Non Return Valve

A non-return valve is fitted to ensure that a medium flows through a pipe in the right direction, where pressure conditions may otherwise cause reversed flow. ... Non-return valves are e.g. used with mixing loops in heating and cooling systems to ensure proper operation, and with domestic water systems to prevent backflow.

Non Return Valve As the name indicates, this non return valve is used to ensure unidirectional flow of fluids. It is used to prevent the back flow in order to safeguard the critical equipments such as pumps, compressor etc and also used for positive. This non return valve is also known as Check valve.