Globecore insulating oil clarification systems with Fuller’s Earth

Insulating oil, or, in other words, transformer oil, is a mineral based organic compound, which is usually used in transformers because of its chemical properties and dielectric strength. Since it is a cooling agent and insulating medium that protects your insulation paper, its functions are essential for proper transformer operation.

Your transformer oil purifier is no longer helping you with your used insulating oil? That’s no surprise. At some stage of your transformer life, around 15-20 years of transformer operation, oil purification is no longer effective. In this case you can replace the oil (which is a very common option) or use an insulating oil clarification system to regenerate it – which is a BETTER option.

Insulating oil clarification systems with Fullers Earth provide a regeneration process that offers the following benefits:

  • Removes sludge and oxidation byproducts
  • Lowers the acid number
  • Clarifies the oil
  • Restores interfacial tension
  • Improves dissipation factor
  • Equipment is easy to mount and operate
  • Compatible with other transformer oil purification equipment of any capacity
  • Extends useful life of insulating oil

Globecore insulating oil clarification systems are filled with Fullers Earth. This is naturally occurring sorbent clay that easily adsorbs impurities from the oil. Thanks to its crystalline structure it can absorb large amounts of acidity and 25% of water.

The main advantage of application of Fullers Earth in insulating oil clarification systems is its high porosity – up to 125 m²/gram, this feature provides high level of adsorption of contaminants from oil.

Globecore insulating oil clarification systems with Fullers Earth are designed to provide the best solution for your company. The main elements of the system are: two tanks filled with Fullers Earth, filter, pallet collar. Each tank is a metallic cylinder with a hatch in the bottom, the top is closed by a lid.

There is a push button at the top of the vessel which serves to provide required density for the bulk material. The vessels are held upright by fixing devices. The cylinders may be turned over if the Fuller’s earth needs to be replaced. In the upper part there is a valve that keeps the material condensed. Tanks are maintained in vertical position by restrainers.

Average oil appearance

transformer oil before and after regeneration

Transformer oil before and after purification



Trial pattern

Before regeneration

After regeneration


Deemed by eye exploiting crossing light and room temperature for 100 mm thick oil

Turbid  brown fluid

Transparent sedimentless fluid to lack weighed particles

Acid number, mg КОН/g

IEC 296; ASTM D-664



Corroding sulfur

ISO 5662; ASTM D-1275



Breakdown voltage, kV

IEC 156; ASTM D-1816



Dielectric loss tangent for 90ºС

IEC 247; ASTM D-924



Interfacial tension, N/m, for 25ºС

ISO 6295; ASTM D-2285



Solid contaminants size, micron



Oxidizing stability:

Acid number, mg КОН/g

IEC 1125А; IEC 1125B; IP-307


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