阅读说明：本技术 磁感应式流量测量仪和磁路装置 (Magnetic induction type flow measuring instrument and magnetic circuit device ) 是由 J·C·冈萨雷斯-佩莱约 C·保罗 J·内文 于 2020-09-03 设计创作，主要内容包括：本发明涉及一种磁感应式流量测量仪,带有用于导引能导电的介质的测量管,带有在测量管外延伸的、用于产生和用于导引至少部分垂直于介质的流动方向地贯穿测量管的磁场的磁路装置,并且带有用于对在介质中感应出的测量电压分压的两个电极(4),本发明所要解决的任务是,说明一种磁感应式流量测量仪,所述磁感应式流量测量仪的出色之处在于改进的测量灵敏度,由此来解决所述任务,即,每个极靴板具有面朝第一线圈的第一侧面和与所述第一侧面对置的第二侧面,并且为了将磁场输入到极靴板中,在极靴板的第一侧面处分别构造有每个极靴板至少两个输入区域。(The invention relates to a magnetic-inductive flow meter with a measuring tube for conducting an electrically conductive medium, with magnetic circuit means extending outside the measuring tube for generating and for guiding a magnetic field which penetrates the measuring tube at least partially perpendicularly to the flow direction of the medium, and having two electrodes (4) for dividing a measurement voltage induced in the medium, the object of the invention is to specify a magnetic-inductive flowmeter, the magnetic-inductive flow meter is distinguished by an improved measurement sensitivity, by means of which the object is solved, i.e. each pole shoe plate has a first side facing the first coil and a second side opposite to the first side, and for the purpose of inputting a magnetic field into the pole shoe plates, at least two input regions per pole shoe plate are formed in each case at the first side of the pole shoe plates.)

1. Magnetic-inductive flow meter (1) having a measuring tube (2) for guiding an electrically conductive medium, having a magnetic circuit arrangement (3) extending outside the measuring tube (2) for generating and for guiding a magnetic field which penetrates the measuring tube (2) at least partially perpendicular to the flow direction of the medium, and having two electrodes (4) for dividing a measuring voltage induced in the medium, wherein the magnetic circuit arrangement (3) has at least one first coil (5) and a first pole shoe (6) and a second pole shoe (7) for generating a magnetic field, wherein the magnetic field is formed between the pole shoes (6, 7), wherein the measuring tube (2) is arranged between the two pole shoes (6, 7), and wherein the electrodes (4) are arranged on mutually opposite sides of the measuring tube (2) and a hypothetical connecting line extends between the two electrodes (4) perpendicular to the flow direction and perpendicular to the magnetic field direction,

it is characterized in that the preparation method is characterized in that,

each pole shoe (6, 7) has a first side (9) facing the first coil (5) and a second side (10) opposite the first side (9), and at least two input regions (11) are formed on each pole shoe (6, 7) on the first side (9) of the pole shoe (6, 7) for the purpose of inputting a magnetic field into the pole shoe (6, 7).

2. The magnetic-inductive flow meter (1) according to claim 1, characterized in that the input regions (11) are each formed in the outer quarter of the longitudinal extent of the first side (9) of the pole shoe plates (6, 7).

3. The magnetic-inductive flow meter (1) according to claim 1 or 2, characterized in that the first coil (5) is arranged on the side of an electrode (4) and is connected to the pole shoes (6, 7) at the input region (11) by means of a respective Y-shaped yoke element (12).

4. The magnetic induction flow meter (1) according to one of claims 1 to 3, characterised in that the magnetic circuit arrangement (3) has a second coil (5), so that the magnetic field running through the measuring tube (2) is generated by two coils (5), the second coil (5) being arranged on the side of the pole shoes (6, 7) opposite the first coil (5), so that the second side (10) of the pole shoes (6, 7) faces the second coil (5), and at least two further input regions (11) per pole shoe (6, 7) being formed in each case on the second side (10) of the pole shoes (6, 7) for the purpose of inputting the magnetic field into the pole shoes (6, 7).

5. The magnetic induction flow meter (1) according to one of claims 1 to 3, characterised in that the magnetic circuit device (3) has a second coil (5), whereby the magnetic field through the measuring tube (2) is generated by two coils (5) and the second coil is arranged on the same side of the pole shoes (6, 7) as the first coil (5).

6. The magnetic induction flow meter (1) according to one of claims 1 to 5, characterised in that the magnetic circuit arrangement (3) has four coils (5), so that the magnetic field running through the measuring tube (2) is generated by the four coils (5), each two coils (5) being arranged one behind the other on the side of the respective one electrode (4) as viewed in the flow direction, and each coil (5) being connected at least indirectly via an input region (11) to the first pole shoe (6) and to the second pole shoe (7), in particular the two coils (5) of each side being arranged parallel to one another, in particular each electrode (4) being arranged between the coils (5) of one side as viewed in the flow direction.

7. The magnetic induction flow meter (1) according to one of claims 1 to 6, characterised in that the coil (5) or the coils (5) is/are constructed as long coils, in particular the length (l) of each coil (5) corresponds to at least ten times the diameter (d) of the coil.

8. The magnetic-inductive flow meter (1) according to one of claims 1 to 7, characterized in that the coil (5) or the coils (5) is or are configured in the shape of an arc.

9. The magnetic induction flow meter (1) according to one of claims 6 to 8, characterised in that the coils are connected directly to the pole shoes (6, 7), in particular the coils (5) each have a coil core (14) and the coil cores (14) are connected to the pole shoes (6, 7).

10. The magnetic-inductive flow meter (1) according to one of claims 1 to 9, characterized in that the measuring tube (1) has a rectangular measuring section (8), wherein the pole shoes (6, 7) are arranged at the longitudinal sides of the measuring section (8), the measuring tube (2) has reinforcing ribs (17) and recesses (18) for the reinforcing ribs (17) are formed in the pole shoes (6, 7) corresponding to the reinforcing ribs (17).

11. The magnetic-inductive flow meter (1) according to one of claims 1 to 10, characterized in that the measuring tube (2) has a positioning element (19) and in that a positioning groove (20) for the positioning element (19) is formed in the pole shoe plate (6, 7).

12. The magnetic-inductive flow meter (1) according to one of claims 1 to 11, it is characterized in that the first pole shoe plate (6) and the second pole shoe plate (7) are respectively formed by first pole shoe sub-plates (21, 23) and second pole shoe sub-plates (22, 24), the first pole shoe sub-plates (21) of the first pole shoe plate (6) and the first pole shoe sub-plates (23) of the second pole shoe plate (7) are connected with each other, in particular by means of one or more coils (5) and/or one or more magnetic yoke elements (12) guiding the magnetic field, and the second pole shoe partial plate (22) of the first pole shoe plate (6) and the second pole shoe partial plate (24) of the second pole shoe plate (7) are connected with each other, in particular by means of one or more coils (5) and/or one or more magnetic yoke elements (12) which guide the magnetic field, so that the magnetic circuit arrangement (3) overall consists of two parts.

13. Magnetic circuit device (3) for a magnetic-inductive flow meter (1) for generating and guiding a magnetic field, having at least one first coil (5) for generating the magnetic field and a first pole shoe (6) and a second pole shoe (7), wherein the magnetic field is formed between the pole shoes (6, 7), and wherein a measuring tube (2) can be arranged between the pole shoes (6, 7),

characterized in that each pole shoe (6, 7) has a first side (9) facing the first coil (5) and a second side (10) opposite the first side (9), and in that at least two input regions (11) are formed for each pole shoe (6, 7) on the first side (9) of the pole shoe (6, 7) in each case for the purpose of inputting a magnetic field into the pole shoe (6, 7).

14. A magnetic circuit device (3) as claimed in claim 13, characterized in that the magnetic circuit device (3) is constructed in accordance with at least one of the features characterizing the magnetic circuit device (3) of claims 2 to 12.

Technical Field

The invention relates to a magnetic-inductive flow meter with a measuring tube for guiding an electrically conductive medium, with a magnetic circuit arrangement extending outside the measuring tube for generating and for guiding a magnetic field which penetrates the measuring tube at least partially perpendicularly to the flow direction of the medium, and with two electrodes for dividing a measuring voltage induced in the medium, wherein the magnetic circuit arrangement has at least one first coil and a first and a second pole shoe for generating the magnetic field, wherein the magnetic field is formed between the pole shoes, wherein the measuring tube is arranged between the two pole shoes, and wherein the electrodes are arranged on mutually opposite sides of the measuring tube, and an assumed connecting line between the two electrodes extends perpendicularly to the flow direction and perpendicularly to the magnetic field direction.

Background

Such magnetic-inductive flow meters are generally known from the prior art and are used to determine the flow rate of a medium. The measurement principle underlying flow measurement is based on the principle of charge separation of particles in a magnetic field. The charge separation results in an induced voltage, i.e. a measurement voltage, which is proportional to the flow velocity of the charge carriers moving in the medium, from which the flow in the measurement tube can thus be derived. The charge separation principle presupposes that the direction of flow of the medium in the measuring tube and the orientation of the magnetic field through the medium are not in the same direction. Although a vertical alignment of the measuring tube and the magnetic field is desirable, since then the effect of the charge separation is greatest, this is not absolutely necessary. When the magnetic circuit arrangement generates a magnetic field which penetrates the measuring tube at least partially perpendicularly to the flow direction, this then means a reasonable evaluation that the magnetic field penetrates the measuring tube "substantially perpendicularly", but at least one component of the magnetic field penetrates the measuring tube perpendicularly to the flow direction.

The magnetic circuit device has at least one coil generating a magnetic field. The magnetic field generated is mostly directed to the pole shoe by means of the magnetic field-guiding element. Pole shoes are used for leading the magnetic lines of the magnetic field to come out of the magnetic circuit in a defined way; the space between the pole pieces is traversed by a magnetic field. The pole shoes are preferably realized in a magnetic-inductive flowmeter by pole shoe plates, which have a small thickness and are therefore referred to below as pole shoe plates. The invention is not applicable to other forms of pole shoe.

The magnetic inductive flowmeter described is known from DE 102012014266 a 1. The magnetic circuit device of the magnetic inductive flowmeter described here comprises, in addition to two pole shoes, a total of four coils, which generate a magnetic field. Two coils are arranged on the opposite sides of the measuring tube and of the pole shoe plate. The two coils on each side are arranged in series with each other, wherein an electrode is arranged between the two coils. The coils are connected to one another and to one pole shoe plate each by a respective yoke element, so that a closed magnetic circuit arrangement is realized overall. The magnetic field generated in the coil or the field lines of the magnetic field are introduced into the pole shoe plates centrally via the yoke elements on the side of the pole shoe plates facing the coil.

Since the measurement accuracy of magnetic-inductive flowmeters depends on the one hand on the magnetic field strength and on the other hand on the homogeneity of the generated magnetic field, there is a constant effort to optimize the homogeneity of the magnetic field further in order to obtain better measurement results. The dimensions of the exterior of a magnetic induction flow meter are also important in practice; in this case, the measuring device itself is designed as compactly as possible, so that the measuring device can be used as space-saving as possible.

Disclosure of Invention

The object of the present invention is therefore to provide a magnetic-inductive flow meter which is distinguished by a better measurement sensitivity.

The previously stated and derived object is achieved in the magnetic-inductive flowmeter described at the outset in that each pole shoe plate has a first side facing the first coil and a second side opposite the first side, and at least two input regions of each pole shoe plate are formed on the first side of the pole shoe plate for the purpose of inputting a magnetic field into the pole shoe plate.

According to the invention, it was initially recognized that the homogeneity of the magnetic field formed between the pole-piece plates depends essentially on the input of the magnetic field into the pole-piece plates, i.e., in particular on the number of input regions through which the magnetic field or the field lines of the magnetic field generated by the coil are introduced into the pole-piece plates. The magnetic field generated by the coil is thus input into the pole shoe plate at the first side of the pole shoe plate by at least two input regions, in contrast to the prior art. In the prior art, each side has only one input area.

The input region refers to the region at which the magnetic field lines are introduced into the pole shoe plates. The input region is thus a region in the design of the structure where the pole shoe plate is in contact with or connected to other magnetic field-guiding or magnetic field-generating elements of the magnetic circuit arrangement. By configuring the at least two input regions at one side of the pole shoe plates and furthermore at the same side of the pole shoe plates, the homogeneity of the magnetic field between the pole shoe plates is improved. The better homogeneity of the magnetic field leads to a better measurement sensitivity of the magnetic-inductive flow meter.

This embodiment has proved particularly advantageous, in which the input region is configured close to the edge, i.e. in each case in the outer quarter of the longitudinal extent of the first side of the pole shoe plate. This not only achieves an advantageous magnetic field distribution between the pole shoe plates, but also achieves structural design advantages, which will be discussed in further detail below.

The input area can be implemented in different ways on the design structure. In a preferred embodiment of the magnetic-inductive flow meter, the coil is arranged on the side of the electrode. In one embodiment, a coil is used to generate the magnetic field. The coil is connected to the first side of the first pole shoe by a substantially Y-shaped yoke element and to the first side of the second pole shoe by a further substantially Y-shaped yoke element. The Y-arm of the yoke element is connected to the pole shoe plates, so that the two input regions are each formed at a first side of the pole shoe plates. When reference is made to a Y-shaped yoke element, all embodiments are meant here in which the yoke element consists of two parts. Such a yoke element also belongs, for example, to a Y-shaped yoke element in which the Y-stem turns linearly into a first Y-arm, from which a second Y-arm itself branches off at right angles and, furthermore, at right angles. The yoke element can, for example, also be designed in an h-shape. The two Y-shaped yoke elements are preferably of identical design.

A further particularly preferred embodiment of the magnetic induction flowmeter is characterized in that the magnetic circuit device has a second coil, so that the magnetic field across the measuring field is generated by both coils. In a preferred embodiment, the second winding is arranged on the side of the pole shoe opposite the first winding, the second side of the pole shoe thus facing the second winding. In order to input a magnetic field into the pole shoe plates, at least two further input regions of each pole shoe plate are formed on the second side of the pole shoe plates. This is preferably achieved in that the second coil is also connected to the first side of the first pole shoe via a first Y-shaped yoke element and to the first side of the second pole shoe via a second Y-shaped yoke element. The input region at the second side of the pole shoe plate is likewise preferably formed in the outer quarter of the longitudinal extent of the second side of the pole shoe plate. The magnetic circuit device thus has a total of two coils and at least four input regions per pole shoe plate, two input regions each being formed at a first side of the pole shoe plate and two input regions being formed at a second side of the pole shoe plate.

In a further preferred embodiment of the magnetic-inductive flowmeter according to the invention, the magnetic circuit arrangement likewise has two coils. In contrast to the previously described embodiments, however, the second coil arrangement is arranged on the same side of the pole shoe plate as the first coil. The two coils are preferably arranged one behind the other, as viewed in the flow direction, and the electrode is further preferably arranged between the coils. Each of the two coils inputs a magnetic field into the pole shoe plate via at least one input region, so that a total of at least two input regions is achieved.

In a further embodiment of the magnetic-inductive flowmeter according to the invention, the magnetic circuit arrangement has four coils, so that the magnetic field running through the measuring tube is generated by the four coils. Two coils are arranged on each side of the measuring tube, i.e. on each side of a respective electrode. The two coils are preferably arranged one behind the other on each side, viewed in the flow direction. It is particularly preferred if the electrodes are arranged further between the two coils, i.e. behind the first coil and in front of the second coil, as viewed in the flow direction.

In this embodiment, it is further provided that each coil is connected at least indirectly via an input region to the first pole shoe plate and via an input region to the second pole shoe plate. In total, four coils, therefore, at least two input regions are formed at the first side of the pole shoe plate and at least two input regions are likewise formed at the second side of the pole shoe plate.

By configuring the input region preferably in the outer region of the first and second side of the pole shoe plate and arranging the coil next to the electrode, i.e. before and after the electrode, viewed in the flow direction, the advantage is obtained that a large amount of installation space is provided for the coil, which can thus be configured to extend from the first pole shoe plate towards the second pole shoe plate.

In a preferred embodiment of the magnetic-inductive flow meter, the coil is therefore designed as a long coil. A long coil refers to a coil whose length is much greater than its diameter. Such a coil is particularly preferred, in which the length of the coil corresponds to at least ten times the diameter. The ratio of the length of a coil to its diameter, as far as one speaks of a long coil, depends inter alia on the nominal width of the respective coil. At nominal width DN 150, one refers to a long coil when the length of the coil corresponds to at least ten times the diameter. In the case of nominal width DN 600 and greater, one refers to a long coil when the length of the coil corresponds to at least twenty times the diameter. A long coil has the advantage over a short coil, the length of which and the coil radius are in the same order of magnitude that the magnetic field is homogeneous in the coil interior or significantly more homogeneous than in the interior of the short coil. Furthermore, significantly smaller undesired stray fields occur in long coils, as a result of which the susceptibility to stray fields can be reduced by using long coils. On the basis of the significantly smaller scattered field, the shielding measures for shielding the scattered field can be implemented in a simplified manner or can be dispensed with. The design according to the invention is therefore fundamentally different from the magnetic induction flowmeters of the prior art (in which the coil is arranged between the electrode and pole shoe plate and is therefore configured to fit into a limited space) described in the introduction of the description. Long coils also have the advantage that they can be produced in a material-saving manner.

In the previously described preferred embodiments of the magnetic-inductive flowmeter according to the invention, it is also possible for the coil to be connected to the pole shoe plate by a yoke element, in particular also by a Y-shaped yoke element. When using a Y-shaped yoke element, more than two input regions per side of the pole shoe plate can then be realized in a simple manner.

It is advantageous to design the magnetic circuit device of the magnetic-inductive flowmeter as simple as possible in terms of design, in particular to minimize the number of components used, in order to thereby also further increase the homogeneity of the magnetic field, since disruptive eddy currents can be generated by the connecting section or connecting point between the two components. In a further embodiment of the magnetic-inductive flowmeter, the coil is connected directly to the pole shoe plate. When it is stated that the coil is directly connected to the pole shoe plate, this means that no separate yoke element is used. The number of connection points in the magnetic circuit device can be reduced. Preferably, the coil has one coil core each and the coil cores are connected to the pole shoe plates. The coil core is understood here to mean a section which is surrounded by the turns of the coil, wherein the coil core can also extend beyond the turns of the coil without any significance. The length of the coil core extending beyond the turns is preferably less than one tenth of the length of the section of the coil core surrounded by the turns. The length can be selected in particular only until a connection to the pole shoe plate is possible.

In a particularly preferred embodiment, the coil core has grooves into which the pole shoe plates are inserted. The grooves are advantageously configured as slot-like grooves, wherein the width of the slot-like grooves preferably substantially corresponds to the thickness of the pole shoe plate, so that the pole shoe plate can be inserted into the slot-like grooves. The pole shoe is preferably correspondingly curved for this purpose on its first side.

In a further embodiment, the coil is formed in an arc shape, in particular in the shape of a circular arc. The bending radius of the coil is particularly preferably adapted to the outer radius of the measuring tube, so that the coil can be arranged on the measuring tube in a space-saving manner.

It is known from the prior art to design a measuring tube in such a way that it has a measuring section which is essentially rectangular in cross section and is perpendicular to the flow direction, wherein this measuring section of the measuring tube is the region of the measuring tube which is traversed by the magnetic field. When referring to a substantially rectangular cross section, the measuring tube is usually realized in such a way that the longitudinal sides of the rectangular cross section are arranged parallel to one another, wherein the short sides of the cross section do not have to be formed to be straight. Rather, the short sides are mostly designed in the form of arcs. In such a measuring tube, the electrodes are arranged on the short cross-sectional side of the measuring section. Furthermore, in flow meters with such measuring tubes, it is provided that the pole shoe plates are arranged on the longitudinal sides of the measuring section, i.e. on the long sides of the rectangular cross section. A design of the magnetic-inductive flow meter according to the invention is distinguished in that the magnetic-inductive flow meter has a measuring tube with a substantially rectangular measuring tube cross section, wherein pole shoe plates are arranged at the longitudinal sides of the measuring section. In order to mechanically reinforce the measuring section, reinforcing ribs are formed in the measuring section. The reinforcing rib is preferably formed on a longitudinal side of the measuring section. According to the invention, recesses corresponding to the reinforcing ribs for receiving the reinforcing ribs are formed in the pole shoe arranged on both longitudinal sides of the measuring section, in particular on the measuring section. This makes it possible to arrange the pole shoe plates as close as possible to the measuring tube, as a result of which the distance between the two pole shoe plates can be minimized. Depending on the design of the reinforcing ribs and the corresponding recesses in the pole shoe, the reinforcing ribs can perform a fixing function for the pole shoe.

In a further embodiment, the measuring tube has positioning elements and positioning recesses for the positioning elements are formed in the pole shoe plates. In contrast to the reinforcing ribs, the positioning elements do not reinforce the function of the measuring tube or measuring section, but serve to position the magnetic circuit device and in particular to fix the pole shoe.

By constructing the grooves in the pole shoe, stray fields and eddy currents in the pole shoe are also reduced. Thereby further improving the uniformity of the magnetic field. Furthermore, a faster switching of the magnetic field is achieved due to less stray fields and eddy currents.

In this way, a particularly preferred embodiment of the design of the magnetic-inductive flowmeter has proven to be one in which the first pole shoe plate and the second pole shoe plate are formed by a first pole shoe partial plate and a second pole shoe partial plate, respectively. The first pole shoe partial plates of the first pole shoe plate and the first pole shoe partial plates of the second pole shoe plate are connected to one another by means of magnetic field-guiding elements of the magnetic circuit device, in particular by means of one or more coils and/or one or more magnetic field-guiding yoke elements, and the second pole shoe partial plates of the first pole shoe plate and the second pole shoe partial plates of the second pole shoe plate are likewise connected to one another by means of magnetic field-guiding elements of the magnetic circuit device, in particular by means of one or more coils and/or one or more magnetic field-guiding yoke elements, so that the magnetic circuit device overall is composed of two parts. A particular advantage of this design is that the installation of the magnetic-inductive flowmeter is greatly simplified. The two parts of the magnetic circuit arrangement can be prefabricated and then only be inserted into the measuring tube of the magnetic-inductive flowmeter. If the pole shoe partial plates also have the positioning recesses described above, the positioning elements act through the positioning recesses after the insertion of the parts of the magnetic circuit device, so that the two parts of the magnetic circuit device are arranged fixedly at the measuring tube.

The two-part design of the pole shoe further inhibits the formation of stray fields and eddy currents.

In one embodiment of the magnetic circuit device with four coils, the respective pole shoe partial plates are connected to one another, for example, by two coils each. The second pole shoe partial plate of the first pole shoe plate and the second pole shoe partial plate of the second pole shoe plate are then likewise connected to one another by two coils.

The present invention relates not only to a magnetic-inductive flow meter, but also to a magnetic circuit device for a magnetic-inductive flow meter. The magnetic circuit device according to the invention is used for generating and guiding a magnetic field and has at least one first coil and a first pole shoe plate and a second pole shoe plate for generating the magnetic field, wherein the magnetic field is formed between the pole shoe plates. Between the pole shoe plates, a measuring tube of a magnetic-inductive flowmeter can be arranged, so that in the operating state, this measuring tube is penetrated by the magnetic field.

The magnetic circuit device according to the invention is distinguished in that each pole shoe plate has a first side facing the first coil and a second side opposite the first side, and in that at least two input points for each pole shoe plate are formed in each case on the first side of the pole shoe plate for the purpose of inputting a magnetic field into the pole shoe plate.

The magnetic circuit device according to the invention can be designed in particular in accordance with at least one of the features of the magnetic circuit device described above that characterize the magnetic circuit device of the magnetic-inductive flowmeter according to the invention. All the statements made in connection with the advantageous different embodiments of the magnetic circuit device of the magnetic-inductive flowmeter according to the invention apply to the magnetic circuit device according to the invention.

Drawings

There are now numerous possibilities for designing and expanding the magnetic-inductive flowmeter according to the invention and the magnetic circuit arrangement according to the invention in detail. For this purpose, reference is made to the claims dependent on the independent claims and to the description of preferred embodiments in conjunction with the drawings. In the drawings:

fig. 1 shows a first embodiment of a magnetic-inductive flowmeter with a first embodiment of a magnetic circuit arrangement;

fig. 2 shows a second embodiment of the magnetic circuit arrangement;

fig. 3 shows a third embodiment of the magnetic circuit arrangement;

fig. 4 shows a magnetic-inductive flowmeter with a fourth embodiment of the magnetic circuit arrangement;

fig. 5 shows the magnetic circuit device of fig. 4 in a first perspective view;

fig. 6 shows the magnetic circuit device of fig. 4 in a second perspective view;

fig. 7 shows the magnetic circuit device of fig. 4 in a third perspective view;

fig. 8 shows a fifth embodiment of the magnetic circuit device;

FIG. 9 is a measurement tube of a magnetic induction flow meter; and is

Fig. 10 shows a sixth embodiment of the magnetic circuit device.

Detailed Description

Fig. 1 shows a magnetic-inductive flow meter 1 with a measuring tube 2, the measuring tube 2 serving to guide an electrically conductive medium. The magnetic-inductive flow meter 1 has a magnetic circuit device 3 extending outside the measuring tube 2 for generating and guiding a magnetic field which penetrates the measuring tube 2 at least partially perpendicularly to the flow direction of the medium. The direction of flow of the medium is indicated by arrows. Furthermore, the magnetic-inductive flowmeter 1 has two electrodes 4 for dividing the measurement voltage induced in the medium. The electrode 4 is not visible in fig. 1. The magnetic circuit device 3 also has a coil 5 for generating a magnetic field and a first pole shoe 6 and a second pole shoe 7, wherein the measuring tube 2 is arranged with a measuring section 8 between the two pole shoe plates 6, 7 lying opposite one another. A magnetic field is formed between the pole shoe plates 6, 7, which magnetic field penetrates the measuring tube 2. Two electrodes 4 are likewise arranged on opposite sides of the measuring tube 2, wherein a not shown, imaginary connecting line between the two electrodes 4 extends perpendicular to the flow direction and perpendicular to the magnetic field direction.

The two pole shoes 6, 7 are designed such that they have a first side 9 and a second side 10, wherein the first side 9 of the pole shoe 6, 7 faces the coil 5 and the second side 10 is opposite the first side 9 and therefore on the side of the pole shoe 6, 7 facing away from the coil 5. In order to input the magnetic field generated in the coil 5 into the pole shoe plates 6, 7, two input regions 11 for each pole shoe plate 6, 7 are formed on the first side 9 of the two pole shoe plates 6, 7. The input regions 11 are in this case each located in the outer quarter of the longitudinal extent of the first side 9 of the pole shoes 6, 7. The input region 11 is thus formed in the edge region of the pole shoe plates 6, 7. By means of this embodiment of the magnetic circuit device 3, it is achieved that a uniform magnetic field is formed between the two pole shoes 6, 7. In order to input the magnetic field generated in the coil 5 into the pole shoe plates 6, 7, the coil 5 is connected via a respective Y-shaped yoke element 12 both to the first pole shoe plate 6 and to the second pole shoe plate 7.

Fig. 2 shows a further embodiment of the magnetic circuit device 3. In the illustrated embodiment, the magnetic circuit arrangement has two coils 5, so that the magnetic field penetrating the measuring tube 2 is generated by the two coils 5. The second coil 5 is arranged on the side of the pole shoe plates 6, 7 opposite the first coil 5, so that the second side 10 of the pole shoe plates 6, 7 faces the second coil 5. For the purpose of inputting the magnetic field generated by the second coil 5, two further input regions 11 are formed for each pole shoe 6, 7 on the second side 10 of the pole shoe 6, 7. A total of two coils 5 are therefore used to generate the magnetic field, wherein a total of four input regions 11 are formed per pole shoe 6, 7. The second coil 5 is likewise connected to the pole shoe plates 6, 7 in the input region 11 by a respective Y-shaped yoke element 12. The coil 5 is designed as a long coil.

In the embodiment of the magnetic circuit device 3 shown in fig. 1 and 2, the coil 5 or the coils 5 are arranged next to the electrode 4, i.e. at a height above the electrode 4, as viewed in the flow direction. Due to the close proximity of the coil 5 to the electrode 4, the electrode 4 may be influenced by the stray field of the coil 5 during operation of the magnetic induction flowmeter 1. This effect can be minimized by arranging a shielding metal housing around the coil 5. The metal housing is preferably designed in such a way that undesired stray fields are received and coupled into the pole shoe plates 6, 7. The metal housing is not shown in the figures.

Fig. 3 shows a further embodiment of a magnetic circuit device 3 with two coils 5. In contrast to the embodiment shown in fig. 2, the two coils 5 are not arranged centrally on the second side 9 of the pole shoe plates 6, 7, but rather at a height above the input point 11, as viewed in the flow direction. With this arrangement of the coil 5, the advantage is obtained that the influence on the electrode 4 due to the coil 5 is minimized, since the distance between the electrode 4 and the coil 5 is enlarged.

The electrodes 4 and the coils 5 are arranged one behind the other, as viewed in the flow direction, and are not arranged at the same height. The yoke element 12 is designed in the illustrated embodiment in the form of an h.

Fig. 4 shows a further embodiment of a magnetic-inductive flow meter 1, wherein the magnetic-inductive flow meter 1 has a measuring tube 2 and a magnetic circuit device 3. For dividing the measurement voltage, electrodes 4 are likewise provided. The magnetic circuit device 3 is particularly well visible in the perspective view shown. The magnetic circuit device 3 has a total of four coils 5, which are designed to generate a magnetic field. Two of the coils 5 are arranged on a first side 9 of the pole shoe plates 6, 7, and the other two coils 5 are arranged on a second side 10 of the pole shoe plates 6, 7. The two coils 5 on each side of the pole shoe plates 6, 7 are arranged one behind the other and parallel to one another, as viewed in the flow direction. One electrode 4 or a plurality of electrodes 4 are arranged on each side between two coils 5, i.e. behind the first coil 5 and in front of the second coil 5, as viewed in the flow direction, wherein preferably and as shown the coils 5 are arranged at the same distance from the electrodes. Each of the coils 5 is connected to the pole shoe plates 6, 7 by an input region 11. Each of the coils 5 is thus connected to the pole shoe plate 6 via an input region 11 and to the second pole shoe plate 7 via a further input region 11. Not shown, but covered by the present invention, is that each of the four coils 5 is connected to the pole piece plates 6, 7 by more than one input region 11. This can be achieved, for example, by using Y-shaped yoke elements, as shown in fig. 1 to 3.

As can be seen in the figure, the coil 5 is configured as a long coil. A long coil is distinguished in that the length l of the coil corresponds to a multiple of the diameter of the coil, i.e. in particular the length l of the coil corresponds to at least ten times the diameter. A homogeneous magnetic field inside the coil is thereby obtained. Furthermore, significantly smaller undesired scattered fields occur, which have a positive effect on susceptibility to interference and increase energy efficiency. Furthermore, shielding measures against the occurring stray fields are eliminated or can be significantly simplified due to the use of long coils.

As can be seen in particular in fig. 5 and 7, the coil 5 is also embodied in the form of a circular arc. The radius of the circular arc is adapted to the measuring tube geometry, i.e. to the outer diameter of the curved region of the measuring section 8 of the measuring tube 2, so that the coil 5 can be arranged close to the measuring tube 2, so that overall a magnetic circuit arrangement 3 can be formed which is very close to the measuring section 8 of the measuring tube 2. A compact magnetic-inductive flow meter 1 can thus be formed in a simple manner. The coil 5 has a coil core 14 which is substantially surrounded by the turns of the coil 5 and extends from the turns of the coil by an insignificant but partial amount. The protruding parts of the coil core 14 are shown well visible in fig. 7. In order to reduce the number of connection points in the magnetic circuit device 3 and thus reduce potential sources of eddy or magnetic stray fields, the pole shoe core 14 is connected directly to the pole shoe plates 6, 7 in the illustrated embodiment. For this purpose, the coil core 14 has recesses 15 at its ends, which are in the form of slots and into which the pole shoes 6, 7 are introduced. The pole shoes 6, 7 therefore have a connection section 16 connected to the coil core 14. In the exemplary embodiment shown, the connecting section 16 of the pole shoe plates 6, 7 is curved.

In order to reinforce the measuring section 8, reinforcing ribs 17 are formed in the measuring tube 2 in the region of the measuring section 8. The pole shoe plates 6, 7 of the magnetic circuit device 3 have corresponding recesses 18 for receiving the reinforcing ribs 17. These recesses 18 for the reinforcing ribs can be seen particularly well in fig. 5 and 6, in which the magnetic circuit device 3 shown in fig. 4 is shown in a further perspective view. By forming the grooves 18 for the reinforcing ribs 17, it can be ensured that the pole shoe plates 6, 7 are arranged close to the measuring section 8 and therefore close to one another, thus improving the homogeneity of the magnetic field formed between the pole shoe plates 6, 7. Furthermore, the formation of stray fields and eddy currents is reduced by the grooves 18, whereby the homogeneity of the magnetic field formed between the pole shoe plates 6, 7 is further improved.

For fixing and positioning the magnetic circuit device 3 at the measuring tube 2, a positioning element 19 is provided, as can be seen in particular in fig. 4. A total of four positioning elements 19 are provided on each side, i.e. on each pole shoe 6, 7. The pole shoes 6, 7 have corresponding positioning recesses 20, through which the positioning elements 19 are guided. The formation of stray fields and eddy currents is also reduced by the configuration of the detent 29.

Particularly advantageous is a design in which the pole shoe plates 6, 7 are formed in two parts, namely a first pole shoe plate 6 having a first pole shoe partial plate 21 and a second pole shoe partial plate 22 and a second pole shoe plate 7 having a first pole shoe partial plate 23 and a second pole shoe partial plate 24. The first pole shoe part 21 of the first pole shoe 6 is connected to the first pole shoe part 23 of the second pole shoe 7 via the coil 5. The second pole shoe partial plate 22 of the first pole shoe plate 6 is connected to the second pole shoe partial plate 24 of the second pole shoe plate 7 via the other two coils 5. The entire magnetic circuit device 3 is thus generally composed of two parts, namely by the first part 25 and the second part 26 which are not connected to one another. This embodiment has the advantage that the assembly of the magnetic circuit arrangement is greatly simplified. The two parts 25, 26 can be inserted, for example, onto the measuring section 8 of the measuring tube 2. After the insertion of the two parts 25, 26, the positioning element 18 can then be connected to the measuring tube 2 via the positioning opening 20. The positioning element 19 can alternatively be connected to the measuring tube 2 or be formed integrally with this measuring tube and the parts 25, 26 can be latched to the positioning element 19 when inserted onto the measuring section 8 of the measuring tube 2. The two parts 25, 26 of the magnetic circuit arrangement 3 are thus fixed to the measuring tube 2 and can no longer perform a significant relative movement with respect to the measuring tube 2. The two-part magnetic circuit device 3 can be seen particularly clearly in fig. 5 and 6. Fig. 5 shows a perspective view of the magnetic circuit device 3, and fig. 6 shows a plan view of the magnetic circuit device 3.

The magnetic-inductive flow meter 1 can have a measuring tube 2 with geometrically different measuring sections. The measuring section 8 of the measuring tube 2 shown in fig. 1 and 4 is rectangular in shape and therefore has a rectangular flow cross section. The measuring section has in particular two flat sides, at which pole shoes are arranged. In a further embodiment, the measuring section 8 of the measuring tube 2 has a circular flow cross section. Fig. 7 shows a magnetic circuit arrangement 3 which is advantageously designed for using a measuring tube 2 with a measuring section 8 having a rectangular flow cross section, whereas fig. 8 shows a magnetic circuit arrangement 3 which is advantageously designed for using a measuring tube 2 with a measuring section 8 having a circular flow cross section.

The pole shoe partial plates 21, 22, 23, 24 are divided in two embodiments into a first section 28 and a second section 29, respectively. The first section 28 and the second section 29 are at an internal angle to each otherAnd (4) arranging. Inner angleThe angle between the first section 28 and the second section 29 on the side of the pole shoe partial plates 21, 22, 23, 24 facing the measuring tube 2 arranged between the pole shoe plates 6, 7 is referred to. Inner angleThis is preferably achieved in that the first section 28 is bent away from the second section 29. In the magnetic circuit device 3 shown in fig. 7, the inner angleGreater than 180. A nearly rectangular shape of the magnetic circuit device 3 is thereby obtained. In the magnetic circuit device 3 shown in fig. 8, the inner angleLess than 180. A nearly circular shape of the magnetic circuit device 3 is thereby obtained.

The magnetic circuit device 3 shown in fig. 2 and 3 also has an interior angle of more than 180 ° between the first section 28 and the second section 29. Because the pole shoes 6, 7 are of one-piece construction, the pole shoes 6, 7 have a first section 28 and two second sections 29, which adjoin the first section 28 on both sides. The magnetic circuit arrangement 3 shown is correspondingly designed for a measuring tube 2 with a measuring section 8 having a rectangular flow cross section.

Fig. 9 shows the measuring tube 2 of the magnetic-inductive flowmeter 1. In this case, a rectangular measuring section 8 can be seen particularly well, which has a reinforcing rib 17, wherein the reinforcing rib 17 is arranged crosswise on the measuring section 8. Furthermore, a fastening section 27 for fastening the positioning element 19 can be seen. These positioning elements 19 can preferably be screwed, for example, into the measuring tube 2, wherein the fastening section 27 then has a counter thread corresponding to the thread formed at the positioning elements 19.

Fig. 10 shows another diagram of the magnetic circuit device 3. The magnetic circuit device 3 has two pole shoes 6, 7 and furthermore two coils 5. Both coils 5 are arranged at the first side 9 of the pole shoe plates 6, 7. In the example shown, the pole shoe plates 6, 7 are designed such that they do not have an additional positioning recess 20. Although not shown, part of the invention is all the embodiments of the pole shoe plates 6, 7 as described above in connection with the two coils arranged at the first side 9 of the pole shoe plates 6, 7.

List of reference numerals

1 magnetic induction type flow meter

2 measuring tube

3 magnetic circuit device

4 electrodes

5 coil

6 first pole shoe plate

7 second pole boot board

8 measurement section

First side of 9-pole boot plate

Second side of 10-pole shoe

11 input area

12-yoke element

14 coil core

15 groove

Connecting section of a 16-pole shoe plate

17 reinforcing rib

18 grooves for stiffening ribs

19 positioning element

20 positioning groove

21 first pole shoe plate of the first pole shoe plate

22 second pole shoe sub-plate of the first pole shoe plate

23 first pole shoe plate of second pole shoe plate

24 second pole shoe plate of second pole shoe plate

25 first part of magnetic circuit device

26 second part of the magnetic circuit device

27 fastening section for a positioning element

28 first section

29 second section