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Transformer Oil Purifier / Degasification (EHV)

The most important applications of high vacuum degasifiers are in the field of extra high voltage transmission and in the manufacture of electrical apparatus for it. In addition, the high vacuum process is used in the degasification of cable oils including polybutenes. Outside of the electrical industry, this process is used for dehydration and degasification of oils for radar and electronic equipment, vacuum pump sealing oils, brake fluids, refrigeration oils—including phosphate esters and silicones.


Enervac offers the EHV Vacuum Oil-Purifier series designed for maximum efficiency in your operations…performance tested by experts, requiring minimum maintenance, and providing long, trouble-free service.


Backed by the full resources of Enervac’s technical specialists, plus “knowhow” and thorough research, your Vacuum Oil-Purifier is unique. Designed for unattended operation and suitable for operation on energized equipment—complete monitoring equipment is also available.

Transformer Oil Purifier / Degasification (EHV)

Description of Process:

Oil is introduced into the vacuum chamber, where water, dissolved air and gases, and other low-boiling-range volatile contaminants are removed. Special chemically inert accelerator cartridges in the vacuum chamber are employed to serve the following functions:

  1. First, their in-depth design structure allows free water to be rapidly separated from oil by coalescence even before it reaches the evaporation stage.

  2. Second, millions of glass fibers 3-10 micrometer diameter provides a large total surface area for exposure of the thin oil film to the vacuum.

  3. Third, sharp points of the glass fibers promote fast release of gases and vapors from oil.

  4. Fourth, the elements act as a fine filter removing solid contaminants. The cartridges are easily replaced and disposable.

Transformer Oil Purifier / Degasification (EHV) Cargo Trailer Mount Option.jpg

This method is more efficient than previously used spray nozzles and baffles which required several passes to obtain the same degree of degasification.


  • Dehydration—at minimum oil temperatures of 27°C the water removal is from 50 ppm to less than 5 ppm.

  • Degasification—reduce soluble air content from full saturation of approximately 12% to less than 0.25%.

  • Particulate matter—standard after-filter provides filtration down to 0.5 micron

  • Other contaminants such as products of oil oxidation, thermal degradation, dissolved varnishes, paints and acids can be removed by the addition of optional Fullers Earth filters to the system.

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