Can the transformer oil purifier filter other oils?

When it comes to oil purification, many people wonder if transformer oil purifiers (also known as vacuum oil purifiers or insulating oil purifiers) can be used for other oil types. The short answer is yes, but only for certain oil types. Unintentional use can damage equipment, cause contamination, and even pose a safety hazard.

Suitable Oils for Transformer Oil Purifiers

Transformer/Insulating Oil

These purifiers are designed for exactly this purpose—removing moisture, gases, and solid particles to maintain dielectric strength.

Turbine Oil

Mineral-based turbine oils also offer the advantages of dehydration and fine filtration, making transformer oil purifiers an ideal choice.

Mineral Hydraulic Fluids (HM, HV Types)

Transformer oil purifiers perform exceptionally well in systems where water and solid particles are primarily a concern.

Sometimes Suitable: Gear oils and machine oils can be filtered, but due to their higher viscosity and additives, they require preheating and careful monitoring.

Oils to Avoid

Synthetic Oils (such as Phosphate Ester or SKYDROL)

These oils can react with seals and coatings, corrode the oil purifier, and damage the oil and equipment.

Engine Oil

Engine oil contains additives and is therefore not suitable for vacuum heating—this can cause additive breakdown and oil instability.

Brake Fluid and Fuel

They have low flash points and high reactivity, posing serious safety risks.

Edible Oil or Biodegradable Oil

These have completely different chemical properties and are incompatible with standard transformer oil purifiers.

Best Practices Before Filtering

Use specialized equipment for each oil type whenever possible.

If you are unsure of oil compatibility, consult the manufacturer.

When switching between different mineral oils, thoroughly flush the filtration system to prevent cross-contamination.

Summary

Transformer oil purifiers are very effective for transformer oil, turbine oil, and mineral-based hydraulic fluids. However, if synthetic engine oil or specialty fluids are involved, discontinue use immediately and use a system designed for these fluids.

Rule of thumb: If it's mineral oil, it's generally safe; if it's synthetic or specialty oil, avoid it.