JP5677202B2 - Vacuum pump - Google Patents

Vacuum pump Download PDF

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JP5677202B2
JP5677202B2 JP2011123980A JP2011123980A JP5677202B2 JP 5677202 B2 JP5677202 B2 JP 5677202B2 JP 2011123980 A JP2011123980 A JP 2011123980A JP 2011123980 A JP2011123980 A JP 2011123980A JP 5677202 B2 JP5677202 B2 JP 5677202B2
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chamber
pump
pump chamber
wall
stage
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JP2012251471A (en
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壮一 百済
壮一 百済
恵弘 新村
恵弘 新村
真己 長山
真己 長山
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Ebara Corp
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Ebara Corp
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Priority to JP2011123980A priority Critical patent/JP5677202B2/en
Priority to TW101118674A priority patent/TWI554684B/en
Priority to EP12793624.3A priority patent/EP2715139B1/en
Priority to KR1020137028886A priority patent/KR101760550B1/en
Priority to PCT/JP2012/064346 priority patent/WO2012165645A1/en
Priority to CN2012800187110A priority patent/CN103477080A/en
Priority to US14/119,858 priority patent/US20140112815A1/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C13/00—Adaptations of machines or pumps for special use, e.g. for extremely high pressures
    • F04C13/007—Venting; Gas and vapour separation during pumping
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C18/12—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
    • F04C18/126—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with radially from the rotor body extending elements, not necessarily co-operating with corresponding recesses in the other rotor, e.g. lobes, Roots type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C18/12—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
    • F04C18/14—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
    • F04C18/18—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with similar tooth forms
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C23/00—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C23/00—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids
    • F04C23/001—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids of similar working principle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C25/00—Adaptations of pumps for special use of pumps for elastic fluids
    • F04C25/02—Adaptations of pumps for special use of pumps for elastic fluids for producing high vacuum
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C27/00—Sealing arrangements in rotary-piston pumps specially adapted for elastic fluids
    • F04C27/008—Sealing arrangements in rotary-piston pumps specially adapted for elastic fluids for other than working fluid, i.e. the sealing arrangements are not between working chambers of the machine
    • F04C27/009—Shaft sealings specially adapted for pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2220/00—Application
    • F04C2220/10—Vacuum
    • F04C2220/12—Dry running
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2220/00—Application
    • F04C2220/30—Use in a chemical vapor deposition [CVD] process or in a similar process
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2220/00—Application
    • F04C2220/40—Pumps with means for venting areas other than the working chamber, e.g. bearings, gear chambers, shaft seals
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2240/00—Components
    • F04C2240/30—Casings or housings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2280/00—Arrangements for preventing or removing deposits or corrosion
    • F04C2280/02—Preventing solid deposits in pumps, e.g. in vacuum pumps with chemical vapour deposition [CVD] processes

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)

Description

本発明は、半導体、液晶、太陽電池、ＬＥＤ等の製造工程の一つであるＣＶＤやエッチングといったプロセスで使用される真空ポンプであって、ポンプ内部に昇華性ガスや腐食性ガスが流入するプロセスで使用される真空ポンプに関する。   The present invention is a vacuum pump used in a process such as CVD or etching, which is one of the manufacturing processes of semiconductors, liquid crystals, solar cells, LEDs, etc., and a process in which sublimation gas or corrosive gas flows into the pump. Relates to a vacuum pump used in the above.

例えば、真空チャンバに接続されて、真空チャンバ内に導入したプロセスガスを排気するのに使用される真空ポンプは、一般に、吸気口と排気口とを有し、内部にポンプ室を備えたポンプケーシングと、このポンプケーシングの内部に収容されたロータとを有し、ポンプ室の内部でロータを回転させることで、プロセスガスを吸気口からポンプケーシング内部に流入させて圧縮し、排気口から外部に排気するように構成されている。ロータは、ポンプケーシングの内部を延びる回転軸に固定され、回転軸の両端は、ポンプケーシングの側方に配置された室の内部に収容された一対の軸受で回転自在に支承されている。   For example, a vacuum pump connected to a vacuum chamber and used for exhausting process gas introduced into the vacuum chamber is generally a pump casing having an intake port and an exhaust port and having a pump chamber therein. And a rotor housed inside the pump casing, and by rotating the rotor inside the pump chamber, the process gas flows into the pump casing from the intake port and is compressed, and the exhaust port exits to the outside. It is configured to exhaust. The rotor is fixed to a rotating shaft extending inside the pump casing, and both ends of the rotating shaft are rotatably supported by a pair of bearings housed in a chamber disposed on the side of the pump casing.

このため、真空ポンプの真空チャンバに接続されるポンプケーシングの吸気口付近は、真空チャンバの内部と同じ真空状態となり、ポンプケーシングの排気口付近は、大気に開放されてほぼ大気圧となる。回転軸は、その両端を軸受によって回転自在に支承されているとともに、軸受に入ったプロセスガスによって生成された生成物で軸受が破壊されるのを防止するため、接触シールまたは非接触シールでシールされている。回転軸のシールには、接触による損傷を防止した非接触シールが広く使用されている。   For this reason, the vicinity of the intake port of the pump casing connected to the vacuum chamber of the vacuum pump is in the same vacuum state as the inside of the vacuum chamber, and the vicinity of the exhaust port of the pump casing is opened to the atmosphere and becomes almost atmospheric pressure. The rotating shaft is rotatably supported by bearings at both ends, and is sealed with a contact seal or non-contact seal to prevent the bearing from being destroyed by the product generated by the process gas entering the bearing. Has been. Non-contact seals that prevent damage due to contact are widely used as seals for rotary shafts.

例えば、複数段のポンプ室を有する多段真空ポンプを使用して真空チャンバ等の内部を真空排気する場合は、１段目よりも２段目、２段目よりも３段目と、段数が増加するに従ってポンプ室の内部圧力が段階的に増加し、しかも、同じポンプ室であっても、ポンプ室の出口側に位置する気体の方が入口側に位置する気体よりも圧力が高くなる。つまり、最終段ポンプ室の出口側（排気口）がほぼ大気圧となり、最終段ポンプ室の入口側は大気圧よりも低い圧力となる。摩耗を防止するため、回転軸のシールに非接触シールを使用した場合、最終段ポンプ室に隣接して内部に軸受を収納した室の内部圧力は、最終段ポンプ室の内部圧力（平均圧力）に見合った圧力となる。例えば、真空ポンプの最終段ポンプ室の出口側（排気口）がほぼ大気圧の７６０Ｔｏｒｒで、最終段ポンプ室の入口側が大気圧よりも低い２００Ｔｏｒｒである場合、最終段ポンプ室に隣接して内部に軸受を収納した室の内部圧力は、およそ４８０Ｔｏｒｒ（＝（７６０＋２００）／２）となる。   For example, when the inside of a vacuum chamber or the like is evacuated using a multi-stage vacuum pump having a multi-stage pump chamber, the number of stages increases to the second stage from the first stage and the third stage from the second stage. Accordingly, the internal pressure of the pump chamber gradually increases, and even in the same pump chamber, the gas located on the outlet side of the pump chamber has a higher pressure than the gas located on the inlet side. That is, the outlet side (exhaust port) of the final stage pump chamber is almost at atmospheric pressure, and the inlet side of the final stage pump chamber is at a pressure lower than atmospheric pressure. In order to prevent wear, when a non-contact seal is used for the rotary shaft, the internal pressure of the chamber containing the bearing adjacent to the final stage pump chamber is the internal pressure (average pressure) of the final stage pump chamber. The pressure is commensurate with For example, when the outlet side (exhaust port) of the final stage pump chamber of the vacuum pump is 760 Torr, which is substantially atmospheric pressure, and the inlet side of the final stage pump chamber is 200 Torr, which is lower than the atmospheric pressure, the interior is adjacent to the final stage pump chamber. The internal pressure of the chamber containing the bearing is about 480 Torr (= (760 + 200) / 2).

最終段ポンプ室の入口側の圧力は、真空チャンバ側からのプロセスガスの流入等によって変化する。例えば、真空チャンバ側からプロセスガスが流入すると、最終段ポンプ室の入口側の圧力が２００Ｔｏｒｒから３００Ｔｏｒｒに上昇する。一方、最終段ポンプ室の出口側圧力は、ポンプ排気管を通し大気に連通しているため、大気圧からほとんど変化しない。そして、最終段ポンプ室の入口側の圧力が２００Ｔｏｒｒから３００Ｔｏｒｒに変化すると、最終段ポンプ室内の内部圧力（平均圧力）は、５３０Ｔｏｒｒ（＝（７６０＋３００）／２）となり、最終段ポンプ室に隣接して内部に軸受を収納した室の内部圧力の４８０Ｔｏｒｒよりも高くなる。   The pressure on the inlet side of the final stage pump chamber changes due to the inflow of process gas from the vacuum chamber side. For example, when process gas flows from the vacuum chamber side, the pressure on the inlet side of the final stage pump chamber increases from 200 Torr to 300 Torr. On the other hand, the outlet side pressure of the final stage pump chamber hardly changes from the atmospheric pressure because it communicates with the atmosphere through the pump exhaust pipe. When the pressure on the inlet side of the final stage pump chamber changes from 200 Torr to 300 Torr, the internal pressure (average pressure) in the final stage pump chamber becomes 530 Torr (= (760 + 300) / 2), which is adjacent to the final stage pump chamber. Thus, the internal pressure of the chamber containing the bearing is higher than 480 Torr.

そして、このように最終段ポンプ室内の平均圧力の方が最終段ポンプ室に隣接して内部に軸受を収納した室の内部圧力よりも高くなると、この室の内部に最終段ポンプ室の内部に流入したプロセスガスが漏れる。このように、軸受を収納した室の内部にプロセスガスが漏れると、プロセスガスに昇華性物質等が含まれている場合、該室の温度は一般に低いため、該室の内部に配置されている軸受や軸受を潤滑するための潤滑油に生成物等の析出物が析出して、軸受損傷の原因となる。   When the average pressure in the final stage pump chamber becomes higher than the internal pressure of the chamber in which the bearing is housed adjacent to the final stage pump chamber in this way, the inside of the final stage pump chamber is placed inside this chamber. Inflowing process gas leaks. As described above, when the process gas leaks into the chamber containing the bearing, when the process gas contains a sublimable substance or the like, the temperature of the chamber is generally low, and thus the chamber is arranged inside the chamber. Precipitates such as products are deposited in the lubricating oil for lubricating the bearing and the bearing, which causes damage to the bearing.

なお、凝縮性気体や昇華性気体等の気体の排気に適するようにポンプ室の温度を高めに維持しつつ、潤滑油室の潤滑油の温度を低めに維持するのに有利で、潤滑油の蒸気化を抑えるため、相対的に温度が高めのポンプ室と相対的に温度が低めの潤滑油室との間に中空状をなす断熱用の中間室と、冷媒を通過させる冷却通路とを形成するようにしたドライポンプが提案されている（特許文献１参照）。   It is advantageous to keep the temperature of the lubricating oil in the lubricating oil chamber low while keeping the temperature of the pump chamber high so that it is suitable for exhausting gases such as condensable gas and sublimable gas. In order to suppress vaporization, a heat-insulating intermediate chamber and a cooling passage through which the refrigerant passes are formed between a pump chamber having a relatively high temperature and a lubricating oil chamber having a relatively low temperature. A dry pump designed to do this has been proposed (see Patent Document 1).

特開２００５−１０５８２９号公報JP 2005-105829 A

しかしながら、特許文献１に記載のドライポンプは、凝縮性気体や昇華性気体等の気体の排気に適するようにポンプ室の温度を高めに維持しつつ、潤滑油室の潤滑油の温度を低めに維持するのに有利で、潤滑油の蒸気化を抑えるようにしたものであって、ポンプケーシングの側方に位置する室の内部に収容された軸受をプロセスガスから保護するようにしたものではない。なお、回転軸の非接触シールにＮ２ガス等のパージガスを導入することで、プロセスガスの軸受側への漏れを防止することも広く行われているが、回転軸の非接触シールに導入するＮ２ガス等のパージガスの量を増やすとポンプ室の圧力も悪くなってしまうため、回転軸の非接触シールに導入するＮ２ガス等のパージガスの量には一定の限界がある。 However, the dry pump described in Patent Document 1 keeps the temperature of the lubricating oil in the lubricating oil chamber low while maintaining the pump chamber at a high temperature so as to be suitable for exhausting gases such as condensable gas and sublimable gas. It is advantageous to maintain and suppresses the vaporization of the lubricating oil, and does not protect the bearing housed inside the chamber located on the side of the pump casing from the process gas. . In addition, by introducing a purge gas such as N 2 gas into the non-contact seal of the rotating shaft, it is widely practiced to prevent the process gas from leaking to the bearing side, but it is introduced into the non-contact seal of the rotating shaft. If the amount of purge gas such as N 2 gas is increased, the pressure in the pump chamber also deteriorates, and therefore the amount of purge gas such as N 2 gas introduced into the non-contact seal of the rotating shaft has a certain limit.

本発明は上記事情に鑑みて為されたもので、ポンプ内部に流入したプロセスガスが軸受側に漏れることをより確実に防止して、軸受をプロセスガスから保護できるようにした真空ポンプを提供することを目的とする。   The present invention has been made in view of the above circumstances, and provides a vacuum pump that can more reliably prevent the process gas flowing into the pump from leaking to the bearing side and protect the bearing from the process gas. For the purpose.

請求項１に記載の発明は、吸気口と排気口とを有し、互いに連通し、仕切壁で仕切られた複数段のポンプ室を内部に備えたポンプケーシングと、両端を軸受で回転自在に支承されて前記ポンプケーシングの長さ方向に沿って配置される回転軸と、前記ポンプ室内にそれぞれ収容され、前記回転軸に連結されて該回転軸の回転に伴って回転する複数のロータとを有し、最終段ポンプ室は、吸気側の仕切壁と排気側の端壁によって形成され、前記排気側の端壁の側方にはサイドパネルが設けられており、前記端壁と前記サイドパネルの間には、前記排気口に連通し大気に開放させた大気開放室が設けられており、前記ポンプケーシングは、内壁と該内壁と所定間隔離間して配置される外壁とを備えた二重壁構造を有していることを特徴とする真空ポンプである。 According to the first aspect of the present invention, there is provided a pump casing having an intake port and an exhaust port , communicated with each other, and provided with a plurality of stages of pump chambers partitioned by a partition wall; A rotating shaft that is supported and disposed along the length direction of the pump casing, and a plurality of rotors that are respectively housed in the pump chamber and that are coupled to the rotating shaft and rotate as the rotating shaft rotates. The final-stage pump chamber is formed by a partition wall on the intake side and an end wall on the exhaust side, and a side panel is provided on a side of the end wall on the exhaust side, and the end wall and the side panel between the and air release chamber is opened to the atmosphere communication is provided in the exhaust port, the pump casing, the two having an outer wall which is spaced apart inner walls and inner walls and the predetermined distance double vacuum, characterized in that it has a wall structure It is a pump.

このように、ポンプケーシングの排気口側に該排気口に連通し大気に開放させた大気開放室を設けることで、たとえポンプ室の内部圧力が変化し、回転軸のシールに非接触シールを使用した場合でも、大気開放室の側方に位置して内部に軸受を収容している室の内部が常にほぼ大気圧となるようにすることができる。これによって、ポンプ室内に流入したプロセスガスが大気開放室の側方に位置して内部に軸受を収容している室の内部に漏れてしまうことをより確実に防止して、軸受をプロセスガスから保護することができる。   In this way, by providing an air release chamber on the exhaust port side of the pump casing that is connected to the exhaust port and opened to the atmosphere, the internal pressure of the pump chamber changes, and a non-contact seal is used for the seal of the rotating shaft. Even in this case, the interior of the chamber that is located on the side of the open air chamber and that houses the bearing therein can always be at almost atmospheric pressure. This more reliably prevents the process gas flowing into the pump chamber from leaking into the chamber that is located on the side of the open air chamber and accommodates the bearing therein, and removes the bearing from the process gas. Can be protected.

多段真空ポンプにあっては、前述のように、最終段ポンプ室の出口側（排気口）がほぼ大気圧となっても、最終段ポンプ室の入口側は大気圧よりも低い圧力となり、真空チャンバ側からプロセスガスが流入すると、最終段ポンプ室の内部圧力（平均圧力）が変化（上昇）するが、最終段ポンプ室の側方に大気開放室を設けることで、最終段ポンプ室の内部圧力（平均圧力）が変化（上昇）しても、この圧力変化が大気開放室の側方に位置して内部に軸受を収容している室内の圧力に影響することを防止することができる。   In the multi-stage vacuum pump, as described above, even if the outlet side (exhaust port) of the final stage pump chamber is almost atmospheric pressure, the inlet side of the final stage pump chamber has a pressure lower than the atmospheric pressure, and vacuum When the process gas flows in from the chamber side, the internal pressure (average pressure) of the final stage pump chamber changes (increases). By providing an air release chamber on the side of the final stage pump chamber, the internal pressure of the final stage pump chamber Even if the pressure (average pressure) changes (increases), this pressure change can be prevented from affecting the pressure in the chamber that is located on the side of the open air chamber and that houses the bearing therein.

請求項２に記載の発明は、前記サイドパネルの内部には前記回転軸が挿通されており、該回転軸の挿通部にパージガスを供給するパージガス通路が設けられていることを特徴とする請求項１記載の真空ポンプである。
請求項３に記載の発明は、前記大気開放室は一定の幅を有していることを特徴とする請求項１または２に記載の真空ポンプである。 Invention according to claim 2, the inside of the side panels, wherein the and rotary shaft is inserted, the purge gas passage for supplying purge gas into the insertion portion of the rotary shaft is provided according claim 1 Symbol placing vacuum pump.
A third aspect of the present invention is the vacuum pump according to the first or second aspect, wherein the atmosphere release chamber has a certain width.

このように、内部に回転軸を挿通させるサイドパネルに、該回転軸の挿通部にパージガスを供給するパージガス通路を設けることで、サイドパネルと回転軸との間に、接触による摩耗を防止した非接触シールを構成することができる。   Thus, by providing a purge gas passage for supplying purge gas to the insertion portion of the rotary shaft in the side panel through which the rotary shaft is inserted, wear due to contact between the side panel and the rotary shaft is prevented. A contact seal can be constructed.

本発明によれば、たとえポンプ室の内部圧力が変化しても、大気開放室の側方に位置して内部に軸受を収容している室の内部圧力が常に大気圧となるため、ポンプ室内に流入したプロセスガスが大気開放室の側方に位置して内部に軸受を収容している室内に漏れてしまうことをより確実に防止して、軸受をプロセスガスから保護することができる。   According to the present invention, even if the internal pressure of the pump chamber changes, the internal pressure of the chamber located on the side of the atmosphere release chamber and containing the bearing therein is always atmospheric pressure. It is possible to more reliably prevent the process gas that has flowed into the chamber from leaking into the chamber that is located on the side of the open air chamber and accommodates the bearing therein, thereby protecting the bearing from the process gas.

本発明の実施形態の真空ポンプを示す縦断正面図である。It is a vertical front view which shows the vacuum pump of embodiment of this invention. 図１に示す真空ポンプに備えられているメインポンプの第１段ポンプ室の縦断側面図である。It is a vertical side view of the 1st stage | paragraph pump chamber of the main pump with which the vacuum pump shown in FIG. 1 is equipped.

以下、本発明の実施形態を図面に基づいて説明する。図１は、本発明の実施形態に係る真空ポンプ１０の縦断正面図を示す。図１に示すように、真空ポンプ１０は、真空側に配置されるブースタポンプ１２と大気側に配置されるメインポンプ１４とを有しており、ブースタポンプ１２とメインポンプ１４は、連絡配管１６で互いに接続されている。この例にあっては、メインポンプ１４として、６段のルーツ式真空ポンプが使用され、単段のルーツ式真空ポンプからなるブースタポンプ１２と組合せて使用するように構成されている。   Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a longitudinal front view of 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 atmosphere side. The booster pump 12 and the main pump 14 are connected to a communication pipe 16. Are connected to each other. In this example, a six-stage Roots type vacuum pump is used as the main pump 14 and is configured to be used in combination with a booster pump 12 composed of a single-stage Roots type vacuum pump.

ブースタポンプ１２は、内部にポンプ室１８を区画形成する略円筒状の外胴２０を有するポンプケーシング２２と、モータ２４の駆動に伴って互いに同期して逆方向に回転する一対の回転軸２６とを有している。ポンプ室１８内には、互いに隣接する位置に、所定のクリアランスをもって、例えば２葉のロータからなる一対のロータ２８がそれぞれ回転自在に収容され、この各ロータ２８は、回転軸２６にそれぞれ固着されている。ポンプケーシング２２の外胴２０には、処理対象の真空チャンバ等から延びる吐出管（図示せず）に接続される吸気口２０ａと、連絡配管１６に接続される排気口２０ｂが設けられている。これによって、一対のロータ２８の互いに同期した逆方向の回転に伴って、吸気口２０ａからポンプ室１８内にプロセスガスを流入させ、圧縮させて排気口２０ｂから外部に移送するようになっている。なお、図１には、回転軸２６及び該回転軸２６の駆動機構等の一方のみが図示されているが、紙面と反対側にもほぼ同様な構成が備えられている。   The booster pump 12 includes a pump casing 22 having a substantially cylindrical outer body 20 that defines a pump chamber 18 therein, and a pair of rotating shafts 26 that rotate in opposite directions in synchronization with the driving of the motor 24. have. In the pump chamber 18, a pair of rotors 28 made of, for example, two-leaf rotors are rotatably accommodated at positions adjacent to each other with a predetermined clearance, and each rotor 28 is fixed to the rotating shaft 26. ing. The outer body 20 of the pump casing 22 is provided with an intake port 20 a connected to a discharge pipe (not shown) extending from a vacuum chamber to be processed and an exhaust port 20 b connected to the communication pipe 16. As a result, the process gas flows into the pump chamber 18 from the intake port 20a and is compressed and transferred to the outside through the exhaust port 20b as the pair of rotors 28 rotate in opposite directions in synchronization with each other. . In FIG. 1, only one of the rotating shaft 26 and the driving mechanism of the rotating shaft 26 is shown, but a substantially similar configuration is provided on the side opposite to the paper surface.

この例において、ポンプケーシング２２の外胴２０の吸気口２０ａ及び排気口２０ｂを除く領域の外周部は、略円筒状のヒータジャケット３０で一体的に包囲されている。これによって、ポンプ室１８の内部がヒータジャケット３０で加熱されるようになっている。   In this example, the outer peripheral portion of the outer casing 20 of the pump casing 22 excluding the intake port 20 a and the exhaust port 20 b is integrally surrounded by a substantially cylindrical heater jacket 30. As a result, the inside of the pump chamber 18 is heated by the heater jacket 30.

ブースタポンプ１２は、一般に真空度が高い（圧力が低い）ため、圧縮熱があまり発生せず、ポンプ温度が低くなっている。このため、たとえポンプ室１８内の圧力が低くても、ポンプ室１８内に流入したプロセスガスに含まれる昇華性物質等がポンプ室１８の内周面等に析出する恐れがあるが、前述のように、ヒータジャケット３０で、ポンプ室１８内の温度を上昇させることで、ポンプ室１８内に流入したプロセスガスに含まれる昇華性物質等がポンプ室１８の内周面等に析出することを防止することができる。   Since the booster pump 12 generally has a high degree of vacuum (pressure is low), compression heat is not generated so much and the pump temperature is low. For this reason, even if the pressure in the pump chamber 18 is low, a sublimable substance or the like contained in the process gas flowing into the pump chamber 18 may be deposited on the inner peripheral surface of the pump chamber 18. As described above, by raising the temperature in the pump chamber 18 with the heater jacket 30, the sublimable substance contained in the process gas flowing into the pump chamber 18 is deposited on the inner peripheral surface of the pump chamber 18. Can be prevented.

ポンプケーシング２２の両側方には、サイドパネル３２ａ，３２ｂがそれぞれ配置され、この各サイドパネル３２ａ，３２ｂにそれぞれ取り付けた軸受ハウジング３４ａ，３４ｂ内に収容した軸受３６ａ，３６ｂを介して、回転軸２６がその両端において回転自在に支承されている。更に、サイドパネル３２ａ，３２ｂの側方に位置して、内部に潤滑油を溜める潤滑油ハウジング４０ａ，４０ｂが配置され、一方の潤滑油ハウジング４０ｂにモータ２４のモータハウジングが連結されている。   Side panels 32a and 32b are respectively arranged on both sides of the pump casing 22, and the rotary shaft 26 is provided via bearings 36a and 36b accommodated in bearing housings 34a and 34b attached to the side panels 32a and 32b, respectively. Is rotatably supported at both ends thereof. Further, lubricating oil housings 40a and 40b for storing lubricating oil are disposed inside the side panels 32a and 32b, and the motor housing of the motor 24 is connected to one lubricating oil housing 40b.

サイドパネル３２ａ，３２ｂには、サイドパネル３２ａ，３２ｂの回転軸２６の挿通部にＮ２ガス等のパージガスを供給して、ポンプ室１８内に流入したプロセスガスが軸受３６ａ，３６ｂの方向に流出することを防止するためのパージガス通路４２ａ，４２ｂがそれぞれ設けられ、これによって、サイドパネル３２ａ，３２ｂと回転軸２６との間に、接触による摩耗を防止した非接触シールが構成されている。 A purge gas such as N 2 gas is supplied to the side panels 32a and 32b through the insertion portion of the rotating shaft 26 of the side panels 32a and 32b, and the process gas flowing into the pump chamber 18 flows out in the direction of the bearings 36a and 36b. Purge gas passages 42a and 42b for preventing this are provided, and thereby a non-contact seal is formed between the side panels 32a and 32b and the rotary shaft 26 to prevent wear due to contact.

メインポンプ１４は、この例では、６段のルーツ式真空ポンプで構成されており、内部に第１〜第６の合計６段のポンプ室５０ａ〜５０ｆと、第６段ポンプ室５０ｆに隣接する大気開放室５２を区画形成する略円筒状の外胴５４を有するポンプケーシング５６と、モータ５８の駆動に伴って互いに同期して逆方向に回転する一対の回転軸６０を有している。第１段ポンプ室５０ａの内部には、図２に示すように、例えば３葉ロータからなる一対のロータ６２ａがそれぞれ回転自在に収容されている。同様に、第２段ポンプ室５０ｂの内部には、例えば３葉ロータからなる一対のロータ６２ｂが、第３段ポンプ室５０ｃの内部には、例えば３葉ロータからなる一対のロータ６２ｃが、第４段ポンプ室５０ｄの内部には、例えば３葉ロータからなる一対のロータ６２ｄが、第５段ポンプ室５０ｅの内部には、例えば３葉ロータからなる一対のロータ６２ｅが、第６段ポンプ室５０ｆの内部には、例えば３葉ロータからなる一対のロータ６２ｆがそれぞれ収容されている。そして、直線状に並ぶ一方のロータ６２ａ〜６２ｆは一方の回転軸６０に、他方のロータ６２ａ〜６２ｆは他方の回転軸６０にそれぞれ固着されている。   In this example, the main pump 14 is composed of a six-stage roots-type vacuum pump, and is adjacent to the first to sixth total six-stage pump chambers 50a to 50f and the sixth-stage pump chamber 50f. A pump casing 56 having a substantially cylindrical outer body 54 that defines the atmosphere opening chamber 52 and a pair of rotating shafts 60 that rotate in opposite directions in synchronization with driving of the motor 58 are provided. As shown in FIG. 2, a pair of rotors 62a made of, for example, a three-leaf rotor is housed in the first stage pump chamber 50a so as to be rotatable. Similarly, a pair of rotors 62b made of, for example, a three-leaf rotor is provided inside the second stage pump chamber 50b, and a pair of rotors 62c made of, for example, a three-leaf rotor is placed inside the third stage pump chamber 50c. A pair of rotors 62d made of, for example, a three-leaf rotor is disposed inside the four-stage pump chamber 50d, and a pair of rotors 62e composed of, for example, a three-leaf rotor is disposed inside the fifth-stage pump chamber 50e. A pair of rotors 62f made of, for example, a three-leaf rotor are accommodated inside 50f. One rotor 62 a to 62 f arranged in a straight line is fixed to one rotating shaft 60, and the other rotor 62 a to 62 f is fixed to the other rotating shaft 60.

ポンプケーシング５６は、外胴５４の端部を閉塞する一対の端壁６４ａ，６４ｂと、外胴５４の内部を仕切る５枚の仕切壁６６ａ〜６６ｅとを有しており、一方の端壁６４ａと第１仕切壁６６ａとの間に第１段ポンプ室５０ａが、第１仕切壁６６ａと第２仕切壁６６ｂとの間に第２段ポンプ室５０ｂが、第２仕切壁６６ｂと第３仕切壁６６ｃとの間に第３段ポンプ室５０ｃが、第３仕切壁６６ｃと第４仕切壁６６ｄとの間に第４段ポンプ室５０ｄが、第４仕切壁６６ｄと第５仕切壁６６ｅとの間に第５段ポンプ室５０ｅが、第５仕切壁６６ｅと他方の端壁６４ｂとの間に第６段ポンプ室５０ｆがそれぞれ形成されている。そして、他方の端壁６４ｂと該端壁６４ｂに隣接するサイドパネル８０ｂの間に大気開放室５２が形成されている。   The pump casing 56 includes a pair of end walls 64a and 64b that closes the end of the outer cylinder 54, and five partition walls 66a to 66e that partition the inside of the outer cylinder 54, and one end wall 64a. Between the first partition wall 66a and the first partition wall 66a, the second stage pump chamber 50b between the first partition wall 66a and the second partition wall 66b, the second partition wall 66b and the third partition. The third-stage pump chamber 50c is between the wall 66c, the fourth-stage pump chamber 50d is between the third partition wall 66c and the fourth partition wall 66d, and the fourth partition wall 66d and the fifth partition wall 66e. A fifth-stage pump chamber 50e is formed therebetween, and a sixth-stage pump chamber 50f is formed between the fifth partition wall 66e and the other end wall 64b. An air release chamber 52 is formed between the other end wall 64b and the side panel 80b adjacent to the end wall 64b.

第１段ポンプ室５０ａは、図２に示すように、一対のロータ６２ａの互いに同期した逆方向の回転に伴って、この入口側（図示では上側、以下同じ）から第１段ポンプ室５０ａの内部にプロセスガスを流入させて圧縮し、出口側（図示では下側、以下同じ）から第１段ポンプ室５０ａの外部にプロセスガスを移送するようになっている。このことは、第２段〜第６段ポンプ室５０ｂ〜５０ｆにあってもほぼ同様である。   As shown in FIG. 2, the first-stage pump chamber 50 a moves from the inlet side (the upper side in the drawing, the same applies hereinafter) to the first-stage pump chamber 50 a as the pair of rotors 62 a rotate in opposite directions. The process gas is introduced into the interior and compressed, and the process gas is transferred from the outlet side (lower side in the drawing, the same applies hereinafter) to the outside of the first stage pump chamber 50a. This is substantially the same even in the second to sixth stage pump chambers 50b to 50f.

ポンプケーシング５６の外胴５４には、連絡配管１６に接続されて第１段ポンプ室５０ａの入口側（上側）に連通する吸気口５４ａと、第６段ポンプ室（最終段ポンプ室）５０ｆの出口側（下側）に連通する排気口５４ｂが設けられている。また排気口５４ｂは、端壁６４ｂを介して大気開放室５２に連通している。これにより、大気開放室５２は、排気口５４ｂを通して大気に開放される。更に、ポンプケーシング５６の外胴５４は、内壁６８と該内壁６８と所定間隔離間して配置される外壁７０とを備えた二重壁構造を有しており、内壁６８と外壁７０との間にガス通路７２ａ〜７２ｅが形成されている。つまり、第１段ポンプ室５０ａの周囲に第１ガス通路７２ａが、第２段ポンプ室５０ｂの周囲に第２ガス通路７２ｂが、第３段ポンプ室５０ｃの周囲に第３ガス通路７２ｃが、第４段ポンプ室５０ｄの周囲に第４ガス通路７２ｄが、第５段ポンプ室５０ｅの周囲に第５ガス通路７２ｅがそれぞれ形成されている。第５段ガス通路７２ｅは、さらに、第６段ポンプ室５０ｆの周囲に拡張している。   The outer body 54 of the pump casing 56 is connected to the communication pipe 16 and communicates with the inlet side (upper side) of the first stage pump chamber 50a, and the sixth stage pump chamber (final stage pump chamber) 50f. An exhaust port 54b communicating with the outlet side (lower side) is provided. Further, the exhaust port 54b communicates with the atmosphere opening chamber 52 through the end wall 64b. Thereby, the atmosphere release chamber 52 is opened to the atmosphere through the exhaust port 54b. Further, the outer cylinder 54 of the pump casing 56 has a double wall structure including an inner wall 68 and an outer wall 70 that is spaced apart from the inner wall 68 by a predetermined distance, and between the inner wall 68 and the outer wall 70. Gas passages 72a to 72e are formed in the upper part. That is, the first gas passage 72a around the first stage pump chamber 50a, the second gas passage 72b around the second stage pump chamber 50b, and the third gas passage 72c around the third stage pump chamber 50c, A fourth gas passage 72d is formed around the fourth stage pump chamber 50d, and a fifth gas passage 72e is formed around the fifth stage pump chamber 50e. The fifth stage gas passage 72e further extends around the sixth stage pump chamber 50f.

これらの各ガス通路７２ａ〜７２ｅの一方は、各ポンプ室５０ａ〜５０ｅの出口側（下側）で各ポンプ室５０ａ〜５０ｅの内部にそれぞれ連通し、各ガス通路７２ａ〜７２ｅの他方は、各ポンプ室５０ｂ〜５０ｆの入口側（上側）で各ポンプ室５０ｂ〜５０ｆの内部にそれぞれ連通している。これによって、図２に示すように、吸気口５４ａを通して入口側から第１段ポンプ室５０ａ内に流入したプロセスガスは、第１段ポンプ室５０ａの内部を通過した後、第１段ポンプ室５０ａの出口側（下側）から第１ガス通路７２ａ内に流入し、該第１ガス通路７２ａに沿って上方に流れた後、第２段ポンプ室５０ｂの入口側（上側）に達する。そして、入口側から第２段ポンプ室５０ｂ内に流入したプロセスガスは、第２段ポンプ室５０ｂの内部を通過した後、第２段ポンプ室５０ｂの出口側から第２ガス通路７２ｂ内に流入し、該第２ガス通路７２ｂに沿って上方に流れた後、第３段ポンプ室５０ｃの入口側に達する。このようにして、プロセスガスは、更に第３段〜第６段ポンプ室５０ｃ〜５０ｆ内を順次通過した後、第６段ポンプ室５０ｆの出口側から排気口５４ｂを通して外部に排気される。   One of these gas passages 72a to 72e communicates with the inside of each pump chamber 50a to 50e on the outlet side (lower side) of each pump chamber 50a to 50e, and the other of each gas passage 72a to 72e The pump chambers 50b to 50f communicate with the interiors of the pump chambers 50b to 50f on the inlet side (upper side). Accordingly, as shown in FIG. 2, the process gas that has flowed into the first stage pump chamber 50a from the inlet side through the intake port 54a passes through the inside of the first stage pump chamber 50a, and then the first stage pump chamber 50a. The gas flows into the first gas passage 72a from the outlet side (lower side) of the gas, flows upward along the first gas passage 72a, and then reaches the inlet side (upper side) of the second-stage pump chamber 50b. Then, the process gas flowing into the second stage pump chamber 50b from the inlet side passes through the inside of the second stage pump chamber 50b, and then flows into the second gas passage 72b from the outlet side of the second stage pump chamber 50b. Then, after flowing upward along the second gas passage 72b, it reaches the inlet side of the third stage pump chamber 50c. In this way, the process gas further sequentially passes through the third to sixth stage pump chambers 50c to 50f, and then is exhausted to the outside through the exhaust port 54b from the outlet side of the sixth stage pump chamber 50f.

この例によれば、ポンプケーシング５６の外胴５４を、内部にガス通路７２ａ〜７２ｅを有する二重壁構造とすることで、このガス通路７２ａ〜７２ｅに沿って流れる高温のプロセスガスを通して、ポンプ室５０ａ〜５０ｆの内部と外部とをより確実に遮断し、これによって、ポンプ内部が低温となって、プロセスガスに含まれる昇華性物質等が気体から固体となってポンプ内部（ポンプケーシング内周面）に付着してしまうことを防止することができる。特に、高温のプロセスガスがガス通路７２ａ〜７２ｅに沿って各ポンプ室５０ａ〜５０ｅの出口側（下側）から次の段の入口側（上側）に向かって流れるようにすることで、この高温のプロセスガスでポンプ室５０ａ〜５０ｆを有効に加熱することができる。   According to this example, the outer cylinder 54 of the pump casing 56 has a double-wall structure having gas passages 72a to 72e inside, so that the pump passes through the hot process gas flowing along the gas passages 72a to 72e. The interior and exterior of the chambers 50a to 50f are more reliably shut off, whereby the inside of the pump is cooled to a low temperature, and the sublimable substances contained in the process gas are turned into solids from the gas. Can be prevented from adhering to the surface. In particular, the high-temperature process gas flows along the gas passages 72a to 72e from the outlet side (lower side) of each pump chamber 50a to 50e toward the inlet side (upper side) of the next stage. The pump chambers 50a to 50f can be effectively heated with the process gas.

この例では、ポンプケーシング５６の外胴５４の吸気口５４ａ及び排気口５４ｂを除く領域の外周部を略円筒状の保温ジャケット７４で一体的に包囲している。これによって、ポンプ室５０ａ〜５０ｆの内部と外部とを保温ジャケット７４によっても遮断して、ポンプ室５０ａ〜５０ｆの保温効果を高めることができる。   In this example, an outer peripheral portion of a region of the outer casing 54 of the pump casing 56 excluding the intake port 54 a and the exhaust port 54 b is integrally surrounded by a substantially cylindrical heat retaining jacket 74. Thereby, the inside and the outside of the pump chambers 50a to 50f can be blocked by the heat insulation jacket 74, and the heat insulation effect of the pump chambers 50a to 50f can be enhanced.

ポンプケーシング５６の端壁６４ａ，６４ｂの側方には、サイドパネル８０ａ，８０ｂがそれぞれ配置され、このサイドパネル８０ａ，８０ｂにそれぞれ取り付けた軸受ハウジング８２ａ，８２ｂ内に収容した軸受８４ａ，８４ｂを介して、回転軸６０がその両端において回転自在に支承されている。更に、サイドパネル８０ａ，８０ｂの側方に位置して、内部に潤滑油を溜める潤滑油ハウジング８８ａ，８８ｂが配置され、一方の潤滑油ハウジング８８ｂの側方にモータ５８のモータハウジングが連結されている。サイドパネル８０ａ，８０ｂには、サイドパネル８０ａ，８０ｂの回転軸６０の挿通部にＮ２ガス等のパージガスを供給して、ポンプ室５０ａ〜５０ｆ内に流入したプロセスガスが軸受８４ａ，８４ｂの方向に流出することを防止するためのパージガス通路９０ａ，９０ｂが設けられ、これによって、サイドパネル８０ａ，８０ｂと回転軸６０との間に、接触による摩耗を防止した非接触シールが構成されている。なお、パージガス通路９０ｂを流れたパージガスは、大気開放室５２内にも流入する。 Side panels 80a and 80b are respectively arranged on the sides of the end walls 64a and 64b of the pump casing 56. The bearings 84a and 84b are housed in bearing housings 82a and 82b attached to the side panels 80a and 80b, respectively. Thus, the rotary shaft 60 is rotatably supported at both ends thereof. Further, lubricating oil housings 88a and 88b for storing lubricating oil are disposed inside the side panels 80a and 80b, and the motor housing of the motor 58 is connected to the side of one lubricating oil housing 88b. Yes. In the side panels 80a and 80b, a purge gas such as N 2 gas is supplied to the insertion part of the rotating shaft 60 of the side panels 80a and 80b, and the process gas flowing into the pump chambers 50a to 50f is directed to the bearings 84a and 84b. Purge gas passages 90a and 90b are provided for preventing the gas from flowing out, thereby forming a non-contact seal between the side panels 80a and 80b and the rotary shaft 60 to prevent wear due to contact. The purge gas that has flowed through the purge gas passage 90 b also flows into the atmosphere release chamber 52.

この例では、最も高圧となる第６段ポンプ室（最終段ポンプ室）５０ｆ側の端壁６４ｂと該端壁６４ｂに隣接して配置されるサイドパネル８０ｂとの間に、排気口５４ｂに連通して大気に開放される大気開放室５２を設け、軸受８４ｂを収納した軸受ハウジング８２ｂを内部に収納した潤滑油ハウジング８８ｂを該サイドパネル８０ｂに取り付けている。これにより、たとえ第６段ポンプ室（最終段ポンプ室）５０ｆの内部圧力が変化しても、大気開放室５２の側方に位置して内部に軸受８４ｂを収容している室、つまりサイドパネル８０ｂと潤滑油ハウジング８８ｂで周囲を包囲された室Ｒの内部が常にほぼ大気圧となるようにすることができる。これによって、ポンプ室５０ａ〜５０ｆ内に流入したプロセスガスが、大気開放室５２の側方に位置して内部に軸受８４ｂを収容している室Ｒの内部に漏れてしまうことをより確実に防止して、軸受８４ｂをプロセスガスから保護することができる。   In this example, the exhaust port 54b communicates between the end wall 64b on the side of the sixth-stage pump chamber (final stage pump chamber) 50f that has the highest pressure and the side panel 80b that is disposed adjacent to the end wall 64b. Then, an air release chamber 52 that is open to the atmosphere is provided, and a lubricating oil housing 88b that houses therein a bearing housing 82b that houses a bearing 84b is attached to the side panel 80b. Thereby, even if the internal pressure of the sixth-stage pump chamber (final-stage pump chamber) 50f changes, the chamber is located on the side of the atmosphere release chamber 52 and accommodates the bearing 84b, that is, the side panel. The inside of the chamber R surrounded by 80b and the lubricating oil housing 88b can always be at almost atmospheric pressure. As a result, the process gas that has flowed into the pump chambers 50a to 50f is more reliably prevented from leaking into the chamber R which is located on the side of the atmosphere release chamber 52 and accommodates the bearing 84b therein. Thus, the bearing 84b can be protected from the process gas.

これは、以下の理由による。回転軸６０とサイドパネル８０ｂとの間を非接触シールでシールし、第６段ポンプ室（最終段ポンプ室）５０ｆとサイドパネル８０ｂとが互いに隣接して配置されている場合、すなわち、大気開放室５２がない場合、サイドパネル８０ｂの側方に位置して内部に軸受８４ｂを収容している室、つまりサイドパネル８０ｂと潤滑油ハウジング８８ｂで周囲を包囲された室Ｒの内部圧力は、第６段ポンプ室（最終段ポンプ室）５０ｆのほぼ平均圧力となる。例えば、第６段ポンプ室５０ｆの出口側圧力はほぼ大気圧（７６０Ｔｏｒｒ）であるが、入口側圧力が大気圧より低い圧力、仮に２００Ｔｏｒｒである場合、サイドパネル８０ｂと潤滑油ハウジング８８ｂで周囲を包囲された室Ｒの内部圧力は、ほぼ４８０Ｔｏｒｒ（＝（７６０＋２００）／２）となる。そして、真空チャンバ側からのプロセスガスの流入により第６段ポンプ室５０ｆの入口側圧力が２００Ｔｏｒｒから３００Ｔｏｒｒに変化（上昇）すると、第６段ポンプ室５０ｆの平均圧力も５３０Ｔｏｒｒ（＝（７６０＋３００）／２）となり、サイドパネル８０ｂと潤滑油ハウジング８８ｂで周囲を包囲された室Ｒの内部圧力が５３０Ｔｏｒｒに上昇するまで、プロセスガスを含んだガスが、第６段ポンプ室５０ｆからサイドパネル８０ｂと回転軸６０の隙間を通って室Ｒに流入する。   This is due to the following reason. When the rotary shaft 60 and the side panel 80b are sealed with a non-contact seal, the sixth stage pump chamber (final stage pump chamber) 50f and the side panel 80b are disposed adjacent to each other, that is, open to the atmosphere. When the chamber 52 is not provided, the internal pressure of the chamber R which is located on the side of the side panel 80b and accommodates the bearing 84b therein, that is, the chamber R surrounded by the side panel 80b and the lubricating oil housing 88b is The average pressure in the six-stage pump chamber (final stage pump chamber) 50f is obtained. For example, the outlet side pressure of the sixth stage pump chamber 50f is almost atmospheric pressure (760 Torr), but if the inlet side pressure is lower than atmospheric pressure, ie, 200 Torr, the side panel 80b and the lubricant housing 88b surround the periphery. The internal pressure of the enclosed chamber R is approximately 480 Torr (= (760 + 200) / 2). When the pressure on the inlet side of the sixth stage pump chamber 50f changes (increases) from 200 Torr to 300 Torr due to the inflow of process gas from the vacuum chamber side, the average pressure in the sixth stage pump chamber 50f also increases to 530 Torr (= (760 + 300) / 2) until the internal pressure of the chamber R surrounded by the side panel 80b and the lubricant housing 88b rises to 530 Torr, the gas containing the process gas rotates from the sixth-stage pump chamber 50f to the side panel 80b. It flows into the chamber R through the gap of the shaft 60.

これに対して、この例のように、第６段ポンプ室（最終段ポンプ室）５０ｆ側の端壁６４ｂと該端壁６４ｂに隣接して配置されるサイドパネル８０ｂとの間に、排気口５４ｂに連通して大気に開放される大気開放室５２を設けると、前述のように、第６段ポンプ室（最終段ポンプ室）５０ｆの内部圧力（平均圧力）が変化（上昇）しても、大気開放室５２の圧力は大気圧から殆ど変化せず、また、サイドパネル８０ｂの側方に位置して内部に軸受８４ｂを収容している室、つまりサイドパネル８０ｂと潤滑油ハウジング８８ｂで周囲を包囲された室Ｒの内部圧力も、殆ど影響を受けることなく、ほぼ大気圧のままに維持される。   On the other hand, as in this example, an exhaust port is provided between the end wall 64b on the side of the sixth stage pump chamber (final stage pump chamber) 50f and the side panel 80b disposed adjacent to the end wall 64b. If the air release chamber 52 that communicates with the air b and is opened to the atmosphere is provided, as described above, even if the internal pressure (average pressure) of the sixth stage pump chamber (final stage pump chamber) 50f changes (rises). The pressure in the atmosphere opening chamber 52 hardly changes from the atmospheric pressure, and is located around the side panel 80b and the lubricating oil housing 88b. The internal pressure of the chamber R surrounded by the chamber R is also hardly affected and is maintained at almost atmospheric pressure.

上述のように構成された真空ポンプ１０にあっては、ブースタポンプ１２のモータ２４及びメインポンプ１４のモータ５８を駆動して、真空チャンバの内部に導入されたプロセスガスをブースタポンプ１２及びメインポンプ１４で真空排気する。この時、大気開放室５２の側方に位置して内部に軸受８４ｂを収容している室、つまりサイドパネル８０ｂと潤滑油ハウジング８８ｂで周囲を包囲された室Ｒの内部が常にほぼ大気圧となるようにすることで、ポンプ内部に流入したプロセスガスが軸受側に漏れることをより確実に防止して、軸受をプロセスガスから保護できる。   In the vacuum pump 10 configured as described above, the motor 24 of the booster pump 12 and the motor 58 of the main pump 14 are driven, and the process gas introduced into the vacuum chamber is supplied to the booster pump 12 and the main pump. 14 is evacuated. At this time, the chamber which is located on the side of the air release chamber 52 and accommodates the bearing 84b therein, that is, the interior of the chamber R surrounded by the side panel 80b and the lubricating oil housing 88b is always at almost atmospheric pressure. By doing so, the process gas flowing into the pump can be more reliably prevented from leaking to the bearing side, and the bearing can be protected from the process gas.

これまで本発明の一実施形態について説明したが、本発明は上述の実施形態に限定されず、その技術的思想の範囲内において種々異なる形態にて実施されてよいことは言うまでもない。例えば、上記実施形態では、多段ルーツ式真空ポンプに適用した例を示しているが、単段ルーツ式真空ポンプに適用してもよく、またクロー式真空ポンプの他に、例えばルーツ式、クロー式、スクリュー式の内、２方式もしくは３方式全てを同一回転軸上で組合せた真空ポンプに適用することもできる。   Although one embodiment of the present invention has been described so far, it is needless to say that the present invention is not limited to the above-described embodiment, and may be implemented in various forms within the scope of the technical idea. For example, in the above-described embodiment, an example is shown in which the present invention is applied to a multi-stage roots vacuum pump. However, the present invention may be applied to a single-stage roots vacuum pump. Also, it can be applied to a vacuum pump in which two or three of screw types are combined on the same rotating shaft.

１０ 真空ポンプ
１２ ブースタポンプ
１４ メインポンプ
１６ 連絡配管
１８ ポンプ室
２０ 外胴
２０ａ 吸気口
２０ｂ 排気口
２２ ポンプケーシング
２４ モータ
２６ 回転軸
２８ ロータ
３０ ヒータジャケット
３２ａ，３２ｂ サイドパネル
３６ａ，３６ｂ 軸受
４０ａ，４０ｂ 潤滑油ハウジング
４２ａ，４２ｂ パージガス通路
５０ａ〜５０ｆ ポンプ室
５２ 大気開放室
５４ 外胴
５４ａ 吸気口
５４ｂ 排気口
５６ ポンプケーシング
５８ モータ
６０ 回転軸
６２ａ〜６２ｆ ロータ
６４ａ，６４ｂ 端壁
６６ａ〜６６ｅ 仕切壁
６８ 内壁
７０ 外壁
７２ａ〜７２ｅ ガス通路
７４ 保温ジャケット
８０ａ，８０ｂ サイドパネル
８４ａ，８４ｂ 軸受
８８ａ，８８ｂ 潤滑油ハウジング
９０ａ，９０ｂ パージガス通路 DESCRIPTION OF SYMBOLS 10 Vacuum pump 12 Booster pump 14 Main pump 16 Connection piping 18 Pump chamber 20 Outer trunk 20a Inlet 20b Exhaust outlet 22 Pump casing 24 Motor 26 Rotating shaft 28 Rotor 30 Heater jacket 32a, 32b Side panel 36a, 36b Bearing 40a, 40b Lubrication Oil housings 42a, 42b Purge gas passages 50a-50f Pump chamber 52 Atmospheric release chamber 54 Outer cylinder 54a Inlet port 54b Exhaust port 56 Pump casing 58 Motor 60 Rotating shaft 62a-62f Rotors 64a, 64b End walls 66a-66e Partition wall 68 Inner wall 70 Outer walls 72a to 72e Gas passage 74 Thermal insulation jackets 80a and 80b Side panels 84a and 84b Bearings 88a and 88b Lubricating oil housings 90a and 90b Purge gas passage

Claims (3)

吸気口と排気口とを有し、互いに連通し、仕切壁で仕切られた複数段のポンプ室を内部に備えたポンプケーシングと、
両端を軸受で回転自在に支承されて前記ポンプケーシングの長さ方向に沿って配置される回転軸と、
前記ポンプ室内にそれぞれ収容され、前記回転軸に連結されて該回転軸の回転に伴って回転する複数のロータとを有し、
最終段ポンプ室は、吸気側の仕切壁と排気側の端壁によって形成され、
前記排気側の端壁の側方にはサイドパネルが設けられており、
前記端壁と前記サイドパネルの間には、前記排気口に連通し大気に開放させた大気開放室が設けられており、
前記ポンプケーシングは、内壁と該内壁と所定間隔離間して配置される外壁とを備えた二重壁構造を有していることを特徴とする真空ポンプ。 And a intake port outlet, communicating with each other, a pump casing having a pump chamber of a plurality of stages which are partitioned by a partition wall inside,
A rotary shaft that is rotatably supported by bearings at both ends and arranged along the length direction of the pump casing;
A plurality of rotors respectively housed in the pump chamber, coupled to the rotating shaft and rotating with the rotation of the rotating shaft;
The final stage pump chamber is formed by an intake side partition wall and an exhaust side end wall,
A side panel is provided on the side of the end wall on the exhaust side,
Between said side panels and said end wall is the air release chamber is opened to the atmosphere communication is provided in the exhaust port,
2. The vacuum pump according to claim 1, wherein the pump casing has a double wall structure including an inner wall and an outer wall arranged at a predetermined distance from the inner wall . 前記サイドパネルの内部には前記回転軸が挿通されており、該回転軸の挿通部にパージガスを供給するパージガス通路が設けられていることを特徴とする請求項１記載の真空ポンプ。 The inside of the side panel is inserted through the rotary shaft, according to claim 1 Symbol placement of the vacuum pump, characterized in that the purge gas passage for supplying purge gas into the insertion portion of the rotary shaft. 前記大気開放室は一定の幅を有していることを特徴とする請求項１または２に記載の真空ポンプ。  The vacuum pump according to claim 1, wherein the open air chamber has a certain width.
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