VALVE AS-CHECK 2639098 - Caterpillar

Illustration 1 g01469127
(1) Accumulator (2) Pilot oil manifoldAccumulator (1) stores pilot pressure oil for use at the main control valves. During some operations, the pilot system needs more oil because there is insufficient flow from the pilot pump. Accumulator (1) 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 operations
Illustration 2 g01469249
Accumulator (1) Accumulator (2) Pilot oil manifold (3) Gas chamber (4) Bladder (5) Bowl (6) Oil chamber (7) Inlet manifold (8) Port (9) Check valve (10) PassagePilot oil flows through the pilot filter and through port (8) of pilot oil manifold (2) . The pilot oil opens check valve (9) and flows through passage (10) to the hydraulic activation control valve. Pilot oil then flows to the pilot control valves.Accumulator (1) provides oil to the pilot line as makeup oil. During combined operations, the pilot system needs more oil because there is not enough flow from the pilot pump. When implements are lowered with the engine stopped, makeup oil supply is provided by accumulator (1) .Accumulator (1) stores hydraulic pressure oil by taking advantage of the compressibility of nitrogen gas in gas chamber (3) .The pilot pump oil in port (8) opens check valve (9) and flows into oil chamber (6) through inlet port (7) . The pilot oil pressure acts against bladder (4) and the nitrogen gas in chamber (3) is compressed.Check valve (9) is located in the passage that is connected to inlet port (8) . Check valve (9) prevents oil from flowing back to port (6) . Oil from accumulator (1) flows through passage (10) . This oil is used to shift the main control valve stems.