Vacuum pump

Abstract

A vacuum pump comprises a sensor arranged on a first component of the vacuum pump and configured to measure a physical property of the first component, and an RFID transponder attached to the first component and communicatively connected to the sensor. The vacuum pump further comprises an RFID reader attached to a second component of the vacuum pump, which is different from the first component, at a distance relative to the RFID transponder such that the RFID reader and the RFID transponder are communicatively connected. A method for operating such a vacuum pump is also described.

Description

[0001] The invention relates to a vacuum pump with a sensor which is arranged on a component of the vacuum pump and is designed to measure a physical property of this component, as well as to a method for operating such a vacuum pump.

[0002] During operation of a vacuum pump, it is necessary to record certain physical properties of the vacuum pump's components. Examples of such properties include the temperature of a vacuum pump's rotor or its rotational speed. Recording such properties is essential to achieve the best possible performance while simultaneously maintaining the required operational reliability and durability of the vacuum pump over the long term.

[0003] Non-contact measurement methods are often used to measure the physical or chemical properties of rapidly rotating vacuum pump components, such as the physical or chemical properties of a rotor shaft. For example, a pyrometer with thermal or photoelectric detectors can be used to measure the temperature of a rotor shaft. However, to reliably determine the temperature of the rotor shaft, the emissivity of a measuring surface on the rotor shaft, which is detected by the pyrometer, must be precisely known. Furthermore, it is often assumed that a measurement parameter such as the emissivity of the measuring surface does not change during operation of the vacuum pump. However, this assumption may not be correct under the specific operating conditions of the vacuum pump.For example, due to the properties of the gases to be pumped, a coating may occur on the surfaces of the vacuum pump, which changes the emissivity of the measuring surface.

[0004] Alternatively, performance curves can be used to indirectly measure the temperature of the vacuum pump's rotor, in which the rotor temperature is assigned to a specific power consumption of the vacuum pump. In addition, magnetic-inductive measurement methods can be used to indirectly measure the rotor temperature.

[0005] The known non-contact measurement methods for specific physical or chemical properties of vacuum pump components therefore usually require certain assumptions, for example, regarding the temporal constancy of known measurement parameters, as explained above. Furthermore, the known non-contact measurement methods usually require specific calibration of the vacuum pump before it can be delivered, which can be associated with considerable costs. Furthermore, the known non-contact measurement methods can be surface-sensitive, and their reliability can depend on the respective operating situation or the current load of the vacuum pump.

[0006] An object of the invention is to provide a vacuum pump and a method for operating such a vacuum pump with which a contactless measurement of a predetermined physical or chemical property of a component of the vacuum pump is possible in a reliable manner without complex calibration.

[0007] 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.

[0008] The vacuum pump comprises a sensor arranged on a first component of the vacuum pump and configured to measure a physical property of the first component, and an RFID transponder attached to the first component and communicatively connected to the sensor. The RFID transponder is a device with a transmitter and receiver for identification that operates in the radio frequency range (RFID). The vacuum pump further comprises an RFID reader attached to a second component of the vacuum pump, which is different from the first component, at a distance from the RFID transponder such that the RFID reader and the RFID transponder are communicatively connected.

[0009] The vacuum pump can be, for example, a turbomolecular pump, and the first component can be, for example, a rotor of such a turbomolecular pump. However, the first component can also be another, hard-to-access, non-rotating component of the vacuum pump. The sensor can be, for example, a temperature sensor attached to a rotor of a turbomolecular pump, or another sensor such as a gyroscope or a strain gauge.

[0010] The RFID transponder and the RFID reader form an RFID system that, on the one hand, identifies the RFID transponder by storing a unique identifier on a microchip of the RFID transponder, for example. This unique identifier is retrieved via a query signal from the RFID reader after the RFID transponder has been woken up and sent to the RFID reader. This identification ensures that the RFID reader is in communication with the desired RFID transponder and not with any other device.

[0011] The RFID transponder and sensor preferably do not require their own energy storage devices, such as a battery. Instead, the RFID transponder and sensor can be powered by electromagnetic waves emitted by the RFID reader. Signals transmitted by the RFID reader, such as the aforementioned query signal or other signals, can be received and rectified by the RFID transponder to supply the RFID transponder and sensor with energy using such a rectified signal.

[0012] Since the RFID transponder and the sensor are both attached to the first component, for example, to a rotor of a turbomolecular pump, and are communicatively connected, measured values ​​from the sensor, which represent the physical property of the first component, can be transmitted from the sensor to the RFID transponder and from there to the RFID reader, which is also communicatively connected to the RFID transponder. The RFID reader can be configured to evaluate the acquired measured values ​​from the sensor and transmit corresponding information, e.g., regarding the temperature of a rotor of the vacuum pump, to a control device of the vacuum pump.

[0013] The use of the RFID transponder and the RFID reader thus allows for the wireless transmission or acquisition of measured values ​​of the physical property of the first component, for example, the temperature of the turbomolecular pump's rotor. Such wireless acquisition of the sensor's measured values ​​requires little effort, as no individual calibration of the entire system is required, for example, before delivery of the vacuum pump.

[0014] Furthermore, no additional assumptions are required regarding certain properties of the first component, such as the emissivity of a measuring surface in a pyrometric temperature measurement. Instead, the sensor can be pre-calibrated and positioned on the first component of the vacuum pump to perform a direct measurement of the physical property of the first component without any further assumptions. This allows for an accurate determination of the physical property of the first component.

[0015] The distance between the RFID reader and the RFID transponder is preferably selected such that an electrical oscillating circuit of the RFID transponder can be adjusted to a resonant frequency of the RFID communication between the RFID reader and the RFID transponder. If the distance is too large or if the geometry between the RFID transponder and the RFID reader changes, communication between them may no longer be possible.

[0016] According to one embodiment, the RFID transponder and the RFID reader are arranged adjacent to one another in an interior space of the vacuum pump. The interior space can be located within a housing of the vacuum pump and also preferably comprise the evacuated region of the vacuum pump. The RFID reader can therefore be connected to one or more vacuum feedthroughs, which, for example, enable communication between the RFID reader and a control unit of the vacuum pump and transmission of measured values ​​to the latter. The arrangement of the RFID transponder and the RFID reader in the interior space of the vacuum pump enables direct acquisition of measured values ​​of the physical property of the first component if the latter is arranged in the interior space of the vacuum pump and is possibly not accessible from the outside, i.e., from outside the housing of the vacuum pump.

[0017] The sensor can be integrated into the RFID transponder. Such a combination of the sensor and the RFID transponder requires little space and thus allows for flexible placement of the RFID transponder with integrated sensor on the first component.

[0018] Alternatively, the sensor and the RFID transponder can be arranged at a distance from one another on the first component. If the sensor detects the temperature of the first component, for example the temperature of a rotor of a vacuum pump, the temperature at the first component at a desired installation position of the sensor may be too high for the RFID transponder to operate. If the sensor is attached to a rotor of a turbomolecular pump, for example, temperatures greater than 85°C may occur at certain points on the rotor, at which operation of an RFID transponder with an integrated sensor is not possible. In such a case, only the sensor can be attached at the desired installation position, while the RFID transponder can be attached at a position where temperatures too high for its operation are not expected.When the sensor and the RFID transponder are arranged at a distance from each other on the first component, they can communicate with each other either wirelessly or via cable.

[0019] The RFID transponder can also be designed as a printed circuit board (PCB) embedded in the first component. In such an embodiment, the components of the RFID transponder can be integrated into the material of the printed circuit board and thus protected from high centrifugal forces, for example, if the first component is the rotor of the vacuum pump. In such a design, the components of the RFID transponder can first be applied to the printed circuit board using standardized manufacturing processes and then reinforced with a suitable potting compound, for example, based on a two-component epoxy. This provides additional protection for the components against the centrifugal forces that occur.

[0020] A shield can be arranged between the RFID transponder and the first component. Such a shield can comprise, for example, a ferrite layer. The shield can prevent electromagnetic losses in the material of the first component. If no shielding between the RFID transponder and the first component is desired, an alternative is to provide a sufficient distance of at least 2 to 3 mm between the RFID transponder and metallic surfaces within the vacuum pump, for example, in an axial direction along a rotor shaft of the vacuum pump.

[0021] The first component may comprise a rotating element of the vacuum pump to which the RFID transponder and the sensor are attached, while the second component may comprise a non-rotating element of the vacuum pump to which the RFID reader is attached. The rotating element may, for example, be a rotor of a turbomolecular pump, while the non-rotating element may be a stator of such a turbomolecular pump. The use of the RFID transponder and the RFID reader to transmit measured values ​​from the sensor thus allows for direct and cost-effective acquisition of measured values ​​of the physical properties of the rotating element or rotor, respectively, without additional effort and assumptions.

[0022] When installing the RFID transponder on the rotating element or rotor, the RFID transponder can be positioned as close as possible to the rotating element's rotational axis to minimize the centrifugal forces acting on the RFID transponder. Additionally, the RFID transponder can be armored to further protect the RFID transponder from the effects of centrifugal forces.

[0023] Elements or components of the RFID transponder and the sensor can also be arranged on the rotating element or rotor in such a way that any imbalances in the rotating element compensate for each other. In other words, the elements of the RFID transponder and the sensor can be distributed over the first component in such a way that the imbalance of the rotating element or rotor is minimized and ideally zero. Such an arrangement prevents malfunctions due to imbalance during operation of the vacuum pump.

[0024] The RFID transponder can also be integrated into the rotating element using a screw connection. This can allow for easy replacement of the RFID transponder.

[0025] The RFID reader can have integrated electronics. This can enable a compact design. The integrated electronics also allow the RFID reader to output previously analyzed data.

[0026] Alternatively or additionally, at least one electronic component associated with the RFID reader can be integrated into a control unit of the vacuum pump. This allows for a simple design of the RFID reader. However, in this case, an electrical connection between the electronic component and the RFID reader is required, for example, via a coaxial cable.

[0027] The RFID transponder and / or the RFID reader can further be configured to transmit a measurement signal from the sensor from the RFID transponder to the RFID reader by means of load modulation. Such load modulation involves switching a load resistor of the RFID transponder and / or the RFID reader on and off to achieve amplitude modulation.

[0028] By means of load modulation or switching the load resistor, a modulated signal can be generated at subcarrier frequencies, i.e., at frequencies outside the frequency bands typically used for RFID communication. The RFID reader can have a bandpass filter for those subcarrier frequencies at which the RFID transponder transmits the sensor's measurement signal, for example, using amplitude or load modulation. Such a bandpass filter ensures that the desired measurement signal and no interference signals are received by the RFID reader.

[0029] Furthermore, the RFID reader and the RFID transponder can each have an antenna, which can be concentrically circular or have a half-shell shape. Such antenna shapes can ensure secure data transmission between the RFID transponder and the RFID reader, even when the first component with the RFID transponder rotates rapidly relative to the second component with the RFID reader.

[0030] The invention further relates to a method for measuring a physical property of a first component in a vacuum pump, which has a sensor attached to the first component. According to the method, an RFID reader attached to a second component of the vacuum pump, which is different from the first component, sends a signal to an RFID transponder attached to the first component and in communicative connection with the sensor. The signal from the RFID reader is received by the RFID transponder in order to supply the RFID transponder and the sensor with energy. By means of the sensor, at least one measured value of the physical property of the first component is recorded and transmitted from the sensor to the RFID transponder.The at least one measured value is then transmitted from the RFID transponder to the RFID reader using load modulation in the RFID transponder and / or the RFID reader. The RFID reader can then evaluate the measured value.

[0031] The method is therefore intended for the operation of the vacuum pump described above in order to measure the physical property of the first component, for example, the temperature of a rotor of the vacuum pump, during this operation. Therefore, the above statements regarding the vacuum pump apply accordingly to the method, and this applies in particular with regard to the advantages and preferred embodiments. Furthermore, it is understood that all features mentioned herein can be combined with one another, unless explicitly stated otherwise.

[0032] The invention is described below by way of example using advantageous embodiments with reference to the accompanying figures. They show, schematically: Fig. 1 a sectional view of a section of a vacuum pump according to the invention, in which an RFID transponder and an RFID reader are arranged, Fig. 2 perspective views of the arrangement of Fig. 1 , Fig. 3 two versions of antennas for the RFID transponder and the RFID reader from Fig. 1 and 2 , Fig. 4 a sectional view of another section of a vacuum pump according to the invention, in which an RFID transponder and an RFID reader are arranged, and Fig. 5 a sectional view of a further section of a vacuum pump according to the invention with RFID transponder and an RFID reader.

[0033] Fig. 1 shows schematically a section of a vacuum pump 100, which is designed as a turbomolecular pump. The turbomolecular pump 100 comprises a rotor 110 with a rotor shaft 112 and several rotor disks, of which a rotor disk 114 is arranged in the region of a labyrinth seal 116 in Fig. 1 is shown.

[0034] Furthermore, the turbomolecular pump 110 comprises a stator 120, of which Fig. 1 However, only one labyrinth hub 122 is shown. The top of the labyrinth hub 122 and the bottom of the illustrated rotor disk 114 together form the labyrinth seal 116.

[0035] During operation of the turbomolecular pump 100, the rotor 110 rotates very rapidly relative to the stator 120, for example, at a speed of several tens of thousands of revolutions per minute. The rotor hub 112 and the rotor disk 114 are thus among the rotating components of the vacuum pump or turbomolecular pump 100, while the stator 120 with the labyrinth hub 122 are among the non-rotating components of the turbomolecular pump 100.

[0036] During operation of the turbomolecular pump 100, for example, it is necessary to record or measure physical or chemical properties of components of the turbomolecular pump 100 to ensure long-term operational stability. These properties include, for example, the temperature of the rotor 110.

[0037] To detect or measure the temperature of the rotor 110, the turbomolecular pump 110 includes an RFID transponder 130, which is attached to the rotor disk 114 by means of a screw connection 132. The RFID transponder 130 is also referred to as an RFID tag. A temperature sensor 134 is integrated into the RFID transponder 130. The counterpart to the RFID transponder is an RFID reader 140, which is attached to the labyrinth hub 122 of the stator 120, for example, by means of a screw connection or by gluing.

[0038] The RFID transponder 130 and the RFID reader 140 together form an RFID system, i.e., an identification system that operates in the radio frequency range (RFID). The RFID transponder 130 has a microchip on which a unique identifier is stored. Furthermore, the RFID transponder 130 is a passive device that does not include an energy storage device such as a battery. This means that the temperature sensor 134 also does not have its own energy source. Instead, the RFID transponder 130 and the temperature sensor 134 are powered by the RFID reader 140, i.e., by electromagnetic waves emitted by the RFID reader 140.

[0039] More specifically, the RFID reader 140 transmits an interrogation signal toward the RFID transponder 130 via an antenna, which is described in more detail below. The interrogation signal is received by an antenna of the RFID transponder 130 and serves, on the one hand, to activate or "wake up" the RFID transponder 130. Furthermore, the interrogation signal and / or other signals from the RFID reader 140 are converted by a rectifier of the RFID transponder 130 into signals for supplying power to both the RFID transponder 130 and the integrated temperature sensor 134.

[0040] In addition, the interrogation signal of the RFID reader 140 is read by the electronics of the RFID transponder 130 in order to send a signal containing the unique identifier of the RFID transponder 130 back to the RFID reader 140 in response to this signal. This ensures that correct communication takes place between the RFID transponder 130 and the RFID reader 140 and that no signals from other devices or interference signals are received by the latter.

[0041] The microchip of the RFID transponder 130 is used to capture measured values ​​or data from the integrated temperature sensor 134. In addition to the temperature sensor 134 on its microchip, the RFID transponder 130 includes a microcontroller and a voltage regulator, which are mounted on a common circuit board 300 (see FIG. Fig. 3 ) or are integrated into it together with an antenna 310.

[0042] The measured values ​​or data acquired by the temperature sensor 134 are transmitted to the RFID reader 140 via amplitude modulation of the electromagnetic field emitted by the RFID transponder 130. Amplitude modulation is achieved, for example, by switching a load resistor on and off, which is also referred to as load modulation. At frequencies used for RFID communication, such as 13.56 MHz, switching the additional load resistor generates signals of additional frequencies, i.e., so-called subcarrier frequencies. These subcarrier frequencies are used for data transmission between the RFID transponder 130 and the RFID reader 140.

[0043] The RFID reader 140 includes a bandpass filter for the subcarrier frequencies. By demodulating the signals received by the RFID reader 140, signals or data are generated that can be identified and interpreted as measurement data from the temperature sensor 134 by the electronics of the RFID reader 140. Consequently, in the present embodiment, evaluation electronics for the measurement data from the temperature sensor 134 are integrated into the RFID reader 140.

[0044] In detail, the RFID reader 140 includes an antenna for transmitting and receiving the signals described above, a high-frequency reader chip, a microcontroller, and a matching circuit, which includes, for example, coils and digitally tunable capacitors. The electronics of the RFID reader 140 serve, on the one hand, to regulate the transmission power of the antenna of the RFID reader 140 and to decode the modulated electromagnetic field in order to interpret the signals transmitted by the RFID transponder 130 as data from the temperature sensor 134.

[0045] The electronics of the RFID reader 140 are also connected to a drive electronics unit (not shown) of the vacuum pump 100, so that the drive electronics of the vacuum pump 100 can access the RFID reader 140 and the data provided by it. Known software protocols, for example, are used for such communication between the drive electronics of the vacuum pump and the RFID reader 140.

[0046] The RFID transponder 130 is arranged within the range of the RFID reader 140 to ensure wireless power transmission and data communication between the RFID transponder 130 and the RFID reader 140. The distance between the respective antennas of the RFID transponder 130 and the RFID reader 140 is typically in the range of a few millimeters. In the design of the antenna 310 (see Fig. 3 ) of the RFID transponder 130 requires a pump-specific adaptation of an electrical resonant circuit of the RFID transponder 130 to a resonant frequency of the RFID communication. In other words, such an electrical resonant circuit of the RFID transponder 130 is calibrated taking into account the given distance between the RFID transponder 130 and the RFID reader 140 or between their antennas.

[0047] The antennas of the RFID transponder 130 and the RFID reader 140 should also have a sufficient axial distance, ie along the rotor axis 112, ie in Fig. 1 in the vertical direction, relative to surfaces of other metallic components or parts of the vacuum pump 110, in order to prevent electromagnetic losses in the material of these components. Such a sufficient axial distance is, for example, 2 to 3 mm. If such a distance between the antennas of the RFID transponder 130 and the RFID reader 140 relative to metallic components of the vacuum pump 100 is to be undercut, suitable shielding, for example by means of a ferrite layer (not shown), is necessary.

[0048] Since the temperature sensor 134 is integrated into the RFID transponder 130, no further components are required to measure the temperature of the rotor 110, ie in addition to the RFID transponder 130 and the RFID reader 140. Since high centrifugal forces occur during operation of the turbomolecular pump 100 due to the high speeds of the rotor 110, the transponder 130 is arranged as close as possible to a rotational axis of the rotor shaft 112 (see also Fig. 2 ), ie radially in the area of ​​the inner diameter of the rotor disk 114, ie as close as possible to this inner diameter.

[0049] In order to additionally protect the transponder 130 including the integrated temperature sensor 134 against the centrifugal forces occurring during operation of the turbomolecular pump 100, the RFID transponder 130 including its antenna 310 and the temperature sensor 134 is designed as an embedded printed circuit board 300 or embedded PCB board (see also Fig. 2 and 3). The components of the RFID transponder 130, including the antenna and the temperature sensor 134, are integrated into the material of the circuit board 300 in order to protect these components, including the antenna 310 and the temperature sensor 134, from the high centrifugal forces.

[0050] The components of the RFID transponder 130 are applied to a PCB board, for example, using standardized manufacturing processes and reinforced with a suitable potting compound based on a two-component epoxy to achieve additional protection against the centrifugal forces that occur. Furthermore, a circuit board substrate and / or antenna substrate is advantageously used that has a suitably high yield strength with corresponding temperature stability at a specified temperature and a specified speed of the rotor 110 of the turbomolecular pump 100.

[0051] The temperature sensor 134 is designed as a digital temperature sensor, wherein the thermal coupling between the temperature sensor 134 and the rotor shaft 112 can be optimized, for example, by means of a "thermal pad" (i.e., by means of a solder contact for thermal coupling). With such an optimization, a copper line in the circuit board 300 of the RFID transponder 130 is guided to a position that has direct contact, for example, by means of a metallic contact surface, or indirect contact, for example, by means of a contact surface of a screw head when screwing the circuit board of the RFID transponder, with the material of the rotor shaft 112.

[0052] In addition to such a configuration with an already integrated temperature sensor 134, the temperature sensor 134 can also be implemented by a temperature-sensitive configuration of the antenna 310 of the RFID transponder 130. Alternatively or additionally, other electronic components of the RFID transponder 130 can also have temperature-dependent properties that can be detected in order to determine the temperature of the RFID transponder 130 and thus of the rotor 110 based on these detected properties.

[0053] In an alternative embodiment not shown, the temperature sensor 134 can also be arranged outside the RFID transponder 130. The temperature sensor 134 can, for example, be arranged at a position where the temperature at the rotor 110 of the turbomolecular pump 100 is expected to be more than 85°C during operation. In such a case, the electronics of the RFID transponder 130 should be arranged at a position on the rotor 110 where the temperature is always less than 85°C.

[0054] The electronics of the RFID reader 140 are connected to the drive electronics or control electronics (not shown) of the turbomolecular pump 100 via signal lines (not shown) via vacuum feedthroughs of the turbomolecular pump 100. As explained above, the evaluation electronics for the measurement data of the temperature sensor 134 are integrated into the RFID reader 140 in the present embodiment. Alternatively, the evaluation electronics for the data that the RFID reader 140 receives from the RFID transponder 130 can also be integrated into the drive electronics of the turbomolecular pump 100 or into a separate module outside the turbomolecular pump 100.

[0055] Furthermore, the entire electronics of the RFID reader 140, i.e., not just the evaluation electronics, can be integrated into a controller of the turbomolecular pump 100 and thus be located remotely from the antenna of the RFID reader 140. In such a case, the antenna of the RFID reader 140 is connected to the electronics integrated into the controller of the turbomolecular pump 100 via a coaxial cable. However, the length of such a coaxial cable should be as short as possible, and cutting the shielding of such a coaxial cable to create a vacuum feedthrough can lead to energy losses.

[0056] Therefore, in the embodiment of Fig. 1 The electronics of the RFID reader 140 are arranged on a common circuit board with the antenna of the RFID reader 140 in the interior of the turbomolecular pump 100, i.e., within its vacuum region. A coaxial cable is therefore not required in this embodiment. The electronics of the RFID reader 140 are controlled via a digital interface, for example, 12C or SPI, and the required signal lines are connected to the controller of the turbomolecular pump 100 via a vacuum feedthrough.

[0057] For communication between the RFID transponder 130 and the RFID reader 140, their components, such as their resonant circuits, are adapted to the frequency for communication between the RFID transponder 130 and the RFID reader 140. The frequencies for such RFID communication are, for example, between 10 and 15 MHz. Alternatively, a frequency range between 800 and 900 MHz or between 2 and 5 GHz (as a UHF system) can be used, for example, for using the RFID transponder 130 at high temperatures.

[0058] During operation of the turbomolecular pump 100, the RFID reader 140 supplies the RFID transponder 130 with the integrated temperature sensor 134 with energy at predefined time intervals, for example, at a short predefined time interval every second. Within such a time interval, one or more respective measured values ​​of the temperature sensor 134, i.e., measured values ​​of the temperature of the rotor 110, are transmitted from the RFID transponder 130 to the RFID reader 140 using the load modulation described above and evaluated by the integrated electronics of the RFID reader 140.

[0059] Fig. 2 shows two perspective views of the section of the vacuum pump or turbomolecular pump 100 according to the invention, which is shown as a sectional view in Fig. 1 and includes the area of ​​the labyrinth seal 116. Fig. 2A shows a bottom view of the rotor disc 114 and the labyrinth hub 122, while Fig. 2B a top view of the rotor disc 114 and the labyrinth hub 122.

[0060] As can be seen, the circuit board 300 of the RFID transponder 130 (see also Fig. 3 ) and the circuit board of the RFID reader 140 are designed in a ring shape such that each circuit board encloses the rotor shaft 112. The two circuit boards of the RFID transponder 130 and the RFID reader 140 enclose the rotor shaft 112 within the labyrinth seal 116 such that the distance between the respective circuit boards relative to the rotational axis of the rotor shaft 112 is minimized. This minimizes the centrifugal forces exerted on the components or elements of the RFID transponder 130 during operation of the turbomolecular pump 100 when the RFID transponder 130 rotates together with the rotor 110 of the turbomolecular pump 100.

[0061] The elements or components on the circuit board 300 of the RFID transponder 130, together with the screw connection 132, can cause additional imbalance of the rotor 110. To minimize such additional imbalance, the elements or components of the RFID transponder 130, including the screw connection 132, are distributed over the circumference of the circuit board of the RFID transponder 130 in such a way that a sum vector of individual imbalances of the components and the antenna of the RFID transponder 130, including the screw connection 132, is minimized in magnitude and ideally is the zero vector. In other words, the components or parts of the RFID transponder 130, including the antenna and the screw connection 132, are to be arranged or distributed over the circumference of the circuit board 300 of the RFID transponder 130 in such a way that the individual imbalances of these components or parts compensate each other.

[0062] Fig. 3 shows a top view of a respective embodiment of the circuit board 300 of the RFID transponder 130 (cf. Fig. 1 and 2 ) with a respective embodiment of the antenna 310. Fig. 3A shows a first embodiment of the antenna 310, in which individual turns of a conductor track 320 run concentrically and circularly on the circuit board 300. Starting with an outer turn, the diameter of the conductor track 320 decreases with each revolution around the circular circuit board 300 until the innermost turn. Fig. 3B shows a second embodiment of the antenna 310 with a half-shell-shaped arrangement of conductor tracks 320.

[0063] By means of the concentric arrangement of the conductor track 320 of Fig. 3A a larger shape of the antenna 310 can be achieved compared to the half-shell arrangement of the conductor track 320 of Fig. 3B The maximum of the electromagnetic field emitted by the antenna 310 is in the first embodiment of Fig. 3A but in the center of the antenna, ie in the area of ​​the axis of rotation of the rotor shaft 112 (cf. Fig. 1 and 2 ). In the half-shell shape of the conductor track 320 of Fig. 3B the electromagnetic field is created coaxially around the rotor shaft 112. This makes the second embodiment of Fig. 3B less susceptible to interference in RFID communication between the RFID transponder 130 and the RFID reader 140.

[0064] Fig. 4 shows an alternative embodiment for the arrangement of the RFID transponder 130 on the rotor 110 of the turbomolecular pump 100 and the RFID reader 140 on the stator 120 of the turbomolecular pump 100, specifically in the region of a magnetic bearing 400. The magnetic bearing 400 is designed as a permanent bearing and comprises two stacks of permanent magnets 410, one of which is arranged on the rotor shaft 112 and another on a journal of a high-vacuum star 420 of the stator 120.

[0065] The RFID transponder 130 is in turn designed as a circuit board into which the components of the RFID transponder 130 are embedded. Furthermore, the RFID transponder 130 or its circuit board is arranged concentrically to the axis of rotation of the rotor shaft 112, so that the axis of rotation of the rotor shaft 112 represents a central axis or axis of symmetry for the RFID transponder 130. This also applies to the RFID reader 140, whose components are consequently also embedded in a circuit board and which is also arranged symmetrically to the axis of rotation of the rotor shaft 112. The axis of rotation of the rotor shaft 112 thus forms a common central axis or axis of symmetry for both the RFID transponder and the RFID reader 140.

[0066] In addition, the above statements regarding the features of the circuit boards of the RFID transponder 130 and the RFID reader 140 also apply mutatis mutandis to the embodiment of Fig. 4 . The features include, among others, the possibly required shielding of the RFID transponder 130, its reinforcement using a potting compound, the cabling including a vacuum feedthrough for the RFID reader 140, the two embodiments of the antennas, which are shown in Fig. 3 are shown, and the cyclic energy and data transmission between the RFID transponder 130 and the RFID reader 140.

[0067] Fig. 5 shows a further embodiment of the vacuum pump or turbomolecular pump 100 according to the invention, in which an RFID communication between the RFID transponder 130 and the RFID reader 140 is provided in a different area of ​​the rotor shaft 112 than in the embodiments of Fig. 1 bis 4 . In the embodiment of Fig. 5 The RFID transponder and the RFID reader are arranged in an area of ​​a drive motor of the vacuum pump, ie in the axial direction along the rotor shaft 112 in an axial area of ​​a Holweck pump stage 500 of the vacuum pump 100 and beyond or below a projection 510 of the rotor shaft 112. In detail, the RFID transponder and the RFID reader are arranged either in an area of ​​drive magnets 520 of the rotor shaft 112 or in an area of ​​a balancing ring 530 of the rotor shaft 112.

[0068] For the sake of clarity, the RFID transponder 130 and the RFID reader 140 are Fig. 5 not explicitly shown. However, their arrangement is basically the same as in Fig. 4 shown arrangement, except that the RFID transponder 130 and the RFID reader 140 are not mounted on radially extending surfaces as in Fig. 4 , but are arranged on axially extending surfaces of the rotor shaft 112 or a corresponding element of a stator (not shown) of the drive motor. Otherwise, the above statements regarding the RFID transponder 130 and the RFID reader 140 also apply analogously to the embodiment of Fig. 5 .

[0069] In addition to the temperature sensor 134 (see Fig. 1 ), the RFID transponder 130 can include additional sensors or be communicatively connected to such sensors on the rotor shaft 112. Examples of such sensors are gyroscopes or strain gauges.

[0070] Furthermore, the combination of RFID transponder 130 and RFID reader 140 can be used to determine a coating thickness, for example, on the rotor shaft 112, if deposits are expected on components of the turbomolecular pump 100 due to the vacuum process or the use of the turbomolecular pump 100. This can be caused, for example, by reactive gases conveyed by the turbomolecular pump 100. Above a predetermined coating thickness or limit thickness, such deposits impair the operation of the turbomolecular pump 100.

[0071] The power radiated by the RFID reader 140, which is necessary for RFID communication, represents a measure of the coating of the antennas of the RFID transponder 130 and the RFID reader 140 with metals or semiconductor materials. The coating thickness due to deposits in the turbomolecular pump 100, e.g., on the rotor shaft 112, can be estimated by recording the power radiated by the RFID reader 140 as a function of time, e.g., at regular time intervals.

[0072] In other words, the power of the RFID reader 140 required to establish RFID communication provides information about the existing layer thickness of deposits on the antennas of the RFID transponder 130 and the RFID reader 140 and thus on the rotor shaft 112. Alternatively, only the change in the layer thickness of the deposits can be detected and monitored based on the change in the power required for RFID communication at predetermined time intervals. Bezugszeichenliste

[0073] 100Vacuum pump or turbomolecular pump 110Rotor 112Rotor shaft 114Rotor disk in the area of ​​a labyrinth seal 116Labyrinth seal 120Stator 122Labyrinth hub 130RFID transponder 132Screw connection 134Temperature sensor 140RFID reader 300RFID transponder circuit board 310RFID transponder antenna 320Antenna conductor track 400Magnetic bearing 410Permanent magnet 420High vacuum star 500Holweck pump stage 510Rotor shaft projection 520Drive magnet 530Balancing ring

Claims

1. A vacuum pump (100), comprising: a sensor (134) arranged on a first component (110) of the vacuum pump (100) and configured to measure a physical property of the first component (110), an RFID transponder (130) attached to the first component (110) and in communicative connection with the sensor (134), and an RFID reader (140) attached to a second component (120) of the vacuum pump (100) at a distance relative to the RFID transponder (130) such that the RFID reader (140) and the RFID transponder (130) are in communicative connection.

2. Vacuum pump (100) according to claim 1, wherein the RFID transponder (130) and the RFID reader (140) are arranged adjacent to each other in an interior of the vacuum pump (100).

3. Vacuum pump (100) according to claim 1 or 2, wherein the sensor (134) is integrated into the RFID transponder (130).

4. Vacuum pump (100) according to claim 1 or 2, wherein the sensor (134) and the RFID transponder (130) are arranged at a distance from each other.

5. Vacuum pump (100) according to one of claims 1 to 4, wherein the RFID transponder (130) is designed as a printed circuit board (300) embedded in the first component (110).

6. Vacuum pump (100) according to one of claims 1 to 5, wherein a shield is arranged between the RFID transponder (130) and the first component (110).

7. Vacuum pump (100) according to one of claims 1 to 6, wherein the first component (110) comprises a rotating element of the vacuum pump (100) to which the RFID transponder (130) and the sensor (134) are attached, and the second component (120) comprises a non-rotating element of the vacuum pump (100) to which the RFID reader (140) is arranged.

8. Vacuum pump (100) according to claim 7, wherein the RFID transponder (130) has a reinforcement.

9. Vacuum pump (100) according to claim 7 or 8, wherein elements of the RFID transponder (130) and of the sensor (134) are arranged on the rotating element (110) in such a way that imbalances of the rotating element (110) compensate each other.

10. Vacuum pump (100) according to one of claims 7 to 9, wherein the RFID transponder (130) is inserted into the rotating element (110) by means of a screw connection.

11. Vacuum pump (100) according to one of claims 1 to 10, wherein the RFID reader (140) has integrated electronics.

12. Vacuum pump (100) according to one of claims 1 to 11, wherein at least one electronic component associated with the RFID reader (140) is integrated into a control unit of the vacuum pump (100).

13. Vacuum pump (100) according to one of claims 1 to 12, wherein the RFID transponder (130) and / or the RFID reader (140) are designed to transmit a measurement signal of the sensor (134) by means of load modulation from the RFID transponder (130) to the RFID reader (140).

14. Vacuum pump (100) according to claim 13, wherein the RFID reader (140) has a bandpass filter for subcarrier frequencies at which the RFID transponder (130) transmits the measurement signal of the sensor (134).

15. A method for measuring a physical property of a first component (110) in a vacuum pump (100) having a sensor (134) attached to the first component (110), the method comprising: an RFID reader (140) attached to a second component (120) of the vacuum pump (100) that is different from the first component (110) sending a signal to an RFID transponder (130) attached to the first component (110) and in communicative connection with the sensor (134), the signal of the RFID reader (140) being received by the RFID transponder (130) to supply power to the RFID transponder (130) and the sensor (134),at least one measured value of the physical property of the first component (110) is detected by means of the sensor (134) and transmitted from the sensor (134) to the RFID transponder (130), and the at least one measured value is transmitted from the RFID transponder (130) to the RFID reader (140) by means of load modulation in the RFID transponder (130) and / or in the RFID reader (140).

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