This type pump department double class oil seal the machine change to permit the vacuum pump, it to have to face the atmosphere to directly line up the spirit’s characteristics, and be applicable to the electronics, make cold, give or get an electric shock the light source, chemical engineering, medical treatment, bottle the , packing, dehydrate, dry wait the profession.( but can’t used for the to divided by to contain the oxygen high, have the Bang of, to metals contain corrosion of, rise the chemical reaction to vacuum oil of and imply the air of the grain, dust, and also can’t be used as to transport the pump and compress the pump the usage).