EP0365695B1 - Positive displacement twin-shaft vacuum pump - Google Patents

Positive displacement twin-shaft vacuum pump Download PDF

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Publication number
EP0365695B1
EP0365695B1 EP88117651A EP88117651A EP0365695B1 EP 0365695 B1 EP0365695 B1 EP 0365695B1 EP 88117651 A EP88117651 A EP 88117651A EP 88117651 A EP88117651 A EP 88117651A EP 0365695 B1 EP0365695 B1 EP 0365695B1
Authority
EP
European Patent Office
Prior art keywords
pump according
rotors
vacuum pump
pump
suction chamber
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 - Lifetime
Application number
EP88117651A
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German (de)
French (fr)
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EP0365695A1 (en
Inventor
Hanns-Peter Dr. Berges
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 DE8888117651T priority Critical patent/DE3876243D1/en
Priority to EP88117651A priority patent/EP0365695B1/en
Priority to JP1275119A priority patent/JPH02153292A/en
Priority to US07/481,853 priority patent/US5046934A/en
Publication of EP0365695A1 publication Critical patent/EP0365695A1/en
Application granted granted Critical
Publication of EP0365695B1 publication Critical patent/EP0365695B1/en
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
    • F04C18/123—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 or approximately radially from the rotor body extending tooth-like elements, co-operating with recesses in the other rotor, e.g. one tooth
    • 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
    • F04C13/00—Adaptations of machines or pumps for special use, e.g. for extremely high pressures
    • F04C13/005—Removing contaminants, deposits or scale from the pump; Cleaning
    • 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
    • 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
    • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
    • F04C29/0007—Injection of a fluid in the working chamber for sealing, cooling and lubricating
    • 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
    • F04C2220/00—Application
    • F04C2220/10—Vacuum
    • F04C2220/12—Dry running
    • 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
    • F04C2280/00—Arrangements for preventing or removing deposits or corrosion
    • F04C2280/02—Preventing solid deposits in pumps, e.g. in vacuum pumps with chemical vapour deposition [CVD] processes

Definitions

  • the invention relates to a twin-shaft vacuum pump with a pair of claw rotors rotating in the suction chamber, which together with the suction chamber wall forms a suction side and a pressure side.
  • a twin-shaft vacuum pump of this type is known from EP-A-0 290 662.
  • the rotors are each equipped with a claw (tooth) and a recess and perform their rotary motion in the scooping chamber in a meshing and contact-free manner.
  • the respective cutouts control the inlet and outlet openings located in the side plates of the scoop chamber.
  • twin-shaft vacuum pumps of the type described are therefore often used for evacuating vacuum chambers in which etching, coating or other vacuum treatment or manufacturing processes are carried out. In such operations there is a risk that solids get into the pump, and although also indirectly, that is to say that solid particles only form during the compression of the gases, that is to say during the passage of the gases to be discharged through the vacuum pump. Examples include the formation of aluminum chloride in aluminum etching, ammonium chloride in coating processes, etc.
  • Solid particles that get directly or indirectly into the vacuum pump are deposited in the scooping chamber, including on the peripheral surfaces of the rotors, where they initially narrow the gap between the rotors. Further deposits cause the rotors to touch, which causes the solid particles to roll onto the rotor surfaces. If the deposits continue to increase, the rolled-on layer is thickened, so that a force is produced which pushes the rotors and thus the rotor shafts apart. This leads to bearing damage and thus to the failure of the pump, particularly if the rolled layer continues to grow.
  • the present invention has for its object to prevent in a twin-shaft vacuum pump of the type mentioned that solid particles entering the vacuum pump accumulate in the scoop.
  • this object is achieved in that a purge gas line opens on the pressure side into the scoop. If a flushing gas is supplied via this flushing gas line during operation of the pump, gas vortices arising in the scooping chamber prevent the deposition of solid particles entering the scooping chamber.
  • the amount of purge gas supplied does not have to be very high, since otherwise the final pressure of the pump would be unnecessarily deteriorated. It is particularly advantageous if the purge gas at high speed, for. B. is supplied via a nozzle. The solid particles which are kept in suspension as a result of the eddies which are produced can then be conveyed to the next pump stage or to the pump outlet.
  • the purge gas line is expediently located in the immediate vicinity of the gap seal of the two rotors. As a result, the particularly endangered peripheral surfaces of the two rotors are kept free of deposits.
  • the exemplary embodiment shown in FIG. 1 is a three-stage vacuum pump 1 with two shafts 2 and 3 and three pairs of rotors 4, 5 or 6, 7 or 8, 9.
  • the axial length of the rotors decreases from the suction side to the pressure side .
  • the rotary pistons are of the claw type (see FIG. 2) and rotate in the scoops 11, 12, 13, which are formed by the shields 14 to 17 and the housing rings 18 to 20.
  • the drive motor 22 is located next to the vertically arranged pump housing. Below the lower bearing plate 17, the shafts 2, 3 are equipped with gear wheels 23, 24 of the same diameter, which are used to synchronize the movement of the rotor pairs 4, 5 or 6, 7 or 8, 9 serve.
  • the drive motor 22 also has a gearwheel 25 on its underside. The drive connection is established by a further gearwheel 26 which is in engagement with the gearwheels 24 and 25.
  • the shafts 2, 3 are supported by roller bearings 27.
  • the upper end plate 14 is equipped with a horizontally arranged connecting flange 28, which forms the inlet 29 of the pump.
  • the inlet channel 31 opens at the end (opening 32) into the scoop chamber 11 of the first stage.
  • the one on the front The outlet opening of the first stage is designated 33 and leads into the connecting channel 34.
  • the connecting channel 34 located in the shield 15 is connected to the inlet opening 35 of the second stage.
  • the end shield 16 is designed accordingly.
  • Below the lowermost (third) pump stage is the outlet 36, which is connected to the front outlet opening 37 in the lower bearing plate 17.
  • Figure 2 shows the contour of the rotors. They each have a claw 41, 42 and a recess 43, 44 and carry out their rotary movement according to the arrows 45 in a meshing and contactless manner.
  • the gap seal located between the two rotors is designated by 46.
  • the control of the inlet opening 32, 35 and the outlet opening 33, 37 takes place via the respective recess 43, 44.
  • the rotors form two spaces 47 and 48, of which the enlarging space 47 is connected to the inlet opening 32, 35 .
  • the space 47 therefore forms the suction side.
  • the shrinking space 48 is connected to the outlet 33, 37 after a slight rotational movement. The space 48 thus forms the pressure side.
  • the mouth 49 of a purge gas line is on the pressure side 48.
  • the mouth 49 is located in the immediate vicinity of the sealing gap 46 between the two rotors, so that this sealing gap is preferably kept free of solid particles.
  • Figure 1 shows that the scoops 11, 12, 13 are assigned a plurality of mouths 49.
  • the scooping chamber 12 there are, for example, two openings 49, directly opposite one another in the respective side plates 15, 16.
  • the desired effect of keeping solid particles in suspension is achieved in a particularly favorable manner.
  • the orifices 49 are connected to a purge gas source 51, specifically via bores 52, 53 in the side plates 15, 16 and via the line system 54 provided outside the pump with the valve 55.
  • Nozzles are located in the bores 52, 53, which are only shown schematically 56, 57, which serve on the one hand to reduce the amount of gas supplied and on the other hand to increase the speed of the gas.
  • a suitable purge gas is nitrogen, for example.

Description

Die Erfindung bezieht sich auf eine Zweiwellenvakuumpumpe mit einem im Schöpfraum rotierenden Klauenrotorpaar, das gemeinsam mit der Schöpfraumwandung eine Saugseite und eine Druckseite bildet.The invention relates to a twin-shaft vacuum pump with a pair of claw rotors rotating in the suction chamber, which together with the suction chamber wall forms a suction side and a pressure side.

Aus der EP-A-0 290 662 ist eine Zweiwellenvakuumpumpe dieser Gattung bekannt. Die Rotoren sind jeweils mit einer Klaue (Zahn) und einer Aussparung ausgerüstet und führen ihre Drehbewegung kämmend und berührungsfrei im Schöpfraum aus. Die jeweiligen Aussparungen steuern die in den Seitenschilden des Schöpfraumes befindlichen Einlaß- und Auslaßöffnungen. Während der synchronen Drehbewegung der Rotoren bilden sich durch Spaltöffnungen abgedichtete, sich zunächst vergrößernde und dann wieder verkleinernde Räume aus, die das auf der Saugseite eingeströmte Gas verdichten und zur Druckseite fördern.A twin-shaft vacuum pump of this type is known from EP-A-0 290 662. The rotors are each equipped with a claw (tooth) and a recess and perform their rotary motion in the scooping chamber in a meshing and contact-free manner. The respective cutouts control the inlet and outlet openings located in the side plates of the scoop chamber. During the synchronous rotary movement of the rotors, spaces are formed which are sealed by stomata, which initially enlarge and then shrink again, which compress the gas flowing in on the suction side and convey it to the pressure side.

Der wesentliche Vorteil von Zweiwellenvakuumpumpen der beschriebenen Gattung ist, daß sie trocken, d. h. ohne Dichtmittel im Schöpfraum, betrieben werden können. Pumpen dieser Art werden deshalb häufig zur Evakuierung von Vakuumkammern eingesetzt, in denen Ätz-, Beschichtungs- oder andere Vakuumbehandlungs- oder -herstellverfahren durchgeführt werden. Bei derartigen Einsätzen besteht die Gefahr, daß Feststoffe in die Pumpe gelangen, und zwar auch mittelbar, d. h. daß sich Feststoffpartikel erst während der Verdichtung der Gase, also während des Durchtritts der abzuführenden Gase durch die Vakuumpumpe, bilden. Beispiele dafür sind die Entstehung von Aluminiumchlorid beim Aluminium-Ätzen, Amoniumchlorid bei Beschichtungsverfahren usw.The main advantage of twin-shaft vacuum pumps of the type described is that they can be operated dry, ie without sealant in the pumping chamber. Pumps of this type are therefore often used for evacuating vacuum chambers in which etching, coating or other vacuum treatment or manufacturing processes are carried out. In such operations there is a risk that solids get into the pump, and although also indirectly, that is to say that solid particles only form during the compression of the gases, that is to say during the passage of the gases to be discharged through the vacuum pump. Examples include the formation of aluminum chloride in aluminum etching, ammonium chloride in coating processes, etc.

Unmittelbar oder mittelbar in die Vakuumpumpe gelangende Feststoffpartikel lagern sich im Schöpfraum ab, unter anderem auch auf den peripheren Oberflächen der Rotoren, wo sie zunächst den zwischen den Rotoren befindlichen Spalt verengen. Weitere Ablagerungen führen dazu, daß sich die Rotoren berühren, was zu einem Aufwalzen der Feststoffpartikel auf die Rotoroberflächen führt. Nehmen die Ablagerungen weiter zu, dann kommt es zu einer Verdickung der aufgewalzten Schicht, so daß eine die Rotoren und damit die Rotorwellen auseinanderdrückende Kraft entsteht. Diese führt insbesondere bei einem weiteren Anwachsen der aufgewalzten Schicht zu Lagerschäden und damit zum Ausfall der Pumpe.Solid particles that get directly or indirectly into the vacuum pump are deposited in the scooping chamber, including on the peripheral surfaces of the rotors, where they initially narrow the gap between the rotors. Further deposits cause the rotors to touch, which causes the solid particles to roll onto the rotor surfaces. If the deposits continue to increase, the rolled-on layer is thickened, so that a force is produced which pushes the rotors and thus the rotor shafts apart. This leads to bearing damage and thus to the failure of the pump, particularly if the rolled layer continues to grow.

Der vorliegenden Erfindung liegt die Aufgabe zugrunde, bei einer Zweiwellenvakuumpumpe der eingangs erwähnten Art zu verhindern, daß sich in die Vakuumpumpe gelangende Feststoffpartikel im Schöpfraum ablagern.The present invention has for its object to prevent in a twin-shaft vacuum pump of the type mentioned that solid particles entering the vacuum pump accumulate in the scoop.

Erfindungsgemäß wird diese Aufgabe dadurch gelöst, daß eine Spülgasleitung druckseitig in den Schöpfraum mündet. Wird während des Betriebs der Pumpe über diese Spülgasleitung ein Spülgas zugeführt, dann verhindern im Schöpfraum entstehende Gaswirbel die Ablagerung von in den Schöpfraum gelangenden Feststoffpartikeln. Die Menge des zugeführten Spülgases muß nicht sehr hoch sein, da sonst der Enddruck der Pumpe unnötig verschlechtert würde. Von besonderem Vorteil ist, wenn das Spülgas mit hoher Geschwindigkeit, z. B. über eine Düse, zugeführt wird. Die infolge der entstehenden Wirbel in Schwebe gehaltenen Feststoffpartikel können dann zur nächsten Pumpenstufe oder zum Pumpenausgang gefördert werden.According to the invention, this object is achieved in that a purge gas line opens on the pressure side into the scoop. If a flushing gas is supplied via this flushing gas line during operation of the pump, gas vortices arising in the scooping chamber prevent the deposition of solid particles entering the scooping chamber. The amount of purge gas supplied does not have to be very high, since otherwise the final pressure of the pump would be unnecessarily deteriorated. It is particularly advantageous if the purge gas at high speed, for. B. is supplied via a nozzle. The solid particles which are kept in suspension as a result of the eddies which are produced can then be conveyed to the next pump stage or to the pump outlet.

Zweckmäßig befindet sich die Spülgasleitung in unmittelbarer Nähe der Spaltdichtung der beiden Rotoren. Dadurch werden die besonders gefährdeten peripheren Oberflächen der beiden Rotoren von Ablagerungen freigehalten.The purge gas line is expediently located in the immediate vicinity of the gap seal of the two rotors. As a result, the particularly endangered peripheral surfaces of the two rotors are kept free of deposits.

Weitere Vorteile und Einzelheiten der Erfindung sollen anhand von in den Figuren 1 und 2 dargestellten Ausführungsbeispielen erläutert werden. Es zeigen

  • Figur 1 einen Längs schnitt durch eine mehrstufige Pumpe nach der Erfindung und
  • Figur 2 einen Schnitt durch einen der Schöpfräume parallel zu einem Rotorpaar.
Further advantages and details of the invention will be explained on the basis of the exemplary embodiments illustrated in FIGS. 1 and 2. Show it
  • Figure 1 shows a longitudinal section through a multi-stage pump according to the invention and
  • Figure 2 shows a section through one of the scoops parallel to a pair of rotors.

Bei dem in Figur 1 dargestellten Ausführungsbeispiel handelt es sich um eine dreistufige Vakuumpumpe 1 mit zwei Wellen 2 und 3 sowie drei Rotorpaaren 4, 5 bzw. 6, 7 bzw. 8, 9. Die axiale Länge der Rotoren nimmt von der Saugseite zur Druckseite ab. Die Drehkolben sind vom Klauentyp (vergl. Figur 2) und rotieren in den Schöpfräumen 11, 12, 13, welche von den Schilden 14 bis 17 und den Gehäuseringen 18 bis 20 gebildet werden.The exemplary embodiment shown in FIG. 1 is a three-stage vacuum pump 1 with two shafts 2 and 3 and three pairs of rotors 4, 5 or 6, 7 or 8, 9. The axial length of the rotors decreases from the suction side to the pressure side . The rotary pistons are of the claw type (see FIG. 2) and rotate in the scoops 11, 12, 13, which are formed by the shields 14 to 17 and the housing rings 18 to 20.

Neben dem vertikal angeordneten Pumpengehäuse befindet sich der Antriebsmotor 22. Unterhalb des unteren Lagerschildes 17 sind die Wellen 2, 3 mit Zahnrädern 23, 24 gleichen Durchmessers ausgerüstet, welche der Synchronisation der Bewegung der Rotorpaare 4, 5 bzw. 6, 7 bzw. 8, 9 dienen. Auch der Antriebsmotor 22 weist an seiner Unterseite ein Zahnrad 25 auf. Die Antriebsverbindung wird hergestellt durch ein weiteres Zahnrad 26, das mit den Zahnrädern 24 und 25 in Eingriff steht.The drive motor 22 is located next to the vertically arranged pump housing. Below the lower bearing plate 17, the shafts 2, 3 are equipped with gear wheels 23, 24 of the same diameter, which are used to synchronize the movement of the rotor pairs 4, 5 or 6, 7 or 8, 9 serve. The drive motor 22 also has a gearwheel 25 on its underside. The drive connection is established by a further gearwheel 26 which is in engagement with the gearwheels 24 and 25.

In dem oberen Lagerschild 14 und dem unteren Lagerschild 17 stützen sich die Wellen 2, 3 über Wälzlager 27 ab. Der obere Lagerschild 14 ist mit einem horizontal angeordneten Anschlußflansch 28 ausgerüstet, welcher den Einlaß 29 der Pumpe bildet. Der Einlaßkanal 31 mündet stirnseitig (Öffnung 32) in den Schöpfraum 11 der ersten Stufe. Die stirnseitig angeordnete Auslaßöffnung der ersten Stufe ist mit 33 bezeichnet und führt in den Verbindungskanal 34. Der im Schild 15 befindliche Verbindungskanal 34 steht mit der Einlaßöffnung 35 der zweiten Stufe in Verbindung. Der Lagerschild 16 ist entsprechend gestaltet. Unterhalb der untersten (dritten) Pumpstufe befindet sich der Auslaß 36, der mit der stirnseitigen Auslaßöffnung 37 im unteren Lagerschild 17 in Verbindung steht.In the upper end plate 14 and the lower end plate 17, the shafts 2, 3 are supported by roller bearings 27. The upper end plate 14 is equipped with a horizontally arranged connecting flange 28, which forms the inlet 29 of the pump. The inlet channel 31 opens at the end (opening 32) into the scoop chamber 11 of the first stage. The one on the front The outlet opening of the first stage is designated 33 and leads into the connecting channel 34. The connecting channel 34 located in the shield 15 is connected to the inlet opening 35 of the second stage. The end shield 16 is designed accordingly. Below the lowermost (third) pump stage is the outlet 36, which is connected to the front outlet opening 37 in the lower bearing plate 17.

Figur 2 läßt sie Kontur der Rotoren erkennen. Sie weisen jeweils eine Klaue 41, 42 sowie eine Aussparung 43, 44 auf und führen ihre Drehbewegung entsprechend der Pfeile 45 kämmend und berührungsfrei aus. Die zwischen den beiden Rotoren befindliche Spaltdichtung ist mit 46 bezeichnet.Figure 2 shows the contour of the rotors. They each have a claw 41, 42 and a recess 43, 44 and carry out their rotary movement according to the arrows 45 in a meshing and contactless manner. The gap seal located between the two rotors is designated by 46.

Die Steuerung der Einlaßöffnung 32, 35 und der Auslaßöffnung 33, 37 erfolgt über die jeweilige Aussparung 43, 44. In der dargestellten Stellung bilden die Rotoren zwei Räume 47 und 48, von denen der sich vergrößernde Raum 47 mit der Einlaßöffnung 32, 35 verbunden ist. Der Raum 47 bildet deshalb die Saugseite. Der sich verkleinernde Raum 48 wird nach geringfügiger Rotationsbewegung mit dem Auslaß 33, 37 verbunden. Der Raum 48 bildet damit die Druckseite.The control of the inlet opening 32, 35 and the outlet opening 33, 37 takes place via the respective recess 43, 44. In the position shown, the rotors form two spaces 47 and 48, of which the enlarging space 47 is connected to the inlet opening 32, 35 . The space 47 therefore forms the suction side. The shrinking space 48 is connected to the outlet 33, 37 after a slight rotational movement. The space 48 thus forms the pressure side.

Erfindungsgemäß befindet sich auf der Druckseite 48 die Mündung 49 einer in Figur 2 nicht dargestellten Spülgasleitung. Die Mündung 49 befindet sich in unmittelbarer Nähe des Dichtungsspaltes 46 zwischen den beiden Rotoren, so daß vorzugsweise dieser Dichtspalt von Feststoffpartikeln freigehalten wird.According to the invention, the mouth 49 of a purge gas line, not shown in FIG. 2, is on the pressure side 48. The mouth 49 is located in the immediate vicinity of the sealing gap 46 between the two rotors, so that this sealing gap is preferably kept free of solid particles.

Figur 1 zeigt, daß den Schöpfräumen 11, 12, 13 mehrere Mündungen 49 zugeordnet sind. In dem Schöpfraum 12 befinden sich beispielsweise zwei Mündungen 49, und zwar direkt einander gegenüberliegend in den jeweiligen Seitenschilden 15, 16. Die gewünschte Wirkung, Feststoffpartikel in Schwebe zu halten, wird dadurch in besonders günstiger Weise erreicht.Figure 1 shows that the scoops 11, 12, 13 are assigned a plurality of mouths 49. In the scooping chamber 12 there are, for example, two openings 49, directly opposite one another in the respective side plates 15, 16. The desired effect of keeping solid particles in suspension is achieved in a particularly favorable manner.

Die Mündungen 49 stehen mit einer Spülgasquelle 51 in Verbindung, und zwar über Bohrungen 52, 53 in den Seitenschilden 15, 16 und über das außerhalb der Pumpe vorgesehene Leitungssystem 54 mit dem Ventil 55. In den nur schematisch dargestellten Bohrungen 52, 53 befinden sich Düsen 56, 57, die zum einen der Reduzierung der zugeführten Gasmenge und zum anderen der Erhöhung der Geschwindigkeit des Gases dienen. Ein geeignetes Spülgas ist beispielsweise Stickstoff.The orifices 49 are connected to a purge gas source 51, specifically via bores 52, 53 in the side plates 15, 16 and via the line system 54 provided outside the pump with the valve 55. Nozzles are located in the bores 52, 53, which are only shown schematically 56, 57, which serve on the one hand to reduce the amount of gas supplied and on the other hand to increase the speed of the gas. A suitable purge gas is nitrogen, for example.

Claims (7)

  1. Twin-shaft vacuum pump (1) with a claw rotor pair (4, 5; 6, 7; 8, 9), which rotates in the suction chamber (11, 12, 13) and, together with the suction chamber wall, defines a suction side (47) associated with the inlet aperture (32, 35) and a pressure side (48) associated with the outlet aperture (33, 37), characterised in that the opening (49) of a flushing gas pipe (52, 53) is located on the pressure side (48) of the suction chamber (11, 12, 13).
  2. Pump according to claim 1, characterised in that the opening (49) is located in a side plate (15, 16, 17).
  3. Pump according to claim 2, characterised in that the opening (49) is located in the immediate proximity of the gap seal (46) between the two rotors (4, 5; 6, 7; 8, 9).
  4. Pump according to claim 1, 2 or 3, characterised in that two openings (49) are provided.
  5. Pump according to claim 2 and claim 4, characterised in that the two openings (49) are located opposite one another in two side plates (15, 16) defining the suction chamber (12).
  6. Pump according to one of the preceding claims, characterised in that, as well as a pipe system, the openings (49) are connected to a flushing gas source (51) via bores (52, 53) in the side plates (15, 16).
  7. Pump according to claim 6, characterised in that a nozzle (56, 57) is located inside the bore (52, 53).
EP88117651A 1988-10-24 1988-10-24 Positive displacement twin-shaft vacuum pump Expired - Lifetime EP0365695B1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
DE8888117651T DE3876243D1 (en) 1988-10-24 1988-10-24 TWO-SHAFT VACUUM PUMP WITH SCHOEPFRAUM.
EP88117651A EP0365695B1 (en) 1988-10-24 1988-10-24 Positive displacement twin-shaft vacuum pump
JP1275119A JPH02153292A (en) 1988-10-24 1989-10-24 Two spindle type vacuum pump with suction chamber
US07/481,853 US5046934A (en) 1988-10-24 1990-02-20 Twin shaft vacuum pump with purge gas inlet

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP88117651A EP0365695B1 (en) 1988-10-24 1988-10-24 Positive displacement twin-shaft vacuum pump

Publications (2)

Publication Number Publication Date
EP0365695A1 EP0365695A1 (en) 1990-05-02
EP0365695B1 true EP0365695B1 (en) 1992-11-25

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP88117651A Expired - Lifetime EP0365695B1 (en) 1988-10-24 1988-10-24 Positive displacement twin-shaft vacuum pump

Country Status (4)

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US (1) US5046934A (en)
EP (1) EP0365695B1 (en)
JP (1) JPH02153292A (en)
DE (1) DE3876243D1 (en)

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US5046934A (en) 1991-09-10
DE3876243D1 (en) 1993-01-07
JPH02153292A (en) 1990-06-12
EP0365695A1 (en) 1990-05-02

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