Rotary-Displacement Pumps

MIL-HDBK-1164

d)

Check the pump and motor alignment after reassembly.

6.5.2

Rotary-Displacement Pumps. There are numerous types of rotary

displacement pumps and, therefore, it is not possible to set up detailed maintenance

procedures that apply to all types. Establish individual maintenance procedures

according to the manufacturer's manual. Using the manual, set up procedures similar

to those presented for a centrifugal-type pump. At annual intervals, disassemble the

pumps and clean both exterior and interior surfaces.

6.5.2.1

Clearances. Check clearances for tolerances listed in the manufacturer's

manual.

6.5.2.2

Packing. Check the packing assembly, and repack as needed.

6.5.2.3

Bearings and Alignment. Check the bearings and the alignment of the

pump and motor.

6.5.2.4

Checklist Items. Check all items included in the checklist previously

determined from the manufacturer's manual and the listings for centrifugal-type pumps.

6.5.2.5

Painting. Paint exterior surfaces and interior surfaces subject to rust with

a suitable underwater paint or effective protective coating.

6.5.3

Reciprocating-Displacement Pumps. There are three types of

reciprocating pumps: plunger, piston, and diaphragm. Consult the manufacturer's

manual for each individual pump.

6.5.3.1

Calculations. Calculate the delivery of piston and plunger pumps every

year. The decrease in percent delivery from the volumetric displacement per pump

stroke is termed "slippage." Excessive slippages indicate the need for maintenance

and possible repair.

a)

Volumetric Displacement. Compute the volumetric displacement

by multiplying the piston or plunger area by the length of stroke. Make proper

allowance for double-action pumps.

b)

Delivery. Calculate the percent delivery from a comparison of the

measured delivery per stroke and the computed volumetric displacement per stroke. If

delivery is less than 90 percent of the volumetric displacement, check the valves,

pistons, and packing for leakage. Make any necessary replacements to maintain the

desired efficiency.

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