Why should a non return valve be installed on the discharge side of a pump?

The valve could be a source of a transient flow leading perhaps to severe pressure waves, NRV should be installed directly downstream of the pump in order to protect the pump from any damage due to the consequences of any generated surge pressures.

What is the function of non return valve in centrifugal pump?

A non-return valve allows a medium to flow in only one direction and is fitted to ensure that the medium flows through a pipe in the right direction, where pressure conditions may otherwise cause reversed flow.

Why should a check valve be provided on the discharge side of each pump?

A check valve will be used commonly on the discharge of the pump to prevent backflow from the downstream system, when the pump shuts off. Check valves are used to prevent contaminated media in branches from flowing back into the main trunk line. Some backflow should always be expected through a check valve.

Does a non return valve be installed in vertical position?

Not all check or non-return valves will work in a vertical line. In some valves the disc will extend into the pipeline when the valve is fully open. Fitting additional valves next to one another could interfere with the performance of the check valve.

What is non return discharge?

It occurs when there is no discharge from the pump when water in the pipe, with high total energy head, returns and applies an impulsive load to the non-return valve, i.e. a ‘water hammer’.

Why should check valves be installed in the piping system?

Note: Depending on piping configuration after the steam trap, back flow can also occur in open lines if equipment goes to vacuum or if there is positive pressure from a too small vent or pipe rise which can cause unwanted return line pressure. In such cases, installing a check valve may help prevent back flow.

Why do I need a check valve?

Check valves are an important component of every submersible pump water system. Why are check valves important? First, they allow your water system to maintain pressure when the pump shuts off. They also prevent backspin, up thrust and help minimize water hammer (more on this later!).