ABOUT HYDRAULIC ACCUMULATORS

The circuit element that stores pressure energy in hydraulic circuits and gives this energy very quickly when needed in the system is called hydraulic accumulator. Hydraulic oil must be compressed in order to be stored under pressure. Since the compression properties of hydraulic oils are weak, nitrogen gas is used in hydraulic accumulators. The nitrogen gas in the accumulator is compressed by the pressurized hydraulic oil acting on the separation element, its volume is reduced and its pressure increases, and the decreasing gas volume is replaced by hydraulic oil. Thus, pressurized hydraulic oil is stored in the accumulator.

WHY ARE ACCUMULATORS USED?

A hydraulic system may require different flow rates during the cycle. In such a case, it is necessary to choose a hydraulic pump and electric motor large enough to provide the highest flow rate needed for the system to operate. In order to reduce the initial installation cost and energy consumption of the system, we can use an accumulator to meet the high flow rate required by the system in a short period of time. When the pump flow rate is more than the system needs, the accumulator is filled, and when the pump flow rate is insufficient, the oil stored in the accumulator can be used.

In applications such as long-term locking, holding, tensioning, etc., the pressure in the system must be maintained. Even though solutions such as locking valves etc. are used in the system, the system pressure will decrease due to leaks and the pump will need to be activated frequently. In such applications, accumulators slow down the decrease in system pressure by compensating for leaks.   

Apart from the above reasons, hydraulic accumulators are also used in hydraulic systems to absorb impacts, shocks and vibrations. These vibrations and shocks may occur due to the closing of valves, intermittent oil transfer due to the nature of the pumps, or the effect of an external force. Thanks to the damping with the accumulator, the life of all circuit elements will be extended.

It is also possible to use hydraulic accumulators to balance the expansion caused by temperature in closed circuit systems or the change of counter force in rolling applications.

Another purpose of use of accumulators is emergency applications. In dangerous situations that may arise in the circuit, damage can be prevented by stopping the process very quickly with the help of the accumulator, or in cases of power outage, the hydraulic accumulator can be activated and used to lower the loads to zero position, and to open or close doors or covers at the completion of the cycle.