With the higher cost for oils and ever increasing environmental regulation and liability, it is no longer economical to replace electrical insulating oils to renew their dielectric strength. Restoring these oils to their original strength through purification is now a necessity. High Vacuum Oil Purification Systems are designed specifically to meet the operational, economic and environmental needs of industry in purifying insulating oils. Through proven dehydration, degasification, and filtration techniques, the Hi-Vacuum Oil Purification Systems quickly and easily remove:

-	Removes free and emulsified water to less than 10 ppm
-	Free and dissolved air and gases to 0.25% of total gas content
-	Removes varnishes, paints, acids, resins, and oxidized agents and particulate matter

There are two types vacuum dehydrators; both function at elevated temperature. In one method the treatment is accomplished by spraying the oil into a vacuum chamber; in the other the oil flows in thin layers over a series of baffles inside a vacuum chamber. In both types the objectives is to expose maximum surface and minimum thickness of oil to the vacuum.

Filters
These are generally based on the principle of forcing oil under pressure through absorbing material such as paper or other filter media. Filters of this type are preferentially used in removing contaminants in suspension (The filter medium should be capable of removing particles larger than a nominal 10 micro m) These devices do not de-gas the oil.

The water-removing ability of a filter is dependent upon the dryness and quantity of the filter medium. When filtering oil containing water, the water content of the filter medium rapidly comes into equilibrium with water content of oil. A continuous indication of the water content of the out going oil is useful to monitor the efficiency of the process.

Care should be taken that paper filters are of the correct grade to ensure that they shed no fibers.