Do Oil Purifiers Have Vacuum Dehydration?

Principles, Core Functions, and Applications

Oil purifiers—also known as oil filtration or purification systems—generally include vacuum dehydration, which is one of their most important core functions.

Vacuum dehydration is a high-efficiency physical oil treatment method, especially suitable for moisture-sensitive oils such as turbine oil, transformer insulating oil, and hydraulic oil, where extremely low water content is required.

Working Principle of Vacuum Dehydration Oil Purifiers

Vacuum oil purifiers remove water, gas, and contaminants through a controlled multi-stage process:

1. Heating

Oil is gently heated to 60–70 °C to reduce viscosity and increase water vapor pressure while preventing oil aging.

2. Atomization / Thin-Film Formation

The heated oil enters a vacuum separator and is atomized into fine droplets or spread into a thin film, greatly increasing surface area.

3. Vacuum Evaporation

Under high vacuum (e.g., −0.095 MPa), the boiling point of water drops to around 40 °C, allowing free, emulsified, and dissolved water to rapidly vaporize.

4. Gas–Liquid Separation

Water vapor and non-condensable gases are extracted by the vacuum system, condensed, and discharged.

5. Precision Filtration

The dehydrated oil passes through high-precision filters (1–5 µm) to remove solid particles and colloidal impurities.

6. Clean Oil Output

Purified oil is returned to the system or stored for reuse.

Three Core Functions of Oil Purifiers

A vacuum oil purifier integrates multiple purification functions:

Water Removal (Primary): Efficiently removes free, emulsified, and dissolved water.

Degassing (Secondary): Extracts dissolved gases such as air and hydrogen, reducing oxidation and performance loss.

Impurity Removal (Basic): Multi-stage filtration removes solid contaminants and metal particles.

Typical Application Scenarios

Turbine Oil Systems: Prevents emulsification and protects bearings during online or bypass operation.

Transformer Insulating Oil: Essential for moisture and gas control during maintenance and oil filling.

Hydraulic Systems: Improves cleanliness and reduces valve wear and sticking.

Lubricating Oil Regeneration: Extends oil life and lowers operating costs.

Oil Purifiers Without Vacuum Dehydration

Not all oil purifiers remove dissolved water:

Plate and Frame Filters: Remove solids and limited free water only.

Centrifugal Oil Purifiers: Effective for free water but poor at dissolved moisture removal.

Coalescing Oil Purifiers: Excellent for free water and emulsions, less effective for dissolved water.

Conclusion

Vacuum oil purifiers provide the most effective dehydration performance, particularly for turbine oil and transformer insulating oil. In most industrial applications, the term oil purifier refers to a vacuum oil purification system combining heating, vacuum separation, degassing, and precision filtration.

When selecting equipment, vacuum dehydration capacity and water removal efficiency are among the most critical performance parameters.