Rotary Dry Vacuum Pump

Abstract

Conventionally, when a canned motor is used in the drive part of a rotary dry vacuum pump, there is found a problem that reaction produced gas flows into the interior of the canned motor to thereby break down the canned motor and thus the rotary dry vacuum pump. To solve this problem, according to the invention, there is provided a rotary dry vacuum pump comprising a rotary rotor composed of one or plural rotors housed within a housing, bearings for supporting respectively the rotary shafts of these rotors, a suction port and an exhaust port formed in the housing respectively for sucking and exhausting fluid, and a rotary rotor composed of a motor for driving and rotating at least one of the rotors, wherein the motor includes a stator core fixed to the inside of the housing of the motor, a partition wall mounted on the rotor inner peripheral side is fixedly secured to the housing to thereby hermetically seal the interior of the partition wall, a rotary element is rotatably disposed on the shaft within the partition wall to thereby provide a rotatable structure, and there is opened up in the motor a gas charge hole for charging purge gas into the partition wall.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[FIG. 1] It is an axial section view of a screw vacuum pump according to the invention.

DESCRIPTION OF REFERENCE NUMERALS AND SIGNALS

• 200: Vacuum pump
• 202, 204: Screw rotor
• 210: Housing
• 210 b: Screw rotor storage chamber
• 231, 233, 234, 236: Bearing
• 251, 253: Timing gear
• 237, 238, 239, 240: Shaft seal
• 241: Canned motor
• 261: Stator core
• 263: Shaft portion
• 265: Rotary element
• 267: Flange
• 269: Charge hole
• 271: Flow passage

Claims

1. A rotary dry vacuum pump with a rotary rotor comprising: one or plural rotors housed within a housing;bearings for supporting respectively shafts of the rotors;a suction port and an exhaust port respectively formed in the housing for sucking and exhausting fluid; and,a motor for driving and rotating at least one of the rotors,wherein the motor includes a stator core,a partition wall mounted on an inner peripheral side of the stator core is fixedly secured to the housing to thereby hermetically seal an interior of the partition wall, a rotary element is rotatably disposed within the partition wall, the shaft of at least one of the rotors and shaft of the rotary element are fixedly secured to thereby be able to drive and rotate the rotor, and a gas charge hole is provided for charging purge gas into the partition wall.

2. A rotary dry vacuum pump as set forth in claim 1, wherein the shaft of the motor and the shaft of the rotor are formed integral with each other.

3. A rotary dry vacuum pump as set forth in claim 1, wherein the motor is disposed on a suction port side of the vacuum pump.

4. A rotary dry vacuum pump as set forth in claim 1, wherein flow rate control means is disposed on a pipe for sending the purge gas to the purge gas charge hole.

5. A rotary dry vacuum pump as set forth in claim 1, further including a pressure measuring device for measuring the pressure of the interior of the partition wall and/or a pressure measuring device for measuring the pressure of the interior of an exhaust chamber.

6. A rotary dry vacuum pump as set forth in claim 1, further including a measuring device for measuring the number of rotations of the rotary element of the motor and the rotor.

7. A rotary dry vacuum pump as set forth in claim 1, further including means for measuring the power consumption of the motor.

8. A rotary dry vacuum pump as set forth in claim 1, wherein a gas flow meter is disposed in the vicinity of the suction port or exhaust port or within a vacuum chamber.