| 摘要 |
PURPOSE:To aim at miniaturizing a multi-stage gas-discharge type rotary vacuum pump and at reducing the drive power thereof, by providing a communication passage connecting between the discharge port of a preceding stage operating chamber and the suction port of a next stage operating chamber so that multi-stage gas-discharge may be realized with only one set of a rotor and stator. CONSTITUTION:Both sides of a rotor 4 are made into contact with a cylinder chamber 3 along the minor diameter axis of the latter so that the cylinder chamber is equally divided into two operating chamber 6, 7 having an equal volume, on both sides of the major diameter axis with the discharge port 10 of the operating chamber 6 being communicated with the suction port 13 of the operating chamber 7 through a communication hole 14. With this arrangement, at first low pressure gas is sucked into the operating chamber 6 through the suction port 9 thereof in association with movement of a vane 5 accompanied with rotation of the rotor 3, and is discharged through a discharge valve which is opened. This discharged gas flows through the discharge port 1, a space 12 and the communication hole 14 and into the operating chamber 7 through the suction port 13, and is subjected to a gas-discharge process so that the discharged gas is released into the atmosphere. With this arrangement, multi-stage gas-discharge may be carried out only one set of a rotor 4 and a stator 2, thereby it is possible to miniaturize the multi-stage gas-discharge rotary vacuum pump and to reduce the drive power thereof.
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