New Holland CX720 Repair Manual page 57

DISTRIBUTION SYSTEMS - PRIMARY HYDRAULIC POWER SYSTEM
High Pressure Circuit Low Demand
1 Straw elevator stack valve
3 Pressure Compensating Valve
5 Swash Plate
When output from the pump is meeting the demand of the hydraulic circuit the output pressure of the hydraulic pump
in gallery (E), will continue to rise unless the flow from the pump is controlled.
As pump pressure increases the differential between system pressure (E), and load sensed pressure (B), will similarly
increase. When this differential rises towards 21 bar (305 psi) the pressure in gallery (E), causes the flow compen-
sator spool to move back against the spring and load sense pressure in Gallery (B), to open gallery (E), to gallery
(D). The controlled pressure rise in gallery (D), operates the swash plate servo piston and changes the swash plate
angle to reduce pump output according to demand.
It can now be seen that whenever the differential pressure between system and load sensed pressures approaches
21 - 24 bar (305 - 348 psi) the flow compensator valve will operate to control the angle of the swash plate and
consequently pump flow (output).
The load sensing shuttle valves will always allow the service requiring the highest pressure to pass that pressure onto
the flow compensating valve.
High Pressure Circuit Low Demand
Standby Pressure @ 190
bar (2755 psi)
Control Pressure
5
BSC1301C
2 Main frame stack valve
4 Flow Compensating Valve
6 Return oil from hydrostatic motors
2 4/7/2006
A.10.A / 37
Return to Reservoir
Charge Pressure