M&S Non-return valves

M&S non-return valves are used in process engineering plants to prevent the flow reversal of fluids (liquids or gases) in pipelines.

For example, they prevent the liquid column in a riser pipe from flowing back if a feed pump fails.

For dosing tasks or the merging of fluids, in the event of a pressure difference, penetration into the pipeline with the lower pressure is prevented.

M&S non-return valves are available as between flanges type or screwed type. 

  • To prevent the reversal of flow
    • for liquids in rising pipes
    • when combining liquid or gaseous media or dosing, especially with pressure differences in the pipelines.
  • To prevent idling of pipelines or pumps.
  • Installation in vertical and horizontal pipelines
  • Low pressure loss
  • Reliable and robust design
  • With unbreakable spring even with frequent operations
  • With external marking for flow direction
  • Between flanges type for easy disassembly even in rigid pipelines
  • Special versions on request
    • NRV MW with screwed-in O-ring in the valve disc (for use with high flow velocities or vacuum)
    • NRV MW with double bearing of the valve shaft ( for hight switching frequency in horizontal installation)

Non-return valve

screwable version

Non-return valve

version between flanges


DN 25 – 100 / 1“ – 4“ 
Ausführung: GS

DN 25 – 150 / 1“ – 4“ 
Ausführung: ZF


304/304L – 1.4301/1.4307

316L – 1.4404




In contact with product
Ra ≤ 1,6 µm
Not in contact with product
Ra ≤ 3,2 µm

Finish = lathe clean