EP0198936B1 - Multistage vacuum pump - Google Patents

Multistage vacuum pump Download PDF

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Publication number
EP0198936B1
EP0198936B1 EP85104947A EP85104947A EP0198936B1 EP 0198936 B1 EP0198936 B1 EP 0198936B1 EP 85104947 A EP85104947 A EP 85104947A EP 85104947 A EP85104947 A EP 85104947A EP 0198936 B1 EP0198936 B1 EP 0198936B1
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EP
European Patent Office
Prior art keywords
vacuum pump
labyrinth
vacuum
split
rotor system
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.)
Expired
Application number
EP85104947A
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German (de)
French (fr)
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EP0198936A1 (en
Inventor
Hanns-Peter Dr. Berges
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Balzers und Leybold Deutschland Holding AG
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Leybold AG
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Filing date
Publication date
Application filed by Leybold AG filed Critical Leybold AG
Priority to EP85104947A priority Critical patent/EP0198936B1/en
Priority to DE8585104947T priority patent/DE3574274D1/en
Priority to JP9347486A priority patent/JPS61283781A/en
Publication of EP0198936A1 publication Critical patent/EP0198936A1/en
Application granted granted Critical
Publication of EP0198936B1 publication Critical patent/EP0198936B1/en
Expired legal-status Critical Current

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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
    • 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
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/30—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members
    • F04C18/34—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F04C18/08 or F04C18/22 and relative reciprocation between the co-operating members
    • F04C18/344—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F04C18/08 or F04C18/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the inner member
    • F04C18/3441—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F04C18/08 or F04C18/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the inner member the inner and outer member being in contact along one line or continuous surface substantially parallel to the axis of rotation
    • 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

Definitions

  • the invention relates to a multi-stage, fluid-sealed vacuum pump with a housing that has at least two housing rings, two front housing covers and at least one cutting disc to form scoops, and a rotor system that has at least two rotors and bearings arranged together on a shaft for the rotor system, the rotor system being held or supported in two bearings arranged on the end face.
  • a two- or multi-stage vacuum pump practically consists of two or more single-stage vacuum pumps, which are either arranged side by side (with axes of rotation parallel to each other) or one behind the other (with a common shaft or axis of rotation).
  • the present invention relates to a multi-stage rotary piston vacuum pump of the last-mentioned type.
  • the common shaft assigned to the rotors is held in the end faces of the housing in roller or slide bearings, while the bearing of the rotor system in the partition or cutting disc is usually designed as a slide bearing.
  • the cutting disc also has the function of sealing the scoops under various pressures as completely as possible from one another during operation.
  • Some technical problems are associated with the intermediate storage in the cutting disc, which are based initially on the fact that the intermediate storage is a third bearing for the rotor system and thus represents an over-determination. It is known to avoid the disadvantageous consequences of this overdetermination in that, in the course of the assembly of a multi-stage vacuum pump, the rotor system is first held in the bearing caps and then the cutting disc is adjusted. This assembly is complicated and time-consuming. Another disadvantage of previously known multi-stage vacuum pumps of this type is that three points of the vacuum pump have to be supplied with lubricants which meet high demands with regard to the lubricity.
  • the present invention has for its object to provide a multi-stage rotary piston vacuum pump of the type mentioned, in which the bearing, sealing and lubrication problems are significantly reduced.
  • this object is achieved in that the implementation of the rotor system through the cutting disk is designed as a contact-free gap and / or labyrinth seal known per se, that the spaces in which the bearings of the rotor system are located are provided by sealing rings and / or by gap or labyrinth seals are separated from the respective pumping chambers and that the vacuum pump sealant, which is guided in a circuit independent of the storage rooms, is used to supply the gap and labyrinth seals.
  • the measure of completely dispensing with intermediate storage initially has the advantage that overdetermination problems no longer exist.
  • sealant which has to be adapted to the process which takes place within the recipient to be evacuated.
  • sealants can be, for example, substances occurring in the process, such as dioctyl phthalate (DOP), which have no high-quality lubricating properties, but are sufficient to supply a gap or labyrinth seal.
  • DOP dioctyl phthalate
  • the storage of the rotor system in the end covers can be supplied independently with high-quality lubricants, for example greases.
  • the diameter of the fore-vacuum rotor is less than or equal to the diameter of the rotor-side part of the gap or labyrinth seal. A complete assembly ". Of the rotor outside the housing and thus a minimization of the concentricity errors is made possible.
  • the figure shows a two-stage vacuum pump 1 in rotary vane design with a forevacuum (VV) stage 2 and a high vacuum (HV) stage 3.
  • the housing of the vacuum pump 1 comprises the housing cover 4 on the VV side, which in this embodiment consists of the bearing ring 5 of the disk 6 and the end cover 7.
  • the end of the scooping space 9 towards the HV side is formed by the intermediate wall or separating disk 11 to which the HV housing ring 12 is connected on the HV side and forms the HV scooping space 13.
  • the bearing cover 14 forms the end of the HV side or the HV scoop space 13 to the outside.
  • the rotor system comprises the W rotor 15 and the HV rotor 16, which are arranged on a common shaft 17.
  • the shaft 17 is rotatably supported in the bearing caps 4 and 14 by means of the bearings 18 and 19.
  • On the HV side the shaft 17 is connected via the coupling 21 to a drive motor, not shown.
  • the bearing 18 on the VV side is located in the bearing ring 5.
  • the shaft 17 extends into the disk 6, in which a feed pump 22 for the sealant of the two-stage pump 1 shown is accommodated.
  • the feed pump 22 is separated from the bearing 18 of the shaft 17 by means of the radial seal 23 in the disk 6.
  • a two-stage rotary vane vacuum pump has been chosen as the exemplary embodiment.
  • the slot for a slide passing through the W rotor is shown in dashed lines and designated by 10.
  • the use of the invention is also possible with other types of two-stage vacuum pumps with rotors lying one behind the other on a shaft (for example gate valve pumps) or also with two-stage two-shaft pumps in which two rotors are arranged one behind the other on each shaft (root pump, Northey pump).
  • the rotor system is no longer supported in the cutting disc 11.
  • a labyrinth seal 25 is provided in the area of the cutting disc 11.
  • this comprises two grooves 26 and 27.
  • the gap width depends on the size of the parts, their materials and possible temperatures during operation in order to allow thermal expansion of the parts; the possible play of the bearings 18, 19 must also be taken into account.
  • the gap widths are on the order of a few hundredths of a millimeter.
  • the advantage of this solution is that not only a bearing but also a supply of high-quality lubricants can be dispensed with at this point.
  • the sealant of the pump which often does not have very good lubricating properties, is sufficient to seal the labyrinth or gap seal 25.
  • the bearings 18 and 19 can be supplied with a separate lubricant - preferably grease.
  • a separation of the storage rooms from the scooping rooms 9 and 13 is necessary for this. This separation can be realized by radial sealing rings 28, 29 and / or also by labyrinth or gap seals.
  • the storage space of the W-side bearing 18 is separated from the scooping space 9 by the radial sealing ring 28.
  • a combination consisting of the labyrinth seal 31 and the radial sealing ring 29 has been selected.
  • the exemplary embodiment shown has the feed pump for the sealant of the pump already mentioned in the cutting disc 6.
  • the pump sucks the sealant from the sump 32 through the channel 33 and presses it into the channel 34, with a pressure of greater than 1 bar.
  • the sealant is used in a manner known per se to supply the scoops 9 and 13 and then returns to the pump sump 32.
  • the existing labyrinth seals 25 and 31 are to be supplied with the sealant. This is done in relation to the labyrinth seal 25 with the aid of the bore 36, which starts from the channel 34 and opens out on the VV side of the labyrinth seal 25. As a result, a film is produced in the labyrinth seal 25, so that it is possible to seal the opening in the partition 11, which has no bearing function, between the HV and W stages.
  • the bore 37 is used, which leads from the channel 34 to the pressure-side end of the labyrinth seal 31.
  • the degassing channels 41 and 42 which on the HV side open into the labyrinth seals 25 and 31 - preferably at the level of the groove closest to the HV side.
  • the channels 41 and 42 connect these areas of the labyrinth seals 25 and 31 to the space 43, which in turn is connected to the suction side of the fore-vacuum stage 2, that is to say has an intermediate vacuum.
  • the degassing ensures that there is no inadmissible impairment of the final pressure of the HV stage.
  • the essential idea on which the invention is based is to dispense with an intermediate store in the area of the partition 11.
  • this dispensation presupposes that that the rotor system is mounted in both bearing caps 4 and 14.

Description

Die Erfindung bezieht sich auf eine mehrstufige, mit einem Fluid gedichtete Vakuumpumpe mit einem Gehäuse, das mindestens zwei Gehäuseringe, zwei stirnseitige Gehäusedeckel und mindestens eine Trennscheibe zur Bildung von Schöpfräumen aufweist, und einem Rotorsystem, das mindestens zwei gemeinsam auf einer Welle angeordnete Rotoren sowie Lagerungen für das Rotorsystem umfaßt, wobei das Rotorsystem in zwei stirnseitig angeordneten Lagern gehaltert bzw. gelagert ist.The invention relates to a multi-stage, fluid-sealed vacuum pump with a housing that has at least two housing rings, two front housing covers and at least one cutting disc to form scoops, and a rotor system that has at least two rotors and bearings arranged together on a shaft for the rotor system, the rotor system being held or supported in two bearings arranged on the end face.

Eine zwei- oder mehrstufige Vakuumpumpe besteht praktisch aus zwei oder mehreren einstufigen Vakuumpumpen, die entweder nebeneinander (mit zueinander parallelen Drehachsen) oder hintereinander (mit einer gemeinsamen Welle bzw. Drehachse) angeordnet sind. Auf eine mehrstufige Rotationskolbenvakuumpumpe der zuletzt genannten Gattung bezieht sich die vorliegende Erfindung.A two- or multi-stage vacuum pump practically consists of two or more single-stage vacuum pumps, which are either arranged side by side (with axes of rotation parallel to each other) or one behind the other (with a common shaft or axis of rotation). The present invention relates to a multi-stage rotary piston vacuum pump of the last-mentioned type.

Ublicherweise ist die den Rotoren zugeordnete, gemeinsame Welle in den Stirnseiten des Gehäuses in Wälz- oder Gleitlagern gehaltert, während die Lagerung des Rotorsystemes in der Trennwand oder Trennscheibe in der Regel als Gleitlager ausgebildet ist. Die Trennscheibe hat außerdem noch die Funktion, die während des Betriebs unter verschiedenen Drücken stehenden Schöpfräume möglichst vollständig gegeneinander abzudichten.Usually, the common shaft assigned to the rotors is held in the end faces of the housing in roller or slide bearings, while the bearing of the rotor system in the partition or cutting disc is usually designed as a slide bearing. The cutting disc also has the function of sealing the scoops under various pressures as completely as possible from one another during operation.

Mit dem Zwischenlager in der Trennscheibe sind einige technische Probleme verbunden, welche zunächst darauf beruhen, daß das Zwischenlager ein drittes Lager für das Rotorsystem ist und somit eine Überbestimmung darstellt. Es ist bekannt, die nachteiligen Folgen dieser Überbestimmung dadurch zu vermeiden, daß im Zuge der Montage einer mehrstufigen Vakuumpumpe das Rotorsystem zunächst in den Lagerdeckeln gehaltert wird und danach eine Justage der Trennscheibe erfolgt. Diese Montage ist kompliziert und aufwendig. Ein weiterer Nachteil vorbekannter mehrstufiger Vakuumpumpen dieser Art besteht darin, daß drei Stellen der Vakuumpumpe mit in Bezug auf die Schmierfähigkeit hohen Ansprüchen genügenden Schmierstoffen versorgt werden müssen.Some technical problems are associated with the intermediate storage in the cutting disc, which are based initially on the fact that the intermediate storage is a third bearing for the rotor system and thus represents an over-determination. It is known to avoid the disadvantageous consequences of this overdetermination in that, in the course of the assembly of a multi-stage vacuum pump, the rotor system is first held in the bearing caps and then the cutting disc is adjusted. This assembly is complicated and time-consuming. Another disadvantage of previously known multi-stage vacuum pumps of this type is that three points of the vacuum pump have to be supplied with lubricants which meet high demands with regard to the lubricity.

Um die Schwierigkeiten der Montage des Zwischenlagers zu reduzieren, ist es bekannt (DE-OS-3 129 232), die dem Rotorsystem gemeinsame Welle im Bereich des Zwischenlagers zu trennen und dort eine Kupplungsanordnung vorzusehen. An dieser Lösung ist nachteilig, daß praktisch zwei Lager im Bereich der Trennscheibe angeordnet werden müssen, so daß die axiale Ausdehnung der Trennscheibe und des bzw. der Zwischenlager relativ groß wird.In order to reduce the difficulties in assembling the intermediate bearing, it is known (DE-OS-3 129 232) to separate the shaft common to the rotor system in the region of the intermediate bearing and to provide a coupling arrangement there. This solution has the disadvantage that practically two bearings have to be arranged in the region of the cutting disc, so that the axial extent of the cutting disc and the intermediate bearing or bearings is relatively large.

Bei kleineren Vakuumpumpen (DE-OS-2 354 039) ist es bekannt, eine der beiden Stufen einer zweistufigen Vakuumpumpe fliegend zu lagern, so daß auf eine der beiden stirnseitigen Lagerungen verzichtet werden kann. Die Überbestimmungsprobleme sind bei dieser Lösung nicht mehr vorhanden; ein mit hochwertigen Schmierstoffen zu versorgendes Lager in der Zwischenwand ist jedoch immer noch vorhanden. Außerdem ist eine derartige Anordnung für größere Pumpen (oberhalb von 100 m3/h) nicht geeignet, da auf ein stirnseitiges Lager nur im Bereich der Hochvakuumstufe verzichtet werden kann. Bei größeren Vakuumpumpen ist aber gerade die Hochvakuumstufe größer und damit schwerer auszubilden als die Vorvakuumstufe, so daß insbesondere die Hochvakuumstufe eine stirnseitige Lagerung benötigt.In the case of smaller vacuum pumps (DE-OS-2 354 039) it is known to mount one of the two stages of a two-stage vacuum pump on the fly, so that one of the two end bearings can be dispensed with. The problems of overdetermination no longer exist with this solution; however, a bearing in the partition wall to be supplied with high-quality lubricants is still present. In addition, such an arrangement is not suitable for larger pumps (above 100 m 3 / h), since an end bearing can only be dispensed with in the area of the high vacuum stage. In the case of larger vacuum pumps, however, it is precisely the high vacuum stage which is larger and thus more difficult to design than the fore vacuum stage, so that the high vacuum stage in particular requires end-face mounting.

Der vorliegenden Erfindung liegt die Aufgabe zugrunde, eine mehrstufige Rotationskolbenvakuumpumpe der eingangs genannten Art zu schaffen, bei der die Lager-, Dicht- und Schmierprobleme erheblich reduziert sind.The present invention has for its object to provide a multi-stage rotary piston vacuum pump of the type mentioned, in which the bearing, sealing and lubrication problems are significantly reduced.

Erfindungsgemäß wird diese Aufgabe dadurch gelöst, daß die Durchführung des Rotorsystems durch die Trennscheibe als an sich bekannte berührungsfreie Spalt- und/oder Labyrinthdichtung ausgebildet ist, daß die Räume, in denen sich die Lagerungen des Rotorsystems befinden, durch Dichtringe und/oder durch Spalt-oder Labyrinthdichtungen von den jeweiligen Schöpfräumen getrennt sind und daß zur Versorgung der Spalt- und Labyrinthdichtungen das, in einem von den Lagerräumen unabhängigen Kreislauf geführte, Dichtmittel der Vakuumpumpe dient. Die Maßnahme des völligen Verzichts einer Zwischenlagerung hat zunächst den Vorteil, daß Überbestimmungsprobleme nicht mehr vorhanden sind. Weiterhin ist es nicht erforderlich, die Dichtung im Bereich der Trennwand mit hochwertigen Schmierstoffen zu versorgen, das heißt, es besteht die Möglichkeit, die Schmierung der stirnseitigen Lagerungen von der Versorgung der Dichtung in der Trennscheibe mit einem Dichtmittel zu separieren. Dieser Vorteil wird besonders bedeutsam, wenn die Vakuumpumpe mit einem Dichtmittel betrieben werden muß, welches dem Prozeß, der innerhalb des zu evakuierenden Rezipienten abläuft, angepaßt werden muß. Solche Dichtmittel können zum Beispiel im Prozeß anfallende Substanzen, wie Dioctylphtalat (DOP) sein, die keine hochwertigen Schmiereigenschaften haben, zur Versorgung einer Spalt- oder Labyrinthdichtung aber ausreichen. Die Lagerung des Rotorsystemes in den Stirndeckeln können davon unabhängig mit hochwertigen Schmierstoffen, zum Beispiel Schmierfetten, versorgt werden. Zweckmäßig ist es, wenn der Durchmesser des Vorvakuum-Rotors kleiner oder gleich dem Durchmesser des rotorseitigen Teils der Spalt- oder Labyrinthdichtung ist. Eine vollständige Montage". des Rotors außerhalb des Gehäuses und damit eine Minimierung der Rundlauffehler wird dadurch ermöglicht.According to the invention, this object is achieved in that the implementation of the rotor system through the cutting disk is designed as a contact-free gap and / or labyrinth seal known per se, that the spaces in which the bearings of the rotor system are located are provided by sealing rings and / or by gap or labyrinth seals are separated from the respective pumping chambers and that the vacuum pump sealant, which is guided in a circuit independent of the storage rooms, is used to supply the gap and labyrinth seals. The measure of completely dispensing with intermediate storage initially has the advantage that overdetermination problems no longer exist. Furthermore, it is not necessary to supply the seal in the area of the partition with high-quality lubricants, which means that there is the possibility of separating the lubrication of the end bearings from the supply of the seal in the separating disc with a sealant. This advantage becomes particularly significant if the vacuum pump has to be operated with a sealant which has to be adapted to the process which takes place within the recipient to be evacuated. Such sealants can be, for example, substances occurring in the process, such as dioctyl phthalate (DOP), which have no high-quality lubricating properties, but are sufficient to supply a gap or labyrinth seal. The storage of the rotor system in the end covers can be supplied independently with high-quality lubricants, for example greases. It is expedient if the diameter of the fore-vacuum rotor is less than or equal to the diameter of the rotor-side part of the gap or labyrinth seal. A complete assembly ". Of the rotor outside the housing and thus a minimization of the concentricity errors is made possible.

Bei zweistufigen Schraubenkompressoren, wie sie in· der US-A-3 265 292 und den DE-A's-1 628 395 sowie 1 811 285 offenbart sind, ist es zwar an sich bekannt, zwischen den Förderräumen der beiden Stufen Labyrinthdichtungen vorzusehen; die Trennung der Dichtmittelversorgung der Labyrinthdichtungen von der Schmiermittelversorgung der Lagerungen in den stirnseitigen Gehäusedeckeln ist jedoch in diesen sich nicht auf Vakuumpumpen beziehenden Druckschriften nicht offenbart.In the case of two-stage screw compressors, as are disclosed in US Pat. Nos. 3,265,292 and DE-A-1,628,395 and 1,811,285, it is known per se to provide labyrinth seals between the conveying spaces of the two stages; the separation of the sealant supply However, labyrinth seals from the lubricant supply to the bearings in the front housing covers are not disclosed in these publications, which do not relate to vacuum pumps.

Weitere Vorteile und Einzelheiten der Erfindung sollen anhand eines in der Figur dargestellten Ausführungsbeispieles erläutert werden.Further advantages and details of the invention will be explained with reference to an embodiment shown in the figure.

Die Figur zeigt eine zweistufige Vakuumpumpe 1 in Drehschieberbauart mit einer Vorvakuum(VV)-Stufe 2 und einer Hochvakuum(HV)-Stufe 3. Das Gehäuse der Vakuumpumpe 1 umfaßt den VVseitigen Gehäusedeckel 4, der bei diesem Ausführungsbeispiel aus dem Lagerring 5 der Scheibe 6 und dem Abschlußdeckel 7 besteht. An den W-Lagerdeckel 4 schließt sich der W-Gehäusering 8 an, der den Schöpfraum 9 bildet. Den Abschluß des Schöpfraumes 9 zur HV-Seite hin bildet die Zwischenwand oder Trennscheibe 11 an die sich HV-seitig der HV-Gehäusering 12 anschließt und den HV-Schöpfraum 13 bildet. Den Abschluß der HV-Seite bzw. des HV-Schöpfraumes 13 nach außen bildet der Lagerdeckel 14.The figure shows a two-stage vacuum pump 1 in rotary vane design with a forevacuum (VV) stage 2 and a high vacuum (HV) stage 3. The housing of the vacuum pump 1 comprises the housing cover 4 on the VV side, which in this embodiment consists of the bearing ring 5 of the disk 6 and the end cover 7. The W housing ring 8, which forms the scooping chamber 9, adjoins the W bearing cover 4. The end of the scooping space 9 towards the HV side is formed by the intermediate wall or separating disk 11 to which the HV housing ring 12 is connected on the HV side and forms the HV scooping space 13. The bearing cover 14 forms the end of the HV side or the HV scoop space 13 to the outside.

Das Rotorsystem umfaßt den W-Rotor 15 und den HV-Rotor 16, die auf einer gemeinsamen Welle 17 angeordnet sind. Die Welle 17 ist in den Lagerdeckeln 4 und 14 mittels der Lagerungen 18 und 19 drehbar gehaltert. Auf der HV-Seite ist die Welle 17 über die Kupplung 21 mit einem nicht dargestellten Antriebsmotor verbunden. Die Lagerung 18 auf der VV-Seite befindet sich im Lagerring 5. Die Welle 17 erstreckt sich noch bis in die Scheibe 6, in der eine Förderpumpe 22 für das Dichtmittel der dargestellten zweistufigen Pumpe 1 untergebracht sind. Mittels der Radialdichtung 23 in der Scheibe 6 ist die Förderpumpe 22 von der Lagerung 18 der Welle 17 getrennt.The rotor system comprises the W rotor 15 and the HV rotor 16, which are arranged on a common shaft 17. The shaft 17 is rotatably supported in the bearing caps 4 and 14 by means of the bearings 18 and 19. On the HV side, the shaft 17 is connected via the coupling 21 to a drive motor, not shown. The bearing 18 on the VV side is located in the bearing ring 5. The shaft 17 extends into the disk 6, in which a feed pump 22 for the sealant of the two-stage pump 1 shown is accommodated. The feed pump 22 is separated from the bearing 18 of the shaft 17 by means of the radial seal 23 in the disk 6.

Als Ausführungsbeispiel ist eine zweistufige Drehschiebervakuumpumpe gewählt worden. Der den W-Rotor durchsetzende Schlitz für einen Schieber ist gestrichelt dargestellt und mit 10 bezeichnet. Der Einsatz der Erfindung ist jedoch auch bei anderen Typen von zweistufigen Vakuumpumpen mit auf einer Welle hintereinanderliegenden Rotoren (zum Beispiel Sperrschieberpumpen) oder auch bei zweistufigen Zweiwellenpumpen, bei denen auf jeder Welle zwei Rotoren hintereinander angeordnet sind (Rootspumpe, Northey-Pumpe) erfolgen.A two-stage rotary vane vacuum pump has been chosen as the exemplary embodiment. The slot for a slide passing through the W rotor is shown in dashed lines and designated by 10. However, the use of the invention is also possible with other types of two-stage vacuum pumps with rotors lying one behind the other on a shaft (for example gate valve pumps) or also with two-stage two-shaft pumps in which two rotors are arranged one behind the other on each shaft (root pump, Northey pump).

Entsprechend der erfindungsgemäßen Idee ist das Rotorsystem in der Trennscheibe 11 nicht mehr gelagert. Da jedoch eine Trennung der Schöpfräume 9 und 13 für die Funktion der Vakuumpumpe wichtig ist, ist im Bereich der Trennscheibe 11 eine Labyrinthdichtung 25 vorgesehen. Beim dargestellten Ausführungsbeispiel umfaßt diese zwei Nuten 26 und 27. Mehrere Nuten oder auch eine einfache Spaltdichtung sind möglich. Die Spaltweite ist abhängig von der Größe der Teile, deren Werkstoffe und mögliche Temperaturen während des Betriebs, um Wärmedehnungen der Teile zuzulassen; ferner muß das mögliche Spiel der Lager 18, 19 berücksichtigt werden. Es ergeben sich Spaltweiten in der Größenordnung von einigen Hundertstel Millimeter.According to the idea of the invention, the rotor system is no longer supported in the cutting disc 11. However, since a separation of the scoops 9 and 13 is important for the function of the vacuum pump, a labyrinth seal 25 is provided in the area of the cutting disc 11. In the illustrated embodiment, this comprises two grooves 26 and 27. Several grooves or a simple gap seal are possible. The gap width depends on the size of the parts, their materials and possible temperatures during operation in order to allow thermal expansion of the parts; the possible play of the bearings 18, 19 must also be taken into account. The gap widths are on the order of a few hundredths of a millimeter.

Der Vorteil dieser Lösung besteht darin, daß an dieser Stelle nicht nur auf ein Lager, sondern auch auf eine Versorgung dieses Lagers mit hochwertigen Schmierstoffen verzichtet werden kann. Das Dichtungsmittel der Pumpe, das häufig nicht sehr gute Schmiereigenschaften hat, reicht aus, um die Labyrinth- oder Spaltdichtung 25 abzudichten.The advantage of this solution is that not only a bearing but also a supply of high-quality lubricants can be dispensed with at this point. The sealant of the pump, which often does not have very good lubricating properties, is sufficient to seal the labyrinth or gap seal 25.

Die Lagerungen 18 und 19 können mit einem separaten Schmiermittel - vorzugsweise Schmierfett - versorgt sein. Eine Trennung der Lagerräume von den Schöpfräumen 9 und 13 ist dazu erforderlich. Diese Trennung kann durch Radialdichtringe 28, 29 und/oder auch durch Labyrinth- oder Spaltdichtungen verwirklicht werden. Beim dargestellten Ausführungsbeispiel ist der Lagerraum des W-seitigen Lagers 18 durch den Radialdichtring 28 vom Schöpfraum 9 getrennt. Hochvakuumseitig ist eine Kombination, bestehend aus der Labyrinthdichtung 31 und dem Radialdichtring 29, gewählt worden. Das dargestellte Ausführungsbeispiel weist in der Trennscheibe 6 die bereits erwähnte Förderpumpe für das Dichtmittel der Pumpe auf. Die Pumpe saugt das Dichtmittel aus dem Sumpf 32 durch den Kanal 33 und drückt es in den Kanal 34, und zwar mit einem Druck von größer 1 bar. Das Dichtmittel dient in an sich bekannter Weise der Versorgung der Schöpfräume 9 und 13 und gelangt danach in den Pumpensumpf 32 zurück.The bearings 18 and 19 can be supplied with a separate lubricant - preferably grease. A separation of the storage rooms from the scooping rooms 9 and 13 is necessary for this. This separation can be realized by radial sealing rings 28, 29 and / or also by labyrinth or gap seals. In the illustrated embodiment, the storage space of the W-side bearing 18 is separated from the scooping space 9 by the radial sealing ring 28. On the high vacuum side, a combination consisting of the labyrinth seal 31 and the radial sealing ring 29 has been selected. The exemplary embodiment shown has the feed pump for the sealant of the pump already mentioned in the cutting disc 6. The pump sucks the sealant from the sump 32 through the channel 33 and presses it into the channel 34, with a pressure of greater than 1 bar. The sealant is used in a manner known per se to supply the scoops 9 and 13 and then returns to the pump sump 32.

Zusätzlich sind bei der erfindungsgemäß ausgebildeten zweistufigen Pumpe die vorhandenen Labyrinthdichtungen 25 und 31 mit dem Dichtmittel zu versorgen. Dies geschieht in bezug auf die Labyrinthdichtung 25 mit Hilfe der Bohrung 36, die vom Kanal 34 ausgeht und auf der VV-Seite der Labyrinthdichtung 25 mündet. Dadurch wird in der Labyrinthdichtung 25 ein Film erzeugt, so daß es möglich ist, die Durchbrechung in der Trennwand 11, welche keine Lagerfunktion hat, zwischen HV und W-Stufe abzudichten. Zur Versorgung der Labyrinthdichtung 31 dient die Bohrung 37 die von dem Kanal 34 zum druckseitigen Ende der Labyrinthdichtung 31 führt.In addition, in the two-stage pump designed according to the invention, the existing labyrinth seals 25 and 31 are to be supplied with the sealant. This is done in relation to the labyrinth seal 25 with the aid of the bore 36, which starts from the channel 34 and opens out on the VV side of the labyrinth seal 25. As a result, a film is produced in the labyrinth seal 25, so that it is possible to seal the opening in the partition 11, which has no bearing function, between the HV and W stages. To supply the labyrinth seal 31, the bore 37 is used, which leads from the channel 34 to the pressure-side end of the labyrinth seal 31.

Weiterhin ist es zweckmäßig, den die Labyrinth-oder Spaltdichtungen 25, 31 von der VV- bzw. Druckseite in Richtung HV-Stufe durchströmenden Dichtmittelfilm vor dem Eintritt in den Schöpfraum 13 der HV-Stufe zu entgasen. Das geschieht durch die Entgasungskanäle 41 und 42, die HV-seitig in die Labyrinthdichtungen 25 und 31 - vorzugsweise in Höhe der der HV-Seite am nächsten gelegenen Nut - münden. Die Kanäle 41 und 42 stellen eine Verbindung dieser Bereiche der Labyrinthdichtungen 25 und 31 mit dem Raum 43 her, der seinerseits mit der Saugseite der Vorvakuumstufe 2 in Verbindung steht, also ein Zwischenvakuum aufweist. Die Entgasung sorgt dafür, daß keine unzulässige Beeinträchtigung des erreichten Enddruckes der HV-Stufe eintritt.Furthermore, it is expedient to degas the sealant film flowing through the labyrinth or gap seals 25, 31 from the VV or pressure side in the direction of the HV stage before it enters the scooping chamber 13 of the HV stage. This is done through the degassing channels 41 and 42, which on the HV side open into the labyrinth seals 25 and 31 - preferably at the level of the groove closest to the HV side. The channels 41 and 42 connect these areas of the labyrinth seals 25 and 31 to the space 43, which in turn is connected to the suction side of the fore-vacuum stage 2, that is to say has an intermediate vacuum. The degassing ensures that there is no inadmissible impairment of the final pressure of the HV stage.

Die wesentliche, der Erfindung zugrunde liegende Idee besteht in dem Verzicht auf ein Zwischenlager im Bereich der Trennwand 11. Bei größeren Pumpen setzt dieser Verzicht voraus, daß das Rotorsystem in beiden Lagerdeckeln 4 und 14 gelagert ist. Bei kleineren zweistufigen Vakuumpumpen besteht die Möglichkeit, das gesamte Rotorsystem einseitig und damit fliegend zu lagern, so daß ebenfalls auf eine Zwischenlagerung im Bereich der Trennwand 11 verzichtet werden kann.The essential idea on which the invention is based is to dispense with an intermediate store in the area of the partition 11. In the case of larger pumps, this dispensation presupposes that that the rotor system is mounted in both bearing caps 4 and 14. In the case of smaller two-stage vacuum pumps, it is possible to mount the entire rotor system on one side and thus on the fly, so that intermediate storage in the region of the partition 11 can also be dispensed with.

Claims (5)

1. A multi-stage, fluid-sealed vacuum pump, having a housing and a separation plate (11) to form two drawing chambers as well as a rotor system comprising two rotors mounted on a common shaft and bearings for the rotor system, in which the rotor system is held in two front-side bearings (18, 19), characterised in that the ducting of the rotor system through the separation plate (11) is constructed as a per se known contactless split- and/or labyrinth packing (25), that the chambers in which the bearings (18, 19) of the rotor system are located are separated by means of packing rings (28, 29) and/or split- or labyrinth packings (31) from the associated drawing chambers (9, 13) and that the feed of the split- or labyrinth packings is provided by the sealing agent of the vacuum pump which is circulated in a cycle independent of the bearing frames.
2. A vacuum pump according to claim 1, characterised in that it is equipped with a sealant pump (22), by means of which the sealing agent of the vacuum pump is circulated in a cycle and that a delivery-side conduit (34) communicates with the fore-vacuum side of the labyrinth packing (25) through a bore (36).
3. A vacuum pump according to claim 2, characterised in that the labyrinth- or split packings serving to separate the bearing frames in the bearing caps (4 or 14) communicate on the pressure side with the delivery-side conduit (34) of the sealant circuit.
4. A vacuum pump according to any one of the preceding claims, characterised in that into the high-vacuum side part of the split- or labyrinth packings (25, 31) there opens a bore (41, 42) the other side of which communicates with a chamber (43) which in turn communicates with the intake side of the fore-vacuum stage (2).
5. A vacuum pump according to claims 1, 2 or 3, characterised in that the diameter of the fore-vacuum rotor (15) is smaller or equal to the diameter of the rotor-side part of the split- or labyrinth packing (25).
EP85104947A 1985-04-24 1985-04-24 Multistage vacuum pump Expired EP0198936B1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP85104947A EP0198936B1 (en) 1985-04-24 1985-04-24 Multistage vacuum pump
DE8585104947T DE3574274D1 (en) 1985-04-24 1985-04-24 Multistage vacuum pump
JP9347486A JPS61283781A (en) 1985-04-24 1986-04-24 Multistage type vacuum pump

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP85104947A EP0198936B1 (en) 1985-04-24 1985-04-24 Multistage vacuum pump

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EP0198936A1 EP0198936A1 (en) 1986-10-29
EP0198936B1 true EP0198936B1 (en) 1989-11-15

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EP (1) EP0198936B1 (en)
JP (1) JPS61283781A (en)
DE (1) DE3574274D1 (en)

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DE102012217071A1 (en) * 2012-09-21 2014-03-27 Robert Bosch Gmbh pump assembly
GB2535187A (en) * 2015-02-11 2016-08-17 Flybrid Automotive Ltd Vacuum pump system
GB2535794B (en) * 2015-02-27 2018-07-18 Flybrid Automotive Ltd Vacuum management system
CN109026707A (en) * 2018-08-22 2018-12-18 中北大学 The combination pump that claw pumps are combined with slide valve pump

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Publication number Priority date Publication date Assignee Title
CN102656368A (en) * 2009-11-11 2012-09-05 爱德华兹有限公司 Corrosion resistant shaft sealing for a vacuum pump
CN102656368B (en) * 2009-11-11 2015-12-09 爱德华兹有限公司 For the anticorrosive shaft sealing of vacuum pump

Also Published As

Publication number Publication date
EP0198936A1 (en) 1986-10-29
DE3574274D1 (en) 1989-12-21
JPS61283781A (en) 1986-12-13

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