Product Type: Headwall Flap Valve
Model Type: MULTI - NB
Nominal Diameter: 500mm
Body & Flap - Glass reinforced plastic using an isophtalic polyester resin with surface isophtalic gel coat
Hinge - Self-lubricating Ertacetal plastic
Seal - Ethylene Propylene Diene Monomer (EPDM) to BS EN 681-1
Fittings - Grade 1.4401 (316) austenitic stainless steel to BS EN 10088-2
Valve Bolt Holes:
Pitch Circle Diameter – 620mm
No. of Holes – 4
Dia. Of Holes – 10mm
Approx. Weight: 9.7kg
This Mission headwall flap valve is designed with an inclined flap, PN 10 flange and integral EPDM rubber sealing rings for sealing to concrete headwalls. Its principal applications are for surface water drainage associated with river, estuary and sea water outfalls to prevent backflow into the sewer, and for final effluent outfalls from wastewater treatment works to prevent flood damage within the works.
Product Features at a Glance:
- Lightweight for fast and easy installation
- Inclined flap for additional security against backflow
- No need for cement grout when fixing to headwall
- Hinged design ensures flap closure when no discharge
- Resistant to 1bar (10m head)
Product Dimensions (see dimensional drawing product image for reference)
- General Locations - Flap valves should be fixed so as to avoid the accumulation of debris around the invert which could prevent the valve operating correctly.
- Tidal Locations - Turbulence of flow due to severe wave action will shorten the working life of a flap valve. Therefore it is recommended that careful consideration is given to the positioning of valves and they are installed within an outfall bay or otherwise protected from direct wave action by baffles.
Mission Flexible Drainage Fittings
Mission Rubber (UK) Ltd is part of the worldwide Mission Rubber group of companies who, over 50 years ago, invented the flexible rubber coupling for the sewerage, drainage and plumbing industries. Since then Mission has grown to become the world´s No 1 manufacturer of rubber flexible couplings with manufacturing plants in both America and Europe, and distributors worldwide.
Flexible rubber drainage fittings offer a perfect solution to joining pipes of various materials in drainage, sewerage and plumbing installations. They consist of a rubber body with stainless bands that enable them to compress down uniformly, onto different sizes and types of pipe, to form a reliable, airtight and watertight seal. It is a robust design that is aided, in some couplers, by a centre shear band which provides resistance against heavy earth loads and shear forces, helping to ensure pipe alignment with joint flexibility.
Flexible rubber fittings are ideal for joining plastic drainage pipes to other drainage materials such as clay, concrete, twinwall, stainless steel, cast iron and pitch fibre.
Key Features of Mission Fittings:
- Unique “Lock In Place” Rubber Profile
- Made from EPDM rubber
- Ensures clamps and shear band are properly positioned
- Remain firmly in place during transit, stocking or installation on site
- Internal stepped sealing lines achieve a better sealing effect
- Additional EPDM sealing material can be compressed through sealing lines - giving special advantage for sewer pipes with rough surfaces e.g. concrete pipes
- TOX - TECHNOLOGY Clinching Process
- No spot welding of clamps to the shear band- heat created during the welding process burns the stainless steel
- Eliminates negative aspects associated with spot welding
- Bond meets or exceeds all relevant tensile strength and shear requirements
- Incorporated in the shear bands on all Mission couplings
Please Note: All images shown are used for illustration purposes only and may differ from the actual product supplied.
- 5 - 7 working days
- Product Type:
- Drainage fitting
- Install Type:
- Flap Valve