Why a safety valve is used at the discharge end of reciprocating pump?

A positive displacement pump operating against a closed discharge valve will continue to produce flow until the pressure in the discharge line has increased until the line bursts or the pump is severely damaged – or both. A relief or safety valve on the discharge side of the pump is therefore absolute necessary.

Which of the following pump do not require relief valve?

A relief valve is not necessary for a Centrifugal pump because maximum pressure with the discharge closed is only moderately above working pressure.

What is the function of the discharge line relief valve?

Relief valves are used in most pumping systems to pre- vent excessive pressures caused by changes in the conditions under which the system is operating.

What has to be considered when a pump has to be started with open discharge valve?

If you start the pump with discharge valve open, the discharge head will act on the pump ie, more resistance, so the motor has to give more starting torque to the pump which means more current is drawn by the motor. It can also be prevented by keeping the discharge valve closed.

Which valve is used in reciprocating pump?

Non-return valves Reciprocating pumps, like reciprocating compressors, require inlet and outlet valves to ensure the liquid always travels from inlet to outlet. The valves are non-return valves, for a very dynamic application.

What is the purpose of providing an air vessel at the discharge of a reciprocating pump?

The vessels are used for the following purposes: (i) To get a continuous supply of liquid at a uniform rate. (ii) To save the power required to drive the pump. This is due to the fact that by using air vessels, the acceleration and friction heads are reduced.

What is a discharge line?

A discharge line is a section of piping where the pressure is higher than atmospheric pressure (e. g. Pump system).

Is a pressure relief valve necessary for?

A pressure Relief Valve is a safety device designed to protect a pressurized vessel or system during an overpressure event. The pressure Relief Valve must open at a predetermined set pressure, flow a rated capacity at a specified overpressure, and close when the system pressure has returned to a safe level.

Why must you secure the discharge line before starting a high pressure pump?

For low to medium specific speed pumps (below values of approximately 5,000), close the discharge valve prior to stopping the pump. This takes the load off the motor and, if any check valves leak, it may prevent reverse flow through the pump.