Single Pilot-Operated, Pilot-to-Close Check Valves

Pilot-to-close check valves operate as standard check valves, but block flow completely when a pilot signal is supplied; capable of flows up to 38 lpm (10 gpm) and pressures up to 240 bar (3,500 psi).

Parker’s durable pilot-to-close PO check valves are designed for demanding applications where precise regen functionality is required that have flows up to 38 lpm (10 gpm) and pressures up to 240 bar (3,500 psi) across several markets such as construction, material handling, and industrial manufacturing.

These valves feature an internal pilot operated piston that will help simplify hydraulic circuit or manifold design with a standard pilot ratio of 2:1 that requires half the pilot pressure than the load pressure, and ensures easy system integration with reliable performance.

Pilot operated check valves, also known as PO checks, are used to lock a cylinder in a holding position with minimal leakage or drift, and can be opened to allow flow in the reverse direction with an external signal to the pilot port.

These valves work best when used in conjunction with a control valve that vents the valve ports to tank when centered. Pilot pressure to open the checks for reverse flow is a ratio of the holding pressure, which a 2:1 is standard offering for this valve.

As an example, a 2:1 ratio with a 2,000 psi load requires only a 1,000 psi signal to the pilot port in order to shift the valve. Pilot to close checks are a normally open version of PO checks, whereby a pilot signal is required to close, not open, the check valve.