KR20140017635A - Vacuum pump - Google Patents

Abstract

In the vacuum pump 10 of the present invention, a pump casing 54 including a plurality of pump chambers 50a to 50f, an inlet port 52a, and an exhaust port 52b which are in fluid communication with each other and arranged in the longitudinal direction, and both ends rotate. A rotation shaft 58 that is possibly supported and extends in the longitudinal direction of the pump casing 54 and rotors 60a to 60f housed in the pump chambers 50a to 50f and connected to the rotation shaft 58. The pump casing 54 includes a first heat transfer member 72 and a first heat transfer member of the exhaust port 52b and a first heat transfer member 72 extending in parallel to the rotation axis 58 over the entire length of the pump casing 54 in the longitudinal direction. And a second heat transfer member 74 positioned proximate to the end of 72 and extending in the width direction of the pump casing 54.

Description

Vacuum pump {VACUUM PUMP}

The present invention is a vacuum pump used in a process such as a CVD process or an etching process, which is one of the manufacturing methods for the production of semiconductors, liquid crystals, solar cells, LEDs, etc., in particular a sublimable gas or a corrosive gas flows into the vacuum pump. It relates to a vacuum pump used in the process.

When evacuating the process gas introduced into the vacuum chamber using a vacuum pump, the vicinity of the intake port of the vacuum pump connected to the vacuum chamber is in the same level of vacuum as the vacuum in the vacuum chamber, and the vicinity of the exhaust port of the vacuum pump It is open to the atmosphere and is almost at atmospheric pressure. When the vacuum pump is operated to evacuate the process gas from the vacuum chamber, the heat of compression is generated in the vacuum pump because the process gas to be discharged is compressed by the vacuum pump.

In particular, in the case of evacuating the process gas in the vacuum chamber using the multistage vacuum pump, the process gas is transferred through the continuous pump chamber such as the first pump chamber, the second pump chamber, and the third pump chamber of the vacuum pump, thereby The pressure increases step by step and heat of compression is generated as the process gas is continuously compressed in the pump chamber. Therefore, in the vacuum pump, the process gas is transferred through the pump chamber while being pressurized step by step, and the temperature of the process gas also rises step by step through the pump chamber. In each pump chamber, the process gas has a higher pressure and temperature at the exhaust port than the intake port. Therefore, when evacuating the process gas from the vacuum chamber by using the multistage vacuum pump, it is likely to be low in the low pressure region close to the inlet of the multistage vacuum pump, and locally high temperature in the high pressure region near atmospheric pressure near the exhaust port of the multistage vacuum pump. It is easy to be.

For example, when a process gas containing a sublimable substance is introduced into a vacuum pump used for exhausting in the vacuum chamber, if the temperature in the vacuum pump is lower than the sublimation curve of the sublimable substance, the process gas introduced into the vacuum pump is contained. The sublimable substance is converted from gas to solid and precipitated in the vacuum pump, which makes the vacuum pump easy to stop.

On the other hand, when the temperature is high in the local region inside the vacuum pump, corrosion may occur due to the cleaning gas or the etching gas flowing into the vacuum pump.

In order to minimize the vaporization of the lubricant by effectively maintaining the temperature of the lubricating oil in the lubricating oil chamber while minimizing the temperature of the lubricating oil in the lubricating oil chamber, while maintaining the temperature of the pump chamber to be suitable for the exhaust of gas such as condensable gas or the sublimable gas, Between a relatively low temperature lubricating oil chamber, a dry pump having a hollow intermediate heat insulating chamber and a cooling passage through which a refrigerant is passed is proposed (see Japanese Patent Laid-Open No. 2005-105829).

In addition, the present applicant reduces the temperature difference between the inlet side and the outlet side, and precisely manages the clearance between the rotor and the rotor and between the rotor and the casing on which the rotor is supported without sacrificing corrosion resistance and mechanical strength of the rotor, thereby providing high exhaust. In order to obtain the performance, a core body (rotor shaft) having an axial hole formed in the axial direction therein, and a core portion formed of a material having a higher thermal conductivity than the material of the axial body inside the shaft hole, for example, a material such as aluminum A rotor for a rotary gas machine was proposed, including Japanese Patent Application Laid-Open No. 11-230060.

Patent Document 1: Japanese Patent Application Laid-Open No. 2005-105829 Patent Document 2: Japanese Patent Application Laid-Open No. 11-230060

However, the conventional vacuum pump maintains the inside of the vacuum pump at a high temperature throughout the vacuum pump, and prevents the precipitation of the product in the vacuum pump due to the sublimable material contained in the process gas flowing into the vacuum pump. However, it is not designed to prevent local areas in the vacuum pump from becoming hot above the corrosion temperature.

The present invention has been made in view of the above circumstances. An object of the present invention is to maintain a constant high temperature throughout the vacuum pump, i.e., the temperature in the vacuum pump uniformly throughout the vacuum pump, while preventing the local area in the vacuum pump from becoming a high temperature above the corrosion temperature. It is to provide a vacuum pump which can easily prevent the generation and precipitation of a product in a vacuum pump without requiring a heater or the like.

In order to achieve the above object, the vacuum pump of the present invention, a plurality of pump chambers in fluid communication with each other and arranged in the longitudinal direction, the intake port in fluid communication with one of the pump chambers located on the suction side, of the pump chamber located on the discharge side A pump casing having an exhaust port in fluid communication with one, a rotary shaft rotatably supported at both ends by a bearing and extending in the longitudinal direction of the pump casing, and accommodated in the pump chamber and rotating integrally with the rotary shaft. It includes a plurality of rotors connected. The pump casing is positioned in proximity to an end of the first heat transfer member extending in parallel to the rotation axis over the entire length of the pump casing in the longitudinal direction, and the width of the pump casing And a second heat transfer member extending in the direction.

The closer to the exhaust port, the higher the internal temperature of the pump chamber of the multistage vacuum pump. The first stage pump chamber has the lowest internal temperature, and the pump chamber close to the exhaust port has a high internal temperature. In each pump room, the area located on the outlet side is hotter than the area located on the upper inlet side. The first heat transfer member extending in parallel with the rotation axis over approximately the entire length of the pump casing, and the second heat transfer member disposed at a position close to the end of the first heat transfer member close to the exhaust port, provide heat of the pump casing that partitions the pump chamber. By uniformly dispersing in the longitudinal direction and the width direction of the pump casing and efficiently transferring heat from the high temperature region to the low temperature region, the inside of the vacuum pump is vacuumed while preventing the local region in the vacuum pump from becoming a high temperature above the corrosion temperature. The temperature is maintained at a constant high temperature throughout the pump, ie the temperature in the vacuum pump is uniformed throughout the vacuum pump. The first heat transfer member and the second heat transfer member are made of a good heat transfer material such as aluminum, aluminum alloy, copper, and the like.

Further, the other vacuum pump of the present invention is in fluid communication with one of a plurality of pump chambers in fluid communication with each other and arranged in the longitudinal direction, an intake port in fluid communication with one of the pump chambers located on the suction side, and one of the pump chambers located on the discharge side. A pump casing having an exhaust port, a rotary shaft rotatably supported at both ends by a bearing, and extending in the longitudinal direction of the pump casing, and a plurality of rotors accommodated in the pump chamber and connected to the rotary shaft to integrally rotate with the rotary shaft. Include. The pump casing includes an intermediate chamber disposed adjacent to the outside of one of the pump chambers in fluid communication with the exhaust port and in fluid communication with one of the pump chambers, and a process disposed inside the intermediate chamber and introduced into the intermediate chamber. And a divider forming a flow path for guiding the gas around the rotation axis.

As described above, the closer to the exhaust port, the higher the internal temperature of the pump chamber of the multistage vacuum pump. In each pump room, the area located on the outlet side is hotter than the area located on the upper inlet side. A part of the hot process gas discharged from the pump chamber of the last stage is introduced into the intermediate chamber, circulated along the flow path in the intermediate chamber, and the inlet side of the pump chamber of the final stage is heated. Is discharged out of the exhaust port. Therefore, a heater or the like is not required, and the inside of the pump chamber at the final stage is heated to a high temperature to prevent precipitation of the product in the vacuum pump.

Another vacuum pump of the present invention includes a plurality of pump chambers in fluid communication with each other and disposed in the longitudinal direction, an inlet port in fluid communication with one of the pump chambers located at the suction side, and an exhaust port in fluid communication with one of the pump chambers located at the discharge side. A pump casing comprising: a rotation shaft rotatably supported at both ends by a bearing and extending in the longitudinal direction of the pump casing; and a plurality of rotors accommodated in the pump chamber and connected to the rotation shaft to integrally rotate with the rotation shaft. do. The pump casing includes an end wall disposed at an end thereof and separated from a side panel disposed adjacent to the end of the pump casing.

Since the pump casing includes an end wall that divides the side panel disposed at its end and disposed adjacent to the end of the pump casing, all the rotors disposed in the pump chamber are wrapped by the pump casing. Thus, for example, the side panel cooled by the lubricating oil supplied to cool the bearing cools the process gas in the pump chamber and the pump casing, thereby preventing product from depositing in the vacuum pump.

As a preferred embodiment of the present invention, the pump casing includes an outer cylinder having a double wall structure having a gas flow path therein.

Since the outer cylinder has a double wall structure having a gas flow path therein, the inside of the pump chamber is reliably blocked from the outside by the high temperature process gas flowing through the gas flow path, so that the inside of the vacuum pump is kept at a low temperature so that the process gas The sublimable gas contained therein can be converted into a solid to prevent precipitation in the vacuum pump, that is, on the inner circumferential surface of the pump casing.

As a preferable aspect of this invention, the said pump casing contains the heat insulating jacket surrounding the outer peripheral surface.

The heat insulating jacket surrounding the outer circumferential surface of the pump casing warms the inside of the pump chamber to prevent the inside of the vacuum pump from becoming low temperature, and the sublimable gas contained in the process gas is changed into a solid, so that the vacuum casing, that is, the pump casing Can be prevented from being deposited on the inner circumferential surface.

According to the present invention, the production and precipitation of the product in the vacuum pump is maintained by maintaining the inside of the vacuum pump at a constant high temperature throughout the vacuum pump, that is, by equalizing the temperature in the vacuum pump throughout the vacuum pump without requiring a heater or the like. It is possible to prevent the corrosion of the vacuum pump and to provide a vacuum pump with high process reliability.

1 is a longitudinal front view showing a vacuum pump according to an embodiment of the present invention.
FIG. 2 is a longitudinal side view of the first stage pump chamber of the main pump provided in the vacuum pump shown in FIG. 1.
FIG. 3 is a perspective view showing a pump casing of the main pump provided in the vacuum pump shown in FIG. 1.
4 is a cross-sectional view taken along line XX of FIG. 2.
FIG. 5 is a sectional perspective view of the first stage pump chamber of the main pump provided in the vacuum pump shown in FIG. 1.
FIG. 6 is a diagram showing, on the electric motor side, side walls located close to the exhaust port of the pump casing of the main pump provided in the vacuum chamber shown in FIG. 1.

EMBODIMENT OF THE INVENTION Below, preferred embodiment of this invention is described with reference to drawings. 1 is a vertical front view showing a vacuum pump 10 according to an embodiment of the present invention. As shown in FIG. 1, the vacuum pump 10 includes a booster pump 12 disposed on the vacuum side and a main pump 14 disposed on the atmospheric side, which are connected by a connecting pipe 16. do. In the present embodiment, the main pump 14 is composed of a six-stage Roots vacuum pump, and the booster pump 12 is composed of a single Roots vacuum pump.

The booster pump 12 extends in the pump casing 22 and the pump casing 22 having the substantially cylindrical outer cylinder 20 in which the pump chamber 18 is partitioned inside, and is driven by the electric motor 24. It includes a pair of rotating shafts 26 rotatable in synchronization with each other in a reverse direction about the axis. A pair of rotors 28, such as a two-leafed rotor, are rotatably housed in the pump chamber 18 with a predetermined gap therebetween. The rotors 28 are fixedly mounted to the rotary shafts 26, respectively. The outer cylinder 20 of the pump casing 22 is formed in the wall, and is formed in the wall and the inlet port 20a connected to the discharge pipe (not shown) extending from the vacuum chamber or the like exhausted by the vacuum pump 10. An exhaust port 20b connected to the connecting pipe 16 is provided. When the rotor 28 is rotated synchronously in the opposite direction about the axis by the electric motor 24, the process gas in the vacuum chamber or the like flows into the pump chamber 18 through the inlet port 20a, the inside of the pump chamber 18 After being compressed by the rotor 28, it is discharged to the connecting pipe 16 through the exhaust port 20b. In FIG. 1, only one mechanism for driving the rotary shaft 26 based on the driving force from the rotary shaft 26, the rotor 28, and the electric motor 24 is shown. The rotating shaft, the rotor, and the other side of the mechanism are located on the opposite side of FIG. 1.

In the present embodiment, except for the inlet port 20a and the exhaust port 20b, the outer circumferential surface of the outer cylinder 20 of the pump casing 22 is surrounded by a substantially hollow cylindrical thermal insulation jacket 30. The thermal insulation jacket 30 keeps the inside of the pump chamber 18 at a constant temperature by thermally blocking the inside of the pump chamber 18 from the outside.

At the shaft end of the pump casing 22, two side panels 32a and 32b are disposed, respectively. The rotary shaft 26 is rotatably supported at its outer end by the bearings 36a and 36b housed in the bearing housings 34a and 34b respectively mounted to the side panels 32a and 32b. On each outer side surface of the side panels 32a and 32b, two lubricant housings 40a and 40b for holding the lubricant therein are disposed. The motor housing of the electric motor 24 is connected to one lubricating oil housing 40b.

The side panels 32a and 32b supply a purge gas such as N ₂ gas to a part of the rotating shaft 26 in the side panels 32a and 32b so that the process gas is transferred to the bearings 36a and 36b outside the pump chamber 18. Each purge gas flow path 42a, 42b is provided for preventing the outflow.

The booster pump 12 generally maintains a high vacuum level (low pressure level) inside and has low heat generation because it does not generate much compressed heat. Therefore, it is preferable to provide heating means such as a heater mounted on the outside or inside of the booster pump 12 to actively heat the booster pump 12. Except for the inlet port 20a and the exhaust port 20b, the thermal insulation jacket 30 surrounding the outer circumferential surface of the outer cylinder 20 of the pump casing 22 prevents the temperature in the pump chamber 18 from being lowered by the ambient air. It is effective to

The main pump 14 of this embodiment consists of a six-stage Roots type vacuum pump, and is provided with six pump chambers 50a to 50f, that is, a first stage pump chamber 50a to a sixth stage pump chamber 50f formed therein. A pump casing 54 having a cylindrical outer cylinder 52 and a pair of rotary shafts extending in the pump casing 54 and rotatable in synchronization with each other in a reverse direction with respect to the axis thereof in accordance with the driving of the electric motor 56 ( 58). As shown in FIG. 2, a pair of rotors 60a such as a three-lobe rotor are rotatably housed in the first stage pump chamber 50a disposed on the suction side of the main pump 14. Similarly, a pair of rotors 60b, such as a three-lobe rotor, is rotatably housed inside the second stage pump chamber 50b, and a pair of rotors 60c, such as a three-lobed rotor, is mounted on the third stage pump chamber 50c. It is housed rotatably inside. A pair of rotors 60d, such as a three-lobe rotor, is rotatably housed inside the fourth stage pump chamber 50d, and a pair of rotors 60e, such as a three-lobed rotor, is housed inside the fifth stage pump chamber 50e. It is rotatably accommodated, and a pair of rotors 60f, such as a 3-lobed rotor, are rotatably accommodated in the 6th stage pump chamber 50f arrange | positioned at the discharge side of the main pump 14. As shown in FIG. One linearly arranged rotors 60a to 60f are fixedly mounted to one of the rotary shafts 58, while the other linearly arranged rotors 60a to 60f are fixedly mounted to the other of the rotary shafts 58. .

The pump casing 54 includes end walls 62a and 62b for closing both ends of the outer cylinder 52, and five, i.e., first, partitioning walls 64a to fifth to divide the inside of the outer cylinder 52. It has a wall 64e. The first stage pump chamber 50a is formed between the end wall 62a and the first partition wall 64a in the outer cylinder 52. The second stage pump chamber 50b is formed between the first end wall 64a and the second dividing wall 64b in the outer cylinder 52. The third stage pump chamber 50c is formed between the second end wall 64b and the third partition wall 64c in the outer cylinder 52. The fourth stage pump chamber 50d is formed between the third end wall 64c and the fourth dividing wall 64d in the outer cylinder 52. A fifth stage pump chamber 50e is formed between the fourth end wall 64d and the fifth partition wall 64e in the outer cylinder 52. The sixth stage pump chamber 50f is formed between the fifth dividing wall 64e and the end wall 62b in the outer cylinder 52.

As shown in FIG. 2, when the rotor 60a rotates synchronously in the opposite direction with respect to the axis by the electric motor 56, the process gas is first-stage from the upper inlet side connected to the connecting pipe 16. As shown in FIG. It flows into the pump chamber 50a, is compressed by the rotor 60a in the first stage pump chamber 50a, and then discharged out of the lower outlet side from the first stage pump chamber 50a. Thereafter, the process gas is equally compressed in the second stage pump chamber 50b to the sixth stage pump chamber 50f.

The outer cylinder 52 of the pump casing 54 is formed in the side wall, is connected to the connecting pipe 16, and the inlet port 52a is in fluid communication with the upper inlet side of the first stage pump chamber 50a, and is formed in the side wall. An exhaust port 52b in fluid communication with the lower outlet side of the six-stage (final end) pump chamber 50f is provided. The outer cylinder 52 of the pump casing 54 has a double wall structure including an inner wall 66 and an outer wall 68 arranged outside at a predetermined distance from the inner wall 66, and the inner wall 66. The first gas passage 70a to the fifth gas passage 70e are formed between the outer wall 68 and the outer wall 68. Specifically, the first gas flow path 70a is formed around the first stage pump chamber 50a, and the second gas flow path 70b is formed around the second stage pump chamber 50b. The third gas passage 70c is formed around the third stage pump chamber 50c, the fourth gas passage 70d is formed around the fourth stage pump chamber 50d, and the fifth gas passage 70e is formed around the fifth stage. However, it is formed around the pump chamber 50e. In addition, the fifth gas flow path 70e is formed around the sixth stage pump chamber 50f.

The gas flow paths 70a to 70e have respective portions in fluid communication with the respective pump chamfers 50a to 50e through the respective lower outlet sides, and are in fluid communication to the respective pump chambers 50b to 50f through the respective upper inlet sides. Has its respective part. As shown in FIG. 2, the process gas flowing into the first stage pump chamber 50a from the suction port 52a through the upper inlet side is compressed in the first stage pump chamber 50a, and then the first stage pump chamber ( It flows into the 1st gas flow path 70a from 50a through the lower outlet side. The process gas flows upward in the first gas flow path 70a and reaches the upper inlet side of the second stage pump chamber 50b. The process gas flows into the second stage pump chamber 50b through the upper inlet side, and is compressed in the second stage pump chamber 50b, and then the second gas flow path (2) is passed through the lower outlet side from the second stage pump chamber 50b. 70b). The process gas flows upward in the second gas flow path 70b to reach the upper inlet side of the third stage pump chamber 50c. Thereafter, the process gas is compressed to pass through the third stage pump chamber 50c to the sixth stage pump chamber 50f. Thereafter, the process gas is discharged out of the main pump 14 via the exhaust port 52b from the lower outlet side of the sixth stage pump chamber 50f.

In the lower part of the pump casing 54 located below the lower outlet side of the pump chambers 50a to 50e, for example, a heat transfer member (first heat transfer member) 72 formed in a rod shape is embedded in the longitudinal direction. The heat transfer member 72 is located approximately centered in the width direction of the pump casing 54 and extends in parallel with the rotational axis 58 over approximately the entire length of the pump casing 54. As shown in FIG. 3, the heat transfer member 72 has an end exposed out of the pump casing 54 under the intake port 52a. Moreover, the position which is close to the edge part of the heat transfer member 72 of the exhaust port 52b side, in this embodiment, the 4th division wall 64d between the 4th stage pump chamber 50d and the 5th stage pump chamber 50e, the 1st In the fifth partition wall 64e between the five-stage pump chamber 50e and the sixth-stage pump chamber 50f, for example, a heat transfer member (second heat transfer member) 74 formed in a rod shape is embedded. The heat transfer member 74 is located below the lower outlet side of the pump chambers 50d to 50f and extends in the approximately full width direction of the pump casing 54. As shown in FIG. 3, the heat transfer member 74 has both ends exposed out of the pump casing 54.

The heat transfer members 72 and 74 are made of a material having good heat transfer properties such as aluminum, aluminum alloy, copper, and the like. The heat transfer members 72, 74 may be cut workpieces separate from the pump casing 54, or may be integrally molded with aluminum casting in the pump casing 54, which may be made of a corrosion resistant material.

The closer to the exhaust port 52b, the higher the internal temperature of the pump chamber of the multistage vacuum pump. Specifically, according to the present embodiment, the first stage pump chamber 50a has the lowest internal temperature, and the fifth stage pump chamber 50e and the sixth stage pump chamber 50f close to the exhaust port 52b have the highest internal temperature. . In each pump chamber, the region (lower region) located on the lower outlet side is hotter than the region (upper region) located on the upper inlet side. Specifically, the internal temperature is the highest in the region located on the lower outlet side of the fifth stage pump chamber 50e and the region located on the lower outlet side of the sixth stage pump chamber 50f.

In the present embodiment, the heat transfer member 74 disposed in the fourth partition wall 64d and the fifth partition wall 64e is located at the region of the highest temperature, that is, at the lower outlet side of the fifth stage pump chamber 50e. It serves to uniformly disperse the heat of the located area and the area located on the lower outlet side of the sixth stage pump chamber 50f in the width direction of the pump casing 54. The heat transfer member 72 extending in parallel with the rotational axis 58 over approximately the entire length of the pump casing 54 transfers heat in the high temperature region to the low temperature region, whereby the local region in the main pump 14 is above the corrosion temperature. While preventing the temperature from becoming high, the inside of the main pump 14 is maintained at a constant temperature of high temperature throughout the main pump 14, that is, the temperature in the main pump 14 is uniformized throughout the main pump 14. Therefore, by arranging the heat transfer members 72 and 74 inside the pump casing 54, the temperature at which the main pump 14 is corroded from the temperature at which the product precipitates in the pump casing 54 (for example, 110 ° C.) For example, within the required temperature range up to 200 ° C., the temperature may be maintained throughout the pump casing 54.

Since the outer cylinder 52 of the pump casing 54 has a double wall structure having gas flow paths 70a to 70e therein, the pump chamber 50a is formed by a high temperature process gas passing through the gas flow paths 70a to 70e. The inside of the ˜50f) is reliably blocked from the outside, and the inside of the main pump 14 is kept at a high temperature, whereby the sublimable gas contained in the process gas is changed into a solid, so that the inside of the main pump 14, that is, the pump casing Precipitation is prevented on the inner circumferential surface of (54). In particular, the high temperature process gas flowing from the lower outlet side of the pump chambers 50a to 50e to the upper inlet side of the pump chamber of the next stage through the gas flow paths 70a to 70e effectively heats the pump chambers 50a to 50f.

In the present embodiment, except for the inlet port 50a and the exhaust port 50b, the outer circumferential surface of the outer cylinder 52 of the pump casing 54 is surrounded by a thermal insulation jacket 80 formed in a substantially hollow cylindrical shape. The heat insulating jacket 80 keeps the inside of the pump chambers 50a to 50f at a constant temperature by thermally blocking the inside of the pump chambers 50a to 50f.

Two side panels 82a and 82b are disposed outside the end walls 62a and 62b of the pump casing 54, respectively. The rotating shaft 26 is rotatably supported at its outer end by the bearings 86a and 86b accommodated in the bearing housings 84a and 84b respectively mounted to the side panels 82a and 82b. On each outer side surface of the side panels 82a and 82b, two lubricant housings 90a and 90b for holding lubricant therein are disposed. The motor housing of the electric motor 56 is connected to one lubricant housing 90b. The side panels 82a and 82b supply a purge gas, such as N ₂ gas, to a part of the rotational shaft 58 in the side panels 82a and 82b so that the process gases are bearings 86a and 86b outside the pump chambers 50a to 50f. Each purge gas flow path (92a, 92b) for preventing the outflow.

In this embodiment, the end wall 62a of the pump casing 54 formed in the 1st stage pump chamber 50a is the rotor 60a accommodated in the 1st stage pump chamber 50a, and this rotor 60a. It is located between the side panels 82a which are disposed outside of. The end wall 62b of the pump casing 54 formed in the sixth stage pump chamber 50f includes a rotor 60f accommodated in the sixth stage pump chamber 50f and a side disposed outside the rotor 60f. Located between the panels 82b. Therefore, all the rotors 60a to 60f disposed in the pump chambers 50a to 50f are wrapped by the pump casing 54. Thus, for example, the side panels 82a and 82b cooled by the lubricating oil supplied to cool the bearings 86a and 86b cool the pump chambers 50a to 50f and the process gas in the pump casing 54, thereby providing a vacuum pump. The product precipitates in (10).

In this embodiment, between the end wall 62b of the pump casing 54 in which the 6th stage (final end) pump chamber 50f was formed, and the side panel 82b arrange | positioned outside this end wall 62b. The intermediate chamber 94 is formed. As shown in FIG. 4 and FIG. 6, the end wall 62b has an exhaust hole 96 formed substantially in the center in the width direction and positioned near the lower outlet side of the sixth stage (final stage) pump chamber 50f. Is formed. In addition, as shown in FIG. 6, two backflow holes 98 are formed in the end wall 62b and positioned at both the left and right sides of the exhaust hole 96. Two partition plates 100 are provided, which are respectively located between the exhaust holes 96 and the backflow holes 98 in the intermediate chamber 94 and extend from the respective rotating shafts 58 to the bottom surface of the intermediate chamber 94. do. The partition plate 100 prevents the process gas exhausted from the exhaust hole 96 directly flowing to the backflow hole 98. With this structure, as shown in FIG. 6, the partition plate 100 rises from the exhaust hole 96 in the intermediate chamber 94 to reach the rotary shaft 58, and then rotates the rotary shaft 58. And a gas flow path 102 descending toward the backflow hole 98.

In the present embodiment, the partition plate 100 is formed of a plate separate from the pump casing 54 and is fixed to the pump casing 54. However, the partition plate 100 may be formed integrally with the pump casing 54.

As described above, the pump chamber of the multistage vacuum pump near the final stage becomes the highest temperature, and the region near the outlet side of each pump chamber becomes higher than the region near the inlet side. Therefore, according to the present embodiment, a part of the high temperature process gas exhausted from the sixth stage (final stage) pump chamber 50f is introduced into the intermediate chamber 94 through the exhaust hole 96, and the gas flow path 102. Circulated in the intermediate chamber 94 to heat the inlet side of the sixth stage pump chamber 50f via the end wall 62b, and the high temperature process gas passes through the backflow hole 98 to exhaust port 52b. Exhaust out). Therefore, the inside of the 6th stage (final stage) pump chamber 50f becomes high temperature.

The vacuum pump 10 configured in this manner drives the booster pump 12 and the main pump 14 by driving the electric motor 24 of the booster pump 12 and the electric motor 56 of the main pump 14. Operating to, for example, evacuate the process gas introduced into the vacuum chamber from the vacuum chamber.

At this time, the interior of the vacuum pump 10 is maintained at a higher temperature throughout the vacuum pump 10, and thus, inside the vacuum pump 10 due to the sublimable material contained in the process gas introduced into the vacuum pump 10. While preventing the precipitation of the product, the local region in the vacuum pump 10 is prevented from becoming a high temperature above the corrosion temperature.

Although preferred embodiments of the present invention have been described, the present invention is not limited to the above-described embodiments, and various types such as claw vacuum pumps and screw-type vacuum pumps are provided within the scope of the technical concept included therein. Vacuum pumps may be applied.

Industrial availability

The present invention is applicable to a vacuum pump used in a process in which sublimable gas or corrosive gas may be introduced into the vacuum pump.

Claims (9)

A plurality of pump chambers in fluid communication with each other and disposed in the longitudinal direction; An intake port in fluid communication with one of the pump chambers located on the suction side; A pump casing having an exhaust port in fluid communication with one of the pump chambers located at the discharge side;
A rotating shaft rotatably supported at both ends by a bearing and extending in the longitudinal direction of the pump casing; and
A plurality of rotors housed in the pump chamber and connected to the rotary shaft to integrally rotate with the rotary shaft
Wherein the pump casing is positioned in proximity to an end of the first heat transfer member extending in parallel to the rotational axis over the entire length of the pump casing in a longitudinal direction, and on the exhaust port side; And a second heat transfer member extending in the width direction of the pump casing. The vacuum pump according to claim 1, wherein the pump casing includes an outer cylinder having a double wall structure having a gas flow path therein. The vacuum pump according to claim 1, wherein the pump casing includes a heat insulating jacket surrounding its outer circumferential surface. A plurality of pump chambers in fluid communication with each other and disposed in the longitudinal direction; An intake port in fluid communication with one of the pump chambers located on the suction side; A pump casing having an exhaust port in fluid communication with one of the pump chambers located at the discharge side;
A rotating shaft rotatably supported at both ends by a bearing and extending in the longitudinal direction of the pump casing; and
A plurality of rotors housed in the pump chamber and connected to the rotary shaft to integrally rotate with the rotary shaft
Wherein the pump casing includes: an intermediate chamber disposed adjacent to an outer side of one of the pump chambers in fluid communication with the exhaust port and in fluid communication with one of the pump chambers; And a divider forming a flow path for guiding the process gas introduced into the rotational axis. The vacuum pump according to claim 4, wherein the pump casing includes an outer cylinder having a double wall structure having a gas flow path therein. The vacuum pump according to claim 4, wherein the pump casing includes a heat insulating jacket surrounding its outer circumferential surface. A plurality of pump chambers in fluid communication with each other and disposed in the longitudinal direction; An intake port in fluid communication with one of the pump chambers located on the suction side; A pump casing having an exhaust port in fluid communication with one of the pump chambers located at the discharge side;
A rotating shaft rotatably supported at both ends by a bearing and extending in the longitudinal direction of the pump casing; and
A plurality of rotors housed in the pump chamber and connected to the rotary shaft to integrally rotate with the rotary shaft
Wherein the pump casing includes an end wall disposed at an end thereof and separated from a side panel disposed adjacent the end of the pump casing. The vacuum pump according to claim 7, wherein the pump casing includes an outer cylinder having a double wall structure having a gas flow path therein. 8. The vacuum pump according to claim 7, wherein the pump casing includes a heat insulating jacket surrounding its outer circumferential surface.

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