Non-return Valve NV100, Stainless Steel (formerly R53-ES)

Non-return valve stainless steel for the prevention of unintended gas mixtures, for flow rates up to 11,059 scfh (air), up to 362 psi, G 1/8 - 3/8

  • safety element: Non-return valve [NV]
  • every Non-return valve 100% tested
  • ultra-low opening pressures (approx. 0.0296 psi), ultra-low pressure drop
  • compact and light: 0.98 X 2.77-3.78 inches, 1.56 oz

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    WITT non-return valves for reliable protection against dangerous reverse gas flow.
    Every non-return valve 100% tested.

    The best non-return valves in the world.


    • a spring-loaded non-return valve prevents a reverse flow of gases, which could lead to unwanted gas mixtures
    • low pressure drops – using complex valve assembly with low opening pressures (approx. 30 mbar)
    • no leaks – using a spring-loaded valve assembly with elastomer sealing
    • diverse applications – useful for many technical gases
    • reduce installation costs – the spring-loaded valve is not affected by gravity and may be installed in any orientation

    Operation / Usage:

    • non-return valves are used to protect equipment and pipelines against dangerous reverse gas flow. Use is possible for applications according to EN 746-2
    • WITT non-return valves may be mounted in any position / orientation
    • the maximum ambient / working temperature is 70 °C / 158 °F


    • annual testing of the non-return valve and body leak tightness is recommended
    • WITT is happy to supply special test equipment
    • non-return valves are only to be serviced by the manufacturer

    Company certified ISO 9001
    Cleaned for Oxygen Service according to EIGA IGC Doc 13/12/E: Oxygen Pipeline and Piping Systems


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    Test Rig 722

    Test Rig 722

    For the annual testing of WITT flashback arrestors and check valves

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