Modular designed RV series roots vacuum pump can not be operated individually and should be used in connection with backing vacuum pump. The screw pump, oil seal pump and water ring pump are all suitable as backing pump for Roots pump. The Roots pump can be used to pump a mass of condensable gases when it connected with a screw pump or water ring pump. 
This oil-recirculating design is one of the simplest and most reliable vacuum pump available on the world market. These rugged pimps are used in a variety of industries such as packaging and food processing, rubber molding, thermoforming, printed circuit boad testing, hospitals, laboratories, roboticcs, vacuum lamination, printing, and degassing.

High Efficiency: can make sure the machine make full use of all the source, and cost down
Compact, simple design for easy installation and free maintenance 
Air-cooled, requiring no oil 
Quiet operation 
Coutinous duty 
High quality European made rotors