Probes for phase change detection
The detection of media phase transitions in the food industry through non-invasive microwave probes has solved the problems of high costs and sensor contamination in the prior art, and achieved rapid and reliable media phase transition detection, which is suitable for various media, including organic solvents.
Patent Information
- Application Number
- CN202111032211.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Priority Date
- 2020-09-11
- Filing Date
- 2021-09-03
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2041-09-03
AI Technical Summary
The prior art has problems of high cost, unnecessary product losses and sensor contamination when detecting phase transitions of media in the food industry, especially the inconvenient use of conductivity sensors in organic solvents and the optical sensors are complex and expensive.
A non-invasive microwave probe is designed to transmit and receive microwaves in the direction of the medium using microwave chips and antennas. Combined with a data processing unit, the phase change of the medium is detected by the changes in microwave frequency and parameters, and a non-conductive separator and conductive shield are formed. Resonator space, prevents microwave leakage and can be used in combination with other sensors.
It realizes fast, reliable and low-cost media phase transition detection, avoids sensor contamination and product adhesion, is suitable for various media, including organic solvents, and can optimize media identification and homogeneity monitoring.
Smart Images
Figure CN114166865B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a probe for detecting phase changes in a container. Background Art
[0002] Often, for cost reasons, further optimization of processes is desired in industry. Therefore, various processes with various process media are often used in a chronologically consecutive manner in the same system. Mainly in the food industry, but also in the chemical, petroleum and paper industries, the goal is therefore to detect differences in the media and activate the associated process steps and minimize unnecessary product losses.
[0003] In the food industry, it is therefore necessary to clean production lines at defined intervals. These cleaning processes result in phase transitions between cleaning medium and product, which must be detected quickly and reliably. In addition, product-to-product changes are common, where the respective purity or quality of the reaction products needs to be identified as quickly as possible. Currently, conductivity sensors (e.g., the applicant's CLS54) or turbidity sensors (e.g., the applicant's OUSAF12) are often used for this purpose.
[0004] Optical sensors can have problems due to window contamination and restrictions on cleaning liquids. The use of conductivity sensors often proves to be unnecessary and too expensive. In addition, these conductivity sensors are not suitable for organic solvents. In order to overcome the limitations in detecting certain media differences (color, conductivity), a combination of optical and conductivity sensors can be envisaged. However, this approach proves to be too complex and costly. Another disadvantage of these sensors is that they protrude into the pipe cross section. As a result, these sensors cannot be pigged and the product may adhere to the sensor surface. Summary of the invention
[0005] An object of the present invention is to provide a non-invasive sensor for detecting phase changes.
[0006] This object is achieved by a probe for detecting changes in a medium in a container, the probe comprising: a process connection, which is used to connect the probe to the container, wherein the process connection is part of a shell, in particular an integral part of the shell; the shell comprises at least one microwave chip, the at least one microwave chip is used to generate microwaves, the at least one microwave chip is connected to at least one antenna, wherein the antenna transmits and receives microwaves in the direction of the medium; an interface, which is used to connect the probe to a superordinate unit; and a data processing unit, which is designed to receive data, in particular measurement data, from the superordinate unit via the interface, and the data processing unit is designed to transmit data to the superordinate unit to activate the microwave chip and process signals depending on the received microwaves.
[0007] One embodiment provides that the frequency of these microwaves is 100 to 10000 MHz, in particular 500 to 3000 MHz.
[0008] One embodiment provides that the antenna is designed as a strip conductor on a printed circuit board in the housing.
[0009] One embodiment provides that the process connection to the housing interior comprises an electrically conductive material and that the housing interior comprises an electrically conductive shield and forms a resonator space with a section of the container, in particular an electrically conductive section, wherein a diaphragm made of an electrically non-conductive material closes the probe head toward the medium.
[0010] One embodiment provides that the housing together with sections of the container, in particular the electrically conductive section, and the process connection are designed to prevent the emission of microwaves to the outside of the container.
[0011] One embodiment provides that the shield is designed as a layer on the printed circuit board.
[0012] One embodiment provides that the process connection is designed as a flange, a clamp connection, a sanitary coupling or an aseptic threaded connector, an SMS threaded connector, Varivent N or Neumo BioControl.
[0013] One embodiment provides that the probe head is designed for reflection measurement or transmission measurement and that the antenna is designed as a contact sensor or a free beam antenna.
[0014] One embodiment provides that the probe comprises at least one temperature sensor in the housing.
[0015] One embodiment provides that the data processing unit is designed to derive phase boundaries and phase changes from the signal which is dependent on the received microwaves.
[0016] One embodiment provides that the housing is designed to be hermetically sealed.
[0017] One embodiment provides that the interface is designed as an inductive interface and the probe can thereby be connected to a measuring transducer.
[0018] This results in a simple universal microwave probe for rapid detection of phase changes in media, especially foods, in various embodiments as a resonator or applicator variant. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] This is explained in more detail with reference to the following figures.
[0020] Figure 1 An embodiment of the claimed probe head (resonator design) is shown in cross-section;
[0021] Figure 2 An embodiment of the claimed probe (contact sensor) is shown;
[0022] Figure 3 An embodiment of the claimed probe (free beam) is shown;
[0023] Figure 4 An embodiment of the claimed probe head is shown in an overview view; and
[0024] Figure 5 The measurement results are shown.
[0025] In the drawings, like features are identified by like reference numerals. Specific embodiments
[0026] The claimed probe is indicated in its entirety by the reference numeral 1 and is Figure 1 Shown in.
[0027] A hermetically sealed probe 1 of hygienically designed is proposed, which detects phase boundaries of different liquid media in industrial processes by microwave technology. "Heat-tight" in this context is to be understood to mean that fluids such as the medium to be measured, air or dust cannot penetrate from the outside. Any electrical feedthroughs are also not included.
[0028] The probe 1 operates in the frequency range of 100 to 10000 MHz, but preferably in the range of 500 to 3000 MHz.The probe operates at at least one frequency.
[0029] In one embodiment, instead of using just one measuring frequency, switching occurs between several fixed frequencies, or the measuring frequency is continuously changed within a defined range. Thus, due to different penetration depths or available analyzable volume ranges, in addition to detecting phase boundaries of mutually exchanging media (see below), the homogeneity of the medium 12 to be measured can also be detected. In addition, these different frequencies can be used to optimize the recognition of different media.
[0030] In one exemplary embodiment, an additional measurement is performed in the short-wave range, wherein, in addition to the dielectric properties of the medium 12 , the electrical conductivity of the medium 12 is also detected.
[0031] By combining the probe 1 with another measuring method (e.g. another sensor), for example in the case where one of the conductivity sensors measures close to the probe surface, the two different signals can be correlated, thereby obtaining additional information about the homogeneity of the medium. For example, the distribution of fragments in a homogeneous medium, such as the distribution of pineapple slices in yogurt, can be monitored thereby. By varying the parameters of the microwaves, i.e. the frequency or the amplitude, the penetration depth into the medium can be influenced.
[0032] However, in a first non-invasive embodiment in contact with the medium, the probe 1 is equipped with a process connection 2, for example a clamp connection.
[0033] Therefore, the probe comprises a process connection 2 for connecting the probe 1 to a container 11, wherein the process connection 2 is part of a housing 5, in particular an integral part of the housing 5. The container 11 is, for example, a pipe, a pipe section, a beaker, etc. The housing 5 comprises at least one microwave chip 13 for generating microwaves, the at least one microwave chip 13 being connected to at least one antenna 3, wherein the antenna 3 transmits and receives microwaves in the direction of the medium 12. At the other end of the antenna 3, the probe 1 comprises an interface 14 for connecting the probe 1 to a superordinate unit 15, such as a measuring transducer. The probe 1 comprises a data processing unit 9, such as a microcontroller, which is designed to receive data, in particular measurement data, from the superordinate unit 15 via the interface 14, and the data processing unit is designed to transmit data to the superordinate unit 15 to activate the microwave chip 13 and process signals depending on the received microwaves. The data processing unit 9 can derive phase boundaries and phase changes based on the signals depending on the received microwaves.
[0034] The process connection 2 is made of a conductive material, such as a metal, or includes a conductive layer at least toward the inside of the housing. The process connection connects a shield 8, such as on a printed circuit board 7, located in the probe 1, to a metal conduit, and thereby forms a resonator space 10. The shield 8 is also a conductive layer. The space 10 is thus formed by the shield 8, the process connection 2 and partly by the container 11. The geometry and the material are adapted together with the medium 12 or the medium 12, 12' to be measured so that resonance is induced in the space 10.
[0035] On the dielectric side, the probe 1 is bounded by a diaphragm 4 made of a non-metallic material (e.g. PEEK). The diaphragm 4 is tightly connected to the process adapter and is located within the resonator space 10. In the interior of the housing in the resonator space 10 between the shield 8 and the diaphragm 4, the antenna 3 is mounted, for example, as a strip conductor, for example on a printed circuit board 7. In the interior of the resonator space 10 between the shield 8 and the diaphragm 4, the temperature sensor 6 is mounted, for example, to the printed circuit board 7. The antenna 3 and the temperature sensor 6 are electrically contacted with a data processing unit 9 (including a microwave chip 13) outside the resonator space 10, for example via plated through holes of the printed circuit board 7.
[0036] By introducing a second medium 12', which is different from the first medium 12, into the pipe and thereby into the resonator, the resonant frequency and the resonant bandwidth change due to the changed dielectric properties. The material-related measurement values associated with the resonance curve can be the width, the amplitude, the edge slope or the frequency shift. In one embodiment, this change is determined via the detection of the complex reflection parameter S11. To this end, the wave propagating to the measurement object and the return wave must be separated from each other by a component having directivity. In one embodiment, for example, the phase of the reflection parameter is determined. This is in Figure 5 The S11 parameters are shown in arbitrary units and are plotted over time.
[0037] Instead of or in addition to the analysis of the complex reflection factor S11, other scattering parameters S21, S12 and / or S22 can also be measured. Instead of or in addition to the measurement of the phase of the scattering factor, the amplitude of this scattering factor can also be measured.
[0038] The probe 1 comprises an inductive interface 14 for data and energy transmission. A cable 16 connects the probe 1 to a measuring transducer, i.e. a superordinate unit 15. Figure 4 The data is transmitted and received in digital form.
[0039] Instead of an inductive interface and a digital cable connection to a measuring transducer, the probe head 1 is in one embodiment a compact device comprising an integrated operating panel, display options and an analog power output.
[0040] Instead of an inductive interface and a digital cable connection to the measuring transducer, the probe head 1 comprises in one embodiment a fixed cable connection with digital transmission.
[0041] Instead of just one antenna 3 , a plurality of antennas can be provided, which differ in shape (antenna geometry) and thus allow measurements in different planes (scattered field applicator for near-field measurements, antenna applicator for far-field measurements).
[0042] The probe 1 may also be provided without a temperature sensor. In one embodiment, the temperature sensor 6 is located on one side of the resonator, for example, on a printed circuit board 7, see Figure 1 , which serves for temperature compensation of the medium 12. It is also conceivable, for example, to have a further temperature sensor on the side of the printed circuit board facing away from the process, which temperature sensor additionally serves for compensation of the ambient temperature.
[0043] Instead of being designed as a strip conductor, the antenna 3 and the temperature sensor 6 can also be soldered as wired components to the resonator side of the printed circuit board.
[0044] Instead of a clamp connection, any other process connection used in industry can also be envisaged in various diameters of the container 11, such as sanitary coupling threaded joints, aseptic threaded joints, ISO 2852 clamps, SMS threaded joints, Varivent N or Neumo BioControl, etc. In particular, the above-mentioned variants including the resonator space 10 are independent of the pipe diameter.
[0045] In one embodiment, the probe 1 is fixedly attached to the pipe section using a flange connection. In this sense, the probe 1 can be provided for different pipe diameters.
[0046] In one embodiment, the process connection 2 is a metallized, electrically conductive plastic process connection.
[0047] In one embodiment, the diaphragm 4 is made of a non-metal such as plastic, ceramic or glass.
[0048] replace Figure 1 While resonator measurements are shown, any other type of microwave measurement system is also contemplated.
[0049] Figure 2 Reflection measurements (left) and transmission measurements (right) are shown using an embodiment of an antenna 3 as a contact sensor 17 or two contact sensors 17 on a non-metallic pipe section 11 (using corresponding antennas 3, 3'). The transmitted wave is denoted by reference numeral 18 and the received wave by reference numeral 19.
[0050] Figure 3 Shown are reflection measurements (top) and transmission measurements (bottom) with a free antenna 3 or two free antennas 3, 3' at an open dielectric bundle 12. One possible application here is a filling process.
[0051] In certain branches of industry, so-called pigs are used for cleaning pipelines. Such cleaning pigs are made of plastic (with a dielectric constant of about 2 to 5) or metal / plastic and can thus be easily detected. These pigs can be detected by the probe 1 .
[0052] In order to optimize the energy requirement of the probe 1 , a discontinuous operating mode with maximum sequence, multi-tone or burst measurements is possible.
[0053] Reference numerals list
[0054] 1 Probe
[0055] 2 Process connections
[0056] 3 Antenna
[0057] 3' Antenna
[0058] 4 Diaphragm
[0059] 5 Housing
[0060] 6 Temperature Sensor
[0061] 7. Printed Circuit Board
[0062] 8 Shielding
[0063] 9 Data processing unit
[0064] 10 Resonator Space
[0065] 11. Container
[0066] 12 Medium
[0067] 12' Medium
[0068] 13 Microwave Chip
[0069] 14 Interface
[0070] 15 Parent Unit
[0071] 16 Cable
[0072] 17 Contact Sensor
[0073] 18 Transmitting Waves
[0074] 19 Receiving Wave
Claims
1. A probe (1) for detecting changes in a medium (12) in a container (11), the probe comprising: - an industrial process connection (2) for connecting the probe (1) to the container (11), wherein the industrial process connection (2) is part of the housing (5); - The housing (5) comprises - at least one microwave chip (13), the at least one microwave chip is used to generate microwaves, the at least one microwave chip is connected to - at least one antenna (3), wherein the antenna (3) transmits and receives the microwaves in the direction of the medium (12); - an interface (14) for connecting the probe (1) to a superordinate unit (15); and a data processing unit (9) designed to receive data from the superordinate unit (15) via the interface (14) and to transmit data to the superordinate unit (15) to activate the microwave chip (13) and to process signals dependent on the received microwaves, wherein the industrial process connection (2) to the interior of the housing comprises an electrically conductive material, and the interior of the housing comprises an electrically conductive shield and forms a resonator space (10) with a section of the container (11), The diaphragm (4) made of non-conductive material closes the probe (1) toward the medium (12). Therein, the antenna (3) is mounted inside the housing in the resonator space (10) between the shield (8) and the diaphragm (4).
2. The probe (1) according to claim 1, wherein: The industrial process connection (2) is an integral part of the housing (5).
3. The probe (1) according to claim 1, wherein: The data processing unit (9) is designed to receive measurement data from the superordinated unit (15) via the interface (14).
4. The probe (1) according to claim 1, in, The frequency of the microwave is 100 to 10000 MHz.
5. The probe (1) according to claim 1, in, The frequency of the microwave is 500 to 3000 MHz.
6. The probe (1) according to claim 1, in, The antenna (3) is designed as a strip conductor on a printed circuit board (7) in the housing (5).
7. The probe (1) according to claim 1, in, The interior of the housing and the conductive section of the container (11) form the resonator space (10).
8. The probe (1) according to claim 1, in, The shielding element (8) is designed as a layer on the printed circuit board (7).
9. The probe (1) according to claim 1, in, The industrial process connection (2) is designed as a flange, a clamp connection, a sanitary coupling or an aseptic threaded joint, an SMS threaded joint, Varivent N or Neumo BioControl.
10. The probe (1) according to any one of claims 1 to 5, in, The probe head is designed for reflection measurement or transmission measurement, and the antenna (3) is designed as a contact sensor or a free beam antenna.
11. The probe (1) according to any one of claims 1 to 5, in, The probe (1) comprises at least one temperature sensor (6) in the housing (5).
12. The probe (1) according to any one of claims 1 to 5, in, The data processing unit (9) is designed to derive phase boundaries and phase changes from the signal dependent on the received microwaves.
13. The probe (1) according to any one of claims 1 to 5, in, The housing (5) is designed to be hermetically sealed.
14. The probe (1) according to any one of claims 1 to 5, in, The interface (14) is designed as an inductive interface and the probe (1) can thereby be connected to a measuring transducer.