MAGNETIC CIRCUIT DEVICE FOR A MAGNETIC-INDUCTIVE FLOWMETER AND METHOD FOR MANUFACTURING A MAGNETIC CIRCUIT DEVICE

Abstract

A magnetic circuit device (1) for a magnetic-inductive flowmeter, having a coil (2) that has a coil core (3). The magnetic circuit device (1) enables an increased range of application, in that it can be flexibly adapted to the geometries of the respective magnetic flow meter due to the fact that the coil core (3) is designed to be flexible in such a way that the coil (2) can be bent from a first shape into a second shape. In addition, a method (100) for manufacturing such a magnetic circuit device (1) involves the steps of provisioning, winding, heating, connecting, bending and fixing of the coil.

Claims

1. A magnetic circuit device for a magnetic-inductive flowmeter, comprising: a coil arrangement comprising a coil and a coil core arranged in the coil, wherein the coil core is flexible, such that the coil arrangement is bendable from a first shape into a second shape.

2. The magnetic circuit device according to claim 1, wherein the coil core is springily configured, and wherein the coil core in its second shape is in a relaxed state and can be brought into a preloaded state.

3. The magnetic circuit device according to claim 1, wherein the coil core is made of a nickel-iron alloy or of a soft iron composition.

4. The magnetic circuit device according to claim 1, wherein the coil core has a length L which is greater than eight times the diameter D of the coil core.

5. The magnetic circuit device according to claim 4, wherein the coil is orthocyclically wound.

6. The magnetic circuit device according to claim 1, wherein the coil is an insulated coil wire, and wherein the insulation of the coil wire has been at least partially melted by heating after the coil has been wound in such a way that the coil has a flexibility which is increased relative to the flexibility of the coil prior to heating.

7. The magnetic circuit device according to claim 1, further comprising two pole plates and wherein the coil core is connected at least indirectly to the pole plates or wherein the coil core is connected directly to the pole plates by ends of the coil core having been welded to the pole plates.

8. A coil arrangement for a magnetic circuit device for a magnetic-inductive flow meter, comprising a coil and a coil core arranged in the coil, the coil core being flexible such that the coil arrangement is bendable from a first shape into a second shape.

9. The coil arrangement according to claim 8, wherein the coil has at least one of: a springy configuration, and wherein the coil core in its second shape is in a relaxed state and can be brought into a preloaded state, a nickel-iron alloy, or soft iron composition, a length L which is greater than eight times the diameter D of the coil core, or an insulated coil wire, the insulation of which has been at least partially melted by heating after the coil has been wound in such a way that the coil has a flexibility which is increased relative to the flexibility of the coil prior to heating.

10. A method for manufacturing a magnetic circuit device for a magnetic-inductive flowmeter, wherein the magnetic circuit device comprises a coil with a coil core and two pole plates, the method comprising: providing a flexible coil core in a provisioning step, winding N windings of insulated coil wire around the coil core, and connecting the coil core to the pole plates.

11. The method according to claim 10, comprising the further step of heating the coil such that the insulation of the coil wire at least partially melts.

12. The method according to claim 11, wherein the heating is implemented by passing a current through the coil wire or by inductive heating.

13. The method according to claim 10, comprising the further step of bending the magnetic circuit device from a first shape into a second shape.

14. The method according to claim 13, comprising the further step of fixing ends of the coil core in a final shape by a fixing means.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG. 1 shows a first embodiment of a magnetic circuit device,

[0029] FIG. 2a shows a second magnetic circuit device in a first shape,

[0030] FIG. 2b shows the magnetic circuit device from FIG. 2a in a second shape,

[0031] FIG. 3 shows a third embodiment of a magnetic circuit device,

[0032] FIG. 4 is a schematic diagram of a coil of a magnetic circuit device,

[0033] FIG. 5 is a block diagram of a first method of mounting a magnetic circuit device; and

[0034] FIG. 6 is a block diagram of a second method of mounting a magnetic circuit device.

DETAILED DESCRIPTION OF THE INVENTION

[0035] FIG. 1 shows a magnetic circuit device 1 for a magnetic-inductive flowmeter, which itself is not shown. The magnetic circuit device 1 has a coil 2. The coil 2 is made of windings of insulated copper wire wound around a coil core 3. The coil core 3 arranged in the coil 2 is flexibly designed in such a way that the coil arrangement comprised of coil 2 and coil core 3 can be bent from a first shape into a second shape. In the embodiment shown, the coil core is made of a nickel-iron alloy. Nickel-iron alloys are very soft metal alloys which facilitate bending of the coil core 3. When choosing the material of the coil core 3, it is important that the material is not destroyed during bending, for example, that it breaks. In addition, the nickel-iron alloy used has a high permeability and is therefore particularly suitable as material for coil core 3.

[0036] In FIGS. 2a and 2b a magnetic circuit device 1 is shown, wherein, in the illustration of FIG. 2a, the coil arrangement of the coil 2 and the coil core 3 is bent in a first shape and, in FIG. 2b, the coil arrangement of the coil 2 and the coil core 3 is bent in a second shape. In FIG. 2a, the coil extends along its longitudinal axis, wherein the longitudinal axis corresponds to the coil axis. In FIG. 2b, the coil arrangement is bent into a U-shape. This is possible due to the flexibility of the coil core 3. In the embodiment shown, the coil core 3 has such flexibility that the coil arrangement consisting of the coil 2 and the coil core 3 can be bent (plastically deformed) from one shape into another shape, but remains in the shape after the bending process.

[0037] To implement a long coil 2, the coil core 3 has a length L which is at least eight times the thickness D of the coil core. The coil core 3 is wound with a coil wire 4, wherein the coil wire 4 has a thickness d. A cross-section through a wound coil 2 is shown in FIG. 3. Here, the coil core 3 is shown with its thickness D and length L, which is wound with coil wire 4. The coil wire 4 has an insulation 5, which is only shown very schematically in a single coil wire cross-section for reasons of clarity.

[0038] The coil 2 is orthocyclically wound so that a maximum fill factor is achieved. In orthocyclic winding, the windings of one winding layer 6 are located in the valleys of the previous winding layer 7. The coil shown in FIG. 3 has 10 winding layers. One winding position has 100 windings, so that the coil shown has a total of 1000 windings. For the sake of clarity, only part of the 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 wire 4 has a thickness d of 0.2 mm With such a design, the coil wire 4 has a corresponding approximate length of 14 m. This is a particularly elegant way of creating a thin, long coil with a minimal stray field and minimal energy loss.

[0040] After winding, the coil 2 is warmed by heating, which at least partially melts the insulation 5. Thus the flexibility of the coil 2 is increased. After the coil 2 is thus cooled down again, it has a higher flexibility than before the heating process.

[0041] As can be seen in FIGS. 1, 2a, 2b and 4, the magnetic circuit device 1 has two pole plates 4 just like the coil arrangement. The magnetic field B of the coil 2 is created between the pole plates 8. The measuring tube 9 of the magnetic-inductive flow meter is arranged between the pole plates 8, as shown in FIG. 4. The electrically conductive medium to be measured flows through the measuring tube 9. The measuring tube 9 is also used as a fixing means 10 to fix the bent coil arrangement in its final shape.

[0042] The coil core 3 of the coil 2 is directly connected to the pole plates 8 in the configurations shown. This is achieved by welding the ends 11 of the coil core 3 to the pole plates 8.

[0043] FIG. 5 shows a block diagram of a method 100 for manufacturing a magnetic circuit device 1. In a provisioning step 101, a flexible coil core is provided. When a flexible coil core is mentioned, it is a coil core which is made of a flexible material and has a geometry which allows the coil core to be bent. In a winding step 102 following the provisioning step 101, N windings of insulated coil wire are wound around the coil core. In a heating step 103, the coil is heated in such a way that the insulation of the coil wire at least partially melts. This increases the flexibility of the cooled coil. In the illustrated version of the method 100, the heating step 103 is achieved by passing a current through the coil. The type of heating step 103 is marked with the reference symbol 103′. In a connecting step 104, the coil core is connected to the pole plates. This is implemented in the present case by welding the ends of the coil core to the pole plates. In addition, the connecting step 104 is followed by a bending step 105, in which the coil arrangement or the magnetic circuit device is bent into a final shape.

[0044] A variation of the method 100 is shown in FIG. 6. The method shown here differs in that the heating step is implemented by inductive heating, which is illustrated by the reference symbol 103″. In addition, the bending step 105 is carried out before the connecting step 104. In a final fixing step 106, the ends of the coil core are fixed in their final shape by means of a fixing means. This prevents the bent magnetic circuit device from being unintentionally bent into a different shape, which could possibly change the magnetic field that is formed.

REFERENCE NUMBERS

[0045] 1 Magnetic circuit device [0046] 2 Coil [0047] 3 Coil core [0048] 4 Coil wire [0049] 5 Insulation [0050] 6 Winding layer [0051] 7 Winding layer on the previous winding layer 6 [0052] 8 Pole plates [0053] 9 Measuring tube [0054] 10 Fixing means [0055] 11 Ends of the coil core [0056] 100 Method [0057] 101 Provisioning step [0058] 102 Winding step [0059] 103 Heating step [0060] 103′ Heating step using coil current [0061] 103″ Heating step using inductive heating [0062] 104 Connecting step [0063] 105 Bending step [0064] 106 Fixing step