The accumulator

Accumulators are used:

when the system needs a considerable flow during a short period;

when the system or a part of the system has to be kept under pressure;

to accumulate peak pressure or pressure vibrations;

as a cushioning element.

In hydraulic systems the following types of accumulators are used:

the piston accumulator; animation (to supply oil; reliable; relatively slow accumulator as a result of friction between piston and cylinder)

the bladder accumulator (to supply oil; 'fast' accumulator)

the diaphragm accumulator (cushioning element; pressure compensator)

This example explains the functioning of the piston accumulator (animation) ; the functioning of the other types is similar to this one. At one side of the piston the accumulator is filled with nitrogyn gas. The pressure of the gas at the gas side of the accumulator has to have a certain pressure, in this case 80 bar (8 MPa). This pressure, prescripted by the manufacterer of the system, has to be checked when there is no oil at the other side of the piston.

At the moment that the accumulator is filled with oil, the pressure at the oil side increases to the level of the gas pressure immediately. In the animation you can see this happen. For an appropriate functioning of the system, the gaspressure has to have the right value. The manufacturer prescribes how often the pressure has to be checked.

Watch out: accumulators accumulate hydraulic energy and therefore can be very dangerous, especially when you are not familiar with the system and accumulators!!

The accumulator

When repairing or modifying a hydraulic system be sure that the accumulator is drained and shut off as instructed by the manufacturer!