Standard Procedures for Foreign Matter

and Moisture Analytical Tests

Used in Cotton Ginning Research

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Agricultural Research Service

UNITED STATES DEPARTMENT OF AGRICULTURE
CONTENTS

Page

Introduction 1

Pneumatic fractionator method 1

Shirley Analyzer method 4

Method of oven drying seed cotton 6

Method of oven drying cottonseed 8

Method of oven drying ginned lint 10

Method of oven drying cotton wastes 12

Washington, D.C. Issued February 1972

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

Washington, D.C. 20402—Price 10 cents

Stock Number 0100-1609
Standard Procedures for Foreign Matter

and Moisture Analytical Tests

Used in Cotton Ginning Research

By JACOB V. SHHa>HERD, research cotton technologist, Agriddtwral

Engineering Research Division, Agricultural Research Service

INTRODUCTION

The primary objective of preparing this handbook is to provide

laboratory technicians of the Agricultural Engineering Research

Division with a set of specific procedures to be followed in analyzing cotton samples for moisture and foreign matter content.

An additional objective, perhaps as important as the first, is to

standardize the procedures for analytical tests at laboratories concerned with cotton ginning investigations.

Some of the tests and procedures described in this handbook are

uniquely associated with cotton harvesting and ginning. Other

tests are patterned after test methods developed and promulgated

by the American Society for Testing and Materials (ASTM).

These methods are not intended to supplant ASTM methods but

rather to make the methods more suitable for ginning research

needs.

PNEUMATIC FRACTIONATOR METHOD

Scope

The pneumatic fractionator method is used to measure the

amount of foreign matter in a sample or lot of seed cotton. The

large particles of foreign matter are removed by hand, whereas

the smaller particles are removed in a machine that uses compressed air to tumble the specimen. The foreign matter is collected

on a series of three screens.

Test Specimen

Either allow fractionation samples to come to moisture equilibrium before testing, or be sure the moisture content of the sample

is 7 percent or less.

The specimen should weigh about 150 grams.
Standard Procedures for Foreign Matter

and Moisture Analytical Tests

Used in Cotton Ginning Research

By JACOB V. SHEa'HíKD, research cotton technologist. Agricultural

Engineering Research Division, Agricttltural Research Service

INTRODUCTION

The primary abjective of preparing this handbook is to provide

laboratory technicians of the Agricultural Engineering Research

Division with a set of specific procedures to be followed in analyzing cotton samples for moisture and foreign matter content.

An additional objective, perhaps as important as the first, is to

standardize the procedures for analytical tests at laboratories concerned with cotton ginning investigations.

Some of the tests and procedures described in this handbook are

uniquely associated with cotton harvesting and ginning. Other

tests are patterned after test methods developed and promulgated

by the American Society for Testing and Materials (ASTM).

These methods are not intended to supplant ASTM methods but

rather to make the methods more suitable for ginning research

needs.

PNEUMATIC FRACTIONATOR METHOD

Scope

The pneumatic fractionator method is used to measure the

amount of foreign matter in a sample or lot of seed cotton. The

large particles of foreign matter are removed by hand, whereas

the smaller particles are removed in a machine that uses compressed air to tumble the specimen. The foreign matter is collected

on a series of three screens.

Test Specimen

Either allow fractionation samples to come to moisture equilibrium before testing, or be sure the moisture content of the sample

is 7 percent or less.

The specimen should weigh about 150 grams.
Equipment

• Balance, direct reading preferred, capacity 500 grams or

more, sensitivity 0.1 gram.

• Fractionator, and three screens : 6, 50, and 200 mesh.

• Brush, soft bristle (2-inch paintbrush).

• Metal tray, 23 by 23 by 1 inch, one end open, 1 to 4 in number.

• Metal pan, 8 by 12 by 1 inch, 1 to 4 in number.

• Automatic timer.

• A compressed air supply capable of maintaining 70 p.s.i. when

fractionator is in operation.

Procedure

Place the fractionation sample and the paper bag on a large

scale pan, and record the weight to the nearest 0.1 gram.

Empty the specimen on a large metal tray, taking care to avoid

loss of foreign matter in removing the sample. Shake the paper

bag mouth down over the removed lot to obtain all the foreign

matter in the sample.

Weigh the paper container to the nearest 0.1 gram, subtract the

weight from the original sample and bag weight, and record on

the laboratory fractionation sheet.

Note,—For seed cotton foreign matter samples weighing

more than 150 grams, the following procedure is recommended : About one-half of the entire large sample is spread

thinly over the balance pan about 12 inches in diameter. The

remaining one-half is then carefully spread over the first half.

Any sifted trash in the large sample container is spread uniformly over the entire sample area. A portion of the sample

consisting of about 150 grams is removed from the center by

pulling the protruding seed cotton away from the pan and

lifting the pan carefully in a vertical direction. The small

sample of approximately 150 grams is weighed and the

weight recorded.

Remove all large foreign matter from the test sample by hand

before fractionation. If desired, separate the foreign matter as to

kind, such as hulls, sticks and stems, and grass.

Place the remaining sample in the fractionator. Set timer for 75

seconds, and start the agitation with the compressed air at 70

p.s.i.

Collect and weigh the combined foreign matter on the three

screens in the base of the machine, and record to the nearest 0.1

gram.

Weigh and record the large trash removed by hand, and record

to the nearest 0.1 gram.
When percentages of each kind of foreign matter are desired,

refractionate the material on the coarse screen ; then pick out the

motes and seeds on the coarse screen, weigh each group, and record the weights. After picking out the motes and seeds, separate

the material left on the coarse screen by fractionation. Weigh the

material on each screen and each kind of large trash separately,

and record on laboratory sheet. The material on the top or coarse

screen is classified as lint; the middle screen, as leaf; and the fine

or bottom screen, as pin trash. Carefully remove all foreign matter from each screen with a small brush.

Weigh the cleaned seed cotton, and record the weight.

Calculations

Calculate the foreign matter content in percent as follows :

F = (Fn/So) 100 (1)

where F = foreign matter content

Fn = foreign matter picked out by hand in grams

So = original seed cotton weight in grams

F = (Fs/So) 100 (2)

where F = foreign matter content

Fs = foreign matter from fractionator screens in grams

So = original seed cotton weight in grams

F = (Fe/So) 100 (3)

where F = foreign matter content of one component

Fc = weight in grams of the component

So = original seed cotton weight in grams

Use equation 3 to calculate each component, such as sticks and

stems, hulls, grass, leaf, motes, and pin trash.

Precision and Accuracy

Based on tests made with 10 observations on each lot, the expected precision in foreign matter percentages for seed cotton was

as follows :

Foreign matter Standard Coefficient

deviation of variation

Removed by agitation 0,5 12.0

Total removed by agitation

and handpicking .7 13.1

The number of observations (tests) required to detect specific

differences between seed cotton samples at the 95-percent probability level was as follows :

3
Specific Total Foreign matter

differences foreign matter specimens

specimens removed by

fractionator

Percent Number

0.3 28

.5 10

.7 5

.9 3

Number^

14

5

^ n = t2s2/d2

where n = number of specimens

t = probability factor (2.262 for 95-percent probability and

and 9 degrees of freedom)

s z=z standard deviation in percentage points

d = difference to be detected

No justifiable statement on accuracy can be made because the

absolute true value of foreign matter percentage in seed cotton

cannot be established by an accepted reference method.

SHIRLEY ANALYZER METHOD

Scope

The lint foreign matter test method is used to determine the

foreign matter content in a sample of lint cotton or processing

waste using the Shirley Analyzer. This method is designed to

obtain accurate lint foreign matter test results in the shortest

possible time. This is accomplished by using smaller test specimens, one pass through the machine, and correction factors for

determining lint foreign matter percentages.^ 2 3

Test Specimen

Take four portions, each about the same size, from four widely

distributed locations throughout the laboratory sample, and weigh

a 50-gram specimen to the nearest 0.01 gram.^ Do not blend or

handle the laboratory sample in such a way as to cause loss of any

foreign matter.

^ SHEPHERD, J. V. NON-LINT CONTENT MEASUREMENT BY THE ONE-PASS

SHIRLEY ANALYZER PROCEDURE. Textile Res. Jour., pp. 75-78. January 1961.

^STONEVILLE COTTON GINNING RESEARCH LABORATORY, ANNUAL REPORT—

FISCAL YEAR 1970. P. 11. 1970.

^ STONBVILLE COTTON GINNING RESEARCH LABORATORY, ANNUAL REPORT—

FISCAL YEAR 1965. Pp. 12-14, 18. 1965.

*STONEVILLE COTTON GINNING RESEARCH LABORATORY, ANNUAL REPORT—

FISCAL YEAR 1959, Pp. 105-110. 1959.
Conditioning

The samples should be conditioned to the atmosphere in the

testing room (TS"" F. and 60-percent relative humidity) for at

least 24 hours before testing.

Equipment

• Shirley Analyzer. See operating instructions for adjustment

and maintenance in ASTM manual.

• Balance, capacity of at least 100 grams, sensitivity of 0.01

gram.

• Set of weights.

• Transparent case, 16 inches wide, 20 inches long, and 18

inches high, to enclose balance.

Procedure

Spread the test specimen as evenly as possible over the feed

table. Large masses of fiber should be pulled apart to make an

even batt.

Set the exhaust valve to obtain the minimum amount of lint

falling into the waste (foreign matter) compartment and a minimum amount of foreign matter (waste) collecting with the lint on

the condenser cage.

Clean the delivery box and waste compartment.

Start the machine and process the test specimen through the

machine.

Collect the lint from the trash pan, shake lightly to remove the

adhering trash, and process through the machine.

Remove the cleaned lint from the compartment, weigh to the

nearest 0.01 gram, then weigh the waste from the foreign matter

compartment to the nearest 0.01 gram and record the weight.^

Note,—For total wastes ranging from 2.9 to 4.1 percent, research done in 1969 showed that 0.31 gram (0.16 gram exhaust lint and 0.15 gram moisture loss) should be added to

the total clean lint weight to correct for moisture and lint loss

during processing.^

Calculations

Calculate to the nearest 0.01 percent the total waste, visible

waste, and lint content using equations 4, 5, and &J^

^ See footnote 1.

<* See footnote 2.

'^ See footnote 3.
T=iW — L) 2.23 (4)

where T = total waste in percent

W = original specimen weight in grams

L = clean lint weight in grams

Note,—To calculate total waste percentage, subtract the clean

lint weight in grams from the original 50 grams and multiply

the results by 2.23, which is the equivalent of adding the

correction of 11.5 percent to the total waste percentage.»

VW=V/WX 100 (5)

where VW = visible waste in percent

V = visible waste collected

W = original specimen weight in grams

LC= 100 —T (6)

where LC = lint content

T = total waste in percent

Precision and Accuracy

The standard deviation and coefficient of variation for 10 total

waste percentages on a large sample of lint, based on 1969-70

data,9 are 0.8 percent and 7.3 percent, respectively. No justifiable

statement on accuracy can be made because the true values are not

known and cannot be established by an independent procedure.

The number of observations (tests) required to detect specific

differences between samples at the 95-percent confidence level ^^

was as follows :

Specimens Total waste differences

Number Percent

12 0.2

5 .3

2 .5

METHOD OF OVEN DRYING SEED COTTON

Scope

These methods cover the procedures for determining the amount

of moisture in seed cotton by oven drying. When moisture is not

® See footnote 3.

• See footnote 2.

^^ See tabular footnote 1, p. 4.
the primary objective of the study, a 2-hour oven drying method

with the formulas for calculating the moisture content may be

used.

Equipment

• Oven, thermostatically controlled in the temperature range of

220° to 230° F., fan-forced ventilation, and, preferably, equipped

with a balance that permits weighing the specimens without opening the ovens.

• Balance, of at least 100 grams capacity and a sensitivity of

0.01 gram, to weigh the specimens.

• Metal baskets, at least 3 inches in diameter by 6 inches high

(75 mm. in diameter by 150 mm. high), for use in rectangular

ovens equipped with revolving arms on which the baskets are

hung. For specimens containing particles of foreign matter that

are easily shaken out, use baskets made of wire screening fine

enough to hold the trash, or line the lower part of the basket with

metal foil, though this technique may prolong the drying period.

• Transparent case, 16 inches wide, 20 inches long, and 18

inches high.

• Set of balance weights.

Five-Hour Procedure

Weigh a seed cotton specimen of about 50 grams from an airtight container, and record the weight to the nearest 0.01 gram.

Note,—Seed cotton containing at least 2 percent moisture will

not change more rapidly than 0.1 percent per minute during

exposure to air at standard temperatures and humidities.

Open the container and weigh out the specimen of 50 grams,

within 0.01 gram. If the specimen is adjusted to the specified

weight in not more than 30 seconds after the container is

opened, no appreciable error is introduced.

Place the specimen and the basket in the oven, and dry at 220°

to 230° F. (105° to 110° C).

Dry the seed cotton for at least 5 hours or until the change in

weight between successive weighings at intervals of at least 1

hour is less than 0.1 percent of the specimen weight. Weigh to the

nearest 0.01 gram and record the weight.

Calculate the moisture content as follows :

M= {Wo—Wa)/Wo X 100 (7)

where M = moisture content

Wo = the original weight of the specimen

Wd = the specimen weight after oven drying
Two-Hour Procedure

Take a specimen of seed cotton from an airtight container, and

weigh 50 grams to the nearest 0.01 gram on a balance in the glass

case. (See previous note under ''Five-hour Procedure.")

Place the weighed specimen in the wire basket, and put in the

hot oven without delay to avoid an error due to change in moisture

content before drying.

After 2 hours drying (while the basket is still in the oven),

weigh to the nearest 0.01 gram and record.

Calculate the moisture content of seed cotton after 2 hours

drying as follows :

Y= 0.66 + 2.25X (8)

where Y = moisture percentage equivalent to 5 hours of

oven drying

X == moisture loss in grams after 2 hours of

oven drying

Precision and Accuracy

Based on tests made with 10 tests or observations on each lot,

the expected precision in moisture percentages for seed cotton is

0.5 percent for the standard deviation and 6.4 percent for the

coefficient of variation. No justifiable statement on accuracy can

be made because the true value of moisture content in seed cotton

cannot be established by an accepted reference method.

The number of observations (tests) required to detect specific

differences between seed cotton samples at the 95-percent probability level is as follows :

Specific difference Specimens

Percent Number

0.3 15

.5 5

.7 3

.9 2

METHOD OF OVEN DRYING COTTONSEED

Scope

This method covers the procedure for determining the amount

of moisture in cottonseed by oven drying for 5 hours and 10 hours.

8
Equipment

• Oven, thermostatically controlled in the temperature range of

220° to 230° F., fan-forced ventilation, and, preferably, equipped

with a balance that permits weighing the specimens without opening the ovens.

• Balance, of at least 100 grams capacity and a sensitivity of

0.01 gram, to weigh the specimens.

• Metal perforated cups, 2V2 inches in diameter and 21/2 inches

high, for use in rectangular oven equipped with revolving arms on

which the cups are hung.

• Transparent case, 16 inches wide, 20 inches long, and 18

inches high.

• Set of balance weights.

Ten-Hour Procedure

Take a specimen of cottonseed from an airtight container, and

weigh out 50 grams to the nearest 0.01 gram on a balance in the

case.

Note.—Cottonseed containing at least 2 percent moisture will

not change more rapidly than 0.1 percent per minute during

the exposure to air at standard temperatures and humidities.

Open the container and weigh out the specimen of 50 grams.

If the specimen is adjusted to the specified weight in not more

than 30 seconds after the container is opened, no appreciable

error is introduced.

Place the weighed specimen in the perforated cups and put in

the oven for drying.

Dry the cottonseed for at least 10 hours or until the change in

weight between successive weighings at intervals of at least 1

hour is less than 0.1 percent of the specimen weight.

Weigh the specimen, while the basket is still in the oven, to the

nearest 0.01 gram and record.

Use equation 7 to calculate the cottonseed moisture content for

10 hours of oven drying.

Five-Hour Procedure

Take a specimen of cottonseed from an airtight container,

weigh out about 50 grams to the nearest 0.01 gram on a balance in

the glass case, and record the weight. (See previous note under

**Ten-hour Procedure.*')

Place the weighed specimen in the perforated cups, and put in

the oven without delay to avoid an error due to change in moisture

content before drying.

Weigh the cottonseed specimen, while the basket is still in the

oven after 5 hours of drying, to the nearest 0.01 gram and record.
Calculate the cottonseed moisture content after 5 hours of oven

drying as follows :

Y=1.95Z + 0.81 (9)

where Y = moisture percentage equivalent to 10 hours of

oven drying

X = moisture loss in grams after 5 hours of

oven drying

Precision and Accuracy

Based on tests made with 10 tests or observations on each lot,

the expected precision in moisture percentages for cottonseed is

0.4 percent for the standard deviation and 4.3 percent for the

coefficient of variation. No justifiable statement on accuracy can

be made because the true value of moisture content in cottonseed

cannot be established by an accepted reference method.

The number of observations (tests) to detect specific differences

between cottonseed samples at the 95-percent probability level is

as follows :

Specific differences Specimens

Percent Number

0.3 9

.5 3

.7 2

.9 1

METHOD OF OVEN DRYING GINNED LINT

Scope

This method covers the procedure for determining the amount

of moisture in ginned lint delivered to the laboratory.

Equipment

• Oven, thermostatically controlled in the temperature range of

220° to 230° F. (105° to 110° C), fan-forced ventilation, and,

preferably, equipped with a balance that permits weighing the

specimens without opening the ovens.

• Balance, of at least 100 grams capacity and a sensitivity of

0.01 gram, to weigh the specimens in the containers that will be

used.

• Metal baskets, at least 3 inches in diameter by 6 inches high

(75 mm. in diameter by 150 mm. high), for use in rectangular

10
ovens equipped with revolving arms on which the baskets are

hung. For spacimens containing particles of foreign matter that

are easily shaken out, use baskets made of wire screening or with

openings fine enough to hold the trash, or line the lower part of

the basket with metal foil, though this technique may prolong the

drying period.

• Transparent case, 16 inches wide, 20 inches long, and 18

inches high.

• Set of balance weights.

Procedure

Take ginned lint specimens weighing about 20 grams from an

airtight container. Weigh specimen to the nearest 0.01 gram on a

balance in a glass case and record the weight.

Note.—Lint containing at least 2 percent moisture will not

change more rapidly than 0.1 percent per minute during exposure to air at standard temperatures and humidities. Open

the container and weigh out the specimen of 20 grams. If the

specimen is adjusted to the specified weight in not more than

30 seconds after the container is opened, no appreciable error

is introduced.

Place the specimen in the perforated baskets and put in the

oven for drying.

Dry ginned lint for at least 60 minutes or until the change in

the weight between successive weighings at intervals of at least 15

minutes is less than 0.1 percent of the specimen weight.

Weigh the specimen, while the basket is still in the oven, to the

nearest 0.01 gram and record the weight.

Calculations

Use equation 7 to calculate the lint moisture content after 60

minutes of oven drying.

Precision and Accuracy

Based on tests made with 10 tests or observations on each lot,

the expected precision in moisture percentages for ginned lint is

0.3 percent for the standard deviation and 5.9 percent for the

coefficient of variation. No justifiable statement on accuracy can

be made because the true value of moisture content in ginned lint

cannot be established by an accepted reference method. The number of observations (tests) required to detect specific differences

between samples at the 95-percent probability level is as follows :

11
Specimens Specific differences

Percent Number

5 0.3

2 .5

1 7

METHOD OF OVEN DRYING COTTON WASTES

Scope

This method covers the procedure for determining the amount

of moisture in cotton wastes by the oven drying method. Cotton

waste is the material removed from seed cotton, ginned lint, or

stock in process by any cleaning or processing machinery and is

usually a mixture of seed cotton or cotton fibers with foreign

matter.

Equipment

• Oven, thermostatically controlled in the temperature range of

220° to 230° F., fan-forced ventilation, and, preferably, equipped

with a balance that permits weighing the specimens without opening the cans.

• Balance, of at least 100 grams capacity and a sensitivity of

0.01 gram, to weigh the specimens.

• Metal perforated baskets, at least 3 inches in diameter by 6

inches high (75 mm. in diameter by 150 mm. high), for use in

rectangular ovens equipped with revolving arms on which the

baskets are hung. Use baskets made of wire screening or baskets

with openings fine enough to hold the waste, or line the lower part

of the basket with metal foil, though this technique may prolong

the drying period.

• Glass case, 16 inches wide, 20 inches long, and 18 inches high.

• Set of balance weights.

Procedure

From waste containing less than 50 percent lint cotton, cottonseed, or seed cotton, take specimens weighing 50 grams for the

oven balance procedure. These specimens should come from an

airtight container and be weighed to the nearest 0.01 gram on a

balance in a glass case.

Note,—Waste containing at least 2 percent moisture will not

change more rapidly than 0.1 percent per minute during ex12
posure to air at standard temperatures and humidities. Open

the container and weigh out the specimen of 50 grams. If the

specimen is adjusted to the specified weight in not more than

30 seconds after the container is opened, no appreciable error

is introduced.

Place the specimen in the baskets, and put in the oven for

drying.

Dry waste containing less than 50-percent lint cotton, cottonseed, or seed cotton for at least 5 hours or until the change in

weight between successive weighings at intervals of at least 1

hour is less than 0.1 percent of the specimen weight.

Weigh the specimen, while the basket is still in the oven, to the

nearest 0.01 gram and record.

Calculations

Use equation 7 to calculate the waste content of moisture.

Precision and Accuracy

Experience with this method is limited. Therefore, currently,

well-established levels of expected precision are not available.

No justifiable statement on accuracy can be made because the

true value of moisture content in waste cannot be established by

an accepted reference method.

^U.S. GOVERNMENT PRINTING OFFICE: 1972 0—443-789

13