Measuring assembly

Abstract

The invention relates to a measurement assembly (1, 101) for determining a property of a multiphase flowable medium, comprising: - a measuring tube (2, 102) for carrying the medium, the measuring tube (2, 102) having a first antenna receptacle (3, 103), - a first microwave antenna (5, 105), which is arranged in the first antenna receptacle (3, 103), - a first separating disc (7, 107) for separating the first microwave antenna (5, 105) from the medium, the first separating disc (7, 107) being arranged in the first antenna receptacle (3, 103), and the first microwave antenna (5, 105) being arranged behind the first separating disc (7, 107) in the radial direction, - a measurement circuit (9), the measurement circuit (9) having a high-frequency generator for supplying the first microwave antenna (5, 105) with an excitation signal, in particular with a sequence of high-frequency signals, and the measurement circuit (9) being configured to determine the property of the medium on the basis of a received measurement signal.

Description

[0001] Measuring arrangement

[0002] The invention relates to a measuring arrangement for determining a property of a multiphase, flowable medium.

[0003] Using microwaves, the physical quantities permittivity and loss factor of a medium in a process line can be determined. From these two quantities

[0004] - measured either at one or across many different frequencies - conclusions can be drawn about application-specific parameters, for example the proportion of water in a mixture of water and other non-polar or slightly polar components or a solid content in a liquid medium.

[0005] The established transmission-Z-reflection measurement is described in LF Chen, CK Ong, CP Neo, VV Varadan, VK Varadan - “Microwave Electronics, Measurement and Materials Characterization”, John Wiley & Sons Ltd., 2004. For this purpose, the microwave signal is coupled to the medium in a container or measuring tube at two different positions, the scattering parameters (transmission and, if applicable, reflection) between these coupling structures are measured, and the measured scattering parameters are used to calculate the physical properties of the medium.

[0006] WO 2018 / 121927 A1 teaches a measuring arrangement for analyzing the properties of a flowing medium using microwaves. In addition to the microwave antennas, the measuring arrangement has an electrically insulating lining layer on the inner surface of the measuring tube. This lining layer forms a dielectric waveguide through which a microwave signal can be transmitted, at least in part, from a first microwave antenna to a second microwave antenna. One application for such a measuring arrangement is the determination of solids content in the liquid medium being conveyed. WO 2021 / 099152 A1 teaches a microwave antenna having a front section in contact with the medium, through which the excitation signal is emitted into the medium. A disadvantage of the disclosed solutions is that, in the disclosed form, they are not suitable for hygiene applications.

[0007] The invention is based on the object of remedying the problem.

[0008] The problem is solved by the measuring arrangement according to claim 1.

[0009] The measuring arrangement according to the invention for determining a property of a multi-phase, flowable medium comprises:

[0010] - a preferably metallic measuring tube for guiding the medium, wherein the measuring tube has a first antenna receptacle, - a first microwave antenna which is arranged in the first antenna receptacle,

[0011] - a first separating disc for separating the first microwave antenna from the medium, wherein the first separating disc is arranged in the first antenna receptacle, wherein the first microwave antenna is arranged radially behind the first separating disc,

[0012] - a measuring circuit, wherein the measuring circuit has a high-frequency generator for feeding the first microwave antenna with an excitation signal, in particular with a sequence of high-frequency signals, wherein the measuring circuit is configured to determine the property of the medium on the basis of a received measuring signal.

[0013] The advantage of the measuring arrangement according to the invention is that measuring arrangements for wastewater or pulp and paper applications, in which the first microwave antenna is in direct contact with the medium, can be easily converted for hygienic applications. This is achieved by means of the first separating disk, which is arranged between the medium to be conveyed and the first microwave antenna and thus prevents the first microwave antenna from coming into contact with the medium. The first separating disk can be designed in such a way that it meets the application-specific hygiene requirements. For this purpose, a special material with which the medium can come into contact or a special geometry in which undercuts are avoided can be provided. Another advantage is that with a suitable choice of material and geometry of the first separating disk, improved irradiation of the excitation signal into the medium is achieved.

[0014] In the context of the invention, the separating disk is to be understood as a disk. A disk is a geometric body which, at least in sections, assumes the shape of a cylinder and whose disk radius is, at least in sections, many times greater than its thickness. The separating disk cannot therefore be understood as part of a liner applied to the inside of the measuring tube as defined in WO 2018 / 121927 A1, as a waveguide as defined in US Pat. No. 4,755,743, as part of an electrically insulating measuring tube body as defined in US Pat. No. 3,999,443, or as an electrically insulating sheath as defined in WO 00 / 43759 A1.

[0015] The high-frequency generator is preferably configured to generate an excitation signal covering a frequency range from 100 MHz to 100 GHz, in particular from 500 MHz to 50 GHz, and preferably from 800 MHz to 15 GHz. The first microwave antenna is configured to radiate the provided excitation signal into the interior of the measuring tube or into the medium. The excitation signal is a microwave signal that is essentially free from the influences of the medium in the measuring tube. The first microwave antenna can also detect the reflected, back-propagating measurement signal. The measurement signal is also a microwave signal that essentially comprises the excitation signal with a component resulting from the interaction of the excitation signal with the medium.The measuring circuit comprises a microcontroller, logic switching elements and / or electrical components and is designed to determine a property of the medium depending on the proportion.

[0016] Advantageous embodiments of the invention are the subject of the subclaims.

[0017] One embodiment provides that the first cutting disc comprises a material which is listed in the following list:

[0018] - Polyetheretherketones (PEEK)

[0019] - Polytetrafluoroethylene (PTFE)

[0020] - Perfluoroalkoxy (PFA)

[0021] - Glass

[0022] - Ceramics

[0023] With regard to hygienic design, the material must meet the applicable standards and guidelines for food contact required for the application. Such as applicable sections of the US FDA (2022). The material preferably meets the requirements of the FDA (2022), EHEDG, in particular EN 1672-2 and / or DIN EN ISO 14159:2008-07, 3-A Sanitary Standards, (EC) No. 1935 / 2004, (EU) No. 10 / 2011, GB 4806.1-2016, GB 4806.7-2016, and / or GB 4806.11-2016.

[0024] One embodiment provides that the first separating disc has a first separating disc receptacle in which the first microwave antenna is arranged, in particular in a materially bonded manner.

[0025] The advantage of a material-to-material connection between the first microwave antenna and the first cutting disc holder or the first cutting disc is the improved coupling of the generated excitation signal into the cutting disc.

[0026] One embodiment provides that the first cutting disc has a first cutting disc section with a first cutting disc thickness d l t wherein the first cutting disc has a second cutting disc section with a second cutting disc thickness d2, wherein the first cutting disc thickness d ± is smaller than the second separating disc thickness d2, wherein the first separating disc section forms a smallest separation between the medium and the first microwave antenna.

[0027] It is advantageous if the distance between the first microwave antenna and the medium is as small as possible. The first separating disc has multiple separating disc thicknesses to improve the connection between the first microwave antenna and the first separating disc itself and to ensure the best possible mechanical stability of the first separating disc. This allows the first separating disc section, through which the excitation signal propagates, to be designed as thin as possible. For the second separating disc section—through which a much smaller proportion of the excitation signal propagates—a comparatively thick separating disc can be provided to improve the mechanical stability of the first separating disc.

[0028] One design provides that the first cutting disc thickness d ± a maximum of 1 millimeter, in particular a maximum of 1.5 millimeters and preferably a maximum of 2 millimeters.

[0029] It has been found that the portion of the excitation signal radiated into the medium that is usable for measurements (the reflection factor is below -6 dB, ie at least 75% of the power is radiated) decreases with increasing thickness of the cutting disc. For the claimed measuring arrangement, it was demonstrated that with a cutting disc thickness d ± of 1 millimeter approximately 90% of the useful band (1.8-3 GHz), with a cutting disc thickness d ± of 2 millimeters only about 75% of the usable band and with a cutting disc thickness d ± At a pitch of 3 millimeters, only approximately 50% of the usable band lies below -6 dB. This means that in the latter case, only half of the usable band contributes to determining the properties of the multiphase, flowable medium.

[0030] One embodiment provides that the measuring tube has a measuring tube collar extending around a circumference of the first antenna receptacle.

[0031] The measuring tube collar has the advantage that it increases the mechanical stability of the first antenna holder and thus also the robustness of the entire measuring arrangement, in particular the module comprising the first microwave antenna, the first separating disk and any other components.

[0032] One embodiment provides that the measuring tube has a first measuring tube section with a first outer diameter D l t wherein the measuring tube has a second measuring tube section with a second outer diameter D2, wherein the first outer diameter D1 is larger than the second outer diameter D2, wherein the first antenna receptacle is located in the first measuring tube section.

[0033] One embodiment provides that the measuring tube has a measuring section in which the first microwave antenna is arranged, wherein the measuring tube is spherically shaped in the measuring section.

[0034] The advantage of this design is that it allows for a circular first antenna mount in the measuring tube for a separating disc that is at least partially cylindrical, without creating undercuts between the measuring tube and the first separating disc in which solids from the medium could accumulate. By arranging the first separating discs flush with the front of the measuring tube, no steps form in the medium-carrying measuring tube channel, thus preventing turbulence in the medium.

[0035] A design includes:

[0036] - a first disc holder for fixing the first separating disc in the first antenna receptacle, wherein the first disc holder is designed and arranged on the measuring tube such that the first separating disc is clamped in the first antenna receptacle.

[0037] One embodiment provides that the first separating disc has, in a front section, a sealing agent receptacle running along the circumference, in particular in the form of an indentation, with a sealing agent arranged therein.

[0038] The sealant can be a sealant that is in a solid state during assembly (e.g. an O-ring) or a sealant that is initially applied in liquid form and then hardened.

[0039] One embodiment provides that the first microwave antenna has a metallic carrier body with a carrier body receptacle, wherein the first microwave antenna has a ceramic with a metallization which is arranged in the carrier body receptacle, wherein the first microwave antenna has an opening which extends through the carrier body and the ceramic, wherein the first microwave antenna comprises a coaxial plug which is arranged in the opening.

[0040] An advantage of this design is the high compactness of the first microwave antenna with high pressure and temperature resistance. Such a first microwave antenna is known from WO 2021 / 099152 A1, which is incorporated herein by reference.

[0041] A design includes:

[0042] - a first disc fastening which is configured to fix the first separating disc to the disc holder and / or the first microwave antenna and to shield the first microwave antenna.

[0043] The first pane mount rests on the rear side of the first microwave antenna. This reduces signal loss of the excitation signal by preventing a portion of the excitation signal from being emitted via the rear side. It is also advantageous if the first pane mount additionally or alternatively covers or shields a lateral surface of the first microwave antenna.

[0044] One embodiment provides that the first pane fastening and the first pane holder are designed and arranged around the first microwave antenna in such a way that a ground connection to the metallization (ie a connection to ground via the metallization) is realized.

[0045] The metallization of the disc holder prevents the microwave signal (excitation signal) from radiating into the electronics chamber instead of into the medium.

[0046] A design includes:

[0047] - a second microwave antenna, in particular identical in construction to the first microwave antenna, wherein the measuring tube has a second antenna receptacle, in particular oriented diametrically to the first antenna receptacle, wherein the second microwave antenna is arranged in the second antenna receptacle,

[0048] - a second separating disk for separating the second microwave antenna from the medium, wherein the second separating disk is arranged in the second antenna receptacle, wherein the second microwave antenna is arranged radially behind the second separating disk, wherein the second microwave antenna is configured to receive the measurement signal.

[0049] A design includes:

[0050] - a second disc holder for fixing the second separating disc in the second antenna receptacle, wherein the second disc holder is designed and arranged on the measuring tube such that the second separating disc is clamped in the second antenna receptacle.

[0051] One embodiment provides that the measuring tube has a measuring tube interior, wherein the first disc holder is connected to the second disc holder via at least one fastening means, wherein the first disc holder and the second disc holder are arranged on the measuring tube and connected to each other in such a way that they cause a force in the direction of the measuring tube interior on the respective disc holder.

[0052] The invention is explained in more detail with reference to the following figures. They show:

[0053] Fig. 1: an exploded view of a module of a first embodiment of the measuring arrangement according to the invention;

[0054] Fig. 2: an exploded view of the entire first embodiment of the measuring arrangement according to the invention;

[0055] Fig. 3: a cross-section through the first embodiment of the measuring arrangement;

[0056] Fig. 4: an exploded view of a module of a second embodiment of the measuring arrangement according to the invention;

[0057] Fig. 5: a cross-section through the second embodiment of the measuring arrangement; and

[0058] Fig. 6: a perspective and partially sectioned view of the measuring arrangement according to the invention. Fig. 1 shows an exploded view of a module of a first embodiment of the measuring arrangement 1 according to the invention. The module shown comprises a first separating disk 7, which is configured to separate the first microwave antenna 5 from the flowable medium. The first separating disk 7 is intended to prevent the first microwave antenna 5 from coming into contact with the flowing medium. The first separating disk 7 is designed such that it meets the requirements of FDA, (EC) No. 1935 / 2004, GB 4806.1-2016, GB 4806.7-2016 and / or GB 4806.11-2016. Furthermore, the first separating disk 7 has a first separating disk holder 10, which can be designed as a recess. For this purpose, it preferably has PEEK, PTFE, PFA, glass or ceramic as the material, or is formed therefrom.The first separating disk holder 10 is designed such that a first microwave antenna 5 can be arranged therein, at least in sections. For sufficient fastening, a material-to-material fastening of the first microwave antenna 5 in the first separating disk holder 10 can be provided. The first microwave antenna 5 is designed to emit an excitation signal into the medium. Furthermore, the first microwave antenna 5 has a metallization on an outer surface. The module further comprises a first disk holder 21, which is designed to fasten the first separating disk 7 to a measuring tube. For this purpose, the first disk holder 21 is designed and can be arranged on the measuring tube such that the first separating disk 7 is clamped in the first antenna holder (not shown) provided in the measuring tube. The first disk holder 21 has an opening through which the first microwave antenna 5 can be arranged orthrough which the first microwave antenna 5 extends in the assembled state. The first microwave antenna 5 is fastened to the first separating pane 7 and the first pane holder 21 by a first pane fastening 28. The first pane fastening 28 not only serves to fasten the first microwave antenna 5, but must also be designed and arranged such that it shields the first microwave antenna 5 in the radial direction. For this purpose, the first pane fastening 28 and the pane holder 21 are designed and arranged around the first microwave antenna 5 in such a way that a ground connection to the metallization of the first microwave antenna 5 is realized. The first pane fastening 28 is mechanically connected to the first pane holder 21 and the first separating pane 7 by means of at least one fastening means 19 (e.g. screws or rivets).

[0059] When using two microwave antennas, it is advantageous to use two identically constructed microwave antennas. In this case, one of the two microwave antennas is configured to transmit the excitation signal, and the other microwave antenna is configured to receive a measurement signal. Accordingly, the module then comprises a second cutting disc 8 with a second cutting disc holder 11, a second microwave antenna 6, a second disc holder 22, and a second disc mount 29.

[0060] Fig. 2 shows an exploded view of the entire first embodiment of the measuring arrangement 1 according to the invention. The measuring arrangement 1 shown comprises two of the modules shown in Fig. 1 in an assembled state. These can be arranged diametrically on a measuring tube 2 with a first antenna receptacle 3 and a second antenna receptacle 4. For sufficient sealing, a sealing means 25 is provided in each case, which can be arranged in a front-end sealing means receptacle 24 of the separating disks 7, 8. The sealing means 25 can be a sealing ring, as shown. The measuring tube 2 has a connecting device in the form of a flange on each end face. The measuring tube 2 is spherical in the area of ​​the antenna receptacles 3, 4. The two modules can be mechanically connected to one another via fastening means 27 in such a way that they are tensioned against one another, thus exerting a mutual force on the modules in the direction of the measuring tube interior 26.

[0061] Fig. 3 shows a cross section through the first embodiment of the measuring arrangement 1. The assembled module shown in Fig. 1 is arranged in the first antenna receptacle 3 of the measuring tube 2. The first separating disc 7 has a first separating disc section 12 in which the first separating disc 7 has a first separating disc thickness d ± and a second cutting disc section 13, in which the first cutting disc 7 has a second cutting disc thickness d2. The first cutting disc thickness d ± smaller than the second separation disc thickness d2. The first separation disc section 12 forms a minimum separation between the medium inside the measuring tube and the first microwave antenna 5. For this purpose, the first separation disc thickness d ±a maximum of 3 millimeters, in particular a maximum of 2 millimeters, and preferably a maximum of 1 millimeter. The design of the different separating disc thicknesses forms a first antenna receptacle 3 in which the first microwave antenna 5 is arranged. The first microwave antenna 5 can be firmly bonded to the first separating disc 7 by means of an adhesive. For this purpose, an adhesive gap (approximately 0.2 mm) can be provided between the end face of the first microwave antenna and the opposite surface of the first antenna receptacle, which gap is filled with an adhesive.

[0062] Furthermore, the first separating disk 7 has a sealing means receptacle 24 in which a sealing means 25 in the form of a sealing ring is arranged. The sealing means receptacle 24 is designed and the sealing means 25 is configured and arranged in the sealing means receptacle 24 in such a way that it is in contact with the medium at least in sections and no cavities are formed. The sealing means 25 is made of a material suitable for hygienic applications. A metallic first disk holder 21 is arranged radially behind the first separating disk 7 and exerts a force on the first separating disk 7 in the direction of the measuring tube interior. The first disk holder 21 can interact with a second disk holder 22 of a second module that is arranged diametrically opposite.A first disk attachment 28 is arranged radially behind the first separating disk 7 and the first disk holder 21 and is configured to connect the first separating disk 7 to the first disk holder 21. In addition, the first disk holder 21 is configured such that it covers as large a rear surface of the first microwave antenna 5 as possible and establishes a connection between the metallization of the first microwave antenna 5 and the metallic first disk holder 21.

[0063] The first microwave antenna 5 comprises a metallized carrier body 30 with a carrier body receptacle 31 in which a ceramic 32 is arranged. The ceramic 32 has a through-opening 33 through which a coaxial connector 34 is inserted. The coaxial connector 34 is connected to the measuring circuit, which has a high-frequency generator for feeding the first microwave antenna 5 with an excitation signal. Alternatively, the coaxial connector 34 can be configured to forward an incoming measurement signal to the measuring circuit.

[0064] The measuring tube 2 has a measuring tube collar 15 extending around the circumference of the first antenna receptacle 3, in which the entire module is arranged. The measuring tube collar 15 facilitates installation and ensures a stable arrangement of the module on the measuring tube.

[0065] When using two identical microwave antennas or modules, the measuring arrangement 1 has two of the arrangements shown.

[0066] Fig. 4 shows an exploded view of a module of a second embodiment of the measuring arrangement 101 according to the invention. The module comprises a first separating disk 107, which tapers conically at the front. A sealing means 125 in the form of a sealing sleeve, which is to be arranged at the front of the first separating disk 107, also tapers conically at the front. The sealing means 125 has a first sealing means section in which it is cylindrical and has a substantially constant first sealing means diameter. Furthermore, the sealing means 125 has a second sealing means section with a second sealing means diameter, which is always smaller than the first sealing means diameter and decreases or increases in the longitudinal direction. The first separating disk 107 can be connected to a measuring tube via a first disk holder 121. The first disk holder 121 has a thread for this purpose.A resilient element 114 is arranged between the first separating disk 107 and the first disk holder 121. In the illustrated embodiment, the resilient element 114 consists of a cylindrical leaf spring. The four individual components mentioned – the sealing means 125, the first separating disk 107, the resilient element 114, and the first disk holder 121 – can be assembled together and secured in a receptacle in the measuring tube. A first microwave antenna 105 can then be guided through the first disk holder 121 and the resilient element 114 and arranged in a first separating disk receptacle 110 provided in the first separating disk 107. A first disk attachment 128, which comprises two clamp-shaped disks, is provided to attach the first microwave antenna 105 in the first separating disk receptacle 110. Four attachment means 127 serve to fasten the module to the measuring tube.Furthermore, the first disc attachment 128 is designed and arranged radially behind the first microwave antenna 105 such that the largest possible rear surface of the first microwave antenna 5 is covered.

[0067] When using two microwave antennas, it is advantageous to use two identically constructed microwave antennas. In this case, one of the two microwave antennas is configured to transmit the excitation signal, and the other microwave antenna is configured to receive a measurement signal. Accordingly, the module then comprises a second separating disk 108 with a second separating disk holder 111, a second microwave antenna 106, a second disk holder 122, and a second disk mount 129.

[0068] Fig. 5 shows a cross-section through the second embodiment of the measuring arrangement 101. The measuring arrangement 101 has a measuring tube 102 that—unlike in Fig. 3—is not spherical. Instead, the medium-conducting path has a circular surface in a cross-section in the measuring section, which is shortened by two diametrically oriented circular segments. The measuring tube 102 shown is a milled part machined from a metallic block. However, the measuring tube 2 with the spherical measuring section from Fig. 2 would be suitable as an alternative measuring tube for the second embodiment.

[0069] The measuring tube 102 has a first antenna receptacle 103, which is formed from an opening in the measuring tube wall and a hollow cylindrical collar. A sealing means 125, a first separating disk 107, a resilient element 114, and a first disk holder 121 are arranged in the first antenna receptacle 103. These four components serve to ensure a medium-tight separation between the first microwave antenna 105 and the medium to be conveyed. The first microwave antenna 105 is arranged in a first separating disk receptacle 110 and extends through an opening in the resilient element 114 and an opening in the first disk holder 121. The first disk holder 121 has a thread and is connected to the measuring tube 102 or to the collar of the measuring tube 102 via a screw connection.The sealing means 125 and the first separating disk 107 are clamped between the first disk holder 121 and a projection of the first antenna receptacle 103. The resilient element 114 in the form of a disc spring absorbs the force generated by the first disk holder 121.

[0070] The first microwave antenna 105 is identical to the first microwave antenna 5 of Fig. 3 and accordingly also has a carrier body 130 with a carrier body receptacle 131 in which a ceramic 132 is arranged, which has an opening 133. A coaxial connector 134 is inserted through the opening 133 and is connected to the measuring circuit, in particular to the high-frequency generator. The first microwave antenna 105 is fastened in the first antenna receptacle 103 and the first separating disk receptacle 110 via a first disk fastening 128. The first microwave antenna 105 has a metallic outer surface. The first disk fastening 128 is metallic and at least partially conceals the rear side of the first microwave antenna 105.

[0071] When using two identical microwave antennas or modules, the measuring arrangement 101 has two of the arrangements shown.

[0072] Fig. 6 shows a perspective and partially sectioned view of the measuring arrangement 1 according to the invention. The measuring arrangement 1 comprises a measuring sensor which is configured to couple a received excitation signal into a medium to be examined and to measure a measurement signal which correlates with the property of the medium to be examined. Furthermore, the measuring arrangement 1 comprises a measuring transducer which is configured to provide an excitation signal, to evaluate the measured measurement signal and to determine the property to be determined. For this purpose, the measuring transducer has a measuring circuit 9 which has a high-frequency generator for feeding the first microwave antenna with an excitation signal, in particular with a sequence of high-frequency signals. Furthermore, the measuring circuit 9 is configured to determine the property of the medium based on a received measurement signal.For the determination, the measuring circuit 9 comprises a microprocessor, a memory, and logic circuit components. Furthermore, a computer program product containing the algorithm for determining the property of the medium can be stored in the measuring circuit 9.

[0073] The measuring arrangement 1 further comprises a measuring tube 2, in particular a metallic one, which has a first measuring tube section 16 with a first outer diameter D1 and a second measuring tube section 17 with a second outer diameter D2. The first outer diameter D1 is larger than the second outer diameter D2 and increases continuously in the longitudinal direction of the measuring tube, starting from the second outer diameter D2, until it reaches a maximum outer diameter. Thereafter, the first outer diameter D decreases. tagain. This causes the first measuring tube section 16 to widen. The first antenna receptacle 3 is arranged in the first measuring tube section 16. The measuring section 20 is part of the first measuring tube section 16. The first microwave antenna 5 is arranged in the measuring section 20. The measuring section 20 is spherical in the embodiment shown. A VARINLINE® housing from GEA, for example, is suitable as the measuring tube 2. This housing is designed to be free of dead spaces and is therefore ideal for hygienic applications. The measuring arrangement 1 also comprises a housing 35 which encloses the individual components of the module from Fig. 1 or the microwave antenna and protects them against external influences.

[0074] LIST OF REFERENCE SYMBOLS

[0075] Measuring arrangement 1 , 101

[0076] Measuring tube 2, 102 first antenna receptacle 3 second antenna receptacle 4 first microwave antenna 5, 105 second microwave antenna 6, 106 first separating disc 7, 107 second separating disc 8, 108 measuring circuit 9 first separating disc receptacle 10, 110 first separating disc section 12 second separating disc section 13 resilient element 114

[0077] Measuring tube collar 15 first measuring tube section 16 second measuring tube section 17

[0078] Fasteners 19

[0079] Measuring section 20 first disc holder 21 , 121 second disc holder 22, 122 front section 23

[0080] Sealant holder 24

[0081] Sealant 25, 125

[0082] Measuring tube interior 26

[0083] Fasteners 27, 127 First disc fastening 28, 128 Second disc fastening 29, 129 Support body 30, 130

[0084] Carrier body holder 31 , 131

[0085] Ceramics 32, 132

[0086] Opening 33, 133

[0087] Coaxial connectors 34, 134

[0088] Housing 35

Claims

PATENT CLAIMS 1. Measuring arrangement (1, 101) for determining a property of a multi-phase, flowable medium, comprising: - a measuring tube (2, 102) for guiding the medium, wherein the measuring tube (2, 102) has a first antenna receptacle (3, 103), - a first microwave antenna (5, 105) arranged in the first antenna receptacle (3, 103), - a first separating disc (7, 107) for separating the first microwave antenna (5, 105) from the medium, wherein the first separating disc (7, 107) is arranged in the first antenna receptacle (3, 103), wherein the first microwave antenna (5, 105) is arranged in the radial direction behind the first separating disc (7, 107), - a measuring circuit (9), wherein the measuring circuit (9) has a high-frequency generator for feeding the first microwave antenna (5, 105) with an excitation signal, in particular with a sequence of high-frequency signals, wherein the measuring circuit (9) is designed to determine the property of the medium on the basis of a received measuring signal.

2. Measuring arrangement according to claim 1, wherein the first separating disc (7, 107) comprises a material which is listed in the following list: - Polyetheretherketones (PEEK) - Polytetrafluoroethylene (PTFE) - Perfluoroalkoxy (PFA) - Glass - Ceramics 3. Measuring arrangement according to claim 1 or 2, wherein the first separating disc (7, 107) has a first separating disc receptacle (10, 110) in which the first microwave antenna (5, 105) is arranged, in particular in a materially bonded manner.

4. Measuring arrangement according to at least one of the preceding claims, wherein the first cutting disc (7, 107) has a first cutting disc section (12, 112) with a first cutting disc thickness d ± , wherein the first cutting disc (7, 107) has a second cutting disc section (13, 113) with a second cutting disc thickness d2, wherein the first cutting disc thickness d ± is smaller than the second separating disc thickness d2, wherein the first separating disc section (12, 112) forms a smallest separation between the medium and the first microwave antenna (5, 105).

5. Measuring arrangement according to at least one of the preceding claims, wherein the first cutting disc thickness d ± a maximum of 3 millimeters, in particular a maximum of 2 millimeters and preferably a maximum of 1 millimeter.

6. Measuring arrangement according to at least one of the preceding claims, wherein the measuring tube (2) has a measuring tube collar (15) extending around a circumference of the first antenna receptacle (3).

7. Measuring arrangement according to at least one of the preceding claims, wherein the measuring tube (2) has a first measuring tube section (16) with a first outer diameter D l t wherein the measuring tube (2) has a second measuring tube section (17) with a second outer diameter D2, wherein the first outer diameter D1 is larger than the second outer diameter D2, wherein the first antenna receptacle (3) is located in the first measuring tube section (16).

8. Measuring arrangement according to at least one of the preceding claims, wherein the measuring tube (2) has a measuring section (20) in which the first microwave antenna (5) is arranged, wherein the measuring tube (2) is spherically formed in the measuring section (20).

9. Measuring arrangement according to at least one of the preceding claims, comprising: - a first disc holder (21, 121) for fixing the first separating disc (7, 107) in the first antenna receptacle (3, 103), wherein the first disc holder (21, 121) is designed and arranged on the measuring tube (2, 102) in such a way that the first separating disc (7, 107) is clamped in the first antenna receptacle (3, 103).

10. Measuring arrangement according to at least one of the preceding claims, wherein the first separating disc (7) has in a front section (23) a sealing means receptacle (24) running around the circumference, in particular in the form of an indentation, with a sealing means (25) arranged therein.

11. Measuring arrangement according to at least one of the preceding claims, wherein the first microwave antenna (5, 105) has a metallic carrier body (30, 130) with a carrier body receptacle (31, 131), wherein the first microwave antenna (5, 105) has a ceramic (32, 132) with a metallization which is arranged in the carrier body receptacle (31, 131), wherein the first microwave antenna (5, 105) has an opening (33, 133) extending through the carrier body (30, 130) and the ceramic (32, 132), wherein the first microwave antenna (5, 105) comprises a coaxial connector (34, 134) arranged in the opening (33, 133).

12. Measuring arrangement according to at least one of the preceding claims, comprising: - a first disc fastening (28, 128) which is designed to fix the first separating disc (7) to the first disc holder (21) and / or the first microwave antenna (5, 105) and to shield the first microwave antenna (5, 105).

13. Measuring arrangement according to claim 11 and 12, wherein the first disc fastening (28, 128) and the disc holder (21, 121) are designed and arranged around the first microwave antenna (5, 105) in such a way that a connection to ground is realized via the metallization.

14. Measuring arrangement according to at least one of the preceding claims, comprising: - a second microwave antenna (6), in particular identical in construction to the first microwave antenna (5), wherein the measuring tube (2) has a second antenna receptacle (4), in particular diametrically oriented to the first antenna receptacle (3), wherein the second microwave antenna (6) is arranged in the second antenna receptacle (4), - a second separating disc (8) for separating the second microwave antenna (6) from the medium, wherein the second separating disc (8) is arranged in the second antenna receptacle (4), wherein the second microwave antenna (6) is arranged in the radial direction behind the second separating disc (8), wherein the second microwave antenna (6) is adapted to receive the measurement signal.

15. Measuring arrangement according to claim 14, comprising: - a second disc holder (22) for fixing the second separating disc (8) in the second antenna receptacle (4), wherein the second disc holder (22) is designed and arranged on the measuring tube (2) in such a way that the second separating disc (8) is clamped in the second antenna receptacle (4).

16. Measuring arrangement according to claim 15, wherein the measuring tube (2) has a measuring tube interior (26), wherein the first disc holder (21) is connected to the second disc holder (22) via at least one fastening means (27), wherein the first disc holder (21) and the second disc holder (22) are arranged on the measuring tube (2) and connected to one another in such a way that they cause a force in the direction of the measuring tube interior (26) on the respective disc holder (21, 22).

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