JP2005105829A - Dry pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dry pump for restraining vaporization of lubricating oil to be advantageous to maintaining the temperature of lubricating oil of a lubricating oil chamber low, while maintaining the temperature of a pump room high so as to be suitable for exhaust of gas such as condensing gas and sublimating gas. <P>SOLUTION: This dry pump 1 has a housing body 1x having the pump room, rotor rotating members 34 and 34', and a lubricating oil housing 31 arranged in the housing body 1x, and having the lubricating oil chamber 33 for storing the lubricating oil 32. The housing body 1x has both a hollow thermally insulating intermediate chamber 26 formed between the pump room 11 of the relatively high temperature and the lubricating oil chamber 33 of the relatively low temperature, and a cooling passage 30 formed between the pump room 11 and the lubricating oil chamber 33, and passing a refrigerant. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a dry pump that forms a reduced pressure state. A dry pump is a pump that aims to be oil-free and eliminates lubricating oil in a pump chamber through which gas flows.

  The background art will be described using a multistage dry pump as an example. The multi-stage dry pump includes a pump housing having a plurality of pump chambers arranged side by side, a rotor rotating member rotatably provided in the pump chamber, and a lubricating oil chamber that is disposed on the end side of the pump housing and stores lubricating oil And a lubricating oil housing. The rotor rotating member includes a rotating shaft erected on the housing body and a plurality of rotors integrally disposed on the rotating shaft so as to be positioned in the pump chamber.

  According to such a multistage dry pump, while maintaining a slight gap between the rotors and between the rotor and the inner wall surface of the pump housing, the rotor rotating member is rotated in the pump chamber, and the pump housing air inlet The introduced gas is compressed in multiple stages and exhausted to the atmosphere from the exhaust port, thereby obtaining a reduced pressure atmosphere. In order not to affect the decompressed atmosphere, the pump chamber is targeted for an oil-free state in which the lubricating oil is eliminated.

According to such a multistage dry pump, since compression heat is generated in the compression process of the exhausted gas, it is preferable to provide a cooling device for removing the compression heat. Therefore, conventionally, as disclosed in Patent Documents 1 and 2, a cooling device is directly provided on the outer wall portion of the pump housing to cool the pump chamber.
Japanese Patent No. 2611168 Japanese Patent No. 3051515

  However, according to the multistage dry pump according to Patent Documents 1 and 2 described above, a cooling device is provided on the outer wall of the pump housing to directly cool the pump chamber, so that cooling of the pump chamber is promoted, It was difficult to keep the inside of the pump at a high temperature. For this reason, when a gas such as a condensable gas or a sublimable gas is exhausted by a multistage dry pump, the gas is solidified or liquefied by sublimation or condensation, and the substance is between the rotors or between the rotor and the pump housing. It may adhere between the inner wall surface of the chamber. In this case, smooth rotation of the rotor is impaired by these substances. In extreme cases, the pump could overload and stop.

  In addition, in order to realize a dry pump that suppresses liquefaction or solidification of the gas such as the condensable gas and the sublimable gas and has improved durability against the condensable gas and the sublimable gas, the inside of the pump is heated Therefore, it is preferable to keep the outer peripheral surface of the pump housing at a high temperature. However, in this case, since the cooler is directly provided in the pump housing, the cooling water may become high temperature (for example, 100 ° C. or higher). In this case, there is a problem that cooling water with a large amount of steam, in particular, boiling cooling water is difficult to flow, and a satisfactory cooling effect cannot be obtained.

  Further, according to the dry pump described above, the rotation speed of the rotor rotating member is often high speed rotation (for example, 3000 rpm or more). In order to maintain such a rotational speed, it is preferable to suppress overheating of the lubricating oil that lubricates the mechanical parts such as the bearings and the timing gear, and therefore it is preferable to cool the lubricating oil efficiently. According to the dry pump described above, since the lubricating oil housing having the lubricating oil chamber is directly attached to the pump housing, heat is transmitted from the pump chamber having a high pump housing temperature to the lubricating oil housing, and the lubricating oil There was also a problem of incurring a temperature rise. Thus, when the temperature of lubricating oil becomes high, deterioration of lubricating oil will progress, oil viscosity will fall, and it will become difficult to hold | maintain a lubricating oil film. Furthermore, the vaporization of the lubricating oil increases. In this case, although the pump chamber is sealed with the seal member, the vaporized lubricating oil is very fine particles, and thus may pass through the seal member and enter the pump chamber. In high vacuum processes such as semiconductor manufacturing processes and liquid crystal manufacturing processes where high vacuum properties are required, even if the amount of lubricant mist is extremely small, the process may be affected. It is not preferable to enter the chamber.

  The present invention has been made in view of the above-mentioned circumstances, and a common problem of each claim is to maintain the temperature of the pump chamber high so as to be suitable for exhausting gases such as condensable gas and sublimable gas. At the same time, the lubricating oil stored in the lubricating oil reservoir can be cooled well, which is advantageous for suppressing deterioration of the lubricating oil. An object of the present invention is to provide a dry pump in which the lubricating oil is prevented from entering the pump chamber.

A dry pump according to aspect 1 includes a housing body having a pump chamber and an intake port and an exhaust port communicating with the pump chamber, a rotating shaft installed in the housing body, and a pump chamber that is integrated with the rotating shaft. A rotor rotating member that is composed of a rotor disposed and that compresses the gas sucked from the intake port as it rotates and exhausts it from the exhaust port; and a lubricating oil reservoir that is disposed in the housing body and stores the lubricating oil. In dry pump
The housing body includes a heat insulating intermediate chamber formed between the pump chamber and the lubricating oil reservoir, and a cooling passage formed between the pump chamber and the lubricating oil reservoir for allowing the refrigerant to pass therethrough. It is characterized by having.

  According to the dry pump according to aspect 1, in the housing body, the hollow intermediate chamber is provided between the pump chamber and the lubricating oil reservoir, and the hollow chamber functions as a space for heat insulation. Heat transfer from the pump chamber to be maintained to the side of the lubricating oil reservoir that is to be maintained at a low temperature is suppressed, which is advantageous for maintaining the pump chamber at a high temperature while maintaining the lubricating oil reservoir at a low temperature. Therefore, even when exhausting gases such as condensable gas and sublimable gas, liquefaction or solidification of these in the pump chamber can be suppressed.

  Further, in the housing body, the cooling passage through which the refrigerant passes is formed between the pump chamber and the lubricating oil reservoir, which is advantageous for cooling the lubricating oil in the lubricating oil reservoir and maintaining it at a low temperature. Thus, deterioration of the lubricating oil can be suppressed, and the rotating property of the rotor rotating member, in particular, the high-speed rotating property can be maintained. Further, since the lubricating oil can be kept at a low temperature and the vaporization of the lubricating oil can be suppressed, the vaporized lubricating oil is prevented from entering the pump chamber, which is advantageous for making the pump chamber oil-free. Any refrigerant can be used as long as it can cool the cooling housing and has fluidity, and generally includes cooling water, cooling oil, and the like. In the present specification, high temperature and low temperature, high temperature and low temperature are relative temperatures.

  The dry pump according to aspect 2 is characterized in that the intermediate chamber and the cooling passage are formed in this order from the pump chamber toward the lubricating oil reservoir. As a result, an intermediate chamber that functions as a heat insulating space is formed on the pump chamber side that is desired to be maintained at a high temperature, so that heat transfer from the pump chamber to the lubricating oil reservoir side is suppressed, and the temperature of the lubricating oil reservoir portion is reduced. It is advantageous to keep the temperature of the pump chamber high while keeping the temperature low. Furthermore, since a cooling passage is formed on the side of the lubricating oil reservoir that is desired to be maintained at a low temperature, the lubricating oil stored in the lubricating oil reservoir can be efficiently cooled by the refrigerant in the cooling passage. It is advantageous for keeping the temperature of the stored lubricating oil low and suppressing deterioration of the lubricating oil. Further, since the vaporization of the lubricating oil can be suppressed, it is advantageous for making the pump chamber oil-free.

  According to the dry pump according to aspect 3, the housing main body has a pump housing having a pump chamber, a side housing attached to at least one end of both ends of the pump housing, and a side housing opposite to the pump housing. And an intermediate chamber is formed in the side housing, and a cooling passage is formed in the cooling housing.

  As a result, an intermediate chamber that functions as a heat insulation space is formed on the pump chamber side that is desired to be maintained at a high temperature, so that heat transfer from the pump chamber can be suppressed, and the temperature of the lubricating oil reservoir is kept low. However, it is advantageous to keep the temperature of the pump chamber high. Further, since the cooling passage is formed on the side of the lubricating oil reservoir, the lubricating oil stored in the lubricating oil reservoir can be cooled by the refrigerant in the cooling passage and is stored in the lubricating oil reservoir that is desired to be maintained at a low temperature. This is advantageous for keeping the temperature of the lubricating oil low. Further, since the vaporization of the lubricating oil can be suppressed, it is advantageous for making the pump chamber oil-free.

The dry pump according to aspect 4 has a housing body having a pump chamber and an intake port and an exhaust port communicating with the pump chamber, a rotating shaft installed in the housing body, and a pump chamber that is integrated with the rotating shaft. A rotor rotating member that is composed of a rotor disposed and that compresses the gas sucked from the intake port as it rotates and exhausts it from the exhaust port; and a lubricating oil reservoir that is disposed in the housing body and stores the lubricating oil. In dry pump
The housing body includes a pump housing having a pump chamber, a side housing attached to at least one end of both ends of the pump housing, and a cooling housing attached to the side of the side housing opposite to the pump housing. And the cooling housing has a cooling passage for allowing the refrigerant to pass between the pump chamber and the lubricating oil reservoir, and the side housing is based on a material having a lower heat transfer coefficient than the cooling housing, The cooling housing is characterized in that the base material is a material having a higher heat transfer coefficient than the side housing.

  In this case, the pump housing, the side housing, and the cooling housing are formed in this order from the pump chamber to be maintained at a high temperature toward the lubricating oil storage portion to be maintained at a low temperature, and the cooling housing close to the lubricating oil storage portion to be maintained at a low temperature. A cooling passage is formed in the front. For this reason, the lubricating oil stored in the lubricating oil storage section that is desired to be maintained at a low temperature can be efficiently cooled by the refrigerant in the cooling passage of the cooling housing. Therefore, the temperature of the lubricating oil stored in the lubricating oil storage section can be kept low, which is advantageous for suppressing deterioration of the lubricating oil. Further, since the vaporization of the lubricating oil can be suppressed, it is advantageous for making the pump chamber oil-free.

  According to the dry pump according to aspect 4, the side housing is based on a material having a lower heat transfer coefficient than the cooling housing, so heat transfer from the pump chamber to be maintained at a high temperature to the lubricating oil reservoir to be maintained at a low temperature. This is advantageous for keeping the temperature of the pump chamber high while keeping the temperature of the lubricating oil reservoir low. On the other hand, since the cooling housing close to the lubricating oil reservoir is made of a material having a higher heat transfer coefficient than the side housing, the lubricating oil stored in the lubricating oil reservoir is used as a cooling passage for the cooling housing. It can be cooled by the refrigerant. Therefore, the temperature of the lubricating oil stored in the lubricating oil storage section can be kept low, which is advantageous for suppressing deterioration of the lubricating oil. Further, since the vaporization of the lubricating oil can be suppressed, it is advantageous for making the pump chamber oil-free.

  According to the dry pump according to aspect 5, since the side housing is formed using an iron-nickel alloy as a base material, it is possible to ensure corrosion resistance while reducing the heat transfer coefficient of the side housing. Therefore, it is suitable when the gas exhausted by the dry pump is corrosive.

The dry pump according to aspect 6 has a housing body having a pump chamber and an intake port and an exhaust port communicating with the pump chamber, a rotating shaft installed in the housing body, and a pump chamber that is integrated with the rotating shaft. A dry rotor comprising a rotor rotating member that is composed of a rotor disposed and that compresses the gas sucked from the intake port as it rotates and exhausts it from the exhaust port; and a lubricating oil reservoir that is disposed in the housing body and stores lubricating oil. In the pump,
The housing body includes a pump housing having a pump chamber, and a side housing attached to at least one end of both ends of the pump housing, and the side housing is provided between the pump chamber and the lubricating oil reservoir. And a heat-insulating intermediate chamber, and a cooling passage that is formed between the pump chamber and the lubricating oil reservoir and allows the refrigerant to pass therethrough.

  In this case, since a hollow intermediate chamber for heat insulation is formed between the pump chamber and the lubricating oil reservoir, heat transfer from the pump chamber to the lubricating oil reservoir can be suppressed. The lubricating oil stored in the storage part can be efficiently cooled by the refrigerant in the cooling passage of the cooling housing. Therefore, the temperature of the lubricating oil stored in the lubricating oil storage section can be kept low, which is advantageous for suppressing deterioration of the lubricating oil. Further, since the vaporization of the lubricating oil can be suppressed, it is advantageous for making the pump chamber oil-free.

  According to the dry pump according to aspect 7, the side housing is based on a material whose heat transfer coefficient is lower than that of the cooling housing, and the cooling housing is based on a material whose heat transfer coefficient is higher than that of the side housing. Features. The side housing near the pump chamber that you want to maintain at a high temperature is based on a material that has a lower heat transfer coefficient than the cooling housing, so heat transfer from the pump chamber that you want to maintain at a high temperature to the lubricating oil reservoir that you want to maintain at a low temperature This is advantageous for keeping the temperature of the pump chamber high while lowering the temperature of the lubricating oil reservoir. On the other hand, the cooling housing close to the lubricating oil housing that is desired to be maintained at a low temperature is based on a material having a higher heat transfer coefficient than the side housing. For this reason, the lubricating oil stored in the lubricating oil reservoir can be efficiently cooled by the refrigerant in the cooling passage of the cooling housing. Therefore, the temperature of the lubricating oil stored in the lubricating oil reservoir can be kept low, which is advantageous for suppressing deterioration of the lubricating oil and extending the life of the lubricating oil. Further, since the vaporization of the lubricating oil can be suppressed, it is advantageous for making the pump chamber oil-free.

  According to the dry pump according to aspect 8, at least one of the pump housing and the side housing is based on a material having a heat transfer coefficient of 15 W / m · K or less, and heat transferability is suppressed. Features. In this case, heat transfer from the pump chamber can be suppressed, which is advantageous for maintaining the temperature of the pump chamber at a high temperature.

According to the dry pump according to aspect 9, at least one of the rotating shaft, the pump housing, and the side housing is formed using a material having a linear expansion coefficient of 6 × 10 ⁻⁶ m / m · K or less as a base material. The thermal expansibility is suppressed. Even if the temperature of the pump chamber is maintained at a high temperature, an increase in the gap due to thermal expansion can be suppressed, which is advantageous in suppressing a back flow of gas through the gap.

  According to the dry pump according to aspect 10, a plurality of pump chambers are arranged side by side along the axial length direction of the rotating shaft, and a plurality of rotors of the rotor rotating member are arranged side by side along the axial length direction of the rotating shaft. It is characterized by being rotatably arranged in each pump chamber. For this reason, gas can be compressed in each pump chamber, respectively, and the exhaust property of gas can be improved.

  According to the present invention, it is advantageous to keep the temperature of the lubricating oil in the lubricating oil reservoir low while keeping the temperature of the pump chamber high so as to be suitable for exhausting gas such as sublimation gas or condensable gas. A dry pump can be provided. Therefore, it is advantageous for suppressing the deterioration of the lubricating oil and extending the life of the lubricating oil. Further, the vaporization of the lubricating oil can be suppressed, and the vaporized lubricating oil can be prevented from entering the pump chamber, which is advantageous for making the pump chamber oil-free.

(Embodiment 1)
A representative embodiment of the present invention will be described with reference to FIGS. This embodiment is a case where it is applied to a multistage dry pump. FIG. 1 is a sectional view taken along the axial length direction of a multistage dry pump. FIG. 2 is a sectional view taken along line II-II in FIG. FIG. 3 shows a perspective view of the cooling housing. FIG. 4 is a conceptual perspective view schematically showing the internal structure of the multistage dry pump.

  In FIG. 1, reference numeral 1 denotes a multistage dry pump. The housing body 1x of the multistage dry pump 1 is attached to both ends of the pump housings 2, 2 'having the pump chambers 8, 9, 10, 11 and separated in the vertical direction and the lengths of the pump housings 2, 2'. Side housings 22 and 23 having a flat plate shape, and a cooling housing 29 having a flat plate shape attached to the side housing 23 opposite to the pump housings 2 and 2 ′ are provided. Further, on the opposite side of the cooling housing 29 to the pump housings 2 and 2 ′, a lubricating oil housing 31 having a lubricating oil chamber 33 as a lubricating oil reservoir is provided. In the present specification, the superscript “′” means a pair.

  As shown in FIG. 1, in the pump housing 2, 2 ′, a first stage pump chamber 8, a second stage pump chamber 9, and a third stage pump partitioned by partition walls 5, 6, 7. A plurality (four) of pump chambers 10 and a fourth-stage pump chamber 11 are formed. Such four pump chambers 8, 9, 10, 11 are arranged in one direction in this order from the intake port 3 to the exhaust port 4 of the dry pump 1.

  In the upper pump housing 2, the intake port 3 communicating with the target chamber 90 in the multistage dry pump 1 is formed so as to communicate with the intake port 8 x of the first-stage pump chamber 8. In the lower pump housing 2 ′, the exhaust port 4 communicating with the atmosphere is formed so as to communicate with the exhaust port 11 x of the fourth-stage pump chamber 11.

  As shown in FIG. 1, the pump housings 2, 2 ′ extend along the axial length direction of the built-in rotary shafts 16, 16 ′. One rotary shaft 16 is connected to a motor 20 as a drive unit to serve as a drive shaft. The other rotating shaft 16 ′ is not connected to the motor 20 and is a driven shaft. As is well known, although the internal structure of the motor 20 is not shown, a stator motor is formed of a mold material such as unsaturated polyester, or a so-called separator is provided in the gap between the stator and the rotor. Airtightness is maintained by a canned motor.

  As shown in FIGS. 1 and 4, timing gears 21, 21 ′ are attached to the shaft ends of the rotating shafts 16, 16 ′ installed on the housing main body 1 x. The pair of rotating shafts 16 and 16 'are interlocked with each other via the timing gears 21 and 21' and rotate in opposite directions.

  As can be understood from FIG. 4, the pair of first-stage rotors 12, 12 ′ in the shape of a pair attached to the two pairs of rotating shafts 16, 16 ′ are rotatable in the first-stage pump chamber 8. Is arranged. Similarly, two pairs of second-stage rotors 13 and 13 ′ having a template shape attached to the rotary shafts 16 and 16 ′ are rotatably disposed in the second-stage pump chamber 9. As shown in FIGS. 2 and 4, two pairs of third stage rotors 14 and 14 ′ having a template shape attached to two pairs of rotating shafts 16 and 16 ′ are rotatable to the third stage. Arranged in the eye pump chamber 10. Similarly, two pairs of fourth-stage rotors 15 and 15 ′ in the shape of a pair attached to two pairs of rotating shafts 16 and 16 ′ are rotatably disposed in the fourth-stage pump chamber 11. .

  One rotor rotating member 34 is formed of a rotating shaft 16 and rotors 12, 13, 14, 15 arranged in parallel along the axial length direction. The other rotor rotating member 34 ′ is formed of a rotating shaft 16 ′ and rotors 12 ′, 13 ′, 14 ′, and 15 ′ arranged side by side along the axial length direction.

  As shown in FIG. 1, the pump chambers 8, 9 adjacent to each other in the axial direction of the rotary shafts 16, 16 ′ are communicated with each other through a gas transfer passage 17. The pump chambers 9, 10 adjacent to each other in the axial direction of the rotary shafts 16, 16 ′ are communicated with each other through a gas transfer passage 18. The pump chambers 10 and 11 that are adjacent to each other in the axial direction of the rotary shafts 16 and 16 ′ are communicated with each other through a gas transfer passage 19. As a result, the gas sucked in the direction of the arrow A1 from the intake port 3 is compressed in four stages and exhausted from the exhaust port 4 in the direction of the arrow A2.

  As can be understood from FIG. 2, the two pairs of rotors 14 and 14 'rotate in reverse to each other, and intake and exhaust are performed in the pump chamber 10 in which the rotors 14 and 14' are accommodated. Similarly, the two pairs of rotors 12 and 12 ′ attached to the rotary shafts 16 and 16 ′ rotate in the opposite directions so that intake and exhaust are performed in the pump chamber 8 that houses the rotors 12 and 12 ′. It has become. Similarly, the two pairs of rotors 13 and 13 ′ attached to the rotary shafts 16 and 16 ′ rotate in the opposite directions so that intake and exhaust are performed in the pump chamber 9 in which the rotors 13 and 13 ′ are accommodated. It has become. Further, the two pairs of rotors 15 and 15 ′ attached to the rotary shafts 16 and 16 ′ rotate in reverse directions so that intake and exhaust are performed in the pump chamber 11 that accommodates the rotors 15 and 15 ′. Yes.

  In FIG. 2, a slight gap is formed between the two pairs of rotors 14 and 14 ', and the rotors 14 and 14' are arranged so as not to contact each other. The two pairs of rotors 14, 14 ′ are arranged so that a slight gap is formed between the outer wall surface of the rotors 14, 14 ′ and the inner wall surface of the pump chamber 10 and are not in contact with each other. Yes. The same applies to the other two pairs of rotors 12, 12 ', the two pairs of rotors 13, 13', and the two pairs of rotors 15, 15 '.

  A description will be given of the pump chamber volume. As can be understood from FIG. 1, the pump chambers 8, 9, 10, and 11 are set to be smaller in order, the volume of the first-stage pump chamber 8 on the intake port 3 side is the largest, and the fourth on the exhaust port 4 side. The volume of the stage pump chamber 11 is the smallest. Accordingly, the axial length of the pump chamber is set to be smaller in the order of the pump chambers 8, 9, 10, and 11, and the axial length size of the first stage pump chamber 8 on the intake port 3 side is the largest, and the exhaust port The axial length size of the fourth side fourth-stage pump chamber 11 is the smallest.

  This is mainly due to the following reason. That is, the pressure difference between the suction side and the discharge side increases in the order of the pump chambers 8, 9, 10, and 11. That is, in the pump chamber 11 on the downstream side, the pressure difference between the suction side and the discharge side is larger than that of the other pump chambers 8, 9, and 10. For this reason, the compression work of the fourth stage pump chamber 11 on the exhaust port 4 side is the largest, the compression heat generated in the fourth stage pump chamber 11 is the largest, and the fourth stage pump chamber 11 on the exhaust port 4 side. Is higher than the temperatures of the other pump chambers 8, 9, and 10. That is, the compression work generally increases as it goes to the exhaust port 4, and the compression work in the atmosphere side, the third pump chamber 10 and the fourth stage pump chamber 11 occupies most of the entire pump. Most of the compression heat is generated in the third and fourth stage pump chambers 10 and 11. Therefore, as described above, the pump chamber volumes of the pump chambers 8, 9, 10, and 11 are reduced toward the downstream, and the first-stage pump chamber 8 on the intake port 3 side and the fourth-stage pump on the exhaust port 4 side are reduced. The difference in compression work with the chamber 11 is prevented from becoming excessively large. As a result, the difference in compression heat between the first stage pump chamber 8 and the fourth stage pump chamber 11 does not become excessively large.

  As shown in FIG. 1, the side housing 23 is formed with a flat, heat-insulating intermediate chamber 26 having a hollow shape. The intermediate chamber 26 is formed between the pump chamber 11 that is desired to be maintained at a high temperature and the lubricating oil chamber 33 that is desired to be maintained at a low temperature. Since the intermediate chamber 26 has a hollow shape and functions as a heat insulating space, heat transfer from the pump chamber 11 desired to be maintained at a high temperature to the lubricating oil chamber 33 desired to be maintained at a low temperature can be suppressed, which further contributes to weight reduction. it can.

  The cooling housing 29 is attached in contact with the surface 23f of the side housing 23, and is formed of a good heat transfer material having higher heat transferability than the side housing 23, such as a copper-based material or an aluminum-based material. And has an insertion hole 16s through which the rotation shafts 16 and 16 'are inserted. In the cooling housing 29, a cooling passage 30 through which a refrigerant (generally cooling water) passes is formed in the vicinity of the lubricating oil chamber 33 so as to face the lubricating oil chamber 33. The cooling passage 30 is located on the lower side of the pump housings 2, 2 ′.

  As shown in FIG. 1, the cooling passage 30 is formed between the pump chamber 11 of the high temperature side pump housing 2, 2 ′ and the lubricating oil chamber 33 of the low temperature side lubricating oil housing 31. The cooling passage 30 is formed in a flat plate-shaped cooling housing 29 by drill drilling or insert pipe casting, and the cooling housing 29 can be cooled when cooling water as a coolant is passed through the cooling passage 30. It has become. In FIG. 3, the cooling passage 30 is formed in a shape in which both end surfaces 29 m and 29 n of the outer surface of the cooling housing 29 are communicated in a straight shape at the lower portion 29 u of the cooling housing 29. It can also be set as the shape bent like.

  As shown in FIG. 1, the pump housings 2 and 2 ′ are integrated with the side housing 22 on the intake port 3 side, and are integrated with the side housing 23 on the exhaust port 4 side. In the side housing 22 on the intake port 3 side, ring-shaped bearings 24 and 24 ′ on the intake port 3 side and ring-shaped seal members 27 and 27 ′ are provided on the outer peripheral portion of the rotary shafts 16 and 16 ′. . As shown in FIG. 1, ring-shaped seal members 27 and 27 ′ are located on the side close to the pump chamber 8. The bearings 24 and 24 ′ are positioned farther from the pump chamber 8 than the seal members 27 and 27 ′. This is for the purpose of enhancing the protection of the bearings 24 and 24 ′ against heat of the pump chamber 8 and corrosive gas.

  Similarly, as shown in FIG. 1, seal members 28 and 28 ′ and bearings 25 and 25 ′ are provided on the outer peripheral portion of the rotary shafts 16 and 16 ′ in the side housing 23 on the exhaust port 4 side. The seal members 28, 28 ′ are provided on the outer peripheral surface of the rotary shafts 16, 16 ′ in the side housing 23, and have a sealing function that prevents the lubricating oil 32 in the lubricating oil chamber 33 from entering the pump chamber 11 side. Fulfill. Therefore, the pump chambers 8, 9, 10, and 11 are maintained with an oil-free state as a target.

  According to the present embodiment, the seal members 28 and 28 ′ are located on the side close to the pump chamber 11. The bearings 25 and 25 ′ are positioned farther from the pump chamber 11 than the seal members 28 and 28 ′. This is to improve the protection of the bearings 25 and 25 'against heat of the pump chamber 11 and corrosive gas. Note that both ends of one rotary shaft 16 are rotatably supported by bearings 24 and 25. Both ends of the other rotary shaft 16 'are rotatably supported by bearings 24' and 25 '.

  As shown in FIG. 1, as described above, the cooling housing 29 is provided so as to be in contact with the surface 23f of the side housing 23 adjacent to the pump chamber 11 that is desired to be maintained at a high temperature. Further, on the opposite side of the cooling housing 29 to the side housing 23, a lubricating oil housing 31 having a lid shape is attached in contact with the cooling housing 29.

  Timing gears 21 and 21 'are accommodated in the lubricating oil chamber 33 of the lubricating oil housing 31, and the lubricating oil chamber 33 faces the bearings 25 and 25'. As shown in FIG. 1, since at least a part of the timing gears 21 and 21 ′ is immersed in the lubricating oil 32 in the lubricating oil chamber 33, the lubricating oil in the lubricating oil chamber 33 is rotated when the timing gears 21 and 21 ′ are rotated. 32 is applied to the timing gears 21 and 21 ′ and the bearings 25 and 25 ′, and the lubricity and cooling performance thereof are ensured.

  As described above, the temperature of the fourth-stage pump chamber 11 is higher than the temperatures of the other pump chambers 8, 9, and 10. Thus, the rotors 15 and 15 ′ arranged in the fourth stage pump chamber 11 that becomes high temperature are the rotors 12, 12 ′, 13, and 13 arranged in the other pump chambers 8, 9, and 10. Since it is thinner than ', 14, 14' and has a smaller axial length, it is advantageous for suppressing the thermal expansion of the rotors 15, 15 'that are desired to be maintained at a high temperature.

  Further, according to the present embodiment, as shown in FIG. 1, the high temperature is maintained in the side housing 23 on the exhaust port 4 side where the rotary shafts 16 and 16 ′ are supported by the bearings 25 and 25 ′ on the exhaust port 4 side. The seal rings 28 and 28 ', the heat insulating intermediate chamber 26, the bearings 25 and 25', the cooling passage 30, the lubrication are sequentially performed in the direction from the fourth stage pump chamber 11 desired to the lubricating oil housing 31 to be maintained at a low temperature. An oil chamber 33 is provided. As shown in FIG. 1, the seal members 28, 28 ′ are closer to the pump chamber 11 than the intermediate chamber 26, the bearings 25, 25 ′, the cooling passage 30, and the lubricating oil chamber 33. Intrusion into the bearings 25, 25 ′, the cooling passage 30, and the lubricating oil chamber 33 can be suppressed. Therefore, when the gas is corrosive, the intermediate chamber 26, the bearings 25 and 25 ', the cooling passage 30, the lubricating oil chamber 33, and the like can be protected from the corrosive gas. In particular, when the gas has condensability or sublimability, the gas having condensability or sublimation enters the intermediate chamber 26, the bearings 25, 25 ', the cooling passage 30, the lubricating oil chamber 33, etc. Liquefaction and solidification can be suppressed.

  According to this embodiment, the intermediate chamber 26 for heat insulation is provided in the side housing 23 between the seal members 28 and 28 ′ and the bearings 25 and 25 ′. Thereby, although the temperature of the pump chamber 11 is kept high, heat transfer from the pump chamber 11 on the high temperature side to the bearings 25 and 25 ′ can be suppressed, and overheating of the bearings 25 and 25 ′ is further suppressed. be able to. Further, the bearings 25 and 25 ′ also face the lubricating oil chamber 33, and the lubricating oil 32 in the lubricating oil chamber 33 is applied to the bearings 25 and 25 ′ by the rotation of the timing gears 21 and 21 ′. For this reason, overheating of the bearings 25 and 25 ′ can be further suppressed, and the bearing performance of the bearings 25 and 25 ′ is ensured satisfactorily while maintaining the inside of the pump chamber 11 at a high temperature.

  When the multistage dry pump 1 is used, the exhausted gas in the target chamber 90 is sucked in the direction of the arrow A1 from the inlet 3 of the pump housing 2. When the pump is operated, a pair of rotor rotating members 34 and 34 ′ carrying the rotors 12, 12 ′, 13, 13 ′, 14, 14 ′, 15, 15 ′ on the rotating shafts 16, 16 ′ are connected to the motor 20. Are rotated in opposite directions.

  Then, the gas sucked in the direction of the arrow A <b> 1 from the intake port 3 is first compressed in the first stage pump chamber 8 and transferred to the second stage pump chamber 9 through the gas transfer passage 17. Further, the gas compressed in the second stage pump chamber 9 is transferred to the third stage pump chamber 10 via the gas transfer passage 18. Further, the gas compressed in the third stage pump chamber 10 is transferred to the fourth stage pump chamber 11 through the gas transfer passage 19. The gas thus compressed is finally discharged from the exhaust port 4 to the outside of the multistage dry pump 1 (atmosphere side) in the arrow A2 direction.

  At this time, since the gas is compressed in each of the pump chambers 8, 9, 10, and 11, compression heat is generated. For this reason, the temperature of the rotor rotating members 34, 34 'and the pump housings 2, 2' rises. Of course, the multi-stage dry pump 1 is cooled from the outside of the multi-stage dry pump 1 by an appropriate water cooling or air cooling device. It is preferable to pass the inside of the multistage dry pump 1 in the form of gas so that it does not liquefy or solidify. Therefore, as described above, it is preferable to keep the inside of the pump as high as possible.

  In this respect, according to the present embodiment, as shown in FIG. 1, in the side housing 23 on the exhaust port 4 side, the intermediate chamber 26 for heat insulation, which is hollow, is to be maintained at a higher temperature. It is formed between the lubricating oil chamber 33 to be maintained at a lower temperature. For this reason, it is possible to suppress heat transfer from the high temperature side fourth stage pump chamber 11 side toward the cooling housing 29 side to be maintained at a low temperature. For this reason, the temperature of the fourth stage pump chamber 11 can be maintained high while lowering the temperature of the lubricating oil chamber 33, the temperature of the side housing 23 on the exhaust port 4 side, and the temperature gradient of the cooling housing 29 are further increased, It is advantageous to keep the temperature inside the pump at a higher temperature. For this reason, liquefaction or solidification of gas, such as condensable gas and sublimation gas, can be suppressed.

  Thus, since the temperature of each pump chamber can be kept high compared with the conventional pump, when exhausting gas, such as a condensable gas and a sublimation gas, using the multistage dry pump 1, the pump housings 2 and 2 'It is advantageous to avoid liquefaction or solidification within. Therefore, it is possible to prevent the smooth rotation of the rotors 12, 13, 14, 15 and the rotors 12 ', 13', 14 ', 15' from being impaired due to liquefaction or solidification of condensable gas or sublimable gas. be able to. Therefore, it is possible to realize a multi-stage dry pump with further improved durability against condensable gas and sublimable gas.

  In addition to the heat transfer from the pump chamber 11 side, the lubricating oil stored in the lubricating oil housing 31 is also caused by mechanical loss generated from the bearings 25 and 25 ′ and the timing gears 20 and 21 ′ as the pump rotates. Resulting in a temperature rise of 32. In this respect, according to the present embodiment, the cooling passage 30 through which the refrigerant (generally cooling water) passes is formed between the pump chamber 11 and the lubricating oil chamber 33, so that the lubricating oil in the lubricating oil chamber 33 can be obtained. This is advantageous for maintaining the temperature of 32 low, is advantageous for suppressing deterioration of the lubricating oil 32, and allows the multistage dry pump 1 to operate well over a long period of time. Further, since the temperature of the lubricating oil 32 in the lubricating oil chamber 33 can be kept low by the cooling housing 29 having the cooling passage 30, the vaporization of the lubricating oil 32 can be suppressed, and the vaporized lubricating oil is supplied to the pump chambers 8, 9. 10 and 11 can be suppressed, which is advantageous for maintaining the pump chambers 8, 9, 10, and 11 in an oil-free state.

  In particular, since the intermediate chamber 26 for heat insulation and the cooling passage 30 for cooling are formed in this order from the pump chamber 11 of the pump housing 2, 2 ′ toward the lubricating oil chamber 33 of the lubricating oil housing 31, the pump chamber is formed. 11 is advantageous for keeping the temperature of the lubricating oil 32 in the lubricating oil chamber 33 low while keeping the temperature inside the cylinder 11 high.

  Further, as shown in FIG. 1, the lubricating oil housing 31 having the lubricating oil chamber 33 for holding the lubricating oil 32 is in direct contact with the cooling housing 29 and is directly cooled by the cooling housing 29. It is advantageous to maintain 32 at a low temperature. In particular, as shown in FIG. 1, the lubricating oil 32 itself stored in the lubricating oil chamber 33 of the lubricating oil housing 31 is cooled by directly contacting the surface 29w (see FIG. 1) of the cooling housing 29. Therefore, it is more advantageous for cooling the lubricating oil 32 stored in the lubricating oil housing 31.

  According to this embodiment, the compression work generally increases as it goes to the exhaust port side. In particular, the compression work in the atmosphere side, in this embodiment, the third-stage pump chamber 10 and the fourth-stage pump chamber 11 occurs. Since most of this pump is occupied, most of the compression heat is generated in the third and fourth stage pump chambers 11.

  That is, since the compression heat generated inside the pump is cooled in order by the above heat transfer, the temperature sequentially decreases in the order of the fourth stage pump chamber 11, the side housing 23 on the exhaust port 4 side, and the cooling housing 29. However, according to this embodiment, the fourth stage pump chamber 11 side of the pump housings 2, 2 ′ is indirectly connected by the cooling housing 29 with the side housing 23 on the exhaust port 4 side interposed. Therefore, the pump temperature of the fourth stage pump chamber 11 can be kept high.

  Further, when it is necessary to keep the inside of the pump at a higher temperature, it is preferable to further increase the temperature gradient between the high temperature side pump housings 2, 2 ′ and the low temperature side cooling housing 29. Therefore, the side housing 23 interposed between the pump housings 2, 2 ′ and the cooling housing 29 can be formed of a material having low heat transfer properties. In this case, the side housing 23 can be formed using a material having a heat transfer coefficient of 20 W / m · k or less, or 15 W / m · k or less. Therefore, the side housing 23 can be formed of a material having a low heat transfer coefficient, for example, a nickel-rich iron-nickel alloy. In particular, it can be formed of nickel-rich austenitic material (for example, austenitic cast iron). In this case, the side housing 23 can also be formed of austenitic spheroidal graphite cast iron among austenitic cast iron having a small heat transfer coefficient. In general, spheroidal graphite cast iron is not only flake graphite cast iron, but also has high strength and good corrosion resistance as well as a low heat transfer coefficient even at the same base.

  As described above, when the multi-stage dry pump 1 is operated with the pump chambers 8 to 11 kept at a high temperature, the pump housings 2, 2 ′ and the rotor rotating members 34, 34 ′ are thermally expanded. In particular, in the case of the multistage dry pump 1, the rotor rotating member 34 is larger than the distance R (see FIG. 2) in the major axis direction of the rotors 12, 13, 14, 15, 12 ′, 13 ′, 14 ′, 15 ′. , 34 ′ have a considerably large length in the axial direction of the rotary shafts 16, 16 ′, and therefore, the rotor lock tends to occur easily based on the thermal expansion in the axial length direction. In this regard, according to the present embodiment, the rotary shafts 16 and 16 'are made of a metal material having a small linear expansion coefficient, specifically, a nickel-rich austenitic material (for example, austenitic cast iron). , 16 ′ is designed to reduce the influence of thermal expansion. As a result, even if the dry pump 1 is operated so that the temperature inside the pump becomes high, the thermal expansion of the rotary shafts 16 and 16 'can be suppressed. Further, thermal strain generated between the rotary shaft 16 and the rotors 12, 13, 14, and 15 due to thermal expansion, and the rotary shaft 16 'and the rotors 12', 13 ', 14', and 15 'caused by thermal expansion It is possible to reduce the influence of thermal strain generated between the two. As a result, the occurrence of rotor lock due to thermal expansion can be suppressed.

In this embodiment, pump constituent materials such as pump housings 2, 2 'and side housings 22, 23 are formed of a general material such as spheroidal graphite cast iron or flake graphite cast iron. In order to secure a minute gap between the housing and the housing in the entire temperature range from room temperature to high temperature, the constituent materials of the pump housings such as the pump housings 2, 2 ′ and the side housings 22, 23 have a linear expansion coefficient of 6 ×. It can be 10 ⁻⁶ m / m · K or less (300 K), in particular 4 × 10 ⁻⁶ m / m · K or less (300 K).

  The temperature of the fourth stage pump chamber 11, the temperature of the side housing 23 on the exhaust port 4 side, and the temperature of the cooling housing 29 have a temperature gradient that decreases in this order as described above. Needless to say, if the constituent material is a material having a low heat transfer coefficient, such as an iron-nickel alloy typified by austenitic cast iron, stainless steel, or the like, the temperature gradient can be further increased.

  In order to reduce the linear expansion coefficient of the rotating shafts 16 and 16 ', the base material of the rotating shafts 16 and 16' can be made of, for example, an iron-nickel alloy.

  According to the iron-nickel alloy, the nickel content greatly affects the linear expansion coefficient. In this case, nickel may be 10 to 50%, 15 to 45%, 20 to 40%, 34 to 40%, or the like. Examples of the iron-nickel alloy include a nickel-rich austenitic material (for example, austenitic cast iron), an invar alloy (nickel: about 32 to 39% by weight), and a super invar alloy (nickel: about 30 to about 30 to 30% by weight). 34 wt%, cobalt about 2 to 8 wt%).

Invar alloy can have a linear expansion coefficient of 1.5 × 10 ⁻⁶ m / m · K or less, for example. In the case of Super Invar alloy, the linear expansion coefficient can be, for example, 1.5 × 10 ⁻⁷ m / m · K or less. As a result, the rotary shafts 16 and 16 ′ are installed in the pump chambers 8, 9, 10, and 11, so that the axial length is long, but thermal expansion in the axial direction is suppressed.

Further, the pump housings 2 and 2 ′ have a linear expansion coefficient of 6 × 10 ⁻⁶ m / m · K or less, particularly 4 × 10 ⁻⁶ m / m · K or less, like the rotary shafts 16 and 16 ′. The form currently formed with the material which is hard to thermally expand can be illustrated. Specifically, the form currently formed with the austenitic material (for example, austenitic cast iron, stainless steel) of nickel rich (nickel: 15 to 45 weight%) can be illustrated. The austenitic cast iron described above may be spheroidal graphite cast iron or flake graphite cast iron, but spheroidal graphite cast iron is more advantageous for improving corrosion resistance, reducing heat transfer coefficient, increasing strength, and the like.

  Further, according to the present embodiment, the rotors 12, 13, 14, and 15 carried on the outer peripheral portion of the one rotary shaft 16 are made of aluminum or aluminum alloy, flake graphite cast iron, spheroidal graphite cast iron, potato having good workability. It is formed of a metal material such as worm-like graphite cast iron, eutectic graphite cast iron, or carbon steel. Similarly, the rotors 12 ', 13', 14 ', 15' carried on the outer peripheral portion of the other rotating shaft 16 'are made of aluminum or aluminum alloy, flake graphite cast iron, spheroidal graphite cast iron, potato having good workability. It is formed of a metal material such as worm-like graphite cast iron, eutectic graphite cast iron, or carbon steel.

  In this case, the rotor 12, 13, 14, 15 is integrally cast around the outer periphery of the rotating shaft 16 in the axial direction of the rotating shaft 16, or brazed to the outer peripheral portion of the rotating shaft 16, or One rotor initial member is configured by joining by a joining technique such as press fitting (including shrink fitting and cold fitting). The rotors 12, 13, 14, and 15 are in the same phase in the circumferential direction.

  Similarly, the rotors 12 ′, 13 ′, 14 ′, and 15 ′ are integrally cast on the outer peripheral portion of the rotary shaft 16 ′ in the axial direction of the rotary shaft 16 ′, or are arranged on the outer peripheral portion of the rotary shaft 16 ′. The other rotor initial member is configured by brazing or joining by a joining technique such as press fitting (including shrink fitting and cold fitting). The rotors 12 ', 13', 14 ', 15' are in phase in the circumferential direction.

  By cutting one rotor initial member having such a rotary shaft 16, multiple stages (four stages) of rotors 12, 13, 14, 15 arranged in parallel in the axial direction of the rotary shaft 16 are integrated. One rotor rotating member 34 assembled together is formed. Similarly, by cutting the other rotor initial member having the rotation shaft 16 ′, the rotation shaft 16 ′ and the multiple stages (four stages) of the rotors 12 ′, 13 ′, 14 ′, 15 ′ are integrated. The other assembled rotor rotating member 34 'is formed.

(Embodiment 2)
FIG. 5 shows a second embodiment. This embodiment has basically the same configuration as the above-described embodiment, and has the same effects. Hereinafter, a description will be given centering on parts different from the first embodiment. As shown in FIG. 5, the housing main body 1x of the multi-stage dry pump 1 has pump housings 2, 2 'having pump chambers 8, 9, 10, 11 separated on the upper and lower sides, and both ends of the pump housings 2, 2'. Side housings 22 and 23 are provided. Furthermore, a lubricating oil housing 31 is attached to the side housing 23 on the side opposite to the pump housings 2, 2 ′. Note that the cooling housing 29 used in the first embodiment is not provided.

  Inside the side housing 23, a hollow heat insulation intermediate chamber 26 is formed. The intermediate chamber 26 is formed between the pump chamber 11 of the high temperature side pump housing 2, 2 ′ and the lubricating oil chamber 33 of the low temperature side lubricating oil housing 31. As a result, heat can be prevented from being transferred from the high temperature side pump chamber 11 to the lubricating oil chamber 33 of the low temperature side lubricating oil housing 31. Further, a cooling passage 30 through which the refrigerant passes is formed in the vicinity of the lubricating oil chamber 33 inside the side housing 23.

  In other words, as shown in FIG. 5, the intermediate chamber 26 and the cooling passage 30 are formed in this order from the pump chamber 11 that is desired to be maintained at a high temperature toward the lubricating oil chamber 33 that is desired to be maintained at a low temperature. For this reason, it is advantageous to keep the temperature of the lubricating oil 32 in the lubricating oil chamber 33 low while maintaining the inside of the pump chamber 11 at a high temperature.

  Therefore, also in the present embodiment, in the same manner as in the first embodiment, the temperature inside the pump is kept high so as to be suitable for exhaustion of condensable gas and sublimation gas, and the lubricating oil chamber 33 of the lubricating oil housing 31 is maintained. Cooling of the stored lubricating oil 32 can be performed well, which is advantageous for maintaining the lubricating oil 32 below the allowable temperature.

  Further, when it is necessary to keep the inside of the pump at a higher temperature, it is preferable to further increase the temperature gradient between the cooling housing 29 and the pump housings 2, 2 ′. Therefore, the side housing 23 positioned between the high temperature side pump housings 2, 2 ′ and the low temperature side lubricant housing 31 has a heat transfer coefficient of 20 W / m · k or less, or 15 W / m · k or less. It can also be formed of a material having a low transmission rate. Examples of such a material include iron-nickel alloys such as austenitic cast iron in consideration of corrosion resistance. In particular, among austenitic cast iron, austenitic spheroidal graphite cast iron having both a low heat transfer coefficient and a rhetsu expansion coefficient can be exemplified.

(Embodiment 3)
FIG. 6 shows a third embodiment. This embodiment has basically the same configuration as the above-described embodiment, and has the same effects. Hereinafter, a description will be given centering on parts different from the first embodiment. As shown in FIG. 6, the housing body 1x of the multi-stage dry pump 1 includes a pump housing 2, 2 ′ having a pump chamber and a side housing 22 attached to both ends of the pump housings 2, 2 ′. 23, and a cooling housing 29 provided on the side housing 23 on the opposite side to the pump housings 2, 2 ′. Further, a lubricating oil housing 31 is attached to the cooling housing 29 on the side opposite to the side housing 23.

  Unlike the first embodiment, the side housing 23 is not formed with a hollow heat insulating intermediate chamber 26. Therefore, in order to reduce the heat transfer performance of the side housing 23, the side housing 23 can be formed of a material having a heat transfer coefficient of 20 W / m · k or less, or 15 W / m · k or less. Examples of such a material include iron-nickel alloys such as austenitic cast iron in consideration of corrosion resistance. In particular, among austenitic cast iron, austenitic spheroidal graphite cast iron having both a small heat transfer coefficient and a linear expansion coefficient can be exemplified.

  Also in this embodiment, as shown in FIG. 6, as in the first embodiment, the intermediate chamber 26 and the cooling passage 30 are formed in this order from the high temperature side pump chamber 11 toward the low temperature side lubricating oil chamber 33. Therefore, it is advantageous to keep the temperature of the lubricating oil 32 in the lubricating oil chamber 33 of the lubricating oil housing 31 low while keeping the inside of the pump at a high temperature. Therefore, similarly to the first embodiment, the lubricating oil 32 of the lubricating oil housing 31 can be cooled well while maintaining the pump temperature high so as to be suitable for exhausting gases such as condensable gas and sublimable gas. This is advantageous for maintaining the lubricating oil 32 below the allowable temperature.

(Embodiment 4)
FIG. 7 shows a fourth embodiment. This embodiment has basically the same configuration as the above-described embodiment, and has the same effects. Hereinafter, a description will be given centering on parts different from the first embodiment. As shown in FIG. 7, the intermediate chamber 26 formed in the side housing 23 is in communication with a passage 80, and normal temperature or cooled gas (nitrogen or the like) is supplied to the intermediate chamber 26 through the passage 80. . Thereby, the cooling property of the lubricating oil 32 of the lubricating oil housing 31 can be ensured. The gas can flow into the pump chamber 11 through the seal members 28 and 28 ′ and be discharged from the exhaust port 4. In this case, it is preferable to appropriately select the sealing force and the sealing structure of the sealing members 28 and 28 '.

(Other)
According to the above-described embodiment, the present invention is applied when exhausting condensable gas and sublimable gas. However, the present invention is not limited thereto, and is applied when exhausting other gases other than condensable gas and sublimable gas. May be. According to the above-described embodiment, the cooling housing 29 and the lubricating oil housing 31 are separately connected to each other by a mounting tool such as a screw (not shown). However, the cooling housing 29 and the lubricating oil housing are not limited thereto. 31 may be integrally formed. In this case, the cooling housing 29 and the lubricating oil housing 31 may be formed of copper or aluminum, or may be formed of other materials. Although the above-described embodiment is applied to a multistage dry pump, a single-stage dry pump may be used. The pump housings 2 and 2 ′ and the rotary shafts 16 and 16 ′ can have a linear expansion coefficient of 0 (including 0 or more). In addition, the present invention is not limited only to the embodiment described above and shown in the drawings, and can be implemented with appropriate modifications as necessary without departing from the scope of the invention.

  In the present invention, for example, in processes such as CVD and dry etching, such as semiconductor processes and liquid crystal processes, when a gas such as a condensable gas or a sublimable gas is exhausted, the pump is operated by liquefying or solidifying inside the pump. It can be used for a dry pump that does not cause trouble.

It is sectional drawing cut | disconnected along the axial length direction of the multistage dry pump. It is sectional drawing along the II-II line of FIG. It is a perspective view of a cooling housing having a cooling passage. It is a conceptual perspective view which represents typically the internal structure of a multistage dry pump. FIG. 6 is a cross-sectional view taken along the axial length direction of the multistage dry pump according to the second embodiment. It is sectional drawing cut | disconnected along the axial length direction of a multistage dry pump concerning Embodiment 3. FIG. FIG. 10 is a cross-sectional view taken along the axial length direction of the multistage dry pump according to the fourth embodiment.

Explanation of symbols

  In the figure, 1 is a multi-stage dry pump (dry pump), 2, 2 ′ is a pump housing, 5, 6, 7 are partition walls, 8, 9, 10, 11 are pump chambers, 12, 13, 14, 15, 12 ′. , 13 ', 14', 15 'are rotors, 16, 16' are rotating shafts, 23 are side housings, 25, 25 'are bearings, 26 is an intermediate chamber, 29 is a cooling housing, 30 is a cooling passage, 31 is lubrication An oil housing, 32 is lubricating oil, 33 is a lubricating oil chamber (lubricating oil reservoir), and 34 and 34 'are rotor rotating members.

Claims (10)

A housing body having a pump chamber and an intake port and an exhaust port communicating with the pump chamber;
A rotary shaft installed on the housing body and a rotor located in the pump chamber and disposed integrally with the rotary shaft, and compressing the gas sucked from the intake port as it rotates, from the exhaust port A rotor rotating member to be exhausted;
In a dry pump comprising a lubricating oil reservoir disposed in the housing body and storing lubricating oil,
The housing body is
A heat insulating intermediate chamber formed between the pump chamber and the lubricating oil reservoir, and a cooling passage that is formed between the pump chamber and the lubricating oil reservoir and allows the refrigerant to pass therethrough. A dry pump comprising: 2. The dry pump according to claim 1, wherein the intermediate chamber and the cooling passage are formed in this order from the pump chamber toward the lubricating oil reservoir. 3. The housing main body according to claim 1, wherein the housing main body includes a pump housing having the pump chamber, a side housing attached to at least one end of both ends of the pump housing, and the pump housing of the side housing. And a cooling housing attached to the opposite side, and
The intermediate pump is formed in the side housing, and the cooling passage is formed in the cooling housing. A housing body having a pump chamber and an intake port and an exhaust port communicating with the pump chamber;
A rotary shaft installed on the housing body and a rotor located in the pump chamber and disposed integrally with the rotary shaft, and compressing the gas sucked from the intake port as it rotates, from the exhaust port A rotor rotating member to be exhausted;
In a dry pump comprising a lubricating oil reservoir disposed in the housing body and storing lubricating oil,
The housing body includes a pump housing having the pump chamber, a side housing attached to at least one end of both ends of the pump housing, and a cooling housing attached to the side of the side housing opposite to the pump housing. And, and
The cooling housing has a cooling passage for allowing a refrigerant to pass between the pump chamber and the lubricating oil reservoir, and the side housing is made of a material having a lower heat transfer coefficient than the cooling housing. A dry pump characterized in that the cooling housing is made of a material having a higher heat transfer coefficient than the side housing. 5. The dry pump according to claim 4, wherein the side housing is formed using an iron-nickel alloy as a base material. A housing body having a pump chamber and an intake port and an exhaust port communicating with the pump chamber;
A rotary shaft installed in the housing main body and a rotor located in the pump chamber and integrally disposed on the rotary shaft, and exhausted from the exhaust port while compressing the gas sucked from the intake port as it rotates. A rotor rotating member that
In a dry pump comprising a lubricating oil reservoir disposed in the housing body and storing lubricating oil,
The housing body includes a pump housing having the pump chamber, and a side housing attached to at least one end of both ends of the pump housing, and
The side housing is formed between the pump chamber and the lubricating oil reservoir and is formed between the pump chamber and the lubricating oil reservoir, and is formed between the pump chamber and the lubricating oil reservoir. A dry pump having a cooling passage. 7. The side housing according to claim 6, wherein the side housing is made of a material having a heat transfer coefficient lower than that of the cooling housing, and the cooling housing is made of a material having a heat transfer coefficient higher than that of the side housing. And dry pump. In one of claims 3, 4, 5, 6, and 7, at least one of the pump housing and the side housing is based on a material having a heat transfer coefficient of 15 W / m · K or less, A dry pump characterized by reduced heat transfer. In any one of Claims 1-8, at least one of the said rotating shaft, the said pump housing, and the said side housing has a linear expansion coefficient of 6 * 10 < ^-6 > m / m * K or less. A dry pump characterized in that it is formed using a material as a base material, and thermal expansion is suppressed. 10. The pump chamber according to claim 1, wherein a plurality of the pump chambers are arranged in parallel along the axial length direction of the rotating shaft, and the rotor of the rotor rotating member is the rotating shaft. A plurality of the pumps are arranged in parallel along the axial length direction, and are arranged rotatably in each of the pump chambers.

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