JP2015206362A - vacuum pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an improved vacuum pump in which the flow of gas opposite to a pumping direction is as small as possible.SOLUTION: The vacuum pump, in particular a turbo-molecular pump, comprises at least a pumping mechanism for pumping gas along a pump channel 10 extending from a main inlet to an outlet for gas. The pumping mechanism is configured such that a first pump effective portion 136 is provided upstream of a second pump effective portion 138 in the pumping mechanism, and has a higher compression capacity than that of the second pump effective portion 138, and/or such that the second pump effective portion 138 has a higher suction capacity than that of the first pump effective portion 136.

Description

  The present invention relates to vacuum pumps, particularly turbomolecular pumps, having at least one pumping mechanism for pumping gas along a pump channel extending from a main inlet to a gas outlet.

  A vacuum pump in which an intermediate inlet for gas opens into the pump channel is used, for example, in conjunction with a mass spectrometer to pump out various pressure chambers to different pressure levels. In this case, one of the pressure chambers can be pumped out via the main inlet and any other pressure chamber can be pumped out via a respective intermediate inlet. Such a vacuum pump is also called a spirit flow pump (German: Splitflow-Pumpen).

  However, problems arise with such pumps. Gas entering the pump channel via the intermediate inlet flows against the pumping direction from the main inlet to the outlet and thus leads to high gas friction and too high pressure. It is desirable to keep the gas flow entering the pump channel through the intermediate inlet opposite in the pumping direction as low as possible or completely prevented. Moreover, in order to keep the gas flow opposite to the pumping direction as low as possible or to prevent it completely, it would also be desirable for these in vacuum pumps to have no intermediate inlets.

German Patent Application Publication No. 10353034A1 German utility model No. 202009003880U1

  The object of the present invention is therefore to provide an improved vacuum pump in which the flow of gas opposite to the pumping direction is as low as possible.

  This problem is solved by the vacuum pump according to claim 1. Preferred embodiments and developments of the invention are described in the dependent claims.

  The problem is that, in particular, in the vacuum pump of the former described in the introduction, the pump mechanism is a part that performs the first pump action of the pump mechanism that is provided upstream of the part that performs the second pump action of the pump mechanism. However, it is formed so as to have a higher compression capacity than the part that performs the second pumping action, and / or the pump mechanism is higher in the part that performs the second pumping action than the part that performs the first pumping action It is solved by being formed to have a suction capability.

  According to an advantageous embodiment of the invention, at least one intermediate inlet and / or at least one extra opening opens into the pump channel, the first pumping part being the opening of the intermediate inlet And / or in the upstream of the excess opening flow, and in this case the second pumping part is present in the opening of the intermediate inlet and / or downstream of the excess opening flow.

  Within the framework of the present invention, the flow of gas entering the pump channel through the intermediate inlet or excess opening, opposite to the pumping direction from the main inlet to the outlet, flows into the intermediate inlet or excess opening. Downstream of the flow, can be prevented by being sucked away by a pumping mechanism having a high suction capacity and / or a high compression capacity of the first part with pumping action arranged in front of the opening It has been found that the backflow of gas opposite to the pumping direction can be suppressed or at least prevented.

  In so doing, suction capacity is seen as volumetric flow that can be transported through the cross section of the pump channel every time unit. In the vacuum pump according to the invention, the portion having the first pumping action is formed so as to convey a volume flow through the pump channel lower than the part having the second pumping action every time unit. Yes.

  The compression capacity is preferably related to the structural length. That is, it can be matched to the compression capacity for each structure length. Therefore, in the vacuum pump according to the invention, the pump mechanism is preferably formed such that the portion having the first pump action has a higher compression capacity for each structural length than the portion having the second pump action. Yes. The compression capacity is considered to be the compression ratio that can be achieved at each end located downstream of the flow by each pumping first or second part. Therefore, in the vacuum pump according to the present invention, the portion having the first pump action can achieve a higher compression ratio than the portion having the second pump action.

  According to a preferred embodiment of the present invention, the pump mechanism has a Holbeck pump mechanism. The Holbeck pump mechanism is a well-known pump mechanism that is used in turbomolecular pumps and is particularly efficient in the molecular flow region. The Holbeck pump mechanism has one or more Holbeck pump stages. They are connected in series or in parallel to each other and are usually post-connected to a turbomolecular pump stage within the turbomolecular pump.

  The Holbeck pump stage typically has a cylinder side-shaped stator element and a cylinder side-shaped rotor element as well. In this case, the side surface of the stator element and the side surface of the rotor element form a surface that generates the pumping effect of the Holbeck pump stage, and face each other while forming a narrow gap. This gap is called the Holbeck gap. Usually, in the side surface of the stator element, there are formed a plurality of webs that transition into a thread shape, and grooves that are disposed between the webs and also transition into a thread shape. These form a pump channel for the gas in the region of the Holbeck pump stage. The mutually facing sides of the rotor element are smoothly formed in the opposite direction.

  In principle, the web and the groove can also be provided on the side of the rotor element, and the side of the stator element can be formed smoothly. This is rarely seen in practice.

  The pumping action of the Holbeck pump stage is based on the fact that gas molecules to be transported are promoted inside the groove by the rotational movement of the rotor element and are thereby transported axially. In so doing, a web formed between the plurality of grooves seals the grooves and prevents or reduces backflow or outflow of gas molecules opposite in the pumping direction. The web and groove transitioning to the thread form forms a Holbeck thread. In that case, it is understood that the shape of the screw wire corresponds to a shape that forms only partial rotation of the screw wire.

  The stator element can in principle have a Holbeck thread also on the outer or inner side. The stator element may have surfaces that exert such a pumping effect on both sides. Any surface that produces a pumping effect can form a Holbeck pump stage with a side that produces the pumping effect of an essentially cylindrical rotor element that rotates relative to the stator element.

  Preferably, the opening of the surplus opening into the pump channel and / or the opening of the intermediate inlet is located inside the Holbeck pump stage of the Holbeck pump mechanism. The interior of the Holbeck pump stage has a high compression capacity in front of the opening by means of the corresponding formation of the intermediate inlet opening and / or the excess opening opening upstream or downstream of the Holbeck thread, and It can also be achieved that a high suction capacity placed behind the opening is realized by the Holbeck pump stage.

  Particularly preferably, the first pumping part is the part of the Holbeck pump stage located upstream of the flow of the opening and the second pumping part is the opening of the Holbeck pump stage. It is formed by the part located downstream of the flow. The Holbeck pump stage or the Holbeck stator of the pump stage thereby has a first pumping part with a high compressive capacity upstream of the flow of the opening and a second with a strong suction capacity downstream of the flow of the opening. It is possible to divide into two parts having the pumping action. This can be easily realized structurally.

  The opening of the intermediate inlet and / or the opening of the surplus opening is located in the pump channel between two holbeck pump stages of the holbeck pump mechanism, which are arranged in series and connected to enter each other in particular. Is particularly advantageous when In that case, the part having the first pump action is formed by the Holbeck pump stage located upstream of the flow of the opening, and the part having the second pump action is formed of the Holbeck pump stage located downstream of the flow of the opening. Can be done. The pump stage upstream of the first flow can thus be configured to have a higher compression capacity than the Holbeck pump stage downstream of the flow, which is later connected to the opening. The horbeck pump stage downstream of the flow can be configured such that its suction capacity is higher than that of the holbeck pump stage in front of the opening.

  The first pumping portion may have a first Holbeck thread and the second pumping portion may have a second Holbeck thread. Preferably, the first holbek thread is formed such that it achieves a higher compression capacity than the second holbek thread. The first Holbeck thread and the second Holbeck thread can be configured such that the second Holbeck thread achieves a higher suction capacity relative to the first Holbeck thread.

  Each HOLBEC thread is formed on the side of the rotor element cooperating with the stator element or stator element of each pumping part, and is formed by a web and a groove located between the web that transitions to the side in a thread shape. It can be formed. In so doing, the higher compressive capacity of the first Holbeck thread and / or the higher suction capacity of the second Holbeck thread are such that both Holbeck threads have the following parameters: groove quantity, groove or Achieved by differing in at least one of web slope angle, size of Holbeck gap between stator element and associated rotor element, groove depth, web height, groove width, and web width Can be done.

  A portion having a first pumping action having a first Holbeck thread and / or a part having a second pumping action having a second Holbeck thread by appropriate adjustment of at least one of the geometric parameters described above. Is positioned in front of the opening of the intermediate inlet and / or relative to the opening of the excess opening to provide a higher compression capacity and / or higher suction capacity after being placed in the opening Can be formed.

  The invention also relates to a vacuum device, in particular a leak locator or a mass spectrometer. It has a vacuum pump according to the invention that is integrated into the vacuum device or arranged in the vacuum device.

  The invention also relates to a vacuum pump, in particular a turbomolecular pump, having at least one pumping mechanism for pumping gas along a pump channel extending from the main inlet to the outlet for gas. In this case, a surplus opening for at least one intermediate inlet and / or gas is opened in the pump channel, the pump mechanism being upstream of the flow of the surplus opening and / or the opening of the intermediate inlet. The first pumping part of the pumping mechanism located is formed to have a higher compression capacity than the second pumping part of the pumping mechanism present downstream of the opening and / or In this case, the pump mechanism is formed such that the portion having the second pump action has a higher suction ability than the portion having the first pump action. The developments and embodiments mentioned here are correspondingly effective for the variations of the vacuum pump according to the invention described above.

  In the following, the invention will be described by way of example with reference to the accompanying drawings on the basis of advantageous embodiments. The diagram shows the following briefly.

Cross section of vacuum pump Perspective view of stator element of Holbeck pump stage Partial sectional view of one variation of the Holbeck pump mechanism Cross-sectional view of a variation of the Holbeck pump mechanism in FIG. Variation of Fig. 4A variation Cross-sectional partial view of another variation of the Holbeck pump mechanism Cross section of another vacuum pump FIG. 6 is a partial sectional view of the Holbeck pump stage FIG. 6 is a view of the outer surface of the Holbeck stator sleeve located radially outward of the Holbeck pump stage of the vacuum pump of FIG.

  The vacuum pump shown in FIG. 1 includes a pump inlet 70 surrounded by an inlet flange 68 and a plurality of pumps for conveying gas spanning the pump inlet 70 through the pump channel 10 to a pump outlet not shown in FIG. Has a stage. The vacuum pump has a stator having a static housing 72 and a rotor disposed in the housing 72. The rotor has a rotor shaft 12 that is rotatably supported about a rotation shaft 14.

  The vacuum pump is designed as a turbomolecular pump and has one pumping mechanism formed from a plurality of turbomolecular pump stages connected in series that perform the pumping action. The turbomolecular pump stage includes a plurality of turbomolecular rotor disks 16 connected to the rotor shaft 12 and a plurality of turbomolecular stators disposed between the rotor disks 16 in the axial direction and fixed in the housing 72. A disk 26 is provided. The stator disks 26 are held at desired axial intervals by spacer rings 36. The rotor disk 16 and the stator disk 26 have an axial pumping action in the direction of the arrow 58, that is, in the direction of the pump, in the suction area (German: Schoeffbererich) 50. The pump channel 10 then passes through a turbomolecular pump stage and further extends through a Holbeck pumping mechanism located behind the turbomolecular pump stage.

  The Holbeck pump mechanism, in the example shown, may have three Holbeck pump stages that are arranged radially inward of each other and connected in series to each other to perform a pumping action. The rotor-side portion of the Holbeck pump stage is fixed to a rotor hub 72 and a rotor hub 74 connected to the rotor shaft 12, and is supported by the two holbeck rotor sleeves 76, 78 having a cylinder side shape. Have Further, two holbek stator sleeves 80 and 82 having a cylinder side surface shape are provided. They are likewise oriented coaxially with respect to the axis of rotation 14 and are connected to enter each other in the radial direction.

  The pumping surface of the holbeck pump stage is formed by holbeck rotor sleeves 76 and 78 and a holbeck stator, respectively, by radial side surfaces facing each other while forming a narrow radial holbeck gap. Sleeves 80 and 82 are formed. In this case, each one of the pumping surfaces (in this case, that of the Holbeck rotor sleeve) is formed smoothly, and the opposite side surfaces of the Holbeck stator sleeves 80, 82 that produce the pumping effect are: It has a Holbeck thread having a plurality of grooves that move in the axial direction about the rotating shaft 14. Within this thread, gas is promoted by each rotation of the rotor sleeves 76, 78, thereby pumping.

  In the region of each Holbeck pump stage, the grooves essentially form a pump channel for the gas to be pumped. The Holbeck pump stage then provides pumping action, in particular based on the Holbeck thread, and further carries the gas carried by the turbomolecular pump stage along the pump channel to the outlet through the Holbeck pump stage.

  The rotatable bearing of the rotor shaft 12 is effected by a roller bearing 84 in the area of the pump outlet and a permanent magnet bearing 86 in the area of the pump inlet 70.

  The permanent magnet bearing 86 includes a rotor-side bearing half 88 and a stator-side bearing half 90. Each of them has a single ring stack composed of permanent magnet rings 92 and 94 stacked in the axial direction. At this time, the magnet rings 92 and 94 face each other while forming a radial bearing gap 96.

  An emergency or safety support 98 is provided in the magnet support 86. This is formed as an unlubricated roller bearing. During normal operation of the vacuum pump, the safety support 98 performs idling operation. This engages only when the rotor is over-radiated with respect to the stator, forming a radial stop for the rotor. This stopper prevents the structure on the rotor side from colliding with the structure on the stator side.

  In the region of the roller support portion 84, one conical splash nut 100 is provided on the rotor shaft 22. This has an outer diameter that increases towards the roller bearing 84. The splash nut 100 is in contact with a skimmer (German: Abstriefer) in the working medium reservoir. The working medium storage unit has a plurality of absorbent disks 102 containing working medium such as a lubricating medium. During operation, the working medium is transferred from the working medium reservoir to the rotating splash nut 100 via the skimmer by capillary action. And as a result of centrifugal force, it is conveyed toward the roller support part 84 in the direction of the outer diameter which becomes large along the splash nut 100, and exhibits a lubricating function there, for example.

  However, other types of bearings for the roller shaft 12 are also possible. For example, a five-axis active magnet bearing for the rotor shaft 12 can be provided.

  The vacuum pump has one drive motor 104 for rotationally driving the rotor. The rotor is formed by a rotor shaft 12. A control unit 106 drives the motor 104.

  The stator element shown in FIG. 2 can be used as the Holbeck stator sleeve 82 in the vacuum pump of FIG. The stator element basically has a basic Keio with a cylinder side shape and has three independent stator members. These members subdivide the stator element into three angular portions. The section surfaces of the individual stator members 108, 108 ′, 108 ″ are represented by reference numerals 110, 112 and 114 in FIG. 2 and run essentially parallel to the longitudinal axis 116 of the stator element. Thus, each stator member 108, 108 ′, 108 ″ forms one cylinder side element having a profile that is essentially perpendicular when viewed from its flat surface. The stator element, however, can also be formed in one piece.

  Each stator member 108, 108 ′, 108 ″ has a plurality of web portions 118, 118 ′, 118 ″ on its outer surface and its inner surface, respectively. These together form a plurality of webs that transition in the direction of the threaded longitudinal axis 116. These webs are formed on the inner and outer side faces of the stator element, and a plurality of grooves 120 are formed between them in the axial direction 116 of the thread shape. The web and groove 120 each form one holbek thread on the inner and outer sides of the stator element. This is suitable for forming a Holbeck pump stage with a rotor element (see Holbeck rotor sleeves 76, 78 in FIG. 1) that rotates relative to each side and is formed as a Holbeck cylinder. In this case, each rotor element has, in particular, one surface that produces a smooth pumping effect.

  Due to the segmentation of the stator elements, its manufacture is clearly simplified. This is because the individual stator members 108, 108 ′, 108 ″ are manufactured without undercut (German: hinterningungsfrei) and can be easily molded (deformed). The stator element can, however, also be manufactured in one piece. This is for example to cut out from a solid or hollow cylinder made of vacuum compatible metal or plastic.

  The preferred flow path 148 of gas pumped by the Holbeck pump stage transitions along the plurality of grooves 120 and is represented in FIG.

  In the vacuum pump according to the invention, in addition to the main inlet formed in the pump inlet 70, one intermediate inlet 122 can be provided. This intermediate inlet opens into the pump channel 10 (see FIGS. 3, 4A and 5).

  In the vacuum pump, the part that performs the first pumping action of the pump mechanism that is located upstream of the flow of the opening of the intermediate inlet 122 is higher than the part that performs the second pumping action that is located downstream of the flow of the opening. At least one pump mechanism is formed such that the portion having the compression capability and / or the portion having the second pump action has a higher suction ability than the portion having the first pump action. This can prevent or reduce the flow of gas through the intermediate inlet 122 opposite the pumping direction into the pump channel 10. This can improve the performance of the vacuum pump as a whole.

  The first or second pumping part located upstream or downstream of the flow means in particular the part or region of the pump mechanism located directly before and after the opening.

  In the variation of FIGS. 3A and 4A, the opening into the pump channel 10 of the intermediate inlet 122 is a Holbeck pump stage having an outer stator 126 and an inner rotor 128 cooperating with the stator 126. 124 is located inside.

  The stator 126 can be formed like the stator element described with reference to FIG. 2, and thereby can have a basic shape of a cylinder side shape. As shown in FIG. 3, the intermediate inlet 122 is in the form of a channel having a circular cross-section and passes through the stator 126 in a direction transverse to the direction of the longitudinal axis 116, and in this case, the hole It opens into a pump channel 10 that moves through the Beck pump stage. The channels forming the intermediate inlet 122 can alternatively have an oval or square cross section.

  In the Holbeck pump stage 126, the portion of the stator element 126, which is located upstream of the opening 134 with respect to the pump channel 10, forms a first pumping portion 136 and downstream of the opening 134. The portion of the stator 126 that is positioned forms a portion 138 that performs the second pumping action. As a result, the stator 126 exhibits a higher compression capability than the portion 138 performing the second pump action, and a portion 136 performing the first pump action and a portion 138 exhibiting the second pump action having a higher suction capability. It is divided into two.

  In order to achieve a higher compression capacity or higher suction capacity, the Holbeck threads 140, 142 formed on the pumping parts 136, 138 are different from each other. The first horbeck thread 140 on the inner side surface of the portion 136 having the first pumping action is formed by a plurality of webs 130 that transition into a threaded shape and a plurality of grooves 132 that are positioned therebetween. The second horbeck thread 142 provided on the inner side surface of the portion 138 having the second pumping action is formed by a plurality of webs 130 ′ transitioning to a thread shape and a plurality of grooves 132 ′ positioned therebetween. The

  The first Holbeck thread 140 has a narrower and flatter structure than the second Holbeck thread 142, which is open and has a rough and steep gradient structure. As shown in FIG. 3, each structure of the first or second Holbek thread 140, 142 has a plurality of grooves 132 that are narrower than a plurality of grooves 132 ′, and a plurality of webs 130 or a plurality of grooves 132. The slope is lower than the slope of the plurality of webs 130 ′ or the plurality of grooves 132 ′, the plurality of webs 130 is higher than the plurality of webs 130 ′, the plurality of grooves 132 is deeper than the plurality of grooves 132 ′, and Alternatively, this is achieved by the fact that the Holbeck gap in the first Holbeck thread 140 is smaller than the Holbeck gap in the second Holbeck thread 142.

  In that case, the gradient is intended to be similar in magnitude to the conventional thread gradient. Further, the Holbeck gap is intended to mean each distance between the front sides of the plurality of grooves 132 and 132 ′ facing inward in the radial direction with respect to the outer side surface of the Holbeck rotor sleeve 144.

  Due to the different construction of both Holbeck threads 140, 142, the first pumping portion 136 achieves a high compression capacity in the pump channel 10 in the region of the opening 134 and the second pumping action. The playing portion 138 achieves a high suction capacity in the region of the opening 134 of the pump channel 10. This can prevent or at least reduce undesired flow of the gas flowing in through the intermediate inlet opposite to the pumping direction in a simple and efficient manner. This is because the gas is “absorbed” by the second pumping portion 138 in the sense, or the high compressive capacity caused by the first pumping portion 136 is that of the gas opposite to the pumping direction. This is because it prevents inflow.

  In the variation described in connection with FIGS. 3 and 4A, the first pumping portion 136 having a high compression capacity is thus a portion of the Holbeck pump stage 124 located upstream of the opening 134 flow. On the other hand, a portion 138 having a high suction capability and having a second pumping action is formed from a portion of the Holbeck pump stage 124 located downstream of the flow of the opening 134.

  A holbeck pump stage 124 having a holbeck rotary sleeve 144 and having a rotor 128 located on the inside and rotatable about a longitudinal axis or axis of rotation 116 and a stator 126 located on the outside comprises: It can be used in the vacuum pump of FIG. 1 as a Holbeck pump stage, which, in particular with respect to the pump channel 10, is arranged after one or more turbomolecular pump stages and another Holbeck pump stage. In series.

  The vacuum pump can also be formed without an intermediate inlet. See variation in FIG. 4B. In this variation, the intermediate inlet 122 is not provided compared to the variation of FIG. 4A. In the variation of FIG. 4B, at least one pump mechanism and, in particular, a Holbeck pump stage located radially outward is a first pump mechanism located upstream of the flow of the second pumping part of the pump mechanism. The pumping portion has a higher compression capacity than the second pumping portion and / or the second pumping portion is higher in suction than the first pumping portion. It is formed to have the ability. This can prevent or at least reduce backflow of gas opposite the pumping direction during pump operation. The performance of the vacuum pump can thereby be improved as a whole.

  In the variation of FIG. 5, the opening 134 of the intermediate inlet 122 into the pump channel 10 is located between the first Holbeck pump stage 124 ′ and the second Holbeck pump stage 124 ″. Both pump stages 124 ′, 124 ″ are arranged in series and connected to enter each other. The pump channels 10 are thus each in the region of the opening 134 of the intermediate inlet 122 from the first Holbeck pump stage 124 ′ to the second Holbeck pump stage 124 ″, as suggested in FIG. And a 180 degree turning part in the rear passage (German: Nachgang) to the second Holbeck pump stage 124 '' as seen in the pumping direction 146.

  The first Holbeck pump stage 124 'has a cylinder 126-shaped stator 126'. Its inner side, together with the Holbeck rotor sleeve 144 of the rotor 128, forms the original surface that produces the pumping effect of the pump stage 124 '. In this case, as shown in FIG. 5, the first Holbeck thread 140 is provided on the inner side surface of the stator 126 '. The second Holbeck pump stage 124 "has a cylinder 126-shaped stator 126". Its outer side, together with the inner side of the Holbeck rotor sleeve 144, forms the surface that produces the original pumping effect of the second Holbeck pump stage 124 '', with the second Holbeck thread 142 being the stator 126 ″ is provided on the outer side surface.

  In the variation of FIG. 5, the first pumping portion is due to the first Holbeck pump stage 124 ′ and the second pumping portion is due to the second Holbeck pump stage 124 ″. It is formed. The first pumping part or the first Holbeck pump stage 124 'has a higher compression capacity than the second pumping part or the second Holbeck pump stage 124' 'whose suction capacity is higher. Have A higher compression capacity or a higher suction capacity can then be achieved, in particular, here again due to the structural differences of the first or second Holbeck threads 140, 142.

  The first Holbeck thread 140 has a narrower and flatter structure than the second Holbeck thread 142 which has an open, rough and steep structure.

  The structure of the first or second Holbeck thread 140, 142 is such that the groove 132 is narrower than the groove 132 ', the slope of the web 130 or groove 132 is lower than the slope of the web 130' or groove 132 '. The web 130 is higher than the web 130 ′, the groove 132 is deeper than the groove 132 ′, and / or the Holbeck gap in the first Holbeck thread 140 is greater than the Holbeck gap in the second Holbeck thread 142. It can be realized by being small.

  Due to the different construction of both Holbeck threads 140, 142, the part that performs the first pumping action achieves a high compression capacity in the pump channel 10 in the region of the opening 134 and the part that performs the second pumping action. Has a high suction capacity in the region of the opening 134 in the pump channel 10. This prevents or at least reduces undesired backflow of gas backflowing through the intermediate inlet 122, opposite the pumping direction, in a simple and efficient manner. This is because the part that performs the second pumping action sucks the gas in the pumping direction, and the part that performs the first pumping action greatly prevents the inflow of gas opposite to the pumping direction. is there.

  Both inwardly connected Holbeck pump stages 124 ', 124 "can be used in the vacuum pump of FIG. This can be used after the turbomolecular pump stage, particularly with respect to the pump channel 10.

  The vacuum pump shown in FIG. 6 is configured like the vacuum pump shown in FIG. Unlike the vacuum pump of FIG. 1, in the vacuum pump of FIG. 6, the Holbeck stator sleeve 80 located radially outward has a surplus channel (German: Flutkanal) 152 on its outer surface 150. This surplus channel connects a surplus channel inlet 154 provided in the pump housing 72 to two surplus openings 156. The surplus opening 156 runs at least essentially radially through the Holbeck stator sleeve 80 and opens into the Holbeck gap between the Holbeck stator sleeve 80 and the Holbeck rotor sleeve 76.

  The intermediate inlet 122 is typically used as an inlet for process gas pulled from the receiver by a vacuum pump, while the surplus channel inlet 154 is normally closed during pump operation. The surplus channel inlet 154 is normally opened only after the vacuum pump is shut off to ventilate the pump. Due to the ventilation of the pump, the rotor shaft 12 and the members arranged on it can be brought quickly to rest.

  The radially and outwardly located Holbeck pump stage formed by the Holbeck stator sleeve 80 and Holbeck rotor sleeve 76 has a first pumping part (this part is the flow of gas pumping through the Holbeck gap). With respect to the direction, it has a second pumping portion (located upstream of the flow of the opening of the surplus opening 156) (this portion is positioned downstream of the flow of the opening). In that case, the part which exhibits the first pump action has higher compression ability and lower suction ability than the part which exhibits the second pump action. This allows the gas flowing from the surplus opening 156 into the Holbeck gap to be pumped out in a better way in the intended flow direction during the ventilation of the vacuum pump. The gas flow from the surplus opening 156 to the pre-arranged turbomolecular pump stage is thereby reduced, especially with respect to the time when the rotor shaft 12 is still rotating at a high speed. Damage to the blades of the turbomolecular pump stage due to the gas flowing in at high rotation can be prevented thereby. At low speeds, the flowing gas is not harmful to the turbomolecular pump stage. As the rotational speed decreases, the pump effect acting on the first and second pumping parts is weakened, so that more gas entering through the excess opening 156 with the decreasing rotational speed becomes a turbomolecular pump. Flowing through the stage.

  An unrepresented variation of the vacuum pump has at least one extra opening 156 and an intermediate inlet 120 in the Holbeck gap of the Holbeck pump stage. At that time, the transition portion between the first pumping portion and the second pumping portion of the Holbeck pump stage is in the region of the opening of the intermediate inlet or the region of the opening of the excess opening. Is inside.

  In the described variations, the respective parts that perform the first pumping action have a higher compression capacity than the parts that perform the second pumping action whose suction capacity is higher. However, only the compression capacity of the part having the first pump action is higher than that of the part having the second pump action, or only the suction capacity of the part having the second pump action is only the first pump action. Variations that are higher than that of the part that acts are also conceivable.

10 Pump channel 12 Rotor shaft 14 Rotating shaft 16 Rotor disc 26 Stator disc 36 Spacer ring 50 Suction area 58 Arrow 68 Inlet flange 70 Pump inlet (main inlet)
72 Housing 74 Rotor hub 76, 78 Holbeck rotor sleeve 80, 82 Holbeck stator sleeve 84 Roller bearing part 86 Permanent magnet bearing part 88 Rotor side bearing half part 90 Stator side bearing half part 92, 94 Permanent magnet ring 96 Radius Directional bearing gap 98 Safety bearing 100 Splash nut 102 Absorbent disc 104 Drive motor 106 Control unit 108, 108 ', 108''Stator member 110 Partition surface 112 Partition surface 114 Partition surface 116 Longitudinal axes 118, 118' 118 ″ web portion 120 groove 122 intermediate inlet 124, 124 ′, 124 ″ Holbeck pump stage 126, 126 ′, 126 ″ stator 128 rotor 130, 130 ′ web 132, 132 ′ groove 134 opening 136 first Of the Part 138 performing the second pump action 140 first horbeck thread 142 second horbeck thread 144 holbeck rotor sleeve 146 pumping direction 148 flow path 150 outer 152 extra channel 154 extra channel inlet 156 Extra opening

Claims (13)

At least one pump mechanism (125, 124) for pumping gas along a pump channel (10) extending from a main inlet (70) to an outlet for gas, particularly a vacuum pump, particularly a turbomolecular pump. ', 124'')
The pump mechanism (124, 124 ′, 124 ″) is provided upstream of the flow of the second pumping portion (138) of the pump mechanism (124, 124 ′, 124 ″). , 124 ′, 124 ″) the first pumping portion (136) is configured to have a higher compression capacity than the second pumping portion (138) and / or
The pump mechanism (124, 124 ′, 124 ″) is formed such that the portion (138) performing the second pumping action has a higher suction ability than the portion (126) performing the first pumping action. A vacuum pump characterized by that. At least one intermediate inlet (122) and / or at least one extra opening (156) for the gas is open into the pump channel (10), the first pumping part (136) ) Are present upstream of the flow of the surplus opening 156) and / or the opening (134) of the intermediate inlet (122), and the second pumping portion (138) is present in the surplus opening (156). ) And / or downstream of the flow of the opening (134) of the intermediate inlet (122). 3. A vacuum pump according to claim 1 or 2, characterized in that the pump mechanism (124, 124 ', 124 ") comprises a Holbeck pump mechanism. The opening of the intermediate inlet (122) and / or the opening of the surplus opening (156) into the pump channel (10) is located inside the Holbeck pump stage (124) of the Holbeck pump mechanism. The vacuum pump according to claim 2 or 3, wherein The first pumping part (136) is formed by the part of the Holbeck pump stage (124) located upstream of the flow of the opening (134) and the second pumping part (138). The vacuum pump according to claim 4, characterized in that is formed by the part of the Holbeck pump stage (124) situated downstream of the flow of the opening (134). The two Holbeck pump stages of the Holbeck pump mechanism (in particular, the openings (134) of the intermediate inlet (122) and / or the openings of the surplus opening (156) are arranged in series and connected to enter one another. The vacuum pump according to claim 2, characterized in that it opens into the pump channel (10) between 124 ', 124' '). The part that performs the first pumping action is formed by the Holbeck pump stage (124 ′) located upstream of the flow of the opening (134), and the part that performs the second pumping action is downstream of the flow of the opening. 7. A vacuum pump according to claim 6, characterized in that it is formed by a Holbeck pump stage (124 '') located in The first pumping part (136) has a first horbeck thread (140) and the second pumping part (138) has a second holbeck thread (142). The vacuum pump according to any one of claims 1 to 7, wherein: The first horbeck thread (140) and the second holbeck thread (142) provide a higher compressive capacity of the first holbeck thread (140) relative to the second horbeck thread (142). The vacuum pump according to claim 8, wherein the vacuum pump is formed as described above. The first Holbeck thread (140) and the second Holbeck thread (142) provide a higher suction capacity for the second Holbeck thread (142) relative to the first Holbeck thread (140). The vacuum pump according to claim 8 or 9, wherein the vacuum pump is formed as described above. Each holbek thread (140, 142) performs each pumping action on the side of the stator element (126, 126 ′, 126 ″) or in cooperation with the stator element (126, 126 ′, 126 ″). A plurality of webs (130, 130 ') that are formed on the side surface of the rotor element (128) of the portion and that are thread-shaped and that move on the side surface, and a plurality of grooves (132, 132) that are positioned therebetween The vacuum pump according to any one of claims 8 to 10, wherein the vacuum pump is formed by '). The higher compression capacity of the first Holbeck thread (140) and / or the higher suction capacity of the second Holbeck thread (142), both the Holbeck threads (140, 142) have the following parameters: That is:
The number of grooves (132, 132 ′), the inclination angle of the grooves (132, 132 ′) or the web (130, 130 ′), the stator elements (126, 126 ′, 126 ″) and the associated rotor elements (128). ), The depth of the groove (132, 132 '), the height of the web (130, 130'), the width of the groove (132, 132 '), the width of the web (130, 130') width,
The vacuum pump according to claim 8, wherein the vacuum pump is achieved by being different in at least one of the following. A vacuum device, in particular a leak locator, or a mass spectrometer, comprising a vacuum pump according to any one of claims 1 to 12, integrated in the vacuum device or provided in the vacuum device. Features vacuum equipment.

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