Accumulators are used to minimize the pressure variation of the liquid. When the liquid pressure is too low, or too high the accumulator starts to balance the pressure. Accumulators are suitable for applications up to 345 barg.

The accumulator has a pressure vessel and a bladder. The pressure vessel is piped to the process system. The bladder is attached to the other side of the pressure vessel and is charged with nitrogen. When the liquid is processing, the nitrogen in the bladder is compressed to a higher pressure as its volume is reduced.

When the pump can't match the demand, the system pressure will drop. When the pressure of the process liquid drops, the nitrogen in the bladder expands and pushes an amount of liquid from the vessel into the system. When the process pressure in the system is greater than normal the accumulator will be recharged.

The gas pressure within the bladders should be checked on a regular base and should be refilled when necesarry. Large pumps do not always stop immediatly when the power is switched off. They usually have a deceleration time that varies from 30 seconds to a minute.