for vacuum oil filtering machine and filtering by cartridge filter element and vacuuming degasing Roots pump is the main pump, ... used in large speed pumping and high vacuum.such as:vacuum smelting,power capacitors,transformers,vacuum impregnation treatment,vacuum coating equipment of pre-pumping and ... 500 3 5.2ZX1000 1000 3 9.5 Model ZX vacuum oil filter machine set