EP3064775B1 - Vacuum pump and method for detecting a contact between at least one rotor and a stator of a vacuum pump - Google Patents

Vacuum pump and method for detecting a contact between at least one rotor and a stator of a vacuum pump Download PDF

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Publication number
EP3064775B1
EP3064775B1 EP15157105.6A EP15157105A EP3064775B1 EP 3064775 B1 EP3064775 B1 EP 3064775B1 EP 15157105 A EP15157105 A EP 15157105A EP 3064775 B1 EP3064775 B1 EP 3064775B1
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EP
European Patent Office
Prior art keywords
contact
sensor
housing
vacuum pump
piston
Prior art date
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EP15157105.6A
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German (de)
French (fr)
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EP3064775A1 (en
Inventor
Peter Huber
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Pfeiffer Vacuum GmbH
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Pfeiffer Vacuum GmbH
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Priority to EP15157105.6A priority Critical patent/EP3064775B1/en
Publication of EP3064775A1 publication Critical patent/EP3064775A1/en
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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
    • F04C25/00—Adaptations of pumps for special use of pumps for elastic fluids
    • F04C25/02—Adaptations of pumps for special use of pumps for elastic fluids for producing high vacuum
    • 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
    • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
    • F04C28/28—Safety arrangements; Monitoring
    • 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
    • F04C29/0042—Driving elements, brakes, couplings, transmissions 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
    • F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C18/12—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
    • F04C18/126—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with radially from the rotor body extending elements, not necessarily co-operating with corresponding recesses in the other rotor, e.g. lobes, Roots type
    • 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
    • F04C18/14—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 toothed rotary pistons
    • F04C18/16—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 toothed rotary pistons with helical teeth, e.g. chevron-shaped, screw type
    • 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
    • F04C2230/00—Manufacture
    • F04C2230/60—Assembly methods
    • F04C2230/602—Gap; Clearance
    • 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
    • F04C2240/00—Components
    • F04C2240/60—Shafts
    • 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
    • F04C2240/00—Components
    • F04C2240/80—Other components
    • F04C2240/81—Sensor, e.g. electronic sensor for control or monitoring

Definitions

  • the invention relates to a vacuum pump and a method for detecting a contact between at least one rotor and a stator of a vacuum pump.
  • twin-shaft vacuum pump is, for example, from DE 10 2008 060 540 A1 known.
  • Two-shaft vacuum pumps are, for example, Roots vacuum pumps or screw vacuum pumps.
  • US2012/025800A1 includes a device for monitoring the wear of pump liners.
  • This device has a wear sensor which is arranged in a housing of the pump.
  • a loop of an electrical conductor is arranged in the wear detector and the conductor is connected to a controller.
  • a controller monitors whether various circuit loops in the wear sensor are functioning.
  • This prior art device has the disadvantage of being relatively expensive and requiring separate circuitry.
  • a vacuum pump which has one or more temperature sensors which are arranged in the region of the rotor in order to be able to detect heating of the rotor.
  • a proximity sensor can also be provided.
  • a proximity sensor has the disadvantage that the gaps in the pump between the rotor and the stator must remain relatively large since a proximity sensor works with a relatively large tolerance.
  • Roots vacuum pumps and screw vacuum pumps are cooled via the surface of their housing. Heat is therefore released from the pump surface to the environment. In continuous operation and under constant conditions, an equilibrium is established for the input power and the waste heat. In this state, the various components, whose linear expansion depends on the temperature, have a constant gap size between the moving parts and the stationary parts.
  • the gaps between the piston or screw and the housing, in particular the end shield, largely determine the operational safety against so-called bumping as well as the level of the vacuum parameters such as pumping speed, compression capacity and ultimate pressure.
  • a first problem here is that due to the reduced thermal conductivity in the vacuum, rapid changes in the input variables lead to build-up between the rotor and the housing or the end shield.
  • a second problem is that the size of the gap between the pumping rotor and the stationary housing components (stator) is of particular importance for the operational reliability of these pumps. Deposits and contamination in the suction chamber make it difficult to measure the gap size directly.
  • the technical problem on which the invention is based is to specify a vacuum pump in which so-called starters can be detected at an early stage, and to specify a method for detecting a contact between at least one rotor and a stator of a vacuum pump, with which contact can also be detected at an early stage, so that the vacuum pump is protected as completely as possible from consequential damage caused by these so-called start-ups.
  • the vacuum pump according to the invention with a housing, two shafts arranged in the housing and rotatably driven via a drive and with a gear coupled to the shafts, in which between a piston arranged on the shaft or a screw arranged on the shaft and an inside of the housing or of a stator, at least one sensor and at least one stop element or at least one sensor and at least one abrasion element is arranged, is characterized in that at least one acceleration sensor or at least one vibration sensor is provided, which acts as a signal in the event of contact between the piston or the screw and the Stop element or the abrasion element is formed with an acceleration sensor or vibration sensor that detects a signal that is characteristic of the contact, and that the at least one stop element or the at least one abrasion element has a lower height than the gap height provided during normal operation between K piston or screw and inside of the housing or stator.
  • the shaft expands with the piston, or if the housing shrinks, the pistons or the screws hit the stop element, which in turn can be detected by a vibration sensor. If a sensor is arranged in the gap, the sensor will be damaged by the contact, which can be detected by an evaluation unit. If a contact is detected accordingly, the specified measures can be taken, for example additional cooling can be provided or the drive motor is braked or switched off.
  • the at least one stop element or at least an abrasion element has a lower height than the gap height provided during normal operation between the piston or screw and the inside of the housing or stator. This means that during normal operation the piston or the screw does not strike the stop element or the sensor or the wear element.
  • the vacuum pump is designed in such a way that at least one acceleration sensor or at least one vibration sensor is provided.
  • These sensors are used to detect contact between the piston or screw and the inside of the housing or stator.
  • the method according to the invention for detecting a contact between at least one rotor and a stator of a vacuum pump is characterized in that at least one acceleration sensor or at least one vibration sensor is provided which, when there is contact between the piston or the screw and the stop element or the wear element signal characteristic of the contact is detected.
  • a signal is detected by the at least one acceleration sensor and/or at least one vibration sensor. If this signal exceeds a threshold value at one or more fixed frequencies for the respective speed, this means that there is an imbalance or bearing damage or the like.
  • a further embodiment of the inventive method for detecting a contact between at least a rotor and a stator of a vacuum pump is characterized in that when the piston or the screw comes into contact with the at least one sensor, an evaluation unit detects the contact and/or the destruction of the sensor.
  • an evaluation unit which evaluates signals from the at least one acceleration sensor or from the at least one vibration sensor.
  • This evaluation unit is advantageous for detecting contact according to the various possibilities and for initiating the necessary measures to avoid consequential damage.
  • the evaluation unit triggers measures to prevent damage when it detects the beginning of contact between the rotor and stator. These measures can be, for example, braking or switching off the drive motor, rotor cooling or the like.
  • acceleration and/or vibration sensors are used to determine whether a signal exceeds a threshold value at one or more fixed frequencies for the respective rotational speed.
  • the piston and/or the screws advantageously have one or more additional elements in the area between the largest diameter of the rotor (overspeed range wiper) or also the target contour of the piston or the screw and the inside of the housing or stator. These elements can be placed in the piston or in the screw as well as in the housing or in the stator. The elements create the narrowest gap between the rotor and the housing, which disappears when the temperature balance is disturbed and, on contact, generates a percussive signal at a multiple of the rotational frequency of the rotor.
  • Another embodiment provides that a vibration sensor on the side opposite the sensor measures a particularly strong signal that clearly stands out from the background noise of the same frequency.
  • the impact frequency can be shifted to a range that is more suitable for detection.
  • Complex frequency analyzes can be dispensed with here.
  • the invention advantageously relates to double-shaft pumps. This can be Roots pumps or screw pumps.
  • the vacuum pump has a housing and that the housing is designed symmetrically in the area where the two shafts are accommodated. This symmetrical design of the housing supports and simplifies the design.
  • the transmission has gear wheels and the gear wheels are designed as gear wheels with straight teeth. If the transmission gears are straight-toothed, no axial forces occur due to the toothing. This makes it possible to work with narrow axial gaps.
  • FIG. 1 shows a section through a vacuum pump 1, the housing 2 of which essentially has two housing parts 3 and 4, namely suction chambers 3 and a gear chamber 4 provided with a lubricant reservoir 5.
  • the vacuum pump shown is a Roots vacuum pump.
  • Two shafts 6 and 7 are mounted in the housing 2 so as to be horizontally rotatable via roller bearings 8 .
  • the shaft 6 is driven by a drive (not shown), for example an asynchronous motor.
  • the asynchronous motor acts on a clutch 9.
  • a gear 11 is arranged as part of a gear 10 in the gear chamber 4 the shaft 7 mounted second gear 12 is engaged.
  • the housing part 4 having the transmission 10 can be closed off from the environment via a transmission cover 13 which can be fixed to the rest of the housing 2 .
  • Pistons 14 and 15 are arranged on the parts of the shafts 6 and 7 that pass through the suction chambers 3, which cause the pumping effect when the shafts 6 and 7 rotate and suck fluid into the suction chambers 3 via at least one suction opening (not shown) and via at least one Discharge opening (not shown) discharge from the suction chambers 3 again.
  • the pistons 14, 15 are designed as double-arched rotors.
  • the cross-sectional shape of the pistons 14, 15 is approximately in the shape of the figure "8".
  • the pistons 14, 15 are arranged in a rotor chamber formed by the housing part 3 with a minimum distance between a peripheral surface of the housing part 3 and the pistons 14, 15. Furthermore, when the pistons 14, 15 are engaged with each other, they have formed a minimum distance between them to prevent them from directly engaging or interfering with each other.
  • the drive shaft 6 is rotated by the drive, for example an electric motor. Thereby, the output shaft 7 is rotated in the opposite direction to the drive shaft 6 by the meshing relationship between a drive gear 11 and a driven gear 12, and the drive rotor with pistons 15 and the driven rotor with pistons 14 are rotated accordingly.
  • both the gears 11 and 12 and the rolling bearings 8 must be supplied with a lubricant in order to cool them and to avoid increased wear.
  • the gear chamber 4 has a lubricant reservoir 5 filled with a lubricant.
  • a centrifugal disc 16 arranged on the shaft 6 dips into the lubricant reservoir 5 and distributes the lubricant throughout the entire gear chamber 4 and in particular feeds it to the roller bearings 8 and the gear wheels 11 and 12 .
  • FIG. 2 shows an abrasion element 31 which is arranged in a housing 2 on a housing inner side 32 .
  • the piston 14 also has a further wear element 33 .
  • the wear elements 31, 33 come into contact and generate an impact signal which is detected by a vibration sensor (not shown).
  • the abrasion element 31 in which, for example, a wire 34 can be arranged.
  • the abrasion element 31 consists of a base body 35, which consists for example of plastic or ceramic.
  • the wire 34 is embedded in the base body 35 . If the base body 35 is sheared off upon contact between the abrasion element 33 and the abrasion element 31, an electrical contact that was established by the wire 34 is interrupted. This interruption is detected by an evaluation unit (not shown) and suitable measures can be taken, for example a drive motor is slowed down or switched off.
  • FIG. 4 shows the piston 14, which is arranged on the shaft 6.
  • An abrasion element 31 is arranged in the housing 2 on the housing inner wall 32 .
  • a signal is detected with an acceleration and/or vibration sensor. If the signal exceeds a threshold at one or more fixed frequencies for that speed, this is an indication that contact is occurring. In this case, the drive motor can be switched off. This avoids a so-called collision between the piston 14 and the inner wall 32 of the housing, which would damage the vacuum pump.
  • FIG. 5 shows a modified embodiment in which the piston 14 carries a wear element 31.
  • FIG. In this case, the housing 2 with the housing inside 32 has no additional element.
  • abrasion element 31 As in 6 shown to form the abrasion element 31 as a sensor, such as in figure 5 shown.
  • an abrasion element 33 can be arranged on the pistons 14 .
  • the wear element can be cuboid, as in FIG 8 shown.
  • the abrasion element 33 can have rounded edges, as in FIG 9 shown.
  • the abrasion element 33 can also be cylindrical, as in 10 shown.
  • the housing 2 has an inlet 39 and an outlet 40 .
  • the 12 and 13 show the wear element 33, which is arranged, for example, on the piston 14.
  • the abrasion element 33 has a small contact surface 41 . Due to the fact that the possible contact surface 41 with the housing 2 is very small, this leads to minimal friction and low waste heat for contact detection in the event of contact. The main focus here is detection and not improved damage tolerance.

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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 betrifft eine Vakuumpumpe sowie ein Verfahren zur Detektion eines Kontaktes zwischen wenigstens einem Rotor und einem Stator einer Vakuumpumpe.The invention relates to a vacuum pump and a method for detecting a contact between at least one rotor and a stator of a vacuum pump.

Die Entwicklung der Vakuumpumpen geht hin zu Vakuumpumpen mit einer hoher Leistungsdichte und einem kompakten Pumpengehäuse. Überschreitet die Leistungsdichte ein gewisses Maß, kann durch freie Konvektion keine gleichmäßige Temperaturverteilung über die verschiedenen Bauteile mehr gewährleistet werden. Bei einer Wärmedehnung und/oder ungleichmäßigen Temperaturverteilung kommt es bei den relativ engen Spalten, die üblicherweise zwischen einem hundertstel Millimeter bis einem Millimeter liegen, zwischen den relativ zueinander bewegten Bauteilen zu einem Anlaufen der Teile untereinander, das heißt zu einem Kontakt zwischen den Teilen mit möglichen Folgeschäden für das gesamte System.The development of vacuum pumps is moving towards vacuum pumps with a high power density and a compact pump housing. If the power density exceeds a certain level, free convection can no longer guarantee an even temperature distribution across the various components. In the case of thermal expansion and/or uneven temperature distribution, the relatively narrow gaps, which are usually between a hundredth of a millimeter and one millimeter, between the components that are moving relative to one another lead to the parts rubbing against each other, i.e. there is contact between the parts with possible consequential damage for the entire system.

Die Erfindung bezieht sich auf zweiwellige Vakuumpumpen. Eine zweiwellige Vakuumpumpe ist beispielsweise aus der DE 10 2008 060 540 A1 bekannt. Zweiwellige Vakuumpumpen sind beispielsweise Wälzkolbenvakuumpumpen oder Schraubenvakuumpumpen.The invention relates to twin-shaft vacuum pumps. A twin-shaft vacuum pump is, for example, from DE 10 2008 060 540 A1 known. Two-shaft vacuum pumps are, for example, Roots vacuum pumps or screw vacuum pumps.

Zum Stand der Technik ( US 2012/025800 A1 ) gehört eine Vorrichtung zur Überwachung der Abnutzung von Pumpenauskleidungen. Diese Vorrichtung weist einen Verschleißsensor auf, der in einem Gehäuse der Pumpe angeordnet ist. In dem Verschleißdetektor ist eine Schleife eines elektrischen Leiters angeordnet und der Leiter ist mit einer Steuerung verbunden. Ein Controller überwacht, ob verschiedene Schaltkreisschleifen in dem Verschleißsensor funktionieren.On the state of the art ( US2012/025800A1 ) includes a device for monitoring the wear of pump liners. This device has a wear sensor which is arranged in a housing of the pump. A loop of an electrical conductor is arranged in the wear detector and the conductor is connected to a controller. A controller monitors whether various circuit loops in the wear sensor are functioning.

Diese zum Stand der Technik gehörende Vorrichtung weist den Nachteil auf, dass sie relativ aufwendig ist und ein gesonderter Schaltkreis erforderlich ist.This prior art device has the disadvantage of being relatively expensive and requiring separate circuitry.

Weiterhin gehört zum Stand der Technik ( FR 2 812 041 A1 ) eine Vakuumpumpe, welche einen oder mehrere Temperatursensoren aufweist, die im Bereich des Rotors angeordnet sind, um eine Erwärmung des Rotors erfassen zu können. Gemäß diesem Stand der Technik kann auch ein Näherungssensor vorgesehen sein.Furthermore belongs to the state of the art ( FR 2 812 041 A1 ) a vacuum pump which has one or more temperature sensors which are arranged in the region of the rotor in order to be able to detect heating of the rotor. According to this prior art, a proximity sensor can also be provided.

Das Vorsehen eines Näherungssensors weist den Nachteil auf, dass die Spalte in der Pumpe zwischen Rotor und Stator relativ groß bleiben müssen, da ein Näherungssensor mit einer relativ großen Toleranz arbeitet.The provision of a proximity sensor has the disadvantage that the gaps in the pump between the rotor and the stator must remain relatively large since a proximity sensor works with a relatively large tolerance.

Die Gehäuse von Wälzkolbenvakuumpumpen und Schraubenvakuumpumpen werden über die Oberfläche ihrer Gehäuse gekühlt. Wärme wird also von der Pumpenoberfläche an die Umgebung abgegeben. Im kontinuierlichen Betrieb und für konstante Bedingungen stellt sich ein Gleichgewicht für die eingebrachte Leistung und die Abwärme ein. Die verschiedenen.Komponenten, deren Längenausdehnung von der Temperatur abhängt, weisen in diesem Zustand eine gleichbleibende Spaltgröße zwischen den beweglichen Teilen und den stehenden Teilen auf. Die Spalte zwischen Kolben oder Schraube und Gehäuse, insbesondere Lagerschild, bestimmen dabei maßgeblich die Betriebssicherheit gegen so genannte Anläufer als auch die Höhe der Vakuumkennwerte wie Saugvermögen, Kompressionsvermögen und Enddruck.The housings of Roots vacuum pumps and screw vacuum pumps are cooled via the surface of their housing. Heat is therefore released from the pump surface to the environment. In continuous operation and under constant conditions, an equilibrium is established for the input power and the waste heat. In this state, the various components, whose linear expansion depends on the temperature, have a constant gap size between the moving parts and the stationary parts. The gaps between the piston or screw and the housing, in particular the end shield, largely determine the operational safety against so-called bumping as well as the level of the vacuum parameters such as pumping speed, compression capacity and ultimate pressure.

Ein erstes Problem ist hierbei, dass wegen der verringerten Wärmeleitfähigkeit im Vakuum schnelle Änderungen der Eingangsgrößen zu Anläufern zwischen Rotor und Gehäuse beziehungsweise Lagerschild führen.A first problem here is that due to the reduced thermal conductivity in the vacuum, rapid changes in the input variables lead to build-up between the rotor and the housing or the end shield.

Ein zweites Problem ist, dass die Spaltgröße zwischen pumpwirksamem Rotor und unbewegten Gehäusebauteilen (Stator) von besonderer Bedeutung für die Betriebssicherheit dieser Pumpen ist. Ablagerungen und Verunreinigungen im Schöpfraum erschweren die direkte Messung der Spaltgröße.A second problem is that the size of the gap between the pumping rotor and the stationary housing components (stator) is of particular importance for the operational reliability of these pumps. Deposits and contamination in the suction chamber make it difficult to measure the gap size directly.

Das der Erfindung zugrunde liegende technische Problem besteht darin, eine Vakuumpumpe anzugeben, bei der frühzeitig sogenannte Anläufer detektierbar sind, sowie ein Verfahren zur Detektion eines Kontaktes zwischen wenigstens einem Rotor und einem Stator einer Vakuumpumpe anzugeben, mit dem ebenfalls frühzeitig ein Kontakt detektiert werden kann, damit die Vakuumpumpe möglichst vollständig vor Folgeschäden dieser sogenannten Anläufer geschützt wird.The technical problem on which the invention is based is to specify a vacuum pump in which so-called starters can be detected at an early stage, and to specify a method for detecting a contact between at least one rotor and a stator of a vacuum pump, with which contact can also be detected at an early stage, so that the vacuum pump is protected as completely as possible from consequential damage caused by these so-called start-ups.

Dieses technische Problem wird durch eine Vakuumpumpe mit den Merkmalen gemäß Anspruch 1 sowie durch ein Verfahren mit den Merkmalen gemäß Anspruch 2 gelöst.This technical problem is solved by a vacuum pump having the features of claim 1 and by a method having the features of claim 2.

Die erfindungsgemäße Vakuumpumpe mit einem Gehäuse, zwei in dem Gehäuse angeordneten, über einen Antrieb drehbar angetriebenen Wellen sowie mit einem mit den Wellen gekoppelten Getriebe, bei der zwischen einem auf der Welle angeordneten Kolben oder einer auf der Welle angeordneten Schraube und einer Innenseite des Gehäuses oder eines Stators wenigstens ein Sensor und wenigstens ein Anschlagelement oder wenigstens ein Sensor und wenigstens ein Abriebselement angeordnet ist, zeichnet sich dadurch aus, dass wenigstens ein Beschleunigungssensor oder wenigstens ein Schwingungssensor vorgesehen ist, der als ein bei einem Kontakt zwischen dem Kolben oder der Schraube und dem Anschlagelement oder dem Abriebselement ein für den Kontakt charakteristisches Signal erfassender Beschleunigungssensor oder Schwingungssensor ausgebildet ist, und dass das wenigstens eine Anschlagelement oder das wenigstens eine Abriebselement eine geringere Höhe als die bei Normalbetrieb vorgesehene Spalthöhe zwischen Kolben oder Schraube und Innenseite des Gehäuses oder Stators aufweist.The vacuum pump according to the invention with a housing, two shafts arranged in the housing and rotatably driven via a drive and with a gear coupled to the shafts, in which between a piston arranged on the shaft or a screw arranged on the shaft and an inside of the housing or of a stator, at least one sensor and at least one stop element or at least one sensor and at least one abrasion element is arranged, is characterized in that at least one acceleration sensor or at least one vibration sensor is provided, which acts as a signal in the event of contact between the piston or the screw and the Stop element or the abrasion element is formed with an acceleration sensor or vibration sensor that detects a signal that is characteristic of the contact, and that the at least one stop element or the at least one abrasion element has a lower height than the gap height provided during normal operation between K piston or screw and inside of the housing or stator.

Dehnt sich die Welle mit dem Kolben aus, oder schrumpft das Gehäuse, schlagen die Kolben oder die Schrauben an dem Anschlagelement an, was wiederum von einem Schwingungssensor detektierbar ist. Ist ein Sensor in dem Spalt angeordnet, wird der Sensor durch den Kontakt beschädigt, was von einer Auswerteeinheit erfasst werden kann. Wird ein Kontakt entsprechend detektiert, können die vorgegebenen Maßnahmen ergriffen werden, beispielsweise kann eine zusätzliche Kühlung vorgesehen sein oder der Antriebsmotor wird abgebremst oder ausgeschaltet.If the shaft expands with the piston, or if the housing shrinks, the pistons or the screws hit the stop element, which in turn can be detected by a vibration sensor. If a sensor is arranged in the gap, the sensor will be damaged by the contact, which can be detected by an evaluation unit. If a contact is detected accordingly, the specified measures can be taken, for example additional cooling can be provided or the drive motor is braked or switched off.

Ist ein Sensor vorgesehen, der zerstört oder beschädigt wird, wird der Sensor ausgetauscht. Auch hierbei handelt es sich um ein Verschleißteil, welches jedoch wesentlich günstiger ist, als wenn ein Schaden bei einem sogenannten Anläufer in der Pumpe auftritt.If a sensor is provided that is destroyed or damaged, the sensor will be replaced. This is also a wearing part, which is much cheaper than if damage occurs with a so-called starter in the pump.

Gemäß der Erfindung ist vorgesehen, dass das wenigstens eine Anschlagelement oder wenigstens eine Abriebselement eine geringere Höhe als die bei Normalbetrieb vorgesehene Spalthöhe zwischen Kolben oder Schraube und Innenseite des Gehäuses oder Stators aufweist. Das bedeutet, dass im Normalbetrieb ein Anschlag des Kolbens oder der Schraube an dem Anschlagelement oder dem Sensor oder dem Abriebselement nicht erfolgt.According to the invention it is provided that the at least one stop element or at least an abrasion element has a lower height than the gap height provided during normal operation between the piston or screw and the inside of the housing or stator. This means that during normal operation the piston or the screw does not strike the stop element or the sensor or the wear element.

Gemäß der Erfindung ist die Vakuumpumpe derart ausgebildet, dass wenigstens ein Beschleunigungssensor oder wenigstens ein Schwingungssensor vorgesehen ist.According to the invention, the vacuum pump is designed in such a way that at least one acceleration sensor or at least one vibration sensor is provided.

Diese Sensoren dienen dazu, einen Kontakt zwischen Kolben oder Schraube und Innenseite des Gehäuses oder Stator zu detektieren.These sensors are used to detect contact between the piston or screw and the inside of the housing or stator.

Das erfindungsgemäße Verfahren zur Detektion eines Kontaktes zwischen wenigstens einem Rotor und einem Stator einer Vakuumpumpe zeichnet sich dadurch aus, dass wenigstens ein Beschleunigungs- oder wenigstens ein Schwingungssensor vorgesehen ist, der bei einem Kontakt zwischen dem Kolben oder der Schraube und dem Anschlagelement oder dem Abriebselement ein für den Kontakt charakteristisches Signal erfasst.The method according to the invention for detecting a contact between at least one rotor and a stator of a vacuum pump is characterized in that at least one acceleration sensor or at least one vibration sensor is provided which, when there is contact between the piston or the screw and the stop element or the wear element signal characteristic of the contact is detected.

Bei einem Kontakt wird von dem wenigstens einen Beschleunigungs- und/oder wenigstens einen Schwingungssensor ein Signal erfasst. Übersteigt dieses Signal einen Schwellwert bei einer oder mehreren festen Frequenzen für die jeweilige Drehzahl, bedeutet dies, dass eine Unwucht oder ein Lagerschaden oder dergleichen vorliegt.In the event of contact, a signal is detected by the at least one acceleration sensor and/or at least one vibration sensor. If this signal exceeds a threshold value at one or more fixed frequencies for the respective speed, this means that there is an imbalance or bearing damage or the like.

Eine weitere Ausführungsform des erfindungsgemäßen Verfahrens zur Detektion eines Kontaktes zwischen wenigstens einem Rotor und einem Stator einer Vakuumpumpe zeichnet sich dadurch aus, dass bei einem Kontakt des Kolbens oder der Schraube mit dem wenigstens einen Sensor eine Auswerteeinheit den Kontakt und/oder das Zerstören des Sensors detektiert.A further embodiment of the inventive method for detecting a contact between at least a rotor and a stator of a vacuum pump is characterized in that when the piston or the screw comes into contact with the at least one sensor, an evaluation unit detects the contact and/or the destruction of the sensor.

Dehnt sich der Kolben und/oder die Schraube entsprechend aus, wird ein Kontakt mit dem Sensor hergestellt, wobei dieser beispielsweise abgeschert wird. Eine Auswerteeinheit erfasst das Zerstören des Sensors und kann die schon beschriebenen erforderlichen Maßnahmen veranlassen.If the piston and/or the screw expands accordingly, contact is made with the sensor, which is sheared off, for example. An evaluation unit detects the destruction of the sensor and can initiate the necessary measures already described.

Gemäß einer weiteren vorteilhaften Ausführungsform der Erfindung ist eine Auswerteeinheit vorgesehen, die Signale des wenigstens einen Beschleunigungssensors oder des wenigstens einen Schwingungssensors auswertet. Diese Auswerteeinheit ist vorteilhaft, um einen Kontakt entsprechend den verschiedenen Möglichkeiten zu detektieren und die erforderlichen Maßnahmen zur Vermeidung von Folgeschäden einzuleiten.According to a further advantageous embodiment of the invention, an evaluation unit is provided which evaluates signals from the at least one acceleration sensor or from the at least one vibration sensor. This evaluation unit is advantageous for detecting contact according to the various possibilities and for initiating the necessary measures to avoid consequential damage.

Gemäß einer besonders bevorzugten Ausführungsform der Erfindung ist vorgesehen, dass die Auswerteeinheit bei Feststellen eines beginnenden Kontaktes zwischen Rotor und Stator Maßnahmen zur Vermeidung von Schäden auslöst. Diese Maßnahmen können beispielsweise sein das Abbremsen oder Ausschalten des Antriebsmotors, eine Rotorkühlung oder dergleichen.According to a particularly preferred embodiment of the invention, it is provided that the evaluation unit triggers measures to prevent damage when it detects the beginning of contact between the rotor and stator. These measures can be, for example, braking or switching off the drive motor, rotor cooling or the like.

Gemäß einer vorteilhaften Ausführungsform der Erfindung wird bei der Detektion eines Kontaktes über Beschleunigungs- und/oder Schwingungssensoren ermittelt, ob ein Signal einen Schwellwert bei einer oder mehreren festen Frequenzen für die jeweilige Drehzahl übersteigt. Hierbei weist der Kolben und/oder die Schrauben vorteilhaft im Bereich zwischen dem größten Durchmesser des Rotors (Überdrehbereichsabstreifer) oder auch Sollkontur des Kolbens oder der Schraube und der Innenseite des Gehäuses oder Stators ein oder mehrere zusätzliche Elemente auf. Diese Elemente können sowohl in den Kolben oder in die Schraube als auch in das Gehäuse oder in den Stator eingebracht werden. Die Elemente erzeugen den engsten Spalt zwischen Rotor und Gehäuse, der bei Störungen des Temperaturgleichgewichtes schwindet und bei Kontakt ein schlagendes Signal mit einem Vielfachen der Drehfrequenz des Rotors erzeugt.According to an advantageous embodiment of the invention, when a contact is detected, acceleration and/or vibration sensors are used to determine whether a signal exceeds a threshold value at one or more fixed frequencies for the respective rotational speed. Here, the piston and/or the screws advantageously have one or more additional elements in the area between the largest diameter of the rotor (overspeed range wiper) or also the target contour of the piston or the screw and the inside of the housing or stator. These elements can be placed in the piston or in the screw as well as in the housing or in the stator. The elements create the narrowest gap between the rotor and the housing, which disappears when the temperature balance is disturbed and, on contact, generates a percussive signal at a multiple of the rotational frequency of the rotor.

Eine andere Ausführungsform sieht vor, dass ein Schwingungssensor auf der dem Sensor gegenüberliegenden Seite ein besonders starkes Signal misst, das sich deutlich vom Hintergrundrauschen gleicher Frequenz abhebt.Another embodiment provides that a vibration sensor on the side opposite the sensor measures a particularly strong signal that clearly stands out from the background noise of the same frequency.

Ist eine angepasste Anzahl der schlagenden Elemente auf Seite des Rotors oder auch des Gehäuses vorgesehen, kann die Schlagfrequenz in einen für die Detektion besser geeigneten Bereich verschoben werden. Hierbei kann auf aufwendige Frequenzanalysen verzichtet werden.If an adjusted number of impacting elements is provided on the rotor or housing side, the impact frequency can be shifted to a range that is more suitable for detection. Complex frequency analyzes can be dispensed with here.

Die Erfindung bezieht sich vorteilhaft auf zweiwellige Pumpen. Es kann sich hierbei um Wälzkolbenpumpen oder Schraubenpumpen handeln.The invention advantageously relates to double-shaft pumps. This can be Roots pumps or screw pumps.

Gemäß einer weiteren vorteilhaften Ausführungsform der Erfindung ist vorgesehen, dass die Vakuumpumpe ein Gehäuse aufweist, und dass das Gehäuse im Bereich der Aufnahme der zwei Wellen symmetrisch ausgebildet ist. Diese symmetrische Ausbildung des Gehäuses unterstützt und vereinfacht die Auslegung.According to a further advantageous embodiment of the invention, it is provided that the vacuum pump has a housing and that the housing is designed symmetrically in the area where the two shafts are accommodated. This symmetrical design of the housing supports and simplifies the design.

Vorteilhaft weist das Getriebe Getriebezahnräder auf und die Getriebezahnräder sind als Zahnräder mit einer Geradverzahnung ausgebildet. Bei einer Geradverzahnung der Getriebezahnräder treten keine axialen Kräfte durch die Verzahnung auf. Hierdurch ist es möglich, mit engen axialen Spalten zu arbeiten.Advantageously, the transmission has gear wheels and the gear wheels are designed as gear wheels with straight teeth. If the transmission gears are straight-toothed, no axial forces occur due to the toothing. This makes it possible to work with narrow axial gaps.

Weitere Merkmale und Vorteile der Erfindung ergeben sich anhand der zugehörigen Zeichnungen, in denen verschiedene Ausführungsformen einer erfindungsgemäßen Vakuumpumpe nur beispielhaft dargestellt sind, ohne die Erfindung auf diese Ausführungsbeispiele zu beschränken. In den Zeichnungen zeigen:

Fig. 1
einen schematischen Längsschnitt durch eine Vakuumpumpe mit zwei Wellen;
Fig. 2
einen Querschnitt durch einen Kolben mit einem Abriebselement;
Fig. 3
einen Querschnitt durch einen zum Stand der Technik gehörenden Sensor;
Fig. 4
einen Teilquerschnitt durch einen Rotor einer Wälzkolbenpumpe mit einem am Gehäuse angeordneten Abriebselement;
Fig. 5
ein geändertes Ausführungsbeispiel;
Fig. 6
ein geändertes Ausführungsbeispiel;
Fig. 7
ein geändertes Ausführungsbeispiel;
Fig. 8
ein Abriebselement in perspektivischer Ansicht;
Fig. 9
ein Abriebselement in perspektivischer Ansicht;
Fig. 10
ein Abriebselement in perspektivischer Ansicht;
Fig. 11
einen Querschnitt durch einen Schöpfraum einer Wälzkolbenvakuumpumpe;
Fig. 12
ein geändertes Ausführungsbeispiel eines Abriebselementes in Draufsicht;
Fig. 13
das Abriebselement gemäß Fig. 12 im Querschnitt.
Further features and advantages of the invention result from the associated drawings, in which various embodiments of a vacuum pump according to the invention are shown only by way of example, without restricting the invention to these exemplary embodiments. In the drawings show:
1
a schematic longitudinal section through a vacuum pump with two shafts;
2
a cross section through a piston with an abrasion element;
3
a cross-section through a sensor belonging to the prior art;
4
a partial cross section through a rotor of a Roots pump with an abrasion element arranged on the housing;
figure 5
a modified embodiment;
6
a modified embodiment;
7
a modified embodiment;
8
a wear element in perspective view;
9
a wear element in perspective view;
10
a wear element in perspective view;
11
a cross section through a suction chamber of a Roots vacuum pump;
12
a modified embodiment of a wear element in plan view;
13
the wear element according to 12 in cross section.

Fig. 1 zeigt im Schnitt eine Vakuumpumpe 1, deren Gehäuse 2 im Wesentlichen zwei Gehäuseteile 3 und 4 aufweist, nämlich Schöpfräume 3 und einen mit einem Schmiermittelspeicher 5 versehenen Getrieberaum 4. 1 shows a section through a vacuum pump 1, the housing 2 of which essentially has two housing parts 3 and 4, namely suction chambers 3 and a gear chamber 4 provided with a lubricant reservoir 5.

Die in Fig. 1 dargestellte Vakuumpumpe ist eine Wälzkolbenvakuumpumpe.In the 1 The vacuum pump shown is a Roots vacuum pump.

Im Gehäuse 2 sind zwei Wellen 6 und 7 über Wälzlager 8 horizontal drehbar gelagert angeordnet. Die Welle 6 wird über einen Antrieb (nicht dargestellt), beispielsweise einen Asynchronmotor, angetrieben. Der nicht dargestellte Asynchronmotor wirkt auf eine Kupplung 9. Auf der vom nicht dargestellten Antrieb über die Kupplung 9 angetriebenen Welle 6 ist als Bestandteil eines Getriebes 10 im Getrieberaum 4 ein Zahnrad 11 angeordnet, das bei der dargestellten Ausführungsform einer Zweiwellen-Vakuumpumpe 1 mit einem auf der Welle 7 gelagerten zweiten Zahnrad 12 in Eingriff steht.Two shafts 6 and 7 are mounted in the housing 2 so as to be horizontally rotatable via roller bearings 8 . The shaft 6 is driven by a drive (not shown), for example an asynchronous motor. The asynchronous motor, not shown, acts on a clutch 9. On the shaft 6 driven by the drive, not shown, via the clutch 9, a gear 11 is arranged as part of a gear 10 in the gear chamber 4 the shaft 7 mounted second gear 12 is engaged.

Wie weiterhin aus Fig. 1 ersichtlich, ist der das Getriebe 10 aufweisende Gehäuseteil 4 über einen am übrigen Gehäuse 2 festlegbaren Getriebedeckel 13 gegenüber der Umgebung verschließbar.How to continue 1 As can be seen, the housing part 4 having the transmission 10 can be closed off from the environment via a transmission cover 13 which can be fixed to the rest of the housing 2 .

Auf den die Schöpfräume 3 durchsetzenden Teilen der Wellen 6 und 7 sind Kolben 14 und 15 angeordnet, die bei der Drehung der Wellen 6 und 7 den Pumpeffekt bewirken und über mindestens eine Ansaugöffnung (nicht dargestellt) Fluid in die Schöpfräume 3 ansaugen und über mindestens eine Ausstoßöffnung (nicht dargestellt) wieder aus den Schöpfräumen 3 austragen.Pistons 14 and 15 are arranged on the parts of the shafts 6 and 7 that pass through the suction chambers 3, which cause the pumping effect when the shafts 6 and 7 rotate and suck fluid into the suction chambers 3 via at least one suction opening (not shown) and via at least one Discharge opening (not shown) discharge from the suction chambers 3 again.

Die Kolben 14, 15 sind als zweibogige Rotoren ausgebildet.The pistons 14, 15 are designed as double-arched rotors.

Die Querschnittsform der Kolben 14, 15 hat annähernd die Form der Ziffer "8".The cross-sectional shape of the pistons 14, 15 is approximately in the shape of the figure "8".

Die Kolben 14, 15 sind in einer durch das Gehäuseteil 3 gebildeten Rotorkammer angeordnet mit einem minimalen Abstand zwischen einer Umfangsfläche des Gehäuseteiles 3 und den Kolben 14, 15. Darüber hinaus haben die Kolben 14, 15, wenn sie miteinander eingreifen, einen minimalen Abstand zwischen sich ausgebildet, um zu verhindern, dass sie direkt miteinander eingreifen, beziehungsweise sich behindern. Bei dem Betrieb der Wälzkolbenvakuumpumpe 1 wird die Antriebswelle 6 durch den Antrieb, beispielsweise einen Elektromotor, gedreht. Hierdurch wird die Abtriebswelle 7 in Gegenrichtung zu der Antriebswelle 6 durch die Eingreifbeziehung zwischen einem Antriebszahnrad 11 und einem Abtriebszahnrad 12 gedreht und der Antriebsrotor mit Kolben 15 und der Abtriebsrotor mit Kolben 14 werden demzufolge gedreht.The pistons 14, 15 are arranged in a rotor chamber formed by the housing part 3 with a minimum distance between a peripheral surface of the housing part 3 and the pistons 14, 15. Furthermore, when the pistons 14, 15 are engaged with each other, they have formed a minimum distance between them to prevent them from directly engaging or interfering with each other. When the Roots vacuum pump 1 is in operation, the drive shaft 6 is rotated by the drive, for example an electric motor. Thereby, the output shaft 7 is rotated in the opposite direction to the drive shaft 6 by the meshing relationship between a drive gear 11 and a driven gear 12, and the drive rotor with pistons 15 and the driven rotor with pistons 14 are rotated accordingly.

Sowohl die Zahnräder 11 und 12 als auch die Wälzlager 8 müssen mit einem Schmiermittel versorgt werden, um diese zu kühlen und einen erhöhten Verschleiß zu vermeiden. Zu diesem Zweck weist der Getrieberaum 4 einen mit einem Schmiermittel befüllten Schmiermittelspeicher 5 auf. In den Schmiermittelspeicher 5 taucht eine auf der Welle 6 angeordnete Schleuderscheibe 16 ein, die das Schmiermittel in dem gesamten Getrieberaum 4 verteilt und insbesondere den Wälzlagern 8 und den Zahnrädern 11 und 12 zuführt.Both the gears 11 and 12 and the rolling bearings 8 must be supplied with a lubricant in order to cool them and to avoid increased wear. For this purpose, the gear chamber 4 has a lubricant reservoir 5 filled with a lubricant. A centrifugal disc 16 arranged on the shaft 6 dips into the lubricant reservoir 5 and distributes the lubricant throughout the entire gear chamber 4 and in particular feeds it to the roller bearings 8 and the gear wheels 11 and 12 .

Fig. 2 zeigt ein Abriebselement 31, welches in einem Gehäuse 2 an einer Gehäuseinnenseite 32 angeordnet ist. Der Kolben 14 weist zusätzlich ein weiteres Abriebselement 33 auf. Dehnt sich der Kolben 14 in radialer Richtung aus, gelangen die Abriebselemente 31, 33 in Kontakt und erzeugen ein Schlagsignal, welches von einem Schwingungssensor (nicht dargestellt) erfasst wird. 2 shows an abrasion element 31 which is arranged in a housing 2 on a housing inner side 32 . The piston 14 also has a further wear element 33 . When the piston 14 expands in the radial direction, the wear elements 31, 33 come into contact and generate an impact signal which is detected by a vibration sensor (not shown).

Fig. 3 zeigt das Abriebselement 31, in dem beispielsweise ein Draht 34 angeordnet sein kann. Das Abriebselement 31 besteht aus einem Grundkörper 35, der beispielsweise aus Kunststoff oder Keramik besteht. Der Draht 34 ist in dem Grundkörper 35 eingebettet. Wird bei Kontakt zwischen dem Abriebselement 33 und dem Abriebselement 31 der Grundkörper 35 abgeschert, wird ein elektrischer Kontakt, der durch den Draht 34 hergestellt wurde, unterbrochen. Diese Unterbrechung wird von einer Auswerteeinheit (nicht dargestellt) erfasst und es können geeignete Maßnahmen ergriffen werden, beispielsweise wird ein Antriebsmotor verlangsamt oder abgestellt. 3 shows the abrasion element 31, in which, for example, a wire 34 can be arranged. The abrasion element 31 consists of a base body 35, which consists for example of plastic or ceramic. The wire 34 is embedded in the base body 35 . If the base body 35 is sheared off upon contact between the abrasion element 33 and the abrasion element 31, an electrical contact that was established by the wire 34 is interrupted. This interruption is detected by an evaluation unit (not shown) and suitable measures can be taken, for example a drive motor is slowed down or switched off.

Fig. 4 zeigt den Kolben 14, der auf der Welle 6 angeordnet ist. In dem Gehäuse 2 ist an der Gehäuseinnenwand 32 ein Abriebselement 31 angeordnet. 4 shows the piston 14, which is arranged on the shaft 6. An abrasion element 31 is arranged in the housing 2 on the housing inner wall 32 .

Bei Kontakt des Kolbens 14 mit dem Abriebselement 31 wird ein Signal mit einem Beschleunigungs- und/oder Schwingungssensor detektiert. Übersteigt das Signal einen Schwellwert bei einer oder mehreren festen Frequenzen für die jeweilige Drehzahl, ist dies ein Zeichen dafür, dass ein Kontakt auftritt. Der Antriebsmotor kann in diesem Fall abgestellt werden. Damit wird vermieden, dass es zu einem sogenannten Anläufer zwischen Kolben 14 und Gehäuseinnenwand 32 kommt und die Vakuumpumpe Schaden nimmt.When the piston 14 comes into contact with the wear element 31, a signal is detected with an acceleration and/or vibration sensor. If the signal exceeds a threshold at one or more fixed frequencies for that speed, this is an indication that contact is occurring. In this case, the drive motor can be switched off. This avoids a so-called collision between the piston 14 and the inner wall 32 of the housing, which would damage the vacuum pump.

Fig. 5 zeigt ein geändertes Ausführungsbeispiel, bei dem der Kolben 14 ein Abriebselement 31 trägt. In diesem Fall weist das Gehäuse 2 mit der Gehäuseinnenseite 32 kein zusätzliches Element auf. figure 5 shows a modified embodiment in which the piston 14 carries a wear element 31. FIG. In this case, the housing 2 with the housing inside 32 has no additional element.

Es besteht auch die Möglichkeit, wie in Fig. 6 dargestellt, das Abriebselement 31 als Sensor auszubilden, wie beispielsweise in Fig. 5 dargestellt. Zusätzlich kann ein Abriebselement 33 an den Kolben 14 angeordnet sein. Es besteht auch die Möglichkeit, das Abriebselement 31 als einfaches Abriebselement ohne Ausbildung als Sensor auszugestalten.There is also the possibility, as in 6 shown to form the abrasion element 31 as a sensor, such as in figure 5 shown. In addition, an abrasion element 33 can be arranged on the pistons 14 . There is also the possibility of configuring the abrasion element 31 as a simple abrasion element without being designed as a sensor.

Fig. 7 zeigt den Kolben 14 mit dem Abriebselement 33. Das Abriebselement kann quaderförmig ausgebildet sein, wie in Fig. 8 dargestellt. Das Abriebselement 33 kann abgerundete Kanten aufweisen, wie in Fig. 9 dargestellt. Das Abriebselement 33 kann auch zylinderförmig ausgebildet sein, wie in Fig. 10 dargestellt. 7 shows the piston 14 with the wear element 33. The wear element can be cuboid, as in FIG 8 shown. The abrasion element 33 can have rounded edges, as in FIG 9 shown. The abrasion element 33 can also be cylindrical, as in 10 shown.

Fig. 11 zeigt zwei Kolben 14, 15, die auf Wellen 6, 7 gelagert sind und in dem Gehäuse 2 angeordnet sind. An einer Gehäuseinnenwand 32 sind mehrere Abriebselemente 31 angeordnet. Mit einer angepassten Anzahl der Abriebselemente 31 auf der Seite des Gehäuses 2, wie in Fig. 11 dargestellt, kann die Schlagfrequenz in einen für die Detektion guten Bereich verschoben werden. Hierbei kann auch auf aufwendige Frequenzanalysen verzichtet werden. Das Gehäuse 2 weist einen Einlass 39 und einen Auslass 40 auf. 11 shows two pistons 14, 15, which are mounted on shafts 6, 7 and are arranged in the housing 2. A plurality of abrasion elements 31 are arranged on a housing inner wall 32 . With an adjusted number of wear elements 31 on the side of the housing 2, as in 11 shown, the beat frequency can be shifted into a range that is good for detection. Complex frequency analyzes can also be dispensed with here. The housing 2 has an inlet 39 and an outlet 40 .

Die Fig. 12 und 13 zeigen das Abriebselement 33, welches beispielsweise an dem Kolben 14 angeordnet ist. Das Abriebselement 33 weist eine kleine Kontaktfläche 41 auf. Dadurch, dass die mögliche Kontaktfläche 41 mit dem Gehäuse 2 sehr klein ist, führt dies bei einem Kontakt zu einer minimalen Reibleistung und einer geringen Abwärme für die Kontaktdetektion. Besonderer Schwerpunkt ist hier also die Detektion und nicht die verbesserte Schadenstoleranz.the 12 and 13 show the wear element 33, which is arranged, for example, on the piston 14. The abrasion element 33 has a small contact surface 41 . Due to the fact that the possible contact surface 41 with the housing 2 is very small, this leads to minimal friction and low waste heat for contact detection in the event of contact. The main focus here is detection and not improved damage tolerance.

Bezugszahlenreference numbers

11
Vakuumpumpevacuum pump
22
Gehäusecasing
33
Gehäuseteil des SchöpfraumesHousing part of the suction chamber
44
Gehäuseteil des GetrieberaumesHousing part of the gear compartment
55
Schmiermittelspeicherlubricant reservoir
66
Wellewave
77
Wellewave
88th
Wälzlagerroller bearing
99
Kupplungcoupling
1010
Getriebetransmission
1111
Zahnradgear
1212
Zahnradgear
1313
Getriebedeckelgear cover
1414
KolbenPistons
1515
KolbenPistons
1616
Schleuderscheibecentrifugal disc
1717
Kühlrippecooling fin
1818
LüfterFan
1919
Kühlrippecooling fin
2020
Teilbereichsubarea
3131
Antriebselement/AbriebselementDrive element / wear element
3232
Gehäuseinnenwandhousing inner wall
3333
Antriebselement/AbriebselementDrive element / wear element
3434
Drahtwire
3535
Grundkörperbody
3838
Sensorsensor
3939
Einlassinlet
4040
Auslassoutlet
4141
Kontaktfläche eines AbriebselementesContact surface of a wear element

Claims (5)

  1. A vacuum pump with a housing, two shafts arranged in the housing and rotatably driven by a drive and with a gearing coupled to the shaft, in which there is arranged between a piston (14, 15) arranged on the shaft (6, 7) or a screw member arranged on the shaft and an inner side (32) of the housing (2) or a stator
    - at least one sensor (38) and at least one stop element (31, 33) or
    - at least one sensor (38) and an abrasion element (31, 33), characterised in that there is provided at least one acceleration sensor or at least one vibration sensor, which is formed as an acceleration sensor or a vibration sensor which, upon a contact between the piston or the screw member and the stop element (31, 33) or the abrasion element (31, 33), detects a signal which is characteristic of the contact, and in that the at least one stop element (31, 33) or the at least one abrasion element (31, 33) has a lower height than the gap height specified during normal operation between piston (14) or screw member and inner side (32) of the housing (2) or stator.
  2. A method for the detection of a contact between at least one rotor and a stator of a vacuum pump with the features according to claim 1, characterised in that there is provided at least one acceleration sensor or at least one vibration sensor, which upon a contact between the piston (14, 15) or the screw member and the stop element (31, 33) or the at least one abrasion element (31, 33) detects a signal which is characteristic for the contact.
  3. A method according to claim 2 for the detection of a contact between the at least one rotor and a stator of a vacuum pump, characterised in that, upon a contact of the piston (14, 15) or the screw member with the at least one sensor (38), an evaluation unit detects the contact.
  4. A method according to claim 3, characterised in that there is provided an evaluation unit, which evaluates the signals of the at least one sensor.
  5. A method according to claim 4, characterised in that the evaluation unit, upon determination of an incipient contact between rotor and stator, initiates measures for the avoidance of damage.
EP15157105.6A 2015-03-02 2015-03-02 Vacuum pump and method for detecting a contact between at least one rotor and a stator of a vacuum pump Active EP3064775B1 (en)

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EP15157105.6A EP3064775B1 (en) 2015-03-02 2015-03-02 Vacuum pump and method for detecting a contact between at least one rotor and a stator of a vacuum pump

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Application Number Priority Date Filing Date Title
EP15157105.6A EP3064775B1 (en) 2015-03-02 2015-03-02 Vacuum pump and method for detecting a contact between at least one rotor and a stator of a vacuum pump

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EP3064775A1 EP3064775A1 (en) 2016-09-07
EP3064775B1 true EP3064775B1 (en) 2022-01-26

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Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB201621618D0 (en) * 2016-12-19 2017-02-01 Edwards Ltd Pump sealing
GB2588890A (en) * 2019-10-24 2021-05-19 Edwards Ltd Sensor assembly

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5225949A (en) * 1975-08-23 1977-02-26 Shimadzu Corp Brake-loaded oil pressure motor
US4787831A (en) * 1983-09-20 1988-11-29 Air Products And Chemicals, Inc. Dual seal system for roots blower
JPS61104187A (en) * 1984-10-29 1986-05-22 Hitachi Ltd Shaft sealing device for vacuum pump
FR2812041A1 (en) * 2000-07-20 2002-01-25 Cit Alcatel Cooling of a vacuum pump used in the semiconductor industry, uses proximity sensor to control the cooling of the stator in maintain the optimum play between stator and rotor
WO2010046976A1 (en) * 2008-10-22 2010-04-29 株式会社前川製作所 Refueling screw compressor
DE102008060540A1 (en) 2008-12-04 2010-06-10 Pfeiffer Vacuum Gmbh Roots
US8564449B2 (en) * 2010-01-12 2013-10-22 Siemens Energy, Inc. Open circuit wear sensor for use with a conductive wear counterface
US9243631B2 (en) * 2011-04-07 2016-01-26 Imo Industries, Inc. System and method for monitoring pump lining wear

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