EP0370117B1 - Two-shaft vacuum pump and method of operation - Google Patents

Two-shaft vacuum pump and method of operation Download PDF

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Publication number
EP0370117B1
EP0370117B1 EP88117650A EP88117650A EP0370117B1 EP 0370117 B1 EP0370117 B1 EP 0370117B1 EP 88117650 A EP88117650 A EP 88117650A EP 88117650 A EP88117650 A EP 88117650A EP 0370117 B1 EP0370117 B1 EP 0370117B1
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EP
European Patent Office
Prior art keywords
rotor
outlet
recess
scooping
opening
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
EP88117650A
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German (de)
French (fr)
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EP0370117A1 (en
Inventor
Hanns-Peter Dr. Berges
Wolfgang Leier
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
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Filing date
Publication date
Application filed by Leybold AG filed Critical Leybold AG
Priority to DE88117650T priority Critical patent/DE3887149D1/en
Priority to EP88117650A priority patent/EP0370117B1/en
Priority to JP1275118A priority patent/JP2755733B2/en
Priority to US07/482,151 priority patent/US5049050A/en
Publication of EP0370117A1 publication Critical patent/EP0370117A1/en
Application granted granted Critical
Publication of EP0370117B1 publication Critical patent/EP0370117B1/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
    • 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

Definitions

  • the invention relates to a method for operating a two-shaft vacuum pump according to the preamble of claim 1.
  • the invention relates to a two-shaft vacuum pump suitable for carrying out this operating method (claim 2).
  • a twin-shaft vacuum pump of this type is known from the older, not prepublished EP-A-0.290.662.
  • the rotors are each equipped with a protrusion (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.
  • the present invention has for its object to provide an operating method for a twin-shaft vacuum pump according to the Northey principle and to design a twin-shaft vacuum pump of this type so that it can be flushed with a gas during operation without the gas flushing the pump properties (Final pressure, pumping speed, etc.) significantly affected.
  • FR-A-21 09 789 belongs to the prior art.
  • the majority of the nozzles are always open. Only some of the nozzles on the side are swept by one of the two rotors (main rotor); however, this is not intended to shut off or control the supply of the liquid into the working space, but rather to provide an effective axial seal of the rotor against the side wall.
  • the exemplary embodiment shown in FIG. 1 is a three-stage vacuum pump 1 with two shafts 2 and 3 and three rotor pairs 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 gear 26, which is in engagement with the gears 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 in the first stage.
  • the end opening of the first stage is designated 33 and leads into the connecting duct 34.
  • the connecting duct 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 lowest (third) pump stage is the outlet 36, which is connected to the front outlet opening 37 in the lower end shield 17.
  • the rotors are each provided with a projection 38 and a recess 39. Otherwise, they have the shape of a circular disc with the radius r1. They rotate in a meshing and contactless manner about the axes 40 and 41 in their respective scoops 11, 12, 13.
  • the recesses 39 are used to control the inlet and outlet.
  • the inlet opening 35 is assigned to the inlet-side rotor 6, and the outlet opening 42 is assigned to the outlet-side rotor 7.
  • the two rotors always form two spaces (scooping volumes) 43, 44, of which the enlarging space 43 is connected to the inlet opening 35.
  • the space 44 which is reduced as a result of the rotor rotation is connected to the outlet opening 42.
  • the mouth 45 of a purge gas line is located in the scoop chamber 12.
  • part of the purge gas line is formed by a longitudinal bore 46 and a transverse bore 47 in the side plate 16.
  • the transverse bore 47 leads to orifices 45, 48 located in the scoops 12, 13, so that both outlet-side stages of the multi-stage two-shaft vacuum pump 1 can be supplied with purge gas.
  • the bore 46 is via a line 49 outside the pump 1 with a purge gas supply 51, for. B. a nitrogen bottle in connection.
  • Figures 2 to 4 show the exact position of the mouth 45 in the scoop 12. It is assigned to the outlet-side rotor 7 and lies on a circle around the axis 41 with the radius r2, on which the outlet opening 42 is also located. This makes it possible to control the purge gas supply by means of the recess 39 in the rotor 7.
  • the position of the mouth 45 is selected so that the respective scooping volume at the moment of the supply of purge gas ( Figure 3) is completed both towards the inlet opening and towards the outlet opening. This condition is fulfilled when the mouth 45 of the purge gas line is upstream of the outlet opening 42 with respect to the rotary movement of the rotor 7.
  • the angle ⁇ which is determined by the position of the purge gas mouth 45 and the start of the outlet opening 42, must be greater than the angle ⁇ , which is due to the width the recess 39 in the rotor 7 is determined.
  • the maximum size of the angle ⁇ is given by the necessary condition that at no time a short circuit between the inlet 35 and the purge gas mouth 45 may exist.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)
  • Compressors, Vaccum Pumps And Other Relevant Systems (AREA)

Description

Die Erfindung bezieht sich auf ein Verfahren zum Betrieb einer Zweiwellenvakuumpumpe entsprechend dem Oberbegriff des Patentanspruchs 1. Außerdem bezieht sich die Erfindung auf eine für die Durchführung dieses Betriebsverfahrens geeignete Zweiwellenvakuumpumpe (Patentanspruch 2).The invention relates to a method for operating a two-shaft vacuum pump according to the preamble of claim 1. In addition, the invention relates to a two-shaft vacuum pump suitable for carrying out this operating method (claim 2).

Aus der älteren, nicht vorveröffentlichten EP-A-0.290.662 ist eine Zweiwellenvakuumpumpe dieser Gattung bekannt. Die Rotoren sind jeweils mit einem Vorsprung (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 Schöpfvolumina aus, die das auf der Saugseite einströmende Gas verdichten und zur Druckseite fördern.A twin-shaft vacuum pump of this type is known from the older, not prepublished EP-A-0.290.662. The rotors are each equipped with a protrusion (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, scooping volumes which are sealed by stomata, initially enlarge and then reduce again form, which compress the gas flowing in on the suction side and convey it to the pressure side.

Der vorliegenden Erfindung liegt die Aufgabe zugrunde, ein Betriebsverfahren für eine Zweiwellenvakuumpumpe nach dem Northey-Prinzip anzugeben und eine Zweiwellenvakuumpumpe dieser Art so zu gestalten, daß sie auch während des Betriebs mit einem Gas gespült werden kann, ohne daß die Gasspülung die Pumpeigenschaften (Enddruck, Saugvermögen usw.) maßgeblich beeinträchtigt.The present invention has for its object to provide an operating method for a twin-shaft vacuum pump according to the Northey principle and to design a twin-shaft vacuum pump of this type so that it can be flushed with a gas during operation without the gas flushing the pump properties (Final pressure, pumping speed, etc.) significantly affected.

Erfindungsgemäß wird diese Aufgabe durch die in den Patentansprüchen 1 und 2 enthaltenen Maßnahmen gelöst. Bei einer in dieser Weise betriebenen bzw. ausgebildeten Zweiwellenvakuumpumpe kann in das jeweils zum Auslaß geförderte Schöpfvolumen Spülgas eingelassen werden, ohne daß dieser Spülgaseinlaß den Enddruck oder das Saugvermögen der Pumpe beeinträchtigt. Mit Hilfe des Spülgases können staubförmige Partikel in der Schwebe gehalten und ausgefördert werden, die sich sonst auf den Kolben oder an den Schöpfraumwänden ablagern würden. Ein Spülgaseinlaß ist besonders vorteilhaft, wenn mit Hilfe der Pumpe reaktive Gase (z.B. CCL₄, BCL₃, HCL, O₂ oder dergleichen) gefördert werden. Mit Hilfe des Spülgases kann die Reaktivität der Gase in erheblichem Maße reduziert werden. Dadurch, daß das Spülgas immer nur dann in das Schöpfvolumen eingelassen wird, wenn die Einlaßöffnung bereits geschlossen und die Auslaßöffnung noch nicht offen ist, sind die Pumpeigenschaften nicht beeinträchtigt.According to the invention, this object is achieved by the measures contained in claims 1 and 2. In a two-shaft vacuum pump operated or designed in this way, flushing gas can be introduced into the respective scoop volume delivered to the outlet without this flushing gas inlet impairing the final pressure or the pumping speed of the pump. With the help of the purge gas, dust-like particles can be kept in suspension and removed, which would otherwise be deposited on the pistons or on the walls of the suction chamber. A purge gas inlet is particularly advantageous if reactive gases (e.g. CCL₄, BCL₃, HCL, O₂ or the like) are conveyed using the pump. With the help of the purge gas, the reactivity of the gases can be reduced considerably. Because the purge gas is only admitted into the scoop volume when the inlet opening is already closed and the outlet opening is not yet open, the pump properties are not impaired.

Aus der älteren, nicht vorveröffentlichten EP-A-338 767 ist es bekannt, in einer mehrstufigen ölfreien Vakuumpumpe einen zirkulierenden Spülgasstrom zu erzeugen. Eine Lehre darüber, wie der in einzelne Stufen mündende Spülgaseinlaß angeordnet sein muß, damit die Pumpeigenschaften nicht beeinträchtigt sind, enthält dieses Dokument nicht.From the older, not previously published EP-A-338 767 it is known to generate a circulating purge gas stream in a multi-stage oil-free vacuum pump. This document does not contain a teaching on how the purge gas inlet opening into individual stages must be arranged so that the pump properties are not impaired.

Zum Stand der Technik gehört der Inhalt der FR-A-21 09 789. Diese offenbart einen Kompressor, in dessen Arbeitsraum über eine Vielzahl von seitlich und peripher gelegenen Düsen eine Flüssigkeit eingespritzt wird, die eine Kühl-, Dicht- und/oder Schmierfunktion hat. Die Mehrzahl der Düsen ist ständig offen. Nur einige der seitlich gelegenen Düsen werden von einem der beiden Rotoren (Hauptrotor) überstrichen; dadurch soll jedoch keine Absperrung oder Steuerung der Zufuhr der Flüssigkeit in den Arbeitsraum sondern eine wirksame axiale Abdichtung des Rotors gegenüber der Seitenwand erreicht werden.The content of FR-A-21 09 789 belongs to the prior art. This discloses a compressor, in the working space of which a liquid is injected via a plurality of laterally and peripherally located nozzles, which has a cooling, sealing and / or lubricating function . The majority of the nozzles are always open. Only some of the nozzles on the side are swept by one of the two rotors (main rotor); however, this is not intended to shut off or control the supply of the liquid into the working space, but rather to provide an effective axial seal of the rotor against the side wall.

Weitere Vorteile und Einzelheiten der Erfindung sollen anhand von in den Figuren 1 bis 4 dargestellten Ausführungsbeispielen erläutert werden. Es zeigen

  • Figur 1 einen Längsschnitt durch eine mehrstufige Pumpe nach der Erfindung und die
  • Figuren 2 bis 4 Schnitte in Höhe des mittleren Rotorpaares.
Further advantages and details of the invention will be explained on the basis of the exemplary embodiments illustrated in FIGS. 1 to 4. Show it
  • 1 shows a longitudinal section through a multi-stage pump according to the invention and the
  • Figures 2 to 4 sections at the level of the middle 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 (vgl. 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 rotor pairs 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 gear 26, which is in engagement with the gears 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 in 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 in the first stage. The end opening of the first stage is designated 33 and leads into the connecting duct 34. The connecting duct 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 lowest (third) pump stage is the outlet 36, which is connected to the front outlet opening 37 in the lower end shield 17.

Anhand der Figur 2 ist ersichtlich, daß die Rotoren jeweils mit einem Vorsprung 38 und einer Aussparung 39 versehen sind. Im übrigen haben sie die Form einer Kreisscheibe mit dem Radius r₁. Sie rotieren kämmend und berührungsfrei um die Achsen 40 und 41 in ihren jeweiligen Schöpfräumen 11, 12, 13.It can be seen from FIG. 2 that the rotors are each provided with a projection 38 and a recess 39. Otherwise, they have the shape of a circular disc with the radius r₁. They rotate in a meshing and contactless manner about the axes 40 and 41 in their respective scoops 11, 12, 13.

Mittels der Aussparungen 39 erfolgt die Steuerung von Einlaß und Auslaß. Dem einlaßseitigen Rotor 6 ist die Einlaßöffnung 35, dem auslaßseitigen Rotor 7 ist die Auslaßöffnung 42 zugeordnet. Die beiden Rotoren bilden stets zwei Räume (Schöpfvolumina) 43, 44, von denen der sich vergrößernde Raum 43 mit der Einlaßöffnung 35 verbunden ist. Der sich infolge der Rotordrehung verkleinernde Raum 44 wird mit der Auslaßöffnung 42 verbunden.The recesses 39 are used to control the inlet and outlet. The inlet opening 35 is assigned to the inlet-side rotor 6, and the outlet opening 42 is assigned to the outlet-side rotor 7. The two rotors always form two spaces (scooping volumes) 43, 44, of which the enlarging space 43 is connected to the inlet opening 35. The space 44 which is reduced as a result of the rotor rotation is connected to the outlet opening 42.

Erfindungsgemäß befindet sich im Schöpfraum 12 die Mündung 45 einer Spülgasleitung. In Figur 1 ist angedeutet, daß ein Teil der Spülgasleitung von einer Längsbohrung 46 und einer Querbohrung 47 im Seitenschild 16 gebildet wird. Die Querbohrung 47 führt zu in den Schöpfräumen 12, 13 gelegenen Mündungen 45, 48, so daß beide auslaßseitigen Stufen der mehrstufigen Zweiwellenvakuumpumpe 1 mit Spülgas versorgt werden können. Die Bohrung 46 steht über eine außerhalb der Pumpe 1 geführte Leitung 49 mit einem Spülgasvorrat 51, z. B. einer Stickstoffflasche in Verbindung.According to the invention, the mouth 45 of a purge gas line is located in the scoop chamber 12. In Figure 1 it is indicated that part of the purge gas line is formed by a longitudinal bore 46 and a transverse bore 47 in the side plate 16. The transverse bore 47 leads to orifices 45, 48 located in the scoops 12, 13, so that both outlet-side stages of the multi-stage two-shaft vacuum pump 1 can be supplied with purge gas. The bore 46 is via a line 49 outside the pump 1 with a purge gas supply 51, for. B. a nitrogen bottle in connection.

Die Figuren 2 bis 4 zeigen die genaue Lage der Mündung 45 im Schöpfraum 12. Sie ist dem auslaßseitigen Rotor 7 zugeordnet und liegt auf einem Kreis um die Achse 41 mit dem Radius r₂, auf dem auch die Auslaßöffnung 42 liegt. Dadurch ist es möglich, auch die Spülgaszufuhr mittels der Aussparung 39 im Rotor 7 zu steuern. Im übrigen ist die Lage der Mündung 45 so gewählt, daß das jeweilige Schöpfvolumen im Moment der Zufuhr von Spülgas (Figur 3) sowohl zur Einlaßöffnung hin als auch zur Auslaßöffnung hin abgeschlossen ist. Diese Bedingung ist dann erfüllt, wenn die Mündung 45 der Spülgasleitung der Auslaßöffnung 42 - in Bezug auf die Drehbewegung des Rotors 7 - vorgelagert ist. Damit zwischen der Auslaßöffnung 42 und der Mündung 45 der Spülgasleitung zu keinem Zeitpunkt ein Kurzschluß besteht, muß der Winkel α, der durch die Lage der Spülgasmündung 45 und dem Beginn der Auslaßöffnung 42 bestimmt ist, größer sein als der Winkel β, der durch die Breite der Aussparung 39 im Rotor 7 bestimmt ist. Die maximale Größe des Winkels α ist durch die notwendige Bedingung gegeben, daß zu keinem Zeitpunkt ein Kurzschluß zwischen dem Einlaß 35 und der Spülgasmündung 45 bestehen darf.Figures 2 to 4 show the exact position of the mouth 45 in the scoop 12. It is assigned to the outlet-side rotor 7 and lies on a circle around the axis 41 with the radius r₂, on which the outlet opening 42 is also located. This makes it possible to control the purge gas supply by means of the recess 39 in the rotor 7. In addition, the position of the mouth 45 is selected so that the respective scooping volume at the moment of the supply of purge gas (Figure 3) is completed both towards the inlet opening and towards the outlet opening. This condition is fulfilled when the mouth 45 of the purge gas line is upstream of the outlet opening 42 with respect to the rotary movement of the rotor 7. So that there is never a short circuit between the outlet opening 42 and the mouth 45 of the purge gas line, the angle α, which is determined by the position of the purge gas mouth 45 and the start of the outlet opening 42, must be greater than the angle β, which is due to the width the recess 39 in the rotor 7 is determined. The maximum size of the angle α is given by the necessary condition that at no time a short circuit between the inlet 35 and the purge gas mouth 45 may exist.

Claims (4)

  1. A method for operating a two-shaft vacuum pump (1) according to the Northey principle, with two rotors (4, 5; 6, 7; 8, 9), which rotate in synchronism and without contact in a scooping chamber (11, 12, 13) and are provided in each case with a projection (38) and a recess (39), one of the said rotors controlling an inlet opening (32, 35) and the other an outlet opening (33, 37, 42), the two rotors forming two chambers (scooping volumes 43, 44) as they rotate, the enlarging chamber (43) being connected to the inlet opening (35) and the reducing chamber (44) to the outlet opening (42), characterised in that rinsing gas is introduced into the respective reducing scooping volume (44) which is conveyed towards the outlet, the rinsing gas only being introduced when the said scooping volume (44) is sealed relative to both the inlet opening (35) and the outlet opening (42), and the supply of rinsing gas being controlled with the aid of the outlet-side rotor (5, 7, 9).
  2. Pump for carrying out the method according to claim 1, with two rotors (4, 5; 6, 7; 8, 9), which rotate in synchronism and without contact in a scooping chamber (11, 12, 13),
    - the rotors are mounted in each case so as to rotate about an axis (40, 41),
    - the rotors are provided in each case with a projection (38) and a recess (39),
    - associated with one (6) of the rotors (6, 7) is a suction opening (32, 35) in a side panel (14, 15, 16) defining the scooping chamber, the suction opening being arranged at a distance from pivot axis (40) corresponding to the distance of the recess (39) in the rotor (6) from the pivot axis (40), so that the recess (39) in the rotor (6) controls the suction opening (32, 35),
    - an outlet opening (33, 42, 37) is associated with the other rotor (7), the said outlet opening being arranged at a distance from the pivot axis (41) corresponding to the distance of the recess (39) in the rotor (7) from the pivot axis (41), so that the recess (39) in the rotor (7) controls the outlet opening (33, 42, 37), characterised in that
    - a rinsing gas line (46, 47) opens into the scooping chamber,
    - the mouth (45, 48) of the rinsing gas line is associated with the outlet-side rotor (5, 7, 9),
    - the distance of the mouth (45, 48) from the pivot axis (41) corresponds to the distance of the recess (39) in the rotor (7) from the pivot axis (41), so that the recess (39) in the rotor (7) also controls the rinsing gas supply and
    - the position of the mouth (45, 48) of the rinsing gas line (46, 47) is selected in such a manner that the respective reducing scooping volume which is conveyed towards the outlet is sealed relative to the inlet opening (35) and the outlet opening (42) at the moment when the rinsing gas is supplied.
  3. Pump according to claim 2, characterised in that the outlet opening (42) and the mouth (45, 48) of the rinsing gas line lie along a circle around the pivot axis (41) of the outlet-side rotor (5, 7, 9), the mouth (45, 48) is arranged upstream of the outlet opening (42) - in relation to the rotational movement of the rotor - and the angle (α), which is determined by the position of the mouth (45, 48) and the start of the outlet opening (42), is greater than the angle (β), which is determined by the width of the recess in the rotor.
  4. Pump according to claim 2 or 3, characterised in that it is constructed in three stages and a mouth (45, 48) of a rinsing gas line (46, 47) is provided in each case in the scooping chambers (12, 13) of the outlet-side pump stages.
EP88117650A 1988-10-24 1988-10-24 Two-shaft vacuum pump and method of operation Expired - Lifetime EP0370117B1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
DE88117650T DE3887149D1 (en) 1988-10-24 1988-10-24 Twin-shaft vacuum pump and method for its operation.
EP88117650A EP0370117B1 (en) 1988-10-24 1988-10-24 Two-shaft vacuum pump and method of operation
JP1275118A JP2755733B2 (en) 1988-10-24 1989-10-24 Method of operating a two-shaft vacuum pump and two-shaft vacuum pump
US07/482,151 US5049050A (en) 1988-10-24 1990-02-20 Method for operating a twin shaft vacuum pump according to the Northey principle and a twin shaft vacuum pump suitable for the implementation of the method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP88117650A EP0370117B1 (en) 1988-10-24 1988-10-24 Two-shaft vacuum pump and method of operation

Publications (2)

Publication Number Publication Date
EP0370117A1 EP0370117A1 (en) 1990-05-30
EP0370117B1 true EP0370117B1 (en) 1994-01-12

Family

ID=8199480

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88117650A Expired - Lifetime EP0370117B1 (en) 1988-10-24 1988-10-24 Two-shaft vacuum pump and method of operation

Country Status (4)

Country Link
US (1) US5049050A (en)
EP (1) EP0370117B1 (en)
JP (1) JP2755733B2 (en)
DE (1) DE3887149D1 (en)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4038704C2 (en) * 1990-12-05 1996-10-10 K Busch Gmbh Druck & Vakuum Dr Rotary lobe pump
KR100203019B1 (en) * 1991-03-04 1999-06-15 우도 벡; 클라우스 한, 파울 바흐만 Device for supplying a multi-stage dry-running vacuum pump with inert gas
DE19819538C2 (en) 1998-04-30 2000-02-17 Rietschle Werner Gmbh & Co Kg Pressure suction pump
JP2001304115A (en) * 2000-04-26 2001-10-31 Toyota Industries Corp Gas feeding device for vacuum pump
EP1552152B1 (en) * 2002-10-14 2013-03-20 Edwards Limited Rotary piston vacuum pump with washing installation
JP3991918B2 (en) * 2003-05-19 2007-10-17 株式会社豊田自動織機 Roots pump
KR20100091063A (en) * 2009-02-09 2010-08-18 삼성전자주식회사 Apparatus for cleaning rotation body and vaccum pump having the same
DE202014007117U1 (en) 2014-09-05 2015-12-09 Oerlikon Leybold Vacuum Gmbh claw pump
GB201701000D0 (en) 2017-01-20 2017-03-08 Edwards Ltd Multi-stage vacuum booster pump coupling

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1915269A1 (en) * 1969-03-26 1970-10-08 Siemens Ag Roots blower
SE351012B (en) * 1970-10-01 1972-11-13 Atlas Copco Ab
GB2111126A (en) * 1981-12-09 1983-06-29 British Oxygen Co Ltd Rotary positive-displacement fluid-machines
JPS60256584A (en) * 1984-05-30 1985-12-18 Honjiyou Chem Kk High vacuum device
JPS62157289A (en) * 1985-12-29 1987-07-13 Anretsuto:Kk Roots blower for high vacuum
GB8625337D0 (en) * 1986-10-22 1986-11-26 Utile Eng Co Ltd Pumps
DE3785192D1 (en) * 1987-05-15 1993-05-06 Leybold Ag TWO-SHAFT VACUUM PUMP WITH SCHOEPFRAUM.

Also Published As

Publication number Publication date
EP0370117A1 (en) 1990-05-30
JPH02153291A (en) 1990-06-12
US5049050A (en) 1991-09-17
DE3887149D1 (en) 1994-02-24
JP2755733B2 (en) 1998-05-25

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