Magnetic circuit arrangement for a flowmeter of the magnetic-inductive type and method for processing a magnetic circuit arrangement
By using flexible coil cores and heat-treated coil wires, the shape adaptation problem of magnetic circuit equipment is solved, enabling wider applications and more efficient magnetic field homogeneity, and simplifying the assembly process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- KROHNE AG
- Filing Date
- 2021-05-26
- Publication Date
- 2026-05-12
AI Technical Summary
The geometric design of existing magnetic circuit devices limits their application possibilities and makes them difficult to deform after processing, resulting in easy damage during assembly and transportation.
The coil core is made of flexible material. The insulation of the coil wire is partially melted by heating to improve flexibility. The coil device is made flexible by orthogonal cyclic winding and direct or indirect connection of the pole plates.
It expands the application range of magnetic circuit equipment, simplifies the assembly process, improves the homogeneity and anti-interference ability of the magnetic field, and reduces energy loss.
Smart Images
Figure CN113720405B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a magnetic circuit device for a magnetically inductive flow meter, comprising a coil and a coil core arranged within the coil. Furthermore, this invention relates to a coil arrangement for a magnetic circuit device. Additionally, this invention relates to a method for manufacturing a magnetic circuit device. Background Technology
[0002] Various magnetic circuit devices are known from the prior art and are used to generate homogeneous magnetic fields. Magnetic fields are necessary for the measurement of magnetically induced flow rates because the measurement principle is based on the charge separation of charges moving in the magnetic field.
[0003] The magnetic circuit device has at least one coil that generates a magnetic field. A coil core is often arranged within the coil. The generated magnetic field is mostly guided to pole shoes by magnetic field guiding elements. The pole shoes are used to allow the magnetic field lines to escape from the magnetic circuit in a prescribed manner and manner; the magnetic field passes through the space between the pole shoes. Preferably, in the case of a magnetically inductive flow meter, the pole shoes are implemented by pole shoe plates having a relatively small thickness, which will be discussed below. However, the invention can also be transferred to other forms of pole shoes.
[0004] For example, a magnetic circuit device for a magnetically inductive flow meter is known from EP 2 479 541 A1. This magnetic circuit device has a coil and two pole plates, wherein the coil is directly connected to one pole plate and connected to a second pole plate via two curved connecting elements. Therefore, the magnetic circuit device has a generally annular outer contour. A disadvantage of the magnetic circuit device known in the prior art is that its application possibilities are limited by its geometric design.
[0005] Magnetic circuit devices for magnetically inductive flow meters are also known from DE 10 2017 131 202 A1 and DE 10 2018 125 865 A1. The magnetic circuit device has a coil and a coil core, wherein the coil core is implemented by a plate element. In machining the magnetic circuit device, the plate element is bent into a corresponding shape and held in its position. The bent magnetic circuit device is then released for assembly of the entire magnetically inductive flow meter, wherein the magnetic circuit device itself remains in its shape during assembly. A disadvantage here is that the magnetic circuit device cannot be used variably because its dimensions are determined by machining the device. That is, the magnetic circuit device is machined, for example, for a predetermined size of the measuring tube. Furthermore, the material for the magnetic circuit device is selected such that it cannot be bent without force after machining the device. This prevents damage to the magnetic circuit device, for example, during transport. Summary of the Invention
[0006] The objective of this invention is to provide a magnetic circuit device and a coil arrangement for the magnetic circuit device, which enable an expanded range of applications, and in particular, which can be flexibly adapted to the geometry of a corresponding magnetically inductive flow meter.
[0007] In this invention, the task is addressed primarily and substantially by the following feature: flexibly designing the coil core so that the coil assembly can be bent from a first shape to a second shape.
[0008] When referring to the flexible design of the coil core, it therefore means that the coil core is made of a bendable material. Here, bendability means that the material is selected not only according to its strength and size but also according to its material properties so that it can be bent, thus achieving a flexible coil core. Specifically, it should be understood that the coil assembly can also be bent effortlessly after its processing. The coil assembly is specifically designed to be bent when assembled into a magnetically inductive flow meter and to fit the dimensions of the magnetically inductive flow meter. Accordingly, not every arbitrary material is suitable for manufacturing the coil core. In particular, the material must not be brittle, because otherwise the coil core would break when bent. The material must be selected so that it can be bent freely and frequently without damage from a first shape to a second shape.
[0009] According to the present invention, it has been recognized that the use of flexible coil cores significantly improves the application and usability of magnetic circuit devices. In particular, the assembly of complete magnetically inductive flow meters can be significantly simplified when the magnetic circuit device can be bent from one shape to another due to the flexible, bendable coil.
[0010] In a particularly preferred design, the coil core is flexibly designed. Thus, the coil core can not only bend from a first shape to a second shape. More precisely, the coil core is in a relaxed state in its second shape and can further reach a pre-tightened state. Preferably, the coil core can be fixed or held in the pre-tightened state. Upon removal of the fixation or support, the coil core returns to its relaxed state.
[0011] According to the present invention, it has been recognized that soft materials are particularly suitable as materials for coil cores. In a very particularly preferred embodiment, the coil core is made of a nickel-iron alloy. In a very particularly preferred embodiment, the coil core is made of a nickel-iron alloy having 50 percent nickel and 50 percent iron. However, the invention is not limited to this composition. In other preferred embodiments, the iron content is greater than 50 percent or less than 50 percent.
[0012] In another design, the coil core is made of soft iron.
[0013] Besides the type of material of the coil core, the size or geometry of the coil core is also very important to the present invention. In a particularly preferred variant, the coil core has a length greater than eight times the diameter of the coil core. With such a coil core, a so-called long coil can be achieved during the corresponding winding. A long coil is understood to be a coil whose length is significantly greater than its diameter. In particular, it is preferred to be a coil whose length corresponds to at least eight times its diameter. Compared to a short coil whose length is on the same order of magnitude as the coil radius, a long coil has the advantage that the magnetic field inside the coil is homogeneous, or significantly more homogeneous than the magnetic field inside a short coil. Furthermore, significantly less unwanted scattered field occurs in a long coil. Thus, energy loss caused by scattered field can be minimized. In addition, by using a long coil, susceptibility to scattered field interference can be reduced. Due to the significantly less scattered field, it is possible to simplify shielding measures for shielding scattered field, or to abandon the use of shielding measures for shielding scattered field.
[0014] In a very particularly preferred design, the coil core has a diameter of 2.5 mm and a length of 20 mm. More preferably, the coil core is implemented using a wire with a preferably circular cross-section.
[0015] To achieve the highest possible filling efficiency during coil winding, a specific design of the magnetic circuit device according to the invention specifies that the coil is wound in an orthogonal loop. The orthogonal loop winding is characterized by arranging the turns of the upper winding layer within the valleys of the lower winding layer.
[0016] In a preferred variation, the coil is made of insulated coil wire. Particularly preferred is that the coil is made of insulated copper wire. Copper wire is characterized by its very good conductivity.
[0017] According to the present invention, it has been recognized that the flexibility of the coil assembly is further improved by melting the insulation of the coil wire by heating, at least partially, after the coil is wound. After cooling, the coil assembly has increased flexibility compared to before heating. This is achieved by heating the insulated wire, which destroys a portion of the insulation, thereby reducing the insulation layer thickness.
[0018] As explained at the beginning, magnetic circuit devices typically have two pole plates, between which a magnetic field is constructed. In a particularly preferred design, a flexible coil core is connected to the pole plates at least indirectly. When referring to the connection of the coil core at least indirectly to the pole plates, a yoke element that guides the magnetic field generated by the coil can be specifically provided, connecting the coil core to the pole shoes. However, in order not to reduce the flexibility of the magnetic circuit device due to a particularly rigid yoke element, a very particularly preferred variant specifies that the coil core is directly connected to the pole plates. This connection can be achieved, for example, by welding the ends of the coil core to the pole plates. However, other connection techniques known from the prior art are also suitable. In this type of design, only the pole plates are rigidly constructed. The connection between the two pole plates is flexibly achieved solely through the coil or coil core, so that bending of the coil can cause the two pole plates to be arranged in a large number of opposing configurations.
[0019] Besides magnetic circuit devices, the present invention also relates to a coil arrangement for a magnetically inductive flow meter, the coil arrangement having a coil and a coil core arranged in the coil. In the case of the coil arrangement, the objective of the present invention is achieved by flexibly designing the coil core so that the coil arrangement can bend from a first shape to a second shape. All the preferred designs of the coil arrangement described in the magnetic circuit device aspect according to the invention are correspondingly applicable to the preferred designs of the coil arrangement according to the invention.
[0020] Furthermore, the present invention relates to a method for manufacturing a magnetic circuit device for a magnetically inductive flow meter, wherein the magnetic circuit device has a coil with a coil core and two pole plates. The method according to the invention is characterized in that: in a preparation step, a coil core made of a flexible material is provided; in a winding step, N turns of insulated coil wire are wound around the coil core; and in a connection step, the coil core is connected to the pole plates.
[0021] According to the present invention, it has been recognized that a magnetic circuit device can be flexibly realized by providing a flexible coil core. This results in the coil of the magnetic circuit device being able to bend from a first shape to a second shape. Even thereafter, the corresponding magnetic circuit device can be optimally adapted to the given conditions of the geometry of a magnetically inductive flow meter.
[0022] In a particularly preferred improvement, the coil is heated in the heating step to at least partially melt the insulation of the coil wires. It has been recognized that the heating step can further improve the flexibility of the coil of the magnetic circuit device, and therefore the flexibility of the magnetic circuit device itself.
[0023] The heating step can be implemented in different methods and ways. In a preferred variation, the heating step is achieved by guiding current through the coil wires. The current intensity is chosen such that the insulation of the coil wires is at least partially melted by heating.
[0024] In an alternative variant, the heating step is achieved through induction heating.
[0025] An improved version of the method according to the invention is characterized in that, in an additional bending step, the magnetic circuit device is bent from a first shape to a second shape. Preferably, the additional bending step is performed after the connection step. In an alternative variation, the bending step is performed before the connection step, that is, before the coil core is at least indirectly connected to the pole shoe plate.
[0026] In another method step, in another embodiment of the method according to the invention, the magnetic circuit device is fixed in the final shape during a fixing step. Fixing aids are used for this purpose. Specifically, in the fixing step, the ends of the coil core are fixed in the final shape. This variation has the advantage that the magnetic circuit device can no longer be accidentally bent when it is bent into the final shape in one go. In the final shape of the magnetic circuit device, the magnetic field preferably has the maximum possible homogeneity and the desired magnetic field strength. Attached Figure Description
[0027] Specifically, there are numerous feasibility studies for designing and improving the magnetic circuit device, the coil, and the method according to the invention. Among them:
[0028] Figure 1 The first design scheme of the magnetic circuit device is shown.
[0029] Figure 2 a shows a second magnetic circuit device in the first shape.
[0030] Figure 2 b shows from Figure 2 The magnetic circuit device of a in the second shape.
[0031] Figure 3 The third design scheme of the magnetic circuit device is shown.
[0032] Figure 4 A schematic diagram of the coil of a magnetic circuit device is shown.
[0033] Figure 5 A block diagram of a first method for assembling a magnetic circuit device is shown, and
[0034] Figure 6 A block diagram of a second method for assembling magnetic circuit devices is shown. Detailed Implementation
[0035] Figure 1 A magnetic circuit device 1 for a magnetically inductive flow meter is shown, the flow meter itself not shown. The magnetic circuit device 1 has a coil 2. The coil 2 is made of insulated copper wire by turns of wire wound around a coil core 3. The coil core 3 is flexibly designed and arranged within the coil 2 so that the coil assembly consisting of the coil 2 and the coil core 3 can be bent from a first shape to a second shape. In the illustrated design, the coil core is made of a nickel-iron alloy. Nickel-iron alloys are very soft metal alloys, which simplify the bending of the coil core 3. It is important in selecting the material for the coil core 3 that the material will not be damaged, for example, broken, when bent. Furthermore, the nickel-iron alloy used has high magnetic permeability and is therefore particularly suitable as a material for the coil core 3.
[0036] exist Figure 2 a and Figure 2 Figure b shows magnetic circuit device 1, in which... Figure 2 In the diagram of a, the coil assembly made of coil 2 and coil core 3 is bent in the first shape, and... Figure 2 In step b, the coil assembly made of coil 2 and coil core 3 is bent in the second shape. Figure 2 In a, the coil extends along its longitudinal axis, wherein the longitudinal axis corresponds to the coil axis. Figure 2 In embodiment b, the coil assembly is U-shaped. This bending is feasible due to the flexibility of the coil core 3. In the illustrated embodiment, the coil core 3 has such flexibility that the coil assembly made of the coil 2 and the coil core 3, while able to bend from one shape to another, remains in that shape after the bending process.
[0037] To achieve a long coil 2, the coil core 3 has a length L corresponding to at least eight times the thickness D of the coil core. The coil core 3 is wound with coil wire 4, wherein the coil wire 4 has a thickness d. Figure 3 The image shows a cross-section of the wound coil 2. Here, the coil core 3, having a thickness D and a length L, is readily apparent, and is wound around the coil wire 4. The coil wire 4 has an insulating portion 5, which, for clarity, is shown only schematically in a single coil wire cross-section.
[0038] The coil 2 is wound in an orthogonal loop to achieve maximum filling efficiency. During the orthogonal loop winding, the turns of the coil layer 6 are placed into the valleys of the preceding coil layer 7. Figure 3 The coil shown has 10 layers of coil turns. Each layer has 100 coil turns, so the coil shown has a total of 1000 coil turns. For clarity, only a portion of coil 2 is shown.
[0039] The coil core has a thickness D of 2.5 mm and a length L of 20 mm. The coil conductor 4 has a thickness d of 0.2 mm. In this design, the coil conductor 4 correspondingly has a length of approximately 14 m. Therefore, a thin, long coil with minimal scattering field and minimal energy loss can be achieved in a particularly ingenious way.
[0040] After winding, the temperature of the coil 2 is increased by heating, thereby at least partially melting the insulation portion 5. This improves the flexibility of the coil 2. After cooling the coil 2 again, the coil has greater flexibility than before the heating process.
[0041] As in Figure 1 , Figure 2 a, Figure 2 b and Figure 4 As can be seen, in addition to the coil assembly, the magnetic circuit device 1 also has two pole plates 4. The magnetic field B of the coil 2 is constructed between the pole plates 8. (As shown in...) Figure 4 As shown, a measuring tube 9 of a magnetically inductive flow meter is arranged between the electrode plates 8. The conductive medium to be measured flows through the measuring tube 9. Additionally, the measuring tube 9 serves as a fixing auxiliary device 10 to secure the bent coil assembly in its final shape.
[0042] In the illustrated design, the coil core 3 of the coil 2 is directly connected to the pole plate 8. This connection is achieved by welding the end 11 of the coil core 3 to the pole plate 8.
[0043] Figure 5A block diagram of a method 100 for processing a magnetic circuit device 1 is shown. In preparation step 101, a flexible coil core is provided. When discussing a flexible coil core, this means that the coil core is made of a bendable material and has a geometry that allows the coil core to bend. In winding step 102, immediately following preparation step 101, N turns of insulated coil wire are wound around the coil core. In heating step 103, the coil is heated such that the insulation of the coil wire is at least partially melted. This increases the flexibility of the coil after recooling. In the illustrated embodiment of method 100, heating step 103 is achieved by guiding current through the coil. The type of heating step 103 is indicated by reference numeral 103'. In connection step 104, the coil core is connected to the pole plate. Here, this connection is achieved by welding the ends of the coil core to the pole plate. Furthermore, bending step 105 follows immediately after connection step 104, in which the coil device or the magnetic circuit device is bent into the final shape.
[0044] exist Figure 6 A variation of method 100 is shown. The method shown here is distinguished by the fact that the heating step is achieved through induction heating, as indicated by reference numeral 103''. Furthermore, a bending step 105 is performed prior to the connecting step 104. In the final fixing step 106, the end of the coil core is fixed to its final shape by means of a fixing aid. This prevents the bent magnetic circuit device from accidentally bending into another shape, thus allowing for modification of the constructed magnetic field if necessary.
[0045] List of reference numerals
[0046] 1. Magnetic circuit equipment
[0047] 2 coils
[0048] 3 coil cores
[0049] 4. Coil wires
[0050] 5. Insulation section
[0051] 6 winding layers
[0052] 7. Winding layer after winding layer 6
[0053] 8 plates
[0054] 9 Measuring tubes
[0055] 10 Fixed auxiliary devices
[0056] 11. End of the coil core
[0057] 100 methods
[0058] 101 Preparation Steps
[0059] 102 Winding Steps
[0060] 103 Heating Steps
[0061] 103' Heating step through coil current
[0062] 103'' Heating steps via induction heating
[0063] 104 Connection Steps
[0064] 105 Bending Steps
[0065] 106 Fixed Steps
Claims
1. A magnetic circuit device (1) for a magnetically inductive flow meter, having a coil device having a coil (2) and a coil core (3) arranged in the coil (2). in, The magnetic circuit device (1) has two pole plates (8), and the coil core (3) is at least indirectly connected to the pole plates (8). Its features are, The coil core (3) is flexibly designed so that the coil assembly can be bent from a first shape to a second shape.
2. The magnetic circuit device (1) according to claim 1, characterized in that, The coil core (3) is designed flexibly, wherein the coil core is in a relaxed state in its second shape and is capable of reaching a pre-tightened state.
3. The magnetic circuit device (1) according to claim 1 or 2, characterized in that, The coil core (3) is made of nickel-iron alloy or of soft iron.
4. The magnetic circuit device (1) according to claim 1 or 2, characterized in that, The coil core (3) has a length L, which is greater than eight times the diameter D of the coil core (3).
5. The magnetic circuit device (1) according to claim 1 or 2, characterized in that, The coil core (3) has a diameter D of 2.5 mm and a length L of 20 mm.
6. The magnetic circuit device (1) according to claim 1 or 2, characterized in that, The coil (2) is wound in an orthogonal loop.
7. The magnetic circuit device (1) according to claim 1 or 2, characterized in that, The coil (2) is made of insulated coil wire (4), wherein, after the coil (2) is wound, the insulation (5) of the coil wire (4) is at least partially melted by heating, so that the flexibility of the coil (2) is improved after heating.
8. The magnetic circuit device (1) according to claim 1 or 2, characterized in that, The coil (2) is made of insulated copper wire.
9. The magnetic circuit device (1) according to claim 1 or 2, characterized in that, The coil core (3) is directly connected to the pole plate (8).
10. The magnetic circuit device (1) according to claim 1 or 2, characterized in that, The end (11) of the coil core (3) is welded to the pole plate (8).
11. A method (100) for fabricating a magnetic circuit device for a magnetically inductive flow meter, wherein, The magnetic circuit device has a coil with a coil core and two pole plates (8). Its features are, In preparation step (101), a flexible coil core is provided. In the winding step (102), N turns of insulated coil wire are wound around the coil core, and In the connection step (104), the coil core is connected to the electrode plate.
12. The method (100) according to claim 11, characterized in that, In the heating step (103), the coil is heated such that the insulation of the coil wire is at least partially melted.
13. The method (100) according to claim 12, characterized in that, The heating step (103) is achieved by guiding current through the coil wire (103') or by induction heating (103'').
14. The method (100) according to any one of claims 11 to 13, characterized in that, In the additional bending step (105), the magnetic circuit device is bent from the first shape to the second shape.
15. The method (100) according to any one of claims 11 to 13, characterized in that, In the fixing step (106), the magnetic circuit device is fixed in the final shape by fixing auxiliary devices.
16. The method (100) according to any one of claims 11 to 13, characterized in that, In the fixing step (106), the end of the coil core is fixed in the final shape by a fixing auxiliary device.