The main functions and precautions of accumulators in hydraulic systems


1. The function of the accumulator


The accumulator can provide liquid with a certain pressure to the system in a short time, and can also absorb the pressure pulsation of the system and reduce the pressure shock. Its functions mainly include the following aspects.


The system maintains pressure. When the actuator stops working for a long time and needs to maintain a certain pressure, the hydraulic oil stored in the accumulator can be used to make up for the leakage of the system, so as to keep the pressure of the working chamber of the actuator constant. At this time, it not only reduces energy consumption, but also unloads the hydraulic pump to prolong its service life.


Absorb pressure shock and pulsation. Hydraulic shocks will occur when the control valve changes direction quickly, suddenly closes or the movement of the actuator suddenly stops. When the gear pump, plunger pump, relief valve and other components work, the system will also produce pressure and flow pulsation changes. In severe cases It can also cause malfunctions. Therefore, when the working stability of the hydraulic system is required to be high, an accumulator can be installed near the shock source and the pulsation source to alleviate the shock and absorb the pulsation.


As an auxiliary power source. When the actuator moves intermittently or only for a short time at high speed, the accumulator can be used to store pressure oil when the actuator is not working; when the actuator needs to move quickly, the accumulator and the hydraulic pump can supply the hydraulic cylinder at the same time pressure oil. In this way, a pump with a smaller flow rate can be used to obtain a faster speed for the moving parts, which not only reduces power loss, but also reduces the temperature rise of the system.


Used as an emergency oil source. When the power supply is interrupted suddenly or the hydraulic pump fails, the accumulator can release the stored pressure oil so that the actuator can continue to complete the necessary actions and avoid failures that may be caused by lack of oil.


Used as a hydraulic pump. When transporting special liquids that are corrosive to pumps and valves or are toxic and harmful, accumulators can be used as power sources to suck or discharge liquids.



2. Installation and use of accumulator


The accumulator is a pressure vessel. When handling and disassembling, the inflation valve should be opened to discharge the charged gas to avoid accidents due to vibration or collision.


The oil port of the accumulator should be installed vertically downward, and there should be a firm fixing device.


Inert gas (generally nitrogen) should be used in the airbag accumulator. Oxygen is absolutely prohibited in the accumulator, so as not to cause an explosion.


Welding, riveting and machining cannot be performed on the accumulator.


The accumulator cannot be disassembled in the oil-filled state.


A one-way valve should be installed between the hydraulic pump and the accumulator to prevent the hydraulic oil in the accumulator from flowing back into the hydraulic pump when the hydraulic pump stops working; a stop valve should be installed at the connection between the accumulator and the hydraulic system , for inflation, adjustment or maintenance.


The charging pressure of the accumulator should be 90% to 25% of the minimum working pressure of the hydraulic system; the capacity of the accumulator can be determined according to its use, and can be determined by referring to the relevant hydraulic system design manual.


The accumulator is a pressure vessel, which must have a production license to produce, so generally do not design and manufacture accumulators by yourself, but choose the finalized products of professional manufacturers.