Measurement tube, receiving unit and magnetic-inductive flowmeter

Abstract

The present invention relates to a measuring tube (1) for conducting a flowable medium in a longitudinal direction, the measuring tube comprising: - a measuring tube body (2) specifically designed to be electrically insulating, the measuring tube body (2) having an integrally designed support (34), the measuring tube body (2) having a mounting surface for mechanically detachably mounting the measuring tube (1) in a receiving unit (22), particularly at a location defined by the mounting surface; - at least two measuring electrodes (3) specifically radially opposed to each other in the measuring tube body (2) for forming current contact with the medium; and - at least one pole piece (35) formed of a single sheet metal component or of multiple sheet metal components, wherein the multiple sheet metal components are stacked and interconnected, particularly in the longitudinal direction of the pole piece (35), the pole piece (35) being located in the support (34). The invention also relates to a receiving unit (22) and a magnetic induction flowmeter (58).

Description

Technical Field

[0001] This invention relates to a measuring tube, a receiving unit, and a magnetic induction flowmeter. Background Technology

[0002] Magnetic induction flow meters are used to determine the flow rate and volumetric flow rate of a medium in a process pipeline. A magnetic induction flow meter has a magnet system that generates a magnetic field perpendicular to the flow direction of the medium. A single coil is typically used for this purpose. To achieve a predominantly uniform magnetic field, pole pieces are additionally formed and attached such that the magnetic field lines extend substantially perpendicular to the transverse axis of the measuring pipe or parallel to the vertical axis of the measuring pipe across the entire cross-section of the pipe. Measuring electrodes attached to the lateral surface of the measuring pipe tap the voltage or potential difference, which is perpendicular to the flow direction and occurs when the magnetic field is applied and the conductive medium flows in the flow direction. Because, according to Faraday's law of induction, the tapped measuring voltage depends on the velocity of the flowing medium, the flow rate u, and, with the aid of the known pipe cross-section, the volumetric flow rate... It can be determined from the induced measured voltage U.

[0003] To date, only a few flow meters utilize Faraday's law of magnetic induction and are suitable for so-called disposable applications. Disposable applications require parts that can be replaced in contact with the medium. In magnetic induction flow meters, these would be, respectively, parts of the measuring electrode and measuring tube, such as the liner or the entire measuring tube body.

[0004] DE 10 2016 118 064 A1 teaches a magnetic induction flowmeter having a U-shaped measuring tube holder for a replaceable measuring tube. The magnet system is located within the measuring device housing, and mating contacts of the measuring electrodes mounted in the measuring tube are located within the measuring tube holder.

[0005] The drawback of known magnetic induction flowmeters for single-use applications is that the uniformity of the magnetic field in the measuring section of the measuring tube can only be achieved by increasing energy consumption. Summary of the Invention

[0006] The purpose of this invention is to provide a magnetic induction flowmeter for single-use applications that requires less energy for a substantially uniform magnetic field in the measuring section of the measuring tube.

[0007] The measuring tube according to the present invention for conducting a flowable medium in the longitudinal direction comprises:

[0008] - Measuring tube, which is specially designed to be electrically insulated.

[0009] The measuring tube body has an integrally formed support.

[0010] The measuring tube body has a mounting surface for mechanically detachably mounting the measuring tube in the receiving unit, particularly at a position defined by the mounting surface;

[0011] - At least two measuring electrodes, specifically arranged radially opposite each other within the measuring tube, for forming current contact with the medium; and

[0012] - At least one pole shoe, said pole shoe being formed of a single sheet metal component or of multiple sheet metal components, wherein said multiple sheet metal components are stacked and interconnected, particularly in the longitudinal direction of said pole shoe.

[0013] The pole shoe is located in the bracket.

[0014] Pole shoes with mounted coils are typically installed in magnetic induction flow meters, where the pole shoes are attached to the lateral surface of the measuring tube. They surround the measuring tube and span a region in which the magnetic field in the medium is substantially uniform or extends perpendicular to the horizontal axis. Magnetic induction flow meters for single-use applications have a receiving unit in which the measuring circuit, operating circuit, and magnetic field generating device are arranged. If pole shoes are provided, they are arranged within the housing of the receiving unit. Replaceable measuring tubes typically do not have any components of the magnetic field generating device. According to the invention, the measuring tube body of the measuring tube has a support in which the pole shoes are located. In this case, the pole shoes are also replaced for each measuring tube to be replaced. As a result, the distance between the channel of the measuring tube, which can be supplied with the medium, and the magnetic field generating device is reduced, and the magnetic field extending through the channel of the measuring tube is more uniform.

[0015] Advantageously, the measuring tube has two opposing supports, each with a pole shoe arranged in the support.

[0016] One embodiment specifies that the pole shoe has a first end face and a second end face, the first end face and the second end face defining the pole shoe in the longitudinal direction.

[0017] The measuring tube extends along the first end face and the second end face, and particularly completely covers the first end face and the second end face respectively in the longitudinal direction.

[0018] The advantage of this embodiment is that the pole shoe is fixed by a cover to prevent movement in the longitudinal direction of the measuring tube.

[0019] One embodiment specifies that the pole shoe has a first side and a second side.

[0020] The first side connects the first end face to the second end face.

[0021] The second side connects the first end face to the second end face.

[0022] The measuring tube extends along the first side [l1] and the second side, and in particular completely covers the first side and the second side.

[0023] The advantage of this embodiment is that the pole shoe is also additionally secured to prevent movement in the lateral direction of the measuring tube. Advantageously, the support is designed so that the pole shoe is connected to the measuring tube body in a form-locking manner.

[0024] One embodiment specifies that the base surface of the pole shoe is not covered by the measuring tube or is only partially covered by the measuring tube.

[0025] The base surface connects the first end face and the second end face.

[0026] The base surface connects the first side surface to the second side surface.

[0027] An open base surface is used to contact the coil core, which is part of the magnetic field generating device arranged in the receiving unit. It is important to note that no inclusions should appear between the base surface and the coil core. Therefore, the base surface and the end section of the coil core are complementary. According to an advantageous embodiment, the base surface is planar. Pole shoes are used to guide the magnetic field generated by the coil and guided by the coil core all the way to the channel and across the measuring section, where the measuring electrodes are also arranged.

[0028] One embodiment specifies that the measuring tube is a single piece.

[0029] The measuring tube body is formed by a one-time forming method, particularly by injection molding.

[0030] The pole shoe is formed in a secondary process, in part by the encapsulation material forming the measuring tube body, through the primary forming method, particularly the injection molding method.

[0031] The advantage of this embodiment is that it allows for the simple and cost-effective production of a measurement tube with an integrated measuring electrode and an integrated pole piece. Therefore, the pole piece does not need to be subsequently inserted into the guide.

[0032] One embodiment specifies that a longitudinal plane divides the measuring tube into two sides, wherein the longitudinal axis of the measuring tube extends in the longitudinal plane, and the longitudinal plane extends perpendicular to the electrode axis connecting the two measuring electrodes.

[0033] The measuring tube includes exactly one field guide for guiding the magnetic field, which is arranged on one of the two sides of the measuring tube body.

[0034] The field guide is connected to the measuring tube via a shape-locking mechanism.

[0035] The field guide has at least one, and preferably two, open contact surfaces.

[0036] The field guide is configured to connect the two coil cores of the magnetic field generating device to each other after the measuring tube is supported in the receiving unit.

[0037] The advantage of this embodiment is that it allows for a closed magnet system without adversely affecting the ease of installation of the measuring tube within the measuring tube support. The magnetic field generating device is modular. This means that a portion of the magnetic field generating device is arranged on the measuring tube. In the current case, these are one or more pole shoes and field guides. In the installed state, the magnet system is partially open. The magnet system is only closed when the measuring tube is inserted into the measuring tube support and the field guide of the measuring tube comes into contact with the magnetic field generating device.

[0038] A receiving unit according to the present invention for receiving a replaceable measuring tube (particularly a measuring tube according to the present invention) comprises:

[0039] -case,

[0040] The housing includes a measuring tube support;

[0041] - A magnetic field generating device, said magnetic field generating device being used to generate a magnetic field that extends through the measuring tube support.

[0042] The magnetic field generating device includes a coil and a coil core.

[0043] The magnetic field generating device is arranged inside the housing;

[0044] - A measurement circuit, the measurement circuit being used to determine the measurement voltage applied to the measurement electrodes of the measurement tube;

[0045] - An operating circuit, the operating circuit being used to operate the magnetic field generating device;

[0046] - At least two terminal contacts, said at least two terminal contacts being designed to electrically and mechanically detachably connect the measuring electrodes of the measuring tube to the measuring circuit.

[0047] The contact area of ​​the corresponding terminal contact protrudes from the housing and extends into the measuring tube support.

[0048] One embodiment specifies that the coil core extends through an opening in the measuring tube support.

[0049] The coil core is designed and arranged in the measuring tube support such that when the measuring tube is arranged in the measuring tube support, contact is generated between the coil core and the pole shoe.

[0050] The advantage of this embodiment is that there is no insulation separation between the coil core and the pole shoe, which would reduce the magnetic field extending through the channel of the measuring tube.

[0051] One embodiment specifies that the measuring tube support, perpendicular to the installation direction and perpendicular to the longitudinal direction of the measuring tube body, is defined by the surfaces of two legs.

[0052] The measuring tube support is defined by a base surface in the installation direction.

[0053] One embodiment specifies that the coil is arranged behind the base surface in the mounting direction.

[0054] The coil core has a first coil core segment that extends through the coil.

[0055] The coil core has a second coil core segment that extends from the first coil core segment in the direction of one of the two leg surfaces.

[0056] Such embodiments have a simplified structure and can be easily installed in a receiving unit. Preferably, the coil core is formed from sheet metal parts or from multiple stacked sheet metal parts.

[0057] One embodiment specifies that the magnetic field generating device has two coils, each coil having a coil core that extends through the interior of the coil.

[0058] The connection between the two coil cores is achieved via exactly one field guide.

[0059] The magnetic field generating device has two contact surfaces, each of which serves as a contact surface for a field guide arranged on the measuring tube.

[0060] The contact surface is arranged on the end face of the housing.

[0061] The advantage of this embodiment is that it allows for field guidance along the measuring electrodes around both sides of the measuring section. According to the invention, the partially open magnet system is enclosed by field guides arranged within the measuring tube.

[0062] The magnetic induction flowmeter according to the present invention comprises:

[0063] - A receiving unit, particularly a receiving unit according to the present invention.

[0064] - A measuring tube for conducting a flowable medium in the flow direction, the measuring tube being particularly according to the invention.

[0065] The measuring tube is mechanically detachably connected to the receiving unit, particularly by friction locking and / or shape locking.

[0066] One embodiment specifies that the pole shoe arranged on the measuring tube is in contact with the coil core extending through an opening in the measuring tube support.

[0067] This results in optimal transmission of the magnetic field from the coil core to the pole shoes.

[0068] One embodiment specifies that the magnetic field generating device arranged in the housing of the receiving unit has two coils.

[0069] Each of the two coils has at least one coil core, which extends through the respective coil.

[0070] The field guide of the measuring tube connects the two coil cores to each other.

[0071] Therefore, by inserting the measuring tube and contacting the field guide arranged in the measuring tube, the partially open magnet system of the magnetic field generating device is enclosed in the receiving unit. Attached Figure Description

[0072] The invention will be explained in more detail with reference to the following figures. As shown below:

[0073] Figure 1 This is a perspective view of an embodiment of the receiving unit;

[0074] Figure 2 Is it through Figure 1 A longitudinal section of an embodiment of the receiving unit shown;

[0075] Figure 3 It is the terminal contact from Figure 2 A close-up view of the longitudinal section;

[0076] Figure 4 From Figure 1 A close-up view of the cross-section of the receiving unit (particularly a measuring tube holder with an inserted measuring tube) and a close-up view of the cross-section of the receiving unit (particularly a measuring tube holder without an inserted measuring tube).

[0077] Figure 5Is it through Figure 1 A longitudinal section of the embodiment of the receiving unit (particularly through the fixing device) shown, and a close-up view of the measuring tube support;

[0078] Figure 6 Is it through Figure 1 The cross-section of the receiving unit shown (particularly through the fixing device);

[0079] Figure 7 This is a perspective view of another embodiment of a receiving unit with an inserted measuring tube;

[0080] Figure 8 Is it through Figure 7 The illustration shows a longitudinal section of the receiving unit embodiment, a close-up view of the measuring tube support, and a close-up view of the cross section of the measuring tube support with the inserted measuring tube.

[0081] Figure 9 It passes through a measuring tube with an insertion point. Figure 7 A cross-section of an embodiment of the receiving unit shown;

[0082] Figure 10 This is a perspective view of an embodiment of the measuring tube; and

[0083] Figure 11 It is a cross-section through another embodiment of the receiving unit and measuring tube. Detailed Implementation

[0084] Figure 1 A perspective view of an embodiment of the receiving unit 22 is shown. The receiving unit 22 includes a housing 23 with a measuring tube support 24. The measuring tube support 24 is used to receive and guide the measuring tube. For the current receiving unit 22, the measuring tube must be inserted straight in the mounting direction. The measuring tube support 24 is defined in the mounting direction by a base surface 31. The base surface 31 is part of the housing wall. Furthermore, the measuring tube support 24 is defined in a direction perpendicular to the mounting direction and perpendicular to the longitudinal direction of the measuring tube 1 by two leg surfaces 46.1, 46.2. The leg surfaces 46.1, 46.2 may extend in multiple planes. Two openings are formed in the leg surface 46.2, through which a fixing body 53 extends. The fixing body 53 is part of a fixing device and has an elastic design. This means that when the measuring tube is inserted into the measuring tube support 24, a force perpendicular to the mounting direction causes the fixing body to shift in a direction inside the housing. If the measuring tube is in the mounting position, the spring presses the fixing body into the support disposed in the measuring tube body.

[0085] Terminal contacts 28.1, 28.2, and 28.3, having contact areas 29, are arranged in the leg surface 46.1, wherein these contact areas extend into the measuring tube holder 24. The terminal contacts 28.1, 28.2, and 28.3 are resiliently designed and connected to the measuring circuit. When the measuring tube is inserted, the terminal contacts 28.1, 28.2, and 28.3 shift in a direction within the housing. The resilient design ensures that, in the final installed state of the measuring tube, the terminal contacts 28.1, 28.2, and 28.3 move in the direction of their initial position, thereby forming mechanical contact with the assigned measuring electrode or the reference electrode of the measuring tube. The connection between the terminal contacts 28.1, 28.2, and 28.3 and the corresponding measuring electrode or reference electrode is form-locked and / or friction-locked.

[0086] A jack connector 32 is disposed in the base surface 31 and is used to connect a temperature sensor disposed in a measuring tube to a measuring circuit disposed in a housing. The jack connector 32 is designed to complement the contact portion of the temperature sensor. In an advantageous embodiment, the contact portion of the temperature sensor is designed as a jack plug, and the jack connector 32 is designed as a jack socket.

[0087] Figure 2 A longitudinal section through the receiving unit 22 is shown. A measuring circuit 30 and an operating circuit 44 are arranged within the housing 23 of the receiving unit 22. The measuring circuit 30 is configured to measure the measuring voltage on the measuring electrodes of the measuring tube. For this purpose, it is connected to terminal contacts 28, which form electrical contact with the measuring electrodes 3 when the measuring tube 1 is inserted. The operating circuit 44 is configured to apply a coil signal to the coil 26. Furthermore, a magnetic field generating device 25 is arranged inside the housing 23. The magnetic field generating device 25 includes a coil core 27 and a coil 26, wherein the coil core 27 extends through the coil cross-section. The coil 26 is arranged in the mounting direction behind the base surface 31. The coil core 27 has a first segment extending through the coil 26, and two segments extending from the first segment in directions toward the leg surfaces 46.1, 46.2. In the longitudinal section of the coil core, the coil core 27 presents a C-shape or horseshoe shape. The magnetic field generating device 25 has the shape typically used in polarized motors. The coil core 27 is preferably designed as a single piece. The coil core 27 may be formed from a solid magnetic material, a single sheet metal component, or multiple sheet metal components stacked and interconnected, particularly in the lateral direction of the pole shoe. The coil core 27 has a first coil core segment 48.1 and a second coil core segment 48.2, wherein the first coil core segment extends through the coil 26, and the second coil core segment extends from the first coil core segment 48.1 in the direction of one of the two (particularly parallel) leg surfaces 46.1, 46.2.

[0088] In the measuring tube holder 24, the measuring tube 1 is arranged in a mechanically detachable manner, particularly in a form-locking and / or friction-locking manner. In the illustrated embodiment, the coil core 27 is separated from the measuring tube 1 at least by the wall of the housing 23.

[0089] Figure 3 It shows Figure 2A close-up view of the longitudinal section. Terminal contacts 28.1 and 28.2 are arranged in the leg surface 46.1 and contact the measuring electrodes 3.1 and 3.2 via contact areas 29.1 and 29.2. Each measuring electrode 3.1 and 3.2 has a measuring electrode body 9, which has a first measuring electrode portion 10.1 and a second measuring electrode portion 10.2, wherein the first measuring electrode portion is arranged in a first region 5.1 of the support, and the second measuring electrode portion is arranged in a second region 5.2, wherein the longitudinal axes 6.1 and 6.2 of the two measuring electrode portions 10.1 and 10.2 are oriented differently. In the illustrated embodiment, the measuring electrodes 3.1 and 3.2 are each designed as two parts and arranged in a support within the measuring electrode body. At least the first measuring electrode portion 10.1 of the measuring electrodes 3.1 and 3.2 has been at least partially secondary-molded by injection molding. After the injection molding process, the second measuring electrode portion 10.2 has been inserted into the second region 5.2 of the provided support. The front region 11 of the first measuring electrode portion 10.1 extends within a channel of the measuring tube 2 suitable for conducting media. Furthermore, the first measuring electrode portion 10.1 has a support 13 located in an end region 12 complementary to the front region 14 of the second measuring electrode portion 10.2. The front region 14 of the second measuring electrode portion 10 is arranged within the support 13 of the first measuring electrode portion 10.1. The second measuring electrode portion 10.2 has an end region 15 with a support 16 for receiving a portion of a terminal contact 28. The longitudinal axis of the first measuring electrode portion 10.1 corresponds to the electrode axis 21. The longitudinal axis of the second measuring electrode portion 10.2 is inclined to the longitudinal axis of the first measuring electrode portion 10.1. In the illustrated embodiment, the longitudinal axis of the first measuring electrode portion 10.1 and the longitudinal axis of the second measuring electrode portion 10.2 form an angle of approximately 90°. Both the first measuring electrode portion 10.1 and the second measuring electrode portion 10.2 have a basic cylindrical shape. The support 14 of the first measuring electrode portion 10.1 also has a basic cylindrical shape. The support 16 of the second measuring electrode portion 10.2 is designed as a convex recess, thus facilitating the insertion of the terminal contacts 28.1, 28.2. The second measuring electrode portion 10.2 of the first measuring electrode 3.1 is shorter than the second measuring electrode portion 10.2 of the second measuring electrode 3.2. This relates to the arrangement of the terminal contacts 28.1, 28.2 within the housing 23. The terminal contact 28.2 is located in the input portion of the measuring tube support 24, while the terminal contact 28.1 is positioned closer to the base surface of the measuring tube support 24. The contact area 29.1 of the first terminal contact 28.1, located downstream of the second terminal contact 28.2 in the mounting direction, is offset in a direction perpendicular to the mounting direction and the longitudinal direction of the measuring tube body, or in a direction perpendicular to the longitudinal plane of the measuring tube body 2 extending through the electrode axis 21.This means that the contact area 29.1 extends further into the measuring tube holder 24 than the contact area 29.2 of the second terminal contact 28.2. This allows the measuring tube 1 to be easily and safely inserted into the measuring tube holder 24. The terminal contact 28 has a resilient design. When the measuring tube 1 is inserted, the cross-section of the measuring tube body 2 causes the corresponding contact area 29 of the terminal contact 28 to shift in a direction within the housing. The spring is compressed. If the measuring tube 1 is in the installed state, the spring drives the contact area to the initial position, wherein the contact area is guided into the holder 16 of the second measuring electrode portion 10.2 and forms a shape lock with it or at least forms mechanical and electrical contact with it. The contact area 29 of the terminal contact 28 has a pin-shaped design and is rounded.

[0090] The measuring electrode bodies 9 of measuring electrodes 3.1 and 3.2 are formed of a material including metal. In the front region of the contact medium of measuring electrodes 3.1 and 3.2, the corresponding measuring electrodes 3.1 and 3.2 are shaped as pointed electrodes.

[0091] Figure 4 Close-up views of the receiving unit (particularly the measuring tube holder 24 with the inserted measuring tube 1) and the receiving unit (particularly the measuring tube holder 24 without the inserted measuring tube 1) are shown in cross-section. The measuring tube 1 includes a measuring electrode 3.1 that extends at least partially into a channel suitable for conducting the medium. A temperature sensor 17 is arranged offset in the longitudinal direction of the measuring tube 1. The temperature sensor 17 is adapted to determine a measurement variable proportional to the medium temperature. A measuring circuit arranged in the housing is configured to communicate with the temperature sensor 17. The temperature sensor 17 contacts a plug connector 19 arranged in the base surface of the measuring tube holder 24. By inserting the measuring tube in the mounting direction, the connector of the temperature sensor 17, complementary to the plug connector 19, is inserted into or into the plug connector 19. A reference electrode 33 for grounding the medium is arranged in the lower portion of the measuring tube 1, i.e., below the longitudinal plane of the measuring tube. The reference electrode 33 is designed as a pointed electrode and is connected to the measurement circuit via a third terminal contact 28.3. In the installed state, the contact area 29.3 of the third terminal contact 28.3 extends within the support of the reference electrode 33. The third terminal contact 28.3 also has a flexible design. The first measuring electrode 3.1 or the first terminal contact 28.1 is located in a first cross-sectional plane 18.1, while the reference electrode 33 is located in a second cross-sectional plane 18.2, which is arranged to be offset in the longitudinal direction of the measuring tube 1.

[0092] Figure 5 It shows crossing Figure 1The illustration shows a longitudinal section of an embodiment of the receiving unit 22 (particularly through the fixing device 54), and a close-up view of the measuring tube support 24. The fixing device 54 includes a fixing body 53 and a spring arranged on the inner surface 57 of the housing 23. In the initial state, a portion of the fixing body 53 abuts against the inner side of the housing wall, particularly on the portion of the wall where the leg surface 46.2 is located. An opening 56 is located in the leg surface 46.2, through which the fixing body 53 extends. The fixing body 53 extends into the measuring tube support 24. The fixing body 53 includes a pressing surface 59 having a normal vector formed by the sum of two base vectors (i.e., a first base vector pointing only opposite to the installation direction and a second base vector pointing towards the measuring tube support 24 and extending perpendicularly to the first base vector).

[0093] A plug connector 19 is arranged in the base surface 47 of the measuring tube holder 24. This plug connector is designed as a sleeve, specifically as a socket sleeve. The plug connector has a longitudinal axis extending parallel to the axis of the measuring electrode of the measuring tube. The plug connector 19 is arranged to be offset relative to the coil 26 in the longitudinal direction of the measuring tube (not shown).

[0094] Figure 6 It shows crossing Figure 1 The illustrated receiving unit 22 is shown in cross-section (particularly through the fixing device 54). The fixing device 54 includes two fixing bodies 53.1 and 53.2 arranged in the housing 23, each having a resilient design. The fixing bodies 53.1 and 53.2 are arranged offset in the longitudinal direction of the measuring tube support 24. The coil core 27 of the magnetic field generating device extends between the fixing bodies 53.1 and 53.2. The fixing device 54 is arranged only on one side of the measuring tube support 24. Terminal contacts 28 for the measuring electrode and the reference electrode are mounted on opposite sides. Two openings 56.1 and 56.2 through which each of the fixing bodies 53.1 and 53.2 extends are located in the leg surface 46.2.

[0095] The fixing body 53 has a pressing surface 59, which ensures that the measuring tube 1 is inserted straight into the measuring tube holder 24 when the contact between the pressing surface 59 of the fixing body 53 and the pressing surface 55 of the measuring tube 1 is converted into movement of the fixing body 53 in a direction perpendicular to the installation direction inside the housing. Therefore, the pressing surface 59 has a normal vector formed by the sum of two base vectors (i.e., a first base vector pointing only opposite to the installation direction and a second base vector pointing towards the measuring tube holder 24 and extending perpendicularly to the first base vector).

[0096] Figure 7 A perspective view of another embodiment of the receiving unit 22 with the inserted measuring tube 1 is shown. Figure 7The illustrated embodiments are similar to the foregoing embodiments (see Figures 1 to 6 The main differences lie in the embodiments of the measuring tube 1, the magnetic field generating device arranged in the housing, and the measuring tube support 24.

[0097] Figure 8 It shows crossing Figure 7 The embodiments shown include a longitudinal section of the receiving unit 22, a close-up view of the measuring tube support 24, and a close-up view of the cross-section of the measuring tube support 24, each with an inserted measuring tube 1. The magnetic field generating device 25 shown substantially corresponds to... Figure 2 The magnetic field generating device 25 is described above. The main difference lies in that two segments of the coil core 27 each extend through the opening 45. The coil core 27 is formed as a solid magnetic core, or as a single sheet metal component, or as multiple sheet metal components stacked and interconnected, particularly in the longitudinal direction of the pole shoes, in a single piece or multiple component form. The same applies to the pole shoes 35. Unlike typically, the pole shoes 35 are not arranged within the housing 23 but rather on the measuring tube 2. The pole shoes 35 have a base surface 40 that contacts the coil core 27 in the installed state. Therefore, the magnetic field generated by the coil is guided through the coil core to the pole shoes 35 arranged on the measuring tube 1, which at least partially spans the channel of the measuring tube, thereby forming a substantially uniform magnetic field within the channel.

[0098] In the illustrated embodiment, the measuring tube 1 includes two radially opposed pole shoes 35.1, 35.2. The pole shoes 35.1, 35.2 are partially secondary-molded from the encapsulation compound forming the measuring tube body 2 by injection molding, but to the extent that at least the sides 38, 39 and end faces 36, 37 are at least partially covered and the base surface 40 is free or partially exposed, such that there is no unfavorable intermediate layer between the base surface 40 of the pole shoe 35 and the coil core 27. The base surface 40 is designed to be complementary to the corresponding end segment of the coil core 27. In the illustrated embodiment, the base surface 40 and the associated end segment of the coil core 27 are designed as planar surfaces.

[0099] The embodiment of the terminal contact corresponds to Figure 3 The example shown.

[0100] Figure 9 It shows crossing Figure 7 The cross-section shown is of an embodiment with a receiving unit 22 containing an inserted measuring tube 1, wherein the measuring tube 1 is inserted into the measuring tube holder 24 in a form-locking and friction-locking manner. Figure 6In contrast to the illustrated embodiment, the measuring tube 1 has a support 34 into which a pole piece 35 is inserted. The support 34 is designed such that the pole piece 35 is form-fitted to the measuring tube body 2. End faces 36 and 37 contact the measuring tube body 2, as well as the sides 38 and 39. Because the pole piece 35 is formed secondary using the encapsulation material forming the measuring tube body 2, or because the pole piece is integrally formed within the measuring tube body 2, it cannot subsequently be removed from the support 34. The base surface 40 of the pole piece 35 contacts the coil core 27, which extends through an opening in the end face of the measuring tube support. The arrangement and embodiment of the terminal contacts 28 and the fixing device 54 correspond to the previously illustrated embodiment. The measuring tube 1 is connected to the hose system via a process connection 60.

[0101] Figure 10 A perspective view of an embodiment of the measuring tube 1 is shown. The measuring tube 1 has two radially opposite measuring electrodes 3.1, 3.2, each formed in two parts. The first measuring electrode part has a first longitudinal axis 6.1, which extends perpendicularly to the longitudinal axis 7 of the measuring tube 1 and corresponds to the electrode axis 21. The second measuring electrode part has a second longitudinal axis 6.2 extending perpendicularly to the first longitudinal axis. Furthermore, the measuring tube 1 has a temperature sensor 17 with a plug connector, which is complementary to a plug connector arranged in the receiving unit (particularly in the measuring tube support). The shown plug connector of the temperature sensor 17 is a plug. The electrode axis 21, the reference axis 20 of the temperature sensor 17, and the longitudinal axis of the measuring tube body 7 lie in a common longitudinal plane 8.

[0102] The measuring tube 2 has two radially opposite supports 34, each for a pole piece 35, wherein a reference line connecting the pole pieces 35 intersects perpendicularly with the longitudinal axis 7 of the measuring tube 1. The pole pieces 35 are integrally formed in the measuring tube 2 such that only the base surface 40 is exposed, which contacts the corresponding coil core arranged in the receiving unit. In the illustrated embodiment, the base surface 40 is planar.

[0103] Furthermore, the measuring tube 1 has two supports 52.1 and 52.2, which are offset in the longitudinal direction of the measuring tube 1 and are configured to exclude the fixing body of the fixing device arranged in the receiving unit. Starting from the supports 52.1 and 52.2, pressing surfaces 55 extend in the mounting direction. The pressing surfaces 55 have a normal vector formed by the sum of two base vectors (i.e., a first base vector pointing in the mounting direction (see arrow) and a second base vector perpendicular to the first base vector and oriented parallel to the second longitudinal axis 6.2). The pressing surfaces 55 are used to convert the linear mounting movement of the measuring tube 1 in the mounting direction into linear movement of the fixing body in the direction inside the housing. The fixing body is uniformly displaced into the housing by the pressing surfaces 55. After the pressing surfaces are overcome, the spring of the fixing device moves the fixing body in the direction of the supports 52. The supports 52 are formed to be complementary to a section of the fixing body. In the illustrated embodiment, a guide surface 32 is provided between the bracket 52 and the pressing surface 55. This guide surface is inclined relative to the pressing surface 55 and shaped such that, when there is a tension force on the measuring tube opposite to the installation direction, the fixing body is guided out of the bracket 52, thereby releasing the form-locking and / or friction-locking connection between the measuring tube 1 and the receiving unit. According to this embodiment, an additional unlocking device is not required. A longitudinal plane of the measuring tube body, oriented perpendicular to the electrode axis 21, separates the brackets 52.1 and 52.2 on both sides. The longitudinal plane is not a mirror surface because only one side of the two sides has the guide surface 32. The opposite sides have a stop surface whose normal vector points substantially exactly in the installation direction.

[0104] The measuring tube 2 is formed as a single piece and produced by injection molding.

[0105] Figure 11 A cross-section through another embodiment of the measuring tube 1 and receiving unit 22 in an assembled (left) and installed (right) state is shown. Terminal contacts are not shown for clarity. Arranged within the housing 23 of the receiving unit 22 is a magnetic field generating device 25, which includes two coils 26 arranged radially opposite to each other on the measuring tube support 24. Each coil includes coil cores 27.1 and 27.2. The ends of the coil cores 27.1 and 27.2 facing away from the measuring tube support 24 are interconnected via exactly one first field guide 49. Furthermore, the magnetic field generating device 25 has two contact surfaces 50.1 and 50.2 extending from the end face 51 of the housing 23 and contactable by the field guiding component of the measuring tube 1.

[0106] The measuring tube 1 has two radially opposed measuring electrodes that intersect with the electrode axis 21. Furthermore, two radially opposed pole shoes are integrally formed within the measuring tube body 2. A longitudinal plane 41 extends perpendicular to the electrode axis 21, with the longitudinal axis of the measuring tube located within the longitudinal plane 41. The longitudinal plane 41 divides the measuring tube 1 into two parts, I and II. Part I of the measuring tube 1 has a second field guide 42, which is at least partially integrally formed within the measuring tube body 2 and has a first contact surface 43.1 and a second contact surface 43.2. Each contact surface is designed such that when the measuring tube 1 is inserted into the measuring tube support 24, each contact surface is exposed and used to form contact with the contact surfaces 50.1 and 50.2 of the magnetic field generating device 25. The second field guide 42 can be formed secondary by injection molding, thereby connecting the second field guide 42 to the measuring tube body 2 in a form-locking manner.

[0107] In the installed state, the second field guide 42 contacts the contact surfaces 50.1 and 50.2 of the magnetic field generating device 25, and the generated magnetic field passes through the two field guides 42 and 49 around the measuring section of the measuring tube, guiding it from the coil core 27.1 to the opposite coil core 27.2.

[0108] List of reference numerals

[0109] 1 Measuring tube

[0110] 2. Measuring the tube body

[0111] 3. Measuring electrodes

[0112] 3.1 First measuring electrode

[0113] 3.2 Second measuring electrode

[0114] 4 brackets

[0115] 5.1 First Area

[0116] 5.2 Second Region

[0117] 6.1 First longitudinal axis

[0118] 6.2 Second longitudinal axis

[0119] 7. Measure the longitudinal axis of the tube.

[0120] 8. Longitudinal Plane

[0121] 9. Measuring electrode body

[0122] 10. Measuring Electrode Section

[0123] 10.1 First Measuring Electrode Section

[0124] 10.2 Second Measuring Electrode Section

[0125] 11 Front region of the first measuring electrode section

[0126] 12 End region of the first measuring electrode section

[0127] 13. Support in the end region of the first measuring electrode section

[0128] 14 Front region of the second measuring electrode section

[0129] 15. End region of the second measuring electrode

[0130] 16. Support in the end region of the second measuring electrode section

[0131] 17 Temperature sensor

[0132] 18.1 First cross-sectional plane

[0133] 18.2 Second transverse plane

[0134] 19 Plug Connector

[0135] 20. Reference axis of the temperature sensor

[0136] 21 Electrode axis

[0137] 22 Receiving Unit

[0138] 23. Shell

[0139] 24 Measuring tube support

[0140] 25. Magnetic field generating device

[0141] 26 coils

[0142] 27 coil cores

[0143] 28. Connecting contact points

[0144] 28.1 First terminal contact

[0145] 28.2 Second terminal contact

[0146] 28.3 Third terminal contact

[0147] 29 Contact Area

[0148] 30 Measurement Circuit

[0149] 31 Base surface

[0150] 32 Guiding Surface

[0151] 33 Reference Electrode

[0152] 34 supports

[0153] 35 Extreme Boots

[0154] 36 First end face

[0155] 37 Second end face

[0156] 38 First side view

[0157] 39 Second side view

[0158] 40 base surfaces

[0159] 41. Longitudinal Plane

[0160] 42 Second Guiding Body

[0161] 43 Contact Surface

[0162] 44 Operating Circuit

[0163] 45 Opening

[0164] 46 outrigger surfaces

[0165] 47. Measuring tube support base surface

[0166] 48 coil core segments

[0167] 49 First Guiding Body

[0168] 50 Contact Surface

[0169] 51 Front

[0170] 52 brackets

[0171] 53 Fixed body

[0172] 54 Fixing device

[0173] 55. Pressing surface of the measuring tube

[0174] 56 Opening

[0175] 57 Inner Surface

[0176] 58 Magnetic Induction Flow Meter

[0177] 59 Pressing surface of the fixing body

[0178] 60 Process connection section

Claims

1. A measuring tube (1) for conducting a flowable medium in a longitudinal direction, comprising: - a measuring tube body (2), wherein the measuring tube body (2) has an integrated holder (34), wherein the measuring tube body (2) has a mounting surface for mounting the measuring tube (1) in a receiving unit (22) in a mechanically detachable manner; - at least two measuring electrodes (3) for making galvanic contact with the medium; and - at least one pole shoe (35), which is formed from a single sheet metal part or from a plurality of sheet metal parts, wherein the pole shoe (35) is arranged in the holder (34), wherein the measuring tube body (2) is monolithic, wherein the measuring tube body (2) is formed by a one-shot forming method, wherein the pole shoe (35) is partially overmoulded by the one-shot forming method, partially from the encapsulating material with which the measuring tube body (2) is formed, wherein a longitudinal plane (41) divides the measuring tube body (2) into two sides (I, II), wherein a longitudinal axis (7) of the measuring tube (1) extends in the longitudinal plane (41) and the longitudinal plane (41) extends perpendicular to an electrode axis (21) connecting two measuring electrodes (3.1, 3.2), wherein the measuring tube (1) comprises one second field guide (42) for guiding a magnetic field, which is arranged on one of the two sides (I, II) of the measuring tube body (2), wherein the second field guide (42) is connected to the measuring tube body (2) in a form-locked manner, wherein the second field guide (42) has at least one open contact surface (43.1, 43.2), wherein the second field guide (42) is configured to connect two coil cores (27.1, 27.2) of a magnetic field generating device (25) to each other after arranging the measuring tube (1) in a receiving unit (22).

2. The measuring tube (1) according to claim 1, wherein the measuring tube body (2) is mounted in a position defined by the mounting surface.

3. The measuring tube (1) according to claim 1, wherein the pole shoe (35) has a first end face (36) and a second end face (37), which delimit the pole shoe (35) in the longitudinal direction, wherein the measuring tube body (2) extends along the first end face (36) and the second end face (37).

4. The measuring tube (1) according to claim 3, wherein, the measuring tube body (2) completely covers the first end face and the second end face, respectively, in the longitudinal direction.

5. The measuring tube (1) according to claim 3, wherein, the pole shoe (35) has a first side face (38) and a second side face (39), wherein the first side face (38) connects the first end face (36) to the second end face (37), wherein the second side face (39) connects the first end face (36) to the second end face (37), wherein the measuring tube body (2) extends along the first side (38) and the second side (39).

6. Measuring tube (1) according to claim 5, wherein the measuring tube body (2) completely covers the first side and the second side.

7. Measuring tube (1) according to claim 5, wherein, the base surface (40) of the pole piece (35) is not covered or only partially covered by the measuring tube body (2), wherein the base surface (40) connects the first end surface (36) and the second end surface (37), wherein the base surface (40) connects the first side (38) with the second side (39).

8. Measuring tube (1) according to claim 1 or 3, wherein the measuring tube body (2) is formed by an injection molding method.

9. Measuring tube (1) according to claim 8, wherein, the second field guide (42) has two open contact surfaces (43.1, 43.2).

10. Measuring tube (1) according to claim 1, wherein the measuring tube body (2) is designed to be electrically insulating.

11. Measuring tube (1) according to claim 1, wherein the at least two measuring electrodes (3) are arranged diametrically opposite in the measuring tube body (2).

12. Measuring tube (1) according to claim 1, wherein the plurality of sheet metal parts are stacked and connected to each other in the longitudinal direction of the pole piece.

13. Receiving unit (22) for receiving an exchangeable measuring tube (1), the measuring tube being a measuring tube (1) according to any one of the preceding claims, the receiving unit (22) comprising: - a housing (23), wherein the housing (23) has a measuring tube holder (24); - a magnetic field generating device (25) for generating a magnetic field extending through the measuring tube (1), wherein the magnetic field generating device (25) comprises a coil (26) and a coil core (27), wherein the magnetic field generating device (25) is arranged in the housing (23); - a measuring circuit (30) for determining a measuring voltage applied to a measuring electrode (3) of the measuring tube (1); - an operating circuit (44) for operating the magnetic field generating device; - at least two terminal contacts (28) designed for electrically and mechanically detachably connecting a measuring electrode (3) of the measuring tube (1) to the measuring circuit (30), wherein a contact area (29) of the respective terminal contact (28) protrudes from the housing (23) and extends into the measuring tube holder (24), wherein the coil core (27) extends through an opening (45) in the measuring tube holder (24), wherein the coil core (27) is designed and arranged in the measuring tube holder (24) such that, when the measuring tube (1) is arranged in the measuring tube holder (24), contact is produced between the coil core (27) and the pole piece (35), wherein the magnetic field generating device (25) has two coils (26.1, 26.2), each coil having a coil core (27.1, 27.2) extending through the interior of the coil (26.1, 26.2), wherein the connection of the two coil cores (27.1, 27.2) is effected via a first field guide (49), wherein the magnetic field generating device (25) has two contact surfaces (50.1, 50.2), each contact surface serving as a contact surface (50.1, 50.2) of a second field guide (42) arranged on the measuring tube (1), wherein the contact surfaces (50.1, 50.2) are arranged on an end face (51) of the housing (23).

14. The receiving unit (22) of claim 13, wherein the measuring tube support (24) being bounded in a direction perpendicular to the installation direction of the measuring tube (1) and perpendicular to the longitudinal direction of the measuring tube body (2) by two leg surfaces (46.1, 46.2), wherein the measuring tube support (24) is bounded in the installation direction of the measuring tube (1) by a measuring tube support base surface (47).

15. The receiving unit (22) of claim 14, wherein the coil (26) being arranged in the installation direction in the housing (23) behind the measuring tube support base surface (47), wherein the coil core (27) has a first coil core section (48.1) extending through the coil (26), wherein the coil core (27) has a second coil core section (48.2) extending in the direction of one of the two leg surfaces (46.1, 46.2) from the first coil core section (48.1).

16. Magnetic inductive flowmeter (58), comprising: - a receiving unit (22) according to any one of claims 13 to 15, - a measuring tube (1) for conducting a flowable medium in a flow direction, the measuring tube being according to any one of claims 1 to 12, wherein the measuring tube (1) is connected to the receiving unit (22) in a mechanically detachable manner, wherein a magnetic field generating device (25) arranged in a housing (23) of the receiving unit (22) has two coils (26.1, 26.2), wherein the two coils (26.1, 26.2) each have at least one coil core (27.1, 27.2) extending through the respective coil (26.1, 26.2), wherein a second field guide (42) of the measuring tube (1) connects the two coil cores (27.1, 27.2) to one another.

17. The magnetic inductive flowmeter (58) of claim 16, wherein, A pole piece (35) arranged on the measuring tube (1) is in contact with a coil core (27) extending through an opening (45) in the measuring tube support (24).

18. The magnetic induction flow meter (58) of claim 16, wherein, The measuring tube (1) is connected to the receiving unit (22) in a friction-locked and / or form-locked manner.

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