Flap Valve: an automatic backflow prevention device in water conservancy projects

In water conservancy systems, flap valve is not used in large numbers, but they very imporant. Its core function is to stop outside water and mediums from flowing back into pipeline systems.It shuts off automatically by its own weight， no need for manual supervision, super easy and convenient to use.

Working style is  simple. It mainly consists of valves Body, valve seat, valve flap, hinge and sealing parts. It is usually installed at the outlet of drainage pipes and the end of pump stations. When the water pressure inside the pipe is higher than the outside, the valve flap will open on its own, letting internal water flow out. On the contrary, once the outside pressure goes higher than inside, the valve flap will slowly close by its own weight. It seals the pipe tightly, keeping external water from flowing back into the pipeline.

In urban drainage systems, flap valves act as a key safeguard against flood and waterlogging. When heavy rain comes, urban ponding can be drained fast into rivers through underground pipe networks. When river water level rises, the flap valve closes in time, stopping river water from flowing back into the city.

For sewage treatment plants, flap valves are fitted at the outlet of pipe systems. They let treated clean water discharge smoothly, and stop outside polluted water from flowing back. This keeps the whole sewage treatment system running steadily all the time.

Flap valves are also indispensable in agriculture. They are set at the end of irrigation canals and pump station outlets. They prevent irrigation water from flowing back, help farmers control water level in canals, make rational use of water resources and avoid waste.

In coastal areas, flap valves are widely used in tide defense projects. Made of corrosion-resistant materials like stainless steel, they can stand seawater erosion. At high tide, they can prevent seawater from flowing back in, protecting cities and farmland.

Flap valves have obvious strengths. Simple structure, low failure rate, low operation cost and easy maintenance. They are widely used in urban flood drainage, farmland irrigation, sewage treatment and coastal tide prevention. It looks simple, but it’s very important.