Hydraulic Accumulator is an energy storage device which is filled with pressurized fluid that supplied constant pressure to hydraulic system. Fluid is pumped by the hydraulic pump and enters into the accumulator and starts charging as the nitrogen in the bladder is compressed via fluid pressure is greater than the pre-charged pressure. When pump can’t supply constant pressure in any sudden case the accumulator can supply instant pressure for smooth pulsation.
Generally, accumulator is separated between compressible gas and non-compressible fluid inside the shell. The bladder pre-charged with nitrogen gas and pressure calculated by system requirement.
Hydraulic accumulator has three separate part according to construction
- Hydraulic fluid/oil chamber
- Compressed gas/Oil chamber
In a spring type accumulator spring forces to piston and it acts against the fluid. Spring supply the require pressure to the system if needed. Spring accumulator is used to mobile applications for their small in size. There are some disadvantages of spring accumulators. Its cycle rates is very high and spring may lose their elasticity.
2.Raised weight accumulator
Raised weight accumulator constructed with a cylinder and fluid filled inside it. A series of weights kept on it and exerts a downstream force to the piston resulting pressure and thus delivery the constant pressure. This type of accumulator has used in the tower, bridge London.
Piston accumulator is consist of cylinder assembly and fluid and gas is separated with piston. When fluid enters inside the cylinder then piston acts to upstream forces to gas and it get compressed and when system needs instant pressure piston forces downstream pressure and supplied needed pressure to the system. Usually piston accumulator uses due to their greater efficiency and flexibility and can operate in high temperature fluids. Mounting is very easy and long life time and require less maintenance. On the other hand, it is very expensive to manufacture.
Bladder accumulator is a kind of hydro-pneumatic accumulator. This type of accumulator is filled with nitrogen gas and fit inside the steel pressure vessel. Typically, bladder accumulator is use to both low- and high-pressure applications. This type of accumulator can response time is fast.
5.Compressed gas accumulator
This type of accumulator have a cylinder inside and an elastic diaphragm separate this two chamber between fluid and gas. Fluid chamber is connected with hydraulic line and other chamber hold gas under pressure.
Diaphragm accumulator is used in both industrial and mobile applications. A synthetic rubber diaphragm that separate with the gas and liquid chambers. Its main advantages are Compaq design, low cost and quick shock response type.
Mobile hydraulics and industrial machinery.
- Relatively low installation cost
- Reduce hydraulic system shocks
- Quick response to hydraulic system for constant flow (As an example piston pumps create pulsating flow)
- Reduce the noise levels and shock absorption
- Maintain constant pressure