3 - 11
Introduction to Hydraulic Schematic
Symbols (cont'd)
Control Valves
Section E
9803/3280
Section E
3 - 11
Issue 1
Basic System Operation
A189700
A189690
Used to enclose several
valves indicating that they
are supplied as one unit
3-Position, 4-Port
spring centred pilot
operated valve
3-Position, 6-Port
spring centred hand
operated valve
3-Position, 4-Port
spring centred solenoid &
pilot pressure operated valve
3-Position, 4-Port
spring centred detent
hand operated valve
Non - return valve
Non - return valve with
back pressure spring
Pilot operated
non - return valve
One way restrictor
High pressure selector
(shuttle valve)
Throttling orifice -
normally closed
Throttling orifice -
normally open
Relief valve
Variable restrictor