Duckbill valve commonly known as: rubber discharge check valve, also known as: sewage rubber check valve, check valve rubber, rubber check valve, soft shape of the check valve, duckbill-shaped rubber flat mouth valve. 
 The main products are: XH81, XH81A, XH41, XH41A rubber discharge valve; the valve can give straight pipe, flange pipes, cement pipes, glass pipe support, the valve is widely used in coastal, beach, pier, reservoir , municipal drainage, sewage, can be called green environmental protection valve, take the door replace the valve, check valve, making the door easily solve the sediment, silt, rocks, vegetation, marine life blocking problem. 
 Flanged Check Valve Rubber Products sewage main purposes: used in water systems, drainage systems, water pumps export, pump stations and liquid aeration system. Main features: rubber flange and valve body into one, very easy to install . Design with full rubber body, will not cause siltation and things stuck phenomenon, reducing maintenance costs, and allow the smooth adoption of solid particles. Valve Manufacturing materials: chloroprene rubber, Haipu Long, NBR rubber and ethylene-propylene rubber; flange material: Q235, 304,316 and so on. 
 Duckbill valve flange size standards: There are two popular terms of installation size. A mounting flange dimensions to national standards, provides for the following caliber duckbill valve 800 flange standard ten kilograms of mixed national standard center distance and the flange bolt hole diameter, diameter more than 800, with reference to the national standard of 6 kg and the bolt hole center distance flange diameter. 
 Installation method and size: the rubber flange, and the duckbill valve body made of metal flange with a gasket, the natural connection with the metal flange, directly on the tanks, pipes, and on the cofferdam. Installation and connection, the flange and flange dimensions correspond to guarantee the absolute connection after fastening seal, but also be careful not to damage the rubber flange lips sewage check valve. 
 Duckbill valve installation 
 Straight lift check valve should be installed in horizontal pipeline, vertical lift check valve and bottom valve is usually installed in a vertical pipe on the road, and the media bottom-up flow. 
 Swing Check Valve improper installation location restrictions, usually installed in horizontal pipeline, but can also be installed on vertical pipe or the tilt control on the road. 
 Check valve should pay particular attention to the direction of media flow, should make the media the normal flow direction and the direction of the arrow on the valve body in line, otherwise you will cut off the normal flow of media. The end of the valve should be installed in the pump suction pipe at the bottom. 
 Check valve is closed, will be in the pipeline water hammer pressure can cause serious valves, piping or equipment damage, especially for big mouth pipe or high pressure pipeline, it should cause those who use a high degree of valve attention. Straight lift check valve should be installed in horizontal pipeline, vertical lift check valve and bottom valve is usually installed in a vertical pipe on the road, and the media bottom-up flow. 
 Advantages and disadvantages of duckbill valve 
 Advantages: low cost, duckbill valve, such as the use of appropriate rubber material life of more than metal valve, easy installation, flexible mounting, can be repaired. 
 Cons: rubber body does not apply to long-term leak-day field operations, the use of high-quality rubber can not avoid aging.