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    Denison Unloading Valves

    Denison Unloading Valves

    Denison unloading valves offer outstanding design, high performance, fast response standardised mounting and a range of control…

    R4USubplate mounted Denison unloading valves are available with both Parker (series UR/US) and Denison (series R4U) model codes.

    These valves are used to unload a circuit at low pressure. The mechanically adjustable pressure signal to unload the main stage has to be applied to port X. The pressure differential between opening and closing is nominal 15% or 28% of the setting pressure:

    • 28% for pressure stages bar 105, 210
    • 15% for pressure stages bar 350

    Typical applications are unloading of pumps in an accumulator circuit or unloading of the low pressure stage of a double pump.

    R4U 1The R4U is available with an electrical vent valve for unpressurised circulation. Other features include: Pilot operated unloading valve, interface – subplate mounting to ISO 5781, 3 pressure stages, 2 vent valve functions, 3 adjustment modes: hand knob, acorn nut with lead seal, cylinder lock

    The Denison R4U valve is available in nominal sizes: R4U03, R4U06 and R4U10.

    Denison R5UDenison R5U pilot operated pressure unloading valves have a similar design to the subplate mounted R4U series. The SAE flanges allow to mount the valve directly on the outlet flanges of pumps.

    A typical application is the unloading of a pump in an accumulator circuit. The combination of a Denison R5U, C5V and R5V on a double pump generates a high pressure / low pressure pump system without the need of a manifold block or piping between the valves.

    Features of the R5U: Pilot operated unloading valve, 3-port body with SAE 61 flange, 4 sizes (SAE 3/4″, 1″, 1 1/4″, 1 1/2″), 3 pressure stages, 3 adjustment modes: hand knob, acorn nut with lead seal, key lock and optional vent function.

    The Denison R5U valve is available in a number of nominal sizes: R5U06, R5U08, R5U10 amd R5U12.