JP2006299963A - Vacuum exhaust device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum exhaust device suppressing wasteful power consumption by reducing power voltage to be supplied to a motor after exhausting air in a vacuum tank in an atmospheric pressure to low vacuum range. <P>SOLUTION: The vacuum exhaust device comprises a vacuum pump 3 for exhausting air in the vacuum tank 1 and the motor 8 for driving the vacuum pump 3, a vacuum meter 7 for detecting a degree of vacuum in the vacuum tank 1, and a power voltage controller 10 for changing the voltage of a commercial power source to be supplied to the motor 8 depending on pressure in the vacuum tank 1 detected by the vacuum meter 7. After the air in the vacuum tank 1 is exhausted in an atmospheric pressure to vacuum range with the vacuum pump 3 driven by the motor 8, the power voltage to be supplied to the motor 8 is reduced several ten percent or so by the control of the power voltage controller 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vacuum evacuation apparatus for evacuating air in a vacuum chamber used for, for example, a vacuum film forming apparatus or a semiconductor device to maintain a vacuum state.

  In this type of evacuation apparatus, the inside of the vacuum chamber is evacuated using a vacuum pump. The inside of the vacuum chamber is evacuated from atmospheric pressure to a vacuum region by a vacuum pump. Then, a desired vacuum is maintained, and various processes are performed in the vacuum chamber under this state.

  The vacuum pump includes, for example, a three-phase induction motor, and is driven by supplying electric power from a commercial power source (200 V). Conventionally, a power supply voltage of a commercial power source is continuously supplied to the electric motor of the vacuum pump regardless of a change in pressure in the vacuum chamber, and the vacuum pump is operated.

  The electric motor of the vacuum pump is subjected to a maximum load when exhausting the inside of the vacuum chamber from the atmospheric pressure, and a large amount of electric power is consumed. When the inside of the vacuum chamber reaches the vacuum region, the load applied to the electric motor of the vacuum pump is reduced.

  That is, when evacuating from atmospheric pressure, the amount of exhaust is large and a large amount of energy is required for the exhaust. However, in the vacuum region, the amount of exhaust decreases, and exhaust with a small amount of energy is sufficient.

  Conventionally, however, the power supply voltage of the commercial power supply is continuously supplied to the vacuum pump motor regardless of the pressure change in the vacuum chamber, that is, the energy required for exhaustion changes. For this reason, there is a problem that the power consumption increases and the operation cost increases.

  The present invention has been made paying attention to such points, and its purpose is to lower the power supply voltage supplied to the electric motor after the vacuum chamber is exhausted from the atmospheric pressure to the vacuum region. Another object of the present invention is to provide an evacuation apparatus capable of suppressing unnecessary power consumption.

  The vacuum exhaust apparatus of the present invention includes a vacuum pump that exhausts the inside of a vacuum chamber, an electric motor that drives the vacuum pump, and a power supply voltage controller that can change the voltage of a commercial power source supplied to the electric motor. After the vacuum chamber is evacuated from the atmospheric pressure to the vacuum range by the vacuum pump driven by the electric motor, the power supply voltage supplied to the electric motor is controlled by the power supply voltage controller so that the rotation speed of the vacuum pump is less than a predetermined value. It is characterized by lowering to a range that does not become.

Most of the vacuum pump motors use three-phase induction motors, but the rotation speed N of the three-phase induction motors is
N = {(2f × 60) / P} × (1-S)
Where f: power supply frequency
P: Number of motor poles
S: Since it is a slip, it does not depend on the power supply voltage except for the influence of the load.

  Based on this principle, the vacuum evacuation device of the present invention is such that when the exhaust energy during vacuum decreases, the voltage supplied to the electric motor is reduced accordingly.

  According to the vacuum evacuation device of the present invention, after exhausting from the atmospheric pressure requiring a large amount of energy to the exhaust to the vacuum region, the power supply voltage of the commercial power source is supplied to the electric motor of the vacuum pump and driven. Since the power supply voltage supplied to the motor is lowered by the power supply voltage controller, useless power consumption can be suppressed and the operating cost can be reduced.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a configuration diagram of an evacuation apparatus. The evacuation apparatus includes a vacuum chamber 1, and a vacuum pump 3 is connected to the vacuum chamber 1 via an intake pipe 2. The vacuum pump 3 includes an intake port 4 and an exhaust port 5, an intake pipe 2 is connected to the intake port 4, and a main valve 6 is attached in the middle of the intake pipe 2.

  The vacuum chamber 1 is provided with a vacuum gauge 7 as vacuum degree detecting means for detecting the degree of vacuum inside, and the vacuum pump 3 is provided with an electric motor 8 for driving.

  Further, the evacuation apparatus is provided with a power supply voltage controller 10 that receives a signal output from the vacuum gauge 7 of the vacuum chamber 1 and controls the voltage of a commercial power supply supplied to the electric motor 8.

  During operation of this evacuation device, electric power at the commercial power supply frequency is supplied to the electric motor 8 of the vacuum pump 3 via the power supply voltage controller 10, and the electric motor 8 is activated by this electric power, and the vacuum pump 3 is driven.

  The pressure in the vacuum chamber 1 is sequentially detected by the vacuum gauge 7, and the signal is sent to the power supply voltage controller 10. When the pressure in the vacuum chamber 1 is shifted from the atmospheric pressure to the vacuum region, the power supply voltage of the commercial power supplied to the electric motor 8 by the power supply voltage controller 10 based on the signal sent from the vacuum gauge 7 is several. Controlled to reduce by 10%.

  For example, when the output voltage is lowered from 200 V to 150 V using an inverter capable of varying the output voltage, the number of rotations of the vacuum pump 3 is slightly lowered from 2912 rpm to 2760 rpm, but the vacuum in the vacuum layer 1 is maintained.

  At the start of operation, that is, when exhausting from the atmospheric pressure, there are a large amount of exhaust molecules, and the largest load is applied to the electric motor 8 of the vacuum pump 3. However, when moving to the vacuum region, the exhaust molecules decrease and the vacuum pump 3 is driven. The electric motor 8 is subjected to a load sufficient to rotate the pump. Therefore, even if the power supply voltage supplied to the electric motor 8 is reduced by several tens of percent, the rotation speed of the vacuum pump 3 is maintained almost constant and the vacuum state is maintained. It becomes possible.

  And by reducing the power supply voltage supplied to the electric motor 8, the power consumption of the electric motor 8 can be reduced, energy saving can be achieved, and the operating cost of the vacuum exhaust device can be reduced.

  FIG. 2 shows the relationship between the rotation speed, pressure, and power consumption of the vacuum pump 3 with respect to the supply voltage of the electric motor 8. As shown in FIG. It can be seen that the vacuum in the vacuum chamber 1 can be maintained by keeping the rotation speed of the pump 3 substantially constant, and the power consumption is reduced by lowering the power supply voltage.

The block diagram of the vacuum exhaust apparatus which concerns on one Embodiment of this invention. The graph which shows the relationship between the rotation speed of a vacuum pump with respect to the power supply voltage supplied to the electric motor of a vacuum pump, a pressure, and power consumption.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vacuum tank 2 ... Intake pipe 3 ... Vacuum pump 4 ... Intake port 5 ... Exhaust port 6 ... Main valve 7 ... Vacuum gauge 8 ... Electric motor 10 ... Power supply voltage controller

Claims (1)

A vacuum pump for exhausting the inside of the vacuum chamber, an electric motor for driving the vacuum pump, and a power supply voltage controller capable of changing a voltage of a commercial power supply supplied to the electric motor,
After the vacuum chamber is evacuated from the atmospheric pressure to the vacuum range by the vacuum pump driven by the electric motor, the power supply voltage supplied to the electric motor is controlled by the power supply voltage controller so that the rotation speed of the vacuum pump is less than a predetermined value. A vacuum evacuation device characterized by lowering it to a range that does not become necessary.

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