The Working Principle of Roots Vacuum Pump

Roots vacuum pump refers to a variable capacity vacuum pump equipped with two blade-shaped rotors that rotate synchronously in opposite directions. There is a small gap between the rotors and between the rotors and the inner wall of the pump casing without contact with each other. The gap is generally 0.1 to 0.8 mm; No oil lubrication is required. The rotor profiles include arc lines, involute lines, and cycloids. The volume utilization rate of the involute rotor pump is high and the machining accuracy is easy to ensure, so the rotor profile is mostly of the involute type.

The working principle of a Roots vacuum pump is similar to that of a Roots blower. Due to the continuous rotation of the rotor, the pumped gas is sucked into the space v0 between the rotor and the pump shell from the air inlet, and then discharged through the exhaust port. Since the v0 space is completely closed after inhalation, there is no compression or expansion of the gas in the pump chamber. But when the top of the rotor rotates around the edge of the exhaust port and the v0 space is connected to the exhaust side, due to the higher gas pressure on the exhaust side, some of the gas rushes back into the space v0, causing the gas pressure to suddenly increase. As the rotor continues to rotate, the gas is discharged from the pump.