Flap valves are designed to operate under very low heads of water, in gravity flow applications, at ambient conditions between -65° and +85° C. The valve prevents backwater via a spring-loaded or weighted flap placed across the opening of a pipe, tube or duct.
In Flexseal Flap Valves, the flap and back plate are manufactured in HDPE, with a stainless steel 316 hinge-pin, counterweight and attachments. Due to the specific gravity of the HDPE, a stainless steel counterweight is fitted to ensure closure when back-pressure is present; however very low heads of water are required to open the flap, as the design is such that the counterweight balances the flap correctly.
The Flap Valve incorporates a lip seal, to provide the seal between the flap and frame, and also a self-adhesive neoprene seal to install between the frame and wall, which is fitted to prevent leakage.
Flexseal offers wall-mounted flap valves up to and including 1000mm in size and spigot-mounted flap valves up to and including 600mm. Flange-mounted, tidal flap valves and bespoke flap valves are available on request.
- High quality range manufactured in the UK, already supplying to the Environment Agency and Water Companies
- Lighter weight than traditional cast iron flap valves, leading to easier installation and lower installation costs
- Heavy duty HDPE will withstand being struck by rocks and other debris, present in marine and river environments, which would shatter lighter weight plastics
- Waterproof qualities all the way through, not reliant on maintaining an added layer
- Not at risk from theft as no inherent scrap value
- Stainless steel hinges require minimum maintenance
- All models up to DN400 can withstand a constant pressure of 6 mwc as standard
- Technical support available from Flexseal
- 25 year minimum life expectancy
- Manufactured to DIN 19569-4
- Our flap valves are supplied in accordance with ISO 9001:2008 requirements