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Time：2025-05-16 10:55:12 Reading volume：
Transformer oil vacuum purifier (also known as transformer oil vacuum oil filter) is a special equipment used to remove moisture, gas, impurities and trace solid particles from transformer oil. Its core principle is to restore the insulation performance and chemical stability of the oil by combining vacuum dehydration and degassing with precision filtration. The following is a detailed breakdown of its working principle:
(1) Vacuum dehydration and degassing
- Vacuum flash evaporation technology:
After the transformer oil is heated to 50~65℃ (to avoid high temperature oxidation), it is sprayed into a high vacuum (usually ≤0.1kPa) container. Under low pressure, the boiling point of the oil decreases, and the moisture and gas (such as oxygen and nitrogen) quickly vaporize and separate from the oil.
- Moisture removal: Water evaporates under vacuum and is pumped out by the vacuum pump.
- Gas removal: Dissolved gas is precipitated due to the sudden ｄｒｏｐ in pressure and discharged through the vacuum system.
- Thin film degassing technology:
Some equipment uses a thin film evaporator, and the oil forms a thin film flow under vacuum, which increases the vaporization surface area and improves the dehydration efficiency.
(2) Multi-stage precision filtration
- Mechanical filtration:
Solid particles, carbides and other impurities are intercepted through step-by-step filter elements (such as 10μm→5μm→1μm).
- Adsorption purification:
Silica gel or molecular sieve adsorption columns can be selected to remove soluble pollutants such as acidic substances and colloids.
| System module | Functional description |
|--------------------|----------------------------------------------------------------------------|
| Heating system | Electric heating or steam heating to control the oil temperature within a safe range (usually ≤65℃). |
| Vacuum separation system | Including vacuum tank, atomizing nozzle/thin film evaporator, creating a low-pressure environment to achieve vapor-liquid separation. |
| Filtration system | Multi-stage filter elements (metal mesh, fiber, polypropylene) intercept particulate matter. |
| Vacuum pump group | Roots pump + rotary vane pump combination to maintain high vacuum (residual pressure ≤50Pa). |
| Control system | PLC automatically adjusts temperature, vacuum degree, and flow rate to prevent overload or secondary contamination. |
1. Pretreatment:
Dirty oil is filtered through a coarse filter to remove large particles of impurities to protect subsequent equipment.
2. Heating:
The oil is heated to the set temperature through a heater (to improve water mobility).
3. Vacuum separation:
Hot oil is sprayed into the vacuum tank, water/gas evaporates, and dry oil sinks.
4. Fine filtration:
The oil passes through a precision filter element group to remove residual particles.
5. Output:
The purified oil is returned to the transformer or oil storage tank after passing the test.
- Oil quality standard after treatment:
- Water content: ≤5ppm (ultra-high voltage transformer requires ≤3ppm)
- Gas content: ≤0.1%
- Breakdown voltage: ≥60kV (IEC standard)
- Processing capacity:
Small machine (500L/h) to large machine (12000L/h) optional.
- Transformer maintenance:
New oil purification, operating oil regeneration, and oil treatment during maintenance.
- Fault recovery:
Emergency treatment of damp or slightly deteriorated oil (such as increased dielectric loss due to dampness).
- In conjunction with other processes:
Combined with oil chromatography analysis to ensure that the oil quality meets the GB/T 7595 or IEEE Std 637 standards.
The transformer oil treated by vacuum purification can significantly improve the insulation strength (breakdown voltage recovery rate reaches more than 95%) and extend the life of the equipment. It is key equipment for the preventive maintenance of power systems. In actual operation, the process parameters need to be adjusted according to the oil quality test report (such as micro-water, dielectric loss, chromatographic analysis).
