KR100624982B1 - Composite multistage dry vacuum pump having roots rotors and screw rotor - Google Patents

Abstract

A dry vacuum pump mainly for evacuating the process chambers of semiconductor and display manufacturing apparatus or for discharging gaseous substances and / or process by-products generated in the process chambers to the outside, thereby reducing the number of Roots-type rotors required An improved dry vacuum pump is disclosed that has a structure that eliminates the need for partition walls between the roots type rotor and the screw type rotors. Such a dry vacuum pump is provided with a space in which a material to be sucked can remain under one of the rooted rotors, and is connected to the lower one of the roots of the other roots and the roots of the roots of the screwed rotor. And a space in which the material to be sucked can remain, and includes a structure in which a space provided under the rooted rotor and an upper portion of the rooted rotor are communicated by a predetermined fluid passage.

Roots type rotor, screw type rotor, dry vacuum pump, dry vacuum pump

Description

Combined dry vacuum pump with multi-stage Roots type screw and screw type rotor {COMPOSITE MULTISTAGE DRY VACUUM PUMP HAVING ROOTS ROTORS AND SCREW ROTOR}

1 is a schematic cross-sectional view of a dry vacuum pump according to a preferred embodiment of the present invention;

2 is a view showing the principle of operating the Roots-type pump used in the dry vacuum pump according to a preferred embodiment of the present invention;

3 is a schematic cross sectional view of a conventional dry vacuum pump; And

4 is a view showing an embodiment of a roots-type pump used in a conventional dry vacuum pump.

* Description of the symbols for the main parts of the drawings *

1: dry vacuum pump 4: bulkhead (opening lower part)

6: bulkhead (open upper) 8: fluid passage

10 housing 12 suction port

13: 1st root type rotor 14: 2nd root type rotor

15: first powder pool 16: second powder pool

18: screw rotor 20: outlet

22a, 22b, 22c: bearing 24: shaft

26: drive motor 28: shear side wall

30: rear side wall

The present invention mainly relates to a dry vacuum pump for evacuating the process chambers of semiconductor and display manufacturing apparatus or for discharging gaseous substances and / or process by-products generated in the process chamber to the outside.

Dry vacuum pumps are typically used to evacuate process chambers of semiconductor and display manufacturing apparatus. Alternatively, a dry vacuum pump is used to discharge gaseous substances and / or process byproducts produced in the process chamber described above. Such a dry vacuum pump uses a Roots type rotor, a screw type rotor, or a combination rotor thereof.

Recently, such dry vacuum pumps have a roots rotor with at least one lobe and at least one screw rotor for the purpose of maintaining a complete vacuum in the process chamber and reducing the required power costs. ). The Roots-type rotor is connected to the process chamber described above and used to suck and compress the process by-products including gaseous substances generated in the process chamber, and the screw-type rotor is used for the gas and process by-products sucked by the Roots-type rotor. It is used to vent out of one process chamber. In any case, these rotors are operated closed to maintain vacuum in the process chamber.

Typically, partitions are provided between these rooted rotor stages and screwed rotor stages to allow process by-products to move smoothly from the rooted rotor stage to the screwed rotor stage without disturbing the rotation of the rotor. A representative example of such a configuration is disclosed in U.S. Patent No. 5,549,463 to Kashiyama Industry Co., Ltd. (see FIG. 3 below).

According to this patent document, the dry vacuum pump 100 includes a pair of Roots-type rotors 102 and 103 and a pair of screw-type rotors 105 and 106. The pair of Roots-type rotors 102 and 103 and the pair of screw-type rotors 105 and 106 are driven by one drive motor 104. That is, the power generated by such a drive motor 104 is connected by a pair of Roots-type rotors 102 and 103 and a pair of screw-type rotors 105 and 106 by three gears 124, 125 and 127. ) Is delivered to all. Between the Roots-type rotors 102 and 103 and the screw-type rotors 105 and 106, process by-products from the process chamber (not shown) as described above are transferred directly to the screw-type rotors 105 and 106. The partition 108 is provided so as not to. This patent is incorporated herein by reference in the present invention.

However, the partition 108 required in the dry vacuum pump 100 disclosed in the above-mentioned US Patent No. 5,549,463 is provided between the Roots-type rotors 102 and 103 and the screw-type rotors 105 and 106, namely And, since the housing 107 including them to be divided into several, it was a factor that increases the effort and the number of parts to manufacture such a dry vacuum pump 100.

In addition to the use of bulkheads, a variable pitch screw has been attempted to reduce the power consumption and increase the amount of process by-products compressed in dry vacuum pumps using a screw-type rotor. Effectiveness is estimated to be poor because of the need for larger rotors and pump housings.

In addition, a simple method of directly connecting them without a partition wall provided between the Roots-type rotor and the screw-type rotor was also attempted. The problem arises that the rotation of the rotor is disturbed by the process by-products.

On the other hand, conventional dry vacuum pumps comprise four to five Roots-type rotors in order to lower the power consumption resulting from their operation, that is, to further compress the gaseous process byproducts. The flow of process byproducts in these Roots-type rotors is shown in FIG. 4. A partition (not shown) is provided between the roots-type rotors. However, the conventional dry vacuum pump using these four to five Roots-type rotors must include a rotor housing, a paired rotor, a partition wall, and the like for each stage, thereby causing an increase in the number of parts and an increase in assembly costs. . In addition, such a conventional dry vacuum pump has a long and complicated internal path for inhaling and discharging gaseous process by-products and the like, causing problems such as an increase in gas leakage factor and accumulation of process by-products during actual operation.

 The present invention has been made to solve the above conventional problems, the object of the present invention is not only the partition wall between the Roots type screw and the screw type rotor, but also consumes less power while using fewer Roots type rotors. It is to provide a dry vacuum pump with an improved structure that can lower the amount and increase the amount of process by-products, such as compressed exhaust gas.

In order to achieve the above object, the present invention,

(a) a cylindrical housing on one side of which is provided a suction port for suctioning the substance to be sucked, and the other side of which is provided a discharge port for discharging the substance to be discharged;

(b) a Roots-type rotor accommodated in the housing, the one or more rotors being accommodated in communication with the suction port;

(c) a screw-type rotor accommodated in the housing and disposed in proximity to any one of the roots-type rotors;

(d) a shaft fixed through the center of the Roots-type rotor and the screw-type rotor and rotatably provided with the housing, the shaft being provided so that the inside and the outside of the housing are not in communication with each other; And

(e) a drive motor provided outside of the housing and connected to the shaft to drive the Roots-type rotor and the screw-type rotor in rotation;

In the lower portion of any one of the Roots-type rotor is provided a space for remaining the material to be sucked, the lower portion of the other of the Roots-type rotor, and the portion of the lower portion of the screw-type rotor connected to the Roots-type rotor A space in which the material to be sucked can remain is provided together, and a space provided under the Roots-type rotor and an upper portion of the Roots-type rotor provide a dry vacuum pump in communication with a predetermined fluid passage. As used herein, the term "substance to be absorbed" should be understood to include gaseous substances and / or process by-products generated in process chambers of semiconductor and display manufacturing devices.

As used herein, the terms "first roots rotor", "second roots rotor", "first powder pool" and "second powder pool", "first" and "second" refer to a substance to be inhaled. It should be understood as merely relying on the order of transit.

The expression "shear side" as used herein, unless otherwise specified, refers to the inlet side on the basis of the inlet port through which the inhaled material is sucked in the dry vacuum pump according to the present invention and the outlet through which the compressed inhaled material is discharged. It should be understood to represent.

The expression "rear side" as used herein, unless otherwise specified, refers to the outlet side on the basis of an outlet through which the suction target material is sucked and a compressed suction target material discharged from the dry vacuum pump according to the present invention. It should be understood to represent.

Hereinafter, a dry vacuum pump according to a preferred embodiment of the present invention with reference to the accompanying drawings will be described in more detail.

1 schematically shows a cross section of a dry vacuum pump according to a preferred embodiment of the present invention.

Referring to FIG. 1, a dry vacuum pump 1 according to a preferred embodiment of the present invention sequentially has a first Roots-type rotor 13 and a second Roots-type rotor 14 at a front end thereof, and at a rear end thereof thereof. The drive motor 26, preferably the water-cooled drive motor 26, has a screw rotor 18 between these first and second Roots-type rotors 13 and 14 and the drive motor 26. The screwed rotor 18 is coaxially coupled to the first and second rooted rotors 13, 14 with the aid of the shaft 24. Alternatively, the screwed rotor 18 may be coaxially coupled with the first and second rooted rotors 13, 14 without the aid of the shaft 24. For example, the second Roots-type rotor 14 and the screw-type rotor 18 may be manufactured integrally or separately and connected by connecting means such as welding. Such and modified modes of connection will be fully appreciated by those skilled in the art.

The first and second rooted rotors 13 and 14 and the screwed rotors 18 are provided in one cylindrical housing 10. The housing 10 is provided with a suction port 12 for sucking the substance to be sucked into the vacuum pump 1 above the Roots-type rotor 13 in the drawing. This inlet 12 is directly hermetically connected to the process chamber because the material to be sucked in the process chamber (not shown) of the semiconductor or display manufacturing apparatus must be sucked into the vacuum pump 1. In general, the cylindrical housing 10 including the inlet 12 is hermetically connected to the process chamber of the semiconductor or display manufacturing apparatus, and foreign matters of the alien space are also included in the space outside the housing 10 except the housing 10. It is hermetically connected to prevent inflow. Of course, the portion through which the shaft 24 penetrates is also hermetically connected to be blocked by the outside world. The inhalation target material sucked through the inlet 12 is provided with a lobe (alternatively, the second rooted rotor of FIG. 2) provided in the first rooted rotor 13 by the rotation of the first rooted rotor 13. 14), in particular between the lobes 14a and 14b) and transported opposite the inlet 12 (see FIG. 1 and FIG. 2 simultaneously).

The material to be sucked into the vacuum pump 1 with the aid of the first roots-type rotor 13 is again provided with a predetermined space (hereinafter referred to as " 15 " by rotation of the first roots-type rotor 13). 1 powder pool ") and after a short stay there is a second roots type via a fluid passage 8 defined as a partition 4 with a lower opening and a partition 6 with an upper opening as shown. It is conveyed to the top of the rotor 14. The suction object material transferred to the upper part of the second roots-type rotor 14 is again between the lobes 14a and 14b provided in the second roots-type rotors 14 by the rotation of the second roots-type rotors 14. The trapped and transported opposite the inlet 12 (see FIGS. 1 and 2 simultaneously) provides a predetermined space 16, hereinafter referred to as being provided at the bottom of the second rooted rotor and the bottom of the screwed rotor 18 simultaneously. 2 powder pool ") and then oriented to the screw-type rotor 18 by the pressure exerted by the second roots-type rotor 14. The second powder pool 16 has most of the space at the bottom of the second rooted rotor 14 and some space at the bottom of the screwed rotor 18 as shown. The powder root 16 provided below the second rooted rotor 14 and the screwed rotor 18 communicates with each other to form a space.

It should be noted that the dry vacuum pump 1 according to the preferred embodiment of the present invention has no partition wall between the second Roots-type rotor 14 and the screw-type rotor 18, unlike the conventional vacuum pump. A first powder pool 15 is provided below the first root-type rotor 13, and the first roots-type rotor 13 and the second roots-type rotor 14, together with the first powder pool 15, are described above. It is communicated by a fluid passage 8 defined by a partition 4 with an open bottom and a partition 4 with an open bottom. Conventional vacuum pumps require bulkheads and / or multiple Roots-type rotors in the presence of the bulkheads to reduce the power consumption in the vacuum pump and increase the amount of material to be sucked out, in particular gaseous, as described above. It became. Conventionally, such a partition has allowed the housing to be divided into several compartments as described above, but such multiple compartmentalization of the housing has been a factor in increasing the number of parts. This requirement has been solved by the present invention. In a preferred embodiment of the present invention, instead of using such a partition wall, a predetermined space 16, that is, a second powder pool (a lower portion of the second root type rotor 14 and a lower portion of the screw type rotor 18) By simultaneously placing the space 16, it was possible to eliminate the requirement of the bulkhead used in the prior art. In addition, conventionally, many, for example, four to five Roots-type rotors and thus partition walls between them have been required, thereby increasing the manufacturing cost of the dry vacuum pump. This requirement was also addressed with the direct help of the first powder pool 15 and the indirect help by the fluid passage 8.

Referring again to FIG. 1, the inhalation target material forced into the screw-type rotor 18 via the second powder pool 16 is rotated by the one-way rotation of the screw-type rotor 18 and the pressure transmitted in the previous stage. Compressed discharge is carried out through the discharge port 20 provided on the rear end side of the vacuum pump (1).

The shaft 24 provided through the cylindrical housing 10 is supported by the front side wall 28 and the rear end side wall 30 of the vacuum pump, respectively, with the aid of bearings 22a, 22b and 22c. In the figure, the shaft 24 right side shown on the right side is connected with the drive motor 26, in particular the water-cooled drive motor 26, and is rotated by its driving.

2 shows the driving principle of the first and second Roots-type rotors 13 and 14 used in the dry vacuum pump 1 according to the preferred embodiment of the present invention.

With reference to FIG. 2, the second roots type with the help of the above-described suction material or first roots type rotor 13 sucked into the interior of the dry vacuum pump 1 according to the present invention through the inlet 12. The material to be sucked transferred to the rotor 14 is trapped between its lobes 14a, 14b and 14c by the rotation of the first or second Roots-type rotor 13 or 14 as shown. It is transferred to the open space of or the space of the subsequent process. The principle of operation of such Roots type rotors themselves will be familiar to those skilled in the art.

As described above, the dry vacuum pump of the present invention does not use a partition wall between the Roots-type screw and the screw-type rotor, thereby preventing the increase in the number of parts due to compartmentalization of the housing, which is economically useful, and thus, the manufacturing process To be simplified. In addition, the dry vacuum pump of the present invention does not require a large number of Roots-type rotors and thus a large number of partitions, thereby making the manufacturing process cheap and simplifying the manufacturing process.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously changed and modified without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (5)

A cylindrical housing 10 provided with a suction port 12 for sucking a substance to be sucked on one side and a discharge hole 20 for discharging the discharge target material on the other side; A Roots-type rotor (13) (14), which is accommodated in the housing (10), wherein at least one is received so as to be in communication with the suction port (12); A screw-type rotor (18) accommodated in the housing (10) and disposed in proximity to any one of the roots-type rotors (13) and (14); The Roots-type rotors 13 and 14 are fixed to penetrate through the centers of the screw-type rotors 18 and are rotatably provided with the housing 10, and the inside and the outside of the housing 10 communicate with each other. A shaft 24 which is provided not to be closed; And It is provided on the outside of the housing 10, and is connected to the shaft 24 includes a drive motor 26 for rotationally driving the Roots-type rotor (13) 14 and the screw-type rotor (18) , A space 15 is provided below the one of the roots-type rotors 13 and 14 so that the substance to be sucked may remain, and the other one of the roots-type rotors 13 and 14 is provided. ) And a space 16 in which a material to be sucked can remain in a portion of the screw-type rotor 18 connected to the roots-type rotor 14, and the roots-type rotor 13. Dry space vacuum pump is provided in the lower portion of the (15) and the upper portion of the Roots-type rotor (14) is communicated by a predetermined fluid passage (8). 2. Dry vacuum pump according to claim 1, characterized in that the space (16) provided under the screwed rotor (14) is larger than the space (16) provided under the screwed rotor (18). 3. Dry according to claim 1 or 2, characterized in that the shaft (24) can rotate more smoothly with the aid of any one or more of the bearings 22a, 22b and 22c. Vacuum pump. The dry vacuum pump according to claim 1 or 2, wherein the drive motor (26) is a water-cooled drive motor. 4. The dry vacuum pump according to claim 3, wherein the drive motor (26) is a water-cooled drive motor.

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