A. Description and principle：
Roots Vacuum Pumps, sometimes called
mechanical booster, are positive displacement
rotary vacuum pumps. Tow 8 cross-section
rotors are placed in the pump housing with
clearance and without touch. Two rotors are
rotated with high speed and kept a fixed relative
position between them by means of a pair of
synchronized gears. The working principle
drawing shown in right, From positionⅠ to Ⅳ
the pump finish the suction and exhaust course.
B. Main characteristics：
? High rotational speed and high volumetric efficient.
? simple structure，easy to operation and service.
? Rotors are locked，no displacement in axial direction .
? High precision gear and good dynamic balance，running low noise and low shake.
? No oil in pump cavity, satisfied different requirements.
? Lower power cost compare with other oil-sealed vacuum pumps.
? Wide range application, due to use different type backing pumps.
? Air-cooling and water-cooling meet different use.
C. Applications:
One of roots vacuum pump’s advantage is that it has a large pumping speed in very low pressure，but it
can’t be used lonely ，it must be equipped with a backing pump. When the system pressure is lower than the
pressure that permission the pump to startup, we can put the pump into use.
According many different pressure ranges and different process methods, we can use oil sealed vacuum
pump, liquid-ring vacuum pumps& reciprocating piston vacuum pumps for the backing pumps. Combining
with different type backing pump, the pump can get different pressure.
Roots vacuum pump can be widely used in any systems that need large pumping speed or middle
vacuum (10－1 ~10－2Pa), for example: vacuum coating/jointing furnace/heat treatment furnace/large scale
research/lamp and tube manufacture/laser engineering/vacuum packing/automotive industry/central vacuum
Systems/chemical Processing/deaeration /degasification/dehydration /freeze drying/distillation.