Check valves are critical components in many pumping, fluid flow and piping systems. They prevent reverse flow in a system as long as the flow pressure is maintained or higher, thus protecting the downstream equipment from damage caused by backflow.
A wide variety of different types and styles of check valves are available, including ball, flap, piston and stop check valves. All of them function to protect a piping system against reverse flow by allowing flow in one direction while inhibiting backflow through the other.
Duckbill Check Valves are a versatile and reliable option for backflow prevention. They offer a simple, rugged design with no moving mechanical parts and are highly resistant to corrosion and wear and tear.
They can be used in sewage treatment, effluent discharge, stormwater outfall and ponds as well as for flood control and wet wells, and are typically installed with mating flanges between two pipes. They are also extremely robust and require no maintenance, making them ideal for use in environments with corrosive and hazardous materials, suspended solids and organic contaminants such as algae, barnacles and abrasives.
The duckbill check valve consists of a rubber or other elastomeric component with a flattened end that compresses around trapped and suspended solids, preventing backflow. This compression also provides a tight seal when the differential pressure exceeds the valve’s cracking pressure, even when the fluid is still pressurized.
A duckbill check valve can be designed to operate at pressures from several millimeters (inches) to hundreds of kPa. Depending on the valve size, geometry and compound characteristics, it may be configured to start functioning at certain opening and closing pressures, as well as adjusting the backflow protection depending on the differential.
Because of their unique construction, duckbill valves are highly flexible and can compress more around trapped and suspended solids than other types of check valves. This enables them to seal better, and can eliminate the need for upstream backpressure reduction devices such as bypass valves.
In addition, duckbill check valves are easy to install and can be fitted into a variety of pipe sizes. They are also a great choice for installations where high flow rates or long service life is important, as they can be easily repositioned and replaced if needed.
Duckbill check valves are made from the highest quality, fire-retardant elastomeric material that is resistant to corrosion and wear, and provides excellent abrasion resistance. They can also withstand large obstructions without jamming or binding, and guarantee trouble-free backflow prevention, sealing around trapped or suspended solids with minimum backpressure.
Another advantage of duckbill check valves is their extreme longevity, which makes them a good investment. They can be expected to last between 35 and 50 years, which is much longer than typical mechanical check valves that would require replacement after only a few years of service.
As with any check valve, they should be checked regularly to make sure they are working properly. It is especially important to inspect them after bumping, sharp objects scratching, away from heat sources and high temperatures during use and storage.