... screens with mesh size reduced stage by stage. The filtration precision gets to international standard; NAS 4 Class . ... . Series IIJ-II Zhongneng Automatic Insulating Oil Tester (oil filtration, oil purification, oil treatment, oil purifier, oil recycling, ... oil reconstituted, oil restituting, oil recovering, oil recondition, oil filters, oil refinery, oil refiner, oil cleaning, oil recycle, oil ...