CVCV-XEN - Vented Pilot-To-Open Check Valve, T-21A

This CVCV-XEN valve is a pilot to open check valve. It has a sealed pilot, a steel seat, and is vented. It allows free flow from the valve (port 2) to the load (port 1) and blocks flow in the opposite direction. Pressure at the pilot (port 3) will open the valve from port 1 to port 2. Pilot pressure needed to open the valve is directly proportional to the load pressure at port 1. The valve is insensitive to pressure atport 2 because the spring chamber is referenced to the vent (port 4).

Technical Features

• Pilot pressure as low as 75 psi (5 bar) higher than the pressure at the vent can prevent the valve from closing.


• Provides hose break protection, prevents loads from drifting and positively locks pressurized loads.


• Will accept pressure at port 4 (vent) but can not exceed 5000 psi (350 bar).


• Extremely low leakage. The seat and poppet are heat treated for long life. If the load drifts due to the valve, the seat has probably been damaged by contamination and the valve should be replaced.


• Pilot-to-open check cartridges are locking valves, not motion control valves. For motion control applications, use counterbalance valves.


• Sealed pilot for use in circuits where cross port leakage is undesirable.


• Four-port pilot-to-open check cartridges and four-port counterbalance cartridges are physically interchangeable (i.e. same cavities, same flow path for a given frame size). However, cartridge extension dimensions from the mounting surface may vary.


• Port 4 (vent) should never be blocked as seal weepage will eventually cause valve to malfunction.


• Approximately 1 drop (0,07 cc) of fluid will pass from the pilot area to the vented spring chamber every 4000 cycles.


• Incorporates the Sun floating style construction to minimize the possibility of internal parts binding due to excessive installation torque and/or cavity/cartridge machining variations.