ginning system for

various numbers of equivalent cleaning cylinders in the system.

cleaning cylinders in the overhead cleaning

system plus conversion factors equivalent to

cylinders of cleaning for the remainder of the

various pieces of equipment in the system.

Figure 4-44 shows the cylinder conversion

equivalents and a tabulation form for rating

the gin system. The expected percentage of

pink bollworm kill for a rated gin system is

found in figure 4-45 from the equivalent total

cylinders for the gin system.

REFERENCES

Graham, H. M., Robertson, O. T., and Stedronsky, V. L.

1967. A method of evaluating cotton gins for pink

bollworm kill. U.S. Dep. Agrie, Agrie. Res. Serv.

[Rep.] ARS 33-121, 5 pp.

Robertson, 0. T., Martin, D. F., Alberson, D. M.,

Stedronsky, V. L., and McEachern, D. M. 1963. Pink

bollworm kill with improved gin equipment. U.S.

Dep. Agrie. Prod. Res. Rep. 73, 8 pp.

, Stedronsky, V. L., and Currie, D. H. 1959.

Kill of pink bollworm in the cotton gin and the oil

mill. U.S. Dep. Agrie. Prod. Res. Rep. 26, 22 pp.

96
SECTION 5.-POWER: MOTORS AND ENGINES

By W. E. GARNER

As elsewhere in industry, energy shortages Table 5-1 lists the brake horsepower and

and high fuel prices have focused attention on other characteristics of several engines deways to reduce the cost of power in cotton gins. signed for continuous cotton-gin service.

The advantages and disadvantages of the most Figure .5-1 shows a diesel engine installed in

common sources of power are presented here, a cotton gin as the main source of power,

to assist ginners in evaluating these factors, The amount of electrical energy required

so as to select the most economical and efficient varies considerably, depending on how constant

sources of power for a given installation. and intermittent loads are handled and on how

The principal characteristics required of much fans and other accessories are used. In

cotton-gin power units are constant speed, electrically operated gins, it is highly advisable

ample capacity to handle overloads, durability, to have separate motors to carry the intermitand economy in operation and maintenance. tent work loads of pumps, presses, and seed

The most common sources of power are electric loading rather than have the main motor carry

motors and diesel, natural gas, and liquefied these loads. (In large gins, this tends to result

petroleum (bottled) gas engines. Each has in numerous motors for individual drives,

significant advantages and disadvantages. Electric power companies usually offer conA 1974 survey of gin equipment in the United suiting and testing services to their patrons,

States by the USDA Agricultural Marketing to assist them achieve the most economical use

Service showed that the percentages of each of electricity.)

source of power for the main engine or motor Manufacturers of cotton-ginning machinery

were as follows: publish data sheets giving the recommended

Percent horsepower for their machines, such as gin

Electricity 83.6 stands, separators, cleaners, and condensers,

Diesel fuel 6.8 operating at varying capacities. These data

Natural gas "•"

Bottled gas 2.9

Other 0.1

Several factors should be considered in selecting a power unit for a given installation. ^^^^_^ ^„^^. ,r^^^

Among these are amount of power required, ^^^PK fF^^^É"^ XT "^^^^^

initial cost of equipment, cost of fuel or electric ^BP'i^^'^'^ ¿^ÍKIET'

energy, cost of lubrication, kind of labor needed,

expense of maintenance, probable service life, ^t^;^ rfy-ifxy

and decrease in power capacity resulting from yT'^w -W* - v^^-^^lÄfili <

use. ^ V •

Diesel, natural gas, and LPG engines have

much to recommend them for the seasonal ^m¡ ^

service of cotton ginning. In selecting such ^^. -^mJi^^I —*-J

engines, the purchaser should allow for a liberal «» ^■■P^ ï I (

margin in power over that which is normally

required, to accommodate peak loads and future

expansion. Most manufacturers have a continuous rating for their engines. This rating PN-B26I

should be applicable for continuous-duty cotton- FIGURE 5-1.—A diesel engine used as the main source

gin service without further derating. of power in a cotton gin.

97
'S ."tí

.te^

î3

buO

c«o

pq

i3 ^«^ O

î3

^

.S

w

co

c

¿û

S

-e

^

2

®

?1 ^^ s ^

tí riíá X

Co s ft

r£3

SUDü

o

(M (N <Moooo

Ifî lO iO «O <X> C» CO

TH TH iH CO <X> (M ÇD

OOOOO

lO C5 00 CO CO O lO (M (X> CO

COCO(MCOCO(N(MCOCO

OOOOOOO

ooooooo

low looo Ißo

cg (N t> cví

ooooo

ooooo

o lO lOoo

o" 00"^ (M' C^"

oooooooooooo

OOOOOOOOOiOOO

TH iH rH T-TTH r-rr-Tr-Tr-rT-Tr-rTH"

(MlOt-THC^IOSrHt^OCOÇOO

o:iC<jt-<X)TíiiococoTHooiot-

(WlO00(NCOlO00(NCO^Oí^C0'«:í<

Oït-t>00000100lOO

CX)(X)Tí<C00:»lOlCL0CNOt^O

(MCOCOOíOíTH^CO^COOíC^I'^CO

TH TH TH" r-T C<r C<r CO

OOOOOOOOOOOO

oooooooooooo

OOC»0000C>0C)0C»C>0C»00 00

COCOLOOOt-OOt-TjíOíMOO

05C<lTl<t-Or}<t>Tj<OÇ0(Mai

THTHTH(N(M<MeOTí<TíiiocO

TÍ4COin)LDOCOlOOLOOOO

Cg(X»05«i000<MÇ0t>^(NO'^

THTHTHC<I(MCOCO'^lO<X)t>a5

OOOOOOOOOOOO

oooooooooooo

CO 00 C^^ (N C^" (>í (>Í oí (N cg (N c^r ®®®®®®®®®®®®

THOT}<OOOI>-'«^LO(Mt-THlO

THlflt>lOÇOO:>CO'^(NOiC5C5

THTHTHCq(M(NCO"«^iOLOçO00

OiCQlßlOOOOOOOOO

Tj<OCOCOCOOlOOOOOO

TH(M(McOC0'^Tj<COt>00o:i(M

C^COOOOOOiOtiOOOOOO

ÇÔoÔTjÎTj3TiîrJ<o6oÔOO*oÔt>l>

THTHIHTHTHTHíMC^ICOCO

OOTfIßLOlOLOOOOOOO

t-OU^ilOmiOLOlOiHrHOO

COlOOOOOOOOOrH^THl>l>CO^CO

TH r-T TH TH C<r csT

COCOÎOÇOÇOCDÇOCO^COÇOCO

i>t>ooooa5CïOoa5C5

Tj<Ti<ir5lOlOlO;OCOLO^ÇOçO

CO CO ÇO CO CD ÎO

CO 00

CÖc s::c

.s <M (N <M (M ^ TH ^ rH r-l

iH (M <N f-H LA lO'

CL, Cil CL( »A^ '^ »^

00^ lO^ '. I ^

OOO

oo- 00

i>o »Ä 00 -. ,

<<^

CO LO 00^^^^

>>^ iz;^^W

<<< H H H W > >

w

o

COo

00C

H5 C3

"73 'O

CÖ p^

.aC PH CÖ

CÖ^

o

CO

^C

^O

8^

O) r-H

no .tí

*fg

s^

g.s o

-£o

Tí

•73

.0

03

.tí W2 W fí fH

bes tí

pj 13 CO

+^I

oí *E1)p

.2C

«I pj O '^.-

"-• ItZ^

O)^^

-^m

c "gm

^§è

'H3 .S^

-aoX tï ci cö

^^^

rH Cl CÖ

C/2

CÖ

CÖdo

COS

T3^

t^Ci^CO

^ ci ^ ¿?

•^2

§§

'S «HO

<D CO Ö bX)

•5b.S

Cg

n3

CiO

^ í3

ft.S CO -íJ

ciC

^¿

Si ^3 O)

-P "73

Cio

«S

<D .1-1

-P r-J CO

r-H P-H OJ

O)

CO <JÍ TJ C .t:

CO

TJ

Í3

o

CO

ci

-^-00 o o» 00

Ci r^

r.so

;:: í3O

-)o "3

' r^ CO 'T3

bx) . -^

Ip O)

ci Euo

CO

CO^

a> Oí

•b¿g

O)

*><r§ t ^ ,-H

4^^ 'SCi

O

'Sbo

98
Sheets usually show both the recommended size

for an individual electric motor and the horsepower to be used for calculating total horsepower requirements for a central engine-driven

plant. The horsepower for purposes of calculation in a central engine-driven plant is less

than the recommended horsepower for individual electric motors. This is due to the fact

that normally an individual machine will require much less horsepower than is required

to overcome periodic surges of flow through

the equipment. In a central engine-driven plant,

the surges will average out at any one time so

that the overall load on the central engine

will never need to be as great as the sum of

the horsepowers of the individual electric

motors.

Electric motors for powering cotton gins

must be able to operate in air heavily laden

with dirt and lint, which is common to cotton

gins. Also, the ambient temperatures, particularly in the upper areas of a cotton gin, often

become very high. In addition, it is impossible

to obtain uniform power requirements for the

various machines in the gin plant, even though

bulk feed-control units have done much to level

out extreme surges in power requirements.

Uniformity in these conditions is difficult for

any one type of electric motor to attain.

Totally enclosed motors are protected from

dust and lint, but even fan-cooled enclosed

motors do not have the overload capacity of

open motors, which can dissipate heat more

easily. The totally enclosed motor may give

more trouble because of overheating than the

open motor will give because of contamination

from dust and lint. A compromise may be a

motor built in a large frame that has large

openings to prevent clogging by lint and dust.

The large frame enables this motor to dissipate

heat more readily. Thus, the motor can operate

under overloads of up to 25 percent for short

periods of time to overcome the incalculable

surges that sometimes develop in gin machinery. The cost of this large-frame, open motor

is between the costs of a standard drip-proof

motor and the totally enclosed fan-cooled motor,

which is the most expensive. Despite apparent

shortcomings, many standard drip-proof motors

are giving satisfactory service.

REFERENCE

U.S. Agricultural Marketing Service. 1974. Cotton gin

equipment, 3 pp.

99

SECTION 6.-GINNING RECOMMENDATIONS

Gins To Handle Specific Types

of Cotton

By W. E. GARNER and R. V. BAKER

Numerous tests by the Agricultural Research

Service's cotton ginning research laboratories

and cooperating agencies of USDA have formed

the basis for recommendations on the sequence

and amount of gin machinery to be used with

cotton harvested by various methods, to achieve

satisfactory bale value for the producer on one

hand and to preserve the inherent quality of

the cotton on the other.

As a result of these findings, and considering

premiums and discounts of the marketing system, recommendations for ginning machinepicked and machine-stripped cotton have

evolved. These recommendations are primarily

for ginning ü-inch to li/a-inch White and

Light-Spotted cotton, but the principles apply

to all cotton. Even though recommendations

were developed using experimental gin setups

handling three to eight bales per hour, they

have also been found applicable for new highcapacity ginning plants installed in the past 10

or 12 years. Some variation from, or modification of, these recommendations will be necessary in certain areas of the Cotton Belt at

certain times of the year or for special harvesting conditions. High grades will result from

cotton coming from clean fields and harvested

by machines in good condition, while grassy,

weedy fields and poor harvesting practices will

result in lower grades.

MACHINE-PICKED COTTON

Research has shown that machine-picked

Upland cotton varieties from across the Cotton

Belt have similar cleaning characteristics. The

basic ginning recommendation for sequence and

amount of machinery for machine-picked cotton

is as follows:

1. Rock and green-boll trap.

2. Feed control.

3. Tower drier or equivalent.

4. Cylinder cleaner: five to seven cylinders.

5. Stick and green-leaf machine.

6. Tower drier or equivalent.

7. Cylinder cleaner:- five to seven cylinders.

8. Cylinder cleaner: five to seven cylinders

(optional).

9. Feeder, extractor type.

10. Saw gin stand.

11. Saw-cylinder lint cleaner.

12. Saw-cylinder lint cleaner.

13. Press.

The optional cylinder cleaner (item 8) is

recommended for the difficult-to-clean cottons

of the irrigated West. A gin flow chart for

machine-picked cotton is shown in figure 6-1.

MACHINE-STRIPPED COTTON

Because machine-stripped cotton contains 6

to 10 times as much foreign matter as machinepicked cotton, ginning systems in stripper areas

have to be more elaborate than those in picker

areas. Additional extraction equipment is required to cope with large amounts of burs and

sticks which, unless removed, will seriously

lower gin stand performance. Provisions also

have to be made for removing green bolls and

5

^^

FIGURE 6-1.—Recommended gin machinery arrangements for machine-picked cotton.

101
FIGURE 6-2.—Recommended gin machinery arrangements for stripped cotton.

sand from stripped cotton. Green-boll traps and

air-line cleaners located early in the cleaning

sequence perform these functions.

Even though the cleaning characteristics of

stripped cottons vary slightly from variety to

variety, the following array of gin machinery

has been found to be near optimum for most

varieties:

1. Green-boll trap.

2. Air-line cleaner.

3. Feed control.

4. Tower drier or equivalent.

5. Cylinder cleaner: five to seven cylinders.

6. Stick machine.

7. Tower drier or equivalent.

8. Cylinder cleaner: five to seven cylinders.

9. Stick machine.

10. Optional stick machine.

11. Feeder, extractor type.

12. Saw gin stand.

13. Saw-cylinder lint cleaner.

14. Saw-cylinder lint cleaner.

15. Press.

The optional stick machine (item 10) is

Effects of Gin Machinery on

Cotton Quality

By ANSELM C. GRIFFIN, JR.

Cotton possesses its highest fiber quality and

best potential spinning performance when it is

on the stalk. Lint quality of the cotton in the

bale coming from the gin press depends on

many factors, including (1) variety of cotton,

(2) soil type and weather conditions, (3) culrecommended only for stripped cotton containing in excess of 32 percent foreign matter. This

range of foreign matter content is approximately equivalent to a lint turnout of 22 percent

or less. A flow diagram of the recommended

machinery for a stripper gin is shown in

figure 6-2.

BYPASSES

The recommendation above represents the

maximum amount of machinery that should be

needed. Obviously, any machinery which is

not necessary for the particular lot of cotton

should be bypassed. Driers, seed-cotton cleaners

and extractors, and lint cleaners should be provided with bypasses to allow selection of less

drying, cleaning and lint cleaning when extraclean, dry cotton is brought to the gin. For

example, hand-picked cotton now represents

less than 1 percent of the total crop, but may

be significant in a few areas. Appropriate bypasses should be used in handling this cotton,

especially if it is clean and dry. Also, in irrigated areas, certain varieties have better cleaning characteristics, which often require use of

only one lint cleaner to produce satisfactory

quality. Special market conditions will sometimes influence the amount of equipment used,

also.

A necessary part of the ginning machinery

recommendation is that the driers should be

adjusted to produce lint at the gin stand with a

moisture content from 7 to 8 percent. Research

has shown that cotton at this moisture level is

more able to withstand tensile stresses without

breaking than cotton at lower moisture

contents.

Judicious use of the gin machinery combinations discussed here should yield good returns

to the producer and provide grades acceptable

to the spinning mills.

tural and harvesting practices, (4) moisture

and trash content, and (5) ginning treatments

and processes. Usually, the first four factors

exert greater influence on lint quality than

extremes in ginning treatment.

Nevertheless, any mechanical handling, up

to and including spinning, may modify the

natural qualities or characteristics of cotton.

Ginning is a series of thermopneumatic and

mechanical processes and, at best, can only

102
preserve qualities and characteristics inherent

in the cotton when it enters the ginning plant.

Lint grade, staple length, fiber fineness and

maturity (micronaire), and fiber strength—in

the order listed—are the factors that determine

the selling price of cotton. Lint grade is determined principally by color and amount of

foreign matter present. Ginning processes may

do little to change the color of cotton, and they

can change the staple length to only a limited

extent. Ginning does not affect fineness and

maturity.

In addition to its principal function of separating lint from seed, the modern cotton gin

is equipped to remove from the cotton a large

percentage of the foreign matter that would

significantly reduce the selling price of the

ginned lint. Today's ginner must have a twofold

objective: (1) to produce ginned lint of grades

satisfactory to the grower and (2) to gin the

cotton with minimum reduction in fiber spinning quality, so that it will meet the demands

of its ultimate users, the spinner and the

consumer.

Research has shown that, above certain

limits, the strength of individual fibers decreases as the fibers become drier and warmer

and that, for a given quantity of gin machinery,

increased drying may increase fiber breakage

and thus reduce length uniformity.

Yarn strength, yarn appearance, and spinning-end breakage are three of the most

important spinning quality elements. All are

affected by length uniformity and, therefore,

by the proportion of short or broken fibers.

These three elements are usually preserved best

when cotton is ginned with minimum drying

and minimum use of other gin machinery.

The relations between gin drying, lint grade,

yarn strength, and yarn appearance are shown

in figure 6-3. Grade increases attributable to

drying come from two sources. The grade increase that occurs when moisture is reduced

from above 7 to about 7 percent is due to

moving from rough to smooth preparation.

As the fiber moisture content goes below 7 percent, foreign matter removal by the cleaners

increases, but at a declining rate, so there is no

real advantage to lint grade by drying below

the 5-percent fiber-moisture level.

Yarn strength continuously decreases as drying increases (or as the fiber moisture content

decreases) because of the increased amount of

8 7 6 5 4 3

Lint moisture, percent

FIGURE 6-3.—Effects of gin drying on lint grade, yarn

strength, and yarn appearance.

0 7 13 20

Overhead cleaning cylinders

FIGURE 6-4.—Effects of seed-cotton cleaners on lint

grade and yarn strength.

7 13 20

Overhead cleaning cylinders

26

FIGURE 6-5.—Effects of seed-cotton cleaners on lint

grade and yarn appearance for hand-picked and

machine-picked cotton.

103
Ü I 2

No. of lint cleaners

FIGURE 6-6.—Effect of lint cleaners on lint grade, yarn

strength, and appearance.

short fiber in the ginned lint. Below the 5-

percent moisture level at ginning, the rate of

fiber breakage increases rapidly with corresponding decreases in yarn strength.

Yarn appearance improves with drying up

to a point, because of increased foreign-matter

removal. But the effect of increased short fiber

content (and perhaps other factors) on yarn

appearance outweighs the benefits resulting

from foreign-matter removal.

The effects of seed-cotton cylinder cleaners

on lint grade, yarn strength, and yarn appearance are shown in figures 6-4 and 6-5. As the

number of cleaning cylinders increases, the

lint grade usually increases. The cleaning

efficiency of each cylinder is relatively constant; less foreign matter is removed and less

grade improvement is expected from each succeeding cylinder. Twelve to fourteen cylinders

are considered adequate when two lint cleaners

are used and the cotton is dried to the 5- to

7-percent fiber moisture level. The first cleaner

should not have more than seven cylinders, to

prevent roping of inadequately dried seed cotton. The yarn strength decreases steadily as the

number of cleaning cylinders increases.

For cleanly picked cotton, the yarn appearance curve also shows a steady downward trend

because of the machined effect, whereas the

machine-picked cotton curve shows an upward

trend because of foreign-matter removal, until

the machined effect overrides the foreignmatter effect at about 13 cylinders.

The effect of lint cleaning on lint grade, yarn

6 Cyl

0 LC.

:-;-::: '~---.

^^

—

^

^^^^^^^.^-^^^^

"* "

^

y

/

1

•<

s

14 Cyl.

I L.C.

14 Cyl.

2 L.C.

20 Cyl.

3 L.C.

FIGURE 6-7.—Effects of seed-cotton cleaning and lint

cleaning on lint grade and yarn quality for cotton

of two fiber-moisture levels during gin processing.

Yarn quality includes yarn strength, yarn appearance, and spinning breakage.

strength, and yarn appearance is shown in

figure 6-6. Lint grade classification shows some

grade increase as the number of lint cleaners

increases, but each succeeding lint cleaner gives

less grade improvement than the preceding one.

In addition to removing fine trash, the lint

cleaners often blend Light-Spotted cotton so

that it passes into the White grades. The lint

cleaners also remove some short fiber. Hand

stapling and machine measurements often show

a slight increase in length. This length increase

usually reduces manufacturing waste but has

little, if any, effect on yarn strength.

Yarn appearance is usually affected adversely

by lint cleaner treatment. The effect is usually

slight when only one or two lint cleaners are

used, but appearance declines rapidly as

additional cleaners are used.

The overall effect of ginning processes on

grade and yarn quality is shown by figure 6-7.

This chart shows the effects of gin drying and

four different combinations of machinery on

lint grade and yarn quality. Because of the

usually rapid decline in lint grade improvement

and in yarn quality after the 14-cylinder and

2-lint-cleaner combination is used, that combination is recommended as the maximum ginning machinery compatible with acceptable

yarn quality. Use of this machinery combination results in little grade improvement in

low-moisture cotton as compared to high-moisture cotton, whereas the spinning quality of

low-moisture cotton rapidly decreases as

additional machinery is used.

104
SECTION 7.-MISCELLANEOUS CONSIDERATIONS

Fuel Value of Gin Wastes

By ANSELM C. GRIFFIN, JR.

The fuel value of a material is also known

as its calorific value, heat content, or heat of

combustion. All these terms refer to the amount

of heat liberated by a unit mass of a material

when it oxidizes. The gross heat of combustion

may be obtained by using an oxygen bomb

calorimeter; the gross value is then converted

to a net heat of combustion value at normal

atmospheric pressure. The net heat of combustion value is thus considered the same as

fuel value.

Heat of combustion values were determined

in 1973 at the U.S. Cotton Ginning Research

Laboratory, Stoneville, Miss., for gin wastes

from machine-picked cotton harvested from

mid-October to mid-December (table 7-1).

These values may be considered typical for

Upland cotton, and the mean value of 7,928

Btu per pound is useful as an overall average

for dry ginning wastes.

To apply these data, one must take into

account the moisture content of the material

at the time it is incinerated. For example, if the

boll hulls have a moisture content of 16 percent

when cotton is ginned, their fuel value would

be less than the tabular value of 8,194 Btu per

pound. The proper value may be easily found

by converting the moisture content (wet basis)

to moisture regain (dry basis) and making a

correction to the tabular value by using

equations 1 and 2.

Moisture content (M) may be converted to

moisture regain (R) by the formula

ß = 100M/(100-M), (1)

where ß=moisture regain (dry basis) in percent

and M=moisture content (wet basis) in

percent.

For example, when Ai=16, «=1600/84.0=19.

The fuel value of ginning wastes at a specified moisture content may be calculated from

table 7-1 by using the formula

where

and

Hß = 100H^/(1004-Ä), (2)

if^=fuel value at specified moisture

regain in Btu per pound,

i/^=fuel value of dry material (table

7-1) in Btu per pound,

ß=moisture regain in percent.

For example, when boll hulls have a moisture

content (wet basis) of 16 percent, their fuel

value will be Ííi9=819,400/119.0==6,886 Btu

per pound. Thus, the moisture content of hulls

may have a considerable effect on their fuel

value.

The fuel value of other types of ginning

wastes at the time of incineration may also be

calculated by using equations 1 and 2. If we

arbitrarily assume certain moisture contents

for the materials listed in table 7-1 and calculate their fuel values on that basis, more

realistic values are obtained (table 7-2).

TABLE 7-1.—Heat of combustion values for dry

specimens of cotton-gin tvastes from

machine-picked cotton, Mississippi Delta

crop of 1973^

Heat of combustion^

Type of waste (Btu/lb)

Leaf 7,831

Lint 7,758

Sticks, stems, and hulls 8,194

Mean 7,928

1 Average of samples from 3 harvestings collected at

6 locations within the gin.

2 Net value equivalent to fuel value.

TABLE 7-2.—Fuel value of cotton gin wastes

at specified moisture contents, Mississippi

Delta machine-picked cotton, crop of 1973

Type of waste

Moisture

content

(pet)

Fuel

value

(Btu/lb)

Leaf 12 6,893

Sticks, stems, and hulls 16 6,886

Lint and motes 11 6,902

105
TABLE 7-3.—Type and quantity of ginning wastes and their fuel values

obtained from Mississippi Delta spindle-picked cotton and Texas High

Plains stripper-harvested cotton per 500 pounds of lint ginned

Spindle-picked

Type of waste Quantity^ ^°'f"^f ^"^\

/1K\ content! value2

^^^^ (pet) (Btu)

Leaf 21 12 144,800

Sticks, stems, and

hulls 35 16 241,000

Motes and lintcleaner waste 42 11 289,900

Total 98 77^ 675,700

1 Estimated from various laboratory observations.

" Rounded to nearest hundred.

Stripper-harvested

Quantity!

(lb)

Moisture Fuel

content! value^

(pet) (Btu)

100

570

30

11

12

10

696,700

4,111,400

209,500

700 5,017,600

Because ginnery production rates are customarily measured in units of bales per hour, it

is useful to calculate ginning waste fuel values

in units of Btu per bale so that these data may

be readily converted to Btu per hour by simply

multiplying the per-bale heat content by the

ginning production rate. Thus, it is necessary

to take into account the actual quantities of

gin wastes as well as their type and moisture

content. For example, a typical machine-picked

bale in the Mississippi Delta area might contain about 100 pounds of waste, of which about

one-third would be sticks, stems, and hulls at

a 16-percent moisture content; whereas, a

stripper-harvested bale might contain 700

pounds of waste, with about 570 pounds being

sticks, stems, and hulls at 12-percent moisture

(table 7-3). By applying the data of table 7-1

to typical ginning wastes and using equations

1 and 2, the wastes from first-pick spindleharvested and stripper-harvested bales may

be shown to have fuel values of approximately

675,700 and 5,017,600 Btu, respectively.

A quick method of estimating the fuel value

of ginning wastes is to multiply the estimated

quantity of ginning waste by 0.87 (to adjust

for moisture content) and by 7,900 (an overall

value for the fuel value of dry ginning wastes).

Thus, 98 times 0.87 times 7,900 gives 673,600

Btu as the fuel value for gin trash from a bale

of first-pick spindle-harvested cotton, and 700

times 0.87 times 7,900 gives 4,811,100 Btu as

the fuel value of ginning waste from a bale

of stripper-harvested cotton.

Fire Prevention Considerations

By J. E. VAUGHN

Cotton and cotton products are important

links in the chain of our national economy and

care must be exercised to preserve and protect

this product of nature against needless loss.

One peril causing staggering losses to this commodity each year is fire. Thus, fire prevention

and fire protection are of ever-increasing importance in maintaining the position of cotton

and cotton products at the marketplace.

Fire-insurance premiums on cotton gins and

cotton products reflect the fire losses suffered

by the industry. Preventing fires, then, is an

important consideration in keeping insurance

costs to ginners and manufacturers to a minimum, as well as in protecting employees from

injury and avoiding economic dislocation in

the community.

To prevent inordinate economic loss to individual ginners and plant owners in case a fire

does occur, it is important that plant, machinery, and products be reevaluated periodically to

determine that these values and investments

are adequately insured. Consultation with the

insurance carrier is advised on this and other

matters pertaining to coverages.

Fire insurance inspection and rating organizations located throughout cotton-growing areas

and insurance company underwriters should be

consulted on matters pertaining to arrangement or layout, construction, hazard control,

and protection. Standards prescribed for cotton

106
gins are fundamentally the same in all cottongrowing areas, but they may vary in detail.

Detailed information on the following items

pertaining to fire prevention and protection

may be obtained through the inspection and

rating organization having jurisdiction in your

State. For safety-to-life features and compliance with OSHA standards, you should consult

with experts in those fields.

ARRANGEMENT OR LAYOUT

Auxiliary buildings,—These buildings should

be located at a minimum of 40 feet (clear

space) from the gin building.

Open cotton-storage yards,—These yards

should be located at least 200 feet from gin

yards or structures.

Entire gin plant,—The entire plant should

be separated from outside exposures (structures

not a part of the gin plant and highways) as

far as is economically feasible.

CONSTRUCTION

Buildings.—Buildings should be constructed

of fire-resistant and noncombustible material,

securely erected. Buildings so erected have a

materially lower fire insurance rate and maintenance cost. Floors, platforms, and decks, as

well as auxiliary buildings and structures,

should also be constructed of noncombustible

materials.

Machinery,—All-metal machinery, installed

in accordance with manufacturer's specifications and arranged so as to be readily accessible

and free from congestion, should be used

throughout.

POWER, LIGHTING, AND HEATING

FACILITIES

Electric iviring and equipment,—Electric

wiring and equipment should be installed in

accordance with National Electric Code (NFPA

No. 70).

Electric motors,—Unless separated from the

ginning section to avoid dust and lint, electric

motors of the type approved for class III

(National Electric Code) should be used.

Internal combustion engines,—Internal combustion engines should be in a separate room,

free from dust and lint. If liquid fuel is used,

it must be supplied by pump and not by gravity.

Exhaust should be discharged to outside of

building with a minimum clearance from

combustible material of 9 inches.

Fuel tanks and piping,—Fuel tanks and piping should be installed in accordance with the

National Fire Protection Association's Standard No. 30, "Flammable and Combustible

Liquids Code.'' If liquefied petroleum gas is

used, comply with NFPA Standard No. 58,

''Storage and Handling of Liquefied Petroleum

Gases," and NFPA Standard No. 54, "Gas

Appliances and Gas Piping."

Heaters,—Open-flame heaters should not be

used. Inspection and rating organizations have

detailed standards for suitable types of heating

arrangements.

Hydraulic press fluids.—Only those hydraulic

press fluids that have the proper quality and

a sufficiently high flashpoint should be used.

(U.S. Bureau of Mines has recommended

certain fluids to avoid explosions and fires.)

SPECIAL HAZARDS

Trash disposal,—Gin trash (burs, sticks, etc.)

should be collected in adequate, noncombustible

hoppers, equipped with cyclone or other type

separators. The trash should be removed as

it accumulates. To avoid a sizable charge for

improper handling, consult your inspection and

rating organization for the proper type of

equipment and location on gin premise.

Heating units for cotton driers,—Heating

units for cotton driers should be installed in a

separate room, free from dust and lint, in

accordance with the manufacturer's specifications. Proper heat and fuel controls are

necessary for fire prevention and quality

control.

PROTECTION

Fire protection for cotton gins varies with

the types of construction, the availability of

water, and the economic factors involved in

each case. Standards for outside and inside

protection and the credits applicable for their

observance are important data and are available

at the State rating bureau.

Outside protection (public or private),—

Standards for outside protection, including the

amount of water available, the size of the

mains, the number of hydrants, and the most

practical layout arrangements, are described

in detail by your inspection and rating organization.

Inside protection,—For inside protection,

casks, pails, and approved types of portable

107
and wheeled extinguishers should be installed

in required numbers (usually based either on

area of building or on number of gin stands)

and should be maintained as prescribed. Extinguishers are '^approved'' for the class of

fires they are expected to combat, as follows:

class A—ordinary combustible fire; class B—

oil fire; and class C—electrical fire. See NFPA

Standard No. 10.

Automatic sprinkler systems,—One important

prerequisite for an automatic sprinkler system

is an adequate water supply. Plans prepared

by a qualified installer for specific systems

should be submitted to the insurance inspection

and rating organization for approval prior to

installation and for field inspection after

installation.

Fixed'type carbon-dioxide systems,—Fixedtype carbon-dioxide systems should be installed

in accordance with prevailing standards. Plans

prepared by a qualified installer should be

submitted to the insurance inspection and rating organization for approval before installation and for field inspection after installation.

Inside standpipe and hose,—Where sufficient

water is available, inside standpipes and hoses

may supplement other protective devices. Consult your insurance inspection and rating

organization for their recommendations.

Magnetic separators,—Magnets used shall be

those listed by Underwriters' Laboratories, to

assure proper strength. Locate as prescribed

by the inspection and rating organization.

ADMINISTRATIVE PRECAUTIONS

For maximum efficiency of production and

minimum fire hazard, premises should be kept

clean and free of weeds and grass.

Machinery and equipment should be installed

as prescribed by the manufacturer and by the

insurance inspection and rating bureau and

should be kept in good working order.

All employees should be trained in the proper

use of all fire-protection equipment. In case of

fire, first the alarm should be given, and then

the rules learned in practice should be applied.

Congestion in yards by trailers and cotton

products should be avoided. A recent development is to bring seed cotton onto the gin yard

in modules containing 8 to 12 bales. Care should

be exercised in arranging the modules in the

yard and until Cotton-Belt-wide standards are

developed, your insurance company underwriters should be consulted as to the preferable

arrangement for a particular yard or situation.

If baled cotton is stored overnight, a minimum of 40 feet of clear space from the gin

building should be provided.

''No Smoking" and ''Restricted Smoking''

signs should be posted in designated areas.

Every precaution should be taken to avoid

fire-packed bales. When a bale is "suspect," all

concerned should be notified.

Gin Safety

By J. H. TONY PRICE

Injuries to cotton gin employees are a direct

result of unsafe work practices and unsafe

conditions existing in the ginning operation.

Employees must be motivated, and trained when

necessary, to observe correct work practices,

which will produce efficient operations as well

as prevent injuries. A well-planned and carefully executed program with the objective of

preventing injuries is as important to good

ginning practice as any other factor in gin

operation.

While safe practices and procedures must be

adapted to fit individual gin operations, emphasis can be placed on two general areas:

(1) inspection of machinery and facilities, and

(2) establishment of contact with employees—

to promote and maintain safe practices and

conditions.

An initial inspection by management should

precede the repair season. Unsafe conditions

should be located and corrections made or the

hazardous area properly identified if repairs

or replacements are not possible. Inspection

should be repeated periodically throughout the

season, with employees encouraged to report

all unsafe conditions they cannot correct.

The establishment of communication with

employees must come from the management

level and is best accomplished at the time the

employee is hired. This personal contact can

furnish the employee with his orientation to

the particular gin operation. Continuous personal contact, making employees aware of management's interest in their well-being, is the

next step in motivating employees to take pride

108
in their work and perform their jobs in a

manner that will promote efficiency and prevent injuries. Weekly meetings with employees

are an additional tool for keeping in touch with

employees and bringing safe work practices to

their attention.

SAFE WORK PRACTICES

Safe work practices that must be observed

by employees in all gins include:

1. Wearing comfortable, close-fitting

clothes. Sleeves should not be rolled and should

fit snugly at the wrists. Gloves should not be

worn in the gin.

2. Treating scratches, cuts, minor scrapes,

and sprains immediately, and seeking professional care for major injuries. At least one

employee should be trained in a certified firstaid course.

3. Keeping all work areas free of trash,

debris, tools, and any objects that obstruct

safe and normal passage. Tools should be returned to designated storage areas or racks

as soon as they are no longer needed.

4. Cleaning up oil and grease slicks as they

appear.

5. Permitting only qualified personnel to

repair and adjust machinery.

6. Making sure that fellow employees are

clear of machinery before power is turned on.

Management should devise a lockout system

that will prevent accidental start of machinery

when repairs are in progress.

7. Seeing that all guards and covers are replaced before a machine is started.

8. Stopping machinery before changing

belts. Belts should not be thrown on or off while

machinery is running, but rolled onto pulleys

and flywheels by hand. Extreme caution must

be used in this operation.

9. Raising gin breast before dumping seed

rolls. Seed should be raked out with a stick

when rolls are dumped.

10. Stopping gin stand before cleaning air

nozzles. Gin stands should not be operated with

exposed saw cylinders.

11. Keeping fingers at least 6 inches from

saw cylinders. When work on saws is necessary,

the power should be shut off. Panels, doors,

or guards should be removed or opened only

after the saw shafts have stopped turning.

12. Keeping press doors closed until the ram

stops. Tramper foot should not be cleaned

while it is in motion and tramper belt should

not be guided by using a stick or rod while it

is in motion.

13. Seeing that turning press is carefully

watched and employees in area are warned of

movement. Presses not equipped with power

turning devices should be pushed with hands

and not shoulders.

14. Using ladders to enter and exit trailers.

Employees handling trailers should not attempt

to guide the trailer tongue by hand and should

stand with their feet clear while handling the

tongue. There must be close visual coordination

between tractor driver and yardman where

trailers are being hooked, moved, or parked.

15. Seeing that motors are shut off while

refueling vehicles.

16. Permitting no riders other than operator

on yard tractors.

SAFE WORK CONDITIONS

Safe work conditions to be maintained in

cotton gins include:

1. Machinery must not be allowed to operate

with worn parts, cracked belts, or defective

chains. Loose fittings and couplings must be

corrected. An unsafe condition which cannot

be corrected or repaired immediately should

be brought to the attention of employees who

will be working in the area.

2. Basic first-aid supplies in a dust-tight

enclosure should be readily available to all

employees.

3. Line shafts and conveyors that cross

normal walkways must be covered. Those at

floor level, unless guarded by location which

will prevent access, should be covered with

removable grids or plates that will support a

minimum weight of 250 pounds.

4. Firefighting apparatus designed for extinguishing textile or electrical fires should be

located in clearly marked areas that have easy

access. The condition of the extinguisher must

be inspected frequently.

5. All belt and chain transmissions should

be guarded to a height of 7 feet above working

levels.

6. Guards should be of strong enough construction so as not to give way or collapse when

leaned on or shoved against.

7. Drives between gin stands may be guarded by barriers which will prevent accidental

or intentional access into the areas.

109
8. Projecting shaft ends must present a

smooth edge and end and not project more than

one-half the diameter of the shaft unless

guarded by nonrotating caps or safety sleeves.

9. Gin stands must be provided with a

permanently installed guard designed to preclude contact with the gin saws while in motion.

10. Moving saws on lint cleaners having

access doors to the saws must be guarded by

bar or grid-type barrier guards that will preclude contact of fingers with saws.

11. A device must be installed on all bale

presses to prevent the upper gates from being

opened while the tramper is operating.

12. Top panels of bur extractors must be

hinged and equipped with a positive latch.

13. A warning device to sound an audible

signal before the gin is started must be installed

in all gins.

14. Catwalks and other elevated work surfaces or passageways must be equipped with

guardrails and toe boards. Newly constructed

guardrails should have a top rail 42 inches

above the work surface and a midrail. Toe

boards 2 to 6 inches in height must be installed

on surfaces 6 feet or more above normal working or passage areas.

15. Stair rails should consist of a top rail

30 inches vertically above the nose of the tread

and a midrail.

16. Ladders should support at each rung a

minimum concentrated load of 200 pounds.

Cages must be provided on ladders more than

20 feet in height.

110

-sir U.S. GOVERNMENT PRINTING OFFICE : 1977 O—232-824







U. s. DEPARTMENT OF AGRICULTURE

AGRICULTURAL RESEARCH SERVICE

HYATTSVILLE. MARYLAND 20782

OFFICIAL BUSINESS

PENALTY FOR PRIVATE USE, S300

POSTAGE AND FEES PAID

U. S. DEPARTMENT OF

AGRICULTURE

AGR 101