SPIDER AS-FAN 5575603 - Caterpillar

Illustration 1 g00419022
Pilot oil manifold (partial view) (3) Accumulator (4) Pilot relief valve (9) Pilot oil manifold (13) Gas chamber (14) Bladder (15) Bowl (16) Oil chamber (17) Passage (18) Check valve (19) Inlet port (20) Passage (21) ValvePilot oil flows through the pilot filter and through passage (20) of pilot oil manifold (9). The pilot oil opens check valve (18) and flows through passage (17) to hydraulic activation control valve (8). Pilot oil then flows to the pilot control valves.Accumulator (3) 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 the accumulator.The accumulator stores hydraulic pressure oil by taking advantage of the compressibility of nitrogen gas in gas chamber (13) .The pilot pump oil from passage (20) flows through inlet port (19) and into oil chamber (16). The pilot oil pressure acts against bladder (14) and the nitrogen gas in chamber (13) is compressed.Check valve (18) is located in the passage that is connected to inlet port (19). The check valve prevents oil from flowing back to passage (20). Oil from accumulator (3) flows through passage (17). This oil is used to shift the main control valve stems.