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Time：2025-08-22 13:50:44 Reading volume：
There's no fixed value for the dehydration rate of a vacuum oil filter. Unlike flow rate, which is a constant parameter, it's a performance indicator influenced by a variety of factors.
This article illustrates typical industry ranges and values from some top-tier equipment, but it's more important to understand the factors that influence it.
Typical Dehydration Rate Range
Common/Economy Vacuum Oil Filters: Dehydration capacity is approximately 1-3 kg/hour.
Standard Industrial-Grade Vacuum Oil Filters (the most common type): Dehydration capacity typically ranges from 5 to 15 kg/hour.
High-Performance/Large-Scale Professional Vacuum Oil Filters: Dehydration capacity can reach 20-40 kg/hour or even higher, and they are designed specifically for handling severe water ingress in large transformers or for rapid maintenance.
Note: Many equipment nameplates or manuals may not directly indicate "dehydration rate" because it is measured under specific conditions.
Dehydration rate depends on the overall performance of the system and is primarily influenced by the following factors:
Ultimate Vacuum: The higher the vacuum, the lower the boiling point of water. Under high vacuum, water in the oil "boils" and evaporates at a relatively low temperature, allowing it to be extracted by the vacuum pump. The dehydration efficiency of equipment with an ultimate vacuum of only -95 kPa differs significantly from that of equipment capable of reaching -99.9 kPa.
Vacuum Pump Speed: A vacuum pump must not only be able to achieve a high vacuum but also be able to quickly extract large amounts of water vapor. Therefore, high-performance oil purifiers typically use a "Roots pump + rotary vane pump" combination. Roots pumps are extremely efficient at high flow rates, while rotary vane pumps can maintain a high vacuum.
Principle: Heating reduces the viscosity of the oil, making it easier for water to separate and move, while also providing energy for the vaporization of water molecules.
Control and Balance: Higher temperature is not always better. Excessively high temperatures (typically exceeding 65-70°C) can cause thermal aging (cracking) of the insulating oil, generating acids and sludge that can contaminate the oil. Therefore, uniform and controlled heating is crucial.
Principle: Dehydration occurs within the vacuum tank. The oil is sprayed or spread into a large-surface film, or flows through high-efficiency packing (such as Raschig or Pall rings) to maximize the contact area between the oil and the vacuum.
Design Differences: The dehydration efficiency of a simple vacuum tank and a vacuum tower equipped with high-efficiency degassing packing and a very large surface area can differ significantly. The latter has a larger evaporation surface area, significantly increasing the dehydration rate.
Water removal from very wet oil (for example, from 50 ppm to 20 ppm) is relatively easy, but the dehydration rate may appear high. However, as the oil approaches a dry state (for example, from 10 ppm to 5 ppm), removing the last traces of deeply dissolved water becomes extremely difficult, and the dehydration rate drops sharply. It's like trying to soak up water on the floor with a towel: it works quickly at first, but becomes increasingly difficult to wring out over time.
The dehydration rate of a vacuum oil filter is a variable. A well-designed, high-end unit (with high vacuum, efficient heating, and a large surface area degassing tower) can achieve an instantaneous dehydration rate of over 20-30 kg/h when treating oil with a high water content.
However, buyers shouldn't be overly concerned with theoretical maximums. Instead, they should focus on whether the unit can safely and effectively treat the oil to your desired final standard (e.g., a water content of < 5 ppm) without damaging the oil, and whether its core components (vacuum pump, heater) are robust.
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