Hitachi, Ltd.

Akira Nishiuchi

Takashi Nagaoka

Masahiro Mase

Seiji Sakagami

Katsuaki Kikuchi

Shinjiro Ueda

Hirofumi Sakurai

Noboru Matsumura

Kimio Muramatsu

Ichiro Gyobu

Yoshihisa Awada

Keiji Ueyama

A dry turbo vacuum pump has a multistage circumferential impeller supported on a shaft, and a stator which cooperates with it to form a multistage peripheral flow pump. A centrifugal pump arranged at an inlet side of the peripheral flow pump is also mounted on the same shaft, so that gas sucked from the inlet is discharged to the atmosphere from the peripheral flow pump. The multistage peripheral flow pump and at least one stage of the centrifugal pump are integrated.

Vacuum pump

A turbo vacuum pump for compressing a low-pressure gas to discharge the compressed gas into atmosphere comprises pump stator having a gas flow passage comprising a plurality of annular flow passages on an inner surface thereof arranged stepwise diameters of which become smaller toward downstream and passages intercommunicating with adjacent annular flow passages and a gas discharge port communicated with one of the plurality of annular flow passages disposed at the most downstream. The pump stator includes a cylindrical spiral grooved pump impeller and a plurality of peripheral flow pump impellers facing the annular flow passages provided downstream of the cylindrical spiral grooved pump impeller and having stepwise diameters which become smaller toward downstream to form a peripheral flow pump stage. The suction casing has a spiral groove on a cylindrical inner surface thereof arranged with a predetermined clearance in relation to the spiral grooved pump impeller of the pump rotor so as to form a spiral grooved pump stage and a gas suction port communicated with the spiral grooved pump stage.

Turbo vacuum pump

A turbo vacuum pump has a housing provided with a suction port and a discharge port, an evacuation pump disposed in the housing for compressing a gas suctioned through the suction port and discharging the compressed gas through the discharge port, and a motor for driving the evacuation pump, the motor and the evacuation pump having a common rotor. The rotor is supported at its both axial ends by bearings. A spiral grooved dynamic seal is disposed in the vicinity of the suction port and at the opposite side of the suction port to the evacuation pump. The diameter of the spiral grooved dynamic seal, at the smallest, is greater than the outside diameter of the final stage impeller of the evacuation pumps.

A turbo vacuum pump has a housing provided with a suction port and a discharge port, an evacuation pump disposed in the housing for compressing a gas sucked through the suction port and discharging the compressed gas through the discharge port, and a motor for driving the evacuation pump, the motor and the evacuation pump having a common rotor. The rotor is supported at its both axial ends by bearings. A spiral grooved dynamic seal is disposed in the vicinity of the suction port and at the opposite side of the suction port to the evacuation pump. The diameter of the spiral grooved dynamic seal, at the smallest, is greater than the outside diameter of the final stage impeller of the evacuation pump.

A vacuum pump with a heating portion for preventing adhesion of reaction products on a discharge side thereof.

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Ibaraki, Japan

Akira Nishiuchi