A full view of the maintenance vehicle is shown in Photograph 2
below. Note the gasoline cans at rear of the trailer. Also note

the arc and acetylene welding equipment are mounted just behind
the cab for stability.

Photograph 2. Photo PX-D-67504

The service unit is powered by a 1963-1/2 ton pick-up truck. Con-
siderable skill and adaptation was required to combine the trailer
and pick-up into a semi-truck. All labor was done by district
employees. Parts to build this unique unit totaled $704.

If further information is desired regarding this vehicle you may
write to the Exeter Irrigation District, P. 0. Box 546, Exeter,
California 93221.

tk RR

The great inventors have been the great surprisers. Again
and again they have shamed our limited outlook. They have
done the things we have said could not be done. They have
been experts in the impossible.

17


To relieve the pressure of the wheels on the axle the hydraulic jack
that is built into the jack-cart is so used, thus making the wheels

easier to remove. This hydraulic jack is shown being operated by
the mechanic in Photograph 2 below.

Photograph 2. Photo PX-D-67501

The jack-cart can be rolled back, completely out of the way of the
mechanic as shown in Photograph 3 below, until the wheels are ready
to be replaced.

Photograph 3. PX-D-67502

a aed

ll


damage has been limited in nearly all cases to the breaking of the
oil line to the lower bearing. The repair of this line is usually
a relatively simple matter, and it is generally felt that a saving
has resulted from permitting the pumps to remain in place during the
winter.

For the guidance of our operators and maintenance personnel, the
following suggestions are offered relative to the treatment of
pumps allowed to remain in place in wet sumps during prolonged cold
weather below freezing conditions:

1. Pumps are not specifically designed to withstand stresses
which might result from being permitted to freeze-in so it
must be realized that there is a calculated risk involved.
Damage suffered by the machine as a result of freezing-in can-
not be attributed to any deficiency in design.

2. If pumps are allowed to freeze-in, a careful inspection of
the lubrication line to the lower bearings of vertical units
should be made prior to operation.

3. Consideration should be given to any protective measures
which might prevent the formation of heavy ice in the sump or
which might minimize damage to the pump in case of freeze-in.

Remember that even a drained sump in a drained canal or pipe line
may accidently flood from unexpected causes. Consequently, they
should be inspected occasionally during freezing weather.

Horizontal Centrifugal Pumping Units

Horizontal centrifugal, double-suction, split-case pumps have inter-
nal cavities that may become filled with water during operation;
these may not drain upon shutdown at the end of the irrigation sea-
son. The two main cavities are the cored cavities in the suction
volute and the interior of the double-suction impeller.

The cored suction volute cavities are normally filled with concrete
or grout during shop assembly in the manufacturer's plant or at the
time of installation at the site. Sometimes the manufacturer will
provide drain holes to these cavities, but during operation the
drain holes may become plugged with debris and fail to permit the
cavity to drain. When the pump has been opened for routine inspec-
tion and maintenance at the end of the irrigation season these cav-
ities, if present, should be checked to see if they have been filled
or are draining properly. If the drains were provided a check to
see if they could become plugged and, if so, they should be filled
as noted above to prevent possible freezing damage.

21


Crack and Joint Fillers and Sealers

Since cracks in concrete lining are always caused or associated with
movement of the slab, it is essential to seal them with a flexible
material, one which will remain flexible and bond to the concrete.
This is essential if a canal is to effectively fulfill its purpose
for watertightness. Also, a good seal will prevent entrance of sand
and silt into the cracks, thereby preventing excessive stress in the
lining when expansion occurs.

Damage from Back Pressure or Subgrade Conditions

For the repair of concrete lining where damage has occurred from back
pressure or unstable subgrade conditions, several methods of repair
and types of joints are sometimes necessary. The following drawing
illustrates the replacement of a section of lining where back pres-
sure results in damage and part of the lining must be replaced. In
the drawing below note the 5:1 protective slope above the lining and
the sandy-clay material placed near the top. This will prevent water
from getting in behind the lining from above.

Sandy-clay or
gravelly-clay material

6' Well graded sand and gravel
with 100% passing if sieve and
less than 5% passing the
*200 sieve.

Flap valve weep. Place weeps in
a j2'e. the center of each 15’ panel.

LINING REPAIR WHERE BACKPRESSURE EXISTS
FIGURE |


BATTERIES FOR REMOTE VHF RADIO REPEATERS

Under very cold weather conditions the selection of the correct type
of battery is essential for VHF radio repeaters that are equipped
with engine-cranking batteries to start standby power units.

At about -30° Fahrenheit the water in the electrolite of a lead acid
battery starts to freeze. Ice crystals start forming and the crank-
ing power becomes nil. On the other hand nickel-cadmium batteries
under these same temperature conditions retain some of their volt-
age and output capacity so that cranking is not impaired. Voltage
at low temperatures is more important than ampere-hours. A bank

of lead acid station batteries is shown in Photograph 1 below, and
in Photograph 2 on the next page, shows a typical nickel-cadmium
battery.

Photograph 1. Photo PX-D-67505

Nickel-cadmium batteries are particularly suited for communications
systems and other applications requiring many hours of discharge,
at a constant current. However, selection of a battery will depend
to a large extent on how the repeater station is made up and also
the temperatures to be encountered. The best solution to the bat-
tery problem of course, is a warm building.

18


WINTERIZING OF IRRIGATION PUMPS 1/
Introduction

The Bureau of Reclamation has installed a great many irrigation
pumps of all sizes in various locations, which operate over a large
range of climatic conditions. The question of winterizing these
pumps arises quite regularly. For instance, on many of our proj-
ects it is customary to permit vertical pumps to remain in the
water in normal operating position throughout the winter months,
and on others the pumps are removed from the water every year
before freeze-in.

Vertical Wet Sump Pumping Units

A wet sump pumping plant normally is one in which vertical-shaft
pumping units are suspended from a deck and the pumping element
is submerged in a sump. The sumps may be of the propeller (axial
flow), mixed-flow, or vertical-turbine (radial flow) type.

Several installations have horizontal centrifugal, double-suction,
split-case pumps which are of the bottom-suction type, which also
may be classified as wet sump pumps. These are protected the same
as discussed later under Horizontal Centrifugal Pumping Units.

The need for special steps, procedures, and precautions necessary
to avoid or prevent damage to pumps due to freezing action when
allowed to remain in wet sumps has been considered by operation
and maintenance personnel on our colder northern projects for many
years. On numerous projects considerable effort is expended to
assure that no damage will occur. llowever, on a greater number
of projects only very minor preventive measures are taken.

In order to determine what procedures or precautions, if any, are
necessary or required to avoid freezing damage to this type of
pump, a questionnaire was prepared and distributed to our north-
ern regional offices. The information obtained from the returned
questionnaires was tabulated and studied.2/

We learned from the information provided that damage to pumps from
ice in the pump sumps has occurred in a few instances, but this

1/ Written especially for this publication by Mr. Wesley W. Beck,
Supervisory Mechanical Engineer, Division of Design, Office of
Chief Engineer, Denver, Colorado.

2/ Winterizing of Wet Sump Pumping Plants, a memorandum report by
Mr. J. F. Buchheim, Engineer, Division of Irrigation Operations,
Office of Chief Engineer, Denver, Colorado, dated February 19, 1965.

20


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15


Random cracking also may occur in concrete canal linings. Figure 7
below, shows a random crack and how a sealer can be applied. Note
that the sealer over the crack must be not less than 3/8 inch thick.
This thickness is very important and must be attained if the repair
is to be successful. The drawing indicates sandblast cleaning which
is the best and most economical method of securing a clean and suit-
able bonding surface.

-*——— Sandblast entire area

Concrete lining——~-

SECTION THRU RANDOM CRACK
FIGURE 7

Polysulfide

A coal-tar modified polysulfide (two component) sealer has superior
weathering resistance. Adhesion to clean dry concrete is excellent,
but not to wet or damp concrete. Specifications require it to resist
extrusion through a 1/8-inch crack under 60 foot of head for 7 days;
therefore, backup material is not needed except in wider cracks. It
can be used for sealing both random cracks and contraction grooves.


Strengthening ribs

Vibrate to ensure filling of
voids mith concrete.

TOP VIEW SECTION
SROREAES COMPANION FLANGE

Pr a
‘SCALE OF INCHES

@ 4° Round head brass machine screw
f with 1°00 174° thick brass washer
a° Bross cop screw ‘ond bross nut
with Her heod ond ff
brass wosher ©

® Brass disk 4" minimum thickness

Thick neoprene rubber flop
DOWN SLOPE with shore ‘A’ durometer of 50
to 70

-© Plastic componion fionge

1g” 1.0. Plostic pipe |
nipple - ————- ——

-'13" Slots, eoch bond,
equally spaced

Drill ond top for 3°
cop screw

Provide 74" Mor. ¥,. Min.
height sealing ring. |

DETAIL OF PARTS
(FLAP VALVE)
MO SCALE

SECTION A-A

(FLAP VALVE WEEP)

Figure 2



A flap valve weep near the toe of the side lining is shown in the
drawing on the preceding page. This is essential to the elimina-
tion of hydrostatic back pressure against a concrete lining. The

following two photographs and Figure 2 on the next page show flap-
valved weeps in detail.

Photograph 1. Photo PX-D-67498

Photograph 2. Photo PX-D-67499


ALL PURPOSE MAINTENANCE VEHICLE 1/

Efficiency in maintenance of the Exeter Irrigation District has
been increased by the use of an unusual vehicle designed by and
constructed under the supervision of their district superintendent,
Mr. Harvey Sandidge. Many time consuming trips from problem areas
to the shop for equipment or tools necessary to solve a maintenance
problem are now eliminated by use of this vehicle.

Equipment mounted on the trailer includes arc and acetylene weld-
ers, air compressor, water pump, tool cabinet, pipe vise, standard
vise and lubricating equipment. Five steel boxes are also mounted
on the trailer that contain tools, welding accessories, meter and
gate valve parts and parts essential for pipeline repairs.

Photograph 1 below shows the tool boxes mounted at rear of the
trailer. Air compressor and water pump can be seen just behind
the cab. Twenty gallons of gasoline are available for other dis-
trict equipment, if required. The vehicle is also equipped with
a two-way radio.

Photograph 1. Photo PX-D-67503

1/ Article submitted by Mr. Floyd Brown, of the Exeter Irrigation
District, Exeter, California.

16


Most joints and grooves in concrete linings will be of the weakened
plane type, as discussed previously and filled with an elastic fil-
ler or sealant. Figure 5 below, illustrates a typical groove. It
has been found that the groove must be at least one-third the depth
of the lining if adequate weakness is to be attained and random crack-
ing avoided. Also, sealer depth of 5/8 inch is considered a minimum.
Groove width must be large enough that extension or compression of
the sealer will not exceed about 25 percent, otherwise the sealer

may fail. A suggested table of dimensions for groove, width, depth,
and spacing is given in Figure 6 below.

Weakened stance

Polysulfide sealant

| F-2'min.

Lae L

[+
WEAKENED PLANE JOINT
FIGURE 5
GROOVE DIMENSIONS
T 8 c APPROXIMATE
eHnNESS GROOVE WIDTH|GROOVE DEPTH WN Gehreee
(INCHES) (INCHES) (INCHES) (FEET)
2 Ztoy gtos 10
Cy gtos Ztot 10
3 Ztot Itoi 12 to 15
at tot I¢tolt 12 to 15
| 4 Stot IZtold 12 to 15
FIGURE 6


The central hub of a double-suction impeller is generally cored out,
especially in large impellers, to avoid a heavy cross-section that
might lead to porous or imperfect castings. On occasion water can
enter this cavity by following along the shaft, filling the cored
area, and not being able to drain back. If this cored cavity is
filled with water and freezing takes place, a frost-boil at the
weakest point of the central hub will usually result. This action
could damage the impeller beyond repair.

Recent U.S. Bureau of Reclamation specifications require that these
openings be filled or provided with suitable drains at the factory.
If drains are provided they are normally 120° apart, but here again
they may become plugged with debris and fail to adequately drain
the cavity.

On older pumps it may be rather difficult to tell if a problem
exists. If the pump has been installed for several years and been
exposed to below freezing temperatures and no trouble has developed,
you probably have no problem. Two customary ways of inspecting this
cavity are during routine maintenance to remove the impeller from
the shaft or drill a small hole into the cavity which can also be
used to fill the cavity, if necessary, and then plugged and ground
smooth to contour.

It is suggested that if in doubt, the impeller cored cavity be
filled with a plastic foam, a mixture of beeswax and sawdust, or

any suitable light weight material that will absorb the expansion
of the water when frozen.

ed

22


United States Department of the Interior, Bureau of Reclamation

»SHRRIGATION OPERATION AND MAINTENANCE

= BULLETIN NO. 73
4 July, August, September 1970
—_—

[——]

=

i——]

—|

4

=>

S

| eka

=

_ In This Issue:

Repair of Concrete Canal Lining
_  Jack-Cart for Dual-Wheel Truck Servicing

Portable Power Cords for Use in Maintenance and Emergencies
Sandblast Gun Modification

All Purpose Maintenance Vehicle

Batteries for Remote VHF Radio Repeaters
Winterizing of Irrigation Pumps


Other Sealing Compounds

Asphalt mastic sealers have been used by the Bureau for many years
for sealing joints and cracks in concrete canal linings. The one
in use for the past 10 years is low in cost, can be applied as
received, is more elastic than previous asphalt mastics, is most
durable where continuously submerged or otherwise protected from
direct weathering, and has been found to provide a satisfactory
seal for about 5 years, depending on service conditions. Experi-
ence has shown that it will adhere satisfactorily under less than
ideal conditions, i.e. damp concrete, less thorough surface prepa-
ration, or application over other deteriorated asphalt sealers. It
is however, less weather resistant than polysulfide sealers and,
being essentially plastic in nature, it may be extruded through
cracks as narrow as 1/16 inch under hydrostatic pressures greater
than 6 feet of water.

Where the sealer is to be used in contraction joints under high
pressures a backup material such as butyl sponge rod should be
installed at the bottom of the groove, leaving a channel above the
backup at least 3/4 inch deep to receive the mastic. It is not
recommended for sealing cracks under high heads. Under low heads
it is vital that the mastic bead be applied over the crack to a
depth of at least 3/8 inch to prolong its life. It should be
pointed out that, this mastic is more satisfactory for sealing con-
traction joints than for sealing random cracks because cracks tend
to reflect through. Glass cloth reinforcement, such as is used in
the tape described above, would probably significantly improve the
crack sealing ability of this mastic.

The three sealing materials mentioned above can be obtained from
many contractor supply houses. However, if specifications or fur-
ther information is desired, please write to: Department of the
Interior, Bureau of Reclamation, Office of Chief Engineer, Atten-
tion: Code 400, Denver Federal Center, Denver, Colorado 80225.

a a aed

The question for each man to settle is not what he would do if he
had means, time, influence, and educational advantages, but what
he will do with the things he has.


It has been found from experience that it is mandatory that surfaces
be dry at the time of application, and that the air and concrete tem-
peratures be not less than 50° F.

Economy dictates that a relatively shallow section of sealer be used
consistent with hydrostatic pressure but in any case not less than
3/8 inch for cracks and 1/2 inch for joints. If installed properly
polysulfide sealers should last longer and provide a better seal than
rubberized asphalt mastic. Polysulfide canal sealants are available
in two types. There is a quick-set material which must be machine
applied using a costly mixer-applicator requiring experienced person-
nel and a slow-set type which can be mixed and applied by hand. The
former is more economical on large jobs and the latter is more adapt-
able to smaller ones.

Preformed Reinforced Mastic Tape

Glass cloth reinforced asphalt mastic tape has proved to be satisfac-
tory for use as a sealer for random cracks. This material is a glass
cloth reinforced rubberized asphalt mastic in tape form and has been
under test in several locations. Figure 8 below shows a glass cloth
reinforced heavy bodied asphalt mastic furnished in tape form.

The tape must be applied carefully, both tape and concrete must be
warm and dry, also the tape must be well rolled to assure proper con-
tact of the mastic to the concrete and to feather the edges of the
tape. The concrete surface must be clean before the tape is applied;
sandblasting is not always required but it is the preferred method of
cleaning. Thickness and width of the tape should be determined by
whatever is deemed desirable. On the Ainsworth Canal a 3-inch-wide
by 3/16-inch-thick tape gave the best results. This reinforced mas-
tic tape comes in various thicknesses, widths and lengths and it can
be purchased commercially.

lyethylene fil Heavy bodied
Polyethylene fi = asphalt mastic

Glass
cloth

\—90# Silicone coated kraft
paper (removed just prior
to installation).

SECTION THRU GLASS CLOTH

REINFORCED ASPHALT MASTIC TAPE
FIGURE 8


Invariably a crack will form between old and new concrete. In
removal of the old concrete it is advisable to cut it in straight
lines, thus facilitating the forming of the joint as illustrated
in Figure 3 below. This type of joint also is suggested for other
places where it is known that contraction will occur and crack con-
trol is needed.

Polysulfide sealant

B+y 4

ceRy

Paint to prevent bond, except
in groove for sealant.

CONTRACTION JOINT
FIGURE 3

It is usually good practice to remove the damaged section and replace
it with a new panel when linings heave from expansion due to temper-
ature change. In such cases an expansion joint should be included in
the repair so that there will not be a recurrence of the failure. The
type of joint shown in Figure 4 below, can be used to maintain a water-
tight lining.

Polysulfide sealant New concrete
‘ical a 1 saint

tt Sponge
rubber filler

a concrete
EXPANSION JOINT
FIGURE 4


Photograph 2. Photo PX-D-67506

The initial cost of a nickel-cadmium battery and charger is approxi-
mately the same as that of a lead acid battery and charger because
the lead acid battery must be considerably larger in capacity. It
should be noted however, when selecting a nickel-cadmium battery that
even though the maintenance is nil it is difficult to determine the
state of charge; since the amount of charge in the battery is a func-
tion of the voltage and a hydrometer is not used.

Careful consideration should be given to the proper selection of the
batteries to be used in remote area stations. If the starting bat-
tery fails the station will be off the air.

ak RRR

Emerson was profoundly right when he said that nothing great
is ever accomplished without enthusiasm. If a task is done
halfheartedly, unenthusiastically, it bears the sure stamp of
mediocrity. Enthusiasm is a quality that grows with progress.

19


REPAIR OF CONCRETE CANAL LINING 1/

Concrete is relatively brittle and has a low tensile strength. It
has a tendency to shrink during curing, expand when moisture is
absorbed, and expand and contract due to temperature changes. For
these reasons it is subject to cracking. Additional cracking may
result from frost heaving, hydrostatic back pressures, settlement
of foundation due to low density soils, piping of the foundation,
or expansion of swelling foundation soils. These characteristics
of concrete and foundation problems must be recognized in original
design as in repair. In maintenance work the cause of excessive
cracking or lining failures should be determined if possible before
the type of repair is selected.

Cracking in concrete lining is usually controlled by the use of con-
traction joints or weakened planes spaced at proper intervals so that
the cracks will occur in these joints instead of in a random pattern.
When a concrete lining is placed by hand, it is a common practice to
construct the lining in alternate panels. Since the bond between the
panels is weaker than the slab itself, this should confine most of
the cracking to the construction joints. A formed joint should be
made at the junction of slabs and filled with elastic material to
prevent the lining from leaking.

Contraction Joints

The most common type of contraction joint is a narrow groove formed
in the concrete to a depth of at least one-third of the thickness
of the lining. This forms a weakened section where cracking will
usually occur.

Transverse joints--A study of information on this subject indicates
that the transverse contraction joint spacing of 10 feet for unrein-
forced concrete lining in smaller canals is usually adequate. Spac-
ing of joints not to exceed 15 feet is satisfactory for unreinforced
lining in larger canals.

Longitudinal joints--Longitudinal joints or grooves are usually not
required in the smaller canals to control the cracking. However, in
larger canals where the side slope distance is larger than 15 feet,
it is good practice to construct grooves at a maximum 15-foot spac-
ing in the sides and invert.

1/ Much of the material in this article was adapted in part from
the Concrete Manual, Seventh Edition, and can be obtained from the
Office of Chief Engineer, Bureau of Reclamation, Building 67, Atten-
tion: Code 841, Denver Federal Center, Denver, Colorado 80225.


PORTABLE POWER CORDS FOR USE IN MAINTENANCE
AND
EMERGENCIES

In irrigation maintenance work and during emergencies rubber- and
plastic-covered power cords are often used in conjunction with port-
able powerplants to run tools and supply lighting. Experience has
shown that the selection of the correct size cable is especially
important if portable power tools are to perform efficiently with-
out overheating, or stalling and shortening tool life. For quick
reference the tables listed below are suggested guides when select-
ing the size cable needed for small tools and also for lighting.

Rubber-covered stranded cord with ground wire Type ''S" for heavy
service is recommended where it may be subject to oil and abrasion.
Because of its flexibility and ease of handling, rubber-covered
cable is often used. Type S, 0 to 600 volts for heavy duty is
recommended.

Motor Table

Single-phase (14) motors Recommended cable size

Approximate full-load Cable size @ 115 volts 1/
current amperes ~

HP - AC Amps @

motors 115 volts 100 ft cable | 200 ft cable
1/4 5.8 14 GA 2/ 14 GA
1/3 7.2 14 GA 12 GA
1/2 9.8 14 GA 10 GA
3/4 13.8 12 GA 10 GA
yl 16 12 GA 8 GA

1-1/2 20 10 GA 8 GA
2 24 | 10 GA 6 GA

NOTE: Momentary starting currents are higher than the above
values. Locked-rotor currents run between five and eight
times the full-load currents of motors.

1/ This table allows 5 percent voltage drop. Increasing con-
ductor length increases the voltage drop. The voltage drop
is subtracted from the source voltage and the difference is
the voltage available at the load. Generally a 5 percent
voltage drop can be tolerated in handtool use.

2/ It is recommended that no cord smaller than 14 GA be used.

Table 1

12


SANDBLAST GUN MODIFICATION
(Suggestion RSRG-70S-3)

For several years now the Rio Grande Project with headquarters in
El Paso, Texas, has used a fabricated sandblast gun developed by
the Bureau which does the job intended very well.1/ However, there
has been the problem of fast deterioration of pipe wyes, nozzles,
and bushings because of the abrasive action within the gun from the
sand and air. Frequent replacement of these fittings was a constant
problem.

An idea presented by Patricio V. Padilla, of the Power Field Branch,
of the Rio Grande Project, for improving the capability of the gun,
has proven to be very successful. He developed a tool to aline the
1/8-inch pipe so there is a direct feed of sand and air into the
barrel of the nozzle. This has decreased the abrasive action sub-
stantially. The cost of replacing pipe and fittings has been re-
duced approximately 75 percent.

At times when using this gun the 1/8-inch pipe, shown in the draw-
ing on the following page, is out of line and when this happens the
abrasive action on the pipe wye, bushing and nozzle begin and the
parts are soon worn out. As shown in the drawing, a 1-1/2- x 3/4-
inch pipe bushing threaded into the opposite end of a 3/4-inch to
3/8-inch bushing will permit the threading of a 3/8-inch piece of
pipe so it will extend out approximately 1-1/8 inch. It is neces-
sary to ream the 3/8-inch pipe so it will receive the 1/8-inch
inside the gun. The device must be removed after the alinement

is completed.

If further information is desired regarding this suggestion, please
write to the Project Superintendent, Bureau of Reclamation, Rio
Grande Project, El Paso, Texas 79901.

1/ See Operation and Maintenance Equipment and Procedures Release
No. 2, dated January-February 1953, or write to: Office of Chief
Engineer, Bureau of Reclamation, Denver Federal Center, Building 67,

Attention: Code 400, Denver, Colorado 80225.

14


IRRIGATION OPERATION AND MAINTENANCE
BULLETIN NO. 73

July, August, September 1970

INTRODUCTION

Starting on page 1, an article entitled "Repair of Concrete Canal
Lining," describes some of the problems that can be encountered with
concrete canal linings and the methods and materials available for
repair.

An idea for the construction of a Jack-Cart for use in servicing the
dual wheels of trucks can be found on page 10.

On page 12, an article entitled "Portable Power Cords for use in
Maintenance and Emergencies," points out the importance of the right
size power cord or cable when using power tools in conjunction with
portable powerplants.

The modification of a sandblast gun, shown on page 14, was suggested
by an employee of the Rio Grande Project, and all reports indicate
that it has been very successful in cutting parts replacement costs.

"All Purpose Maintenance Vehicle," is the title of an article on
page 16. Time consuming trips to the maintenance shop prompted
the building of a truck by the Exeter Irrigation District in
California.

Selection of the right type of battery for VHF radio repeaters is
very important in remote area stations, as pointed out in the article
to be found on page 18.

Winterizing of wet sump pumping plants and steps taken for their
protection is a question frequently asked by irrigation people.
Some thoughts on the subject from experience gained can be found
on page 20.


The Irrigation Operation and Maintenance Bulletin is published quar-
terly, for the benefit of irrigation project people. Its principal
purpose is to serve as a medium of exchanging operation and mainte-
nance information. It is hoped that the reports herein concerning
labor-saving devices and less costly equipment and procedures, devel-
oped by resourceful project people, will result in improved effi-
ciency and reduced costs of the systems for those operators adapting
these ideas to their needs.

To assure proper recognition of those individuals whose suggestions
are published in the bulletins, the suggestion number as well as the
person's name is given. All Bureau offices are reminded to notify
their Suggestions Award Committee when a suggestion is adopted.

te eRe

Division of Irrigation Operations
Office of Chief Engineer
Denver, Colorado 80225

COVER PHOTOGRAPH:
Application of rubberized
asphalt mastic in the repair
of the concrete lining on
the New York Canal, Boise
Project, Idaho, using a
heavy-duty pump. Photo
P3-D-64302



JACK-CART FOR DUAL-WHEEL
TRUCK SERVICING

(Reprinted by permission of PLOWBACK, January 1970 issue. This is
a publication of the National Park Service, National Conference of
State Parks, Washington, D.C.)

This unique and servicable shop tool can help prevent injury likely
to occur in the physical strain necessary to remove heavy dual truck
wheels. It can be constructed from scrap metal, a small hydraulic
jack, and a set of four rollers for only about $50, but it is said
to save 50 percent of the time usually required to remove the heavy
truck wheels for inspection or repair, and is a much safer method.
Mr. Clyde W. McDaniel, Maintenanceman, of the Natchez Trace Parkway
National Park Service is the designer.

To operate this device, the rear axle is raised slightly with a con-
ventional type jack, and the jack-cart is rolled under the wheels
which are to be removed. Photograph 1 below, shows how easily the
job is accomplished.

Photograph 1. Photo PX-D-67500

10


Lamp or Heater Table

Recommended cable
Load size @ 115 volts
Watts Amps 100 ft cable 200 ft cable
S00 4.4 14 GA 14 GA
750 6.5 14 GA 12 GA
1,000 8.7 14 GA 12 GA
2,000 17.4 12 GA | 8 GA
3,000 26 10 GA 6 GA
4,000 35 8 GA 6 GA
5,000 44 8 GA 4 GA
Table 2

When a combination of motors and lamps are used on one circuit add
the total amperage of the motors plus lamps to determine the cable
size to use from Table 3 below:

Cable Size for Various Currents
115 Volts With 5 Percent Voltage Drop

Amps 100 ft 200 ft 300 ft 500 ft
GA GA GA GA
5 14 14 12 10
6 14 12 12 10
7 14 12 10 8
8 14 12 10 8
9 14 10 10 8
10 14 10 8 6
12 12 10 8 6
15 12 8 8 6
20 10 8 6 4
25 10 6 | 6 4
30 10 6 | 4 2
35 8 4 4 2
40 8 4 4 | 2
45 6 4 2 1
50 6 4 2 1

i

NOTE: It is suggested that for higher loads more
than one cable be used. All lines should be fused.

Table 3

tke

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