Hydraulic Accumulators
A hydraulic accumulator is a pressure storage reservoir in which a non-compressible hydraulic fluid is held under pressure that is applied by an external source. The external force could be a spring, a raised weight, or a compressed gas. An accumulator acts as a temporary storage system as it stores energy when pressure is applied to the hydraulic fluid and releases it again when the external pressure is released.
In many hydraulic applications, hydraulic pumps provide power that is often used in a cyclic fashion. This means that the pump needs to be continually switched from one to the other when power is required and unused fluid is returned to the reservoir. This switching often takes time and causes periodic surges in the system as the pressure from the pump increases and decreases. An accumulator is designed to buffer these changes in pressure and provide a steady flow of fluid.
The most common use of a hydraulic accumulator is in shock absorbers. In these applications, a standardized industrial accumulator is often used. In a typical shock absorber, a cylinder is filled with oil and gas, typically nitrogen, to buffer the compression and expansion of the piston as it moves along its travel path. The nitrogen gas adds stiffness and resistance to the movement making the suspension more stable and responsive.
Accumulators are also used in braking systems as part of the anti-lock brakes. In these applications, accumulators are used to provide a high-pressure source to quickly lock the brakes when activated. Accumulators also serve as a buffer to dampen the fluid pressure as the brakes are released. Another important application of accumulators is in hydraulic presses. These are heavy presses which need to press starts and stops precisely, and without hydraulic accumulators, the hydraulic pressure would spike, leading to uneven compression or even mechanical shocks.
Accumulators can also be found in smaller hydraulic equipment such as power steering and suspension systems where the accumulator is used to dampen pressure variation and provide for smoother, more precise operation.
The accumulator has a very important job and it is important to ensure that it is properly sized and maintained for the particular application. The ability of the accumulator to act as a shock absorber and provide a large degree of dampening is directly related to the condition, size and type of the accumulator. If the accumulator is too small, it will not be able to absorb all the pressure variations and cause the system to lag and become unreliable. On the other hand, a too large accumulator will cause the system to become sluggish and use more energy than necessary. As with many other hydraulic components, the accumulator plays an important part in ensuring that all the components work together, resulting in a reliable and efficient system.
In conclusion, hydraulic accumulators are an important part of any hydraulic system and play an important role in dampening pressure variation and providing reliable operation. They can be found in most industrial hydraulic systems, and should be sized and maintained appropriately. Failure to do so can lead to severe damage to the hydraulic system and loss of efficiency.
