DN600 PN16 Weather Resistant Rubber EPDM Flanged Duckbill Duckbill Non Return Valve
 
 
Basic structure of flange duckbill valve
Flange duckbill valve is a valve that uses a rubber duckbill structure to achieve a one-way check function. It is installed in the pipeline system through a flange connection and is mainly used to prevent fluid backflow.
 
 
Composition
Valve body: usually metal (such as cast iron, carbon steel, stainless steel), with flange interface.
Duckbill part: elastic rubber material (such as NBR, EPDM, neoprene), flat duckbill shape, open and close with fluid pressure.
 
Working principle
Forward flow: fluid pressure opens the duckbill and the medium passes through.
Reverse flow: The duckbill closes under the action of back pressure, relying on elastic seal to prevent backflow, similar to the function of a one-way check valve.
 

 
 

 

 
 
Material selection
Valve body material: Cast iron, ductile iron, 304/316 stainless steel are selected according to the medium.
 
Duckbill material:
EPDM: Ozone resistant, aging resistant, suitable for -20℃~120℃.
NBR: Good oil resistance, suitable for oily wastewater.
Fluororubber (FKM): Resistant to high temperature (150℃) and strong corrosive media.
 
 
Core features
No mechanical parts: Relying on rubber elasticity, simple structure, low failure rate.
Self-cleaning design: Impurities can be flushed during opening and closing, suitable for media containing particles and fibers.
Low head loss: The flow channel is smooth when fully open, reducing pressure
 
 
Application areas
Drainage system: Municipal rainwater and sewage pipe network, pump station outlet.
Industrial field: Corrosive medium transportation in chemical and paper mills.
Environmental protection engineering: Seawater desalination, anti-backflow at the discharge outlet of sewage treatment plants.