Cast Check Valve are designed to respond to pressure differences. Throughout the life cycle of the valve, there are instances where the pressure of the fluids traveling through the valve is greater than the pressure across the valve mechanism. The force of upstream water creates high differential pressure across the interior valve body, so the valve opens, allowing forward streams to pass through. However, back-flowing water lowers differential pressure across the valve body, so the duckbill elastomer valve flexes closed, sealing debris out.
Now, the duckbill elastomer check valve is routinely used in backwater prevention and waterway applications. The curved shape of the interior valve bill can regularly achieve a tight closed position, providing an excellent seal against debris in backflow applications. Various duckbill models have been engineered for low pressure applications, and for pollution prevention efforts on larger waterways.
Modern valves are engineered to respond to modest pressure changes. These newer valves respond to slight changes in differential pressure from forward- or backflow, making them useful for a variety of environments. Unlike check valves with metal components, such as disc check valves, duckbill elastomer Swing Check Valve require significantly less maintenance - they lack interior metal components that can rust or become corroded.