EP4459131A2 - Pompe à vide turbomoléculaire à alimentation en gaz de barrage optimisée - Google Patents

Pompe à vide turbomoléculaire à alimentation en gaz de barrage optimisée Download PDF

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Publication number
EP4459131A2
EP4459131A2 EP24200029.7A EP24200029A EP4459131A2 EP 4459131 A2 EP4459131 A2 EP 4459131A2 EP 24200029 A EP24200029 A EP 24200029A EP 4459131 A2 EP4459131 A2 EP 4459131A2
Authority
EP
European Patent Office
Prior art keywords
pump
sealing gas
channel
partition wall
annular
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.)
Pending
Application number
EP24200029.7A
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German (de)
English (en)
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EP4459131A3 (fr
Inventor
Erfindernennung liegt noch nicht vor Die
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.)
Pfeiffer Vacuum Technology AG
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Pfeiffer Vacuum Technology AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pfeiffer Vacuum Technology AG filed Critical Pfeiffer Vacuum Technology AG
Priority to EP24200029.7A priority Critical patent/EP4459131A3/fr
Publication of EP4459131A2 publication Critical patent/EP4459131A2/fr
Publication of EP4459131A3 publication Critical patent/EP4459131A3/fr
Priority to JP2025084685A priority patent/JP2026053254A/ja
Priority to CN202510847262.XA priority patent/CN121654605A/zh
Pending 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
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D19/00—Axial-flow pumps
    • F04D19/02—Multi-stage pumps
    • F04D19/04—Multi-stage pumps specially adapted to the production of a high vacuum, e.g. molecular pumps
    • F04D19/042—Turbomolecular vacuum pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D25/00—Pumping installations or systems
    • F04D25/02—Units comprising pumps and their driving means
    • F04D25/06—Units comprising pumps and their driving means the pump being electrically driven
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/05—Shafts or bearings, or assemblies thereof, specially adapted for elastic fluid pumps
    • F04D29/056—Bearings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/08—Sealings
    • F04D29/083—Sealings especially adapted for elastic fluid pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/40—Casings; Connections of working fluid
    • F04D29/52—Casings; Connections of working fluid for axial pumps
    • F04D29/522—Casings; Connections of working fluid for axial pumps especially adapted for elastic fluid pumps

Definitions

  • the present invention relates to a turbomolecular vacuum pump with optimized sealing gas supply.
  • the invention relates to a turbomolecular vacuum pump with a Holweck pump stage, within which the electric motor of the turbomolecular vacuum pump, also referred to here simply as a turbomolecular pump or "pump", is located, with a sealing gas inlet opening into the Holweck pump stage, via which a sealing gas can be introduced to protect the motor and the adjoining bearing area from corrosive components that may be part of the process gas to be pumped.
  • Such components do not necessarily have to have a corrosive effect; rather, these components can also be particles or dust that can contaminate the operating medium or clog gaps. Furthermore, other components can also simply contaminate the operating medium.
  • sealing gas Since the sealing gas is usually introduced into the pump system near a rolling bearing, which is usually oil-lubricated, it can happen, especially when large quantities of sealing gas are introduced into the pump system, that the sealing gas absorbs and carries with it oil vapors that can diffuse out of the bearing area.
  • the sealing gas enriched with oil can then spread in the pump system and in this way reach an instrument connected to the pump inlet, where it can cause incorrect measurements and/or damage.
  • the sealing gas spreading in the pump system can reach the forevacuum area near the pump outlet, which is connected to the outlet of the Holweck pump stage. Fluid connection, where the oil particles in the barrier gas can settle as an oil film, which can cause irritation to the user of the pump.
  • the invention is therefore based on the object of specifying a turbomolecular vacuum pump with a Holweck pump stage and a sealing gas inlet, in which the probability that the sealing gas absorbs oil particles from the bearing area is minimized.
  • the object is achieved in that in the cylindrical partition wall, which is part of an engine cover and which separates the engine compartment from the pre-vacuum area at the outlet of the Holweck pump stage located furthest downstream, at least one inflow channel is formed which is aligned essentially axially with respect to the rotor axis and which is in fluid communication at one end with the sealing gas connection and at the other end via a flow path, which can be of complex design, with the annular space at the pre-vacuum level which surrounds the cylindrical partition wall of the engine cover in question.
  • the at least one inflow channel is aligned essentially axially and thus extends inside the cylindrical partition wall.
  • the end of the inflow channel which is in fluid communication with the sealing gas connection is located in the axial direction on a different radially extending plane than the other end of the inflow channel.
  • the radial planes in which the two ends of the inflow channel are located are therefore spaced apart from one another in the axial direction.
  • the sealing gas is therefore not introduced in a radial direction directly into the engine compartment, where, due to the fact that the engine compartment is directly adjacent to the bearing area of the pump rotor, the probability of oil being absorbed by the sealing gas from the bearing area is high; rather, due to the fact that the inflow channel in question is formed in or within the axially extending cylindrical partition, the sealing gas is initially guided through the inflow channel in an axial direction away from the bearing area and in the direction of the electric motor or in the direction of the first pump mechanism, thereby minimizing the probability of oil being absorbed from the bearing area.
  • the sealing gas If the sealing gas is guided into the engine compartment after flowing through the inflow channel close to the radially extending partition of the engine cover, it can then spread through the engine/rotor gap in the direction of the bearing area, where it then represents a type of buffer or barrier for the sealing gas subsequently flowing through the inflow channel. Instead, the inflowing sealing gas then passes through the annular gap between the rotor and the radially extending partition wall of the engine cover into the annular space surrounding the cylindrical partition wall, which is at pre-vacuum level, whereby this inflowing sealing gas contains no or only small amounts of oil vapor due to the fact that it does not come into contact with the bearing area due to the buffer effect of the sealing gas initially flowing into the engine compartment.
  • the sealing gas spreading in the pump system cannot come into contact with the bearing area; rather, the sealing gas is initially guided away from the bearing area in an axial direction through the essentially axially extending inflow channel, which minimizes the probability of oil vapors being absorbed by the sealing gas. As a result, larger quantities of sealing gas can be admitted.
  • purge gas connection can also be used for flooding during pump shutdown, larger quantities of purge gas can be used, which shortens the time required to shut down the pump.
  • the sealing gas connection is formed in a housing lower part of the housing of the turbomolecular vacuum pump, wherein this housing lower part accommodates the roller bearing or the bearing holder that contains the roller bearing.
  • the cylindrical partition wall which together with the radially extending partition wall forms the motor cover, extends from a radial plane in which the roller bearing is located, in the axial direction to an upper housing part connected to the housing lower part, in which the first pump mechanism is located and which together with the housing lower part forms a receiving space for the second pump mechanism including the electric motor.
  • the at least one sealing gas connection which can be provided on the housing bottom part, is in fluid communication with the inflow channel via a sealing gas channel extending in the radial direction, which is also formed in the housing bottom part.
  • a sealing gas channel extending in the radial direction, which is also formed in the housing bottom part.
  • the turbomolecular vacuum pump and in particular the housing lower part has at least two sealing gas connections, one of which is provided at a radially outer end of the sealing gas channel, whereas the other sealing gas connection is in fluid communication with the sealing gas channel via a sealing gas bore that opens into the sealing gas channel at a point that is located radially inside the radially outer end of the sealing gas channel.
  • the other sealing gas connection can be provided on an underside of the housing lower part and connected to the sealing gas channel by an axially extending sealing gas bore. In confined spaces, sealing gas can thus be supplied to the pump in the radial or axial direction as required by means of a corresponding sealing gas supply line.
  • a further embodiment can provide for the inflow channel to open downstream into a circumferential ring channel which is formed circumferentially in the cylindrical partition wall and which in turn is in fluid communication with the annular space, possibly via the engine compartment, via a flow path which can be complex.
  • the sealing gas can thus spread and distribute itself in the circumferential direction through the ring channel in order to reach the engine compartment and/or the annular space surrounding the cylindrical partition wall.
  • the cylindrical partition wall is composed of two axially aligned cylindrical wall sections, wherein the annular channel at the connection point is formed at which the two cylindrical wall sections are connected to one another.
  • this can be done so that a first of the two cylindrical wall sections extends from the lower housing part in the direction of the first pump mechanism to a free end at which the first cylindrical wall section is connected to the second of the two cylindrical wall sections, which from there also extends in the direction of the first pump mechanism to an end at which the radially extending partition is connected to the second cylindrical wall section.
  • an annular circumferential recess can be formed at the free end of the first cylindrical wall section and/or at the adjoining end of the second cylindrical wall section, which then forms the annular channel when the two cylindrical wall sections are connected to one another.
  • the first cylindrical wall section has a circumferential first annular projection at its free end, which has a smaller thickness than the first cylindrical wall section.
  • the end of the second cylindrical wall section which is connected to the free end of the first cylindrical wall section, can have a circumferential second annular projection that surrounds the first annular projection and has a smaller thickness than the second cylindrical wall section.
  • the annular channel between the two annular projections can be created by a chamfer or rounding that is formed circumferentially along the inner edge of the free end of the second annular projection.
  • the sealing gas In order for the sealing gas to be able to pass from the annular channel into the engine compartment, it can be provided according to a further embodiment that the engine compartment is in fluid communication with the annular channel via at least one distribution channel defined by the cylindrical partition wall.
  • the connecting channels are provided, which are spaced apart from one another in the circumferential direction of the annular channel, preferably evenly, in order to ensure that the engine compartment is supplied with sealing gas as evenly as possible.
  • the distribution channels at least partially have flow cross-sections that are different from one another and/or that the flow cross-section of the ring channel increases with increasing distance from the inflow channel in the circumferential direction.
  • those distribution channels that are further away from the inflow channel in the circumferential direction than distribution channels located closer to the inflow channel have a larger flow cross-section than the distribution channels located closer to the inflow channel.
  • the sealing gas seeks the path of least resistance, it can thus be ensured that the sealing gas entering the ring channel via the inflow channel does not immediately escape again through the distribution channels located in the immediate vicinity of the inflow channel, but can also reach the distribution channels further away from the inflow channel, thus ultimately ensuring an even distribution of the sealing gas through all distribution channels.
  • a section of the respective distribution channel is formed by an axially extending recess in the first and/or in the second cylindrical wall section, preferably by a respective axially extending recess in the first and/or in the second annular projection.
  • the second cylindrical wall section can be penetrated by a slot extending in the axial direction, so that the sealing gas can pass through it. can escape from the annular channel to flow towards the radially extending partition of the engine cover.
  • the electric motor in the engine compartment has a motor stator which only rests on the inside of the cylindrical partition wall along a central circumferential region.
  • the motor stator On the side of the central circumferential region facing the first pump mechanism, however, the motor stator is spaced from the cylindrical partition wall by a circumferential annular space. Since the motor stator does not rest on the inside of the cylindrical partition wall in the region of the annular space in question, the at least one distribution channel described above can open into the engine compartment in this region.
  • Sealing gas which reaches the annular space between the motor stator and the cylindrical partition wall through the distribution channels mentioned above can thus spread further from there in the engine compartment in the axial direction in order to reach a distance which serves as an expansion volume and by which the motor stator is spaced from the radially extending partition wall on its side facing the first pump mechanism. Since the annular gap between the radially extending partition wall and the rotor of the pump is directly connected to the expansion volume in question, the annular gap can thus be sealed by the sealing gas, which prevents corrosive components from the process gas from entering the interior of the engine compartment.
  • the sealing gas thus passes from the ring channel via the motor compartment to the ring gap, from where it can pass through the ring space surrounding the cylindrical partition wall, which is at pre-vacuum level, to the outlet of the Holweck pump stage.
  • the ring channel is directly connected to the ring space via at least one distribution channel which extends in the radial direction through the cylindrical partition wall. is in fluid communication radially outside the cylindrical partition wall, wherein preferably several such distribution channels can be provided, which are spaced apart from one another in the circumferential direction of the ring channel, preferably evenly.
  • the distribution channels at least partially have flow cross-sections that are different from one another and/or that the flow cross-section of the ring channel increases with increasing distance from the inflow channel in order to achieve the most even distribution of the sealing gas possible.
  • the cylindrical partition wall is surrounded on the outer circumference by a blocking geometry such as a circumferential ring flange.
  • the blocking geometry is preferably located closer in the axial direction to the radially extending partition wall of the engine cover than the distribution channels penetrating the cylindrical partition wall. This can ensure that process gas escaping from the Holweck pump stage cannot even reach the blocking geometry, whereby the annular space surrounding the cylindrical partition wall is also effectively protected from corrosive components of the process gas.
  • the blocking geometry can also be designed as a pump-active structure in the manner of a Holweck threaded section, which reduces the probability of process gas flowing into the annular space surrounding the cylindrical partition wall.
  • the turbomolecular pump 111 shown comprises a pump inlet 115 surrounded by an inlet flange 113, to which a recipient (not shown) can be connected in a manner known per se.
  • the gas from the recipient can be sucked out of the recipient via the pump inlet 115 and conveyed through the pump to a pump outlet 117, to which a backing pump, such as a rotary vane pump, can be connected.
  • the inlet flange 113 forms the vacuum pump in accordance with Fig. 1 the upper end of the housing 119 of the vacuum pump 111.
  • the housing 119 comprises a lower part 121, on which an electronics housing 123 is arranged on the side. Electrical and/or electronic components of the vacuum pump 111 are housed in the electronics housing 123, e.g. for operating an electric motor 125 arranged in the vacuum pump (see also Fig. 3 ).
  • Several connections 127 for accessories are provided on the electronics housing 123.
  • a data interface 129 e.g. according to the RS485 standard, and a power supply connection 131 are arranged on the electronics housing 123.
  • turbomolecular pumps that do not have such an attached electronics housing, but are connected to external drive electronics.
  • a flood inlet 133 in particular in the form of a flood valve, is provided on the housing 119 of the turbomolecular pump 111, via which the vacuum pump 111 can be flooded.
  • a sealing gas connection 135, which is also referred to as a purge gas connection is also arranged, via which purge gas can be fed to protect the electric motor 125 (see e.g. Fig. 3 ) before the gas delivered by the pump can be let into the motor compartment 137, in which the electric motor 125 is housed in the vacuum pump 111.
  • two coolant connections 139 are also arranged, wherein one of the coolant connections is provided as an inlet and the other coolant connection as an outlet for coolant that can be fed into the vacuum pump for cooling purposes.
  • Other existing turbomolecular vacuum pumps (not shown) are operated exclusively with air cooling.
  • the lower side 141 of the vacuum pump can serve as a base so that the vacuum pump 111 can be operated standing on the underside 141.
  • the vacuum pump 111 can also be attached to a recipient via the inlet flange 113 and thus operated in a hanging position.
  • the vacuum pump 111 can be designed in such a way that it can also be put into operation when it is aligned in a different way than in Fig. 1 is shown. It is also possible to realize embodiments of the vacuum pump in which the underside 141 is not arranged facing downwards, but rather facing to the side or facing upwards. In principle, any angle is possible.
  • Mounting holes 147 are also arranged on the underside 141, via which the pump 111 can be attached to a support surface, for example. This is not possible with other existing turbomolecular vacuum pumps (not shown), which are in particular larger than the pump shown here.
  • a coolant line 148 is shown in which the coolant introduced and discharged via the coolant connections 139 can circulate.
  • the vacuum pump comprises several process gas pumping stages for conveying the process gas present at the pump inlet 115 to the pump outlet 117.
  • a rotor 149 is arranged in the housing 119 and has a rotor shaft 153 rotatable about a rotation axis 151.
  • the turbomolecular pump 111 comprises several turbomolecular pump stages connected in series with a pumping effect, with several radial rotor disks 155 attached to the rotor shaft 153 and stator disks 157 arranged between the rotor disks 155 and fixed in the housing 119.
  • a rotor disk 155 and an adjacent stator disk 157 each form a turbomolecular pump stage.
  • the stator disks 157 are held at a desired axial distance from one another by spacer rings 159.
  • the vacuum pump also comprises Holweck pump stages arranged one inside the other in the radial direction and connected in series to pump effectively. There are other turbomolecular vacuum pumps (not shown) that do not have Holweck pump stages.
  • the rotor of the Holweck pump stages comprises a rotor hub 161 arranged on the rotor shaft 153 and two cylinder-jacket-shaped Holweck rotor sleeves 163, 165 which are fastened to the rotor hub 161 and supported by it, which are oriented coaxially to the rotation axis 151 and are nested in the radial direction. Furthermore, two cylinder-jacket-shaped Holweck stator sleeves 167, 169 which are also oriented coaxially to the rotation axis 151 and are nested in each other in the radial direction.
  • the pump-active surfaces of the Holweck pump stages are formed by the lateral surfaces, i.e. by the radial inner and/or outer surfaces, of the Holweck rotor sleeves 163, 165 and the Holweck stator sleeves 167, 169.
  • the radial inner surface of the outer Holweck stator sleeve 167 is opposite the radial outer surface of the outer Holweck rotor sleeve 163, forming a radial Holweck gap 171, and together with this forms the first Holweck pump stage following the turbomolecular pumps.
  • the radial inner surface of the outer Holweck rotor sleeve 163 is opposite the radial outer surface of the inner Holweck stator sleeve 169, forming a radial Holweck gap 173, and together with this forms a second Holweck pump stage.
  • the radial inner surface of the inner Holweck stator sleeve 169 lies opposite the radial outer surface of the inner Holweck rotor sleeve 165, forming a radial Holweck gap 175 and together forms the third Holweck pump stage.
  • a radially extending channel can be provided at the lower end of the Holweck rotor sleeve 163, via which the radially outer Holweck gap 171 is connected to the middle Holweck gap 173.
  • a radially extending channel can be provided at the upper end of the inner Holweck stator sleeve 169, via which the middle Holweck gap 173 is connected to the radially inner Holweck gap 175.
  • a connecting channel 179 to the outlet 117 can also be provided at the lower end of the radially inner Holweck rotor sleeve 165.
  • the above-mentioned pump-active surfaces of the Holweck stator sleeves 167, 169 each have a plurality of Holweck grooves running spirally around the rotation axis 151 in the axial direction, while the opposite lateral surfaces of the Holweck rotor sleeves 163, 165 are smooth and drive the gas in the Holweck grooves to operate the vacuum pump 111.
  • a rolling bearing 181 is provided in the area of the pump outlet 117 and a permanent magnet bearing 183 is provided in the area of the pump inlet 115.
  • a conical spray nut 185 with an outer diameter that increases towards the roller bearing 181 is provided on the rotor shaft 153.
  • the spray nut 185 is in sliding contact with at least one scraper of a fluid reservoir.
  • a spray screw can be provided instead of a spray nut. Since different designs are thus possible, the term "spray tip" is also used in this context.
  • the operating fluid storage comprises several absorbent disks 187 stacked on top of each other, which are impregnated with an operating fluid for the rolling bearing 181, e.g. with a lubricant.
  • the operating fluid is transferred by capillary action from the operating fluid reservoir via the scraper to the rotating spray nut 185 and, as a result of the centrifugal force, is conveyed along the spray nut 185 in the direction of the increasing outer diameter of the spray nut 185 to the roller bearing 181, where it fulfills a lubricating function, for example.
  • the roller bearing 181 and the operating fluid reservoir are enclosed in the vacuum pump by a trough-shaped insert 189 and the bearing cover 145.
  • the permanent magnet bearing 183 comprises a rotor-side bearing half 191 and a stator-side bearing half 193, each of which comprises a ring stack of several permanent magnetic rings 195, 197 stacked on top of one another in the axial direction.
  • the ring magnets 195, 197 lie opposite one another to form a radial bearing gap 199, with the rotor-side ring magnets 195 being arranged radially on the outside and the stator-side ring magnets 197 being arranged radially on the inside.
  • the magnetic field present in the bearing gap 199 causes magnetic repulsion forces between the ring magnets 195, 197, which cause the rotor shaft 153 to be supported radially.
  • the rotor-side ring magnets 195 are carried by a support section 201 of the rotor shaft 153, which surrounds the ring magnets 195 on the radial outside.
  • the stator-side ring magnets 197 are supported by a stator-side support section 203 which extends through the ring magnets 197 and is suspended from radial struts 205 of the housing 119.
  • the rotor-side ring magnets 195 are fixed parallel to the rotation axis 151 by a cover element 207 coupled to the support section 201.
  • the stator-side ring magnets 197 are fixed parallel to the rotation axis 151 in one direction by a fastening ring 209 connected to the support section 203 and a fastening ring 211 connected to the support section 203.
  • a disc spring 213 can also be provided between the fastening ring 211 and the ring magnets 197.
  • An emergency or safety bearing 215 is provided within the magnetic bearing, which runs idle without contact during normal operation of the vacuum pump 111 and only engages when there is excessive radial deflection of the rotor 149 relative to the stator, in order to form a radial stop for the rotor 149, so that a collision of the rotor-side structures with the stator-side structures is prevented.
  • the safety bearing 215 is designed as an unlubricated roller bearing and forms a radial gap with the rotor 149 and/or the stator, which causes the safety bearing 215 to be disengaged during normal pumping operation.
  • the radial deflection at which the safety bearing 215 engages is large enough so that the safety bearing 215 does not engage during normal operation of the vacuum pump, and at the same time small enough so that a collision of the rotor-side structures with the stator-side structures is prevented under all circumstances.
  • the vacuum pump 111 comprises the electric motor 125 for rotating the rotor 149.
  • the armature of the electric motor 125 is formed by the rotor 149, whose rotor shaft 153 extends through the motor stator 217.
  • a permanent magnet arrangement can be arranged radially on the outside or embedded on the section of the rotor shaft 153 extending through the motor stator 217.
  • the motor stator 217 is fixed in the housing within the motor compartment 137 provided for the electric motor 125.
  • a sealing gas which is also referred to as purge gas and which can be air or nitrogen, for example, can enter the motor compartment 137 via the sealing gas connection 135.
  • the electric motor 125 can be protected from process gas, e.g. from corrosive components of the process gas, via the sealing gas.
  • the motor compartment 137 can also be evacuated via the pump outlet 117, i.e. the vacuum pressure in the motor compartment 137 is at least approximately the vacuum pressure caused by the forevacuum pump connected to the pump outlet 117.
  • a so-called labyrinth seal 223, which is known per se, can be provided between the rotor hub 161 and a wall 221 delimiting the motor compartment 137, in particular in order to achieve a better sealing of the motor compartment 217 with respect to the Holweck pump stages located radially outside.
  • the sealing gas passes through the sealing gas connection 135 in the manner already described directly into the motor compartment 137, which is largely separated in terms of flow from the pre-vacuum area at the outlet of the Holweck pump stage by the wall 221, also referred to below as the motor cover, and in particular by the labyrinth seal 223.
  • the sealing gas flowing into the motor compartment 137 can undesirably absorb oil vapors that diffuse from the roller bearing 181 into the motor compartment 137.
  • the sealing gas enriched with oil in this way can then flow through the gap 219 and through the labyrinth seal 223, from where it can reach the connecting channel 179 at the outlet of the Holweck pump stage, where it can precipitate in an undesirable manner as an oil film.
  • the sealing gas channel 302 which extends radially inwards from the sealing gas connection 304 in the housing lower part 306, does not open directly into the motor compartment 320, but that the sealing gas channel 302 continues in an adjoining inflow channel 312, which is formed in the motor cover and in particular in its cylindrical partition wall 314.
  • the sealing gas flowing in through the sealing gas channel 302 is thus initially guided away from the bearing area in which the roller bearing 318 is located in the axial direction, in order to then reach the annular space 320 surrounding the cylindrical partition wall 314 via a flow path described in more detail later.
  • the pump in the figure is indeed a split-flow pump; however, the sealing gas concept according to the invention can of course also be used in a conventional turbomolecular pump according to Figs. 1 to 5 be realized.
  • the turbomolecular vacuum pump 300 provides that the sealing gas channel 302, which extends radially inwards from the sealing gas connection 304 in the housing lower part 306, continues in an axially extending inflow channel 312, which is formed within the cylindrical partition wall 314 of the motor cover.
  • the pump 300 has an axially aligned sealing gas connection 305, which is in fluid communication with the sealing gas channel 302 via a sealing gas bore 307, so that sealing gas can be supplied to the inflow channel 312 via the radial sealing gas connection 304 and/or the axial sealing gas connection 305 as required.
  • the cylindrical partition 314, which surrounds the motor compartment 310 on the circumference, is composed of a first cylindrical wall section 322 and a second cylindrical wall section 324.
  • the first cylindrical wall section 322 extends from the housing base 308 in the direction of the first pump mechanism, which is formed by the rotor and stator disks of the turbomolecular pump mechanism.
  • the free end of this first cylindrical wall section 322 is connected in the manner described in more detail below to the second cylindrical wall section 324, which extends from the free end of the first cylindrical wall section 322 in the direction of the first pump mechanism to an end at which the radially extending partition 316 is connected to the second cylindrical wall section 324.
  • the first cylindrical wall section 322 has at its free end a circumferential first annular projection 326 extending therefrom, the thickness of this first annular projection 326 being less than that of the first cylindrical wall section 322.
  • the end of the second cylindrical wall section 324 connected to the free end of the first cylindrical wall section 322 also has a circumferential second annular projection 328, the thickness of which is less than that of the second cylindrical wall section 324.
  • the second annular projection 328 surrounds the first annular projection 326 and can be screwed or pressed onto it, for example.
  • the first annular projection 326 has a recess in the form of a slot 334 extending in the axial direction, wherein this recess can continue as a groove on the inside of the second cylindrical wall section 324. Sealing gas that reaches the annular channel 332 via the inflow channel 312 can thus spread in the axial direction through the distribution channel 336 designed as a slot 334 and the groove (not shown) continuing therefrom on the inside of the second cylindrical wall section 324, in order to reach from there into the upper region of the engine compartment 310.
  • a further distribution channel 336 branches off from the ring channel 332 in the axial direction, which on the side of the ring channel 332 opposite the distribution channel 336 formed by the slot 334.
  • this distribution channel 336 is formed by an axially extending slot 338 in the lower ring projection 326 and by a recess 340 in the second ring projection 328, which, like the slot 338, extends in the axial direction.
  • the distribution channel 336 formed by this slot 338 and by the recess 340 has a larger flow cross-section than the distribution channel 336 formed by the slot 334, which can ensure that approximately the same amount of sealing gas can reach the engine compartment 310 through both distribution channels 336.
  • distribution channels 336 branch off from the ring channel 332 in the axial direction
  • three or more distribution channels 336 can also branch off from the ring channel 332, as shown in the Fig. 8 are indicated by dashed lines as semicircular recesses in the two annular projections 326, 328, whereby these additional distribution channels 336 should preferably be evenly spaced from one another in the circumferential direction.
  • the flow cross-section of the respective distribution channels 336 should preferably be larger the further they are from the inflow channel 312 in the circumferential direction, in order to ensure a uniform supply of sealing gas to the engine compartment 310.
  • the flow cross-section of the ring channel 332 can increase with increasing distance from the inflow channel 312, since this can also ensure that the distribution channels 336 further away from the inflow channel 312 essentially have the same Amount of sealing gas can flow in the engine compartment 310 as through the distribution channels 336 located closer to the inflow channel 312.
  • the fact that the sealing gas can flow unhindered into the motor compartment 310 through the previously described distribution channels 336 is due to the fact that the motor stator 342 only rests against the cylindrical partition wall 314 along the inside of a central circumferential region 344.
  • the motor stator 342 is spaced from the cylindrical partition wall 314 on both sides of this central region 344 by an annular space 346, so that on the side of the central circumferential region 344 facing the first pump mechanism, the sealing gas can flow unhindered from the distribution channels 336 into the annular space 346, from where it can expand further in the direction of the annular gap 348, through which the rotor 356 is separated from the radially extending partition wall 316.
  • the sealing gas expands in the area serving as expansion volume 350, which is formed by the distance between the motor stator 342 and the radially extending partition wall 316.
  • Sealing gas that reaches the annular gap 348 on the previously described flow path thus reliably seals it, and due to the fact that the sealing gas does not come into contact with oil vapors from the rolling bearing 380 on its way to the annular gap 348, it can be prevented that the sealing gas entrains oil particles from the rolling bearing 318 on its further path to the annular space 320 surrounding the cylindrical partition wall 314, which could otherwise undesirably precipitate as an oil film in the forevacuum area at the outlet of the Holweck pump stage.
  • the sealing gas volume represents a buffer for sealing gas flowing into the expansion volume 350, so that when sealing gas is continuously applied during pumping operation, no further sealing gas can flow into the lower region of the motor compartment 310.
  • the lower region of the motor compartment 310 is therefore not flowed through by sealing gas during pumping operation, which can prevent the sealing gas from entraining oil particles from the roller bearing 318 on its way to the annular gap 348, which could otherwise subsequently settle as an oil film in the pre-vacuum region.
  • the sealing gas channel 302 initially merges into an annular channel 332 in the housing lower part 306, from where several inflow channels 312 extend upwards in the cylindrical partition wall 314, wherein these inflow channels 312 are in fluid communication with the annular space 320 outside the cylindrical partition wall 314 via radial bores.
  • the cylindrical partition wall 314 is is surrounded by a blocking geometry 354, such as an annular flange here, which prevents process gas from flowing back via the annular space 320 into the motor space 310.
  • the blocking geometry can also be designed as a pump-active structure in the manner of a Holweck thread section, which reduces the probability of process gas flowing into the annular space surrounding the cylindrical partition wall.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Non-Positive Displacement Air Blowers (AREA)
EP24200029.7A 2024-09-12 2024-09-12 Pompe à vide turbomoléculaire à alimentation en gaz de barrage optimisée Pending EP4459131A3 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP24200029.7A EP4459131A3 (fr) 2024-09-12 2024-09-12 Pompe à vide turbomoléculaire à alimentation en gaz de barrage optimisée
JP2025084685A JP2026053254A (ja) 2024-09-12 2025-05-21 シールガス供給が最適化されたターボ分子真空ポンプ
CN202510847262.XA CN121654605A (zh) 2024-09-12 2025-06-24 具有优化的屏蔽气导入结构的涡轮分子真空泵

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP24200029.7A EP4459131A3 (fr) 2024-09-12 2024-09-12 Pompe à vide turbomoléculaire à alimentation en gaz de barrage optimisée

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EP4459131A2 true EP4459131A2 (fr) 2024-11-06
EP4459131A3 EP4459131A3 (fr) 2025-04-09

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EP (1) EP4459131A3 (fr)
JP (1) JP2026053254A (fr)
CN (1) CN121654605A (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4707609A3 (fr) * 2025-12-30 2026-07-29 Pfeiffer Vacuum Technology AG Rotor pour pompe turbomoleculaire et pompe turbomoleculaire

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3456558B2 (ja) * 1995-07-24 2003-10-14 株式会社島津製作所 ターボ分子ポンプ
JPH10299689A (ja) * 1997-04-21 1998-11-10 Daikin Ind Ltd 排気ポンプ
DE202006017846U1 (de) * 2006-11-23 2008-03-27 Oerlikon Leybold Vacuum Gmbh Hochvakuumpumpe
JP2014134168A (ja) * 2013-01-11 2014-07-24 Shimadzu Corp 真空ポンプ
CN115199571B (zh) * 2021-04-02 2025-07-25 株式会社岛津制作所 真空泵
EP4108931B1 (fr) * 2022-09-01 2024-06-26 Pfeiffer Vacuum Technology AG Procédé permettant de faire fonctionner une pompe à vide moléculaire pour obtenir une puissance d'aspiration améliorée

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4707609A3 (fr) * 2025-12-30 2026-07-29 Pfeiffer Vacuum Technology AG Rotor pour pompe turbomoleculaire et pompe turbomoleculaire

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EP4459131A3 (fr) 2025-04-09
JP2026053254A (ja) 2026-03-25

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