duckbill check valve water flood diffuser - The Rhinoflex duckbill check valves are a very reliable and a good, economical alternative to flap-gate valves as well as other check valves. The simple one-piece design and reinforced rubber construction remove the mechanical and metal components that rust and seize in conventional flap-gates. They are made to order, one of the ways , non-return check valves, made out of a number of elastomeric rubbers, and built as per the application as well as the line pressure and back pressure concerned. These come in all standard pipe sizes, and typical application is back flow prevention and downstream of an pump, at pump stations.