Dehydration Principle Of Vacuum Transformer Oil Purifiers

Writer： Kaiqian Oil Purifier Release time：2025-11-03 16:51 Clicks：

Working Principle

 A vacuum oil purifier creates a high vacuum (extremely low pressure) environment. This allows the water in the oil to rapidly "boil," transforming from liquid to gas (water vapor) even at relatively low temperatures (typically 40-70°C). The dissolved and emulsified water is then "evaporated" and removed, separating it from the oil and achieving the desired dehydration.

Process

1. Pretreatment: Heating and Coarse Filtration

Heating: The transformer oil to be treated first passes through a heater, where it is uniformly heated to 50-70°C. Heating serves three purposes:

• Reducing the oil's viscosity: This improves its fluidity, facilitating subsequent handling and allowing water to escape.
• Increasing the kinetic energy of water molecules: This allows them to overcome surface tension and escape from the oil more easily.
• Providing latent heat of vaporization: Providing the necessary energy for water to transform from liquid to gas.
• Coarse Filtration: The oil first passes through one or more filters to remove solid particles, impurities, and fibers, thereby preventing them from clogging the subsequent fine filter and damaging the vacuum pump.

2. Core Process: Vacuum Degassing and Dehydration

• Atomization: The preheated and coarsely filtered oil is fed into a distributor (usually a spray device or packing layer) at the top of the vacuum tank. This device disperses the oil into extremely fine droplets (atomization) or forms a thin oil film. This increases the surface area of contact between the oil and the vacuum, accelerating water evaporation.
• High-Vacuum Environment: The vacuum tank is evacuated to a very high vacuum level (usually hundreds of Pa or even tens of Pa absolute) using a vacuum pump. Under this extremely low pressure, the boiling point of water dissolved in the oil and water in an emulsified state becomes very low.
• Water Evaporation and Separation: Under the combined effects of low pressure and heat, the water in the oil rapidly vaporizes, forming water vapor, which escapes from the oil.
• Gas Discharge: Escaping water vapor and non-condensable gases (such as air, acetylene, and hydrogen) are continuously extracted from the top of the vacuum tank by a vacuum pump.
• A condenser is typically connected to the vacuum pump outlet to condense the extracted high-temperature water vapor into liquid water, which is collected in a water storage tank. This protects the vacuum pump and facilitates monitoring of the dehydration results.

3. Post-Processing: Fine Filtration and Output

• Process: Clean oil after vacuum dehydration and degassing accumulates at the bottom of the vacuum tank and is extracted by an oil drain pump.
• Fine Filtration: After the oil drain pump, the oil passes through a fine filter (sometimes a safety filter) to remove extremely fine particles that may have been generated or carried over from the vacuum tank, ensuring high oil cleanliness.
• Output: Ultimately, clean, dry, and pure transformer oil is returned to the transformer or a clean oil storage tank.