COJA-XEN - Pilot-To-Close Check Valve, T-19A

This valve is a spring biased closed, pilot-to-close check cartridge that has a 1.8:1 pilot ratio. The valve allows flow from port 1 to port 2 and blocks reverse flow. Pressure at the pilot port opposes pressure at port 1 at a ratio of 1.8:1. This valve is most often used in regeneration circuits.

Technical Features

• Nominal pilot ratio is 1.8:1. This means that a pressure of 1000 psi (70 bar) at the pilot port will close a valve against a pressure of 1800 psi (125 bar) at port 1. Any decay or loss of pilot pressure could allow the valve to open, even if it is a momentary decay or loss.


• Pressure at the port 2 area directly opposes pilot pressure.


• Reverse flow through the valve from port 2 to port 1 is not possible under any condition.


• With equal pressures at all ports the valve is closed.


• In the begining the CO*A’s did not have a positive seal on the pilot pistons and the CO*B’s did. Now the CO*A’s are positively sealed and the 2 valves are mechanically identical. CO*A’s are more readily available and cost less.


• Stainless steel cartridge options P or W are intended for use within corrosive environments with all external components manufactured in stainless steel or titanium. Internal working components remain the same as the standard valves.


• 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.