KR20170049236A - Dry vacuum pump apparatus - Google Patents

Abstract

The present invention relates to a dry vacuum pump apparatus including a multi-stage positive displacement dry vacuum pump, such as a multi-stage root-type dry vacuum pump. When the dry vacuum pump is operated, in particular, at atmospheric pressure, the width of the rotor, which is proportional to the exhaust speed, becomes narrower as moving to the downstream side, so that exhaust gas accumulates in the rotor at the rearmost end to increase the pressure, and thus the present invention is designed to overcome the disadvantage of increasing the resultant entire power consumption.

Description

[0001] DRY VACUUM PUMP APPARATUS [0002]

The present invention relates to a dry vacuum pump apparatus including a multi-stage positive displacement vacuum pump, such as a multi-stage root type dry vacuum pump, and more particularly to a dry vacuum pump apparatus using a dry vacuum pump The width of the rotor that is proportional to the exhaust speed becomes narrower toward the rear end of the engine, so that the exhaust gas is accumulated in the rotor at the rear end, thereby increasing the pressure and thereby increasing the overall power consumption. To a dry vacuum pump apparatus.

In recent years, in a wide range of applications including semiconductor manufacturing facilities, dry vacuum pumping devices capable of operating under atmospheric pressure have been used to facilitate a clean vacuum environment. In particular, semiconductor devices are manufactured according to over 300 manufacturing steps, and there are numerous vacuum pumps used in the manufacturing process.

The dry vacuum pump device may be implemented with a multi-stage positive displacement dry vacuum pump, such as a multi-stage Roots type dry vacuum pump. Generally, a multi-stage Roots type dry vacuum pump is connected to a process chamber to suck and compress process byproducts, including gaseous materials generated in the process chamber.

When the gas is exhausted from the large-capacity chamber by using a multi-stage Roots type dry vacuum pump, the exhaust gas flows at a high speed in the inside thereof, so that different exhaust velocities at the respective stages of the pump cause It is excessively compressed. That is, in order to prevent the dry vacuum pump from operating under an overload, the compression force is increased to such a degree that the rotational speed control mode is triggered so as to lower the rotational speed of the dry vacuum pump. When the rotational speed of the dry vacuum pump is lowered, the exhaust velocities of the dry vacuum pump are also lowered, increasing the time required to exhaust the gas from the process chamber and consequently increasing the time required for the multi-stage Roots type dry vacuum pump Leading to an increase in the lead time of the semiconductor or liquid crystal device manufacturing equipment.

When the multi-stage Roots type dry vacuum pump is operated at atmospheric pressure, the width of the rotor, which is proportional to the exhaust speed, becomes narrower toward the rear end, so that the exhaust gas accumulates and the pressure rises. In case of the 5th stage, the pressure is increased up to 5.33 times as compared with the first stage, so that there is a problem of mechanical instability. In addition, excessive pressure of the rotor at the rear end places a burden on the four-stage rotor, thereby increasing power consumption.

Korean Published Patent Application No. 10-2011-0116992 (published on October 26, 2011) Korean Registered Patent No. 10-0855187 (Registered on August 25, 2008)

The present invention provides a dry vacuum pump device capable of reducing the total power consumption while relieving excessive pressure on dry vacuum pumps installed at the rear end.

A dry vacuum pump apparatus including a multi-stage constant-displacement dry vacuum pump according to a first embodiment of the present invention includes a first check valve connected to a final outlet for discharging exhaust gas generated from a rearmost rotor, An exhaust gas generated from a rotor at a front end of the rotor at a shortest distance from the rotor at a rear end of the rotor at a front end of the rear end rotor, And a second check valve connected to the exhaust outlet to be discharged.

The dry vacuum pump apparatus including the multi-stage constant-displacement dry vacuum pump according to the present invention is characterized in that the multi-stage constant-displacement dry vacuum pump includes a five-stage dry vacuum pump, and the exhaust gas generated from the dry- And the exhaust outlet to be discharged is connected to the fourth stage of the five-stage dry vacuum pump.

In the dry vacuum pump apparatus including the multi-stage constant-displacement dry vacuum pump according to the present invention, the multi-stage constant-displacement dry vacuum pump may be implemented as a multi-stage roots-type dry vacuum pump.

A dry vacuum pump apparatus according to the present invention comprises a first check valve connected to a final outlet for exhausting exhaust gas generated from a rearmost rotor and a second check valve provided at a front end of the rearmost rotor And a second check valve connected to an exhaust outlet for discharging the exhaust gas generated from a rotor of the front end of the rotor, which is installed at the shortest distance from the rear end of the rotor, , The total power consumption can be reduced while eliminating excessive pressure on the rear end rotor.

Further, the dry vacuum pump apparatus of the present invention includes a five-stage dry vacuum pump, and an exhaust outlet for discharging the exhaust gas generated from the front stage dry vacuum pump to the outside is connected to the fourth stage of the five- The pressure is not increased by more than a predetermined value, so that the mechanical stress can be reduced and the power consumption can be reduced.

Fig. 1 is a schematic configuration diagram of a dry vacuum pump apparatus according to the present invention.
2A is a vertical sectional view of a multi-stage roots type dry vacuum pump of the dry vacuum pump apparatus of the present invention.
FIG. 2B is a cross-sectional view taken along line AA of FIG. 2A.
3 is an exemplary view showing pressure and power consumption characteristics of the dry vacuum pump apparatus according to the present invention.
Fig. 4 is an exemplary view showing pressure and power consumption characteristics of a conventional dry vacuum pump apparatus.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 2 is a vertical cross-sectional view of a multi-stage roots type dry vacuum pump of the dry vacuum pump apparatus of the present invention, and FIG. 2B is a cross-sectional view of the dry vacuum pump apparatus of FIG. Sectional view taken along line AA of FIG.

The dry vacuum pump apparatus of the present invention includes a multi-stage roots type dry vacuum pump (hereinafter simply referred to as "dry vacuum pump") 10. The dry vacuum pump 10 is a five stage dry vacuum pump and includes two rotary shafts 11a and 11b which are rotatably supported by bearings 20 and 21 on opposite ends of the rotary shafts 11a and 11b Shaped rotors 12a, 12b, 12c, 12d, and 12e, respectively, which are fixedly mounted on the rotor 5a. The rotors 12a, 12b, 12c, 12d and 12e will also be collectively referred to as "rotors 12 ".

There are small gaps formed between the rotors 12 themselves and between the rotors 12 and the inner circumferential surface of the rotor casing 14 in which the rotors 12 are rotatably housed so that the rotating shafts 11a, When rotating about its own axes, the rotors 12 are rotated about the axes of the rotating shafts 11a, 11b without contacting each other. The rotor casing 14 internally defines rotor chambers 13a, 13b, 13c, 13d, and 13e housing each of the rotors 12a, 12b, 12c, 12d, and 12e. The gas pumped by the dry vacuum pump 10 is transferred through the rotor chambers 13a, 13b, 13c, 13d, and 13e. The rotor chambers 13a, 13b, 13c, 13d and 13e are arranged in a row along the rotating shafts 11a and 11b in the rotor casing 14. [ The rotor casing 14 has an upper surface covered with a cover member (not shown). The rotor casing 14 is formed on its upper surface and has an inlet 17 communicating with the rotor chamber 13a in the first stage. The rotor casing 14 also has an outlet side surface, the outlet side of which is covered by a first side casing 26 secured thereto. A bearing casing 23 for housing the bearings 21 therein is fixed to the side of the first side casing 26 away from the rotor casing 14. The first side casing 26 communicates with the rotor chamber 13e at the final stage and has a final outlet 18 formed at its side toward the rotor casing 14. [ A check valve is connected to the final outlet (18) to discharge the gas to the atmosphere.

A motor (e.g., a brushless DC motor) 22 is disposed on one side of the bearings 20 away from the rotor casing 14. The motor 22 has a motor rotor 22a fixed to one end of the rotating shafts 11a and 11b and a motor stator 22b disposed around the motor rotor 22a. The motor 22 is supplied with variable-frequency power from a power source such as an inverter device or the like (not shown), and the rotational speed including the soft starting mode of the dry vacuum pump 10 is controlled. The motor 22 is housed in the motor casing 24. If the motor 22 is comprised of a brushless DC motor, the rotors 12 are simultaneously rotated in opposite directions by the brushless DC motor through the rotating shafts 11a, 11b.

In each of the rotor chambers 13a to 13e, gas confined between the inner circumferential surface of the rotor casing 14 and the rotors 12 mounted on the rotating shafts 11a, 11b is discharged from the inlet side of the rotor chamber To the outlet side. The rotor casing 14 has internal and external walls 15a, 15b, 15c, 15d and 15e around the respective rotor chambers 13a, 13b, 13c, 13d and 13e, And a double-walled casing. The outlet side of the rotor chamber 13a communicates with the inlet side of the rotor chamber 12b by the gas path 15a. Similarly, the outlet sides of the rotor chambers 13b, 13c, 13d and 13e are connected to the inlet sides of the rotor chambers 13c, 13d and 13e by respective gas passages 15b, 15c, 15d and 15e, And the final outlet (18). Therefore, gas compressed by the rotor 12a in the rotor chamber 13a is transmitted through the gas passage 15a from the outlet side of the rotor chamber 13a to the inlet side of the rotor chamber 13b. Therefore, the gas is continuously compressed in the rotor chambers 13a to 13e, and is transferred to the final outlet 18 through the gas passages 15a to 15e.

Generally, in a multi-stage roots type dry vacuum pump, the volume of the rotor chamber at the initial stage is determined by the exhaust speed of the vacuum pump to be designed. Therefore, if the vacuum pump is designed for high exhaust speed, it is necessary to increase the volume of the rotor chamber at the initial stage. On the other hand, the volume of the rotor chamber at the rearmost end is used to reduce the heat (compression heat) to be produced by the pressure difference between the front and rear pressures in the rotor chamber at the last stage, It needs to be reduced in order to reduce the power consumption of the rotating motor. However, if the volume of the rotor chamber at the last stage is reduced, the gas can not be discharged smoothly. Since there is a trade-off between volume ratio and exothermic heat, it is determined whether the volume ratio (compression ratio) should be increased or decreased depending on which volume ratio and exotherm should be emphasized in designing the vacuum pumps.

The bearing 21 is disposed near the final outlet 18 of the dry vacuum pump 10. The rotary shafts 11a and 11b are rotatably supported by the bearing 20 and the bearing 21 located near the inlet 17. The bearing 21 is housed in the bearing casing 23 and the side casing 26 is disposed between the bearing casing 23 and the rotor casing 14. An unillustrated O-ring seal (sealing unit) is interposed between the bearing casing 23 and the side casing 26 to seal a small gap between the bearing casing 23 and the side casing 26. (Sealing unit) not shown is also interposed between the bearing casing 26 and the rotor casing 14 to seal a small gap between the side casing 26 and the rotor casing 14. The bearing (20) is housed in the motor casing (24). Another side casing 30 is disposed between the motor casing 24 and the rotor casing 14. An unshown O-ring seal (sealing unit) is interposed between the side casing 30 and the rotor casing 14. (Sealing unit) not shown is also interposed between the side casing 30 and the motor casing 24. The O-

According to the dry vacuum pump having the above-described structure, when the motor 22 is activated to rotate the rotating shafts 11a and 11b, the rotors 12a, 12b, 12c, 12d and 12e are rotated in the rotor chambers 13a, 13b, 13c, 13d, 13e. The progressively compressed gas is continuously passed through the gas passages 15a to 15e to the final outlet 18 from which the compressed gas is introduced into the exhaust unit 50 connected to the final outlet 18 do. The exhaust unit 50 discharges the gas to the atmosphere. The exhaust unit 50 includes a first check valve 51 connected to a final outlet 18 for exhausting the exhaust gas generated from the rearmost rotor 13e to the outside and a rearmost rotor 13e Of the plurality of rotors provided at the front end of the rotor 13a and the front end rotor 13d disposed at the shortest distance from the rear end of the rotor 13d, And a second check valve (52) connected to the exhaust outlet (19).

The exhaust outlet 19 serves to discharge the compressed gas from the fourth gas passage 15d to a higher pressure than the atmospheric pressure to reduce the power consumption of the dry vacuum pump 10 to the atmosphere.

FIG. 3 is an exemplary view showing pressure and power consumption characteristics of the dry vacuum pump apparatus according to the present invention, and FIG. 4 is an exemplary view showing pressure and power consumption characteristics of a conventional dry vacuum pump apparatus.

As shown in FIG. 3, when the dry vacuum pump apparatus according to the present invention is implemented as a five-stage roots-type dry vacuum pump, a first check valve 51 and a second check valve When the check valve 52 is provided, the pressure of the fifth stage does not rise above a predetermined value, so that the mechanical stress can be reduced and the power consumption of the fifth stage can be also reduced. Further, the power consumption of the entire dry vacuum pump apparatus according to the present invention can also be reduced.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined by the following claims. It will be understood.

Claims (3)

A dry vacuum pump apparatus comprising a multistage over-dry vacuum pump,
A first check valve connected to a final outlet for discharging the exhaust gas generated from the rearmost rotor to the outside; And
And exhausting the exhaust gas generated from a rotor of a front end rotor disposed adjacent to the rearmost rotor at a shortest distance among a plurality of rotors provided at a front end of the rearmost rotor, A second check valve connected to the exhaust outlet;
Wherein the vacuum pump is a vacuum pump. The method according to claim 1,
Wherein the multi-stage constant-displacement dry vacuum pump comprises a five-stage dry vacuum pump, and the exhaust outlet is connected to a fourth stage of the five-stage dry vacuum pump. The method according to claim 1 or 2,
Wherein the multi-stage constant-displacement dry vacuum pump is a multi-stage roots-type dry vacuum pump.

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