EP4108931B1 - Procédé permettant de faire fonctionner une pompe à vide moléculaire pour obtenir une puissance d'aspiration améliorée - Google Patents

Procédé permettant de faire fonctionner une pompe à vide moléculaire pour obtenir une puissance d'aspiration améliorée Download PDF

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Publication number
EP4108931B1
EP4108931B1 EP22193499.5A EP22193499A EP4108931B1 EP 4108931 B1 EP4108931 B1 EP 4108931B1 EP 22193499 A EP22193499 A EP 22193499A EP 4108931 B1 EP4108931 B1 EP 4108931B1
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EP
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Prior art keywords
pump
carrier gas
turbomolecular
inlet
stage
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German (de)
English (en)
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EP4108931A1 (fr
Inventor
Jonas HÖLZ
Jan Hofmann
Maximilian Birkenfeld
Peter Vorwerk
Gilbrich Sönke
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Pfeiffer Vacuum Technology AG
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Pfeiffer Vacuum Technology AG
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Priority to JP2023072957A priority patent/JP2024035054A/ja
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    • 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
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/02—Surge control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/02—Surge control
    • F04D27/0207—Surge control by bleeding, bypassing or recycling fluids
    • F04D27/0238—Details or means for fluid reinjection

Definitions

  • the present invention relates to a method according to the preamble of claim 1 for operating a molecular vacuum pump to achieve an improved suction capacity, such as the type essentially consisting of EP 0 974 756 A2 known. Furthermore, EP 3 438 460 A1 , JP H03 233193 A , US 5 092 740 A and EN 25 07 430 A1 pointed out.
  • Molecular vacuum pumps operate in the high and ultra-high vacuum range, with the pressure in the high vacuum range being between 10 -3 and 10 -7 hPa and in the ultra-high vacuum range being less than and 10 -7 hPa.
  • the process gas to be pumped from the pump inlet to the pump outlet tends to flow back from the pump outlet to the pump inlet due to the fact that the pressure at the pump inlet is lower than the pressure at the pump outlet.
  • This tendency for backflow is greater the higher the pump pre-pressure, i.e. the pressure at the pump outlet of the vacuum pump. Accordingly, due to the tendency for backflow described, the pumping speed of a turbomolecular pump is lower in the range of high pre-pressures than the pumping speed of the turbomolecular pump at lower pre-pressures.
  • the described backflow problem occurs particularly when pumping process gases that have a relatively low molar mass. This is due to the fact that heavier process gases are easier to pumped than lighter process gases. With relatively light process gases such as hydrogen or helium, a smaller pressure difference between the pump inlet and the pump outlet or a smaller pressure ratio is therefore achieved at the same pre-pressure and other boundary conditions than with heavier process gases, which means that the backflow problem is greater with process gases with a lower molar mass than with process gases with a higher molar mass.
  • the invention is therefore based on the object of reducing the described backflow problem in molecular vacuum pumps such as turbomolecular vacuum pumps and thus ensuring an improved suction capacity.
  • the object underlying the same is achieved with a method for operating a molecular vacuum pump, in particular a turbomolecular vacuum pump, according to claim 1.
  • the tendency of the process gas to flow back can be reduced the more the more carrier gas is introduced; however, the power consumption of the pump increases as the amount of carrier gas increases. Too small carrier gas quantities, on the other hand, do not have the desired effect in terms of reducing the tendency of the process gas to flow back. Tests were therefore carried out to determine the optimum ratio between the amount of process gas and the amount of carrier gas.
  • this can be an operating state during which the molecular vacuum pump is continuously operated with at least 75% of its maximum permissible power or at least 75% of its maximum permissible speed.
  • the carrier gas is continuously introduced into the pump mechanism during at least 50% of this time window, i.e. during the time window during which the molecular vacuum pump is continuously operated with at least 75% of its maximum permissible power or at least 75% of its maximum permissible speed.
  • the carrier gas can be continuously introduced into the pumping mechanism during at least 60% of the time of this time window, in particular during at least 70% of the time of this time window and particularly preferably during at least 80% of the time of this time window.
  • the entraining gas is not only introduced into the pump mechanism temporarily for a relatively short period of time; rather, according to the invention, the entraining gas is introduced into the pump mechanism for the majority of the time during which process gas is conveyed by means of the pump, in order to reduce the tendency of the process gas to flow back in favor of improving the pumping capacity of the pump.
  • the carrier gas is continuously introduced into the pump mechanism over a period of at least one hour during the conveyance of process gas, in particular over a period of at least 10 hours and preferably over a period of more than 24 hours.
  • the carrier gas in order to optimize the momentum transfer from the carrier gas molecules to the process gas molecules, it may prove advantageous, as stated above, to use a gas as the carrier gas that has a larger molar mass than the process gas. Accordingly, it may prove particularly advantageous to use nitrogen and/or argon, for example, as the carrier gas, particularly when the process gas is a relatively light gas, such as hydrogen or helium.
  • the pump stage closest to the pump inlet is referred to as the first pump stage and the pump stage closest to the pump outlet is referred to as the Nth pump stage, whereby the individual pump stages are numbered consecutively with whole numbers from the first to the Nth in the direction of the pump outlet.
  • M 6
  • M 5
  • turbomolecular pump stage closest to the pump inlet is the first and the turbomolecular pump stage closest to the pump outlet is the Nth pump stage, with the individual turbomolecular pump stages being numbered consecutively with whole numbers from the first to the Nth in the direction of the pump outlet.
  • carrier gas a gas other than the process gas into the pump mechanism of the turbomolecular pump through the carrier gas connection during operation, which is also referred to below as carrier gas
  • carrier gas a gas other than the process gas
  • the tendency of the process gas to flow back from the pump outlet to the pump inlet is reduced, since the molecules of the process gas are entrained or dragged along by the molecules of the carrier gas in the direction of the pump outlet, hence the term "carrier gas".
  • the molecules of the carrier gas transfer their momentum to the molecules of the process gas, so that the process gas molecules are dragged along by the carrier gas molecules in the direction of the pump outlet.
  • the greater the molecular weight of the carrier gas the greater the momentum transfer from the carrier gas to the process gas.
  • a gas with a higher molar mass than the process gas should be used as the carrier gas, which is why, for example, in the case of helium or hydrogen as the process gas, nitrogen and/or argon can be used as the carrier gas.
  • the pressure at the pump inlet is reduced at the same pre-pressure, which results in an increase of the pumping speed.
  • the effective high-vacuum side pumping speed of the turbomolecular pump is thus increased by introducing a carrier gas into the pump mechanism, since introducing a carrier gas into the pump mechanism reduces the tendency of the process gas to flow back.
  • This effect is more noticeable the closer the carrier gas connection is to the pump inlet, since in this case more time is available during which the carrier gas molecules can transfer their momentum to the process gas molecules.
  • the carrier gas connection should not be located too close to the pump inlet, since in this case there is a risk that the carrier gas will flow back towards the pump inlet due to the vacuum at the pump inlet. Accordingly, regardless of the number of pump stages, the carrier gas connection should always be located downstream of the first, preferably downstream of the second, pump stage in order to prevent the carrier gas from flowing back towards the pump inlet.
  • the entraining gas connection should be located downstream of the first pumping stage, preferably downstream of the second pumping stage, in order to prevent the entraining gas from flowing back towards the pump inlet.
  • the entraining gas connection should be located downstream of the first pumping stage, preferably downstream of the second pumping stage, in order to prevent the entraining gas from flowing back towards the pump inlet.
  • 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 the alignment according to 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 ) can be let into the motor compartment 137, in which the electric motor 125 is housed in the vacuum pump 111, before the gas delivered by the pump.
  • two coolant connections 139 are also arranged, one of the coolant connections being 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 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 includes Holweck pump stages arranged radially one inside the other and connected in series to pump effectively. There are other turbomolecular vacuum pumps (not shown) that do not have Holweck pumping 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 and supported by the rotor hub 161 and which are oriented coaxially to the rotation axis 151 and nested in one another in the radial direction. Furthermore, two cylinder-jacket-shaped Holweck stator sleeves 167, 169 are provided, which are also oriented coaxially to the rotation axis 151 and are nested in one another 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 forming the third Holweck pumping 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 central Holweck gap 173.
  • a radially extending channel can be provided at the upper end of the inner Holweck stator sleeve 169, via which the central Holweck gap 173 is connected to the radially inner Holweck gap 175.
  • the nested Holweck pump stages are connected in series with one another.
  • a connecting channel 179 to the outlet 117 can also be provided.
  • 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 propel the gas in the Holweck grooves for operating 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 pressed along the spray nut 185 into
  • the fluid is pumped in the direction of the increasing outer diameter of the injection 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 magnet 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 radially supported.
  • 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 empty without contact during normal operation of the vacuum pump 111 and only comes into contact with the rotor 149 when there is an excessive radial deflection relative to the stator. engages 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, ie in the motor compartment 137, the vacuum pressure prevails at least approximately as that produced 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.
  • turbomolecular pump 111 is largely identical to the one previously mentioned with reference to the Figs. 1 to 5 designed turbomolecular pump 111, which is why the basic structure of the turbomolecular pump 111 according to Fig.6 to the above description of the turbomolecular pump 111 according to the Figs. 1 to 5 Compared to the previous one with reference to the Figs. 1 to 5
  • the turbomolecular pump 111 described in Fig.6 additionally has a towing gas connection 225, the position and function of which will be discussed in more detail below.
  • the previously described turbomolecular pump 111 has a flood inlet 133 which opens into the Holweck pump stage of the pump 111.
  • a flood inlet 133 can also be provided in the area of the series-connected turbomolecular pump stages, in which case the flood inlet 133 is usually located in the downstream area of the pump mechanism which is formed by the series-connected turbomolecular pump stages.
  • the flood inlet 133 can be located, for example, in the area of the seventh pump stage.
  • the pump 111 can be flooded with air, for example, via such a flood inlet 133 after the pump 111 was taken out of service or the power supply to the electric motor 125 was interrupted.
  • the turbomolecular vacuum pump 111 has, in addition to or instead of the flood inlet 133, a carrier gas connection which is connected to the Fig.6 is identified purely schematically with the reference symbol "225".
  • the carrier gas connection 225 is a housing opening through which a carrier gas can be introduced into the pump mechanism formed by the turbomolecular pump stages.
  • the housing opening 227 of the carrier gas connection 225 can be closed, for example, with a screw cap (not shown here), which can be removed if necessary in order to be able to connect a supply line to the carrier gas connection 225, via which a carrier gas can be supplied to the carrier gas connection 225.
  • a flow control valve (not shown here) can be connected to the housing opening 227 of the carrier gas connection 225, the flow cross-section of which can be continuously changed in order to be able to continuously adjust and in particular regulate the amount of carrier gas supplied to the carrier gas connection 225.
  • M ⁇ N + 1 / 2 ⁇ .
  • the nomenclature is chosen such that the turbomolecular pump stage closest to the pump inlet 115 is referred to as the first and the turbomolecular pump stage closest to the pump outlet 117 is referred to as the Nth pump stage, with the individual turbomolecular pump stages from the first to the Nth being numbered consecutively with whole numbers in the direction of the pump outlet 117.
  • the carrier gas connection thus opens upstream of the sixth turbomolecular pump stage into the pump mechanism formed by the turbomolecular pump stages. If the turbomolecular pump has However, if, for example, the pumping system has eight turbomolecular pump stages, the carrier gas connection 225 opens upstream of the fifth turbomolecular pump stage into the pump mechanism formed by the turbomolecular pump stages.
  • the carrier gas connection 225 should in any case be provided downstream of the first turbomolecular pump stage, preferably downstream of the second turbomolecular pump stage, in order to prevent a backflow of the carrier gas in the direction of the pump inlet 115.
  • a carrier gas is not introduced into the pump mechanism via the carrier gas connection 225 only after the pump has been switched off; rather, the invention provides that carrier gas is introduced into the pump mechanism via the carrier gas connection 225 during operation of the turbomolecular pump 111 and thus during the conveyance of process gas from the pump inlet 115 to the pump outlet 117.
  • the carrier gas is introduced into the pump mechanism while the electric motor 125 is energized.
  • the carrier gas is thus introduced into the pump mechanism via the carrier gas connection 225 during the normal pumping operation of the turbomolecular pump 111.
  • This normal pumping operation can be defined as a time window during which the turbomolecular vacuum pump 111 is continuously operated at at least 75% of its maximum permissible power and/or at at least 75% of its maximum permissible speed.
  • the carrier gas is introduced into the pump mechanism through the carrier gas connection 225 during at least 50% of the time of the time window defined in this way.
  • the carrier gas is continuously introduced into the pump mechanism over a period of at least one hour during the conveyance of process gas, in particular over a period of 10 hours and preferably over a period of more than 24 hours.
  • the carrier gas introduced via the carrier gas connection 225 entrains or drags the process gas conveyed from the pump inlet 115 to the pump outlet 117 and in particular prevents process gas from flowing back from the pump outlet 117 to the pump inlet 115.
  • the pressure at the pump inlet thus drops in the desired manner, so that the pumping capacity increases in the desired manner.
  • turbomolecular vacuum pump 111 has a Holweck pumping stage downstream of the turbomolecular pumping stages in the manner described above. However, like the flood inlet 133, this is optional and is not required to achieve the entraining gas effect according to the invention.
  • the turbomolecular vacuum pump 111 according to the invention can therefore have a Holweck pumping stage, but does not have to.
  • the top diagram line shows an operating state of the pump in which no gases were introduced into the pump mechanism via the flood inlet or the carrier gas connection.
  • the middle diagram line refers to an operating state during which nitrogen was introduced into the pump mechanism via the flood inlet in the area of the seventh turbomolecular pump stage while the pump was operating.
  • the bottom diagram line refers to an operating state of the pump in which nitrogen was introduced into the pump mechanism via the carrier gas connection in the area of the fourth turbomolecular pump stage.
  • the pump was operated during all three operating states in such a way that 1,000 sccm of hydrogen gas were pumped as process gas from the pump inlet 115 to the pump outlet 117.
  • the introduction of nitrogen gas through the flood inlet already results in a reduction in the pressure at the pump inlet compared to the operating condition in which no carrier gas is introduced into the pump mechanism according to the top line of the diagram.
  • the pump inlet pressure drops even further if nitrogen is introduced into the pump mechanism as a carrier gas not via the flood inlet in the area of the seventh turbomolecular pump stage, but via the carrier gas connection in the area of the fourth turbomolecular pump.
  • the pump was operated in such a way that it continuously delivers 1,000 sccm of H 2 , with 100 sccm of nitrogen being introduced into the pump mechanism via the flood inlet or the seal gas connection 225.
  • Tests have shown that at a ratio of around 10:1 (standard cubic centimetres of process gas per minute: standard cubic centimetres of carrier gas per minute), the previously described backflow problem can be reliably reduced and the pump's suction capacity can thus be increased without this being at the expense of the pump's power consumption.
  • the ratio of the amount of entraining gas introduced into the pump mechanism measured in standard cubic centimeters per minute (sccm) to the amount of process gas conveyed measured in standard cubic centimeters per minute (sccm) is 1:X, where 5 ⁇ X ⁇ 15, where the ratio of the amount of entraining gas introduced into the pump mechanism to the amount of process gas conveyed is constant during the conveying of process gas.

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Claims (10)

  1. Procédé de fonctionnement d'une pompe à vide moléculaire (111) comprenant un carter (119) destiné à recevoir un mécanisme de pompage entraîné par un arbre de rotor (153) au moyen d'un moteur électrique pour transporter un gaz de traitement d'une entrée de pompe (115) vers une sortie de pompe (117),
    dans lequel
    le mécanisme de pompage comprend, entre l'entrée de pompe (115) et la sortie de pompe (117), une pluralité de N étages de pompage connectés en série de manière à pomper, l'étage de pompage le plus proche de l'entrée de pompe (115) étant le premier étage de pompage, et l'étage de pompage le plus proche de la sortie de pompe (117) étant le Nième étage de pompage, le carter (119) comprend un orifice de gaz porteur (225) qui débouche dans le mécanisme de pompage en amont d'un étage de pompage M, où M = ⌈ N + 1 / 2 ⌉
    Figure imgb0016
    ;
    une quantité de gaz porteur est introduite dans le mécanisme de pompage à travers l'orifice de gaz porteur (225) pendant le transport du gaz de traitement de l'entrée de pompe (115) à la sortie de pompe (117) ;
    caractérisé en ce que
    la quantité de gaz porteur introduite dans le mécanisme de pompage, mesurée en centimètres cubes standard par minute (sccm), par rapport à la quantité de gaz de traitement transportée, mesurée en centimètres cubes standard par minute (sccm), présente le rapport 1 : X, avec 5 ≤ X ≤ 15, le rapport de la quantité de gaz porteur, introduite dans le mécanisme de pompage, sur la quantité de gaz de traitement transporté étant constant pendant le transport du gaz de traitement.
  2. Procédé selon la revendication 1,
    dans lequel le gaz porteur est introduit dans le mécanisme de pompage pendant que le moteur électrique est alimenté.
  3. Procédé selon la revendication 1 ou 2,
    dans lequel la quantité de gaz porteur introduite dans le mécanisme de pompage, mesurée en centimètres cubes standard par minute (sccm), par rapport à la quantité de gaz de traitement transporté, mesurée en centimètres cubes standard par minute (sccm), présente le rapport 1 : X, avec 9 ≤ X ≤ 11, en particulier avec X égal à 10 ou sensiblement égal à 10.
  4. Procédé selon l'une des revendications 1 à 3,
    dans lequel le procédé est mis en oeuvre en utilisant une pompe à vide moléculaire (111) comprenant un carter (119) destiné à recevoir un mécanisme de pompage entraîné par un arbre de rotor (153) pour transporter un gaz de traitement d'une entrée de pompe (115) vers une sortie de pompe (117),
    dans lequel
    le mécanisme de pompage comprend, entre l'entrée de pompe (115) et la sortie de pompe (117), une pluralité de N étages de pompage connectés en série de manière à pomper, l'étage de pompage le plus proche de l'entrée de pompe (115) étant le premier étage de pompage, et l'étage de pompage le plus proche de la sortie de pompe (117) étant le Nième étage de pompage, le carter (119) comprend un orifice de gaz porteur (225) qui débouche dans le mécanisme de pompage en amont d'un étage de pompage M, où M = ⌈ N + 1 / 2 ⌉
    Figure imgb0017
    , et
    le gaz porteur est introduit dans le mécanisme de pompage à travers l'orifice de gaz porteur (225).
  5. Procédé selon la revendication 4,
    dans lequel M = ⌈ N / 2 ⌉
    Figure imgb0018
    , et en outre N ≥ 4.
  6. Procédé selon la revendication 4,
    dans lequel M = ⌈ N / 2 ⌉ − 1
    Figure imgb0019
    , et en outre N ≥ 6.
  7. Procédé selon l'une des revendications 4 à 6,
    dans lequel la pompe à vide moléculaire (111) est une pompe à vide turbomoléculaire (111) comprenant une pluralité de N étages de pompage turbomoléculaire connectés en série de manière à pomper, dont chacun comprend un disque de rotor (155) fixé à l'arbre de rotor (153) et un disque de stator stationnaire (157).
  8. Procédé selon l'une des revendications 1 à 7,
    dans lequel on utilise comme gaz porteur un gaz présentant une masse molaire supérieure à celle du gaz de traitement, et il est en particulier prévu d'utiliser comme gaz porteur de l'azote et/ou de l'argon.
  9. Procédé selon l'une des revendications 1 à 8,
    dans lequel le gaz porteur est introduit en continu sur une période d'au moins une heure pendant le transport du gaz de traitement, en particulier sur une période d'au moins 10 heures, de préférence sur une période de plus de 24 heures.
  10. Procédé selon l'une des revendications 1 à 9,
    dans lequel le gaz porteur est introduit en continu pendant au moins 50 % du temps d'une fenêtre temporelle pendant laquelle la pompe à vide moléculaire (111) fonctionne en continu à au moins 75 % de sa puissance maximale admissible ou à au moins 75 % de sa vitesse maximale admissible.
EP22193499.5A 2022-09-01 2022-09-01 Procédé permettant de faire fonctionner une pompe à vide moléculaire pour obtenir une puissance d'aspiration améliorée Active EP4108931B1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP22193499.5A EP4108931B1 (fr) 2022-09-01 2022-09-01 Procédé permettant de faire fonctionner une pompe à vide moléculaire pour obtenir une puissance d'aspiration améliorée
JP2023072957A JP2024035054A (ja) 2022-09-01 2023-04-27 排気速度が改善された分子真空ポンプ及び改善された排気速度を達成するように分子真空ポンプを運転する方法

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Application Number Priority Date Filing Date Title
EP22193499.5A EP4108931B1 (fr) 2022-09-01 2022-09-01 Procédé permettant de faire fonctionner une pompe à vide moléculaire pour obtenir une puissance d'aspiration améliorée

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EP4108931B1 true EP4108931B1 (fr) 2024-06-26

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Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2507430C2 (de) * 1975-02-21 1985-04-04 Franz-Josef Dipl.-Phys. Dr. 5300 Bonn Schittko Molekularvakuumpumpe mit hohem Kompressionsverhältnis für leichte Moleküle
JPH01277698A (ja) * 1988-04-30 1989-11-08 Nippon Ferrofluidics Kk 複合型真空ポンプ
JP2808470B2 (ja) * 1990-02-06 1998-10-08 日本原子力研究所 真空ポンプ
JP3038432B2 (ja) * 1998-07-21 2000-05-08 セイコー精機株式会社 真空ポンプ及び真空装置
EP3438460B1 (fr) * 2017-08-04 2024-03-20 Pfeiffer Vacuum Gmbh Pompe à vide

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EP4108931A1 (fr) 2022-12-28

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