It is special for treating the used and old transformer oil, mutual inductor oil and switch oil. Comparing with the single-stage type, this machine adopts the double-stage vacuum system, which can improve the working vacuum value highly, so it dewater, degas and remove impurities more thoroughly. It can also inject the insulating oil into the transformer online, regenerate the seriously deteriorated oil by removing the polarity materials. This machine is specially applied to vacuum oiling and drying for power transmission equipment that are over 110KV.