What are the main
types of bellows accumulators?
1. Hammer accumulator
The hammer accumulator stores and releases energy by changing the position of the heavy hammer to the north. The heavy hammer exerts a certain pressure on the hydraulic fluid through the plunger. The accumulator has the advantages of simple structure, hidden pressure, small capacity, low pressure, large size, heavy weight, large inertia and insensitive response, so it is often used in the hydraulic system of large fixed equipment.
2. Bellows accumulator
Bellows accumulators use springs to store and release energy. The spring force acts on the hydraulic oil through the piston. The oil pressure depends on the preload of the spring and the area of the piston. This accumulator is characterized by simple structure and sensitive response, but small capacity, not suitable for high pressure or high cycle frequency.
3. Air accumulator
The accumulator uses the compression and expansion of a sealed gas to store and release energy. Generally use inert gas or nitrogen as filling gas, commonly used are piston type and bag type.
Bellows accumulator types are mainly divided into spring type and inflatable type.
Accumulator function, short-term large amount of oil supply, system pressure, emergency energy, relieve the impact pressure, absorb pulsating pressure.
The functions of bellows accumulators fall into four main categories: energy storage, hydraulic shock absorption, pulsation elimination and energy recovery.
One: energy storage. This function can be subdivided into: as an auxiliary power source, it can reduce installed capacity, compensate leakage, compensate thermal expansion, and as an emergency power source, it forms a constant pressure oil source.
Second class: absorb hydraulic shock. The sudden reversing of the reversing valve and the sudden stop of the actuator movement will produce pressure impact in the hydraulic system, so that the system pressure rises rapidly in a short time, causing damage to the instrument, components and sealing device, as well as vibration and noise. In order to ensure the absorption effect, the accumulator should be set near the impact point, so the accumulator is generally installed in front of the control valve or hydraulic cylinder and other impact sources, which can well absorb and buffer the hydraulic impact.
Three categories: eliminating pulsation and reducing noise. For hydraulic systems with plunger pumps and fewer plungers, periodic changes in pump flow cause the system to vibrate. The accumulator can absorb a large amount of energy in the pulsating pressure and flow rate, and within one cycle of the flow pulsation. Part of the oil with instantaneous flow higher than the average flow is absorbed by the accumulator, and part of the oil with lower than the average flow is supplemented by the accumulator, which absorbs the energy in the pulsation, reduces the pulsation, and reduces the damage to the sensitive instrument and equipment.
Four categories: Energy recovery. Accumulator energy recovery is a research field at present. Energy recovery can improve the energy utilization rate and is an important way to save energy. Because the accumulator stores energy temporarily, it can be used to recover potential energy from a variety of functions and locations. The main research in this aspect includes: recovery of braking energy of vehicles, recovery of potential energy of construction machinery boom mechanism, recovery of braking energy of rotary table of hydraulic excavator, recovery of gravitational potential energy of oil workover rig and drilling rig oil pipe falling, recovery of gravitational potential energy of lifting truck descending.
