Air Vessel Function in Reciprocating Pump

Reciprocating pumps deliver fluid in distinct strokes, causing pulsating flow and pressure fluctuations, especially on the discharge side.

An air vessel is incorporated, typically on the discharge pipe near the pump outlet. It consists of a closed chamber partially filled with air (or another gas) and the rest with the fluid being pumped.

• During the pump's delivery stroke, excess fluid enters the vessel, compressing the trapped air. This stored energy helps to maintain flow when the pump stroke is less forceful or during the return stroke.
• During the suction stroke, the compressed air expands, pushing fluid out of the vessel into the discharge pipe.

This mechanism effectively dampens the pulsations, converting the intermittent discharge from the pump into a relatively continuous and uniform flow stream. This ensures a steadier supply of water at a uniform rate.

Therefore, the primary reason for using an air vessel is to achieve a continuous and uniform rate of water supply.