EP0472751A1 - Rotor pour une pompe à vide avec des rotors à lobes - Google Patents

Rotor pour une pompe à vide avec des rotors à lobes Download PDF

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Publication number
EP0472751A1
EP0472751A1 EP90116357A EP90116357A EP0472751A1 EP 0472751 A1 EP0472751 A1 EP 0472751A1 EP 90116357 A EP90116357 A EP 90116357A EP 90116357 A EP90116357 A EP 90116357A EP 0472751 A1 EP0472751 A1 EP 0472751A1
Authority
EP
European Patent Office
Prior art keywords
rotor
profile
rotors
contour
vacuum 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.)
Granted
Application number
EP90116357A
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German (de)
English (en)
Other versions
EP0472751B1 (fr
Inventor
Ralf Steffens
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.)
Balzers und Leybold Deutschland Holding AG
Original Assignee
Leybold AG
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 Leybold AG filed Critical Leybold AG
Priority to DE59005764T priority Critical patent/DE59005764D1/de
Priority to EP90116357A priority patent/EP0472751B1/fr
Priority to JP3211810A priority patent/JPH04246284A/ja
Priority to US07/750,322 priority patent/US5152684A/en
Publication of EP0472751A1 publication Critical patent/EP0472751A1/fr
Application granted granted Critical
Publication of EP0472751B1 publication Critical patent/EP0472751B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • 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

Definitions

  • the invention relates to a rotor for a Roots vacuum pump with two identical rotors, each of which has an essentially eight-shaped profile contour consisting of four base profile sections and four head profile sections.
  • Roots vacuum pumps with rotors of this type have been widely used.
  • the rotational movement of the rotors synchronized by a gear following at the same speed occurs against one another and without contact to the housing wall.
  • the rotors are not subject to mechanical wear and can be operated at high speeds.
  • the gap width between the housing wall and the rotors and between the rotors themselves is a few tenths of a millimeter.
  • Figures 2, 3, 4 show that the profile contour of a rotor 1 is composed of four base profile sections 8, 9 and four head profile sections 11, 12.
  • the foot profile sections 8, 9 extend from the base of the foot (intersection of the contour with the short rotor axis 3) to the intersection of the contour with the pitch circle 5.
  • the four foot sections are in pairs (pairings 8, 8 and 9, 9) the same or mirror-symmetrical ( Pairings 8, 9).
  • the head profile sections each extend from the intersection of the contour with the long rotor axis 4 to the intersection with the pitch circle 5.
  • the four head profile sections are also identical in pairs (pairings 11, 11 and 12, 12) or mirror-symmetrical (pairings 11, 12).
  • the profile contours shown in FIGS. 1 and 2 to 4 correspond to the contour of rotors according to the prior art (involutes), which have been used many times in vacuum technology.
  • a centering angle ⁇ 0, for example, the slope of the tangent t o at the point of contact with the profile contour (FIG. 3) is 0.
  • FIG. 3 The for the rotor profile contour according to Figures 1a, 2 to 4 (involute) typical line of engagement is shown in FIG. 3 and designated egg. It has an eight-like shape with a center labeled C.
  • the line of engagement Ei is represented in a fixed or housing-fixed coordinate system x f , y f , the 0 point of which lies in the axis 2 of a rotor.
  • the coordinate system x f , y f is shown in FIG. 3.
  • a characteristic value for the properties of a Roots vacuum pump of the type concerned here is the area utilization factor u, defined as the ratio of the fourfold rotor scooping area F to the cross-sectional area Q of the scooping area 13.
  • the volume V delivered with each half rotation of the rotors is equal to the product of the rotor scooping area F and the Length I of the scoop chamber 13, so that the following applies to the theoretically conveyable amount of gas (pumping speed): where n is the speed of the pistons.
  • a large area utilization rate u leads to small and compact Roots vacuum pumps, which has an impact on the material and manufacturing costs and thus on the price of the pumps.
  • Roots vacuum pump Another characteristic value for the properties of a Roots vacuum pump is the volumetric efficiency ⁇ . It is defined as the ratio of the effectively extracted gas quantity Q eff to the theoretically extractable gas quantity Q th . Because of the gaps which are necessarily present in a tumbler vacuum pump of the type concerned here (contact-free movement of the rotors), backflows of the gases are inevitable and therefore Q eff is always less than Q th . The larger the, the better the compression behavior of a Roots vacuum pump. A relatively large one could be achieved, for example, by small gap widths at the "point of contact" on the one hand and between the rotors and the wall of the suction chamber on the other. Small gap widths result in a high temperature sensitivity of the pump. The reason for this is that the heat dissipation is limited by the pistons rotating in a vacuum. In the case of small gap widths, even a slight increase in the temperature of the rotors leads to a gap consumption and thus to the rotor starting.
  • Roots pump With regard to the optimization of the properties of a Roots pump, the largest possible values for ⁇ are desirable. At the same time, it must be taken into account that, in particular for the manufacture of the rotors, complex machining processes are required because of their special profile contours and because of the small gap widths. Because of these complex machining processes, the production of larger Roots machines with less favorable ⁇ and ⁇ values was often cheaper in the past than the production of smaller machines with better ⁇ and ⁇ values, but otherwise the same performance data.
  • CH-PS 389 817 also discloses a rotor profile contour with straight, parallel longitudinal sides for the foot profile (straight rotors). According to the information in the Swiss patent mentioned, this contour enables a relatively low final pressure to be achieved. However, a significant reduction in the area utilization rate is accepted, since the rotor head area F is larger in pumps with waisted pistons than in pumps with straight pistons (cf. surfaces 9 and 32 in FIGS. 4 b and 6 b of the CH-PS 389 817). Machines with rotor profile contours of the type proposed in CH-PS 389 817 therefore build relatively large, are correspondingly heavy and are therefore comparatively expensive.
  • the present invention has for its object to improve the profile contour of the rotors for a Roots vacuum pump.
  • this object is achieved by the characterizing features of the claims.
  • the contour of a foot profile section of a first rotor and the contour of a corresponding head profile section of a second rotor are obtained. Since these sections are identical to, or mirror-symmetrical to, the other base or head profile sections of the rotors due to the identity of the rotors, the entire profile contour of the rotors can be developed for a Roots machine.
  • Roots machine of this type it applies that it has a high area utilization factor ⁇ (62% and higher). As a result of this high degree of space utilization, a given small suction capacity results in a relatively small cross-sectional area Q and thus a compact and inexpensive construction.
  • a Roots vacuum pump with rotors of the type according to the invention has a relatively high volumetric efficiency ⁇ .
  • the reason for this is that the profile slope in the bottom of the waist (with small ⁇ values) is kept low. This results in favorable osculation values between the rotors themselves as well as between the rotors and the scoop wall.
  • the osculation is to be understood as the ratio of the radii of curvature of the surfaces forming the gaps. With favorable osculation values, the radii of curvature differ only slightly from one another. This practically lengthens the gaps between the pistons themselves and between the pistons and the wall of the pump chamber and thus a lower backflow rate. This extension of the column does not affect the temperature behavior of the pump.
  • the "contact point" on the line of engagement carries out a constant movement, ie a movement without regression or jumps (sudden skipping of larger profile contour sections), so that there are no dead volumes or other contaminated areas during the entire pass-through and thus volume inclusions or volume carryovers do not occur.
  • the rotor profile contour according to the invention has a uniform and continuous course, so that there are considerable manufacturing advantages. There are no abrupt changes in incline. A minimum (tool-related) radius of curvature is not undercut.
  • Figure 5 shows a pair of rotors with a profile contour according to the invention.
  • the area utilization rate u is 64%.
  • the slope at the bottom of the waist is small over a relatively wide range. It can therefore be seen that the cuddling of the rotors to one another and to the envelope is better than with the rotors according to the prior art.
  • Figure 6 shows the course of the curve ⁇ ( ⁇ ) depending on the central angle ⁇ from 0 to 45 °. Except for the start and end range (each about 5 °), ⁇ ( ⁇ ) is larger than ⁇ .
  • the straight line ⁇ ( ⁇ ) ⁇ is shown in dashed lines.
  • FIG. 7 shows engagement lines Ei, E2, E3 and E 4 , specifically in the fixed coordinate system x f , y f .
  • Half the waist width B and half the pitch circle diameter are shown.
  • the lines of engagement Ei, E2, E3 belong to the rotor profiles according to the prior art, namely
  • the outer, sine-like line of engagement E 4 characterizes a particularly advantageous embodiment of the rotor profile contour according to the invention, that is, it is expedient if the rotor profile contour according to the invention is selected such that its associated line of action E 4 has the largest possible amplitude and a sine-like shape.
  • the profile contour sections 8, 11 After the profile contour sections 8, 11 have been shaped in accordance with the present invention, the shape of the other contour sections 9, 12 and thus the complete rotor profile is fixed, since the other contour sections are identical to or mirror-symmetrical to the sections 8, 11.
  • the profile contour can be provided with an equidistant depending on the angle of rotation.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)
EP90116357A 1990-08-27 1990-08-27 Rotor pour une pompe à vide avec des rotors à lobes Expired - Lifetime EP0472751B1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
DE59005764T DE59005764D1 (de) 1990-08-27 1990-08-27 Rotor für eine Wälzkolbenvakuumpumpe.
EP90116357A EP0472751B1 (fr) 1990-08-27 1990-08-27 Rotor pour une pompe à vide avec des rotors à lobes
JP3211810A JPH04246284A (ja) 1990-08-27 1991-08-23 ルーツ形真空ポンプ用のロータ
US07/750,322 US5152684A (en) 1990-08-27 1991-08-27 Rotor profile for a roots vacuum pump

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP90116357A EP0472751B1 (fr) 1990-08-27 1990-08-27 Rotor pour une pompe à vide avec des rotors à lobes

Publications (2)

Publication Number Publication Date
EP0472751A1 true EP0472751A1 (fr) 1992-03-04
EP0472751B1 EP0472751B1 (fr) 1994-05-18

Family

ID=8204376

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90116357A Expired - Lifetime EP0472751B1 (fr) 1990-08-27 1990-08-27 Rotor pour une pompe à vide avec des rotors à lobes

Country Status (4)

Country Link
US (1) US5152684A (fr)
EP (1) EP0472751B1 (fr)
JP (1) JPH04246284A (fr)
DE (1) DE59005764D1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020134519A1 (fr) * 2018-12-28 2020-07-02 江南大学 Procédé servant à déterminer une région de conception raisonnable de profils de rotor de pompe roots et son utilisation
CN115076104A (zh) * 2022-06-24 2022-09-20 宁波爱发科真空技术有限公司 罗茨真空泵转子型线

Families Citing this family (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6095781A (en) * 1997-09-11 2000-08-01 Viking Pump, Inc. Timed element, high pressure, industrial rotary lobe pump
US5992230A (en) * 1997-11-15 1999-11-30 Hoffer Flow Controls, Inc. Dual rotor flow meter
US7527053B2 (en) 2003-08-04 2009-05-05 Cardinal Health 203, Inc. Method and apparatus for attenuating compressor noise
US8118024B2 (en) 2003-08-04 2012-02-21 Carefusion 203, Inc. Mechanical ventilation system utilizing bias valve
US8156937B2 (en) 2003-08-04 2012-04-17 Carefusion 203, Inc. Portable ventilator system
US20050112013A1 (en) * 2003-08-04 2005-05-26 Pulmonetic Systems, Inc. Method and apparatus for reducing noise in a roots-type blower
JP2007501074A (ja) 2003-08-04 2007-01-25 パルモネティック システムズ インコーポレイテッド 携帯型人工呼吸器システム
US7607437B2 (en) 2003-08-04 2009-10-27 Cardinal Health 203, Inc. Compressor control system and method for a portable ventilator
US7553143B2 (en) * 2004-04-19 2009-06-30 The Regents Of The University Of California Lobe pump system and method of manufacture
JP4677892B2 (ja) * 2005-12-07 2011-04-27 トヨタ自動車株式会社 ルーツ型ポンプおよび燃料電池システム
DE102006041633A1 (de) * 2006-09-05 2008-03-13 Herold & Co. Gmbh Pumpe
US7997885B2 (en) 2007-12-03 2011-08-16 Carefusion 303, Inc. Roots-type blower reduced acoustic signature method and apparatus
US8888711B2 (en) 2008-04-08 2014-11-18 Carefusion 203, Inc. Flow sensor
CN103334928B (zh) * 2013-06-09 2016-08-10 李锦上 节能摇摆活塞压缩机
DE102013110091B3 (de) * 2013-09-13 2015-02-12 Pfeiffer Vacuum Gmbh Wälzkolbenpumpe mit zwei Rotoren
JP2018168714A (ja) * 2017-03-29 2018-11-01 株式会社豊田自動織機 燃料電池用水素循環ポンプ
RU2730769C1 (ru) * 2020-02-19 2020-08-25 Акционерное общество "Вакууммаш" (АО "Вакууммаш") Двухроторная машина
CN114109824B (zh) * 2021-11-25 2023-08-15 江南大学 一种双螺杆转子型线综合性能判断及优化设计方法
JP2024113550A (ja) * 2023-02-09 2024-08-22 株式会社荏原製作所 真空ポンプ

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3089638A (en) * 1958-12-01 1963-05-14 Dresser Ind Impellers for fluid handling apparatus of the rotary positive displacement type
DE1503579A1 (de) * 1964-04-06 1970-03-19 Midland Ross Corp Verdichter fuer gasfoermige Medien
DD100312A1 (fr) * 1972-12-06 1973-09-12
US4938670A (en) * 1989-10-02 1990-07-03 Tocew Lee Rotary fluid machine

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE100312C (fr) *
GB953799A (en) * 1959-08-11 1964-04-02 Heraeus Gmbh W C Improvements in or relating to mechanical high vacuum pumps of the roots blower type
JP2761233B2 (ja) * 1989-02-17 1998-06-04 富士重工業株式会社 ルーツ型ブロワ

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3089638A (en) * 1958-12-01 1963-05-14 Dresser Ind Impellers for fluid handling apparatus of the rotary positive displacement type
DE1503579A1 (de) * 1964-04-06 1970-03-19 Midland Ross Corp Verdichter fuer gasfoermige Medien
DD100312A1 (fr) * 1972-12-06 1973-09-12
US4938670A (en) * 1989-10-02 1990-07-03 Tocew Lee Rotary fluid machine

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020134519A1 (fr) * 2018-12-28 2020-07-02 江南大学 Procédé servant à déterminer une région de conception raisonnable de profils de rotor de pompe roots et son utilisation
US11168682B2 (en) 2018-12-28 2021-11-09 Jiangnan University Method to determine the reasonable design area of rotor profile of roots pump and its application
CN115076104A (zh) * 2022-06-24 2022-09-20 宁波爱发科真空技术有限公司 罗茨真空泵转子型线
CN115076104B (zh) * 2022-06-24 2023-10-20 宁波爱发科真空技术有限公司 罗茨真空泵转子

Also Published As

Publication number Publication date
US5152684A (en) 1992-10-06
EP0472751B1 (fr) 1994-05-18
JPH04246284A (ja) 1992-09-02
DE59005764D1 (de) 1994-06-23

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