Pvbs, Main Spools With Pressure Compensated Control; Pressure Compensated System Characteristics; Typical Applications For Pressure Compensated Systems - Danfoss PVG 16 Service Manual

Service Manual
PVG 16 and 32 Service Assembly/Disassembly Guide
General information

PVBS, main spools with pressure compensated control

© Danfoss | November 2017
The PC control maintains constant system pressure in the hydraulic circuit by varying the output flow of
the pump. Used with a closed center control valve, the pump remains in high pressure standby mode at
the PC setting with zero flow until the function is actuated.
Typical operating curve
Q max
0
0 Pressur e
Once the closed center valve is opened, the PC control senses the immediate drop in system pressure
and increases pump flow by increasing the swashplate angle.
The pump continues to increase flow until system pressure reaches the PC setting.
If system pressure exceeds the PC setting, the PC control reduces the swashplate angle to maintain
system pressure by reducing flow. The PC control continues to monitor system pressure and changes
swashplate angle to match the output flow with the work function pressure requirements.
If the demand for flow exceeds the capacity of the pump, the PC control directs the pump to maximum
displacement. In this condition, actual system pressure depends on the actuator load.
For additional system protection, install a relief valve in the pump outlet line.

Pressure compensated system characteristics

•
Constant pressure and variable flow
•
High pressure standby mode when flow is not needed
•
System flow adjusts to meet system requirements
•
Single pump can provide flow to multiple work functions
•
Quick response to system flow and pressure requirements

Typical applications for pressure compensated systems

•
Constant force cylinders (bailers, compactors, refuse trucks)
•
On/off fan drives
•
Drill rigs
•
Sweepers
•
Trenchers
Simple closed center circuit
P101 166E
P101 965
L1104530 | AX00000133en-US0106 | 9