Flap / Non Return Valves

HDPE Non Return Valves

A flap valve is a type of non-return valve for water or sewerage. The purpose of a flap valve is to ensure water can pass through the valve in one direction only. Flap valves operate by water flowing through a pipe or culvert and pushing the swinging door open. When the water level on the downstream side of the flap valve is higher than in the pipe or culvert it presses the swinging, door shut and prevents the water traveling back through the system.

Advantages of Flap / Non Return Valves

  • Suitable for mounting on a flat wall.
  • Entirely fabricated out of HDPE, axle and ballast weight AISI 316.
  • EPDM rubber seal in between lid and housing, housing and wall.
  • Mounting by chemical anchors or mould in anchors.
  • The valve has a maximal operating pressure of 5 mWC.


The non-return valve is used in surface water, sewers, disposal systems with a pump and other aggressive environments where return flow needs to be prevented.

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Flap / Non Return Valves Downloads