US20100021324A1 - Vacuum pump - Google Patents

Vacuum pump Download PDF

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Publication number
US20100021324A1
US20100021324A1 US12/460,738 US46073809A US2010021324A1 US 20100021324 A1 US20100021324 A1 US 20100021324A1 US 46073809 A US46073809 A US 46073809A US 2010021324 A1 US2010021324 A1 US 2010021324A1
Authority
US
United States
Prior art keywords
gas
shaft
vacuum pump
pumping
bearing
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.)
Abandoned
Application number
US12/460,738
Other languages
English (en)
Inventor
Armin Conrad
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Pfeiffer Vacuum GmbH
Original Assignee
Pfeiffer Vacuum GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Pfeiffer Vacuum GmbH filed Critical Pfeiffer Vacuum GmbH
Assigned to PFEIFFER VACUUM GMBH reassignment PFEIFFER VACUUM GMBH ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: CONRAD, ARMIN
Publication of US20100021324A1 publication Critical patent/US20100021324A1/en
Abandoned legal-status Critical Current

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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
    • 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
    • F04D19/044—Holweck-type 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
    • F04D29/05—Shafts or bearings, or assemblies thereof, specially adapted for elastic fluid pumps
    • F04D29/056—Bearings
    • F04D29/057—Bearings hydrostatic; hydrodynamic

Definitions

  • the present invention relates to a vacuum pump having a shaft supported for rotation by two radial bearings, and a pumping system arranged on the shaft.
  • an object of the present invention is a vacuum pump capable to bridge the entire pressure region from atmospheric pressure and up to a high vacuum of 10 ⁇ 4 mbar and smaller.
  • a vacuum pump including spaced from each other, first and second dynamic gas bearings for supporting the shaft for rotation, and a pumping system arranged on the shaft between the first and second gas bearings and having two pumping sections which are so formed that a compressed gas from each of the two pumping sections is delivered in a direction of a gas bearing adjacent to a respective pumping section.
  • gas bearings permits to simplify the pump construction.
  • Gas bearings do not require any organic lubricant so that a lubricant circuit with a lubricant pump can be eliminated, and no contamination of a recipient and the pumped gas can occur.
  • Gas bearings are subjected to very little wear, which permits to achieve an extended service life of the pump, together with substantially reduced maintenance costs.
  • the construction of the pump is simplified due to a favorable gas guidance.
  • the favorable gas guidance is achieved by providing, in the pump system, pumping sections that pump gas in directions of respective gas bearings. Therefore, sealing means between the gas bearings and the pumping system can be eliminated.
  • a further advantage of the gas guidance according to the present invention consists in that the axial forces, which are produced in each pumping section by pressure difference between its gas inlet and gas outlet, are compensated. Therefore, overall, no axial forces acting on the shaft are produced by the pumping system. As a result of elimination of certain components and of the favorable gas guidance, a very compact vacuum pump is formed.
  • the gas delivery is further improved by arranging the respective pumping sections and the gas bearing adjacent thereto so that at least a portion of an operational gas of the gas bearing and gas expelled from the respective pumping section are combined at a point and flow together to a pump outlet. Such an arrangement further contributes to the compactness of the inventive vacuum pump.
  • At least one of the two pumping sections includes a Holweck pumping stage.
  • Holweck pumping stages have spiral-shaped channels. They can be formed in single manufacturing step together with structures necessary for gas bearings.
  • a Holweck pumping stage requires only few components, namely, channels formed in the shaft surface, and an opposite smooth cylindrical surface.
  • the vacuum pump is not only a low-cost pump but is also a very compact pump.
  • the Holweck stage includes, in addition to the channels formed in the shaft surface, oppositely directed channels provided on the stator. This increases the suction capacity, in particular in a pressure region adjacent to atmosphere. Therefore, less constructional space is needed for an increased suction capacity. This additionally contributes to the compactness of the inventive vacuum pump.
  • the suction capacity can be increased by providing, in a vacuum pump, a further pumping system.
  • the further pumping system also has a Holweck pumping stage. This one is formed by a hub connected with one end of the shaft, and a cylinder connected with the hub.
  • a back-up bearing is provided at the shaft ends.
  • the back-up bearings can be formed as slide bearings.
  • the back-up bearings permit to form a robust vacuum pump as they can withstand axial forces acting on the shaft.
  • the shaft material substantially consists of silicon carbide. This material combines the compatibility with the gas bearings with stability of the vacuum pump in different applications.
  • the rotor and the stator of the drive motor of the vacuum pump are so formed that they provide for an axial centering and, simultaneously, a rapid rotation of the shaft. This permits to eliminate the need for axial bearings, which further contributes to cost-effectiveness and compactness of the inventive vacuum pump.
  • FIG. 1 a cross-sectional view of vacuum pump according to the present invention.
  • FIG. 2 a cross-sectional view of a section of a vacuum pump according to a further embodiment of the present invention with a pumping system different from that of the vacuum pump shown in FIG. 1 .
  • a vacuum pump according to the present invention which is shown in FIG. 1 , has a housing 1 having a gas inlet 7 and a gas outlet 8 . Inside the housing 1 , there is arranged a cylinder 5 in which a shaft 2 is rotatably supported. At its opposite ends, the shaft is supported by two gas bearings 30 and 40 , respectively.
  • the first gas bearing 30 includes a gas inlet 31 , a shaft-side bearing structure 32 and a bearing gas outlet 34 .
  • the bearing structure 32 forms a bearing section 33 extending in the shaft axial direction.
  • the second gas bearing 40 includes a gas inlet 41 , a shaft-side bearing structure 42 and a bearing gas outlet 44 .
  • the bearing structure 42 forms a bearing section 43 extending in the shaft axial direction.
  • the bearing structures 32 and 42 include recesses formed in the surface of the shaft 2 .
  • each of the gas bearing outlets 34 and 44 is provided with two openings located, respectively, at opposite ends of the respective bearing section 32 , 42 .
  • only one gas inlet 31 , 41 is shown, respectively, as a rule a plurality of such inlets is provided in each bearing and which are distributed over the shaft circumference.
  • the cylinder 5 forms the stator of both gas bearings 30 and 40 , so that a gas film is formed between the shaft-side bearing structures 32 and 42 , respectively, and the cylinder 5 , with the shaft 2 being supported by the gas films.
  • the necessary bearing gas can be produced by a compressor 11 or, when the bearing load permits, can be taken directly from the atmosphere. In the latter case, the gas inlets 31 , 41 communicate directly with the atmosphere.
  • a compressed air from an on-site available, compressed air conduit can be used.
  • the shaft 2 has, at one of its ends, a shaft journal 29 on which permanent magnets 9 are mounted.
  • the permanent magnets 9 form a rotor of a drive motor and cooperate with electrical coils 10 to provide for a rapid rotation of the shaft 2 about its longitudinal axis.
  • the electrical coils 10 form a stator of the drive motor.
  • the motor rotor and the motor stator are so formed that they stabilize the shaft in the direction of its longitudinal axis. This is achieved, e.g., by action of the attraction forces of the stator iron core on the permanent magnets.
  • a back-up bearing is provided at the shaft end. In the embodiment shown in FIG.
  • the back-up bearing is formed as a slide bearing 14 that includes, on its shaft side, a spherical surface and, on its housing side, a tribologically suitable counter-surface.
  • permanent magnet rings can be provided in the axial direction, namely, a shaft-side bearing ring 26 and a stator-side bearing ring 27 .
  • the two bearing rings 26 , 27 form an axial permanent magnet bearing 25 .
  • Electronics 20 is arranged in an electronic housing 21 .
  • the electronics 20 is connected with the electrical coils 10 . If the compressor 11 is used for production of the bearing gas, the compressor control conductor 22 of the compressor 11 is connected with the pump electronics 20 that controls the operation of the compressor 11 , in particular its parameters such as actuation, deactuation, pressure level, and a feed amount.
  • the pumping system 6 is formed as a double-flow system and has a first pumping section 61 and a second pumping section 62 .
  • Each of the pumping sections 61 , 62 starts in a region of the gas inlet 7 , and the compressed gas flows in the direction of the gas bearing adjacent thereto, as shown by a straight arrows. From the bearing sections, at least a portion of the bearing gas is released in the direction of the pumping system.
  • the gas flows are combined at a location 13 between the first gas bearing 30 and the first pumping section 61 or at a location 13 ′ between the second gas bearing 40 and the second pumping section 62 and together are fed to the pump or housing outlet 8 .
  • This permits to obtain a very compact structure as a result of a simple gas flow circuit.
  • Both pumping sections achieve the same pressure ratios between their respective inlets and outlets.
  • Holweck structures are provided in the pumping sections.
  • spiral-shaped channels 63 which circumscribe the shaft 2 and cooperate with an inner surface of the cylinder 5 that acts as a pump stator. If the inner surface is smooth, a pump based on the working principle according to Holweck, is formed. This is not only favorable for the pressure region from the vacuum technical point of view but also allows advantageously to produce the shaft, together with the shaft-side bearing structures, in a single operational step.
  • channels 64 are provided on the inner surface of the cylinder 5 .
  • the channels 64 extend over a portion of the axial length of the pumping sections 61 and 62 , preferably, in the portion adjacent to the respective gas bearings 30 , 40 .
  • the channels 64 are to be formed so that they run opposite to the channels 63 on the shaft 2 , the pump rotor.
  • the stator-side channels increase the suction capacity.
  • the shaft 2 is formed as one piece at least in the region of the bearing sections 33 , 43 and the pumping sections 61 , 62 .
  • the cylinder 5 is likewise formed as one piece, at least in its region extending over the bearing sections 33 , 43 and the pumping section 61 , 62 .
  • valve 12 is advantageously provided in the gas inlet 7 of the vacuum pump and is connected by the valve control conductor 23 with the electronics 20 .
  • the control electronics 20 turns on the open condition of the safety valve 12 .
  • FIG. 2 shows a section of a further embodiment of the inventive vacuum pump designated as a box K.
  • the vacuum pump shown in FIG. 2 includes a further pumping system 100 located upstream of the pumping system 6 .
  • a Holweck stator 103 is provided in the housing of the vacuum pump.
  • the stator 103 has, in its cylindrical inner surface, a thread-shaped channel. The pitch sections of the channel are separated from each other by webs 105 .
  • a smooth cylinder 102 cooperates with the thread-shaped channel, whereby a pumping action is produced.
  • the cylinder 102 is connected with a hub 101 .
  • the cylinder 102 is formed of a light material, in particular of fiber-reinforced carbon.
  • the hub 101 is secured on an end of the shaft, so that the hub 101 and the cylinder 102 rotate with the same speed as the shaft 2 (see FIG. 1 ).
  • the first pumping system 6 is shown only partially, with only pumping section 62 being shown completely. Likewise, only the shaft-side bearing structure 42 of the second bearing 40 is shown.
  • a sealing section 106 is provided between the bearing structure 42 and the hub 101 .
  • the sealing section 106 is formed by arranging on the shaft a pumping structure, as in the first pumping system, and which cooperates with the cylinder 5 to produce a pressure difference.
  • the pumping structure of the sealing section is so formed that the pressure ratio between the side of the pumping structure adjacent to the bearing structure 42 and the side of the pumping structure adjacent to the hub 101 corresponds to the pressure ratio produced by the pumping section 62 .
  • the suction capacity of the pumping structure of the sealing section 106 can be noticeably smaller, as a smaller amount of bearing gas than that entering through the inlet 7 is used.
  • the further pumping system 100 can also be formed as a double-flow system.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Non-Positive Displacement Air Blowers (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
US12/460,738 2008-07-26 2009-07-22 Vacuum pump Abandoned US20100021324A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102008034948.8 2008-07-26
DE102008034948A DE102008034948A1 (de) 2008-07-26 2008-07-26 Vakuumpumpe

Publications (1)

Publication Number Publication Date
US20100021324A1 true US20100021324A1 (en) 2010-01-28

Family

ID=41221612

Family Applications (1)

Application Number Title Priority Date Filing Date
US12/460,738 Abandoned US20100021324A1 (en) 2008-07-26 2009-07-22 Vacuum pump

Country Status (4)

Country Link
US (1) US20100021324A1 (ja)
EP (1) EP2148094B1 (ja)
JP (1) JP5566636B2 (ja)
DE (1) DE102008034948A1 (ja)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130216404A1 (en) * 2012-02-22 2013-08-22 Bor-Haw Chang Bladeless fan structure
WO2014125238A1 (en) * 2013-02-15 2014-08-21 Edwards Limited Vacuum pump
CN104019043A (zh) * 2014-06-20 2014-09-03 李晨 鼠笼螺杆式复合分子泵

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101454083B1 (ko) * 2012-12-28 2014-10-21 삼성전기주식회사 전동 송풍기

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5017022A (en) * 1988-11-09 1991-05-21 Allied-Signal, Inc. High temperature bearing
US5273368A (en) * 1990-11-13 1993-12-28 Matsushita Electric Industrial Co., Ltd. Hydrodynamic gas bearing
US5793561A (en) * 1994-10-14 1998-08-11 Canon Kabushiki Kaisha Rotary drum assembly having dynamic-pressure generating mechanism between rotary shaft and bearing
US6224326B1 (en) * 1998-09-10 2001-05-01 Alcatel Method and apparatus for preventing deposits from forming in a turbomolecular pump having magnetic or gas bearings
US6368082B1 (en) * 1999-04-09 2002-04-09 Pfeiffer Vacuum Gmbh Vacuum pump with rotor supporting gas bearings
US6409477B1 (en) * 1999-07-05 2002-06-25 Pfeiffer Vacuum Gmbh Vacuum pump
US20070258836A1 (en) * 2006-05-04 2007-11-08 Pfeiffer Vacuum Gmbh Vacuum pump

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3150822A (en) * 1961-02-09 1964-09-29 Commissariat Energie Atomique Sealing and centering device for rotary shaft
JPS6255498A (ja) * 1985-09-05 1987-03-11 Asahi Glass Co Ltd セラミツクス製翼車
DE3705912A1 (de) * 1987-02-24 1988-09-01 Alcatel Hochvakuumtechnik Gmbh Hochvakuumpumpe mit einem glockenfoermigen rotor
JPS63255592A (ja) * 1987-04-13 1988-10-21 Ebara Corp タ−ボ分子ポンプ
JPH0198316U (ja) * 1987-12-21 1989-06-30
JPH0216396A (ja) * 1988-06-30 1990-01-19 Shimadzu Corp ターボ分子ポンプ
JPH0510289A (ja) * 1991-07-05 1993-01-19 Hitachi Koki Co Ltd 複合形ドライ真空ポンプ
DE19756837C2 (de) * 1997-12-19 1999-09-30 K Busch Gmbh Druck & Vakuum Dr Molekular- und Viskositätspumpe
JP3252792B2 (ja) * 1998-04-27 2002-02-04 株式会社島津製作所 ターボ形真空排気装置
JP2000249093A (ja) * 1999-02-26 2000-09-12 Daikin Ind Ltd 軸流式真空ポンプ

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5017022A (en) * 1988-11-09 1991-05-21 Allied-Signal, Inc. High temperature bearing
US5273368A (en) * 1990-11-13 1993-12-28 Matsushita Electric Industrial Co., Ltd. Hydrodynamic gas bearing
US5793561A (en) * 1994-10-14 1998-08-11 Canon Kabushiki Kaisha Rotary drum assembly having dynamic-pressure generating mechanism between rotary shaft and bearing
US6224326B1 (en) * 1998-09-10 2001-05-01 Alcatel Method and apparatus for preventing deposits from forming in a turbomolecular pump having magnetic or gas bearings
US6368082B1 (en) * 1999-04-09 2002-04-09 Pfeiffer Vacuum Gmbh Vacuum pump with rotor supporting gas bearings
US6409477B1 (en) * 1999-07-05 2002-06-25 Pfeiffer Vacuum Gmbh Vacuum pump
US20070258836A1 (en) * 2006-05-04 2007-11-08 Pfeiffer Vacuum Gmbh Vacuum pump

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130216404A1 (en) * 2012-02-22 2013-08-22 Bor-Haw Chang Bladeless fan structure
US9222478B2 (en) * 2012-02-22 2015-12-29 Asia Vital Components Co., Ltd. Bladeless fan structure
WO2014125238A1 (en) * 2013-02-15 2014-08-21 Edwards Limited Vacuum pump
CN104019043A (zh) * 2014-06-20 2014-09-03 李晨 鼠笼螺杆式复合分子泵

Also Published As

Publication number Publication date
JP5566636B2 (ja) 2014-08-06
EP2148094A2 (de) 2010-01-27
EP2148094A3 (de) 2016-04-13
DE102008034948A1 (de) 2010-01-28
EP2148094B1 (de) 2018-09-19
JP2010031857A (ja) 2010-02-12

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Legal Events

Date Code Title Description
AS Assignment

Owner name: PFEIFFER VACUUM GMBH, GERMANY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:CONRAD, ARMIN;REEL/FRAME:023031/0010

Effective date: 20090701

STCB Information on status: application discontinuation

Free format text: ABANDONED -- AFTER EXAMINER'S ANSWER OR BOARD OF APPEALS DECISION