The Non Return Valve (NRV), also known as a check valve, is a mechanical device designed to allow fluid to flow in one direction only and automatically prevent reverse flow in pipelines. It operates without manual intervention, using internal mechanisms such as a disc, ball, or swing type that closes when the flow reverses, protecting pumps, compressors, and piping systems from damage, back pressure, and water hammer. Typically manufactured from materials like cast iron, ductile iron, or stainless steel, the valve is available in various types including swing check, lift check, and ball check, with different pressure ratings such as PN10 and PN16. It is widely used in water supply systems, irrigation, sewage treatment, and industrial applications due to its simple design, reliable operation, low maintenance, and long service life.
