A Non-Return Valve (NRV), also known as a check valve, is a mechanical device that allows fluid (liquid or gas) to flow in one direction only and automatically prevents reverse flow. It operates without manual control, using the pressure of the flowing fluid to open the valve and closing automatically when the flow stops or reverses. This simple yet essential function helps protect pipelines, pumps, compressors, and other equipment from potential damage caused by backflow.Non-return valves are widely used in industries such as water supply systems, oil and gas, chemical processing, power plants, HVAC systems, and food and pharmaceutical production. By preventing backflow, they maintain system efficiency, reduce the risk of contamination, and improve overall safety.There are several common types of non-return valves, including swing check valves, lift check valves, ball check valves, and dual-plate (wafer) check valves. Each type is designed to suit specific flow conditions, pressure ratings, and installation requirements. The choice of valve depends on factors such as fluid type, operating pressure, temperature, and maintenance considerations.
