Series ZYD Double-stage-vacuum transformer oil purifier can completely and quickly remove water, trace water, gas, particles as well as other harmful ingredients from oil to improve oil's dielectric strength, effectively making sure electric equipments working safely and normally. Series ZYD vacuum oil purifier is particularly suitable for treating high-grade transformer oil, super-voltage transformer oil and new transformer oil. It can be used for filtration of more than 110V substation live line work onsite. Meanwhile, Series ZYD oil purifier can be used as independent vacuum source with functions of vacuum drying and vacuum oiling.