Figure 4B-3. Pressure Feed to Vanes
The pressure plate seals the pump chamber as shown in
Figure 4B-4. System pressure is effective against the area at
the back of the plate, which is larger than the area exposed
to the pumping cartridge. Thus, an unbalanced force holds
the plate against the cartridge, sealing the cartridge and
providing the proper running clearance for the rotor and
vanes. The pressure plate also contains passages for feeding
pressure to the space between the vanes and inserts.
To remove a pump from the pump drive, proceed as fol-
1. Turn the suction line valve to the closed position.
2. Disconnect the suction and outlet Iines from the pump.
Cap the lines and plug the pump ports to prevent the entry
of foreign material into the pump or hydraulic system.
3. Block the pump in position against the pump drive so
that it will not drop when the capscrews are removed. Re-
COVER END STRAIGHT VANE
move the two capscrews securing the pump to the pump
PUMPING CARTRIDGE SHOWN
drive. Slide the pump back from the pump drive until the
driveshaft is clear of the pump drive, and remove the pump
Figure 4B-4 Pressure Plate Functions
to a suitable repair area.