A flap valve is a top-hinged non-return cover on a pipe outlet or wall discharge. Outflow pushes it open, and reverse water pushes it shut. It has no screw hoist and no winch. A sluice gate is a different machine: a leaf that slides in a frame and is opened by a hoist.
Terms
Flap valve. A circular cover hinged at the top. It is also called a tide gate or a non-return outlet gate. It works by the difference in water level. No operator is required.
Cast iron flap valve. A cast circular flap valve with a domed cover and a flanged base. One published size is DN500. Other DN sizes are made in the same series for municipal and irrigation drainage pipelines.
Steel flap valve. A fabricated circular flap for a pipe outlet or a wall discharge, fixed by a bolt flange. A reinforced steel flap valve adds welded ribs and a heavier top hinge pin where reverse pressure or debris impact needs a stiffer leaf.
Sluice gate. A sliding leaf in a frame, used to open or close a clear opening. It stays where the hoist leaves it. It does not swing open by itself.
Bottom-hinged steel flap gate. A welded steel leaf that pivots on a bottom hinge and is moved by a hydraulic cylinder. It is a powered culvert or outlet gate, not a free-swinging flap valve.
Hebei Dequn Water Conservancy Machinery Co., Ltd. supplies both kinds. The free-swinging range includes a DN500 cast iron flap valve, a circular steel flap valve for pipe outlets, and a reinforced steel circular flap valve. The powered range includes a hydraulic bottom-hinged steel flap gate for culverts and outlets. The cylinder and hydraulic power unit on that gate are taken from the drawing.
Use a flap valve where water should leave a pipeline or a wall opening and should not flow back in, and where nobody needs to hold the leaf partly open. Use a sluice gate where the opening must be set, held, and closed under a stated design water head. Use a bottom-hinged steel flap gate where the leaf must be driven on a bottom hinge rather than left to swing on a top hinge.
Questions and Answers
Q: Does a flap valve need a hoist?
A: A cast iron flap valve or a steel flap valve does not. Outflow opens the top-hinged cover, and reverse flow closes it. A bottom-hinged steel flap gate is different: a hydraulic cylinder moves that leaf.
Q: Is a flap valve the same as a penstock or a slide gate?
A: No. A penstock or slide gate on this site is a sluice gate. Its leaf slides in a frame. A flap valve swings on a top hinge at a pipe outlet.
Q: When is the steel flap reinforced?
A: When reverse pressure or debris impact needs a stiffer leaf than a light cover. The reinforced steel circular flap valve uses welded ribs and a heavy top hinge pin.
Q: What should be sent for a quotation?
A: Send the outlet diameter or DN, whether the body is cast iron or steel, the mounting (pipe flange or wall), whether reverse flow or debris is expected, and whether the duty is a free flap valve or a hydraulic bottom-hinged flap gate. Export / International Sales: +86 13903193904, sales@dequnwater.com.
Hebei Dequn Water Conservancy Machinery Co., Ltd. is the operator of this website, which serves as the official overseas website for Dequn's global B2B operations. The factory is in Xinhe County, Xingtai City, Hebei Province, China.
