Patent ID: 8721295

Claim:
A vacuum pump apparatus with a self-diagnosis system for evacuating a reaction chamber, comprising: a Roots-type booster pump having a casing and a Roots-type rotor rotatably arranged in the casing for evacuating a reaction gas from the reaction chamber through rotation of the rotor driven by a first motor, wherein the Roots-type rotor has a plurality of rotor stages; a main pump having a casing and a rotor rotatably arranged in the casing for evacuating a discharge of the booster pump through rotation of the rotor driven by a second motor; a pressure sensor arranged to measure a pressure between the rotor stages in the casing of the Roots-type booster pump; and a control system which monitors and self-diagnoses the Roots-type booster pump and the main pump, wherein the control system is operable to: monitor a first current of the first motor for driving the Roots-type rotor, a second current of the second motor for driving the rotor of the main pump, and the pressure between the rotor stages in the casing of the Roots-type booster pump measured by the pressure sensor, self-diagnose the booster pump and the main pump such that the control system generates an alarm when a value of the first current of the first motor for driving the Roots-type rotor exceeds a predetermined current value if the measured pressure between the rotor stages in the casing of the Roots-type booster pump is below a predetermined lower pressure value, and cancel the self-diagnosis if the measured pressure between the rotor stages in the casing of the Roots-type booster pump is above a predetermined higher pressure value.