Parker’s reliable pilot piston style P.O. check valves are designed for critical applications where safety and load holding is required and flows from 19 to 150 lpm (5 to 40 gpm) and pressures up to 420 bar (6,000 psi) are needed. These valves are available with pilot supply to either the 1st port or 3rd port depending on circuit need, and are generally used in conjunction with linear actuators across several markets within mobile or industrial hydraulics, such as aerials, material handling, and construction where durable and low leak valves are necessary to keep the machinery and operators safe.

Markets:
• Aerial
• Construction
• Material Handling
• Miscellaneous Mobile

Features/Benefits:
• Spherical poppet for low leakage
• Hardened precision ground parts for durability
• “D”-Ring design eliminates back-up rings
• Optional sealed pilot piston

Applications:
• Load holding without fine metering

Additional Technical Insight:
Pilot operated check valves, also known as P.O. checks, are used to lock a cylinder in a holding position with minimal leakage or drift. P.O. check valves that can be opened to allow flow in the reverse direction with an external signal to the pilot port. The 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, and are typically 3:1 or 4:1. A 3:1 ratio with a 3000psi load requires a 1000psi signal to the pilot port.