The oil for electric transmission and transformation equipment such as transformers, current transformers, voltage transformers, high-voltage switches can not be injected at a normal preesure. Usually these equipments are injected with insulating oil in vacuum conditions, so as to ensure their safe operation. However, with the changes of the season and the constant analytic sampling of the oil, the insulating oil in these equipments will evaporate, leak, contract or decrease, so that the oil may become less than required for electrified operation, and thus may bring about great hidden dangers to the safe operation of the equipment. The ZZ series vacuum oil injector is made on the basis of Yuneng's long-term experience in treating various kinds of high-purity transform oil and turbine oil. It can meet to the greatest extent, the needs of vacuum oil injection and supplementation of various types of electric transmission and transformation.