Rubber Duckbill Check Valve

‌Rubber duckbill check valve‌ (also known as flexible check valve or sewage check valve) is a one-way valve made of elastic rubber material (such as chloroprene rubber, nitrile rubber, etc.), named because of its duckbill shape. Its core structural features include:

‌All-rubber integrated design‌: no mechanical moving parts, built-in nylon cord reinforcement layer to ensure flexibility and pressure resistance;
‌Sealing component‌: using special rubber formula (such as EPDM or fluororubber), corrosion-resistant, wear-resistant, suitable for harsh media such as acid, alkali and salt;
‌Connection method‌: support flange connection (GB/T 9113 standard) or clamp connection, suitable for cement pipe, fiberglass pipe and other pipe types.

Working principle
‌Forward flow opening‌: The medium pressure acts on the inner wall of the valve nozzle, and the flexible rubber deforms and expands to form a flow channel; ‌Reverse flow blocking‌: When the medium pressure disappears or flows back, the elastic rubber quickly returns to the closed state to achieve zero leakage sealing; ‌Self-cleaning function‌: The streamlined flow channel design reduces siltation, and high-speed water flow can wash away sediments.

1. Nominal diameter range
The specifications of rubber duckbill check valves cover DN50~DN3000, which can meet the needs of different scenarios:

DN50~DN600: suitable for small pumping stations, community drainage pipe networks and other scenarios;
DN800~DN1800: mainly used for medium and large projects such as municipal trunk pipe networks and storage tanks;
DN2000~DN3000: specially designed for large water conservancy projects (such as reservoir flood discharge and inter-basin water transfer).
2. Connection method
Clamp connection: suitable for fast installation requirements, commonly seen in DN300~DN500 specifications;
Flange connection: in accordance with GB/T 9119 or ANSI B16.5 standards, DN50~DN3000 full series support;
Embedded installation: stainless steel anchors are required, suitable for large valve body pre-embedded with DN≥1500.
3. Pressure level
‌Normal working conditions‌: Pressure level PN10 (1.0MPa), meeting more than 90% of municipal drainage needs;
‌High-pressure scenarios‌: Customizable PN16 (1.6MPa) or higher pressure models, suitable for industrial wastewater and water conservancy projects;
‌Reverse sealing pressure‌: Customized according to backflow pressure (such as tides, waterlogging conditions).
4. Performance parameters
‌Flow resistance coefficient‌: High-quality valve body ≤0.5 (traditional flap door ≥3.0);
‌Opening pressure‌: ≤0.01m head (100Pa), ensuring normal drainage at low water level;
‌Applicable media‌:
Ordinary sewage (chloroprene rubber);
Oil-containing, corrosive wastewater (nitrile rubber or fluororubber).

 

rubber duckbill check valve

 

Applications
Municipal drainage system: prevent sewage from backflowing into streets or basements, suitable for DN50~2000mm pipes;
Coastal flood control project: tidal drainage of docks and beaches, resisting seawater corrosion and silt blockage;
Industrial wastewater treatment: one-way discharge control of sulfur-containing and oil-containing wastewater pipelines in chemical plants;
Water conservancy facilities: prevent backflow at reservoir flood discharge outlets, replacing traditional metal flap doors that are easily blocked.

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