Modern pneumatic and hydraulic accumulators are specialized devices for the accumulation and subsequent delivery of hydraulic energy in hydraulic systems.
Very often they are sometimes called hydroaccumulators, but it is still a more common name for vessels with pressure dividers. For example, hydrophores and expansomas are also included in the category of hydrocarbons.
Almost everywhere, where hydraulic systems are used, at least one hydro accumulator can be found. The fact is that, despite the relative simplicity of the design of these devices, their integration into the hydraulic system allows you to solve a number of critical tasks right away. Let's examine in more detail some of them.
1) Improved reliability of the hydrosystem
During the operation of the hydraulic system at one or another frequency for various reasons there are splashes of pressure of the working hydraulic fluid. But the liquid is practically not compressed, therefore, in the absence of a compensator in the form of a pneumohydraulic accumulator, leakage of fluid from the seals (for example, in hydraulic cylinders) begins to occur. In addition, there may be a system depressurization due to damage to high pressure hoses, pipelines and other components. And in the presence of installed in the right place of the hydroaccumulator is smoothing of peak pressure, which occurs due to the receipt of excess fluid inside its working cavity.
Figure 1 - Hydraulic accumulator in the hydraulic station
Hydraulic equipment is not subject to increased loads due to hydraulic shock. At the same time, the gas (which is usually nitrogen), located on the medium separator, is compressed, and the separator itself shifts. Depending on the structure of pneumohydroaccumulators such separators may be:
- Membrane - usually used where it is necessary to have the fastest response to change in pressure in the system. Membrane hydroaccumulators have relatively small volumes, very common in mobile technology.
- Elastic cylinder - used in balloon hydroaccumulators, very common in the industry.
- Piston - used in piston industrial pneumatic accumulators. Piston hydraulic accumulators are characterized by large volumes and high reliability. Used almost exclusively in industry.
- A metal bellows is a delimiter in bellows hydraulic accumulators. Used mainly on large sea vessels.
2) Removal of cavitation phenomena of piston pumps
In modern industry and powerful mobile technology, high pressure piston pumps are often used. Due to the peculiarities of the design of these pumps, they may have cavitation phenomena, which are manifested in increasing their vibration, noise and reduction of feed. All this can have a very negative impact on both the performance of the system and its reliability.
The hydraulic accumulator installed in one hydraulic line before the piston pump allows to significantly improve the efficiency of the pump. During the cycle of work there is a collection of fluid from the system (peak levels of pressure), as well as the return of the fluid back to the hydraulic system when there is a drop in pressure. Examples of such devices are bellows hydraulic accumulators firm HYDAC for diesel engines of large sea-going vessels.
3) Lowering the noise level
Noise in the operation of the hydrosystem can cause not only the discomfort of people who are nearby, but also serve as an indicator of incorrect operation of some of its nodes. In this case, the competent use of pneumohydroaccumulators can often solve both problems - and reduce the noise to the normal level, and make the whole hydraulic system work more correct.
4) Accumulation of significant volumes of hydraulic energy
During the work of large industrial hydraulic presses, there is often a need for the gradual accumulation of hydraulic energy in large volumes for the further release of this energy. For such purposes, several tens of hydrocarbons can be used at once.
And it's worth remembering that pneumohydraulic accumulators can operate at very high pressures that are not safe for health and even human life. Therefore, ensuring the proper functioning and maintenance of hydraulic accumulators and their varieties (for example, hydraulic damper) is a task of professional servicing engineers.