Type 636/631

> Safety valves with bronze body
> Enclosed discharge valve with threaded connections

Product Description

Type 636/631

Enclosed Discharge Safety Relief Valve for Compressed Air & Gases, available with 10, 13, 18, 20 or 25mm nominal bore


Example Applications:
  • Air/gas compressors
  • Pressure vessels
  • Pneumatic systems
  • Medical gases
  • Technical gases



View or Download Datasheet

Type 636 & 656 (Enclosed Discharge Safety Relief Valve for Compressed Air & Gases)

Technical Information for Type 636 & 656

  • Min. Pressure
    6.6 bar (95.7 psi)
  • Max. Pressure
    55.20 bar (800.40 psi)
  • Temperature Range
    -30°C to 200°C (subject to seal material)
  • Inlet Connection(s)
    3/8" to 2" BSP, BSPT or NPT
  • Outlet Connection(s)
    3/4" to 2" BSP or NPT
  • Flow Rate
    Refer to Flow Tables on the datasheet
  • Materials
    Bronze & Brass or Bronze & St. Steel or St. Steel
  • Seal Materials
    Viton® / Nitrile / Neoprene Ethylene / Propylene
  • Test Certification
    Included - supplied Free of charge
Flow Rates:

See Datasheet

  • The maximum permissible built-up back pressure is 10% of the set pressure
  • Stable operation on flows down to 50% of valve-rated capacity
  • Relieving pressure is set pressure +10%
  • Reseating pressure is set pressure -10% (0.3 bar minimum)
  • Below 1.55 bar, PED certified only


  • Designed in accordance with BS EN ISO-4126-1 & -7
  • PED 2014/68/EU (CE)
  • PE(S)R UK SI 2016 No. 1105 (UKCA)
  • CRN
  • EAC


Proactive Risk Management

Investing in pressure relief valves is a proactive approach to mitigating pressure-related risks, and safeguarding equipment and personnel from potential incidents.


View or Download the Type 636 / 631 Datasheet

Full Technical Information - Including Flow Rates

View or Download the Type 636 / 631 Datasheet

Seetru offers a wide range of downloadable datasheets for our products, including safety relief valves, liquid-level gauges, and sight glasses.  These datasheets provide detailed information on the technical specifications, features, and applications of Seetru products.  They are an essential resource for engineers, designers, and other professionals who need to select the right Seetru products for their specific needs.


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Visit our Downloads Page View the Type 636 / 631 Datasheet