CHAPTER 4. REPAIR OF CENTRIFUGAL PUMP

REPAIR OF CENTRIFUGAL PUMP

are in constant contact to stop seepage of fluid through

4-1. Description

the seal. Both parts are sealed to their associated parts

This self-priming centrifugal pump is designed to

with petroleum-resistant Buna N rubber parts.

pump flammable liquids at relatively high discharge

heads. It uses a closed-type impeller which is mounted

4-2. Pump Fits, Tolerances and Wear Limits

directly on the extended engine crankshaft. It contains

no bearings since the crankshaft is adequately sup-

Table 4-1 lists pump fits, tolerances, and wear limits.

ported by the engine bearings. A face seal prevents

Refer to the table to help you determine if parts

leakage around the shaft. The seal consists of a Ni-

replacement is required or if continued serviceability

Resist stationary member and a spring-loaded carbon

of the parts is possible.

rotating member. The highly finished mating surfaces

Table 4-1. Pump Fits, Tolerances, and Wear Limits

Normal clearances

Maximum allowable

(in inches)

Component points of

Maximum

clearance

Minimum

measurement

0.052

0.092

0.042

Impeller-to-wear ring clearance

5.107

Wear ring internal diameter

5.015

Impeller external diameter at wear ring surface

4-3. Pump Repair

for instructions. Disassemble the centrifugal pump as

a. Removal and Disassembly. Remove the suction

piping assembly, discharge piping assembly, and the

instrument control panel. Refer to TM 5-4320-272-12

4-1