PAD 1S7977 - Caterpillar

Location and Function
Illustration 1 g00936127
(1) Charge pumpCharge pump (1) is located on the upper pump stack.The upper and lower piston pumps for the drag conveyors share the same charge pump.The charge pump performs the following functions:
Replaces oil lost through lubrication of the internal components
Replaces oil lost through internal leakage.
Replaces oil that is sent to the hydraulic oil cooler.
Provides charge oil for the upper and lower pump stacksNote: Correct charge pressure must be maintained under all conditions of operation in order to maintain the performance of the pump controls.Operation and Oil Flow
Illustration 2 g00936140
(1) Charge pump (2) Line to upper pump stack (3) Line from hydraulic tank (4) Charge filter (5) Line to cooler bypass manifold (6) Line to lower pump stack (AA) Charge pressure (AB) Sump (AC) Activated componentsCharge pump (1) draws oil from the hydraulic oil tank. Oil is drawn through a suction screen that is in the tank. The charge pressure oil is sent to charge filter (4). Charge pressure oil will then go to the upper pump stack and the lower pump stack. If the filter is plugged, the internal relief valve in the charge filter will direct oil to the oil cooler bypass manifold. The charge pump is a gear pump that produces a flow of 23 cc (1.4 in3) for each revolution of the pump.