Non-Return Valve NV300

Non-Return Valve NV300

Non-return valve for the prevention of unintended gas mixtures, for flow rates up to flow rates up to 322,118 scfh (air), up to 232 psi, for use in thermal processing plants, certified to EN746-2

  • safety element: non-return valve [NV]
  • every non-return valve 100% tested
  • protects against flashbacks, for fuel gas-compressed air-mixtures
  • ultra-low opening pressures (approx. 0.0508 psi), ultra-low pressure drop
  • ideal for biogas desulphurization systems
  • dirt filter (100 μm) on gas inlet
  • 2.54 X 4.49-5.07 inches, 62.72 oz

This model is also available in Stainless Steel

Product of WITT 




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


  • a spring-loaded non-return valve (check 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 NV300 – approx. 3.5 mbar
  • no leaks – using of a spring-loaded valve assembly with elastomer sealing
  • stainless steel filter (100 μm) in the gas inlet protects the non-return valve against dirt contamination, extending the service life
  • 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 (check valves) are used to protect equipment and pipelines against dangerous reverse gas flow. Use is possible for applications in accordance with EN 746-2
  • non-return valves (check valves) are proved in accordance with EN 730-2. They may also be used as a safety device to protect against flashbacks (proved in accordance with EN 730-1 point 6.7), which may result from the combustion of natural gas/ LPG with air
  • WITT non-return valves (check 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 (check valve), body leak tightness and flow capacity is recommended
  • WITT is happy to supply special test equipment
  • non-return valves (check valves) are only to be serviced by the manufacturer. The dirt filter may be replaced according to model by competent staff

Company certified to ISO 9001 and PED 97/23/EC Module H
CE-marked in accordance with PED 97/23/EC
Cleaned for Oxygen Service according to EIGA IGC Doc 13/12/E: Oxygen Pipeline and Piping Systems


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Non-Return Valve NV300