How does duckbill valve realize the backflow prevention

duckbill check valve made of elastic neoprene synthetic fibers specially processed, shaped like a beak, it said duckbill valve. In case of no internal pressure, duckbill exports itself under the action of elastic closure; With the gradual increase in internal pressure, duckbill exports gradually increased, keeping the liquid can be discharged at high flow rates. Rubber duckbill valve to prevent flooding and sewage intrusion shed street sewers and basements, to avoid heavy losses, to prevent the water level rises, flood intrusion shed sewage treatment plants, drainage pumping stations; prevent sewage smell or odor fluid diffusion, and can be any drainage; in the rainy season, to prevent urban river flood irrigation from the sewer to the street; quality is superior to shoot the door, knocked on the door to overcome some shortcomings such as closed lax.Duckbill valve, low cost, such as the use of a suitable rubber material life of more than metal valve, easy installation, flexible installation, can be repaired.
(1) maintain a high velocity jet.
(2) to prevent saltwater intrusion and sediment is one of the main properties of duckbill valve.
(3) is conducive to the discharge pipe flushing.
(4) Under certain conditions, the availability of the higher dilution.
(5) does not corrode.Duckbill Valve, widely used in the demanding applications of many industries, are precision-molded, one-piece elastomeric valves that provide reliable backflow prevention at low pressure differentials. Duckbill valves rubber allow free flow with positive differential pressure. With negative differential pressure, backflow is checked. Pressure drop across the valve is a feature unique to rubber duckbill check valve. They can be designed to operate in a few millimeters (inches) of water to several hundred kPa (psi), depending on valve size, geometry and compound characteristics. Duckbill Check Valves are also designed to start functioning at specific opening and closing pressure ranges,