E-3
Parker Hannifin Corporation
Quick Coupling Division
Minneapolis, MN
www.parker.com/quickcouplings
E
Valves
Outlet Port
Poppet
Seat
Pressure at outlet port.
Poppet is against seat.
Flow is blocked at seat.
Poppet
Seat
Inlet Port
Outlet Port
Pressure at inlet port.
Poppet is moved off seat.
Flow is allowed through valve.
Inlet Port
Check Valves
Technical Information
Parker’s Check Valves have several unique features that insure
years of trouble-free operation.
CYLINDER
control
valve
TANK
pump
check
valve
TANK
RELIEF
valve
The graphic symbol for a check-valve is:
Crack Pressure
Crack pressure refers to the amount of fluid pressure in the
free flow direction required to move the poppet off the seat.
The normal crack pressure setting is 5 PSI; however, other
crack pressures are available to allow the check valve to
perform special circuit functions, or operate under unique
conditions.
Check valves are not field repairable or adjustable.
Crack pressure settings are made at the factory only.
Applications
Typical hydralic circuit, the check valve is used to protect the
pump by preventing pressure from returning to the outlet
port of the pump.
Selection Guide
Series Body Size Material Type
Rated
Pressure
(
psi)
Crack
Pressure
Range
(
psi)
CV Series 1/4 - 1”
Steel
Metal
to
Metal
Seal
3000
5-130
DT Series 1/4 - 1 1/4”
2500-5000 5-200
DC Series 1/4 - 2”
3000
5-100
CPIFF
Series 1/4 - 1” Steel
Soft
Seat
5000
5-65
3
C Series 1 1/4 - 2” Steel
3000
5-65
S6C
Series 1/4 - 1”
316
Stainless
Steel
6000
5-65
Oil cooler bypass circuit. If return line pressure becomes
excessive due to resistance through oil cooler (such as startup
in cold weather). Check valve opens and allows oil to bypass
the cooler and flow to the tank.