• Google+
  • LinkedIn
  • Twitter
  • Facebook

Proportional Relief Valves (R-Series)


R Series proportional relief valves are designed to protect pressure sensitive equipment by diverting flow in order to relieve pressure upstream of pressure sensitive equipment. Relief valves open when the upstream pressure exceeds the set pressure of the valve permitting flow through the valve. Flow through the relief valve increases and decreases proportionately in response to changes in upstream pressure. Proportional relief valves reseal at a pressure lower than the cracking pressure. 

Quick Links

  • Download the Proportional Relief Valves catalog
  • Select R-Series relief valves for your application

High-Pressure Proportional Relief Valves (RH Series)

  • Maximum Working Pressure: 6000 psig (413 bar)
  • Set Pressure: 50 to 6000 psig (3.4 to 413 bar)
  • Multiple springs for a selection of set pressure ranges improve accuracy and reduce hysteresis

End Connections:

  • RH3: 1/4 in., 6 mm and 8 mm tube ends 1/4 in. NPT and BSPT pipe ends
  • RH4: 1/2 in. and 12 mm tube ends
  • 1/2 in. NPT and BSPT pipe ends

Low-Pressure Proportional Relief Valves (RL Series) 

  • Maximum Working Pressure: 300 psig (20.7 bar)
  • Set Pressures 10 to 225 psig (0.7 to 15.5 bar)
  • One spring for the full set pressure range

End Connections:

  • RL3:1/4 in., 6 mm and 8 mm tube ends 1/4 in. NPT and BSPT pipe ends
  • RL4:1/2 in. and 12 mm tube ends 1/2 in. NPT and BSPT pipe ends

General Specifications

  • Temperature Range: -40 to 275°F (-40 to 135°C)
  • Body material: 316 SS

Set and Resealing Pressures

Set pressure is the upstream pressure at which the first indication of flow occurs. Set pressure of each valve after initial relief is repeatable within:

  • ± 3.0 psig (0.20 bar) or ± 5 % (whichever is greater) of the initial set pressure at 60 to 80°F (15 to 26°C)
  • ± 6.0 psig (0.40 bar) or ± 20 % (whichever is greater) of the initial set pressure below 60°F (15°C) and above 80°F (26°C).

Resealing pressure is the upstream pressure at which there is no indication of flow. The resealing pressure is always lower than set pressure.

Proportional Relief Valve Cutaway SSP R-Series


Spring Options

  • RL Series valves are shipped with springs installed.
  • RH Series valves are shipped standard without springs.  Spring kits are purchases separately.
  • Factory set valves R Series valves are available . Valves are set, tested, locked, and tagged with the set pressure. Certificates of testing are included.
Manual Override Handles
  • A manual override handle allows operators to open the valve without changing the set pressure.

Seal Materials

  • Fluorocarbon FKM (standard)
  • Nitrile Rubber
  • Ethylene Polypropylene
  • Neoprene
  • Perfluoroelastomer FFKM
  • Other material are available on request.

Special Cleaning

Valves are available cleaned in compliance with ASTM G93 Level C and CGA G-4.1, Cleaning Methods and Cleanliness Levels for Material and Equipment Used in Oxygen-Enriched Environments. 


R Series proportional relief valves are used in gas or liquid systems in upstream and downstream oil & gas, chemical, pharmaceutical and laboratory application. They are often used ahead of pressure sensitive analyzers, flow meters and other pressure sensitive equipment or downstream from pumps and regulators to ensure protection from failures upstream of the relief valves or blockages downstream of the valve. Other applications include test labs, steam cleaning and sterilization systems, heating lines, dispensing and filling systems.

Catalog-Valves-Purge Valves
Technical & Pricing Info

Interested in a quote or more information on SSP Products & Solutions?

Or Call: 330.425.4250

Find a Distributor

To find the SSP Distributor closest to you, please visit our Distributor Locator