Insulating oil performance mainly decided by oils water content, If the water is not saturation in the oil, it appears as the molecular states; If water is saturation in the oil, it appears as the liquid states and stay at the bottom of container. Under the vacuum states, because the less gas content, the water and gas in the oil will be escaped from the oil and evacuated by the vacuum pump. The higher vacuum value (Close to 0 Pa), the higher speed of water molecular volatilization (The latest technology, the Vacuum oil purifier can reach to 1Pa Working vacuum value). The gas and water which dissolved in the oil will become gaseity and exhausted by vacuum pump. The oil temperature affect vacuum oil purifier working efficiency, the higher temperature, the water molecular get more kinetic energy, so it is higher diffused speed of water molecular. But, exorbitant temperature will cause fracture of carbon chain for oil molecular, if that will make oil bad. So we don’t suggest the oil temperature excess value="80" tcsc="0" unitname="C" w:st="on">80C. Also the impurity will affect oil dielectric strength, so the vacuum oil purifier requires high filtration precision.