Page 151 - ParkerQuickCouplingCatalog38002010

Quick Coupling Division
8145 Lewis Road • Minneapolis, MN 55427
www.parker.com/quickcouplings E-4
Check Valves
E
Valves
Technical Information
Features
Parker’s Check Valves employ several unique features
that insure years of trouble-free operation. Specific features
for each series of check valves are listed within this section.
Crack Pressure
Crack pressurerefers 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.
The graphic symbol for a check-valve is:
TYPICAL HYDRAULIC CIRCUIT. THE CHECK VALVE IS USED TO
PROTECT THE PUMP BY PREVENTING PRESSURE FROM RETURN-
ING TO THE OUTLET PORT OF THE PUMP.
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.
CYLINDER
CONTROL
VALVE
TANK
PUMP
CHECK
VALVE
TANK
RELIEF
VALVE
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
Crack
Rated Pressure
Body Size Material Pressure Range
CV Series 1/4 - 1" Steel 3000 PSI 5-130 PSI
DT Series 1/4 - 1 1/4" Steel 5000 PSI 5-200 PSI
DC Series 1/4 - 2” Steel up to 5000 PSI 5-100 PSI
Applications
Selection Guide