PIN 7V9799 - Caterpillar

Illustration 2 g00476750
Pipelayer hydraulic system (1) Lubrication outlet port (2) Lubrication inlet port (3) Winch for the boom (4) Winch motor for the boom (5) Lubrication outlet port (6) Lubrication inlet port (7) BOOM RAISE port (8) BOOM LOWER port (9) Brake release port (10) Return manifold (11) Lubrication inlet port (12) QUICK-DROP port (13) Lubrication outlet port (14) Hook winch (15) Lubrication outlet port (16) Hook winch motor (17) Combination valve (18) Brake release port (19) Lubrication inlet port (20) Port for winch speed (21) Drain port (22) Brake release port (23) HOOK LOWER port (24) HOOK RAISE port (25) LOWER motor port (26) RAISE motor port (27) Speed control valve (hook winch motor) (28) Hook pilot control valve (29) Boom pilot control valve (30) Counterweight cylinder (31) Counterweight control valve (32) Boom kickout valve (33) Auxiliary hydraulic pump (34) Main hydraulic pump (35) Oil cooler (36) Accumulator (37) Distribution manifold (38) Load sensing manifold (39) LOWER motor port (40) RAISE motor port (41) Brake release port (42) Hook control valve (43) Boom control valve (44) Manifold (45) Shutoff valve (AA) Pump pressure (PP) Pilot pressure (LL) Return oilThe hydraulic system consists of the following major components: winch (3) for the boom, winch motor (4), hook winch (14), hook winch motor (16), combination valve (17), counterweight cylinder (30), counterweight control valve (31), boom kickout valve (32), auxiliary hydraulic pump (33), main hydraulic pump (34), oil cooler (35), accumulator (36), load sensing manifold (38), hook control valve (42), boom control valve (43) and manifold (44) Operating Principles
The hydraulic system is a continuous flow system that permits a minimum flow in the system when hook control valve (42) , boom control valve (43) and counterweight control valve (31) are not activated. Main hydraulic pump (34) and auxiliary hydraulic pump (33) work together to supply oil pressure to the hydraulic components.Counterweight Circuit
Auxiliary hydraulic pump (33) supplies oil for the counterweight hydraulic circuit and lubrication for the winches. When counterweight control valve (31) is operated, the oil goes to counterweight cylinder (30) . The return oil from the cylinder exits valve (31) and the oil goes to oil cooler (35) in order to lower the oil temperature. When counterweight control valve (31) is in the HOLD position, the oil supply to valve (31) passes through the valve and the oil goes directly to oil cooler (35) . The oil passes through oil cooler (34) to distribution manifold (37) for lubrication of the winches.Note: If oil cooler (35) ever becomes frozen or plugged, a bypass in counterweight control valve (31) reroutes the oil directly to distribution manifold (37) .Pilot Circuit
Main hydraulic pump (34) supplies oil for the boom and hook control valves and the pilot circuit. The oil from pump (34) travels to manifold (44) . A portion of the oil travels through manifold (44) to the pilot circuit. Accumulator (36) is charged with