Working principle of energy accumulator
Hydraulic oil is an incompressible liquid, so it is not possible to accumulate pressure energy using hydraulic oil, and it needs to rely on other media to convert and accumulate pressure energy. For example, the bladder type inflatable accumulator developed by using the compressibility of gas (nitrogen) is a device for storing hydraulic oil. The bladder type accumulator consists of an oil part and a gas part with a gas seal, and the oil around the bladder is connected to the oil circuit. When the pressure increases, the oil enters the accumulator and the gas is compressed until the system pipeline pressure no longer increases; When the pipeline pressure drops, compressed air expands, hydraulically injecting oil into the circuit, thereby slowing down the decrease in pipeline pressure.
The purpose of the accumulator
Accumulators have two purposes. ① When the flow required by the load during low-speed movement is less than the flow rate of the hydraulic pump, the excess flow rate of the hydraulic pump is stored in the accumulator. When the flow rate required by the load is greater than the flow rate of the hydraulic pump, the liquid is discharged from the accumulator to compensate for the insufficient flow rate of the hydraulic pump When the machine is shut down but still needs to maintain a certain pressure, the hydraulic pump can be stopped and the accumulator can compensate for the leakage of the system to maintain the pressure of the system. Accumulators can also be used to absorb the pressure pulsation of hydraulic pumps or the hydraulic impact pressure generated in the system. The pressure in an accumulator can be generated by compressed gas, heavy hammer, or spring, and the accumulator can be divided into gas type, heavy hammer type, and spring type accordingly. The direct contact between gas and liquid in gas accumulators is called contact type, which has a simple structure and large capacity, but gas is easily mixed in the liquid, and is commonly used in hydraulic presses. Gas and liquid that do not come into contact with each other is called an isolation type, which is commonly isolated by a skin bag and a diaphragm. The volume change of the skin bag is large, while the volume change of the diaphragm is small, and it is commonly used to absorb pressure pulsations. The heavy hammer type has a large capacity and is commonly used in systems such as rolling mills for energy storage.