The individual Roots vacuum pumps were designed for use in aggregates in combination with a rotary vane pump as a variable pump. The functional principle of Roots vacuum pumps or vacuum boosters is very similar to that of rotary vane pumps. Through the entrance (A) air flows into the rotors (C D) formed conveyor cell in the housing. The cell is then pushed through the following piston head (f) separated from the inlet. The air in the cell (E) is now forwarded without reduction until it reaches the output (B) is reached, from where the air with higher absolute pressure is pushed from the pressure area into the incoming cell in order to then be expelled. Some models are equipped with an automatic by-pass valve (G), which limits the pressure difference between inlet and outlet.
*This description does not consider each manufacturer's approach to the technology, but represents a general description that attempts to cover the basic operating principle.