Patent ID: 6454524
Filing Date: 2002-09-24
Classification: F04D

Abstract:
A vacuum pump, comprising: an inlet port into which a first gas is pumped from a chamber to be evacuated; a gas feed section for pumping the first gas so that the gas enters the inlet port from the chamber to be evacuated and passes therethrough; an outlet port for discharging the gas pumped by the gas feed section; gas mixing means for mixing a second gas with the first gas within the vacuum pump so as to control the pressure within the chamber to be evacuated; and control means for controlling the gas mixing means when the vacuum pump is attached to the chamber to be evacuated to control the amount of the second gas to be mixed with the first gas by the gas mixing means so as to control the pressure in the chamber to have a desired value; wherein the gas feed section includes a turbomolecular pump section for pumping the first and second gasses, the turbomolecular pump section comprising plural stator blades fixed in a multi-stage manner in a gas feeding direction and respective rotor blades rotating between respective stator blades; and wherein the gas mixing means mixes the second gas with the first gas in the turbomolecular pump section.