GB2420379A - Vacuum pump having a motor combined with an impeller - Google Patents
Vacuum pump having a motor combined with an impeller Download PDFInfo
- Publication number
- GB2420379A GB2420379A GB0425447A GB0425447A GB2420379A GB 2420379 A GB2420379 A GB 2420379A GB 0425447 A GB0425447 A GB 0425447A GB 0425447 A GB0425447 A GB 0425447A GB 2420379 A GB2420379 A GB 2420379A
- Authority
- GB
- United Kingdom
- Prior art keywords
- rotor
- stator
- cylindrical
- rotor element
- pump
- 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.)
- Withdrawn
Links
- 239000002131 composite material Substances 0.000 claims abstract description 18
- 239000011159 matrix material Substances 0.000 claims abstract description 9
- 230000003014 reinforcing effect Effects 0.000 claims abstract description 8
- 229920005989 resin Polymers 0.000 claims abstract description 7
- 239000011347 resin Substances 0.000 claims abstract description 7
- 239000007769 metal material Substances 0.000 claims abstract description 3
- 238000005086 pumping Methods 0.000 description 11
- 239000012634 fragment Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 239000004696 Poly ether ether ketone Substances 0.000 description 2
- 239000004411 aluminium Substances 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 229920002530 polyetherether ketone Polymers 0.000 description 2
- 230000000717 retained effect Effects 0.000 description 2
- 229920005992 thermoplastic resin Polymers 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- 229920000265 Polyparaphenylene Polymers 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- NDYCBWZIOSTTHS-UHFFFAOYSA-N cobalt samarium Chemical compound [Co].[Co].[Co].[Co].[Co].[Sm] NDYCBWZIOSTTHS-UHFFFAOYSA-N 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- -1 polyphenylene Polymers 0.000 description 1
- 230000001172 regenerating effect Effects 0.000 description 1
- 229920001187 thermosetting polymer Polymers 0.000 description 1
- 238000011144 upstream manufacturing Methods 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
- F04D25/00—Pumping installations or systems
- F04D25/02—Units comprising pumps and their driving means
- F04D25/06—Units comprising pumps and their driving means the pump being electrically driven
- F04D25/0606—Units comprising pumps and their driving means the pump being electrically driven the electric motor being specially adapted for integration in the pump
- F04D25/0613—Units comprising pumps and their driving means the pump being electrically driven the electric motor being specially adapted for integration in the pump the electric motor being of the inside-out type, i.e. the rotor is arranged radially outside a central stator
- F04D25/064—Details of the rotor
-
- 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
- F04D25/00—Pumping installations or systems
- F04D25/02—Units comprising pumps and their driving means
- F04D25/06—Units comprising pumps and their driving means the pump being electrically driven
- F04D25/0606—Units comprising pumps and their driving means the pump being electrically driven the electric motor being specially adapted for integration in the pump
- F04D25/0613—Units comprising pumps and their driving means the pump being electrically driven the electric motor being specially adapted for integration in the pump the electric motor being of the inside-out type, i.e. the rotor is arranged radially outside a central stator
- F04D25/0646—Details of the stator
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Non-Positive Displacement Air Blowers (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
A vacuum pump, such as a Holweck type pump, includes a pump rotor 18, a cylindrical rotor element 20, a stator 12 and a motor. The cylindrical rotor element 20 is mounted on the pump rotor 18, and the stator 12 includes a threaded cylindrical element 22 adjacent the cylindrical rotor element 20. The motor includes a rotor element 26 which is mounted on an inner surface of the cylindrical rotor element 20. The pump rotor 18 and stator 12 may be formed from composite materials, such as organic matrix materials, which may comprise a resin with reinforcing fibres and/or particulates. The pump rotor 18 and cylindrical rotor element 20 may be mounted co-axially on a shaft 10. The shaft 10 may be formed from a metallic material.
Description
VACUUM PUMP
This invention relates to a vacuum pump, and in particular to a vacuum pump comprising a molecular drag pumping mechanism.
A known type of molecular drag pumping mechanism is the Holweck pumping mechanism. A Holweck mechanism typically comprises one or more concentric cylindrical rotor elements mounted on a metallic rotor extending substantially orthogonal to a metallic drive shaft such that the longitudinal axes of the cylinders io are concentric with the longitudinal axis of the drive shaft. The cylinders are located within a stator having helical grooves of a progressively tapering section.
Traditionally, the rotor elements of a motor for driving the rotor are located on the drive shaft. For example, the rotor elements of the motor may be mounted on the is external surface of the drive shaft. However, the rotor elements of the motor subsequently require sheathing to protect the rotor elements, usually performed by mounting a metallic or composite shell over the rotor elements, and this tends to be a relatively complex procedure. Alternatively, the rotor elements may be located in a bore formed in the drive shaft. As the formation of a bore in the shaft can reduce the overall stiffness of the shaft, this requires the shaft to be formed from material having a relatively high specific stiffness and strength, increasing costs.
The present invention provides a vacuum pump comprising a rotor, a cylindrical rotor element formed from composite material and mounted on the rotor, a stator comprising a threaded cylindrical stator element adjacent the cylindrical rotor element, and a motor for driving the rotor, wherein a rotor element of the motor is mounted on the inner surface of the cylindrical rotor element.
The cylindrical rotor element is preferably formed from organic matrix composite material, such as carbon-fibre reinforced epoxy resin. Such material exhibits high specific stiftness and strength, and thus enables the rotor element to withstand -2- M04B162/ASB both the high levels of mechanical stress that occur during high-speed rotation of the rotor (typically greater than 330 m/s) and the additional load placed thereon by the motor rotor element.
In the preferred embodiment, the rotor is also formed from composite material, preferably one having an organic matrix, such as a resin with reinforcing particulates and/or fibres. The rotor is preferably mounted on a shaft co-axial with the cylindrical rotor element. The shaft may be formed from metallic material, such as aluminium or an alloy thereof, or from any other material of sufficient io specific stiffness and strength to withstand the stresses applied thereto during use.
By forming the rotor from composite material, the combination of rotor, cylindrical rotor element and motor rotor element will have a relatively low inertia during use.
A consequence of this is that in the result of a pump failure during use, any is fragments of this combination can be retained within the pump using a relatively low strength stator. In contrast, in the prior art where a metallic rotor is used, a metallic stator is required to retain any fragments of the rotor in the event of a failure. Therefore, in the preferred embodiment the stator is formed from composite material, preferably one having an organic matrix, such as a resin with reinforcing particulates and/or fibres.
Further magnetic elements may be mounted on the inner surface of the cylindrical rotor element as required. For example, elements of a passive magnetic bearing may be conveniently mounted on the cylindrical rotor element.
In addition to the molecular drag pumping mechanism defined by the rotor and stator elements of the pump, additional pumping stages may be provided as required. For example, one or more turbomolecular stage may be provided upstream from the molecular drag pumping mechanism, and/or one or more regenerative stages may be provided downstream from the molecular drag pumping mechanism.
-3- M04B162/ASB Preferred features of the present invention will now be described, by way of example only, with reference to the accompanying drawing which is a schematic cross-sectional view of part of a vacuum pump having a molecular drag pumping mechanism. An impeller of the pump comprises a shaft 10 formed from an aluminium alloy and retained within a stator 12 using bearings 14 for rotation relative thereto about the longitudinal axis 16 of the shaft 10. A rotor 18 is attached to one of the end of the shaft 10. In this example, the rotor 18 is in the form of a disc extending substantially orthogonal to the longitudinal axis 16 of the shaft 10. The rotor 18 is formed from an organic matrix composite material comprising a resin filled with reinforcing particles and/or fibres. For example, the rotor may be formed from a thermoplastic resin, such as PEEK (poly-ether- ether- ketone), reinforced with glass or carbon particles.
A cylindrical rotor element 20 of the impeller is attached to the rotor 18 such that the longitudinal axis of the cylindrical rotor element 20 is substantially co-axial with the longitudinal axis of the shaft 10. However, any number of such rotor elements may be attached to the rotor 18; where two or more rotor elements 20 are provided these are preferably arranged in a concentric manner on the rotor 18.
The cylindrical rotor element 20 is also formed from an organic matrix composite material. This material is preferably a thermosetting resin, such as epoxy, filled with reinforcing carbon fibres.
The stator 12 is provided with threaded elements 22 having helical grooves 24 adjacent the rotor element 20, each of a progressively tapering section, to define a two stage molecular drag pumping mechanism. Additional stages may be provided by including additional rotor elements 20 and corresponding threaded elements 22 of the stator 12.
A motor drives rotation of the impeller relative to the stator 12. As shown in the figure, one or more rotor elements 26 of the motor are mounted on the inner surface of the cylindrical rotor element 20 of the impeller, and a stator element 28 of the motor is mounted on the stator 12 of the pumping mechanism adjacent the -4- M04B162/ASB motor rotor element 26 and surrounded by coils 30. In this example, each motor rotor element 26 is preferably a permanent magnet formed from one of Samarium- Cobalt (SmCo5) or Iron-Nd-Boron (FeNdB) or Polymer-bonded-FeNdB, and thus requires a back iron element 32 to return and maintain the magnet flux across the poles of the motor rotor element 26. Alternatively, the motor rotor elements may have a Halbach magnetisation pattern so that a back iron element is not required.
The motor rotor elements 26 and, where required, back iron elements 32, may be enclosed within a shell 34, formed for example from aluminium, io In addition to defining the stator elements 22 of the pumping mechanism, the stator 12 serves to retain any fragments of the impeller generated as a result of pump failure. As the rotor 18 and cylindrical rotor element 20 are formed from composite material, the impeller will be relatively light, and so the kinetic energy stored in the impeller during rotation will be relatively low. As a result, the energy of any fragments generated by a pump failure will also be relatively low. In view of this, in the illustrated example the stator 12 may be conveniently formed from an organic matrix composite material, as this will have sufficient strength to retain any fragments of the impeller. This material is preferably a thermoplastic resin, such as PPS (polyphenylene sulphide), filled with reinforcing particles and/or fibres formed from glass or carbon. A relatively light, cheap pump can thus be provided.
Claims (9)
1. A vacuum pump comprising a rotor, a cylindrical rotor element formed from composite material and mounted on the rotor, a stator comprising a threaded cylindrical stator element adjacent the cylindrical rotor element, and a motor for driving the rotor, wherein a rotor element of the motor is mounted on the inner surface of the cylindrical rotor element.
2. A pump according to Claim 1, wherein the rotor is formed from composite material.
3. A pump according to Claim 2, wherein the composite material comprises an organic matrix.
4. A pump according to Claim 2 or Claim 3, wherein the composite material comprises a resin with reinforcing particulates and/or fibres.
5. A pump according to any of Claims 2 to 4, wherein the rotor is mounted on a shaft co-axial with the cylindrical rotor element.
6. A pump according to Claim 5, wherein the shaft is formed from metallic material.
7. A pump according to any of Claims 2 to 6, wherein the stator is formed from composite material.
8. A pump according to Claim 7, wherein the composite material of the stator comprises an organic matrix.
-6- M04B162/ASB
9. A pump according to Claim 7 or Claim 8, wherein the composite material of the stator comprises a resin with reinforcing particulates and/or fibres.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0425447A GB2420379A (en) | 2004-11-18 | 2004-11-18 | Vacuum pump having a motor combined with an impeller |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0425447A GB2420379A (en) | 2004-11-18 | 2004-11-18 | Vacuum pump having a motor combined with an impeller |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0425447D0 GB0425447D0 (en) | 2004-12-22 |
| GB2420379A true GB2420379A (en) | 2006-05-24 |
Family
ID=33548509
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0425447A Withdrawn GB2420379A (en) | 2004-11-18 | 2004-11-18 | Vacuum pump having a motor combined with an impeller |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2420379A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2295812A1 (en) * | 2009-07-30 | 2011-03-16 | Pfeiffer Vacuum Gmbh | Vacuum pump |
| WO2011092674A1 (en) * | 2010-02-01 | 2011-08-04 | Agilent Technologies Italia S.P.A. | High-vacuum pump |
| JP2013113300A (en) * | 2011-11-26 | 2013-06-10 | Pfeiffer Vacuum Gmbh | High-speed rotating rotor for vacuum pump |
| US20140294565A1 (en) * | 2011-11-30 | 2014-10-02 | Arisawa Mfg. Co., Ltd. | Vacuum pump |
| WO2015071143A1 (en) * | 2013-11-12 | 2015-05-21 | Oerlikon Leybold Vacuum Gmbh | Rotor device for a vacuum pump, and vacuum pump |
| EP2565463A3 (en) * | 2011-09-05 | 2015-10-14 | Pfeiffer Vacuum GmbH | Vacuum pump |
| EP4348055A1 (en) * | 2021-06-04 | 2024-04-10 | Edwards Limited | Holweck drag pump |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1459884A (en) * | 1973-09-29 | 1976-12-31 | Leybold Heraeus Verwaltung | Turbomolecular pump direct current power converter |
| EP0283287A2 (en) * | 1987-03-18 | 1988-09-21 | Seiko Seiki Kabushiki Kaisha | Pump |
| US5106273A (en) * | 1990-03-07 | 1992-04-21 | Alcatel Cit | Vacuum pump for producing a clean molecular vacuum |
| EP1408237A1 (en) * | 2002-10-11 | 2004-04-14 | Alcatel | Turbomolecular pump |
-
2004
- 2004-11-18 GB GB0425447A patent/GB2420379A/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1459884A (en) * | 1973-09-29 | 1976-12-31 | Leybold Heraeus Verwaltung | Turbomolecular pump direct current power converter |
| EP0283287A2 (en) * | 1987-03-18 | 1988-09-21 | Seiko Seiki Kabushiki Kaisha | Pump |
| US5106273A (en) * | 1990-03-07 | 1992-04-21 | Alcatel Cit | Vacuum pump for producing a clean molecular vacuum |
| EP1408237A1 (en) * | 2002-10-11 | 2004-04-14 | Alcatel | Turbomolecular pump |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2295812A1 (en) * | 2009-07-30 | 2011-03-16 | Pfeiffer Vacuum Gmbh | Vacuum pump |
| WO2011092674A1 (en) * | 2010-02-01 | 2011-08-04 | Agilent Technologies Italia S.P.A. | High-vacuum pump |
| CN102906427A (en) * | 2010-02-01 | 2013-01-30 | 安捷伦科技有限公司 | High vacuum pump |
| CN102906427B (en) * | 2010-02-01 | 2016-02-03 | 安捷伦科技有限公司 | High vacuum pump |
| US10968915B2 (en) | 2010-02-01 | 2021-04-06 | Agilent Technologies, Inc. | High-vacuum pump |
| EP2565463A3 (en) * | 2011-09-05 | 2015-10-14 | Pfeiffer Vacuum GmbH | Vacuum pump |
| JP2013113300A (en) * | 2011-11-26 | 2013-06-10 | Pfeiffer Vacuum Gmbh | High-speed rotating rotor for vacuum pump |
| EP2597313A3 (en) * | 2011-11-26 | 2014-11-12 | Pfeiffer Vacuum Gmbh | High speed rotor for a vacuum pump |
| US20140294565A1 (en) * | 2011-11-30 | 2014-10-02 | Arisawa Mfg. Co., Ltd. | Vacuum pump |
| US9835170B2 (en) * | 2011-11-30 | 2017-12-05 | Edwards Japan Limited | Vacuum pump with fiber-reinforced resin cylinder |
| WO2015071143A1 (en) * | 2013-11-12 | 2015-05-21 | Oerlikon Leybold Vacuum Gmbh | Rotor device for a vacuum pump, and vacuum pump |
| EP4348055A1 (en) * | 2021-06-04 | 2024-04-10 | Edwards Limited | Holweck drag pump |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0425447D0 (en) | 2004-12-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |