Komatsu Utility PC12R-8 MISTRAL, Shop Manual

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2.BASIC PRINCIPLE
1) Flow control of unload valve
. The unload valve maintains LS differential pressure D P
LS
which is differential pressure between the pump di-
scharge pressure P
P
and the LS pressure P
LS
at the outlet port of control valve (actuator load pressure) at a con-
stant level. ( LS differential pressure D P
LS
=Pump discharge pressure P
P
± LS pressure P
LS ).
. If the LS differential pressure D P
LS
becomes lower than the setting pressure, the Unload valve reduces drain
flow to the circuit, and if it becomes higher, the Unload valve increases drain flow.
H For the details of this action, refer to the descriptions of Unload valve.
10-45
PC12R-8 PC15R-8
RKP00601
Actuator
Control valve
Pump discharge
Unload valve
P
P
P
LS
T