Turbomolecular pump

Abstract

A pump, in particular a turbomolecular pump, comprises a stator with at least one stator element and a rotor with at least one rotor element, which can be driven by a motor to rotate about an axis of rotation, together forming a pump stage arranged in a pump housing, wherein the axis of rotation defines an axial direction and the pump housing defines a pump inlet and at least one pump outlet, wherein the at least one pump outlet is laterally offset in the axial direction with respect to the axis of rotation, wherein the pump inlet has at least one inlet opening, in particular exactly one inlet opening, which defines an inlet plane and the at least one pump outlet has at least one outlet opening, in particular exactly one outlet opening, which defines an outlet plane.wherein the inlet plane and the outlet plane are the same plane or parallel planes, or wherein the inlet plane and the outlet plane enclose an angle of greater than 90° to less than 180°.

Description

[0001] The invention relates to a turbomolecular pump.

[0002] Many types of pumps, especially turbomolecular pumps, comprise a stator and a rotor driven by an electric motor to rotate around an axis of rotation, both housed within a pump casing. The casing defines one or more inlets and one or more outlets.

[0003] Pumps are used to move a fluid from the pump inlet to the pump outlet, creating a fluid flow through the pump housing. The fluid can be a gas or a liquid. They are used, for example, to create a vacuum in a receiver connected to the inlet. However, applications are also conceivable where the pump's inlet pressure is virtually the same as its outlet pressure. This allows the fluid to be conveyed through a component fluidically connected to the inlet and / or outlet, which is provided by the customer.

[0004] The customer-side component could be, for example, a chamber of a measuring device or similar. The pressure prevailing at the inlet and / or outlet during pump operation could, for example, lie in a range between the upper end of a rough vacuum and the middle end of a fine vacuum.

[0005] Depending on the customer application, a pump must meet various requirements. For example, in many cases it is desirable for the pump to be as compact and cost-effective as possible. At the same time, however, the pump should also be powerful and durable.

[0006] Furthermore, the pump's inlet and outlet should generally be as easily accessible as possible, so that the pump can be connected to components of a customer's setup in a straightforward manner.

[0007] German patent DE 601 01 898 T2 discloses a turbomolecular pump according to claim 1 with the difference that the pump does not have exactly one pump inlet, but two pump inlets.

[0008] The publications EP 4 108 932 A1, DE 10 2007 027352 A1, EP 3 032 106 A1, US 6 106 223 A, DE 20 2013 009655 U1, DE 198 21 634 A1, DE 94 17 422 U1, DE 88 08 870 U1 , DE 10 2010 032346 A1, EP 3 296 571 A1 and US 2015 / 167679 A1 disclose related pumps.

[0009] It is therefore an object of the invention to provide a more economical, compact and versatile turbomolecular pump.

[0010] This problem is solved according to the invention by the features of claim 1.

[0011] In particular, the problem is solved by a turbomolecular pump comprising a stator with at least one stator element and a rotor with at least one rotor element, which can be driven by a motor to rotate about an axis of rotation. Together, these form a pump stage arranged in a pump housing. The axis of rotation defines an axial direction, and the pump housing defines exactly one pump inlet and exactly one pump outlet.

[0012] The pump outlet is laterally offset in the axial direction with respect to the axis of rotation. According to one embodiment, the centers of the inlet and outlet can be positioned side by side rather than one above the other in the axial direction, which simplifies the integration of the pump into some structures.

[0013] The pump inlet has exactly one inlet opening that defines an inlet plane, and the pump outlet has exactly one outlet opening that defines an outlet plane.

[0014] The inlet plane and the outlet plane lie in the same plane. In other words, the inlet opening and the outlet opening have the same orientation.

[0015] The design described above allows for particularly simple and space-saving connection of a customer-supplied component to the turbomolecular pump. It sometimes happens that a component needs to be connected to the same side of the turbomolecular pump as its inlet. If a conventional pump is used in such a "corner" application, where the pump inlet and outlet are located on opposite sides, the customer must first install a corresponding "diversion" to reverse the fluid flow direction in order to connect the component. This can be complex and costly and requires additional installation space. With the turbomolecular pump according to the invention, in which the inlet and outlet are located on the same side of the pump and laterally offset from each other, such a "diversion" is unnecessary.

[0016] Further embodiments are specified in the dependent claims, the description and the accompanying drawings.

[0017] The inlet plane and the outlet plane can be perpendicular to the axial direction. However, the inlet plane and the outlet plane can also be oblique to the axial direction.

[0018] According to one embodiment, the pump outlet, viewed from the side of the pump with respect to the inflow direction of a fluid flow, can be located above or in the region of an inlet-side first pumping stage. In particular, the turbomolecular pump has exactly one pumping stage.

[0019] The turbomolecular pump can be operated or run in a pressure range between 0.01 mbar (1 Pa) and 100 mbar (10⁴ < Pa), in particular between 1 mbar (10² < Pa) and 10 mbar (10³ < Pa). However, in certain applications, the pressures prevailing during the operation of the turbomolecular pump can also be above 100 mbar (10⁴ < Pa) or below 1 mbar (1 Pa).

[0020] The rotor can comprise fewer than five rotor elements, in particular rotor disks. Additionally or alternatively, the stator can comprise fewer than five stator elements, in particular stator disks. It has proven particularly advantageous if the rotor has fewer than five, preferably three, rotor elements and the stator has fewer than five, preferably three, stator elements. However, other configurations can be chosen for specific applications.

[0021] Furthermore, the turbomolecular pump can be cooled exclusively by air. Specifically, the pump housing can incorporate cooling elements, such as cooling fins and / or cooling pins, extending away from the pump housing. Additionally or alternatively, the turbomolecular pump can also feature active cooling, which may include a fan that generates an airflow across the housing and / or, if present, the cooling elements. However, active cooling can also be liquid-based. For example, the turbomolecular pump can have one or more cooling lines and / or channels located around and / or within the pump housing, through which the cooling fluid, such as water, flows.

[0022] The turbomolecular pump can be a single-flow pump, meaning that the turbomolecular pump does not have any functionally parallel pumping stages.

[0023] The turbomolecular pump can also include at least one side channel, at least one Holweck stage and / or at least one Siegbahn stage.

[0024] The pump inlet has an inlet area and the pump outlet has an outlet area, wherein the outlet area is greater than or equal to 100% of the inlet area. In particular, the outlet area is greater than or equal to 150%, greater than or equal to 200%, greater than or equal to 250%, or greater than or equal to 300% of the inlet area. In particular, the ratio of inlet area to outlet area can be 1:1, 1:1.5, 1:2, 1:2.5, 1:3, or less.

[0025] Alternatively, the inlet area and the outlet area are approximately the same size. "Approximately the same size" includes differences in the area sizes of up to 20%, preferably up to 10%, and particularly preferably up to 5%.

[0026] For a particularly space-saving design, the pump outlet can be configured as a slot with at least one curved side. In particular, the shape of the curved side can mimic the shape of the inlet opening. Preferably, the slot is configured, at least partially, as a circular segment, with the two shorter transverse sides of the slot running parallel to each other and the two longitudinal sides of the slot having the same curvature and also running parallel to each other.

[0027] For a particularly robust design, the pump housing can be manufactured as a single piece. In particular, the pump inlet and outlet can be integrated into a common flange section of the turbomolecular pump, which significantly simplifies connection.

[0028] However, the pump inlet and pump outlet can also be formed on separate housing parts of the pump housing, for example on separate flange sections, which makes the turbomolecular pump more versatile.

[0029] The invention is described below by way of example with reference to advantageous embodiments and the accompanying figures. These show, schematically: Fig. 1 a perspective view of a turbomolecular pump not according to the invention, Fig. 2 a view of the underside of the turbomolecular pump of Fig. 1 , Fig. 3 a cross-section of the turbomolecular pump along the in Fig. 2 Section line AA shown, Fig. 4 a cross-sectional view of the turbomolecular pump along the in Fig. 2 Section line BB, Fig. 5 shows a cross-sectional view of the turbomolecular pump along the line shown in Fig. 2The section line CC shown, Fig. 6 a cross-sectional view of a turbomolecular pump according to an embodiment of the invention according to the invention, Figs. 7-10 cross-sectional views of turbomolecular pumps according to embodiments of the invention that are not according to the invention.

[0030] The in Fig. 1 The turbomolecular pump 111 shown, which is not according to the invention, comprises a pump inlet 115 surrounded by an inlet flange 113, to which a receiver (not shown) can be connected in a manner known per se. The gas from the receiver can be drawn out of the receiver via the pump inlet 115 and conveyed through the pump to a pump outlet 117, to which a backing pump, such as a rotary vane pump, can be connected.

[0031] The inlet flange 113 forms a Fig. 1The upper end of the housing 119 of the vacuum pump 111. The housing 119 comprises a lower part 121, to which an electronics housing 123 is attached laterally. The electronics housing 123 contains electrical and / or electronic components of the vacuum pump 111, e.g., for operating an electric motor 125 located in the vacuum pump (see also Fig. 3 The electronics housing 123 has several connections 127 for accessories. In addition, a data interface 129, e.g. according to the RS485 standard, and a power supply connection 131 are located on the electronics housing 123.

[0032] There are also turbomolecular pumps that do not have such an attached electronics housing, but are connected to external drive electronics.

[0033] The housing 119 of the turbomolecular pump 111 has a flood inlet 133, in particular in the form of a flood valve, through which the vacuum pump 111 can be flooded. In the area of ​​the lower part 121, a purge gas connection 135, also referred to as a purge gas connection, is also arranged, through which purge gas can be supplied to protect the electric motor 125 (see e.g. Fig. 3 The gas pumped by the pump can be introduced into the motor compartment 137, in which the electric motor 125 is housed in the vacuum pump 111. Two coolant connections 139 are also arranged in the lower part 121, one of which serves as an inlet and the other as an outlet for coolant that can be directed into the vacuum pump for cooling purposes. Other existing turbomolecular vacuum pumps (not shown) are operated exclusively with air cooling.

[0034] The lower side 141 of the vacuum pump can serve as a base, allowing the vacuum pump 111 to be operated standing upright on its underside 141. Alternatively, the vacuum pump 111 can be attached to a receiver via the inlet flange 113 and thus operated in a suspended position. Furthermore, the vacuum pump 111 can be designed to operate even when oriented differently than described. Fig. 1 As shown. It is also possible to implement embodiments of the vacuum pump in which the underside 141 can be arranged facing sideways or upwards instead of downwards. In principle, any angle is possible.

[0035] Other existing turbomolecular vacuum pumps (not shown), which are particularly larger than the pump shown here, cannot be operated in a standing position.

[0036] On the underside 141, which is in Fig. 2As shown, various screws 143 are arranged, by means of which components of the vacuum pump, not further specified here, are fastened to one another. For example, a bearing cover 145 is attached to the underside 141.

[0037] Mounting holes 147 are also arranged on the underside 141, via which the pump 111 can be attached to a support surface, for example. This is not possible with other existing turbomolecular vacuum pumps (not shown), which are particularly larger than the pump shown here.

[0038] In the Figures 2 to 5 A coolant line 148 is shown, in which the coolant introduced and removed via the coolant connections 139 can circulate.

[0039] Like the sectional views of the Figures 3 to 5 As shown, the vacuum pump comprises several process gas pumping stages for conveying the process gas present at the pump inlet 115 to the pump outlet 117.

[0040] A rotor 149 is arranged in the housing 119, which has a rotor shaft 153 rotatable about a rotation axis 151.

[0041] The turbomolecular pump 111 comprises several turbomolecular pump stages connected in series to provide pumping action. These stages have several radial rotor disks 155 attached to the rotor shaft 153 and stator disks 157 arranged between the rotor disks 155 and fixed in the housing 119. Each rotor disk 155 and an adjacent stator disk 157 form a turbomolecular pump stage. The stator disks 157 are held at a desired axial distance from each other by spacer rings 159.

[0042] The vacuum pump also includes Holweck pump stages arranged radially within one another and connected in series to effectively pump the pump. Other turbomolecular vacuum pumps exist (not shown) that do not have Holweck pump stages.

[0043] The rotor of the Holweck pump stages comprises a rotor hub 161 arranged on the rotor shaft 153 and two cylindrical Holweck rotor sleeves 163, 165 attached to and supported by the rotor hub 161, which are oriented coaxially to the axis of rotation 151 and nested one inside the other in the radial direction. Furthermore, two cylindrical Holweck stator sleeves 167, 169 are provided, which are also oriented coaxially to the axis of rotation 151 and nested one inside the other in the radial direction.

[0044] The pump-active surfaces of the Holweck pump stages are formed by the outer surfaces, i.e., the radial inner and / or outer surfaces, of the Holweck rotor sleeves 163, 165 and the Holweck stator sleeves 167, 169. The radial inner surface of the outer Holweck stator sleeve 167 faces the radial outer surface of the outer Holweck rotor sleeve 163, forming a radial Holweck gap 171, and together they form the first Holweck pump stage following the turbomolecular pumps. The radial inner surface of the outer Holweck rotor sleeve 163 faces the radial outer surface of the inner Holweck stator sleeve 169, forming a radial Holweck gap 173, and together they form a second Holweck pump stage. The radial inner surface of the inner Holweck stator sleeve 169 lies opposite the radial outer surface of the inner Holweck rotor sleeve 165, forming a radial Holweck gap 175, and together they form the third Holweck pumping stage.

[0045] At the lower end of the Holweck rotor sleeve 163, a radially extending channel can be provided, through which the radially outer Holweck slot 171 is connected to the central Holweck slot 173. Furthermore, a radially extending channel can be provided at the upper end of the inner Holweck stator sleeve 169, through which the central Holweck slot 173 is connected to the radially inner Holweck slot 175. This connects the nested Holweck pump stages in series. A connecting channel 179 to the outlet 117 can also be provided at the lower end of the radially inner Holweck rotor sleeve 165.

[0046] The aforementioned pump-active surfaces of the Holweck stator sleeves 167, 169 each have several Holweck grooves spiraling around the axis of rotation 151 in the axial direction, while the opposite outer surfaces of the Holweck rotor sleeves 163, 165 are smooth and drive the gas forward in the Holweck grooves for the operation of the vacuum pump 111.

[0047] For the rotatable mounting of the rotor shaft 153, a rolling bearing 181 is provided in the area of ​​the pump outlet 117 and a permanent magnet bearing 183 is provided in the area of ​​the pump inlet 115.

[0048] In the area of ​​the rolling bearing 181, a conical injection nut 185 with an outer diameter increasing towards the rolling bearing 181 is provided on the rotor shaft 153. The injection nut 185 is in sliding contact with at least one wiper of a fluid reservoir. In other existing turbomolecular vacuum pumps (not shown), an injection screw may be provided instead of an injection nut. Since different designs are thus possible, the term "injection tip" is also used in this context.

[0049] The operating fluid reservoir comprises several stacked absorbent discs 187, which are impregnated with an operating fluid for the rolling bearing 181, e.g. with a lubricant.

[0050] During operation of the vacuum pump 111, the operating fluid is transferred by capillary action from the fluid reservoir via the wiper to the rotating injection nut 185 and, as a result of centrifugal force, is conveyed along the injection nut 185 in the direction of the increasing outer diameter of the injection nut 185 towards the rolling bearing 181, where it performs, for example, a lubricating function. The rolling bearing 181 and the fluid reservoir are enclosed in the vacuum pump by a trough-shaped insert 189 and the bearing cover 145.

[0051] The permanent magnet bearing 183 comprises a rotor-side bearing half 191 and a stator-side bearing half 193, each containing a ring stack of several axially stacked permanent magnet rings 195, 197. The ring magnets 195, 197 face each other, forming a radial bearing gap 199, with the rotor-side ring magnets 195 arranged radially outside and the stator-side ring magnets 197 radially inside. The magnetic field present in the bearing gap 199 induces magnetic repulsion forces between the ring magnets 195, 197, which result in the radial support of the rotor shaft 153. The rotor-side ring magnets 195 are supported by a support section 201 of the rotor shaft 153, which radially surrounds the ring magnets 195 on the outside.The stator-side ring magnets 197 are supported by a stator-side support section 203, which extends through the ring magnets 197 and is suspended from radial struts 205 of the housing 119. Parallel to the axis of rotation 151, the rotor-side ring magnets 195 are fixed by a cover element 207 coupled to the support section 201. The stator-side ring magnets 197 are fixed parallel to the axis of rotation 151 in one direction by a retaining ring 209 connected to the support section 203 and a retaining ring 211 also connected to the support section 203. A disc spring 213 may also be provided between the retaining ring 211 and the ring magnets 197.

[0052] Within the magnetic bearing, an emergency or catch bearing 215 is provided, which runs freely without contact during normal operation of the vacuum pump 111 and only engages when there is excessive radial deflection of the rotor 149 relative to the stator, in order to form a radial stop for the rotor 149 and thus prevent a collision between the rotor-side and stator-side structures. The catch bearing 215 is designed as an unlubricated rolling bearing and forms a radial gap with the rotor 149 and / or the stator, which causes the catch bearing 215 to be disengaged during normal pump operation. The radial deflection at which the catch bearing 215 engages is dimensioned to be large enough so that the catch bearing 215 does not engage during normal operation of the vacuum pump, and simultaneously small enough to prevent a collision between the rotor-side and stator-side structures under all circumstances.

[0053] The vacuum pump 111 comprises the electric motor 125 for rotating the rotor 149. The armature of the electric motor 125 is formed by the rotor 149, whose rotor shaft 153 extends through the motor stator 217. A permanent magnet arrangement can be arranged radially on the outside or embedded in the section of the rotor shaft 153 extending through the motor stator 217. A space 219 is arranged between the motor stator 217 and the section of the rotor 149 extending through the motor stator 217. This space comprises a radial motor gap through which the motor stator 217 and the permanent magnet arrangement can magnetically influence each other to transmit the drive torque.

[0054] The motor stator 217 is fixed in the housing within the motor compartment 137 provided for the electric motor 125. A purge gas, also known as a sealing gas, which can be, for example, air or nitrogen, can enter the motor compartment 137 via the purge gas connection 135. This purge gas protects the electric motor 125 from process gas, e.g., from corrosive components of the process gas. The motor compartment 137 can also be evacuated via the pump outlet 117, meaning that the vacuum pressure in the motor compartment 137 is at least approximately equal to that produced by the backing pump connected to the pump outlet 117.

[0055] Between the rotor hub 161 and a wall 221 bounding the engine compartment 137, a so-called labyrinth seal 223, which is known per se, can also be provided, in particular to achieve a better seal of the engine compartment 217 against the radially outside Holweck pump stages.

[0056] The Fig. 6 Figure 1 shows an exemplary embodiment of a pump 10 according to the invention. The pump 10 is a turbomolecular pump and comprises a pump housing 14 in which a stator and a rotor 149 are arranged, together forming a pump stage 26. The rotor 149 can be driven to rotate about a rotation axis 151 by means of an (electric) motor 125, the rotation axis 151 defining an axial direction.

[0057] The pump housing 14 has exactly one pump inlet 115 and exactly one pump outlet 117. The pump inlet 115 is arranged coaxially with respect to the axial direction. However, the pump inlet 115 can also be arranged laterally offset in the axial direction, i.e., next to the axis of rotation 151. The pump outlet 117 is located laterally offset in the axial direction next to the pump inlet 115, the pump stage 26, and the axis of rotation 151. Furthermore, the pump outlet 117 is located above the pump stage 26 with respect to an inflow direction 24 of a fluid flow 22.

[0058] The pump inlet 115 has exactly one inlet opening 14, and the pump outlet 117 has exactly one outlet opening 16. The inlet opening 14 has an inlet area 28 and defines an inlet plane 18. The outlet opening 16 has an outlet area 30 and defines an outlet plane 20. In the embodiment shown, the inlet area 28 and the outlet area 30 are essentially the same size. However, it is also possible for the outlet area 30 to be larger than the inlet area 28.

[0059] The pump housing 14 comprises a base body 44 and an outlet section 46. In the embodiment shown, the base body 44 and the outlet section 46 are formed in one piece, i.e., they form the pump housing 14 of the pump 10. The pump inlet 115 and the pump outlet 117 are accordingly formed in a common housing 14 of the pump 14, in particular they are formed in a common flange section 36 of the pump 10 (see Figure 1). Fig. 10 , however, the size of the inlet and outlet areas shown is not according to the invention).

[0060] However, a configuration is also possible in which the base body 44 and the outlet section 46 are separate housing sections of the pump 10. In such an embodiment, the pump inlet 115 and the pump outlet 117 are formed in separate housing sections of the pump 10, namely in two different flange sections that connect to the base body 44 and / or the outlet section 46 of the pump housing 14. The described configuration of the pump housing 14 also applies to the embodiments described below.

[0061] The inlet plane 18 and the outlet plane 20 are at the same level in the axial direction, meaning they lie in or form the same plane 18, 20. Furthermore, the inlet plane 18 and the outlet plane 20 are perpendicular to the axial direction. The inlet opening 14 and the outlet opening 16 have the same orientation, meaning they point in the same direction. Therefore, the inlet opening 14 and the outlet opening 16 are accessible from the same side of the pump 10.

[0062] During operation of pump 10, a fluid flow 22 is generated which, upon entering the inlet opening 14 and flowing through the pump stage 26, has an inflow direction 24 and upon exiting the outlet opening 16, has an outflow direction 38. The inflow direction 24 and the outflow direction 38 are opposite (or antiparallel to each other) and parallel to the axial direction, meaning that the fluid flow 22 undergoes a reversal of direction of approximately 180° from the inlet to the outlet of pump 10.

[0063] A bottom surface 48 of the base body 44 of the pump housing 14 is axially offset from a bottom surface 50 of the outlet section 46 of the pump housing 14. However, a configuration is also possible in which the two bottom surfaces 48 and 50 are aligned.

[0064] Furthermore, the pump 10 features passive cooling. The passive cooling can be integrated directly into the pump housing 14. Alternatively, the passive cooling and the pump housing 14 can also be designed as separate components. For example, the passive cooling can be attached to the pump housing 14. In the embodiment shown, the passive cooling comprises a plurality of cooling fins 52 extending away from the pump housing 14. Additionally or alternatively, the passive cooling can also comprise a plurality of cooling pins (not shown). Additionally or alternatively, the pump 10 can also feature active cooling, e.g., a cooling fan and / or liquid cooling, in particular water cooling.

[0065] The one in Fig. 7 The pump 10 shown, which is not according to the invention, differs from the one shown in the Fig. 6The pump 10 shown differs essentially in that the inlet plane 18 and the outlet plane 20 are not in the same plane but are parallel planes. That is, the inlet plane 18 is axially offset from the outlet plane 20.

[0066] In the illustrated embodiment, the inlet plane 18, viewed in the inflow direction 24, lies above or in front of the outlet plane 20. However, a configuration is also possible in which the inlet plane 18 lies below the outlet plane 20.

[0067] The one in Fig. 8A The pump 10 shown, which is not according to the invention, differs from those shown in the Fig. 6 and 7The pumps 10 shown are distinguished essentially by the fact that the inlet opening 14 and the outlet opening 16 do not have the same orientation, that is, the surface normals of the openings 14 and 16 do not point in the same direction. In particular, the inlet plane 18 and the outlet plane 20 enclose an angle 40 of greater than 90° to less than 180°. In the embodiment shown, the angle 40 is approximately 150°. However, the angle 40 can also be greater or less than 150°. As shown in the Fig. 8B As shown in more detail, the angle 40 between the inlet plane 18 and the outlet plane 20 is to be understood as the opposite angle which is greater than 90°.

[0068] The fluid flow 22 generated during the operation of pump 10 has an outflow direction 38 that is not opposite to the inflow direction 24, and the fluid flow 22 undergoes a change in direction of more than 90° and less than 180° in total.

[0069] The inlet plane 18 is perpendicular to the axial direction, and the outlet plane 20 is not perpendicular, i.e., it is inclined to the axial direction. However, it is also possible to configure the outlet plane 20 as perpendicular to the axial direction, while the inlet plane 18 is not. Furthermore, both planes 18 and 20 can also be arranged inclined to the axial direction.

[0070] In a side view of the pump 10, the outlet opening 16 is located at least partially, and in particular completely, below the inlet opening 14 with respect to the inflow direction 24. However, it is also conceivable that the outlet opening 16 is located at least partially, and in particular completely, above the inlet opening 14.

[0071] The one in Fig. 9 The pump 10 shown, which is not according to the invention, differs from those shown in the Figs. 6 to 8The pumps 10 shown are essentially distinguished by the fact that the pump outlet 117 has two outlet openings 16a and 16b.

[0072] The outlet openings 16a, 16b each have an outlet area that is smaller than the inlet area 28. In the embodiment shown, the ratio of inlet area 28 to outlet area is, for example, approximately 5:1. It is understood, however, that the ratio can also assume any value, in particular between 1:1 and 10:1 or between 1:1 and 1:10, in particular between 1:1 and 5:1 or between 1:1 and 1:5, in particular between 1:1 and 3:1 or between 1:1 and 1:3.

[0073] The outlet opening 16a defines a first outlet plane 20a, which lies in the same plane as the inlet plane 18. The outlet opening 16b defines a second outlet plane 20b, which is parallel to the first outlet plane 20a and the inlet plane 18. All planes 18, 20a, and 20b are perpendicular to the axial direction, so that the normals of the inlet opening 14 and the first outlet opening 16a have the same orientation with respect to the axial direction, and the normal of the second outlet opening 16b points in the opposite direction. In particular, the inlet opening 14 and the first outlet opening 16a are easily accessible from the inlet side of the pump 10, and the second outlet opening 16b is easily accessible from the side of the pump 10 opposite the inlet opening 14.

[0074] However, a configuration is also possible in which the inlet plane 14, the first outlet plane 20a and / or the second outlet plane 20b are not perpendicular, i.e., oblique to the axial direction.

[0075] The fluid flow 22 generated during the operation of pump 10 has an inflow direction 24 and a first and a second outflow direction 38a, 38b, each running parallel to the axial direction. The inflow direction 24 and the first outflow direction 38a are antiparallel, and the inflow direction 24 and the second outflow direction 38b are parallel to each other. The fluid therefore exits both on the inlet side and on the side of pump 10 opposite the inlet 115; that is, the fluid flow splits at the pump outlet 117.

[0076] The first outlet opening 16a and the inlet opening 14 are at the same height with respect to the axial direction. However, it is also conceivable that the first outlet opening 16a and the inlet opening 14 are axially offset from each other.

[0077] The first outlet opening 16a and the second outlet opening 16b are arranged coaxially, i.e., their centers are aligned axially. However, it is also possible for the first outlet opening 16a and the second outlet opening 16b to be laterally offset from each other axially. The openings 16a and 16b can be identical in shape and size or differ.

[0078] In the embodiment shown, the pump outlet 117 has two opposing outlet openings 16a, 16b. However, the pump outlet 117 can also have more than two, for example three, four, five or more outlet openings 16, each defining the same or parallel outlet planes 20, or defining outlet planes 20 that enclose an angle 40 of greater than 90° to less than 180°.

[0079] The Fig. 10 Figure 1 shows a top view of a pump 10 not according to the invention, with a flange section 36 in which both the inlet opening 14 and the outlet opening 16 are formed. The flange section 36 is formed integrally with the pump housing 14. However, the flange section 36 can also be formed as a separate housing component of the pump housing 14, i.e., the pump housing 14 can be formed in two or more parts.

[0080] The inlet opening 14 is circular and is located centrally above the axis of rotation 151. The outlet opening 16 is laterally offset from the inlet opening 14 and is designed as a slot 32 with two parallel curved sides 34 and two parallel straight sides 42. The curvature of the longitudinal sides 34 mirrors the circular shape of the inlet 117, which makes the pump 10 particularly compact. In the illustrated embodiment, the ratio of inlet area 28 to outlet area 30 is approximately 3:1. However, this ratio can be adjusted as required.

[0081] The shape of the inlet opening 14 is not limited to a circular shape. It can, for example, also have the shape of a rectangle, particularly a square, or an ellipse. Similarly, the shape of the outlet opening 16 is not limited to a slot shape with two parallel curved sides 34 and two parallel straight sides 42. Preferably, but not necessarily, the shape of the outlet opening 16 is designed to be complementary to the shape of the inlet opening 14. The above-described configurations of the inlet and outlet openings can, in principle, also be applied to other embodiments.

[0082] It is understood that the ratio of inlet to outlet area 28, 30, the number of outlet openings 16, the orientation of the openings 14, 16 or of the inlet and outlet planes 18, 20 with respect to the axial direction, the relative position of the openings 14, 16 to each other and with respect to the pump stage, the relative position of the undersides 44, 46 to each other, as well as the single-piece or multi-piece design of the pump housing 14 can be combined as desired according to the various described embodiments. However, a pump is only a pump according to the invention if it is a turbomolecular pump according to claim 1. Reference symbol list

[0083] 111 Turbomolecular pump 113 Inlet flange 115 Pump inlet 117 Pump outlet 119 Housing 121 Bottom section 123 Electronics housing 125 Electric motor 127 Accessory connection 129 Data interface 131 Power supply connection 133 Flood inlet 135 Sealing gas connection 137 Motor compartment 139 Coolant connection 141 Bottom side 143 Screw 145 Bearing cover 147 Mounting hole 148 Coolant line 149 Rotor 151 Rotation shaft 153 Rotor shaft 155 Rotor disc 157 Stator disc 159 Spacer ring 161 Rotor hub 163 Holweck rotor sleeve 165 Holweck rotor sleeve 167 Holweck stator sleeve 169 Holweck stator sleeve 171 Holweck gap 173 Holweck gap 175 Holweck gap 179 Connecting channel 181 Rolling bearing 183 Permanent magnet bearing 185 Injection nut 187 Washer 189 Insert 191 Rotor-side bearing half 193 Stator-side bearing half 195 Ring magnet 197 Ring magnet 199 Bearing gap 201 Support section 203 Support section 205 Radial strut 207 Cover element 209 Support ring 211 Mounting ring 213 Disc spring 215 Emergency or217 Catching bearing 219 Motor stator 219 Intermediate space 221 Wall 223 Labyrinth seal 10 Pump 12 Rotor element 14 Inlet opening 16 Outlet opening 18 Inlet plane 20 Outlet plane 22 Fluid flow 24 Inflow direction 26 Pump stage 28 Inlet area 30 Outlet area 32 Slot 34 Curved sides of the slot 36 Flange section 38 Outflow direction 40 Angle between inlet plane and outlet plane 42 Straight sides of the slot 44 Base body 46 Outlet section 48 Underside of the base body 50 Underside of the outlet section 52 Cooling fins.

Claims

1. A turbomolecular pump (111) comprising a stator, which has at least one stator element, and a rotor (149) which can be driven by a motor (125) to rotate about an axis of rotation (151) and which has at least one rotor element (12), said stator and rotor together forming a pump stage (26) which is arranged in a pump housing (14), wherein the axis of rotation (151) defines an axial direction and the pump housing (14) defines exactly one pump inlet (115) and exactly one pump outlet (117), wherein the pump outlet (117) is formed laterally offset with respect to the axis of rotation (151), viewed in the axial direction, wherein the pump inlet (115) has exactly one inlet opening (14), which defines an inlet plane (18), and the pump outlet (117) has exactly one outlet opening (16) which defines an outlet plane (20), wherein the inlet plane (18) and the outlet plane (20) are the same plane, wherein the pump inlet (115) has an inlet area (28) and the pump outlet (117) has an outlet area (30), and wherein the outlet area (30) is greater than or equal to 100% of the inlet area (28) or wherein the sizes of the outlet area (30) and the inlet area (28) differ from one another by up to 20%.

2. A turbomolecular pump (111) according to the preceding claim, wherein the inlet plane (18) and the outlet plane (20) are perpendicular to the axial direction.

3. A turbomolecular pump (111) according to claim 1 or 2, wherein the pump outlet (117), viewed in a side view of the turbomolecular pump (111), is arranged above a first pump stage (26) at the inlet side with respect to an inflow direction (24) of a fluid flow (22).

4. A turbomolecular pump (111) according to at least one of the preceding claims, wherein the turbomolecular pump (111) can be operated in a pressure range between 0.01 mbar and 100 mbar, in particular between 1 mbar and 10 mbar.

5. A turbomolecular pump (111) according to at least one of the preceding claims, wherein the rotor (149) comprises fewer than five rotor elements (12), in particular rotor disks (155), and / or wherein the stator comprises fewer than five stator elements, in particular stator disks (157).

6. A turbomolecular pump (111) according to at least one of the preceding claims, wherein the turbomolecular pump (111) exclusively has an air cooling, in particular wherein the pump housing (14) has a plurality of cooling elements, in particular cooling fins (50) and / or cooling pins, which extend away from the pump housing (14), and / or wherein the turbomolecular pump (111) has an active cooling.

7. A turbomolecular pump (111) according to at least one of the preceding claims, wherein the turbomolecular pump (111) is a single-flow pump.

8. A turbomolecular pump (111) according to at least one of the preceding claims, wherein the turbomolecular pump (111) comprises at least one side channel, at least one Holweck stage and / or at least one Siegbahn stage.

9. A turbomolecular pump (111) according to at least one of the preceding claims, wherein the outlet area (30) is greater than or equal to 200%, greater than or equal to 300%, greater than or equal to 400% or greater than or equal to 500% of the inlet area (28).

10. A turbomolecular pump (111) according to at least one of the preceding claims, wherein the pump outlet (117) is formed as a slot (32) having at least one curved side (34), in particular wherein a shape of the curved side (34) is modeled on the shape of the inlet opening (14).

11. A turbomolecular pump (111) according to at least one of the preceding claims, wherein the pump housing (14) is formed in one piece, in particular wherein the pump inlet (115) and the pump outlet (117) are formed in a common flange section (36) of the turbomolecular pump (111).

12. A turbomolecular pump (111) according to at least one of the claims 1 to 10, wherein the pump inlet (115) and the pump outlet (117) are formed at separate housing parts of the pump housing (14).

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