JP2017020502A - Split flow vacuum pump and vacuum system having split flow vacuum pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a split flow vacuum pump capable of increasing a number of inlets without increasing a number of disposed pump stages.SOLUTION: A split flow vacuum pump has at least three radial inlets and at least four pump stages, where at least one pump stage is formed as a turbo molecular pump stage, and at least three inlets are formed as main inlets and axially disposed between the pump stages. Additionally, at least one radial sub-inlet (27, 28, 52) is disposed, and the sub-inlet is disposed in a region of the at least one turbo molecular pump stage (21, 22, 44, 45, 46).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vacuum pump in the form of a split flow pump.

  So-called split flow pumps are used in practice, for example, to evacuate multiple chambers of a mass spectrometry system simultaneously. With split flow vacuum pumps, it is possible to dispense with a pump system consisting of a plurality of individual pumps, and evacuation of a plurality of chambers can be performed with a single pump.

  Split flow vacuum pumps have the advantage of requiring only a small space requirement for a vacuum system. The split flow vacuum pump is used not only in the analysis apparatus but also in, for example, a leak search apparatus. The analysis principle likewise relates to a mass spectrometer (German: Massenspectrometrie).

  A turbomolecular pump is known from US Pat. No. 6,057,836 having a plurality of suction connectors, each of which is connected to one vacuum chamber of a device, for example a mass spectrometer. The suction connector directs the gas to different locations spaced apart in the axial direction of the rotor. A plurality of so-called rotor stator packets are provided along the rotor shaft. Each of these compresses the gas. The high vacuum side stator packet generates a pressure ratio between its inlet and its outlet. The inlet is connected to the first vacuum chamber. The outlet is connected to the inlet of the next rotor stator packet. In addition, this area between the two rotor stator packets is connected to a second vacuum chamber. Based on the pressure ratio generated by the first rotor stator packet and the poor conductance between the vacuum chambers (German: Leitwert), the pressure in both vacuum chambers is different. With a corresponding quantity of rotor stator packets, a plurality of vacuum chambers can be evacuated to different pressures. At this time, a rotor stator packet is attached to each suction connector. A very long rotor has been shown to be difficult to handle compared to the diameter. This is because the rotor is operated at a speed in the region of 10,000 revolutions per minute.

  Another variation of evacuating the device with multiple vacuum pumps is to provide each vacuum pump with a suitable flange. These are then connected to a suitable vacuum pump in the pressure zone. This method is not preferred due to the high cost for multiple vacuum pumps. Furthermore, there is a need for a compact device. However, these cannot be realized by a plurality of vacuum pumps.

  In multiple applications, the multiple vacuum chambers are provided in series and are connected to each other with low conductance by the hole (s). From one end of the row to the other end, the gas pressure inside the vacuum chamber decreases. The holes are formed so that the particle beam can travel through them and thus through the rows of vacuum chambers. The lowest pressure vacuum chamber often contains an analytical device, such as a mass spectrometer.

  From practice, split flow vacuum pumps with three or four radial inlets and at least four pump stages are known. The pump stage is usually a turbomolecular pump stage. These are often combined with other pump stages, for example Holbeck pump stages or Gede pump stages.

  In this application example, it is necessary to always provide a plurality of tappings in a split flow vacuum pump having high suction performance. That is, the rotor disk packet quantity needs to be increased, which again leads to manufacturing technical difficulties, for example when the rotor disk is stacked on the rotor only from one side.

  A plurality of disk packets having a plurality of axial stoppers can be realized in a wave-like shape by forming a variation related to the inner diameter of the rotor disk (axial joint diameter (German: Wellenfutured messenger)). However, this means that there must be a plurality of different disks in the pump structure. These different discs are also expensive to manufacture.

German Patent Application Publication No. 43 31 589 A1

  The basis of the present invention resides in the technical problem of providing a split flow vacuum pump in which the number of inlets can be increased without increasing the number of pump stages provided. In addition, a split flow vacuum pump should be provided in which a large number of rotor disk packets can be realized on a single shaft with high manufacturing accuracy while reducing pre-manufactured variations of the rotor disk.

  Moreover, a split flow vacuum pump should be provided that is capable of thermally separating both ends of the vacuum pump. This means, for example, that one end of the vacuum pump is heated and at the same time the opposite end, for example with a bearing, should not be overheated.

  This technical problem is solved by a split flow vacuum pump having the features of claim 1 and / or the features of claim 8 and / or the features of claim 11.

  The split flow vacuum pump according to the invention has at least three radial inlets and at least four pump stages. In this case, at least one pump stage is formed as a turbomolecular pump stage. In this case, at least three inlets are formed as main inlets, which are provided between the pump stages in the axial direction. The split flow vacuum pump is distinguished in that it is additionally provided with at least one radial garment inlet, which is provided in the region of at least one turbomolecular pump stage.

  With the formation according to the invention of the vacuum pump, it is possible to additionally provide at least one sub-inlet in the main inlet. The main inlet is provided between the pump stages as is known from the prior art. What is new in the present invention is the provision of at least one additional inlet provided in the region of at least one turbomolecular pump stage. This means that so-called tapping, i.e. no inlet is provided between the turbomolecular pump stages, and tapping leads in the radial direction into the disk packet of at least one turbomolecular pump stage.

  This clearly achieves a lot of tapping, i.e. multiple inlets, with only one pump at a given axial structure length. According to the invention, it is possible to evacuate as many chambers as possible with a short axial length.

  The rotor can be formed in one-part or multi-part.

  According to an advantageous embodiment of the invention, the at least one secondary inlet has a central axis, which is provided between the first and last disks of at least one turbomolecular pump stage.

  This means that the secondary inlet leads between the disks of at least one turbomolecular pump stage disk packet. This creates a plurality of additional inlets in addition to the prior art inlets provided between the pump stages, so that a larger number of vacuum chambers can be evacuated. is there.

  According to another advantageous embodiment of the invention, the at least one sub-inlet is arranged between the two stator disks and / or between the two rotor disks of the at least one turbomolecular pump stage and / or between the stator disks and the rotor. It is intended that they are provided between the disks and / or that at least two secondary inlets are provided with a radial offset from one another. This means that the secondary inlet is provided between the disks of the stator packets, while the main inlet is provided between the stator packets.

  When multiple sub-inlets are provided, they can be offset from one another in the radial direction and provided at the same axial height of the rotor. The secondary inlet is in this case provided between the two rotor disks in the disk packet and is divided radially in the periphery. However, they can also be provided in one plane.

  According to another advantageous embodiment of the invention, the at least one secondary inlet is between two adjacent stator disks of at least one turbomolecular pump stage and / or between adjacent rotor disks and / or It is provided between the stator disk and the adjacent rotor disk. This means that the secondary inlet is chosen relatively small with respect to its diameter and is provided between the disks.

  Advantageously, it is intended that the suction performance of the at least one secondary inlet is lower than the suction performance of the main inlet.

  The secondary inlet is used to increase the tapping quantity of the multi-chamber system to be evacuated.

  The main inlet may have a relatively large cross section because there is a relatively large space between individual pump stages, i.e. between individual disk packets or other pump stages such as the Gede pump stage or the Holbeck pump stage. Is possible. The secondary inlet opens between the disks of the turbomolecular pump stage and has only a relatively small cross section for this reason.

  According to another advantageous embodiment of the invention, it is intended that n-1 sub-inlets are provided in n disks.

  This means that the quantity of secondary inlets is less than the quantity of disks. When a turbomolecular pump disk packet is formed from two disks, it is possible to provide a sub-inlet between both disks.

  However, it is also possible to provide a plurality of radial sub-inlets in the region of the turbomolecular pump stage. Similarly, in a plurality of turbomolecular pump stages, it is possible to provide one or more sub-inlets in any of these turbomolecular pump stages. Different turbomolecular pump stages can be formed with or without secondary inlets.

  Advantageously, in addition to at least one turbomolecular pump stage, at least one Holbeck pump stage and / or Ziegburn pump stage and / or Gede pump stage and / or side channel pump stage and / or thread groove It is intended that a pump stage is provided.

  A split flow pump typically consists of one or more turbomolecular pump stages and at least one other pump stage as described above.

  Depending on the combination of different pump stages, the pressure ratio in the chambers to be evacuated can be adjusted accordingly.

  It is possible to provide one main inlet between a plurality of pump stages, for example between two turbomolecular pump stages, and for example additionally one Holbeck pump stage. According to the invention, additionally, at least one further sub-inlet is provided in the region of the at least one turbomolecular pump stage.

  According to another advantageous embodiment of the invention, it is intended that the turbomolecular pump stage is formed from one or more rotor disks and / or from one or more stator disks.

  The pump stage usually consists of at least one stator disk and at least one rotor disk. Often, there are a plurality of stator disks and a plurality of rotor disks interleaved alternately. According to the invention, it is advantageously intended that n-1 sub-inlets are provided on n disks. For example, when a stator disk and a rotor disk forming a turbo molecular pump stage are provided, the inlet is provided between these disks.

  Another advantageous embodiment of the invention is that the stator disk and the adjacent rotor disk of the turbomolecular pump determine the axial length L, and that the distance between the two turbomolecular pumps is at least this length L. It is intended to be the same length.

  Thereby, it has been determined that at least one stator disk and / or rotor disk forms at least one turbomolecular pump stage (German: festgelegt). When the spacing between adjacent stator disks and / or adjacent rotor disks is large enough to exceed the length L, a new turbomolecular pump stage is started according to the invention. The inlet in this region between the turbomolecular pump stages is considered as the main inlet. The inlet itself in the region of the turbomolecular pump stage is considered a secondary inlet.

  In accordance with another embodiment of the invention, it is contemplated that the turbomolecular pump stage is formed from at least one rotor disk.

  The embodiment according to the invention related to the inlet is basically applicable to a turbo molecular pump.

  Advantageously, the pump stage consists of at least one rotor disk and at least one stator disk. In this case, the sub inlet is provided between the rotor disk and the stator disk.

  Another embodiment of the split flow vacuum pump according to the invention has at least two radial inlets, wherein the vacuum pump has a plurality of stator disks and a plurality of rotor disks provided on a shaft. Wherein at least two disc packets are provided on the shaft, wherein the shaft has at least two different outer diameters and the disc packet has an inner diameter adapted to the outer diameter. . The vacuum pump stands out in that the shaft has at least two regions with smaller diameters on both sides in the axial direction in addition to the region with the largest diameter.

  The embodiment according to the invention allows a large number of individual disk packets on the shaft. According to the invention, four or more disk packets can be provided in the rotor.

  The shaft has two regions with smaller diameters on each side in the axial direction in addition to the region with the largest diameter, so that at least one disk packet is provided in each region. Is possible. This uses the area with the largest diameter as a stopper and provides at least one disk packet on each side of the area with the slightly smaller diameter, the area with the largest diameter, followed in the axial direction. It is possible. Subsequent areas, which again have a slightly smaller diameter, can each be provided with at least one further disk packet. The area with the largest diameter is each used as a stopper for the disk packet. These are assembled in a region having a slightly smaller diameter. In this case, the shaft has two packets each from the left and right (German: aufgeschoben), so there are four packets with only two diameters, which are the rotor disk and the disk packet. There is an advantage that an extremely large number of the same members can be used.

  In the structure of a split flow vacuum pump, it is necessary to maintain extremely high accuracy during assembly. Since the stator disk packets are spaced apart from each other, and the rotor disk packets are also spaced apart from each other, it is meaningful to make a stopper on the shaft. The more stoppers are present, the less tolerance is required in the disk, and the gap between the stator disk and the rotor disk can be made smaller.

  When the stopper is omitted, the rotor disk must be manufactured accordingly and this means high production costs, or the spacing between the rotor disk and the stator disk is selected accordingly. So that manufacturing tolerances do not lead to collisions between the stator disk and the rotor disk.

  Each ring packet is preferably assembled to a stopper. This measure clearly increases the accuracy of the location of the incorporated disk packet.

  In accordance with a particularly preferred embodiment of the invention, the smaller diameter regions have the same diameter as a pair on each side of the largest diameter region. Thereby, it is also possible to assemble the same disk packet, i.e. a disk packet having the same diameter, on both sides of the region having the largest diameter in the first smaller diameter. The same is true for the area following this area with a further reduced diameter. With this measure, there is the possibility of assembling four disc packets (which need only have two diameters in terms of manufacturing). This allows many of the same components to be pre-assembled, which significantly reduces manufacturing costs.

  According to another advantageous embodiment of the invention, it is intended that the transition between regions having different diameters is formed as a stopper for the disk packet. This stopper ensures that the disk packets of the rotor disk are accurately positioned between the stator disks and that the manufacturing tolerances of the individual disk packets are not added over the entire length of the shaft. Yes.

  According to an advantageous embodiment of the invention, the shaft is intended for a pyramid-shaped object structure. In this case, the same disc packet can be provided on both sides of the shaft. Basically, the shaft can be formed with a step. It is also possible for the shaft to be at least partially tapered in a conical shape.

  Different shaft shapes, i.e., a stepped shape and a conical shape can be combined with each other.

  Another embodiment of the split flow vacuum pump according to the invention has a housing, a shaft rotatably supported in the housing, and a stator disk provided in the housing, the rotor disk being provided on the shaft. This split flow vacuum pump is characterized in that the housing has at least two housing regions which are formed thermally isolated or a reduced thermal connection is formed therebetween. Stands out. In vacuum pumps, it is often desirable to heat one side of the pump to achieve a better evacuation of the receiver. The opposite side of the pump (which is often the side on which the bearings are provided) is not heated in some cases, or even this side may even be cooled. This is to support the shaft without any obstacles.

  This means that some of the vacuum pump is exposed to very high temperatures while the opposite part of the vacuum pump needs to have a relatively low temperature.

  For this reason, it is intended to achieve thermal restriction between at least both housing areas.

  According to an advantageous embodiment of the invention, it is intended that at least two housing areas are connected by a housing part having a reduced wall thickness relative to the wall thickness of the two housing areas.

  This means that the wall region between both housing regions has a thinner cross section than the other housings. For this reason, the housing has, for example, a neck portion.

  According to another advantageous embodiment of the invention, it is intended that in the region of the housing part there is a reinforcement made of a material having a thermal conductivity lower than that of the housing. In particular, such a reinforcing part can be advantageously provided in the region having the neck part.

  Another advantageous embodiment of the invention contemplates that at least two housing regions are formed from two separate housing members and that at least one heat seal is provided between the housing members. doing. Advantageously, the seal has a poorer thermal conductivity than the housing. Advantageously, the seal can be made of glass and / or ceramic and / or plastic. This seal prevents heat transfer from the heated part of the housing to the cooled part.

  Advantageously, at least one hole and / or at least one groove is provided in the housing. Coils and / or cooling elements for heating the heating element and / or the housing are provided therein. With this device it is possible to heat the area of the housing that should have a correspondingly high temperature and to cool the area to be cooled of the housing.

  In order to achieve the final pressure as soon as possible, it is advantageous to heat the pump. It can be adjusted to the reference temperature for maximum heating of the pump and rotor. This reference temperature can be the temperature provided by the pump (this temperature is associated with a critical temperature such as, for example, a rotor or a bearing). Similarly, external sensors such as temperature sensors, pyrometers etc. can be used. For example, the rotor temperature can be directly measured by a pyrometer. Furthermore, additional water cooling or the like can be used to maximize the maximum reduced heating temperature.

  According to another advantageous embodiment of the invention, a vacuum system having at least one vacuum pump and at least one receiver is intended, in which a releasable connection is provided between the vacuum pump and the receiver. In this case, at least one elastomer seal is provided toward the environment side for sealing the connection portion, and at least one gap seal is provided in the vacuum side direction. This is striking in that at least one suction channel and / or at least one suction opening is provided between the elastomeric seal and the gap seal.

  This embodiment has the advantage that an elastomer seal is used at the environmental seal. This is preferably formed as an O-ring. Between the elastomeric seal and, for example, an ultra-high vacuum connector, at least one gap seal is used as the second sealing element. The surface of the receiver (chamber) and the surface of the pump housing are pressed together.

  An advantageous embodiment of the split flow vacuum pump according to the invention has at least two radial inlets, wherein the vacuum pump has a stator disk and a rotor disk mounted on the shaft In this case, the shaft is provided with at least one disc packet. This split flow vacuum pump is provided with at least two grooves and / or holes in the shaft in the radial direction, which are formed longer in the axial direction of the shaft than in the circumferential direction of the shaft, Alternatively, it is intended that the shaft has at least one neck in the axial direction.

  In longer split flow vacuum pumps with multiple inlets, the formal aspects of the rotor and in particular the rotor shaft (reaction, model Verhalten) are critical. Therefore, it is necessary to attempt to reduce the mass of the shaft and the associated weight while keeping the strength the same, especially in the radial direction.

  This is advantageously achieved by the shaft having grooves and / or holes. The grooves and / or holes are preferably a plurality of axial drillings, for example a plurality of turning slots in the shaft (German: Einfraesungen). Advantageously, the grooves and / or holes are provided in areas where no rotor disk is provided.

  According to a particularly advantageous embodiment of the invention, at least two grooves and / or holes are provided radially in the shaft. It is intended that the shaft remains rotationally symmetric and has no unbalance.

  According to another advantageous embodiment of the invention, it is intended that at least two grooves and / or holes form at least one ring and are provided in the shaft. This means that grooves and / or holes are provided in the area where no rotor disk or disk packet is provided, in particular distributed evenly around the circumference of the shaft.

  When there are a plurality of regions in the shaft where no rotor disk or disk packet is provided, these regions can each be provided with grooves and / or holes.

  Advantageously, the grooves and / or holes have a rectangular and / or conical tapered and / or conical and / or stepped relief cross section. Is intended. Different cross sections are conceivable in the formation of the grooves and / or holes. The form of the cross-sectional shape depends on each application scene.

  Another advantageous embodiment of the invention contemplates that the hole is formed as a through hole. In addition to the groove that is not provided up to the central axis of the shaft, it is also possible to provide a hole formed as a through hole in the shaft. That is, the different holes on the surface of the shaft are concentrated in the core region of the shaft.

  According to another advantageous embodiment of the invention, it is intended that the shaft is provided with a sleeve at least in the region of the groove or in the region of at least one neck.

  An advantageous embodiment of the invention contemplates a split flow vacuum pump having at least two radial inlets. In this case, the vacuum pump has a stator disk and a rotor disk provided on the shaft. At that time, the shaft is provided with at least one disk packet. This is distinguished by the fact that at least one sleeve is provided on the shaft.

  Since the natural vibration frequency of the rotor can be changed by the arrangement of the sleeve on the shaft, the rotor does not have to be operated in the region of the natural vibration frequency. This also allows the mounting force to be reduced by a lighter rotor under the same or higher bending natural frequency.

  Moreover, it is possible to produce a high bending strength outer diameter without increasing the starting material of the rotor shaft. This can further reduce costs.

  Embodiments of the invention contemplate that the sleeve has a ring at at least one end. By means of the ring, the sleeve can be provided, for example, at a tapered shaft end. However, it is also possible in principle to provide the sleeve tightly on the shaft, for example on a certain outer diameter of the shaft.

  According to an advantageous embodiment of the invention, a sleeve is provided on the shaft, at least in the region of the groove and / or hole and / or at least one neck. By providing a sleeve in the region of the groove and / or hole and / or at least one neck, the strength of the rotor shaft is increased. In particular, the neck portion leads to losing the strength of the shaft. This can be ensured by the sleeve.

  Another advantageous embodiment of the invention contemplates that at least one sleeve is provided at the end of at least one shaft in a tapered region.

  The shaft end is usually tapered so as to be provided in a bearing, for example a ball bearing or a magnet bearing.

  The sleeve contributes to increasing the strength of the shaft.

  According to a preferred embodiment of the invention, it is intended that at least one sleeve is supported on the shaft on one side and on at least one carrier ring on the opposite side. When the shaft has, for example, a step-shaped longitudinal section, i.e. when it is tapered in a step shape, the sleeve can be provided in the region of two adjacent steps. The sleeve with the largest diameter can have the sleeve mounted directly on the shaft. In the step having a smaller diameter, the sleeve rests on at least one carrier ring.

  A particularly advantageous embodiment of the invention contemplates that at least one magnet ring of the magnet bearing is provided between the region of the shaft carrying the sleeve and at least one carrier ring. As a result, it is possible to reinforce the shaft at the end of the shaft, and to provide a magnet ring that is provided at a smaller diameter of the shaft and thus is inexpensive.

  Another advantageous embodiment of the invention contemplates that at least one sleeve is provided by solid material in the region of the shaft. With this embodiment, it is possible to change the natural vibration frequency of the rotor so that the rotor is not operated in the region of the natural vibration frequency.

  A modified advantageous embodiment of the invention contemplates that at least one sleeve is provided between the shaft elements in a region free of the rotor shaft. In this case, the shaft is formed as a divided shaft, and the sleeve connects a plurality of shaft elements. This clearly reduces the weight of the rotor shaft, which favors the formal aspect of the shaft.

  Another advantageous embodiment of the invention contemplates that at least one hole is provided in the sleeve. The hole is advantageously provided in the region of the groove and / or hole and / or neck. In the area of the vacuum pump, there should be no intermediate space filled with gas during evacuation. This is because the gas-filled intermediate space is evacuated during the evacuation process and this does not achieve the ultimate pressure of the pump that is inherently achievable.

  At least one sleeve is preferably made of metal. Aluminum, titanium or stainless steel can be selected as the metal. The at least one sleeve can be made of a composite material having carbon fibers, such as carbon fiber reinforced plastic. There is also the possibility of using a combination of a material made of metal and a composite material with carbon fibers.

  Advantageously, the axial dimension of the sleeve is greater than its outer diameter. According to this embodiment, the sleeve contributes best to improving the strength of the shaft.

  At least one sleeve is formed at the motor end of the rotor so as to be fixed to the rotor shaft before and after the motor magnet. As a result, it is possible to form a magnet ring having a smaller diameter, thereby reducing the cost. In the high vacuum direction, at least one sleeve can be mounted on the rotor shaft and in the direction of the bearing end can be connected to the shaft, for example by a ring.

  When the rotor is to be reinforced between two disc packets, it can likewise be provided with a sleeve according to the invention. This sleeve can be provided on a solid shaft. The connection between the solid shaft and the sleeve can be for example shrink, pressed and / or glued or other fixed form.

  Furthermore, the sleeve can be provided in the region of the shaft with at least one neck, or at least one contraction (German: Eindrehung) and / or grooves and / or holes. Due to the reduced mass which does not contribute much to the strength at the small diameter of the rotor, the natural frequency of the rotor is increased by the sleeve. In doing so, it is also positive that the mounting force is reduced in this way and, for example, in some cases when using permanent magnet bearings, the ring magnet pair can be omitted to reduce costs. It is.

  When the rotor disk is assembled in front of at least one sleeve in the assembly direction, the rotor disk mating sheet can be provided on an outer diameter that is smaller than the outer diameter of the sleeve. If this is not the case, the bundling portion of the rotor disk (with the rotor blades around it) is too weak for a combined diameter that is too large, which ensures that the rotor disk is no longer fixed to the rotor during operation This is advantageous when it will not be done.

  Moreover, it is possible to produce an outer diameter with a large bending strength without the need to increase the starting material of the rotor shaft, thereby reducing costs.

  According to an advantageous embodiment of the invention, an additional pump structure is provided on the outer side on the sleeve. The pump structure can be, for example, a turbo structure, a cross channel structure, a thread groove structure, or a Holbeck structure, or a combination of these structures.

  When at least one ring is provided on the sleeve, it can be provided on one or both, preferably at the end of the sleeve. The ring can be fixedly provided on the sleeve. There is also the possibility of forming at least one ring integrally with the sleeve. The ring is formed in the sleeve as an inner ring.

  The sleeve is used to increase strength. In particular, in the region of the neck, i.e. in the region where the shaft has a smaller diameter than the diameter where the rotor disk and / or rotor packet is provided, a sleeve can be provided to increase the strength. A plurality of holes can be provided in the sleeve. The hollow space in the shaft covered by the sleeve can be evacuated.

  The sleeve is advantageously made of a material having an elastic module and density greater than the elastic module and density toothache of the shaft.

  Another advantageous embodiment of the invention contemplates a split flow vacuum pump having at least two radial inlets. In this case, the vacuum pump has a stator disk and a rotor disk provided on the shaft. In this case, at least one disc packet is provided on the shaft, which is intended to have an internal hole provided along the longitudinal axis.

  This measure clearly reduces the weight of the shaft. However, strength, particularly radial strength, is maintained. This measure clearly improves the formal aspect of the rotor.

  According to another particularly advantageous embodiment of the invention, the shaft end (in which an internal hole is provided) does not have an inner bearing pivot (German: Lagerzapfen) in cross-section (German: topffermig) ) Is intended to be formed. By omitting the internal bearing pivot, an internal hole can be provided in the shaft end described above.

  A pump having the features of claims 1 to 10 can have the features of claims 11 to 20 individually or in combination.

  A pump having the features of claims 11 to 13 can have the features of claims 1 to 10 and 14 to 20 individually or in combination.

  A pump having the features of claims 14 to 19 can have the features of claims 1 to 13 individually or in combination.

  Additional features and advantages of the present invention will occur based on the accompanying drawings. In the drawings, several embodiments of a vacuum pump according to the invention are shown by way of example only.

Longitudinal sectional view of a device having a vacuum pump according to the invention Simplified view of a rotor with a disk packet having a primary inlet and a secondary inlet Longitudinal section of split flow vacuum pump Principle diagram of a rotor with a rotor disk provided in the rotor Longitudinal section of shaft tightly fitted with rotor disk Cross section of rotor shaft Principle diagram of rotor of split flow vacuum pump according to prior art Modified example Vacuum pump in perspective view with vacuum connector Longitudinal section of a modified embodiment of the shaft Longitudinal section of rotor with sleeve at shaft end Details of FIG. Longitudinal section of rotor with sleeve between disc packets Longitudinal section of a rotor with a sleeve between disk packets according to a modified embodiment Longitudinal cross section of rotor with neck Longitudinal section of a rotor with a disk packet tube sleeve and a split rotor shaft Longitudinal section of the shaft end of the rotor with internal holes Cross-section of sleeve with pumping structure Cross-section of a modified embodiment of a sleeve having a pumping structure Modified embodiment of a rotor with two secondary inlets Modified embodiment of a pump with two secondary inlets Modified embodiment having a rotor disk with ties

  FIG. 1 shows a vacuum pump 1. This vacuum pump is formed as a so-called split flow vacuum pump. The vacuum pump 1 is connected to a multi-chamber vacuum device 2. The multi-vacuum device 2 has four chambers 3, 4, 5 and 6. These should be evacuated by the vacuum pump 1. The gas pressure in the chambers 3, 4, 5, 6 increases in this order. The chambers 3, 4, 5, and 6 are separated from each other by separation walls 7, 8, and 9. At that time, the holes 9, 10, 11 form a connection part. These holes 9, 10, 11 are provided and dimensioned, for example, so that the particle beam can travel through all the chambers 3, 4, 5, 6. In particular, the first separation wall 7 separates the first chamber 3 and the second chamber 4 from each other, while the second separation wall 8 separates the second chamber 4 and the third chamber 5; A third separation wall 9 separates the third chamber 5 from the fourth chamber 6. Dashed arrows in FIG. 1 represent gas flow.

  The vacuum pump 1 has a shaft 13. This carries the rotor disks 14 to 19. Rotor disks 14 to 18 are in an intervening state with stator disk 20. The rotor disks 14, 15, and 16 form a first disk packet 21, and the rotor disks 17 to 19 form a second disk packet 22. The disk packet 22 forms a high vacuum side rotor stator packet together with the stator 20. The disk packet 21 together with the stator disk 20 forms a rotor stator packet on the intermediate vacuum side. The wings in both packets are then fixed to or formed integrally with the carrier ring on the stator side as well as on the rotor side, as is known in the prior art. A first gas inlet 23 is present in front of the rotor stator packet on the high vacuum side, and a second gas inlet 24 is present in front of the rotor stator packet on the pre-vacuum side.

  From the multi-chamber vacuum device, the first main inlet 23 leads into the vacuum pump 1. A second main inlet 24 communicates from the second chamber 4 into the vacuum pump 1. Another main inlet 25 from the vacuum chamber 5 leads into the vacuum pump 1 and another main inlet 26 leads from the vacuum chamber 6 into the vacuum pump 1.

  The main inlets 23, 24, 25, 26 are provided between the turbomolecular pump stages 21, 22.

  A first sub-inlet 27 is provided in the region of the turbo molecular pump stage 22. This leads from the vacuum chamber 5 into the vacuum pump 1. In addition, another sub-inlet 28 in the region of the turbomolecular pump stage 21 leads from the vacuum chamber 6 into the vacuum pump 1.

  Therefore, the quantity of inlets is increased by the auxiliary inlets 27 and 28. The sub-inlets 27 and 29 are provided in the region of the turbo molecular pump stages 21 and 22.

  The rotor shaft 13 has a plurality of regions having different diameters.

  The first region 29 is a region having the largest diameter. Two members 30 and 31 having a smaller diameter are connected to both sides of the shaft 13. To this, individually, the regions 32, 33 having a smaller diameter of the shaft 13 are connected. No rotor disk is provided in the largest diameter region 29 of the shaft 13. A rotor disk 16 is provided in the region 30. This rotor disk is clearly fixed locally by a stopper 34 (formed by a stepped node between the regions 29 and 30).

  The same is true for the rotor disk 15 which is fixed between the regions 30 and 32 by the stopper 35.

  Similarly, this is also true for the rotor disk 17 fixed to the shaft 13 by the stopper 36 and the rotor disk 18 fixed to the shaft 13 by the stopper 37. One spacer sleeve 38 is provided between the rotor disks 14 and 15 and the rotor disks 18 and 19. Since the rotor disks 14 to 19 are accurately arranged on the shaft 13 by the stoppers 34 to 37, a narrow gap can be formed between the rotor disks 14 to 19 and the stator disk 20.

  Another advantage of the present invention is that the rotor disks 14 to 19 can be accurately placed on the shaft, thereby forming a very small gap. Thereby, the pump performance of the vacuum pump 1 is enhanced. With the use of four identical parts, the pump has a cost advantage in manufacturing. In this embodiment, two rotor disk packets each having the same inner diameter are provided on both sides of the region 29 of the shaft 13 having the largest diameter.

  Another advantageous embodiment of the invention is an embodiment in which a plurality of grooves 39, 40 are provided in the region of the largest diameter 29, which reduce the mass of the shaft. Since the split flow vacuum pump has a very long structural length, the formal aspects of the rotor and especially the rotor shaft are important. For several reasons, according to the present invention, the mass and thus the weight of the shaft is also reduced with the same strength.

  The vacuum pump 1 has a housing 41. In order to reduce heat transfer between the high vacuum side and the pre-vacuum side of the housing 41, the housing 41 has a neck portion 42. This neck portion reduces thermal conductivity. In the region of the neck portion 42, a reinforcing portion (not shown) is additionally provided. The housing can also be divided and formed in the region of the neck 42 and a heat seal can be provided between both members of the housing.

  The shaft 13 is supported on one side by a magnet support portion 43. A counter support 43b is provided in the holder 43a, which is simply represented. The bearing is not shown on the other side. The bearing part on the side not shown can be, for example, an oil lubricated ball bearing part.

  In FIG. 1, only turbomolecular pump stages 21 and 22 are represented.

  In addition to the turbomolecular pump stage, there is also the possibility of providing a Holbeck pump stage and / or Ziegburn pump stage and / or Gede pump stage and / or side channel pump stage and / or threaded pump stage.

  The rotor disk 15 and the stator disk 20 have an axial length L when viewed in the axial direction. The spacing between the turbomolecular pump stages 21, 22 is greater than the length L.

  FIG. 2 shows the shaft 13 with the rotor disk packets 44, 45, 46. These form a stator disk packet (not shown) and turbomolecular pump stages 44, 45, 46. The gas flow is represented by arrows 47.

  Arrow 48 represents the gas flow supplied to the turbomolecular pump stages 45, 46 from the two main inlets 24, 25. An arrow 49 represents the gas flow supplied to the pump system from the two sub-inlets 27, 29 in the region of the turbomolecular pump stages 44, 45.

  The sub-inlets 27 and 29 are provided in the region of the turbo molecular pump stages 44 and 45, while the main inlets 24 and 25 have their supply sections between the turbo molecular pump stages 44, 45 and 46.

  FIG. 3 shows the vacuum pump 1. This once again makes clear that it has turbomolecular pump stages 44, 45, 46, 49. The turbo molecular pump stages 44, 45, 46, 49 are composed of a rotor disk and a stator disk. These are set up to intervene with each other. In addition, main inlets 23, 24, 25, 26 are provided. These are provided before the pump stage 44 or between the pump stages 44, 45, 46, 49.

  The shaft 13 is supported by a magnet support portion 43 and a ball support portion 50. The ball support 50 is an oil lubricated ball support. The shaft 13 is driven by a motor 51.

  A sub-inlet 27 is provided in the region of the turbo molecular pump stage 44. A sub-inlet 28 is provided in the region of the turbo molecular pump stage 45, and a sub-inlet 52 is provided in the region of the turbo molecular pump stage 46.

  With this embodiment, the quantity of inlets is increased from four main inlets 23, 24, 25, 26 to a total of seven inlets, that is, by three additional inlets 27, 28, 52 in addition.

  FIG. 4 shows a partial view of the shaft 12. The shaft 13 has a region 29 having the largest diameter shown in FIG. 1, followed by regions 30 and 31 having smaller diameters, and subsequently regions 32 and 33 having smaller diameters. ing. Rotor disks 16 and 17 are provided in the areas 30 and 31. In the regions 32 and 33, rotor disks 15, 18, and 19 are provided. The rotor disks 15, 18, 19 have the same inner diameter. The rotor disks 16, 17 have the same inner diameter. Thus, it is possible to configure a pump having a cost advantage by increasing the number of the same members.

  The difference in diameter between the regions 29 and 30 forms a stopper 34. A stopper 36 is provided between the regions 29 and 30. A stopper 35 is provided between the areas 30 and 32, and a stopper 37 is provided between the areas 31 and 33.

  The assembly direction of the disks 15 and 16 is indicated by an arrow A. The assembly direction of the rotor disks 17, 18, 19 is represented by an arrow B. M represents the central axis of the shaft 13. The shaft 13 and the rotor disks 15, 16, 17, 18, 19 are configured to be rotationally symmetric about the central axis M.

  FIG. 5 shows a shaft 13 with turbomolecular pump stages 21, 22. The shaft 13 has grooves 39 and 40 in a region where the rotor disks 14, 15, 16, 17, 18 and 19 are not provided.

  The formation of the groove having a greater extent in the axial direction than in the circumferential direction of the shaft 13 reduces the shaft mass, thus clearly improving the formal aspect of the rotor.

  FIG. 6 shows the different possibilities how the grooves 39, 40 can be formed.

  In FIG. 6, various embodiments of grooves are represented in the shaft 13. These grooves have the same cross section and are provided in the shaft 13 in a rotationally symmetrical manner. The implementation depicted in FIG. 6 is merely exemplary. In practice, each implementation is selected and placed rotationally symmetrically within the shaft.

  In FIG. 6, a groove 53 is shown. The groove has a rectangular cross section. The groove 54 is formed in a tapered shape in the direction of the central axis M in accordance with the second embodiment.

  The holes 55 are formed so that they form a plurality of through holes in the shaft 13. The hole 55 is concentrated at the point 56. The groove 57 has a cross section that is escaped in a step shape. The groove 58 is formed to expand in a conical shape in the direction of the central axis. This embodiment has the advantage that the shaft 13 maintains high strength. The outer radius material of the shaft 13 is stronger than the formal strength of the inner diameter material. For this reason, the groove 58 is a particularly advantageous embodiment.

  In addition to the groove, a sleeve 59 can also be provided. The sleeve 59 can be formed from a robust material.

  In addition, the shaft 13 has a neck portion (not shown). When providing a neck in the shaft 13, it is particularly advantageous to provide the sleeve 59 at least in the region of the neck.

  The sleeve 59 preferably has a plurality of holes 83 in the region of the groove. This hole is used so that the grooves 53, 54, 57, 58 and / or the hole 55 can be evacuated and thus they are not evacuated during evacuation of the receiver.

  FIG. 7 shows a shaft 13 having two turbomolecular pump stages 21, 22. These are provided in the housing 41 of the split flow pump. The housing 41 has an inlet 24.

  This indicates that, for the embodiment belonging to the prior art, the customer housing 60 has an inlet 61 which is formed offset in the radial direction with respect to the inlet 24. The axial lengths of the pump and customer chamber 60 do not match.

  In accordance with FIG. 8, a solution is represented how it is nevertheless possible to achieve the highest possible conductance. The housing 41 therefore has a web 62 in the region of the inlet 24. The formation of a web on which a stator disk (not shown) can be secured results in a larger cross section in the region of the inlet 24 and a higher conductance associated therewith.

  FIG. 9 has a vacuum pump 1 having vacuum connectors 72, 73, 75. The vacuum connector 72 has an elastomer seal 76 and a gap seal 77. A suction channel 78 is provided between the elastomer seal 76 and the gap seal 77. An intermediate suction portion 79 is provided in this. A suction opening 80 is provided in the vacuum connector 75. The intermediate suction part 79 communicates with the conduction hole 81. This is guided towards the intermediate stage 73. Since the connection channel 82 is provided for the sealing device of the vacuum connector 75, the vacuum connector 75 is similarly evacuated through the conduction hole 82 through the suction opening 80.

  FIG. 10 shows the shaft 13 having grooves 39 and 40. The grooves 39 and 40 are provided at a certain height in the axial direction. That is, they form a ring in the shaft 13. In addition, other grooves 63 and 64 are provided in other areas where the rotor disks 14 and 15 are not provided. These are likewise provided corresponding to each other in the axial direction and form a second ring of grooves. Further, two sleeves 59 are provided. These cover the grooves 39, 40, 63, 64. The sleeve 59 has a hole 83. The grooves 39, 40, 63 and 64 can be evacuated.

  11 and 12 show the rotor shaft 13. Rotor disks 21, 22, and 44 are provided on the rotor shaft. Since the rotor shaft 13 is formed in steps, the rotor disk packets 21, 22, and 44 are in contact with each one step and are thus positioned accurately.

  A sleeve 59 is provided at the end of the rotor shaft 13. The sleeve has one end 105 supported by the shaft 13 and the other end 106 supported by the carrier ring 103. The support ring 103 is further supported by the rotor shaft 13.

  The sleeve is thus supported on the motor magnet 101 on the front and rear on the rotor shaft 13. The sleeve 59 clearly increases the strength of the rotor, in particular the strength at the significantly tapered end 104. At the same time, the motor magnet 101, i.e. the magnet ring, can be manufactured with the usual relatively small diameter, which has a cost saving effect. If the shaft 13 is improved in strength by the shaft end 104 having a larger diameter, the motor magnet will need to be configured as well. This will work against costs.

  FIG. 13 shows another embodiment. According to FIG. 13, the rotor shaft 13 is reinforced by a sleeve 59 between the disk packets 21 and 22. The sleeve 59 is provided on the solid shaft 13. This can be fixed to the shaft 13 by shrinking, pressing or gluing. The sleeve 59 completely or almost completely fills the space between the disk packets 21 and 22. This completely fills the space between the disk packets 21, 22 and at the same time serves the function of a spacer sleeve such as the sleeve 38 of FIG.

  FIG. 14 shows a modified embodiment. In this embodiment, a sleeve 59 is disposed between the disk packets 21 and 22 on the rotor shaft 13. The sleeve 59 is provided with an interval with respect to the disk packet 21. The sleeve 59 is fixed on the shaft 13 made of solid material and reinforces the rotor shaft 13.

  FIG. 15 shows the rotor shaft 13. The rotor shaft has a neck portion 102. A sleeve 59 is provided in the region of the neck portion 102. The sleeve 59 has a hole 83. As a result, the neck portion 102 can be deaerated. When the receiver is evacuated by the vacuum pump, at the same time, an intermediate space in the area of the vacuum pump (such as the neck portion 102) is evacuated together. This is because otherwise it is not possible for the intermediate space 102 to be evacuated during the evacuation process and thus to achieve the final pressure of the vacuum pump.

  FIG. 16 shows the rotor shaft 13. The rotor shaft is formed as a divided rotor shaft having a plurality of shaft elements 107, 108. The shaft elements 107 and 108 are connected to each other by a sleeve 59. With this embodiment, the natural vibration frequency of the rotor is changed to allow for acceptable operation over a long period of time. The sleeve 59 again has a plurality of holes 83. Through these, the hollow space 109 between the shaft elements 107, 108 can be evacuated.

  In FIGS. 11 to 16, the same members are provided with reference numerals.

  FIG. 17 shows the shaft end 110 of the rotor shaft 13. The shaft 13 is supported by the magnet support 111. The magnet ring 112 of the magnet support 111 is provided on the shaft 13. A magnet ring 113 of the magnet support 111 is provided on the housing 114.

  In addition, a ball support 114 is provided. This is designed as an emergency bearing. The ball support 114 is preloaded by a spring 115. An internal hole 116 is provided in the shaft 13. This apparently reduces the weight of the shaft, thus changing the formal aspect of the rotor.

  FIG. 18 shows the sleeve 59. This sleeve has a carrier 117. This carrier is basically formed as a base portion of the cylinder side shape. A structured portion having a plurality of structural elements 118 is provided on the radially outer side of the carrier. The structural element 118 can be formed as a Holbeck pump stage or a cross-channel pump stage. The structural element 118 can have other pump stage structures.

  FIG. 19 shows the shaft 13. This is provided with a sleeve 59. The sleeve 59 carries a turbo molecular pump structure. This consists of a plurality of disks 119,120. A rotor disk 14 is provided in contact with the sleeve 59.

  Stator disks 121, 122, 123 intervene in the turbo molecular pump structure of the sleeve 59 formed by the disks 119, 120.

  The disks 14, 119 to 120 are represented only in a simplified manner.

  FIG. 20 tightens the rotor 126 which is represented only briefly with the rotor disks 14, 15, 16, 17. Two sub-inlets 27 and 28 are provided between the rotor disks 16 and 17. The sub-inlets 27 and 28 are spaced apart from each other in the radial direction, and both communicate with each other between the rotor disks 16 and 17.

  FIG. 21 shows a vacuum pump housing 60 having vacuum connectors 72, 73. Two sub-inlets 27 and 28 are provided, and these are arranged in one plane.

  FIG. 22 shows the rotor shaft 126. On top of this, rotor disks 14 and 15 are provided. A stator disk 20 is simply provided between the rotor disks 14 and 15. Each of the rotor disks 14 and 15 has one binding portion 127. The bundling portion 127 replaces the spacing sleeve 38 shown in FIG.

DESCRIPTION OF SYMBOLS 1 Vacuum pump 2 Multi-chamber vacuum apparatus 3 Chamber 4 Chamber 5 Chamber 6 Chamber 7 Separation wall 8 Separation wall 9 Separation wall 10 Hole part 11 Hole part 12 Hole part 13 Shaft 14 Rotor disk 15 Rotor disk 16 Rotor disk 17 Rotor disk 18 Rotor Disc 19 Rotor disc 20 Stator disc 21 Turbo molecular pump stage 22 with disc packet Turbo molecular pump stage 23 with disc packet 23 Main inlet 24 Main inlet 25 Main inlet 26 Main inlet 27 Sub inlet 28 Sub inlet 29 Shaft with the largest diameter 13 area 30 area 13 of shaft 13 having a smaller diameter area 31 area of shaft 13 having a smaller diameter Region 13 of shaft 13 Region of shaft 13 having the smallest diameter 34 Stopper 35 Stopper 36 Stopper 37 Stopper 38 Sleeve 39 Groove 40 Groove 41 Housing 42 Neck portion 43 Magnet bearing portion 43a Holder 43b Counter bearing portion 44 Turbo with rotor disk packet Molecular pump stage 45 Turbo molecular pump stage with rotor disk packet 46 Turbo molecular pump stage with rotor disk packet 47 Gas flow arrow 48 Gas flow arrow 49 Turbo molecular pump stage 50 Ball bearing part 51 Motor 52 Sub-inlet 53 Groove 54 Groove 55 hole 56 cutting point 57 groove 58 groove 59 sleeve 60 housing 61 inlet 62 web 72 vacuum connector 73 vacuum connector 75 vacuum connector 76 elastomer connector 77 Gap seal 78 Suction channel 79 Intermediate suction portion 80 Suction opening 81 Conduction hole 82 Connection portion 83 Hole portion 101 Motor magnet 102 Shaft neck portion 103 Ring 104 End portion 105 of rotor shaft 13 End portion 106 of sleeve 59 Sleeve 59 End portion 107 shaft element 108 shaft element 109 hollow space 110 shaft end portion 111 magnet support portion 112 magnet ring 113 magnet ring 114 ball support portion 115 spring 116 inner hole 117 carrier 118 structural element 119 rotor disk 120 rotor disk 121 stator disk 122 Stator disk 123 Stator disk 124 Sub-inlet 125 Sub-inlet 126 Rotor 127 Bundling part A Arrow B Arrow L Axial length M Center axis

Claims (15)

A split flow vacuum pump having at least three radial inlets and having at least four pump stages, wherein at least one pump stage is formed as a turbomolecular pump stage, and at least three inlets are the main inlets In split flow vacuum pumps, which are formed between the pump stages in the axial direction,
In addition, at least one radial sub-inlet (27, 28, 52) is provided, this sub-inlet being provided in the region of at least one turbomolecular pump stage (21, 22, 44, 45, 46). A split flow vacuum pump. At least one secondary inlet (27, 28, 52) has a central axis, and the central axis is at least the first and last discs (14 to 19) of the turbomolecular pump (21, 22, 44, 45, 46). 20). The vacuum pump according to claim 1, wherein the vacuum pump is provided between 20). At least one secondary inlet (27, 28, 52) is between the two stator disks (20) and / or between the two rotor disks (14 to 19) and / or between the stator disk (20) and the rotor disk (14). 3) and / or at least two secondary inlets (124, 125) are provided radially offset from one another. Vacuum pump. At least one sub-inlet (2) between two adjacent stator disks (20) and / or between two adjacent rotor disks (14 to 19) of at least one turbomolecular pump stage (1); 4. A vacuum pump according to claim 3, characterized in that it is provided between the stator disk (20) and the adjacent rotor disk (14 to 19). 5. The suction performance of at least one clothing inlet (27, 28, 52) is lower than the suction performance of the main inlet (23, 24, 25, 26). The vacuum pump described. 6. The vacuum pump according to claim 1, wherein n-1 sub-inlets (27, 28, 52) are provided in the n disks (14 to 19, 20). . The stator disk (20) and the adjacent rotor disks (14 to 19) of the turbo molecular pump stage (21, 22, 44, 45, 46) determine the axial length (L), and two turbo molecular pumps 7. The vacuum pump according to claim 1, wherein the distance between the stages (21, 22, 44, 45, 46) is at least as large as the length (L). . A split flow vacuum pump having at least two radial inlets, the vacuum pump having a plurality of stator disks and a plurality of rotor disks mounted on a shaft, wherein at least two disk packets are provided on the shaft A split flow vacuum pump in which the shaft has at least two different outer diameters and the disk packet has an inner diameter adapted to the outer diameter of the shaft;
In addition to the region (29) having the largest diameter, the shaft (13) has at least two regions (30, 32; 31, 33) each having a smaller diameter on both sides in the axial direction. Features split flow vacuum pump. 9. A vacuum pump according to claim 8, characterized in that the region (30, 32; 31, 33) having the smaller diameter has the same diameter as a pair on each side of the region having the largest diameter. Transitions (34, 35, 36, 37) between regions (29, 30, 31, 32, 33) having different diameters are formed as stoppers for disk packets (14 to 19) The vacuum pump according to claim 8 or 9. A split flow vacuum pump having a housing, a shaft rotatably provided in the housing, and a stator disk provided in the housing, wherein the shaft is provided with a plurality of rotor disks.
Split, characterized in that the housing (41) has at least two housing areas, which are formed in a thermally isolated manner or in which the thermal connection between them is reduced Flow vacuum pump. At least two housing areas are connected by a housing part (42) having a reduced wall thickness relative to the wall thickness of the two housing areas and / or within the area of the housing part (42), The vacuum pump according to claim 11, wherein a reinforcing portion made of a material having a thermal conductivity lower than that of the housing is provided. That at least two housing regions are formed from two separate housing members and that at least one heat seal is provided between the housing members, in particular if the seal is made of glass and / or ceramic and / or The vacuum pump according to claim 11, wherein the vacuum pump is made of plastic. At least one hole and / or at least one groove is provided in the housing (41), in which a heating element and / or a heating cartridge and / or a coil for heating the housing (41) and 14. A vacuum pump according to any one of claims 11 to 13, characterized in that a cooling element is provided. 15. A vacuum system comprising at least one vacuum pump and at least one receiver according to any one of claims 1 to 14, wherein a releasable connection is provided between the vacuum pump and the receiver, In a vacuum system in which at least one elastomeric seal (76) towards the atmosphere side for sealing and at least one gap seal (77) in the direction of the vacuum side is provided,
Vacuum system, characterized in that at least one suction channel and / or at least one suction opening (80) is provided between the elastomeric seal (76) and the gap seal (77).

Images