Hydraulic Accumulator

Hydraulic Accumulator

Hydraulic Accumulator

What is Hydraulic Accumulator? What Does It Do?

What is a Hydraulic Battery?

The circuit element that stores the pressure energy in the hydraulic circuits and gives this energy very quickly when needed in the system is called the hydraulic accumulator. In order for the hydraulic oil to be stored under pressure, it must be compressed. Due to the poor compression properties of hydraulic oils, nitrogen gas is used in hydraulic accumulators. Nitrogen gas in the accumulator is compressed by means of pressurized hydraulic oil acting on the separation element, while its volume is reduced, its pressure also increases, and hydraulic oil replaces the reduced gas volume. Thus, pressurized hydraulic oil is stored in the accumulator.

Where is the Hydraulic Battery Used?

In a hydraulic system, there may be different flow needs 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 required for the system to work. 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 that the system needs for a short time. When the pump flow is more than the system's need, the accumulator is filled, and in cases where the pump flow is insufficient, the oil stored in the accumulator can be used.

In long-term hydraulic cylinder locking, hydraulic cylinder load holding, hydraulic cylinder tensioning applications, the pressure in the system must be kept, although locking valves etc. are used in the system, the system pressure will drop due to leaks and the pump will need to be activated frequently. In such applications, accumulators slow down the drop 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 closure of valves, intermittent oil transfers due to the nature of the pumps, or the effect of an external force. Thanks to the damping to be made with the accumulator, the lifetime of all circuit elements will be extended.

It is also possible to use hydraulic accumulators in closed-circuit systems for the purpose of balancing the expansion caused by temperature 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 case of power failure, the hydraulic accumulator can be used to reduce the loads to zero position, to open or close the doors or covers at the completion of the cycle.

In the hydraulic circuit in the figure, the battery is charged when the 4/3 closed center direction control valve is in the middle position, the 2/2 valve opens and closes the battery line, the check valve in the pump line is used to prevent the pressurized oil in the battery from reversing the pump. The battery has a gold safety block. There is a safety valve and 2 ball valves in the block, one of the ball valves is used to connect the battery to the system, while the other is used to discharge the pressurized oil in the battery to the tank.

Hydraulic accumulators are placed between the valve and the cylinder when they are used to compensate for oil leaks or to balance the pressures that may occur due to thermal expansion or counterforce. The hydraulic accumulator using the circuit in the figure will prevent the pressure drop by compensating for the leaks that may occur in the 4/3 closed center direction control valve or the hydraulic cylinder. At the same time, the gas in the accumulator will be compressed in the counter forces coming from the outside to the cylinder, allowing oil to enter the accumulator, and the counter force will be balanced with a small pressure increase.