Vacuum pump and method of starting the same

Inactive Publication Date: 2006-09-07
EBARA CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0007] The present invention has been made in view of the above drawbacks. It is therefore an object of the present invention to provide a vacuum pump which can be normally started even if a product solidified or liquidized in a casing of the vacuum pump presents an obstacle to the rotation of the pump rotor.
[0015] According to the present invention, when the pump rotor can be rotated normally, a normal-starting operation is carried out, thus enabling the vacuum pump to be started quickly.

Problems solved by technology

Consequently, such product prevents the rotation of the pump rotors, and hence the pump rotors cannot be rotated by a starting torque of the motor, thus causing a failure of the restart of the vacuum pump.
Further, in addition to the failure of the restart of the vacuum pump, an excessive load is applied to the motor to cause the motor to overheat, and hence the vacuum pump cannot be operated safely.
If such a motor-drive technique is used in the vacuum pump, a torque of the motor for starting the vacuum pump is limited by capacities of parts used in the inverter.
Consequently, the motor can generate only a limited torque, and the starting operation of the vacuum pump tends to be more difficult.

Method used

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  • Vacuum pump and method of starting the same
  • Vacuum pump and method of starting the same
  • Vacuum pump and method of starting the same

Examples

Experimental program
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Effect test

first embodiment

[0029] Although a vacuum pump according to the present embodiments is used for evacuating a gas from a chamber used in a semiconductor fabrication apparatus, the present invention is not limited to such an application. FIG. 1 is a cross-sectional view showing a vacuum pump according to the present invention.

[0030] As shown in FIG. 1, the vacuum pump according to the first embodiment comprises a pair of pump rotors 1, 1 each having a screw groove, a casing 2 for housing the pump rotors 1, 1, and a motor 3 for rotating the pump rotors 1, 1. The casing 2 has an inlet port 7 for drawing a gas therein and an outlet port 8 for discharging the gas therefrom. The pump rotors 1, 1 are fixed respectively to two shafts 4, 4 which are rotatably supported by bearings 5, 5.

[0031] One of the shafts 4, 4 has a motor rotor 3a fixed thereto, and a motor stator 3b is disposed so as to enclose the motor rotor 3a. The motor rotor 3a and the motor stator 3b constitute the motor 3. In this embodiment, th...

second embodiment

[0041]FIG. 3 is a schematic view showing a control system including a pump-rotor controller according to the present invention.

[0042] As shown in FIG. 3, a control system of this embodiment comprises a three-phase power source 11, an earth leakage breaker (ELB) 12, and a frequency converter 21. The three-phase power source 11 is connected to the frequency converter 21 through the earth leakage breaker (ELB) 12, and the frequency converter 21 is connected to the motor 3. The frequency converter 21 comprises a rectifier 22, a power transistor 23 for generating a waveform to rotate the motor 3, and a frequency-conversion controller 24 for controlling the frequency converter 21. A pump-rotor controller 15 for controlling rotation of the pump rotors 1, 1 and stop of the pump rotors 1, 1 is connected to the frequency converter 21.

[0043] The pump-rotor controller 15 includes a timer 16, as with the first embodiment. Specifically, when a start-switch (not shown) is operated, a start-comman...

third embodiment

[0046]FIG. 4 is a schematic view showing a control system including a pump-rotor controller according to the present invention.

[0047] As shown in FIG. 4, a control system comprises a three-phase power source 11, an earth leakage breaker (ELB) 12, a first electromagnetic contactor 13A, a second electromagnetic contactor 13B, and a thermal protector 14. An induction motor is used as the motor 3. The first electromagnetic contactor 13A and the second electromagnetic contactor 13B are connected to a pump-rotor controller 15, respectively, and are activated by receiving an operation-command signal from the pump-rotor controller 15. The three-phase power source 11 is connected to the first electromagnetic contactor 13A and the second electromagnetic contactor 13B through the earth leakage breaker (ELB) 12, and the first electromagnetic contactor 13A and the second electromagnetic contactor 13B are connected to the motor 3 through the thermal protector 14. The first electromagnetic contact...

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Abstract

The present invention relates-to-a-vacuum pump and a method of starting a vacuum pump. The vacuum pump includes a pump rotor (1) rotatably disposed in a casing (2), and a pump-rotor controller (15) for controlling rotation of the pump rotor (1) in a forward direction or a reverse direction in accordance with a predetermined pattern at the time of starting the vacuum pump.

Description

TECHNICAL FIELD [0001] The present invention relates to a vacuum pump and a method of starting a vacuum pump, and more particularly to a vacuum pump for evacuating a gas from a chamber used in a semiconductor fabrication apparatus or the like, and a method of starting such a vacuum pump. BACKGROUND ART [0002] In a semiconductor fabrication apparatus, a vacuum pump is widely used for evacuating a gas used in a semiconductor fabrication process from a chamber and producing a vacuum environment in the chamber. As this type of vacuum pump, there has been known a positive-displacement vacuum pump having Roots-type or screw-type pump rotors. [0003] Generally, the positive-displacement vacuum pump comprises a pair of pump rotors disposed in a casing, and a motor for rotating the pump rotors. A small clearance is formed between the pair of the pump rotors themselves and also between the pump rotors and the inner surface of the casing so that the pump rotors are rotated in a noncontact manne...

Claims

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Application Information

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IPC IPC(8): F04B49/06F04C13/00F04C18/12F04C18/16F04C28/06F04C28/28F04D19/04F04D27/02
CPCF04C13/005F04C18/126F04C18/16F04C28/06F04C28/28F04D27/0292F04C2270/03F04C2270/17F04C2270/701F04C2270/80F04D19/04F04C2220/12F05D2260/607F04C28/00F04C13/00
InventorIIJIMA, NAOKIWATANBE, JIROCHINO, HIROYUKIYANAGISAWA, KIYOSHIKAWAMURA, TAKESHI
OwnerEBARA CORP