Abstract: A vacuum pumping apparatus includes a pump housing 1 and a motor housing 8. The housings 1 and 8 are fastened together so as to be a sealed structure by O-rings 51-58 interposed therebetween. A shaft 17 of a driving device 70 and a driving shaft 15 carrying a rotor 2a are detachably connected via a coupling 91. During operation of the apparatus, a rotor chamber 41 in the pump housing 1 and a motor chamber 43 in the motor housing 8 are equalized in pressure, which requires no mechanical seal therebetween. The coupling 91 facilitates easy removal or detachment of a motor part B from a pump part A, which results in convenient maintenance of the pump part A.

Abstract: A multi-stage pump device includes a plurality of pump devices, each of the pump devices having a pump portion feeding working fluid under pressure, and a connecting portion provided between at least two of the pump devices, through which working fluid pumped by the respective pump devices passes. The connecting portion is expandable in a direction of the length thereof and is provided with a sealing structure to prevent a leakage of the working fluid. The connecting portion may be two telescopically arranged pipes or a bellows.

Abstract: A multistage vacuum pump unit having a plurality of separate single-stage pumps connected in series with each other by exhaust pipes, the exhaust pipes each connecting a suction port of one of the adjacent single-stage pumps with an exhaust port of another of the adjacent single-stage pump; motors for driving the separate single-stage pumps respectively; driving device for varying a revolution of one of the single-stage pumps that is at least in contact with an atmospheric side; driving current detection device for detecting a driving current of the motor for driving the single-stage pump that is in contact with the atmospheric side; pressure detection device for detecting a pressure at a vacuum-side inlet; and control device for controlling revolutions of the motors of the single-stage pumps based on the pressure detected by the pressure detection device.

Abstract: A multi-headed cryopump apparatus includes a plurality of cryopumps driven by a common compressor. There is a valve system between each cryopump and the compressor. A motor is provided for driving each cryopump, and a sensor is provided for detecting the amount of current supplied to each motor. By use of a control system, which accepts input from the sensors, the valve systems are controlled such that they operate in turn with a constant cycle.