Section VII. MAINTENANCE OF DIAPHRAGM AND PLUNGER ASSEMBLY

KEY to fig. 4-3:

b. Clean all remaining parts with an approved

19.

Suction nipple

1. Discharge nipple

cleaning solvent; dry thoroughly.

20.

Accumulator cap

2. Nut

c. Inspect the suction and discharge valve flaps

21.

Gasket

3. Washer

for cracks, deterioration, brittleness, and other

22.

Nut

4. Discharge elbow

23.

Flat washer

imperfections which could result in valve leakage.

5. Gasket

24.

Accumulator

6. Screw

Replace damaged valve flaps.

25.

FILL HERE TO PRIME label

7. Check valve seat

d. Inspect the check valve seats for cracks,

26.

SUCTION label

8. Screw

distortion, and damage to the valve seating area.

27.

Gasket

9. Lock washer

Remove small nicks with a fine file or stone.

28.

Cap screw

10. Valve weight

29.

Lock washer

Replace a damaged seat.

11. Valve weight

30.

Check valve seat

12. Valve flap

e. Inspect the accumulator for cracks, distortion,

31.

Machine screw

13. Stud

dam aged threads, and damaged gasket surfaces;

32.

Lock washer

14. Nut

replace a damaged accumulator.

33.

Valve weight

15. Flat washer

f. Inspect all other parts for cracks, distortion,

34.

Valve weight

16. Discharge flange

35.

Valve flap

17. Gasket

and damaged threads; replace damaged parts.

18. Stud

36.

Stud

4-16. Reassembly

b. Disassemble the accumulator and suction

a. Reassemble the accumulator and suction

assembly as shown in figure 4-3, items 19 through

35.

c. Do not remove the studs (36) from the

Note. Take care when assembling the discharge and

diaphragm pot unless they are damaged and

suction assemblies. Make sure the valve flaps (12 and 35) are

centered on the valve seats (7 and 30 ) and that the flaps are

require replacement.

free from distortion and puckering when the related parts are

4-15. Cleaning and Inspection

assembled and secured into place.

b. Reassemble the discharge assembly as shown

a. Clean the rubber parts by wiping with a clean

in figure 4-3, items 1 through 17.

dry cloth.

Section VII. MAINTENANCE OF DIAPHRAGM AND PLUNGER ASSEMBLY

4-17. Description

housing and bearing assembly mounted at the top

of the plunger assembly is also mounted on the end

a. The diaphragm is a tough, flexible rubber ring

of the crankshaft so that it rotates with the shaft.

which is mounted between the diaphragm pot and

This imparts an up-and-down reciprocating motion

the diaphragm ring which is secured to the frame.

to the plunger assembly. On the upward stroke, the

The center of the diaphragm is secured to the

plunger rod pulls the upper diaphragm plate and

plunger assembly which forces the center of the

the diaphragm up. On the downward stroke, the

diaphragm into and out of the diaphragm pot. On

heavy plunger spring pushes the diaphragm plate

the upward stroke, a partial vacuum is created

downward. By spring-loading the downward

between the diaphragm and the pot. This sucks

stroke, damage to the pump will be minimized if

water through the suction valve and into the pot.

rocks or other debris is pulled into the pump during

On the downward stroke, the suction valve closes

operation.

and the water in the pot is forced out through the

discharge valve. In this manner water is trans-

4-18. Disassembly

ferred, under pressure, from the suction to the

a. Remove the suction and discharge assembly

discharge side of the pump to cause the required

(para 4-14).

pumping action.

b. Disassemble the diaphragm and plunger

b. The plunger assembly is powered by the

assembly following the sequence shown in figure 4-

crankshaft of the pump gear case. The bearing

4-9