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EP0373229B1 - Mechanical vacuum pump with a spring loaded return valve - Google Patents

Mechanical vacuum pump with a spring loaded return valve Download PDF

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Publication number
EP0373229B1
EP0373229B1 EP88120714A EP88120714A EP0373229B1 EP 0373229 B1 EP0373229 B1 EP 0373229B1 EP 88120714 A EP88120714 A EP 88120714A EP 88120714 A EP88120714 A EP 88120714A EP 0373229 B1 EP0373229 B1 EP 0373229B1
Authority
EP
European Patent Office
Prior art keywords
pump
vacuum pump
mechanical vacuum
return valve
mechanical
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
EP88120714A
Other languages
German (de)
French (fr)
Other versions
EP0373229A1 (en
Inventor
Heinz-Dieter Bürger
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.)
Alcatel Hochvakuumtechnik GmbH
Original Assignee
Alcatel Hochvakuumtechnik GmbH
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 Alcatel Hochvakuumtechnik GmbH filed Critical Alcatel Hochvakuumtechnik GmbH
Publication of EP0373229A1 publication Critical patent/EP0373229A1/en
Application granted granted Critical
Publication of EP0373229B1 publication Critical patent/EP0373229B1/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
    • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
    • F04C29/12—Arrangements for admission or discharge of the working fluid, e.g. constructional features of the inlet or outlet
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04F—PUMPING OF FLUID BY DIRECT CONTACT OF ANOTHER FLUID OR BY USING INERTIA OF FLUID TO BE PUMPED; SIPHONS
    • F04F5/00—Jet pumps, i.e. devices in which flow is induced by pressure drop caused by velocity of another fluid flow
    • F04F5/54—Installations characterised by use of jet pumps, e.g. combinations of two or more jet pumps of different type

Definitions

  • the invention relates to a mechanical vacuum pump with a housing which has a vacuum-side inlet channel and a pressure-side outlet channel, the latter being provided with a spring-loaded check valve.
  • Mechanical vacuum pumps have a motor-driven displacement element, e.g. a reciprocating piston, one or more rotary pistons, a rotary valve or a gate valve. At least in the outlet channel of this pump, a spring-loaded check valve is usually provided, which allows the vacuum state of a vessel to be evacuated to be maintained after the pump has been switched off.
  • Mechanical vacuum pumps are often combined with other types of pumps, in particular diffusion pumps and molecular pumps, to achieve a higher vacuum, in which case the mechanical pump acts as a backing pump and works against atmospheric pressure.
  • the mechanical vacuum pump was already preceded by a propellant pump, in particular a water ring pump, so that the mechanical pump no longer has to work against atmospheric pressure, but against a significantly lower pressure, which has an effect on the achievable final vacuum of the mechanical pump.
  • the object of the invention is to improve a mechanical vacuum pump in the direction of a higher ultimate vacuum, while at the same time the cooling is to be improved with comparable power consumption.
  • the invention is therefore particularly suitable for dry-running rotary vane pumps, since the heating of the pump housing poses greater problems here.
  • a gas jet pump is installed in the outlet channel of the mechanical vacuum pump in the flow direction in front of the check valve.
  • the jet direction of the gas jet pump preferably runs parallel to the sealing surface of the check valve.
  • the gas jet pump acts practically only as a cooling element for the compression space, to which the outlet channel of the pump belongs.
  • the non-return valve closes the outlet channel, and the remaining molecules are caught and removed by the jet of the gas jet pump.
  • the selected embodiment relates to a rotary vane pump with a housing 1 and a rotating rotary valve 2.
  • the housing sits in an oil pan, not shown, and has an inlet 3, which can be connected to a vessel to be evacuated, and an outlet channel 4, which with a check valve 5 can be associated with the surrounding atmosphere.
  • the check valve 5 is held in the closed position by a spring 6 as long as the pressure in the outlet channel 4 does not exceed the counter pressure generated by atmospheric pressure and the spring 6.
  • a gas jet pump In the flow direction of the gases to be pumped in front of the check valve 5, a gas jet pump is seated in the outlet channel 4, the jet direction of which runs parallel to the sealing surface of the check valve 5.
  • the pump consists of an injection nozzle 7 and a collecting pipe 8 aligned therewith.
  • the nozzle 7 can be connected to a compressed air source (not shown) via a line 9 incorporated into the housing 1 of the pump, while the Collecting pipe either opens into the outside atmosphere or, as is usually the case, is connected to a treatment tank in which toxic gases from the tank to be evacuated can be separated from the air flow.
  • another gas in particular an inert gas, can also be used as the blowing agent.
  • the pump according to the invention is not comparable to the series connection of a mechanical vacuum pump and a propellant pump, since in such a series connection the propellant pump would sit behind the non-return valve 5 and all the molecules conveyed by the mechanical pump would then be sucked off by the gas jet pump.
  • the gas jet pump By integrating the gas jet pump into the mechanical vacuum pump, namely in the direction of flow in front of the non-return valve of this pump, the high suction capacity of the mechanical vacuum pump becomes fully effective with a small pressure difference between the inlet and outlet channels, while with increasing vacuum the outlet channel 4 in front of the non-return valve through Gas jet pump is brought to a value significantly below atmospheric pressure, whereby the ultimate vacuum to be achieved in the inlet channel 3 is increased by at least a factor of 10.
  • the invention is not restricted in detail to the exemplary embodiment shown.
  • the gas jet pump can also be used in conjunction with a mechanical vacuum pump of another type, e.g. a Roots pump or a gate valve pump.
  • the invention can also be used to advantage with oil-lubricated mechanical vacuum pumps.
  • the gas jet pump works not only in favor of a better final vacuum, but also as a heat-dissipating element, so that the heating of the pump is reduced.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)

Description

Die Erfindung bezieht sich auf eine mechanische Vakuumpumpe mit einem Gehäuse, das einen vakuumseitigen Einlaßkanal und einen druckseitigen Auslaßkanal aufweist, wobei letzterer mit einer federbelasteten Rückschlagklappe versehen ist.The invention relates to a mechanical vacuum pump with a housing which has a vacuum-side inlet channel and a pressure-side outlet channel, the latter being provided with a spring-loaded check valve.

Mechanische Vakuumpumpen besitzen ein motorisch angetriebenes Verdrängerglied, z.B. einen Hubkolben, einen oder mehrere Drehkolben, einen Drehschieber oder einen Sperrschieber. Zumindest im Auslaßkanal dieser Pumpe ist meist eine federbelastete Rückschlagklappe vorgesehen, die den erreichten Vakuumzustand eines zu evakuierenden Gefäßes nach dem Ausschalten der Pumpe zu erhalten erlaubt. Mechanische Vakuumpumpen werden oft zur Erzielung eines höheren Vakuums mit Pumpen anderer Bauart, insbesondere Diffusionspumpen und Molekularpumpen, kombiniert, wobei dann die mechanische Pumpe als Vorpumpe wirkt und gegen Atmosphärendruck arbeitet. In manchen Fällen wurde auch bereits der mechanischen Vakuumpumpe eine Treibmittelpumpe, insbesondere eine Wasserringpumpe vorgeschaltet, so daß die mechanische Pumpe nicht mehr gegen Atmosphärendruck, sondern gegen einen deutlich geringeren Druck arbeiten muß, was sich zugunsten des erreichbaren Endvakuums der mechanischen Pumpe auswirkt.Mechanical vacuum pumps have a motor-driven displacement element, e.g. a reciprocating piston, one or more rotary pistons, a rotary valve or a gate valve. At least in the outlet channel of this pump, a spring-loaded check valve is usually provided, which allows the vacuum state of a vessel to be evacuated to be maintained after the pump has been switched off. Mechanical vacuum pumps are often combined with other types of pumps, in particular diffusion pumps and molecular pumps, to achieve a higher vacuum, in which case the mechanical pump acts as a backing pump and works against atmospheric pressure. In some cases, the mechanical vacuum pump was already preceded by a propellant pump, in particular a water ring pump, so that the mechanical pump no longer has to work against atmospheric pressure, but against a significantly lower pressure, which has an effect on the achievable final vacuum of the mechanical pump.

Aufgabe der Erfindung ist es, eine mechanische Vakuumpumpe in Richtung auf ein höheres Endvakuum zu verbessern, wobei zugleich die Kühlung bei vergleichbarer Leistungsaufnahme verbessert werden soll. Damit eignet sich die Erfindung besonders für trocken laufende Drehschieberpumpen, da hier die Erwärmung des Pumpengehäuses größere Probleme aufwirft.The object of the invention is to improve a mechanical vacuum pump in the direction of a higher ultimate vacuum, while at the same time the cooling is to be improved with comparable power consumption. The invention is therefore particularly suitable for dry-running rotary vane pumps, since the heating of the pump housing poses greater problems here.

Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß in Strömungsrichtung vor der Rückschlagklappe eine Gasstrahlpumpe in den Auslaßkanal der mechanischen Vakuumpumpe eingebaut ist. Vorzugsweise verläuft die Strahlrichtung der Gasstrahlpumpe parallel zur Dichtfläche der Rückschlagklappe.This object is achieved in that a gas jet pump is installed in the outlet channel of the mechanical vacuum pump in the flow direction in front of the check valve. The jet direction of the gas jet pump preferably runs parallel to the sealing surface of the check valve.

Solange die Rückschlagklappe im Anfangsstadium eines Pumpvorgangs häufig geöffnet wird, wirkt die Gasstrahlpumpe praktisch nur als ein Kühlorgan für den Verdichtungsraum, zu dem der Auslaßkanal der Pumpe gehört. Mit abnehmendem Massestrom schließt die Rückschlagklappe den Auslaßkanal ab, und die restlichen Moleküle werden von dem Strahl der Gasstrahlpumpe erfaßt und abgeführt.As long as the non-return valve is frequently opened in the initial stage of a pumping process, the gas jet pump acts practically only as a cooling element for the compression space, to which the outlet channel of the pump belongs. As the mass flow decreases, the non-return valve closes the outlet channel, and the remaining molecules are caught and removed by the jet of the gas jet pump.

Die Erfindung wird nachfolgend anhand eines bevorzugten Ausführungsbeispiels mithilfe der einzigen Zeichnung näher erläutert, die schematisch im Schnitt eine Vakuumpumpe gemäß der Erfindung zeigt.The invention is explained in more detail below on the basis of a preferred exemplary embodiment with the aid of the single drawing, which schematically shows in section a vacuum pump according to the invention.

Das gewählte Ausführungsbeispiel betrifft eine Drehschieberpumpe mit einem Gehäuse 1 und einem rotierenden Drehschieber 2. Das Gehäuse sitzt in einer nicht dargestellten Ölwanne und besitzt einen Einlaß 3, der mit einem zu evakuierenden Gefäß verbindbar ist, und einen Auslaßkanal 4, der über eine Rückschlagklappe 5 mit der Umgebungsatmosphäre in Verbindung gebracht werden kann. Die Rückschlagklappe 5 wird durch eine Feder 6 in Schließstellung gehalten, solange der Druck im Auslaßkanal 4 den durch Atmosphärendruck und die Feder 6 erzeugten Gegendruck nicht übersteigt.The selected embodiment relates to a rotary vane pump with a housing 1 and a rotating rotary valve 2. The housing sits in an oil pan, not shown, and has an inlet 3, which can be connected to a vessel to be evacuated, and an outlet channel 4, which with a check valve 5 can be associated with the surrounding atmosphere. The check valve 5 is held in the closed position by a spring 6 as long as the pressure in the outlet channel 4 does not exceed the counter pressure generated by atmospheric pressure and the spring 6.

In Strömungsrichtung der zu pumpenden Gase vor der Rückschlagklappe 5 sitzt im Auslaßkanal 4 eine Gasstrahlpumpe, deren Strahlrichtung parallel zur Dichtfläche der Rückschlagklappe 5 verläuft. Die Pumpe besteht aus einer Injektionsdüse 7 und einem dazu fluchtenden Auffangrohr 8. Die Düse 7 ist über eine in das Gehäuse 1 der Pumpe eingearbeitete Leitung 9 an eine nicht dargestellte Druckluftquelle anschließbar, während das Auffangrohr entweder in die Außenatmosphäre mündet oder, wie es meist der Fall ist, mit einem Aufbereitungsbehälter verbunden ist, in dem aus dem zu evakuierenden Behälter stammende toxische Gase aus dem Luftstrom abgetrennt werden können. Statt Luft kann auch ein anderes, insbesondere ein inertes Gas als Treibmittel verwendet werden.In the flow direction of the gases to be pumped in front of the check valve 5, a gas jet pump is seated in the outlet channel 4, the jet direction of which runs parallel to the sealing surface of the check valve 5. The pump consists of an injection nozzle 7 and a collecting pipe 8 aligned therewith. The nozzle 7 can be connected to a compressed air source (not shown) via a line 9 incorporated into the housing 1 of the pump, while the Collecting pipe either opens into the outside atmosphere or, as is usually the case, is connected to a treatment tank in which toxic gases from the tank to be evacuated can be separated from the air flow. Instead of air, another gas, in particular an inert gas, can also be used as the blowing agent.

Die erfindungsgemäße Pumpe ist nicht vergleichbar mit der Hintereinanderschaltung einer mechanischen Vakuumpumpe und einer Treibmittelpumpe, da bei einer solchen Hintereinanderschaltung die Treibmittelpumpe hinter der Rückschlagklappe 5 sitzen würde und alle von der mechanischen Pumpe geförderten Moleküle anschließend durch die Gasstrahlpumpe abgesaugt würden. Durch die Integration der Gasstrahlpumpe in die mechanische Vakuumpumpe, und zwar in Strömungsrichtung vor der Rückschlagklappe dieser Pumpe, wird das hohe Saugvermögen der mechanischen Vakuumpumpe bei geringer Druckdifferenz zwischen Einlaß- und Auslaßkanal voll wirksam, während mit zunehmendem Vakuum der Auslaßkanal 4 vor der Rückschlagklappe durch die Gasstrahlpumpe auf einen deutlich unter Atmosphärendruck liegenden Wert gebracht wird, wodurch das zu erzielende Endvakuum im Einlaßkanal 3 um mindestens einen Faktor 10 erhöht wird.The pump according to the invention is not comparable to the series connection of a mechanical vacuum pump and a propellant pump, since in such a series connection the propellant pump would sit behind the non-return valve 5 and all the molecules conveyed by the mechanical pump would then be sucked off by the gas jet pump. By integrating the gas jet pump into the mechanical vacuum pump, namely in the direction of flow in front of the non-return valve of this pump, the high suction capacity of the mechanical vacuum pump becomes fully effective with a small pressure difference between the inlet and outlet channels, while with increasing vacuum the outlet channel 4 in front of the non-return valve through Gas jet pump is brought to a value significantly below atmospheric pressure, whereby the ultimate vacuum to be achieved in the inlet channel 3 is increased by at least a factor of 10.

Die Erfindung ist nicht im einzelnen auf das dargestellte Ausführungsbeispiel beschränkt. So kann die Gasstrahlpumpe auch in Verbindung mit einer mechanischen Vakuumpumpe eines anderen Typs wie z.B. einer Roots-Pumpe oder einer Sperrschieberpumpe verwendet werden. Auch bei ölgeschmierten mechanischen Vakuumpumpen ist die Erfindung mit Vorteil anwendbar.The invention is not restricted in detail to the exemplary embodiment shown. The gas jet pump can also be used in conjunction with a mechanical vacuum pump of another type, e.g. a Roots pump or a gate valve pump. The invention can also be used to advantage with oil-lubricated mechanical vacuum pumps.

In allen Fällen wirkt die Gasstrahlpumpe nicht nur zugunsten eines besseren Endvakuums, sondern auch als wärmeabführendes Element, so daß die Erwärmung der Pumpe verringert ist.In all cases, the gas jet pump works not only in favor of a better final vacuum, but also as a heat-dissipating element, so that the heating of the pump is reduced.

Claims (2)

  1. A mechanical pump including a casing which comprises an inlet channel on the suction side and an outlet channel on the discharge side, the latter being provided with a spring-loaded flap valve, characterized in that a gas jet pump (7, 8) is incorporated in the outlet channel (4) upstream of the flap valve (5), seen in the fluid conveyance direction.
  2. A vacuum pump according to claim 1, characterized in that the direction of the jet of the gas jet pump (7, 8) is parallel to the sealing surface of the flap valve (5).
EP88120714A 1987-06-30 1988-12-12 Mechanical vacuum pump with a spring loaded return valve Expired - Lifetime EP0373229B1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19873721611 DE3721611A1 (en) 1987-06-30 1987-06-30 MECHANICAL VACUUM PUMP WITH A SPRING-LOADED CHECK VALVE

Publications (2)

Publication Number Publication Date
EP0373229A1 EP0373229A1 (en) 1990-06-20
EP0373229B1 true EP0373229B1 (en) 1992-09-16

Family

ID=6330602

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88120714A Expired - Lifetime EP0373229B1 (en) 1987-06-30 1988-12-12 Mechanical vacuum pump with a spring loaded return valve

Country Status (3)

Country Link
US (1) US4921406A (en)
EP (1) EP0373229B1 (en)
DE (1) DE3721611A1 (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0798463A3 (en) * 1996-03-29 1998-02-25 Anest Iwata Corporation Oil-free scroll vacuum pump
GB2389875A (en) * 2002-06-21 2003-12-24 Boc Group Plc Vane pump with a non-circular bore
DE102010004657B4 (en) * 2010-01-14 2012-03-22 Knorr-Bremse Systeme für Nutzfahrzeuge GmbH Fresh gas supply device for an internal combustion engine and method for operating such a fresh gas supply device
US9039385B2 (en) 2011-11-28 2015-05-26 Ford Global Technologies, Llc Jet pump assembly
PT3137771T (en) * 2014-05-01 2020-05-29 Ateliers Busch S A Method of pumping in a pumping system and vacuum pump system
US11209024B2 (en) * 2015-06-24 2021-12-28 Itt Manufacturing Enterprises Llc Discharge casing insert for pump performance characteristics control

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1073834A (en) * 1952-04-02 1954-09-29 Daimler Benz Ag Rotary piston compressor, especially root compressor for internal combustion engines
FR1121079A (en) * 1955-02-03 1956-07-20 Volumetric turbine
DE1270215B (en) * 1962-12-07 1968-06-12 Siemen & Hinsch Gmbh Pump unit
US3556681A (en) * 1969-02-03 1971-01-19 Irving C Jennings High vacuum pump with air jet having automatic cut-in valve
DE2821814C2 (en) * 1978-05-19 1986-10-16 Daimler-Benz Ag, 7000 Stuttgart Air suction system for motor vehicles
JPS62243982A (en) * 1986-04-14 1987-10-24 Hitachi Ltd 2-stage vacuum pump and operating method thereof

Also Published As

Publication number Publication date
DE3721611A1 (en) 1989-01-19
EP0373229A1 (en) 1990-06-20
US4921406A (en) 1990-05-01
DE3721611C2 (en) 1989-04-20

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