MANIFOLD 1426240 - Caterpillar

Constant Flow
Illustration 4 g01022658
Steering and Implement Pump (Constant Flow) (1) Piston Pump (2) Compensator Valve (3) Piston and Barrel Assembly (4) Shaft (5) Bias Spring (6) Swashplate (7) Actuator Piston (8) Load Sensing Signal Pressure (9) Pump Outlet (10) Margin Spring (11) Margin Spool (12) Pump Inlet (13) Adjustment Screw (14) Pressure Cutoff Spool (15) Orifices (16) Passage to Actuator Piston (17) Line To the Control Valve Group (18) Orifice (19) PassageAs the pump increases flow or decreases flow in order to match the change in the flow requirements, the forces above the flow compensator spool and below the flow compensator spool will equalize.The following pressures will act on the top end of flow compensator spool (11) :
Margin spring (10)
Load sensing signal pressure (8) The following pressure will act on the bottom end of flow compensator spool (11) :
Supply pressure from pump outlet (9) Once the pressures become equal on each end of the spool, flow compensator spool (11) will meter oil to actuator piston (7). Bias spring (5) will be compressed and the system will stabilize.Swashplate (6) is held at a relative constant angle in order to maintain the required flow.Destroke
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Steering and Implement Pump (Destroke) (1) Piston Pump (2) Compensator Valve (3) Piston and Barrel Assembly (4) Shaft (5) Bias Spring (6) Swashplate (7) Actuator Piston (8) Load Sensing Signal Pressure (9) Pump Outlet (10) Margin Spring (11) Margin Spool (12) Pump Inlet (13) Adjustment Screw (14) Pressure Cutoff Spool (15) Orifices (16) Passage to Actuator Piston (17) Line To the Control Valve Group (18) Orifice (19) PassageWhen less flow is required, piston pump (1) destrokes. The piston pump destrokes when the supply pressure from pump outlet (9) becomes greater than the combined pressure of load sensing signal pressure (8) and margin spring (10) .Flow compensator spool (11) is raised. This allows more oil flow to actuator piston (7). Pressure on actuator piston (7) is now increased.The increased pressure overcomes the force of bias spring (5) which moves swashplate (6) to a reduced angle. When the supply pressure at pump outlet (9) matches the combined pressure of load sensing signal pressure (8) and margin spring (10), the flow compensator spool returns to a metering position. Piston pump (1) will return to a constant flow.The following conditions result in destroking the pump:
When a main control spool for a hydraulic control valve is moved to the HOLD position the hydraulic pump will destroke.
If the main control spool for a hydraulic control valve is moved to a position that requires less flow, the hydraulic pump will destroke.
If multiple hydraulic control valves are being used, the hydraulic pump will destroke when there is a reduction in flow demand from any one of the hydraulic control valves.
If the engine speed increases, the piston pump destrokes. When the piston pump destrokes, supply oil pressure from pump outlet (9) decreases on the bottom side of flow compensator spool (11) .The force on the top of flow compensator spool