Rotary vacuum is an essential equipment to abtain vacuum by evacuating air in a sealing vessel.It is used for vacuum coating,evacuating of thermos flasks,Poly,lamp bulbs and electronic tubes,and vacuum use in medicine,chemistry and laboratories.It can be either operated individually or as a pre-stage pump incorporation with a booster pump,a diffusion pump or a molecular pump. During the pump's operation,appointed lubrication-oil and seal components are used.It is suitable for evacuation clean air which there is no chemical change while in contact with pump oil. Howerver, it is not suitable for evacuating gas which posseses particles of dust,a high content of oxygen,and a tendency to explode or corrode metals.