Accumulator

The accumulator's internal space is divided into two parts by a gas bladder: one part is filled with nitrogen, and the other part is filled with hydraulic oil. When the hydraulic valve forces hydraulic oil into the accumulator, the gas bladder deforms under pressure, and the gas volume decreases as the pressure increases, gradually storing the hydraulic oil. When the hydraulic system needs the hydraulic oil to operate, the accumulator releases the hydraulic oil to compensate for the system's energy needs.
In the case of hydraulic circuits where a large flow rate is required for a short period, alternating with a low or no flow condition, the use of an accumulator allows smaller pumps and motors to be used, thus reducing both installation and operating costs. The operation cycle shown in fig.2 would require a pump having a capacity Q2. If an oil-pneumatic accumulator is used, it is possible to store oil during the time periods (t2-t1)and(t4-t3) when requirement is very low or zero, and to re-utilize. During t1 and(t3-t2), when the required flow rate is higher than the pump capacity Q1. This pump must be selected to have the volumes V1+V2≤V3+V4.