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Function and working principle of bellows accumulator
Release time:
2023-04-17
The function of a bellows accumulator is to: dampen vibrations, absorb shocks, compensate for leaks to maintain pressure, and serve as an auxiliary power source in systems where hydraulic cylinders only operate intermittently or for short periods. When the hydraulic cylinder is not working, the pressure oil discharged from the pump is stored for use during movement, thus allowing for the selection of a smaller pump.
Bellows Accumulator As the name suggests, it is a device that can store energy. Accumulators are used in hydraulic technology for the following purposes:
1. Functions of a Bellows Accumulator
1) Damping and absorbing shocks.
2) Compensating for leaks to maintain pressure.
3) Used as an auxiliary power source in systems where hydraulic cylinders only need intermittent or short-term operation. When the hydraulic cylinder is not working, the pressure oil discharged by the pump is stored for use during movement, thus selecting a smaller pump.
4) Energy recovery and reuse, which is particularly favored in the current focus on energy conservation and emission reduction.
Theoretically, the elasticity of a spring, or the potential or kinetic energy of a weight, can also be used to store energy. However, in modern times, due to high working pressure and high power, accumulators are needed to store and release a large amount of energy in a short time. Therefore, currently, only high-pressure gas is basically used for energy storage.
2. Working Principle of Bellows Accumulator
1) Working Process
The gas is compressed, and the pressure increases. The volume of a certain amount of gas is roughly inversely proportional to its pressure. The bellows accumulator utilizes this characteristic of gas.
The gas inside the bellows accumulator is generally pre-charged before use to reach the pre-charged gas pressure P0. At this time, the volume V0 of the gas is the volume of the accumulator.
When the hydraulic oil pressure is lower than P0, the accumulator cannot enter the accumulator at all, and the accumulator does not work. Hydraulic oil can only enter the accumulator when the pressure is higher than the gas pressure. As hydraulic oil enters the accumulator, the gas is compressed, and the pressure continues to rise.
Therefore, the pressure of the hydraulic oil also needs to increase accordingly to continue entering. The hydraulic oil pressure stops rising and cannot enter the accumulator anymore. The volume of hydraulic oil entering the accumulator will never reach the volume V0 of the accumulator. This is because it means that the gas volume is zero, and the gas pressure will be infinitely large.
The pressure of the gas and hydraulic oil is the stored energy. Once the oil port pressure drops, the gas will push the hydraulic oil out of the accumulator. After the hydraulic oil is completely squeezed out of the accumulator, the gas pressure will drop to P0.
2) Safety Standards
Considering the compressive strength and safety of the shell, any accumulator has a limit of allowable pressure P4.
Once the shell of a bellows accumulator breaks, it will explode. Therefore, it is a product that must be used cautiously. It must be produced and used strictly in accordance with relevant national and international standards. To avoid combustion, the gas used in the accumulator is usually nitrogen.
