JPS62168994A - High vacuum exhaust device - Google Patents
High vacuum exhaust deviceInfo
- Publication number
- JPS62168994A JPS62168994A JP60296830A JP29683085A JPS62168994A JP S62168994 A JPS62168994 A JP S62168994A JP 60296830 A JP60296830 A JP 60296830A JP 29683085 A JP29683085 A JP 29683085A JP S62168994 A JPS62168994 A JP S62168994A
- Authority
- JP
- Japan
- Prior art keywords
- deflection member
- molecules
- suction port
- high vacuum
- turbo
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000005086 pumping Methods 0.000 claims 2
- 238000009792 diffusion process Methods 0.000 abstract description 5
- 238000001816 cooling Methods 0.000 abstract description 3
- 239000007789 gas Substances 0.000 description 14
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 230000000694 effects Effects 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000003507 refrigerant Substances 0.000 description 2
- 240000004307 Citrus medica Species 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/40—Casings; Connections of working fluid
- F04D29/52—Casings; Connections of working fluid for axial pumps
- F04D29/54—Fluid-guiding means, e.g. diffusers
- F04D29/541—Specially adapted for elastic fluid pumps
- F04D29/545—Ducts
- F04D29/547—Ducts having a special shape in order to influence fluid flow
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D19/00—Axial-flow pumps
- F04D19/02—Multi-stage pumps
- F04D19/04—Multi-stage pumps specially adapted to the production of a high vacuum, e.g. molecular pumps
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/58—Cooling; Heating; Diminishing heat transfer
- F04D29/582—Cooling; Heating; Diminishing heat transfer specially adapted for elastic fluid pumps
- F04D29/5826—Cooling at least part of the working fluid in a heat exchanger
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2250/00—Geometry
- F05D2250/50—Inlet or outlet
- F05D2250/51—Inlet
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Thermal Sciences (AREA)
- Non-Positive Displacement Air Blowers (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
この発明は、気体分子に特定方向の運動量を与えて高真
空排気を行う真空排気装置に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vacuum evacuation device that performs high vacuum evacuation by imparting momentum in a specific direction to gas molecules.
こ従来の技術〕
高真空排気を行うために、気体分子に特定の方向の運動
量を与える機能を機械的手段により行わせるターボ分子
ポンプを利用する排気装置が知られているが、その場合
のターボ分子ポンプの構成は概略的には第５図に示すと
おりである。即ち、このターボ分子ポンプは回転翼車２
１と周定Ｍ２２とが所定の関係で組み合わせ配置され、
回転翼車２１がモータ２３により高速で回転されること
により、ターボ機能を形成させ、吸気口２４かろ吸入さ
れた気体分子に特定方向即ち、この場合、軸芯方向Ａの
運動量を与える真空ポンプであって、運動量が与えられ
た気体分子は圧縮されてかり排気口２５にまとまり、油
回転ポンプ等の補助ポンプ（図示せず）を経て大気中に
排出されるようになっている。[Prior Art] In order to perform high vacuum evacuation, an evacuation device is known that uses a turbomolecular pump that mechanically performs the function of imparting momentum to gas molecules in a specific direction. The structure of the molecular pump is schematically shown in FIG. That is, this turbomolecular pump has a rotary impeller 2.
1 and the circumferential M22 are arranged in combination in a predetermined relationship,
The rotary impeller 21 is rotated at high speed by the motor 23 to form a turbo function, and is a vacuum pump that gives momentum to the gas molecules sucked in through the intake port 24 in a specific direction, that is, in this case, in the axial direction A. The gas molecules given momentum are compressed and collected at the exhaust port 25, and are discharged into the atmosphere via an auxiliary pump (not shown) such as an oil rotary pump.
ところで、このようなターボ分子ポンプは、吸気口２４
を吸気側前方即ち第５図上方から見た第６図から明らか
なように、回転翼車２１の吸気口側端面２６は、回転翼
車２１及び固定翼２２と対応する翼群領域２７Ａと翼が
設けられていない領域２７Ｂとを含んでいる。一般に、
分子流領域では、翼群領域２７Ａに飛び込んだ気体分子
のみに運動量が与えられ排気される。従って、この端面
２６の領域２７Ｂに飛び込んだ気体分子は、第５図にお
いて矢印Ｂで示すような反射したり、また吸着されたの
ち再蒸発したりして、吸気口２４への逆拡散が発生する
。このような現象によって、高真空排気装置は、排気連
層が低下し、到達真空度が充分に高くならない問題点が
あった。By the way, such a turbo molecular pump has an intake port 24.
As is clear from FIG. 6 when viewed from the front of the intake side, that is, from the top of FIG. It includes a region 27B where no is provided. in general,
In the molecular flow region, only the gas molecules that have jumped into the blade group region 27A are given momentum and are exhausted. Therefore, the gas molecules that have jumped into the region 27B of the end face 26 are reflected as shown by arrow B in FIG. do. Due to this phenomenon, the high vacuum evacuation apparatus has a problem in that the evacuation layer is reduced and the ultimate vacuum cannot be sufficiently high.
この発明は、分子流領域において端面による吸気口への
逆拡散を防止し、到達真空度を従来より高くできる高真
空排気装置を堤供するものである。The present invention provides a high-vacuum evacuation device that prevents back-diffusion toward the inlet port due to the end face in the molecular flow region and can achieve a higher degree of vacuum than ever before.
回転翼と固定翼によるターボ機能によって気体分子に特
定方向の運動量を与えて排気を行うターボ分子ポンプ機
構の吸気口近傍に、その尖端部が吸気口側前方に向けら
れ、且つポンプ機構の軸芯方向縦断面形状がくさび状を
なした偏向部材を配設する。この偏向部材は、端面と近
接して設けるか、或いは端面に一体的に取り付ける。更
に、必要により、偏向部材の表面を冷却する。Near the intake port of a turbo-molecular pump mechanism that gives momentum to gas molecules in a specific direction and exhausts gas using the turbo function of rotary blades and fixed blades, its tip is directed forward toward the intake port side, and the axis of the pump mechanism A deflection member having a wedge-shaped vertical cross-section is provided. This deflection member is provided close to the end surface or is integrally attached to the end surface. Furthermore, if necessary, the surface of the deflection member is cooled.
偏向部材のくさび形状によって、吸気口からの気体分子
は、分子に特定方向の運動量を与える領域のみに導かれ
る。即ち、流入分子流の逆拡散の原因となる端面がなく
なる。また、偏向部材の表面を冷却すると、この冷却面
に気体分子が吸着され、再蒸発が抑制される。The wedge shape of the deflection member directs gas molecules from the inlet only to regions that impart momentum to the molecules in a particular direction. That is, there is no end face that causes back diffusion of the incoming molecular flow. Moreover, when the surface of the deflection member is cooled, gas molecules are adsorbed on this cooling surface, and re-evaporation is suppressed.
以下、この発明の構成を第１図に従って説明する。図に
おいて、ｌは、回転翼車２の周囲に設けられた回転翼部
で、円筒状のケース３の内面に固定された固定翼４に対
応されている。多数の回転翼部１及び固定翼４が交互に
配列され、この両者の相対的な高速回転によってターボ
機能が形成され、気体分子に特定方向の運動量を与える
。そして、この配列の上方に吸気口５が設けられると共
に、その下方に排気口が設けられる。The configuration of the present invention will be explained below with reference to FIG. In the figure, l denotes a rotor blade section provided around the rotor wheel 2, which corresponds to a fixed blade 4 fixed to the inner surface of the cylindrical case 3. A large number of rotary blade sections 1 and fixed blades 4 are arranged alternately, and a turbo function is formed by the relative high speed rotation of the two, giving momentum to gas molecules in a specific direction. An intake port 5 is provided above this arrangement, and an exhaust port is provided below.
回転翼車２は、ケース３内底部から立設された七−タフ
の駆動軸８の一端に固着されている。モータ７は、一般
的には、駆動軸８にロータマグネットが固着されたアラ
クーロータ型の構成とされている。The rotor wheel 2 is fixed to one end of a seven-tough drive shaft 8 that stands up from the inner bottom of the case 3 . The motor 7 generally has an Araku rotor type structure in which a rotor magnet is fixed to a drive shaft 8.
さて、この発明では、以上の構成において、吸気口５の
近傍に軸芯方向縦断面形状がくさび４にの偏向部材９が
設置される。この偏向部材９は、その尖端部即ち頂部が
吸気口５前方即ち図において吸気口上方に向けられて設
置されている。偏向部材９の底面の大きさは、回転翼車
２の回転翼部１と固定翼４とからなる翼群領域を被わな
い程度とされる。偏向部材９の頂部は、吸気口５の端面
より吸気側前方に突出しているが、端面より下方になる
ように配置しても良い。Now, in the present invention, in the above configuration, a deflection member 9 having a wedge 4 longitudinal cross-sectional shape in the axial direction is installed near the intake port 5. This deflection member 9 is installed with its tip, or top, facing in front of the intake port 5, that is, above the intake port in the drawing. The size of the bottom surface of the deflection member 9 is set to such an extent that it does not cover the blade group region consisting of the rotary blade portion 1 and the fixed blades 4 of the rotary blade wheel 2 . Although the top of the deflection member 9 projects forward on the intake side from the end surface of the intake port 5, it may be arranged below the end surface.
第２図は、この発明をターボ分子ポンプ単体に実施した
例を示し、ケース３に偏向部材９が片持ち形で保持され
ている。尚、第２図の場合は、偏向部材９は、中空構造
とされ、その内部に注入孔１０及び排出孔１１を通じて
液体窒素等の冷媒が注入され、その表面は、使用される
冷媒に応した温度に冷却されるように構成されている。FIG. 2 shows an example in which the present invention is applied to a single turbo-molecular pump, in which a deflection member 9 is held in a cantilevered manner by a case 3. In the case of FIG. 2, the deflection member 9 has a hollow structure, into which a refrigerant such as liquid nitrogen is injected through an injection hole 10 and a discharge hole 11, and its surface has a shape corresponding to the refrigerant used. It is configured to be cooled to a temperature.
なお、６は排気口である。Note that 6 is an exhaust port.
第３図は、この発明の池の実施例を示す。即ち、この他
の実施例では、偏向部材９をターボ分子ポンプを取り付
ける排気系具体的には、配管１２に保持させた例を示し
ている。更に、この変形の延長として偏向部材９を被排
気室のフレームに保持させるようにすることもできる。FIG. 3 shows an embodiment of the pond of the invention. That is, in this other embodiment, an example is shown in which the deflection member 9 is held in an exhaust system to which a turbo molecular pump is attached, specifically, in a pipe 12. Furthermore, as an extension of this modification, the deflection member 9 can be held by the frame of the chamber to be evacuated.
これらの実施例は、この発明をターボ分子ポンプ単体と
して構成しない例である。These embodiments are examples in which the present invention is not constructed as a single turbomolecular pump.
また、第４図は、この発明の更に他の実施例を示す。即
ち第４図に示される構成は、この発明をターボ分子ポン
プの単体として構成した実施例を示し、回転翼車２の上
側端面２Ａに偏向部材９が固着されている。従って、偏
向部材９は、回転翼車２と一体に回転し、その外周面形
状によって、気体分子の逆拡散が防止され真空度の向上
が図られる。Further, FIG. 4 shows still another embodiment of the present invention. That is, the configuration shown in FIG. 4 shows an embodiment in which the present invention is configured as a single turbo-molecular pump, and a deflection member 9 is fixed to the upper end surface 2A of the rotary impeller 2. Therefore, the deflection member 9 rotates together with the rotary impeller 2, and the shape of its outer peripheral surface prevents back diffusion of gas molecules and improves the degree of vacuum.
この発明の特徴は、以上説明した通りであるが、上記並
びに図示例に限定されるものではなく、特に、偏向部材
９の形状は、円錐に限らず、角錐等の軸芯方向縦断面形
状がくさび状のものであれば良く、頂点から延びる二辺
が直線でなく、くの字形等でも良い。更に、第４図実施
例の場合、偏向部材を液体窒素等により、冷却すること
は困難であるが、加熱化を防止するための柚巡回による
冷却は可能である。ただこの発明においては、偏向部材
表面を冷却しない実施例をも包含する。また、この発明
は、回転軸が水平左回のターボ分子ポンプ置溝を有する
装置に対しても通用可能である。The features of the present invention are as described above, but are not limited to the above and illustrated examples. In particular, the shape of the deflection member 9 is not limited to a cone, but may have an axial longitudinal cross-sectional shape such as a pyramid. It may be wedge-shaped, and the two sides extending from the apex may not be straight lines, but may be dogleg-shaped. Further, in the case of the embodiment shown in FIG. 4, it is difficult to cool the deflection member with liquid nitrogen or the like, but it is possible to cool the deflection member with a citron cycle to prevent heating. However, the present invention also includes embodiments in which the surface of the deflection member is not cooled. Further, the present invention can also be applied to an apparatus having a turbo-molecular pump groove in which the rotation axis is horizontally rotated to the left.
この発明シよ以上詳述し１ことおりであるから、偏向部
材９によって、吸気口５から流入した気体分子が反射す
ることが防止され、到達真空度を従来に比してより斉（
することができる。また、偏向部材９を冷却面を有する
ものとすれば、気体分子の再蒸発が抑制され、真空度を
工り高（できる。Since this invention has been described in detail above, the deflection member 9 prevents the gas molecules flowing in from the intake port 5 from being reflected, and the degree of vacuum achieved is more uniform (compared to the prior art).
can do. Moreover, if the deflection member 9 has a cooling surface, re-evaporation of gas molecules is suppressed and the degree of vacuum can be increased.
特に、ターボ分子ポンプ４ｉ！１構と偏向部材との結合
によるものであるから、偏向部材の同定位置に制限がな
くターボ分子ポンプを利用した多用的な高真空排気装置
を提供することができる。Especially the turbo molecular pump 4i! Since it is based on the combination of one structure and the deflection member, there is no restriction on the identification position of the deflection member, and a versatile high vacuum evacuation device using a turbo-molecular pump can be provided.
第１図はこの発明の原理的構成を示すＹＪ断面図、第２
図はこの発明の具体的構成を示す図、第３図及び第４図
は夫々この発明の池の実施例の縦断面図、第５図及び第
６図は従来のターボ分子ポンプの説明に用いる断面図及
び平面図である。
図面における主要な符号の説明
１：回転翼部、 ２：回転翼車、 ３：ケース、４：固
定翼、 ５：吸気口、 ６；排気口、７：モータ、 ８
：駆動軸、 ９：偏向部材。Figure 1 is a YJ sectional view showing the basic configuration of this invention;
The figure shows a specific configuration of the present invention, Figures 3 and 4 are longitudinal sectional views of an embodiment of the pond of the present invention, and Figures 5 and 6 are used to explain a conventional turbo-molecular pump. They are a sectional view and a plan view. Explanation of main symbols in the drawings 1: Rotating blade section, 2: Rotary blade wheel, 3: Case, 4: Fixed blade, 5: Intake port, 6: Exhaust port, 7: Motor, 8
: Drive shaft, 9: Deflection member.
Claims (4)
ーボ機能により気体分子に特定方向の運動量を与えるよ
うにしたターボ分子ポンプ機構と、その尖端部が吸気側
前方に向けられ、且つ上記ターボ分子ポンプ機構の軸芯
方向縦断面形状がくさび状をなした偏向部材とを具備し
、上記偏向部材を上記吸気口近傍に配設したことを特徴
とする高真空排気装置。(1) A turbo molecular pump mechanism that rotates a rotary impeller at high speed relative to a fixed blade and uses its turbo function to impart momentum in a specific direction to gas molecules, and its tip is directed forward on the intake side, and A high vacuum evacuation device comprising: a deflection member having a wedge-shaped longitudinal cross-sectional shape in the axial direction of the turbo-molecular pump mechanism, the deflection member being disposed near the intake port.
る特許請求の範囲第１項記載の高真空排気装置。(2) The high vacuum evacuation device according to claim 1, wherein the surface of the deflection member is cooled.
たことを特徴とする特許請求の範囲第１項又は第２項記
載の高真空排気装置。(3) The high vacuum pumping device according to claim 1 or 2, wherein the deflection member is installed as a separate member from the rotary impeller.
れたことを特徴とする特許請求の範囲第１項又は第２項
記載の高真空排気装置。(4) The high vacuum pumping device according to claim 1 or 2, wherein the deflection member is attached to the end of the rotary impeller on the side of the intake port.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60296830A JPS62168994A (en) | 1985-12-26 | 1985-12-26 | High vacuum exhaust device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60296830A JPS62168994A (en) | 1985-12-26 | 1985-12-26 | High vacuum exhaust device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS62168994A true JPS62168994A (en) | 1987-07-25 |
Family
ID=17838709
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60296830A Pending JPS62168994A (en) | 1985-12-26 | 1985-12-26 | High vacuum exhaust device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62168994A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH025792A (en) * | 1988-03-07 | 1990-01-10 | Toshiba Corp | Turbo molecular pump and its operating method |
| US4926648A (en) * | 1988-03-07 | 1990-05-22 | Toshiba Corp. | Turbomolecular pump and method of operating the same |
| US5062271A (en) * | 1989-05-09 | 1991-11-05 | Kabushiki Kaisha Toshiba | Evacuation apparatus and evacuation method |
| JPH07279888A (en) * | 1994-04-07 | 1995-10-27 | Applied Materials Inc | Evacuator |
| US5483803A (en) * | 1993-06-16 | 1996-01-16 | Helix Technology Corporation | High conductance water pump |
| USRE36610E (en) * | 1989-05-09 | 2000-03-14 | Kabushiki Kaisha Toshiba | Evacuation apparatus and evacuation method |
| JP2002005079A (en) * | 2000-05-15 | 2002-01-09 | Pfeiffer Vacuum Gmbh | Gas friction pump |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58155297A (en) * | 1981-12-14 | 1983-09-14 | ユルトラ・ツエントリフユ−ゲ・ネ−デルランド・ナ−ムロ−ゼ・ヴエノ−トチヤツプ | High-vacuum molecular pump |
| JPS6081485A (en) * | 1983-10-11 | 1985-05-09 | Tokuda Seisakusho Ltd | Vacuum exhauster |
-
1985
- 1985-12-26 JP JP60296830A patent/JPS62168994A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58155297A (en) * | 1981-12-14 | 1983-09-14 | ユルトラ・ツエントリフユ−ゲ・ネ−デルランド・ナ−ムロ−ゼ・ヴエノ−トチヤツプ | High-vacuum molecular pump |
| JPS6081485A (en) * | 1983-10-11 | 1985-05-09 | Tokuda Seisakusho Ltd | Vacuum exhauster |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH025792A (en) * | 1988-03-07 | 1990-01-10 | Toshiba Corp | Turbo molecular pump and its operating method |
| US4926648A (en) * | 1988-03-07 | 1990-05-22 | Toshiba Corp. | Turbomolecular pump and method of operating the same |
| US5062271A (en) * | 1989-05-09 | 1991-11-05 | Kabushiki Kaisha Toshiba | Evacuation apparatus and evacuation method |
| USRE36610E (en) * | 1989-05-09 | 2000-03-14 | Kabushiki Kaisha Toshiba | Evacuation apparatus and evacuation method |
| US5483803A (en) * | 1993-06-16 | 1996-01-16 | Helix Technology Corporation | High conductance water pump |
| JPH07279888A (en) * | 1994-04-07 | 1995-10-27 | Applied Materials Inc | Evacuator |
| JP2002005079A (en) * | 2000-05-15 | 2002-01-09 | Pfeiffer Vacuum Gmbh | Gas friction pump |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5637919B2 (en) | Compound vacuum pump | |
| US8235678B2 (en) | Multi-stage vacuum pumping arrangement | |
| JP5913109B2 (en) | Vacuum pump | |
| JP4173637B2 (en) | Friction vacuum pump with stator and rotor | |
| JP2011106466A (en) | Pumping arrangement | |
| JP2000337290A (en) | Vacuum pump | |
| JP3047292B1 (en) | Turbo molecular pump and vacuum device | |
| US6672827B2 (en) | Vacuum pump | |
| JPS62168994A (en) | High vacuum exhaust device | |
| JP5027352B2 (en) | Improvement of vacuum pump | |
| WO1995028571A1 (en) | Molecular pump | |
| US20060177300A1 (en) | Baffle configurations for molecular drag vacuum pumps | |
| JPH1089284A (en) | Turbo-molecular pump | |
| JP2002168192A (en) | Vacuum pump | |
| JPS6131695A (en) | Turbo molecular pump | |
| US20230042886A1 (en) | Vacuum pump, vacuum pump set for evacuating a semiconductor processing chamber and method of evacuating a semiconductor processing chamber | |
| JPS6355396A (en) | Turbo vacuum pump | |
| JP2015124616A (en) | Vacuum pump | |
| JPH11107979A (en) | Turbo-molecular pump | |
| JPS61283794A (en) | Turbo molecular pump | |
| JPH05141389A (en) | Vacuum pump | |
| JPH11159493A (en) | Molecular drag compressor having finned rotor structure | |
| JP2802035B2 (en) | Vacuum exhaust device | |
| JP3787278B2 (en) | Differential exhaust method and apparatus | |
| JPS6125994A (en) | Turbo-molecular pump and operating method thereof |