CHAPTER 6. PUMPING ASSEMBLY REPAIR INSTRUCTIONS

CHAPTER 6

PUMPING ASSEMBLY REPAIR INSTRUCTIONS

Section I. GENERAL

Two flexible tapered grids, set in grooves in each coupling

6-1. Description

half, connect the engine and pump. The two outer cover

This section covers the components of the pump

halves are connected by eight bolts and nuts. The first

assembly.

Refer to Chapter 7 for engine repair

and second stage impellers of the rotating element

instructions. The two-stage centrifugal pump has an

assembly increase the pressure and maintain the flow of

upper case and bottom case of cast iron that serves as a

petroleum through the pump.

cover and mounting for the rotating element assembly.

The bottom case is mounted on the skid assembly and

The low-and high-pressure switches are mounted on the

has 2 suction flanges on the left side and 2 discharge

instrument panel box.

Both switches automatically

flanges on the right side. Within the upper and bottom

protect the pump from possible damage of abnormal

cases are chambers to direct the flow and maintain the

operating pressures. If the pump discharge pressure falls

pressure of petroleum through the pump. The engine

below, or rises above the preset ranges of the pressure

drives the rotating element assembly by a coupling. The

switches, an electrical circuit is closed in the affected

engine coupling is keyed to the accessory drive shaft.

pressure switch. This activates the carburetor solenoid

The pump coupling is keyed to the pump shaft.

which reduces engine rpm to idling speed.

Section II. PUMP ASSEMBLY COMPONENTS

62. High and Low Pressure Switches

b. Clean and inspect.

a. Remove and install the high and lowpressure

c. Adjust the low pressure switch as follows.

switches (fig. 6-1) located on the side of the instrument

control panel as follows:

(1) Tag and remove the leads from the switch

terminals.

(1) Place the safety switch located on the

instrument panel in the "off" position. This will disconnect

(2) Disconnect the tubing from the switch

voltage from the pressure switches.

pressure connection and connect the switch to a source of

pressure that can be varied between zero (0) and 150 psi.

(2) Remove the pressure switch cover and

disconnect the two leads from the switch.

(3) Connect a test lamp circuit between the

common and normally closed terminals on the switch.

(3) Disconnect the copper tubing from the

The lamp should light.

switch bellows housing and remove the nut from the

nipple containing the switch leads.

(4) To adjust the switch for series operation of

the pump, slowly raise the pressure on the switch to 110-

(4) Remove the screws, nuts, and washers

120 psi. The lamp should go out. If the lamp goes out

holding the switch housing to the control panel and

before reaching 110 psi, turn the adjustment nut (fig. 6-1)

remove the switch.

(5) Install in reverse order.

6-1