While operating hydraulic equipment, a schedule of operating liquid analysis must be established. Another important point is to define all potential weak spots where contamination may enter the system. Dissemination of operating liquid analysis results in various stages of operation allows to promptly respond and improve filtration of the liquid, maintaining efficiency of the machinery.
Contamination is especially dangerous to hydraulic systems because it is not directly visible by the naked eye. The danger of the seemingly harmless components should be clearly understood.
In most cases the solid particles which can damage hydraulic systems are smaller than 10 micron, while the naked eye can only see particles 40 micron and larger.
Each facility should maintain a professional whose responsibility is to monitor the condition of operating liquid. Specifically, such person should be responsible for the following:
1) sampling of supplied liquid from the manufacturer
2) analysis of such sample for presence of contaminants using special lab equipment
3) knowledge of the purity requirements
4) ability to correctly introduce the liquid into the hydraulic system
5) understanding of causes of contamination and knowledge of point where contaminants may enter the hydraulic system.
In general, 70 to 80% of hydraulic system failures are caused by contamination.
Understanding of the origins of contamination can prevent such failures.
Liquid received from the manufacturer must comply with certain requirements. It must be transported in clean vessels. However, the vessel does not have to comply with the purity of the whole hydraulic system. Therefore, the liquid must never be filled into the system directly from the transportation vessel.
Liquid enters the system through a special pump with a filter. At least 10 micron filtration is required.
A significant portion of the contamination may originate from the high pressure hoses or pipes, if those are not rinsed during replacement of the fluid. Even if the system is equipped with a filter, components wear and contaminants may enter sensitive parts of the system on the way to filter. Thorough filtration may help to reduce the contamination significantly, but it cannot eliminate the contamination entirely.
If a part fails in the hydraulic system, it must be replaced. Before replacement, the external surface around that part must be thoroughly cleaned. It should also be remembered, that no hydraulic system will fail if the hydraulic fluid complies with the required purity standards.
The most sensitive component of the hydraulic system is, perhaps, the axial-piston pump with wobbler plate. It can let through particles with size of less than 10 micron. Contamination may cause pumps to fail.
Hydraulic motor manufacturer are also responsible for the quality of their products, reducing the risk of contamination while installing and operating their product to the minimum.
The required purity of hydraulic fluid is determined based on the sensitivity of the system’s components to contamination, system pressure and ambient conditions.
In practice, the degree of contamination is determined by measuring the size and number of solid particles in 100 milliliters of hydraulic fluid. The results are checked against the charts in ISO 4406 standard.
If the purity of the liquid does not comply with the standards, special equipment should be used. GlobeCore produces UVR units for purification (regeneration) of turbine, industrial and transformer oils. It can also lighten heavy fuel oil, gas condensate, dark diesel fuel, gasoline etc.
This equipment can be supplied to any facility. The UVR type plants do not require special placement, emits no noise and is simple to transport anywhere in the world.
After purification of the hydraulic liquid with the UVR system, you can be confident that it will serve well throughout its lifetime and will not fail due to contamination of various origins.
