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.

Testimonial: Rayne Precision Engineering

I have passed your cards onto a couple of our maintenance contractors and have given you a high recommendation to them both, so hopefully they too will be using in the future. Thanks for helping to get our repair solved so promptly.

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Testimonial: Engineering Solutions

The valve arrived about 9:00am this morning. The service from you and Steve has been first class, so thank you very much. I shall certainly use your services again and recommend you to others. Thanks again and best regards.

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Testimonial: Philippines

We would like to confirm receipt of your shipment for our initial order: PO# 07623. It was a pleasure having started working with you and we hope this is just the start of a good business relationship between our companies. Again, thank you very much and we look forward for more future business opportunities with you.

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Testimonial: The Netherlands

Thank you for your service with selecting the proper pump. Pumps have arrived this morning and they completely conform with the old pumps.

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Testimonial: Abernethy Trust

Please pass on my thanks to Steven for great customer service and his product knowledge; our gang mowers are back up and working.

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Testimonial: Virginia

Please thank your team very much in helping me solve a pump issue. I needed a pump that was manufactured by a company no longer in business, and Steven was able to locate a duplicate that was manufactured by Parker.

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Testimonial: Gwynedd

Thank you, Joanna. Mark’s quote was from a technical discussion which answered many questions that I have been trying to get without success from other suppliers. Please thank Mark for his time and expertise; it was so refreshing to have a knowledgeable person rather than a sales assistant.

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Testimonial:Missouri

Just wanted to tell you that the pump fits and works perfectly. You were a big help, thank you.

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Testimonial: Lift Company

Hi Mark, Thanks for sorting this out for me so quickly. Absolutely brilliant service… In this day and age it is so rare to come across a company with customer service to this level. Much appreciated.

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Testimonial – Perth

Can you let the boys know that they are providing us with great service, parts and information in all our locations. Your service is prompt and reliable; you’re our “go to” guys when it comes to hydraulics.

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