1. Vacuum air pump 2. Used in power plant,vacuum metallurgy, welding, chemistry, pharmacy, coating and electronic industrie Waterproof&Dustproof Vacuum Insulation Oil Recycle MachineVacuum air pump fast in startup and pumping, and thus is especially suitable for vacuumization of transformers. Besides, it can also be used for vacuumization in vacuum metallurgy, welding, chemistry, pharmacy, ...