PUMP GP-GEAR 3180691 - Caterpillar

Illustration 1 g00858045
(3) Accumulator (5) Line (17) Inlet
Illustration 2 g00574614
Accumulator (3) Accumulator (5) Line (17) Inlet (18) Oil chamber (19) Vessel (20) Bladder (21) Gas chamber (22) Check valve (23) Pilot manifoldThe accumulator stores pilot pressure oil for use at the swing control valve and the main control valves. During some operations, the pilot system needs more oil because there is insufficient flow from the pilot pump. Accumulator (3) will provide pilot pressure oil to the pilot system when the pilot pump flow is inadequate. Insufficient supply of pilot oil flow to the pilot system may be caused by the following two reasons:
Implements are lowered while the engine is stopped and oil supply to the main control valves is stopped.
Combined operationsIn the accumulator, gas chamber (21) is surrounded by bladder (20). The gas chamber is filled with nitrogen gas. Pilot oil in line (5) enters pressure oil chamber (18) from inlet port (17). The pilot oil acts against bladder (20) and the nitrogen gas in gas chamber (21) is compressed. Check valve (22) prevents a backflow of the stored oil in the accumulator. The stored oil is used only for operating the stem of the control valve.