Pressure Tank Valve

(5) Aline and connect the plug assembly (14) to the

inches long. Cut a 24-inch length of 1-inch pipe to use

quick-disconnect coupling half (5).

as a handle. Weld the handle, the bar stock, and the

(6) Test to see that the plug is engaged and locked

steel block together.

in the quick-disconnect coupling half. If the knurled ring

(2) Holding device. Select a piece of steel 1/8 by 6

on the quick-disconnect coupling half is connected

by 25 inches (fig. 3-1). From it into a 6-inch diameter

properly, it should not slide freely.

circle starting from the center (12 1/2 in.). When the

(7) Close the hinged clamp around the pressure

circle is completed, bend the two ends approximately 3

tank aid fasten the attached wingnut.

inches out from the circle. Make up two pieces of steel

(8) Fasten the valve shaft (6) to the stud on the

each 3/8 by 3 by 4 1/2 inches and four pieces of steel

agent tank with the clamp (10, eyelet (7), and wingnut

each 3/8 by 1 1/2 by 3 5/8 inches. Along the four pieces

(11).

of steel that have a length of 3 5/8 inches, taper the 1

1/2-inch surface to butt against the outside contour of the

6-inch circle. Weld one piece of steel 3/8 by 3 by 4 1/2

3-3. Pressure Tank Valve

inches and two pieces of steel 3/8 by 1 1/2 by 3 5/8

inches to each end projecting from the circle. Drill four

General support maintenance personnel are authorized

holes threaded 3/8-16NC in the four 3/8 by 1 1/2 by 3

to replace the pressure tank valve.

5/8-inch steel pieces positioned to suit the vise. Install

four screws. Drill 17 holes, which will be used for rivets,

a. Inspection. Check the pressure tank valve for the

in the 1/8 by 6 by 25- inch piece of steel at locations

following identification:

similar to those shown in figure 3-1. Prepare a piece of

leather 5/16 by 6 by 18 inches and rivet it in place in-

(1) The letter D must be stamped on the spool (15,

side the steel circle using approximately 17 countersunk

fig. 2-5) in six places, and 1175-200D must be stamped

rivets and washers as shown in figure 3-1. The holding

on the valve body (16). If the letter D appears on the

device has a spread of about 3/4 inch when free and a

spool and valve body, it is the authorized type of valve.

spread of about 1/2 inch when compressed.1

(2) If the spool and valve body are not identified

properly ((1) above), they must be modified. Modify

c. Removal.

valves according to MWO 3- 1040-204-45/1, 31 July

1970.

(1) Perform the operations in 2-3a(1) through (8).

(3) Check the operation of the pressure tank valve

(2) Disconnect the coupling nut (12, fig. 2-5) from

(17) by turning the valve handle (9) clockwise and

the pressure tank valve (17) and re- move the valve shaft

counterclockwise. The valve should operate with ease.

(6).

Replace the valve if it is difficult to operate.

(3) Secure the pressure tank in the holding device

(fig. 3-1). Place the parts in a vise shown in figure 3-2.

b. Manufacture. To prevent damage to the pressure

(4) Remove the plug assembly (14, fig. 2-5) and

tank, a locally fabricated valve wrench and holding

dust cap (13).

device is recommended.

(5) Remove the check valve assembly (18) and the

dust cap (19).

(1) Valve wrench. Select a block of steel 1 1/4 by

(6) With the wrench (fig. 3-2) remove the pressure

3 1/4 by 4 1/4 inches (fig. 3-1). Along the 3 1/4-inch

tank valve from the pressure tank. The use of a propane

surface, measure 1 1/16 inches in from one end and

torch or blow torch on the neck of the pressure tank will

mark the surface. Measure 1 1/16 inches in from the

make it easier to re- move the pressure tank valve.

other end and mark that surface also. Along the 4 1/4-

inch surface, measure a depth of 1 3/4 inches in from the

d. Assembly.

two 1 1/16-inch-marked places. Cut out the 1 3/4- inch

piece from the steel block. Measure 3 inches along the

NOTE

two sides of the 4 1/4-inch surface and mark the

surfaces. Measure 1 inch in toward the center of the

block from both ends along the uncut 3 1/4-inch surface

Use antiseize compound or tape on

and mark the surfaces. Cut off the excess steel in the

pipe threads before assembly.

angles between the 3-inch marks and the 1-inch marks.

Drill a hole in the steel block for a depth of about 1/2 inch

(1) Screw the pressure tank valve into the opening

to suit the inside diameter of a 1-inch pipe. Select a solid

of the pressure tank and tighten with the wrench (fig. 3-

round of steel of the diameter to fit the hole and cut a

2).

piece 3

3-3