Parker subplate mounted unloading valves series R4U are exceptional – both in function and design – even under high flow conditions. Pacemaking in design, these valves offer improved features.

The pilot operated R4U 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 105 and 210 bar
• 15 % for pressure stage 350 bar

Typical applications are unloading of pumps in an accumulator circuit or unloading of the low pressure stage of a double pump. The R4U is available with an electrical vent valve for unpressurized circulation.

Markets:
• Industrial

Features/Benefits:
• High performance - maximum adjustable pressure of 350 bars and a flow capacity ranging from 150 l/min to 650 l/min
• Pilot stage design reduces pressure overshoot and cracking flow to a minimum - thus reducing heating, power and production losses in high pressure operation
• Precise adjustment and quick response - eliminate pressure variation and system shocks
• Short delivery time - no warehousing necessary
• 3 pressure stages - for sensitive control
• 2 vent valve functions
• 3 adjustment modes:
    - hand knob
    - acorn nut with lead seal
    - cylinder lock

Applications:
• Suitable for general hydraulic applications