What is a check valve?
Check valves are available in almost every industrial application as check or one-way valves. Check valves perform a vital function to prevent backflow and ensure efficient operations. For example, reverse flow can lead to water hammer. This phenomenon can lead to repeated extreme pressure surges in connected pipes, valves and pumps that can fatally damage or rupture the system and its pipes. Even if a failure does not occur immediately, the repeated impact of water hammer can promote fatigue that can ultimately lead to a loss of system integrity.
Various rubber check valves are available that provide back flow protection against:
- sewage sludge
- Rainwater drainage
- Water discharge to a river or sea
- land erosion
- Stagnant water
- Salt and freshwater water (collection) basins
- Potentially contaminated water
- Numerous other uses.
With a single inlet and outlet, the check valves are operated by a differential pressure. Above a certain upstream pressure, the valve will open automatically without the need for any other intervention. This minimum operating pressure is one of the key features specified in all check valves. Chemicals, pulp and paper, food processing, water and wastewater treatment, marine and mining, pumps, pipelines, power generation and HVAC are among the many liquid flow and pump applications with check valves.
Check valves are regularly placed in series, for example in water systems to prevent backflow of contaminated water in clean water pipes. With a huge range of potential applications, there are also multiple types of check valves that use many different materials such as metal, polymers and rubber. Common designs include swing or valve check valves where a metal disc pivots on a hinge or trunnion to prevent backflow. Larger check valves are typically of the swing or flap type. As the name suggests, ball and spring ball check valves have a ball that mounts into a suitably profiled seat. Plant Partner’s Rubber Duck Bill Check Valves operate passively relying on a flexible rubber diaphragm that creates a valve that is normally closed unless positive pressure is applied.
Unlike their metal swing or flap check valve counterparts, rubber duckbill check valves cannot rust or seize, generally increasing reliability and longevity. Likewise, rubber check valves have no mechanical wear, a factor that can negatively affect check valves made of other materials.