The Prince RD-1800 Valve is a direct acting ball/spring type pressure relief. The valve is compact and simple in design. This type relief is fast opening and is well suited for pressure spike protection. The performance curves below indicate the low cracking pressure typical to ball/spring reliefs. The valve has a standard steel seat, externally adjustable.

The Prince valve model RV is a differential poppet type inlet relief.  The valve is made up of a relief cartridge and a cast iron valve body.  The differential poppet type relief provides smooth quiet performance with a minimum variation between cracking and full flow pressures.  This type relief is also less sensitive to system contamination.  The model RV is well suited as a system relief up to 30 GPM and 3000 PSI.  It is available in two pressure ranges and both an externally adjustable and shim adjustable version.

The Prince valve model DRV is a differential poppet type double relief.  This valve uses the same relief cartridge as the model RV.  The double relief is used in systems that require cross-over relief protection such as a reversible hydraulic motor, or systems that require a cushion valve such as double acting cylinders.

DXV Cushion Valves are designed to eliminate or minimize shock, surge and overload conditions on hydraulic equipment. They may be used with cylinders of equal displacement or with motors, to provide crossover relief up stoppage. Under standard conditions, when a control valve is in neutral or closed position, the excess pressure created by overload, shock or stress has no possibility of relief through the primary relief valve. A Cushion Valve located between the control valve and the actuator minimizes or eliminates this condition. In a motor application, the need for an anti-cavitation check may be eliminated, since relieved oil is directed into the opposite side of the Cushion Valve. Model DXV, with ball/spring relief valves, has hardened seats for long, trouble-free service. It is available with a PSI check spring which will allow the cushion valve to act as a relief in one direction and permits free-flow at 5 PSI in the opposite direction.

These Relief Valves have been designed to give long, smooth performance. Affords overload protection for hydraulic circuits as well as structural members of tools and machines due to excessive pressure build-up. KCL Ball/Spring Relief Valves and RPL Pilot Relief Valves are adjustable.