duckbill check valve water flood diffuser - The Rhinoflex duckbill check valves are an exceptionally reliable and a very good, affordable replacement for flap-gate valves as well as other check valves. The straightforward one-piece design and reinforced rubber construction get rid of the mechanical and metal components that rust and seize in conventional flap-gates. These are generally customized, one way , non-return check valves, made out of various elastomeric rubbers, and built as reported by the application along with the line pressure and back pressure concerned. They come in all standard pipe sizes, and typical application has returned flow prevention and downstream of the pump, at pump stations.