Vacuum device and method for operating same

Abstract

A vacuum device comprises a wear detection device and a protective device. The wear detection device is configured to detect a set of operating parameters of the vacuum device and, based on these parameters, to determine at least one wear indicator for the vacuum device, indicating the wear of at least one component of the vacuum device. The protective device is configured to execute a measure to reduce the wear of the vacuum device when the at least one wear indicator reaches a predetermined state.

Description

[0001] The invention relates to a vacuum pump and a method for operating such a vacuum pump.

[0002] Most vacuum pumps have moving parts that are subject to wear. Gauge tubes used in vacuum systems also have parts that are subject to wear due to heavy physical stress. The wear of such vacuum devices depends on the operating and environmental conditions of the particular vacuum device, as well as on the aging of the stressed components of the vacuum device.

[0003] Wear and tear to components of a vacuum device can result in certain functions of the vacuum device not being performed at all or no longer being performed to the required extent. For example, a turbomolecular vacuum pump may have rolling element bearings and / or backup bearings for its rotor, where a certain amount of wear can ultimately lead to failure of the vacuum pump. Furthermore, wear and tear can lead to pre-damage to certain components of the vacuum device, which can be exacerbated by continued uncontrolled operation of the vacuum device and can lead to complete failure of the vacuum device. This can occur, for example, if a vacuum pump continues to be operated at rated conditions in terms of temperature, power, and speed despite some pre-damage to a bearing. If, for example, pre-damage to the bearing goes undetected, operation at rated conditions shortens the time until the pump fails.

[0004] To prevent the failure of a vacuum device due to wear and tear, maintenance recommendations or similar specifications are often provided, for example, specifying a check of the vacuum device after a specified operating period or under certain other conditions. However, a vacuum device failure can occur before the end of such a maintenance period, for example, due to the operating mode of a particular vacuum pump if wear and tear on certain components of the vacuum device is not detected. Conversely, the planned operating time until maintenance can be set too conservatively, resulting in unnecessarily early maintenance. This leads to unnecessary costs for the operation of the vacuum device.

[0005] EP 3 832 141 A1 describes a vacuum pump and a method for operating the same. The vacuum pump has a rotor in which a specific disturbance event is detected, affecting the rotor and a backup bearing for the rotor. During the disturbance event, a wear increment is estimated, which is added to a variable for the total wear of the backup bearing. Based on this total wear variable, a decision is made as to whether a measure to stabilize the rotor is taken.

[0006] US 2019 / 0383300 A1 describes a vacuum pump with a rolling bearing to which a lubricant is supplied by a special pump. Vibrations and the temperature of the vacuum pump are measured to control the lubricant supply.

[0007] EP 3 456 979 A1 describes a vacuum pump for which a wear reserve is determined in percent until a recommended maintenance is due. For this purpose, various operating parameters of the vacuum pump are recorded over a specific period of time.

[0008] DE 101 57 143 A1 describes a device and method for detecting wear in pumps. Wear-relevant operating parameters of the pumps are recorded using sensors. Using an evaluation device, the recorded operating parameters are used to determine an expected value for the operating period until the next maintenance or replacement of certain pump parts.

[0009] An object of the invention is to provide a vacuum pump and a method for operating such a pump in which a failure of the vacuum pump due to wear is avoided or at least delayed.

[0010] This object is achieved by a vacuum pump and a method having the features of the independent claims. Advantageous developments of the invention are specified in the subclaims, the description, and the drawings.

[0011] The vacuum pump comprises a wear detection device and a protection device. The wear detection device is designed to detect a set of operating variables of the vacuum pump and, for each of the detected operating variables, to determine a respective wear indicator for the vacuum pump, which indicates the wear of at least one component of the vacuum pump. The at least one component can, in particular, be a rolling bearing of the vacuum pump. The protection device is designed to carry out a measure for reducing the wear of the vacuum pump when at least one of the wear indicators assumes a predetermined state, i.e., exceeds a respective predetermined threshold value.

[0012] The set of operating variables of the vacuum pump includes, among other things, the number of operating hours of the vacuum pump. In this case, the wear detection device can be designed to record the previous operating hours of the vacuum pump. The wear detection device can additionally or alternatively be designed to detect specific, predetermined fault events and assign a detected fault event to a specific wear. Based on the total number of operating hours and optionally also based on the detected fault events of the vacuum pump, the wear detection device can assign a specific numerical value to these detected operating variables as a wear indicator. In addition, the wear detection device records certain operating parameters of the vacuum pump as operating variables, which include the temperature and the speed of the vacuum pump.The respective value of the operating parameter can be recorded over a predetermined period of time in order to relate the wear indicator to the values ​​of the operating parameter recorded in this way. The values ​​of the operating parameter recorded over the predetermined period of time can, for example, be summed, integrated, or otherwise offset against one another in order to obtain, for example, an average value for the operating parameter, based on which the respective wear indicator can be determined. Furthermore, it is also possible for the wear detection device to record the condition of a specific operating component of the vacuum pump and assign this condition to another wear indicator. Such a condition of the operating component can, for example, include the temperature of a coolant of the vacuum pump and / or the quality of certain lubricants.

[0013] The respective wear indicator thus assumes a specific numerical value derived from the operating hours, optionally also from fault events, and from other recorded operating parameters of the vacuum pump. A predetermined state of the wear indicator, which triggers the measure to reduce wear in the vacuum pump by means of the protective device, in this case involves the numerical value of the wear indicator exceeding a predetermined threshold. A further wear indicator can be directly assigned to a specific state of an operating component of the vacuum pump, so that the state of the operating component, e.g., exceeding a certain temperature of the coolant of the vacuum pump, directly triggers the measure to reduce wear.

[0014] The measure to reduce wear on the vacuum pump can include adjusting certain operating parameters of the vacuum pump in such a way that wear on the vacuum pump components is reduced. For example, the maximum possible speed can be reduced to allow the vacuum pump to continue operating without, for example, damaging its rolling bearings or safety bearings.

[0015] The vacuum pump according to the invention is thus characterized in that not only is the wear of the vacuum pump components recorded, among other things by counting operating hours, but that, in addition, a suitable measure to reduce wear is triggered based on the wear indicators. By determining the wear indicator based on the operating parameters of the vacuum pump, a careful diagnosis of the vacuum pump is also carried out. This makes it possible, for example, to issue a warning before an actual impairment or even failure of the vacuum pump and thus of the system in which the vacuum pump is integrated occurs. By triggering the measure to reduce wear on the vacuum pump, its operation can be expanded or its operating life can be extended, even if this operation is associated with restrictions due to the measure, which are, however, tolerable under certain circumstances.Overall, a failure of the vacuum pump due to wear of one of its components is avoided by detecting the wear at an early stage and initiating countermeasures to reduce or even prevent further wear of this component.

[0016] As already mentioned, the set of operating variables includes the operating time of the vacuum pump, and one of the wear indicators comprises a numerical value derived from the operating time of the vacuum pump. The operating time can be recorded from a previous maintenance of the vacuum pump, for example, if parts or components of the vacuum pump that are subject to wear are repaired or replaced during this maintenance. Alternatively, the entire operating time of the vacuum pump can be recorded. Specifically, the operating hours of the vacuum pump are counted, so that the numerical value of the operating hours represents the corresponding wear indicator. The number of operating hours is compared with a predetermined threshold value, which is assigned a certain probability that wear of at least one component of the vacuum pump could lead to a malfunction or even failure of the vacuum pump within a relatively short period of time.Such a threshold can be configurable, meaning that the threshold can be adapted to the specific type of vacuum pump and the environment in which the vacuum pump is used. Furthermore, recording the operating time of the vacuum pump can be relatively straightforward, since, for example, many vacuum pumps already have their operating hours counted.

[0017] In addition, the set of operating variables includes operating parameters of the vacuum pump. The wear detection device is designed to determine the wear indicator by recording values ​​of the operating parameter over a predetermined period of time and relating them to the wear indicator. The operating parameter includes a temperature within a predetermined range of the vacuum pump and a vibration of the vacuum pump. For example, a period of time during which the temperature of the vacuum pump is above a predetermined limit can be recorded. The intensity of the vibrations and optionally also frequencies and / or the amplitude of the vibrations of the vacuum pump can be recorded over a predetermined period of time.

[0018] If the amplitude of the vibrations is cumulative for a certain

[0019] If the vibration frequency exceeds a predetermined limit for a certain period of time and / or predetermined characteristics are evident in the vibration frequencies, this may be associated with increased wear in one or more components of the vacuum pump, such as its rolling bearings. The measurement of the vacuum pump's vibrations can therefore be assigned to a corresponding wear indicator.

[0020] Furthermore, the pressure and speed, as well as optionally one or more speed / pressure cycles and / or a gas flow in the vacuum pump, are recorded as part of the set of vacuum pump operating variables. By recording these operating variables over a predetermined period of time, it can be determined whether increased wear has occurred in a specific area or on a specific component of the vacuum pump.

[0021] In addition, the set of operating variables can include a state of at least one operating component of the vacuum pump. In this case, the wear detection device can be designed to determine an additional wear indicator based on the state of the at least one operating component. The state of the operating component can, in particular, include the temperature of a coolant and / or the quality of a lubricant for at least one component of the vacuum pump. In such an embodiment, the wear of a component of the vacuum pump can thus be detected indirectly based on the interaction of the component with the operating component. In other words, increased wear of a specific component of the vacuum pump can be associated with a change in the state of the at least one operating component, such that this change in the state of the operating component can be used as a wear indicator.For example, a change in the temperature of the coolant and / or a reduction in the quality of the lubricant, which can be detected, for example, by clouding of the lubricating oil of a vacuum pump, can be indicators of wear of the component of the vacuum pump for which the coolant or lubricant is intended.

[0022] In order to detect wear on one or more components of the vacuum pump, i.e. in particular the rolling bearing, in a timely and reliable manner, the set of operating variables comprises several operating variables that are recorded simultaneously. As mentioned, the set of operating variables includes the operating time of the vacuum pump, several operating parameters such as, among others, the temperature and vibrations of the vacuum pump and, optionally, the condition of a coolant or lubricant. Each of these operating variables is assigned a respective wear indicator. The protective device is designed to carry out one or more measures to reduce wear on the vacuum pump as soon as at least one of the plurality of wear indicators assumes a predetermined state, i.e. exceeds a certain threshold value.Since the set of operating variables includes several operating variables, it can be ensured that the measure to reduce the wear of the vacuum pump is carried out in a timely manner and that, on the other hand, maintenance of the vacuum pump is not carried out unnecessarily too early.

[0023] Furthermore, the protective device is designed to implement the measure for reducing wear on the vacuum pump in such a way that the power consumption of the vacuum pump is limited. By limiting the power consumption of the vacuum pump, for example, its temperature, vibrations, and / or mechanical load can be limited in such a way that additional wear on one or more components of the vacuum pump is eliminated or at least reduced. Limiting the power consumption can reduce the maximum possible speed of the vacuum pump.

[0024] A process carried out in a vacuum system in which the vacuum pump is installed may be limited by the reduced power consumption of the vacuum pump. Such a limitation may be tolerable, so that the process can still be carried out despite the reduced power consumption. However, by taking measures to reduce wear on the vacuum pump, the available operating time of the vacuum pump can be extended, so that the process can still be carried out despite the reduced power consumption. Conversely, by reducing the power consumption of the vacuum pump, the available operating time of the vacuum pump can enable the process to continue to be carried out and completed, which might not be guaranteed without reducing the power consumption of the vacuum pump due to the additional wear on the vacuum pump.However, if the process can no longer be carried out correctly due to the power consumption limitation, for example, because the pressure in a vacuum chamber connected to the vacuum pump increases due to a reduction in the speed of the vacuum pump, a warning can be issued. This allows an operator of the process or vacuum system to recognize that correct execution of the process is no longer guaranteed and the process should be terminated.

[0025] The measure for reducing wear on the vacuum pump can further be implemented by limiting the use of operating reserves that are not taken into account during normal operation of the vacuum pump and typically only play a role during transitions between operating states of the vacuum pump. For example, if a vacuum pump is required to transition from a previous operating point to a new operating point with respect to the pressure in a chamber connected to the vacuum pump, reducing the maximum power consumption of the vacuum pump can result in the vacuum pump requiring a longer period of time for the transition phase between the two operating points, i.e., compared to the period that would be required without limiting the maximum power consumption.In such a case, a corresponding process carried out in the vacuum system with the vacuum chamber may not be affected by limiting the maximum power consumption of the vacuum pump, or the limitation of the maximum power consumption of the vacuum pump may merely result in an extension of individual process steps. This may be tolerable as long as the process itself is fully feasible.

[0026] The protective device can further be designed to carry out the measure for reducing wear on the vacuum pump in such a way that at least one limit value for outputting a warning and / or an error message for at least one of the operating variables is reduced. In other words, due to the wear of a component of the vacuum pump, which is detected by means of the respective wear indicator, the warning and / or error message is output earlier, i.e. at a lower limit value, than during normal operation. In this case, the wear indicator can indicate that the vacuum pump has a lower load capacity due to the wear of at least one component and should, for example, be switched off when the reduced limit value of a specific operating variable is reached.

[0027] The protective device can additionally be configured to implement the measure for reducing wear on the vacuum pump by adjusting the state of at least one operating medium of the vacuum pump. For example, the amount of an available operating medium, such as a coolant and / or lubricant, can be increased or decreased depending on the temperature of the vacuum pump in order to counteract additional wear on a component of the vacuum pump.

[0028] A further aspect of the invention relates to a method for operating a vacuum pump. According to the method, a set of operating variables of the vacuum pump is detected by means of a wear detection device, and for each of the detected operating variables, a respective wear indicator for the vacuum pump is determined, which indicates the wear of a component of the vacuum pump. If at least one of the wear indicators exceeds a predetermined threshold value, a measure for reducing the wear of the vacuum pump is carried out by means of a protective device. A predetermined condition for triggering the measure thus includes one of the wear indicators having a numerical value that is greater than a respective predetermined threshold value.

[0029] The vacuum pump described above is therefore intended to carry out the steps of the method by means of the wear detection device and the protective device. The above statements regarding the vacuum pump according to the invention therefore also apply mutatis mutandis to the method according to the invention, in particular with regard to the disclosure, the advantages, and the preferred embodiments.

[0030] The set of operating variables includes the operating time of the vacuum pump, and a numerical value of one of the wear indicators is derived from the operating time of the vacuum pump. Determining the operating time of the vacuum pump involves counting its operating hours.

[0031] The set of operating variables additionally includes several operating parameters of the vacuum pump. In this case, the respective wear indicator can be determined by recording values ​​of the operating parameter over a predetermined period of time and relating them to the wear indicator. The operating parameters include the temperature of the vacuum pump and a vibration intensity, and optionally also an amplitude or frequency characteristics of vibrations of the vacuum pump, which can be recorded cumulatively. The operating parameters further include a pressure and a speed of a rotor of the vacuum pump, as well as optionally one or more speed / pressure cycles and / or a gas flow in the vacuum pump.

[0032] Additionally, the set of operating variables can include a condition of at least one operating component of the vacuum pump. In this case, an additional wear indicator can be determined based on the condition of the at least one operating component. The condition of the operating component can include, for example, the temperature of a coolant for the vacuum pump and / or the quality of a lubricant for at least one component of the vacuum pump.

[0033] The measure for reducing wear on the vacuum pump is implemented by means of the protective device in such a way that the power consumption of the vacuum pump is limited. The measure for reducing wear on the vacuum pump can additionally be implemented in such a way that at least one limit value for outputting a maintenance and / or error message for at least one of the operating variables is reduced. In addition, the measure for reducing wear on the vacuum pump can be implemented by adjusting a state of at least one operating component of the vacuum pump. Adjusting the state of the operating component can comprise increasing or decreasing an available quantity of operating component for a component of the vacuum pump in order to thereby reduce wear on the component.

[0034] The invention is described below by way of example using advantageous embodiments with reference to the accompanying figures. They show, schematically: Fig. 1a perspective view of a turbomolecular pump, Fig. 2a view of the underside of the turbomolecular pump of Fig. 1 , Fig. 3 a cross-section of the turbomolecular pump along the Fig. 2 shown section line AA, Fig. 4 a cross-sectional view of the turbomolecular pump along the Fig. 2 shown section line BB, Fig. 5 a cross-sectional view of the turbomolecular pump along the Fig. 2 shown section line CC, Fig. 6 a block diagram of a vacuum pump according to the invention and Fig. 7 a flow diagram of a method according to the invention.

[0035] The Fig. 1The turbomolecular pump 111 shown comprises a pump inlet 115 surrounded by an inlet flange 113, to which a recipient (not shown) can be connected in a manner known per se. The gas from the recipient can be sucked out of the recipient via the pump inlet 115 and conveyed through the pump to a pump outlet 117, to which a backing pump, such as a rotary vane pump, can be connected.

[0036] The inlet flange 113 forms the vacuum pump alignment according to Fig. 1 the upper end of the housing 119 of the vacuum pump 111. The housing 119 comprises a lower part 121, on which an electronics housing 123 is arranged laterally. Electrical and / or electronic components of the vacuum pump 111 are housed in the electronics housing 123, e.g., for operating an electric motor 125 arranged in the vacuum pump (see also Fig. 3). Several connectors 127 for accessories are provided on the electronics housing 123. In addition, a data interface 129, e.g., according to the RS485 standard, and a power supply connector 131 are arranged on the electronics housing 123.

[0037] There are also turbomolecular pumps that do not have such an attached electronics housing, but are connected to external drive electronics.

[0038] On the housing 119 of the turbomolecular pump 111, a flooding inlet 133, in particular in the form of a flooding valve, is provided, via which the vacuum pump 111 can be flooded. In the area of ​​the lower part 121, a sealing gas connection 135, which is also referred to as a purge gas connection, is also arranged, via which purge gas is supplied to protect the electric motor 125 (see e.g. Fig. 3) can be admitted into the motor compartment 137, in which the electric motor 125 is housed in the vacuum pump 111, before the gas delivered by the pump. Furthermore, two coolant connections 139 are arranged in the lower part 121, one of which serves as an inlet and the other as an outlet for coolant, which can be fed into the vacuum pump for cooling purposes. Other existing turbomolecular vacuum pumps (not shown) are operated exclusively with air cooling.

[0039] The lower side 141 of the vacuum pump can serve as a base, so that the vacuum pump 111 can be operated standing on the underside 141. However, the vacuum pump 111 can also be attached to a recipient via the inlet flange 113 and thus operated in a suspended position. Furthermore, the vacuum pump 111 can be designed so that it can also be operated when oriented in a different manner than in Fig. 1 As shown. Embodiments of the vacuum pump can also be realized in which the underside 141 is arranged facing either sideways or upwards, rather than downwards. In principle, any angle is possible.

[0040] Other existing turbomolecular vacuum pumps (not shown), which are particularly larger than the pump shown here, cannot be operated in an upright position.

[0041] 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 together. For example, a bearing cover 145 is attached to the underside 141.

[0042] Mounting holes 147 are also arranged on the underside 141, through which the pump 111 can be attached, for example, to a support surface. This is not possible with other existing turbomolecular vacuum pumps (not shown), which are particularly larger than the pump shown here.

[0043] In the Figures 2 to 5 a coolant line 148 is shown in which the coolant introduced and discharged via the coolant connections 139 can circulate.

[0044] As the sectional views of the Figures 3 to 5 show, 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.

[0045] A rotor 149 is arranged in the housing 119 and has a rotor shaft 153 rotatable about a rotation axis 151.

[0046] The turbomolecular pump 111 comprises several turbomolecular pump stages connected in series for pumping purposes, with several radial rotor disks 155 attached to the rotor shaft 153 and stator disks 157 arranged between the rotor disks 155 and secured in the housing 119. A rotor disk 155 and an adjacent stator disk 157 each form a turbomolecular pump stage. The stator disks 157 are held at a desired axial distance from one another by spacer rings 159.

[0047] The vacuum pump also includes Holweck pump stages arranged radially one inside the other and connected in series for pumping efficiency. Other turbomolecular vacuum pumps (not shown) exist that do not have Holweck pump stages.

[0048] The rotor of the Holweck pump stages comprises a rotor hub 161 arranged on the rotor shaft 153 and two cylindrical-shell-shaped Holweck rotor sleeves 163, 165 attached to and supported by the rotor hub 161, which are oriented coaxially to the rotational axis 151 and nested within one another in the radial direction. Furthermore, two cylindrical-shell-shaped Holweck stator sleeves 167, 169 are provided, which are also oriented coaxially to the rotational axis 151 and nested within one another in the radial direction.

[0049] The pumping surfaces of the Holweck pump stages are formed by the lateral 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 lies opposite the radial outer surface of the outer Holweck rotor sleeve 163, forming a radial Holweck gap 171, and together with the latter forms the first Holweck pump stage following the turbomolecular pumps. The radial inner surface of the outer Holweck rotor sleeve 163 lies opposite the radial outer surface of the inner Holweck stator sleeve 169, forming a radial Holweck gap 173, and together with the latter forms a second Holweck pump stage. The radial inner surface of the inner Holweck stator sleeve 169 lies opposite the radial outer surface of the inner Holweck rotor sleeve 165, forming a radial Holweck gap 175 and together forming the third Holweck pumping stage.

[0050] At the lower end of the Holweck rotor sleeve 163, a radially extending channel can be provided, via which the radially outer Holweck gap 171 is connected to the central Holweck gap 173. Furthermore, at the upper end of the inner Holweck stator sleeve 169, a radially extending channel can be provided, via which the central Holweck gap 173 is connected to the radially inner Holweck gap 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.

[0051] The above-mentioned pump-active surfaces of the Holweck stator sleeves 167, 169 each have a plurality of Holweck grooves extending spirally around the rotation axis 151 in the axial direction, while the opposite lateral surfaces of the Holweck rotor sleeves 163, 165 are smooth and propel the gas in the Holweck grooves for operating the vacuum pump 111.

[0052] 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.

[0053] In the area of ​​the rolling bearing 181, a conical spray nut 185 with an outer diameter increasing toward the rolling bearing 181 is provided on the rotor shaft 153. The spray nut 185 is in sliding contact with at least one wiper of a fluid reservoir. In other existing turbomolecular vacuum pumps (not shown), a spray screw can be provided instead of a spray nut. Since different designs are thus possible, the term "spray tip" is also used in this context.

[0054] The operating fluid storage comprises several stacked absorbent discs 187, which are impregnated with an operating fluid for the rolling bearing 181, e.g. with a lubricant.

[0055] During operation of the vacuum pump 111, the operating fluid is transferred by capillary action from the operating fluid reservoir via the wiper to the rotating injection nut 185. As a result of centrifugal force, it is conveyed along the injection nut 185 in the direction of the increasing outer diameter of the injection nut 185 to the rolling bearing 181, where it fulfills a lubricating function, for example. The rolling bearing 181 and the operating fluid reservoir are enclosed in the vacuum pump by a trough-shaped insert 189 and the bearing cover 145.

[0056] The permanent magnet bearing 183 comprises a rotor-side bearing half 191 and a stator-side bearing half 193, each comprising a ring stack of several permanent magnetic rings 195, 197 stacked one on top of the other in the axial direction. The ring magnets 195, 197 lie opposite one another, forming a radial bearing gap 199, with the rotor-side ring magnets 195 being arranged radially on the outside and the stator-side ring magnets 197 being arranged radially on the inside. The magnetic field present in the bearing gap 199 creates magnetic repulsion forces between the ring magnets 195, 197, which effect a radial bearing of the rotor shaft 153. The rotor-side ring magnets 195 are carried by a support section 201 of the rotor shaft 153, which surrounds the ring magnets 195 on the radial outside.The stator-side ring magnets 197 are supported by a stator-side support section 203, which extends through the ring magnets 197 and is suspended from radial struts 205 of the housing 119. The rotor-side ring magnets 195 are secured parallel to the rotation axis 151 by a cover element 207 coupled to the support section 201. The stator-side ring magnets 197 are secured parallel to the rotation axis 151 in one direction by a fastening ring 209 connected to the support section 203 and a fastening ring 211 connected to the support section 203. A disc spring 213 can also be provided between the fastening ring 211 and the ring magnets 197.

[0057] Within the magnetic bearing, an emergency or backup bearing 215 is provided, which runs idle without contact during normal operation of the vacuum pump 111 and only engages upon excessive radial deflection of the rotor 149 relative to the stator, forming a radial stop for the rotor 149 to prevent collision of the rotor-side structures with the stator-side structures. The backup bearing 215 is designed as an unlubricated rolling bearing and forms a radial gap with the rotor 149 and / or the stator, causing the backup bearing 215 to be disengaged during normal pumping operation. The radial deflection at which the backup bearing 215 engages is large enough so that the backup bearing 215 does not engage during normal operation of the vacuum pump, yet small enough so that collision of the rotor-side structures with the stator-side structures is prevented under all circumstances.

[0058] 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 portion of the rotor shaft 153 extending through the motor stator 217. Between the motor stator 217 and the portion of the rotor 149 extending through the motor stator 217, an intermediate space 219 is arranged, which comprises a radial motor gap, via which the motor stator 217 and the permanent magnet arrangement can magnetically influence each other to transmit the drive torque.

[0059] The motor stator 217 is secured in the housing within the motor compartment 137 provided for the electric motor 125. A purge gas, also referred to as a purge gas, which may be air or nitrogen, for example, can enter the motor compartment 137 via the purge gas connection 135. The purge gas can be used to protect 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, i.e., the vacuum pressure in the motor compartment 137 is at least approximately equal to the vacuum pressure created by the backing pump connected to the pump outlet 117.

[0060] Furthermore, a so-called labyrinth seal 223, which is known per se, can be provided between the rotor hub 161 and a wall 221 delimiting the motor compartment 137, in particular in order to achieve a better sealing of the motor compartment 217 with respect to the Holweck pump stages located radially outside.

[0061] Fig. 6 shows a schematic block diagram of a vacuum pump 600, which is, for example, the one shown in Fig. 1 to 5 The vacuum pump 600 includes components 610 known to be potentially subject to wear during operation of the vacuum pump 600. In the case of the turbomolecular pump 111, the components 610 include the rolling bearing 181 (see Fig. 3 to 5 ) and the emergency or detention camp 215 (cf. Fig. 3 ) as well as all previously described parts of the turbomolecular pump 111 that are movable during its operation. The components 610 can also, on the one hand, be the movable parts of the electric motor 125 (cf. Fig. 3) and, on the other hand, those electrical and electronic elements of the electric motor 125 which are subjected to a particular load during operation of the turbomolecular pump 111, for example an increased temperature and / or a high voltage and / or a high current.

[0062] The vacuum pump 600 further comprises a wear detection device 620, which is connected to the components 610 of the vacuum pump 600 in order to record a set of operating variables of the vacuum pump 600 and, based on the recorded operating variables, to determine at least one wear indicator for the vacuum pump 600, which indicates the wear of at least one component 610 of the vacuum pump 600. If the vacuum pump 600 is the turbomolecular pump 111, the wear detection device 620 records the operating time of the vacuum pump 600 or the turbomolecular pump 111 through a communicative connection with the electric motor 125 as the first element of the set of operating variables. Based on the operating time of the vacuum pump 600, the wear detection device 620 derives a numerical value that is used as a wear indicator of the vacuum pump 600.

[0063] The wear detection device 620 further detects, as additional operating variables, operating parameters of the vacuum pump 600. In the case of the turbomolecular pump 111, these include its temperature, the pressure on its high-vacuum side, the speed of the rotor 149, one or more speed / pressure cycles, and vibrations of the turbomolecular pump 111, the latter being measured using a vibration sensor (not shown). Based on these detected operating parameters of the vacuum pump 600 or the turbomolecular pump 111, the wear detection device 620 in turn determines a respective wear indicator that is specific to and associated with each of the aforementioned operating parameters. Values ​​of the respective operating variables are detected over a predetermined period of time and compared with a respective threshold value to determine whether one or more of the components 610 of the vacuum pump 600 are subject to increased wear.The wear indicator is thus correlated with the recorded values ​​of the operating parameter. The operating parameter values ​​recorded over the predetermined period are, for example, summed, integrated, or otherwise calculated to obtain an average value for the operating parameter, which is used to determine the wear indicator.

[0064] The wear detection device 620 further detects a condition of at least one operating component of the vacuum pump 600, for example, in the case of the turbomolecular pump 111, the quality of a lubricant for those components of the turbomolecular pump 111 that require lubrication. The quality of the lubricant can be detected, for example, by monitoring one or more physical and / or chemical properties of the lubricant, e.g., the presence of a specific substance in the lubricant, its viscosity, and / or its optical properties.

[0065] The vacuum pump 600 also includes a protective device 630, which is designed to implement a measure for reducing wear on the vacuum pump 600 when the at least one wear indicator assumes a predetermined state. The wear detection device 620 communicates with the protective device 630 and transmits the respective wear indicators of the various operating variables of the vacuum pump 600 to the protective device 630. The state of the respective wear indicator, based on which the protective device 630 triggers the measure for reducing wear on the vacuum pump 600, is determined in the case of the operating time and the operating parameters by their values ​​exceeding a respective predetermined threshold value.For the operating resources of the vacuum pump 600, a predefined state of the operating resource is assigned to the state of the wear indicator that triggers the measure to reduce the wear of the vacuum pump 600.

[0066] In the case of the turbomolecular pump 111, this measure includes limiting the power consumption of the turbomolecular pump 111. This also limits the maximum achievable speed of the rotor 149 of the turbomolecular pump 111. By limiting the maximum speed of the rotor 149, the wear of the rolling bearing 181 (see Fig. 3 to 5 ) and also the emergency or detention camp 215 (cf. Fig. 3 ) which would otherwise occur if the turbomolecular pump 111 continued to operate at its rated speed.

[0067] Fig. 7shows a schematic flow diagram of a method 700 for operating the vacuum pump 600, i.e., in particular, the turbomolecular pump 111. At 710, a set of operating variables of the vacuum pump 600 is detected by means of the wear detection device 620, which are each assigned to the various components 610 of the vacuum pump 600. In the case of the turbomolecular pump 111, the operating variables include, among other things, the number of operating hours of the turbomolecular pump 111, the temperature, the speed of the rotor 149, and the pressure in the turbomolecular pump 111.

[0068] At 720, the wear detection device 620 uses the detected operating variables to determine a respective wear indicator for the vacuum pump 600, which indicates the wear of one or more components 610 of the vacuum pump 600. At 730, a check is made to determine whether at least one of the wear indicators assumes a predetermined state, i.e., by exceeding a predetermined threshold value. If this is not the case, the method returns to step 710 to continue monitoring the operating variables of the vacuum pump 600 and to detect a new set of operating variables.

[0069] However, if at least one of the wear indicators determined at 720 assumes the predetermined state indicating increased wear of one or more components 610, a measure to reduce the wear of the vacuum pump 600 is carried out at 740 by means of the protective device. In the case of the turbomolecular pump 111, one of these measures consists in limiting the power consumption of the turbomolecular pump 111 in order to thereby limit the maximum speed of the rotor 149 and the rolling bearing 181 (cf. Fig. 3 to 5 ) and the emergency or detention camp 215 (cf. Fig. 3 ) to protect. List of reference symbols

[0070] 111Turbomolecular pump 113Inlet flange 115Pump inlet 117Pump outlet 119Housing 121Lower section 123Electronics housing 125Electric motor 127Accessory connection 129Data interface 131Power supply connection 133Flood inlet 135Seal gas connection 137Motor compartment 139Coolant connection 141Underside 143Screw 145Bearing cover 147Mounting hole 148Coolant line 149Rotor 151Rotation axis 153Rotor shaft 155Rotor disc 157Stator disc 159Spacer ring 161Rotor hub 163Holweck rotor sleeve 165Holweck rotor sleeve 167Holweck stator sleeve 169Holweck stator sleeve 171Holweck gap 173Holweck gap 175Holweck gap 179Connecting channel 181Rolling bearing 183Permanent magnet bearing 185Injection nut 187Disc 189Insert 191Rotor-side bearing half 193Stator-side bearing half 195Ring magnet 197Ring magnet 199Bearing gap 201Support section 203Support section 205Radial strut 207Cover element 209Support ring 211Fastening ring 213Disc spring 215Emergency orSafety bearing 217Motor stator 219Gap 221Wall 223Labyrinth seal 600Vacuum pump 610Vacuum pump component 620Wear detection device 630Protective device 700Procedure for operating the vacuum pump 710-740Procedure steps.

Claims

1. A vacuum pump (111) comprising: - a wear recognition device (620) which is configured to detect a set of operating variables of the vacuum pump (111) and to determine a respective wear indicator for the vacuum pump (111) for each of the detected operating variables, said wear indicator indicating the wear of at least one component (610) of the vacuum pump (111), wherein the at least one component (610) can in particular be a rolling element bearing (181) of the vacuum pump (111), wherein the respective wear indicator assumes a respective numerical value which is derived from the respective operating variable of the vacuum pump (111); and - a protection device (630), characterized in that the protection device (630) is configured to carry out a measure for reducing the wear of the vacuum pump (111) when at least one of the wear indicators assumes a predetermined state, i.e. exceeds a respective predetermined threshold value, wherein the set of operating variables comprises a number of operating hours of the vacuum pump (111), a temperature of the vacuum pump (111), a rotational speed of the vacuum pump (111), a pressure in the vacuum pump (111) and an intensity of vibrations of the vacuum pump (111), and wherein the protection device (630) is configured to carry out the measure for reducing the wear of the vacuum pump (111) such that a power consumption of the vacuum pump (111) is limited.

2. A vacuum pump (111) according to claim 1, wherein the set of operating variables further comprises a state of at least one operating medium of the vacuum pump (111) and the wear recognition device (620) is configured to determine a further wear indicator based on the state of the at least one operating medium.

3. A vacuum pump (111) according to claim 2, wherein the state of the operating medium comprises the temperature of a coolant and / or the quality of a lubricant for the at least one component (610) of the vacuum pump (111).

4. A vacuum pump (111) according to any one of the claims 1 to 3, wherein the protection device (630) is configured to carry out the measure for reducing the wear of the vacuum pump (111) such that at least one limit value for outputting a warning and / or an error message for at least one of the operating variables is reduced.

5. A vacuum pump (111) according to any one of the claims 1 to 4, wherein the protection device (630) is configured to carry out the measure for reducing the wear of the vacuum pump (111) by adjusting a state of at least one operating medium of the vacuum pump (111).

6. A method (700) for operating a vacuum pump (111), wherein the method comprises that a set of operating variables of the vacuum pump (111) is detected by means of a wear recognition device (620) and a respective wear indicator for the vacuum pump (111) is determined for each of the detected operating variables, said wear indicator indicating the wear of at least one component (610) of the vacuum pump (111), wherein the at least one component (610) can in particular be a rolling element bearing (181) of the vacuum pump (111), wherein the respective wear indicator assumes a respective numerical value which is derived from the respective operating variable of the vacuum pump (111), and a measure for reducing the wear of the vacuum pump (111) is carried out by means of a protection device (630) if at least one of the wear indicators assumes a predetermined state, i.e. exceeds a respective predetermined threshold value, wherein the set of operating variables comprises a number of operating hours of the vacuum pump (111), a temperature of the vacuum pump (111), a rotational speed of the vacuum pump (111), a pressure in the vacuum pump (111) and an intensity of vibrations of the vacuum pump (111), and wherein the measure for reducing the wear of the vacuum pump (111) is carried out by means of the protection device (630) such that a power consumption of the vacuum pump (111) is limited.

7. A method (700) according to claim 6, wherein the set of operating variables further comprises a state of at least one operating medium of the vacuum pump (111) and a further wear indicator is determined based on the state of the at least one operating medium.

8. A method (700) according to claim 6 or 7, wherein the measure for reducing the wear of the vacuum pump (111) is carried out such that at least one limit value for outputting a warning and / or an error message for at least one of the operating variables is reduced.

9. A method (700) according to any one of the claims 6 to 8, wherein the measure for reducing the wear of the vacuum pump (111) is carried out by adjusting a state of at least one operating medium of the vacuum pump (111).

Images