FIELD DEVICE OF AUTOMATION TECHNOLOGY

Description

[0001] The invention relates to a field device for automation technology, in particular a magnetic-inductive flow meter.

[0002] In automation technology, particularly in process automation, field devices are frequently used to detect and / or control process variables. Sensors, such as those integrated into level gauges, flow meters, pressure and temperature gauges, pH / ORP meters, conductivity meters, etc., are used to detect process variables, measuring levels, flow rates, pressure, temperature, pH, and conductivity. Actuators, such as valves or pumps, are used to control process variables, changing the flow rate of a liquid in a pipe section or the fill level in a container. In principle, all devices used close to the process that provide or process process-relevant information are considered field devices.In connection with the invention, field devices also include remote I / Os, radio adapters or, more generally, electronic measuring components that are arranged at the field level.

[0003] A field device is specifically selected from a group consisting of flow meters, level meters, pressure meters, temperature meters, limit level meters and / or analytical measuring instruments.

[0004] Flow meters include, in particular, Coriolis, ultrasonic, vortex, thermal and / or magnetic-inductive flow meters.

[0005] Level measuring devices include, in particular, radar-based level measuring devices, microwave level measuring devices, ultrasonic level measuring devices, time-domain reflectometric level measuring devices, radiometric level measuring devices, capacitive level measuring devices, inductive level measuring devices and / or temperature-sensitive level measuring devices.

[0006] Pressure measuring devices are, in particular, absolute, relative, or differential pressure devices.

[0007] Temperature measuring devices are, in particular, measuring devices with thermocouples and / or temperature-dependent resistors.

[0008] Level gauges include, in particular, vibronic level gauges, ultrasonic level gauges, and / or capacitive level gauges. Analytical instruments include, in particular, pH sensors, conductivity sensors, oxygen and active oxygen sensors, (spectro)photometric sensors, and / or ion-selective electrodes.

[0009] Furthermore, to reduce manufacturing costs, higher dimensional and form tolerances of the individual components are accepted. This leads to undesirable mechanical stresses being generated in individual components during assembly – resulting in malfunctions or defects – or to a failure to guarantee a tight seal between the respective components. Sealing connections are standardly used in field devices for automation technology to prevent the ingress of moisture or contaminants into the housing interior. These connections are designed according to operational requirements and generally require a compression force of at least 10% of the original size. However, the preload forces required for this are too high, especially for cold-formed components such as deep-drawn housing halves.These cannot withstand such preload forces, resulting in undesirable deformations, which means that local tightness cannot be guaranteed.

[0010] DE 10 2019 118711 A1 describes a field device of the prior art with a housing which is arranged on an outer surface of a measuring tube.

[0011] The invention is based on the objective of remedying the aforementioned problems. This objective is achieved by the field device of automation technology according to claim 1.

[0012] The field device for automation technology according to the invention comprises: a measuring tube for guiding a flowable medium, a measuring arrangement for determining a physical and / or chemical quantity of the medium, wherein the measuring arrangement is at least partially arranged on the measuring tube, a housing for accommodating at least one electronic component for operating the measuring arrangement, controlling a controlled variable of the measuring arrangement, determining a measured value of the measured quantity and / or evaluating the measured quantity, wherein the housing is arranged on an outer surface of the measuring tube and at least partially conceals the measuring arrangement, wherein the housing has a housing wall which, together with the outer surface of the measuring tube, defines a housing interior, wherein the housing wall has a first edge section which is in direct contact with the outer surface of the measuring tube at least partially, wherein the first edge section is bent away from the housing interior at least partially, and wherein at least the first edge section is clamped to the measuring tube in a force-fit manner.

[0013] Advantageous embodiments of the invention are the subject of the dependent claims.

[0014] According to the invention, the first edge section is provided to be free of any bending, wherein the first edge section has at least in a longitudinal section through the field device a first edge section longitudinal axis A which intersects the outer lateral surface of the measuring tube at an angle α, where α has an angular dimension between 1° and 10° or 5°.

[0015] The housing is mounted and attached to the measuring tube in such a way that the first edge section is deformed and at least in some sections a mechanical stress remains in the housing.

[0016] One embodiment provides that the housing comprises a first housing half, which is in particular cold-formed, and a second housing half, which is in particular cold-formed, wherein the first housing half and the second housing half are arranged diametrically and are fastened together.

[0017] One embodiment provides that the first housing mold half and the second housing mold half each have a second edge section, wherein the second edge sections are in direct contact with each other at least section by section, wherein the edge sections each have a second edge section longitudinal axis B in at least one cross-section through the field device, which intersects a median plane with an angle β, wherein the angle β has an angular measure of 1° to 10° or 5°, wherein the median plane is spanned by a longitudinal axis of the measuring tube and a transverse axis X perpendicular to it, wherein the median plane passes through at least one contact point of the second edge sections.

[0018] One embodiment provides that the first housing molded part half has at least one bending tab in the second edge section for forming a positive-locking connection with the second housing molded part half, wherein the at least one bending tab is bent over and is in effect with the second edge section of the second housing molded part half in contact.

[0019] It is particularly advantageous if at least one of the tabs is not bent over and is designed and configured to be connected to a grounding cable.

[0020] One embodiment provides that the second edge section of the first housing molded part half has a circumferential fold at least in sections to limit a displacement of the second housing molded part half in a longitudinal direction and / or a transverse direction of the measuring tube, wherein the fold engages in a recess in the second edge section of the second housing molded part half.

[0021] One embodiment provides that at least one bending tab is monolithically connected to the fold.

[0022] One embodiment provides that the housing has a groove on the inner housing surface to stiffen the housing wall, with a sealing agent being arranged in the groove at least in sections.

[0023] One embodiment provides that the measuring arrangement has a device for generating a magnetic field penetrating the measuring tube and at least two measuring electrodes for determining a measuring voltage induced in the medium, wherein the device for generating the magnetic field and the at least two measuring electrodes are arranged at least partially on the outer surface of the measuring tube. Fig. 1 : a perspective view of a field device according to the invention for automation technology; Fig. 2 : a cross-section through a first molded body half with an arranged electronic component; Fig. 3 : a longitudinal section through a magnetic-inductive flowmeter; Fig. 4 : a longitudinal section through a radar-based level gauge; Fig. 5 : a view from below of the first half of a molded body; Fig. 6 : a perspective view of a centering device; Fig. 7A : a perspective view of a partially cut-out housing with a first molded body half; Fig. 7B : a section of a cross-section through a housing with the first molded body half arranged and fixed; Fig. 8 : a section of an edge area of ​​a first housing molded part half in contact with a measuring tube; Fig. 9 : a section of an edge area of ​​a first housing molded part half in contact with a measuring tube; Fig. 10 : a section of an edge area of ​​a first housing mold half in contact with a second housing mold half; and Fig. 11 : a perspective view of a cutaway representation of a sealing seat between the first housing mold half and the second housing mold half.

[0024] Fig. 1 Figure 1 shows a perspective view of a field device for automation technology 1 according to the invention. The field device for automation technology 1 comprises a measuring tube 8 for guiding a flowable medium and a measuring arrangement, concealed by the shaped body 13, for determining a physical and / or chemical quantity of the medium, which is arranged on the measuring tube 8. The measuring arrangement can, for example, be a thermal sensor comprising two temperature probes or, in particular, two medium-contacting measuring electrodes for detecting a measuring voltage induced in a flowable medium in conjunction with a magnetic field-generating device. A multitude of other measuring arrangements are known, all of which are suitable for the field device for automation technology 1 according to the invention. Examples of these are the measuring arrangements of the measuring instruments mentioned in the introduction.Furthermore, the field device of automation technology 1 comprises a housing arranged on the measuring tube 8 for accommodating at least one electronic component 4 for operating the measuring arrangement, controlling a controlled variable of the measuring arrangement, determining a measured value of the measured variable and / or evaluating the measured variable of the measuring arrangement. The . Fig. 1 The housing is not shown in order to make visible the two-part molded body 13 arranged on the measuring tube 8, which, in the fully assembled state, is located in the housing and is wholly or at least partially concealed by it or by its housing wall. The molded body 13 serves to attach or hold the electronic component 4 and comprises a thermoplastic and / or an elastomer in at least a first section 21. The first section 21 is located on an outer surface of the molded body. In a more advantageous embodiment, the thermoplastic comprises expanded polypropylene, wherein the expanded polypropylene has a density ρ with 30 ≤ ρ ≤ 90 g / l and preferably 45 ≤ ρ ≤ 80 g / l. Expanded polypropylene with the density according to the invention exhibits reduced electrostatic charging of the molded body 13 during assembly of the molded body 13 in the housing or on the measuring tube. The molded body 13 is formed from a monolithic first molded body half 41 and an identical and also monolithic second molded body half 42. The first molded body half 41 is at least positively connected to the second molded body half 42. Together, the first molded body half 41 and the second molded body half 42 enclose the measuring tube 8 in at least one cross-section of the measuring tube.

[0025] The first section 21 is elastically designed and has a receptacle 19 for accommodating an electronic component 4. The receptacle 19 has at least one undercut 20. The receptacle 19 can be designed as a through opening or as a recess or blind hole. The undercut 20 can take the form of a locking lug 30 or more locking lugs and / or be designed as a guide rail 36 into which the electronic component 4 can be inserted or is inserted. The guide rail 36 is designed as an elongated slot in the molded body 13 or as a web projecting from a base body of the molded body 13. An electronic component 4 is arranged in the receptacle 19 in a form-fit and / or force-fit manner so that it is held and cannot fall out during assembly of the molded body 13 on the measuring tube 8 and / or on the housing. Additional C-parts for fastening can be provided, but are not necessary.The electronic component 4 is held by the first section 21, or by the undercut 20, in the form of four locking lugs 30 and a guide rail 36 integral to the molded body. Furthermore, the molded body 13 has a compression set, at least in the first section 21. DVR according to ISO 1798 from 0 ≤ DVR ≤ 20%, in particular 5 ≤ DVR ≤ 15% and preferably DVR < 15%. Since the molded body 13 is deformed at least section by section during assembly in the first section 21 in order to position and secure the electronic component 4 in the receptacle 19, it is essential that the compression set DVR of the molded body 13 is not greater than 20%. To keep mechanical stresses on the electronic component 4 as low as possible, it is further advantageous if the DVR greater than or equal to 5%. Furthermore, the molded body 13 exhibits, at least in the first section 21, an elongation at break according to ISO 1798 of 10 to 20%, and preferably of 14 to 16%. Alternatively, the necessary mechanical properties of the molded body 13 can also be described by its tensile strength. In this case, the molded body 13 exhibits, at least in the first section 21, a tensile strength according to ISO 1798 of 400 to 1300 kPa, in particular 600 to 1000 kPa, and preferably of 700 to 880 kPa.

[0026] The electronic component 4 comprises a printed circuit board 28 on which electronic components 37 are arranged for operating the measuring arrangement, controlling the controlled variable of the measuring arrangement, and / or evaluating the measured variable of the measuring arrangement. The electronic components 37 include, for example, processors, electromechanical components – such as switches or relays – as well as passive components such as resistors, capacitors, and / or inductive components, and / or active components such as diodes, transistors, and / or integrated circuits. In addition, a display 2 is arranged on a first section of the printed circuit board for displaying measured values ​​of the measured variable, process properties, and / or field device-specific system information. The electronic component 4 may also include connecting cables with which the coils are connected to the operating circuit. These cables may run in specially provided grooves and be secured there.

[0027] Fig. 2 shows a cross-section through the first half of the molded body 41 of the molded body Fig. 1 with arranged electronic component 4. The illustrated electronic component 4 comprises a printed circuit board (PCB) which has electronic components for operating the measuring arrangement, controlling the controlled variable of the measuring arrangement, and / or evaluating the measured variable of the measuring arrangement. The PCB has a rigid first PCB section 31 and a rigid second PCB section 32, which are separated from each other. The PCB also has a flexible third PCB section 33, which separates the first PCB section 31 from the second PCB section 32. The in Fig. 2 The housing (not shown) has an inner housing surface which, after assembly, is in mechanical contact with the illustrated first molded body half 41, at least partially or via at least one elastically designed second section 22. The second section 22 has at least one projection 26, which, in the illustrated embodiment, is realized as a plurality of protruding ribs. The at least one projection 26 is designed such that it is compressed or displaced into a first housing molded part half when the first molded body half 41 is assembled. This serves to compensate for manufacturing tolerances of the first molded body half 41, the first housing molded part half 51, and / or the measuring tube. The second section 22, like the first section 21, is made of a thermoplastic in the form of expanded polypropylene. The first molded body half 41 has a compression set in the second section 22. DVR according to ISO 1798 from 0 ≤ DVR ≤ 20%, in particular 5 ≤ DVR ≤ 15% and preferably DVR < 15%. Furthermore, the first molded body half 41 exhibits an elongation at break according to ISO 1798 of 10 to 20% and preferably of 14 to 16% in the second section 22. Another characteristic mechanical property of the first molded body half 41 is its tensile strength. This is between 400 and 1300 kPa in the second section 22, particularly between 600 and 1000 kPa and preferably between 700 and 880 kPa according to ISO 1798.

[0028] Furthermore, the first molded body half 41 has a projection 38 with a longitudinal axis that lies within the cross-section of the first molded body half 41. The cross-sectional area of ​​the projection 38 increases at least section by section along its longitudinal axis, particularly in the direction of a receptacle in a second molded body half (not shown) that is complementary to the projection 38. The projection 38 can be inserted into the receptacle, thereby forming a positive-locking closure. According to the illustrated embodiment, the first molded body half 41 also has a receptacle 39 in the form of an opening, which is complementary to a projection of the second molded body half. The receptacle 39 is arranged in a fourth section 40 of the first molded body half 41, which is elastically designed.This allows the fourth section 40 to be deformed in order to accommodate the projection of the second molded body half during assembly and to connect the two molded body halves 41, 42 to each other in a form-fitting manner in order to achieve sufficient fixation of these on the measuring tube.

[0029] Fig. 3 Figure 1 shows a longitudinal section through a magnetic-inductive flowmeter 7 as an example of a field device for automation technology according to the invention. The magnetic-inductive flowmeter 7 comprises a measuring tube 8 for guiding a flowable medium and two terminal process connections. The measuring tube 8 is a longitudinally welded steel tube with an electrically insulating liner applied to an inner surface. The measuring arrangement of the magnetic-inductive flowmeter includes a device 9 for measuring an induced measuring voltage in the flowing medium, in particular at least two diametrically arranged measuring electrodes, which are inserted and fixed in a medium-tight manner in a provided opening in the tube wall of the measuring tube 8, thus contacting the medium.The measuring arrangement further comprises a device 10 for generating a magnetic field penetrating the measuring tube 8, consisting of at least two diametrically arranged coils configured to generate a magnetic field with a main magnetic field axis that runs essentially perpendicular to a measuring electrode axis connecting the two measuring electrodes and to a longitudinal axis of the measuring tube 8. A level monitoring electrode and a reference electrode are also arranged on the measuring tube 8.

[0030] The electronic component 4, comprising the measuring circuit, operating circuit, and / or control circuit arranged on the printed circuit board, is housed in a cold-formed enclosure 5. The enclosure 5 comprises a first enclosure half 51, which is cold-formed and connected to a second enclosure half 52, which is cold-formed and arranged diametrically opposite each other. The enclosure 5 has an opening 6 in which a display glass 29, at least partially transparent, is arranged. A printed circuit board has a display 2 arranged on the first section of the printed circuit board, which is visible through the display glass 29. An outer surface of the measuring tube 8 and the first enclosure half 41, as well as the second enclosure half 42, each define a cavity in which the coils of the device 10 for generating the magnetic field are arranged.

[0031] Fig. 4 Figure 1 shows a schematic representation of a longitudinal section through a radar-based level gauge 43 as a further example of a field device in automation technology. Radar-based measurement methods have become established for measuring the fill level of contents in containers 18 because they are robust and require little maintenance. A key advantage of radar-based measurement methods is their ability to measure the fill level almost continuously. In the context of this patent application, the term "radar" refers to radar signals with frequencies between 0.03 GHz and 300 GHz. Common frequency bands used for level measurement are 2 GHz, 26 GHz, 79 GHz, and 120 GHz. The two common measurement principles are the pulse-time-delay principle (also known as "pulse radar") and the FMCW principle ("frequency modulated continuous wave").A level measuring device that operates according to the pulse-time-of-flight method is described, for example, in German patent application DE 10 2012 104 858 A1. For an example of a typical design of FMCW-based level measuring devices, reference is made to German patent application DE 10 2013 108 490 A1. The measuring principles of FMCW and pulse radar are also described in more detail in "Radar Level Detection," Peter Devine, 2000. The radar-based level measuring device 43 also has a housing 5 with a molded body 13 arranged therein. The molded body 13 has a first section with a recess in which an electronic component 4 is arranged. The properties of the first section are identical to those of the one described in [reference missing]. Fig. 1 und Fig. 2 shown and described field device of automation technology.

[0032] Fig. 5 shows a view from below of the first half of the molded body 41 from Fig. 2 The receptacle 19 for the electronic component is shown. Receptacle 19 is designed as a through opening. Also shown is receptacle 39 for receiving a projection to form a force-fit and / or form-fit connection. A third section 23, which is elastically designed, is also visible. This third section 23 has a projection 27 that is to be arranged in mechanical contact with an outer surface of a measuring tube or container and is designed as a sealing lip extending at least partially around the circumference of the measuring tube or container. The projection 27 is designed such that when the first half of the molded body 41 is attached to the measuring tube or container, the projection 27 is displaced or compressed. This allows manufacturing tolerances to be compensated for and mechanical stress and / or leaks to be reduced.The third section 23 is also a thermoplastic and / or an elastomer, or in a preferred embodiment an expanded polypropylene, which has a compression set. DVR according to ISO 1798 from 0 ≤ DVR ≤ 20%, in particular 5 ≤ DVR ≤ 15% and preferably DVR < 15%. Furthermore, the third section 23, in particular the cantilever 27, is designed such that an elongation at break according to ISO 1798 of 10 to 20% and preferably of 14 to 16% and / or a tensile strength according to ISO 1798 of 400 to 1300 kPa, in particular 600 to 1000 kPa and preferably of 700 to 880 kPa, is present.

[0033] Fig. 6 Figure 1 shows a perspective view of a centering device 34 for blocking tangential displacement of the molded body half within the housing molded part half and / or on the outer surface of the measuring tube. The centering device 34 has a groove 44 via which it can be materially connected to the inner surface of the housing molded part half. Furthermore, the centering device 34 has a hook 45 at one end, which is designed to engage in a receptacle in the molded body half and thus form a positive and / or force-fit connection between the molded body half and the housing molded part half.The centering device 34 is designed as a thin bent sheet metal part, which is designed to be springy at least in such a way that when the molded body half is inserted into the housing molded part half in an assembly direction, the hook 45 can be displaced at least section by section from the inner housing surface of the housing molded part half.

[0034] Fig. 7A Figure 1 shows a perspective view of a partially cut housing mold half 51 with a first mold half 41 to be inserted in a linear assembly direction (see arrow). The centering device 34 is materially bonded to the inner housing surface 24 of the first housing mold half 51 by means of a joining process, in particular welding. The first housing mold half 51 has at least one bending tab 53 in its second edge section 62 for forming a positive-locking connection with the (not shown) second housing mold half 52. To form the connection, the at least one bending tab 53 is bent so that it engages with the second edge section of the contacting second housing mold half in such a way that the two housing mold halves can no longer be separated from each other without either of the two housing mold halves having to be plastically deformed.Furthermore, the second edge section 62 of the first housing mold half 51 includes a circumferential fold 54, at least partially, to limit displacement of the second housing mold half in a longitudinal and / or transverse direction of the measuring tube during assembly of the two housing mold half(s), i.e., when both housing mold half(s) are joined but the bending tabs have not yet been bent. The fold 54 also engages in a recess in the second edge section of the second housing mold half. The recess can be formed as an opening in the second edge section of the second housing mold half or by a second edge section of the second housing mold half that is shorter than the second edge section of the first housing mold half. This allows the two housing mold half(s) to be centered more precisely relative to each other during assembly.The at least one bending tab 53 is monolithically connected to the fold 54 at least in sections.

[0035] Fig. 7B shows a section of a cross-section through the first housing molded part half 51 of the Fig. 7A with the first molded body half 41 arranged and fixed in the final assembly position. The first molded body half 41 has a receptacle 46 in conjunction with an undercut into which the hook 45 of the centering device engages.

[0036] Fig. 8 Figure 1 shows a section of a first embodiment of an edge region of a first housing component half in contact with an outer surface of a measuring tube. The housing 2 shown has a housing wall 47 which, together with the outer surface 25 of the measuring tube 8, defines a housing interior 48. The housing wall 47 has a first edge section 61 which is in direct contact, at least partially, with the outer surface 25 of the measuring tube 8 and is bent away from the housing interior 48, at least partially. According to the invention, at least the first edge section 61 is clamped to the measuring tube 8. This means that the housing is mounted and fastened to the measuring tube in such a way that the first edge section 61 is deformed and a mechanical stress remains in the housing, at least partially.

[0037] The first edge section 61 is free of any bending, at least in a longitudinal section. A groove in the housing wall, for example, is therefore not considered part of the first edge section 61 according to the invention. Furthermore, in the longitudinal section through the field device, the first edge section 61 has a first edge section longitudinal axis A (dashed line) which forms an angle with the outer surface 25 of the measuring tube 8. α The section intersects, where α has an angular dimension between 1° and 10° or 5°. A solid line is shown as a reference to the longitudinal axis A of the edge section, representing a longitudinal axis of the measuring tube.

[0038] The shaped body 13 is arranged inside the housing 48 and has an outer shaped body surface 25. In the embodiment of the Fig. 8 The outer surface of the molded body 13, the housing wall 47, and the outer surface 58 define a sealing seat 59 for a sealant, particularly a liquid one (not shown). The molded body 13 also has a recess 63 for forming the sealing seat 59, which is wedge-shaped at least in sections. The sealant comprises at least a proportion of polyurethane, polysiloxane, polyethylene, and / or an epoxy resin. The molded body 13 is at least partially formed from a particle foam comprising at least polystyrene, polyphenylene sulfide, expanded polypropylene, and polyurethane.

[0039] Fig. 9 shows a section of a second embodiment of an edge region of a first housing molded part half in contact with an outer surface of a measuring tube. The difference to the embodiment of the Fig. 8 The housing wall 47 has a groove 56 on an inner housing surface for stiffening the housing wall 47, which in addition to stiffening also serves as a sealing seat, so that at least in sections a sealing element (not shown) is arranged in the groove 56. Furthermore, the Fig. 9 a projection 27 which is in mechanical contact with an outer surface of the measuring tube and which is designed at least partially as a sealing lip extending around the circumference of the measuring tube or the container.

[0040] Fig. 10 Figure 1 shows a section of an edge region of a first housing half 51 in contact with a second housing half 52. The first housing half 51 and the second housing half 52 each have a second edge section 62, via which they are in direct contact with each other, at least partially. The first housing half 51 and the second housing half 52 are positively and / or force-fitted to each other via bending tabs (not shown) and additionally bonded by the liquid-applied sealant 57. The sealant 57 is arranged in a sealing seat 59 formed by the mutually contacting second edge sections 62, which is bounded by the two housing halves at least in the radial direction of the measuring tube 8. The sealing seat 59 is wedge-shaped, at least partially.

[0041] Fig. 11 shows a perspective view of a cutaway representation of a sealing seat between the first housing mold half and the second housing mold half. Fig. 11 differs from the Fig. 10 This is achieved essentially by the fact that, in addition to the sealing seat 59, the two second edge sections 62 together define a collection volume 64 for receiving sealant displaced in the expansion direction (not shown). This is realized by bending a portion of the second edge section 62, whereby the second edge sections 62, which are in contact with each other after assembly, also further define the collection volume 64 in the direction of the measuring tube. Alternatively, the volume designated as the collection volume 64 can assume the function of the sealing seat, i.e., the sealant is applied in liquid form in one of the bent sections, and when the two housing halves are clamped and fastened, the excess sealant is displaced towards the volume designated as the sealing seat 59 in this embodiment, and the sealing seat 59 thus assumes the function of the collection volume.

[0042] The illustrated second edge sections 62 each have, at least in one cross-section through the field device, a second edge section longitudinal axis C (dotted line) that runs parallel to an axis X (solid line) lying in a median plane. This median plane is defined by a longitudinal axis of the measuring tube and a transverse axis perpendicular to it. It passes through at least one contact point between the first housing half and the second housing half, in particular through the contact points of the second edge sections 62.

[0043] According to an advantageous embodiment, the second edge sections 62 are configured such that they have a second edge section longitudinal axis B (dashed line) which intersects the median plane at an angle β, where β has an angle of 1° to 10° or 5°. The alternative second edge section longitudinal axis B is also in the Fig. 11 as shown. Alternatively, the second edge section longitudinal axis B can transition into the second edge section longitudinal axis C after clamping and joining the two housing mold halves. Bezugszeichenliste

[0044] Field device of automation technology 1 Display 2 Measuring arrangement 3 Electronic component 4 Housing 5 Opening 6 Magnetic-inductive flow meter 7 Measuring tube 8 Device 9 For measuring an induced measuring voltage Device 10 For generating the magnetic field Molded body 13 Container 18 Receptacle 19 Undercut 20 First section 21 Second section 22 Third section 23 Inner housing surface 24 Outer molded body surface 25 Projection 26 Projection 27 Circuit board 28 Display glass 29 Locking lug 30 First circuit board section 31 Second circuit board section 32 Third circuit board section 33 Centering device 34 Undercut 35 Guide rail 36 Electronic components 37 Projection 38 Receptacle 39 Fourth section 40 First molded body half 41 Second molded body half 42 Radar-based level sensor 43 Bead 44 Hook 45 Receptacle 46 Housing wall 47 Housing interior 48 First housing molded part half 51 Second housing molded part half 52 Bend tab 53 Fold 54Recess 55, groove 56, sealant 57, outer measuring tube shell surface 58, seal seat 59, sealant 60, first edge section 61, second edge section 62, recess 63, collection volume 64

Claims

1. An automation technology field device (1), comprising: • A measuring tube (8) for conducting a flowable medium, • a measurement arrangement (3) for determining a physical and / or chemical measured variable of the medium, wherein the measurement arrangement (3) is at least partially arranged on the measuring tube (8), • a housing (5) for housing at least one electronic component (4) for operating the measurement arrangement (3), regulating a control variable of the measurement arrangement (3), determining a measured value for the measured variable, and / or analyzing the measured variable, wherein the housing (5) is arranged on an outer lateral surface(58) of the measuring tube (8) and at least partially covers the measurement arrangement (3), wherein the housing (5) has a housing wall (47) which, together with the outer lateral surface (58) of the measuring tube (8), delimits a housing interior (48), wherein the housing wall (47) has a first edge section (61) which is in direct contact with the outer lateral surface (58) of the measuring tube (8) at least in sections, wherein the first edge section (61) is bent away from the housing interior (48) at least in sections, wherein the first edge section (61) is not bent, characterized in that at least the first edge section (61) has a force-fit connection with the measuring tube (8), wherein the first edge section (61) has a first edge section longitudinal axis A at least in a longitudinal section through the field device (1), which intersects the outer lateral surface (58) of the measuring tube (8) at an angle α, wherein α has an angular dimension between 1° and 10°, and wherein the housing (5) is installed on and attached to the measuring tube (8) in such a way that the first edge section (61) is deformed as a result and stress remains in at least some sections of the housing (5).

2. The field device (1) as claimed in claim 1, wherein the housing (5) comprises an, in particular cold-formed, first half of the housing molded part (51) and an, in particular cold-formed, second half of the housing molded part (52), wherein the first half of the housing molded part (51) and the second half of the housing molded part (52) are diametrically arranged and attached to each other.

3. The field device (1) as claimed in the preceding claim, wherein the first half of the housing molded part (51) and the second half of the housing molded part (52) each have a second edge section (62), wherein the second edge sections (62) are in direct contact with each other at least in sections, wherein the edge sections (61, 62) each have a second edge section longitudinal axis B at least in a cross-section through the field device (1), which intersects a center pane at an angleβ, wherein the angle β has an angular dimension from 1° to 10°, wherein the center pane is formed by a longitudinal axis of the measuring tube (8) and a transverse axis X running perpendicular thereto, wherein the center pane extends through at least one contact point of the second edge sections (62).

4. The field device (1) as claimed in claim 2 and / or a dependent claim, wherein the first half of the housing molded part (51) has in the second edge section (62) at least one formed sheet (53) for forming a force-fit connection with the second half of the housing molded part (52), wherein the at least one formed sheet (53) is bent over and is connected to the second edge section (62) of the second half of the housing molded part (52) that is in contact.

5. The field device (1) as claimed in claim 2 and / or a dependent claim, wherein the second edge section (62) of the first half of the housing molded part (51) has a folded edge (54) which surrounds at least some sections for limiting a movement of the second half of the housing molded part (52) in a longitudinal direction and / or a transverse direction of the measuring tube (8), wherein the folded edge (54) engages in a recess in the second edge section (62) of the second half of the housing molded part (52).

6. The field device (1) as claimed in the preceding claim, wherein the at least one formed sheet (53) is monolithically connected to the folded edge (54).

7. The field device (1) as claimed in at least one of the preceding claims, wherein the housing (5) has beading (56) on the inner housing lateral surface (24) to reinforce the housing wall (47), wherein a sealant (57) is arranged in at least some sections of the beading (56).

8. The field device (1) as claimed in at least one of the preceding claims, wherein the measurement arrangement (3) has a device (10) for generating a magnetic field which penetrates the measuring tube (8) and at least two measuring electrodes for determining a measuring voltage induced in the medium, wherein the device (10) for generating the magnetic field and the at least two measuring electrodes are at least partially arranged on the outer lateral surface (58) of the measuring tube.