Flap valves prevent reverse flow conditions of surface water drainage associated with rivers, estuaries and sea water outfalls . Flap valves prevent flood damage on final effluent outfalls of sewage treatment plants.
Position the flap vales on the outfall structure. This avoids build-up of debris around the invert area which could prevent the valve operating correctly. Sufficient fall-away between the invert of the flap valve and the base of the outfall structure is essential.
Flap valves are for all types of pipe end closures to prevent entrance of back water.
An inclined seating plane ensures that the valve will operate a ‘positive close’ position.
Flap valve application on sea water outfalls should be given careful consideration due to turbulence of flow across the flap. Particularly when severe wave action is involved, resulting in dislocation of the flap relative to its seals. Wherever possible the flap valve should be located in a shielded position to minimise the effects of severe wave action.
Ham Baker manufactures a comprehensive range of flap valves. Generally, most flap valves are of single door type but double door types are also available. The cast iron series of flap valves is constructed from traditional materials utilising the most modern production techniques to provide a robust and reliable product.
Flap valves can be supplied for wall, flange or thimble mounting applications
This range of flap valves has a circular aperture, single door and double hinges. For flap valves up to 600mm dia the sealing faces are of angular section and secured to the frame and door by a force fit.
For sizes above 700 to 2000mm dia the sealing faces are of rectangular section and are secured to the frame and door using countersunk taper headed screws in the same material as the sealing face.
The flap valve is suitable for mounting on a vertical wall or flange for static seating heads up to 6 metres.
- Fixing Bolts available on request
Flap valves for flange mounting are supplied with connections to BS EN 1092-2: 1997. PN16 rated flanges as standard.
Certain sizes have alternative drillings as standard.
Note: At least 300mm fall away to be provided at the invert as it prevents fouling of the bottom of the door.