A check valve, also known as a non-return valve or one-way valve, is a mechanical device used to allow fluid to flow in only one direction within a pipeline. It works by automatically opening when the fluid flows in the desired direction and closing to prevent backflow or reverse flow of the fluid. Check valves are essential components in various piping systems to prevent the reversal of flow, which can lead to damage to equipment or contamination of the system.

Check valves have several key features that make them valuable in different applications. Firstly, they offer reliable and efficient operation, ensuring that fluid flows in the desired direction without any leakage or loss of pressure. Secondly, check valves require minimal maintenance due to their simple design and lack of moving parts. They are also versatile and can be used in a wide range of industries, including water treatment, oil and gas, chemical processing, and HVAC systems. Overall, check valves play a crucial role in ensuring the safety and efficiency of fluid systems by preventing backflow and maintaining system integrity.