JP2004325369A - Electromagnetic flow meter - Google Patents

Abstract

Provided is an inexpensive electromagnetic flowmeter capable of reducing variations in magnetic field distribution, improving high-frequency characteristics, and reducing costs.
An electromagnetic flowmeter having a saddle-shaped coil and a return magnetic path,
A plate core having a semicircular cross-section provided with one surface in contact with the peripheral surface of the measurement tube, a saddle-shaped coil provided on the other surface of the plate core, and a saddle-shaped coil covering the outer surface of the saddle-shaped coil A return magnetic path bent at the inner diameter portion of the coil in the direction of the measurement tube and in contact with the plate core, and provided at a position where the plate core and the return magnetic path are in contact with each other, the plate core and the return magnetic path are connected to each other; An electromagnetic flowmeter comprising a connection means.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inexpensive electromagnetic flowmeter capable of reducing variations in magnetic field distribution and improving high-frequency characteristics.
[0002]
[Prior art]
FIG. 4 is an explanatory diagram of a configuration of a conventional example generally used in the related art, which is disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-071408 (for example, see Patent Document 1).
[0003]
In the figure, reference numeral 1 denotes a measuring tube, in which case ceramics is used.
Reference numeral 2 denotes a lining body provided in the measuring tube 1.
Reference numeral 3 denotes a detection electrode provided in the measurement tube 2.
[0004]
Reference numeral 4 denotes a saddle-shaped exciting coil, and reference numeral 5 denotes a saddle-shaped pole piece core.
6 is a feedback circuit. The feedback magnetic path 6 is generally made of an iron-based material such as a silicon steel plate.
[0005]
[Patent Document 1]
JP-A-2002-071408 (page 2, FIG. 8)
[0006]
[Problems to be solved by the invention]
However, such an apparatus has the following problems.
Although the magnetic field distribution is formed by the dimensions of the saddle-shaped pole piece core 5 and the saddle-shaped coil 4, the dimensional variation of the coils 4 and 5 and the like is large, and individual differences are increased.
Further, a pole piece core 5 is provided. An eddy current is generated in this portion, and the frequency characteristics of the magnetic circuit are poor, so that it is difficult to excite at a high frequency.
[0007]
An object of the present invention is to solve the above-mentioned problems, and to provide an inexpensive electromagnetic flowmeter which can reduce the variation in the magnetic field distribution, improve the high frequency characteristics, and can reduce the variation.
[0008]
[Means for Solving the Problems]
In order to achieve such an object, according to the present invention, in the electromagnetic flow meter of claim 1,
In an electromagnetic flowmeter having a saddle-shaped coil and a return magnetic path,
A plate core having a semicircular cross-section provided with one surface in contact with the peripheral surface of the measurement tube, a saddle-shaped coil provided on the other surface of the plate core, and a saddle-shaped coil covering the outer surface of the saddle-shaped coil A return magnetic path bent at the inner diameter portion of the coil in the direction of the measurement tube and in contact with the plate core, and provided at a position where the plate core and the return magnetic path are in contact with each other, the plate core and the return magnetic path are connected to each other; Connection means.
[0009]
In claim 2 of the present invention,
The connection means is a stud bolt for connecting the plate core and the return magnetic path.
[0010]
In claim 3 of the present invention,
The connection means has a caulking structure for connecting the plate core and the return magnetic path.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is an explanatory diagram of a main part of an embodiment of the present invention, and FIG. 2 is a plan view of the main part of FIG.
In the figure, the configuration of the same symbol as in FIG. 4 represents the same function.
Hereinafter, only differences from FIG. 4 will be described.
[0012]
The plate core 11 having a semicircular cross section is provided so that one surface thereof is in contact with the peripheral surface of the measuring tube 1 and has a semicircular cross section.
The saddle coil 4 is provided on the other surface of the plate core 11.
The return magnetic path 12 covers the outer surface of the saddle-shaped coil 4, and is bent in a radial direction of the measurement tube 1 and in a direction approaching the measurement tube 1 at an inner diameter portion of the saddle-shaped coil 4, and comes into contact with the plate core 11. .
[0013]
The connection means 13 is provided at a position where the plate core 11 and the return magnetic path 12 are in contact with each other, and connects the plate core 11 and the return magnetic path 12.
In this case, stud bolts are used.
[0014]
In the above configuration, the return magnetic path 12 covers the outer surface of the saddle-shaped coil 4 and is bent at the inner diameter portion of the saddle-shaped coil 4 in the radial direction of the measuring tube 1 and in a direction approaching the measuring tube 1. Therefore, even if the pole piece core 5 is eliminated, the magnetic field can be increased.
[0015]
Further, by inserting the plate core 11 below the feedback magnetic path 12 and the saddle-shaped coil 4, it is possible to further increase the magnetic field.
[0016]
Since the plate core 11 can be manufactured by processing such as pressing, the dimensional accuracy is stable, the variation in individual differences is small, the individual variation in the magnetic circuit can be reduced, and the variation in products can be reduced.
[0017]
Further, the plate core 11, the saddle-shaped coil 4, and the return magnetic path 12 can be easily positioned by the connecting means 13 (stud bolts), so that the assemblability becomes easy.
[0018]
Further, the pole piece core 5 that generates an eddy current can be eliminated, the frequency characteristics of the magnetic circuit can be improved, and excitation can be performed at a high frequency.
[0019]
As a result,
By providing the return magnetic path 12 and the plate core 11 bent toward the measurement tube 1 at the inner diameter portion of the saddle-shaped coil 4, it is possible to form an equivalent magnetic field without the pole piece core 5. The total is obtained.
[0020]
Further, by employing the plate core 11, it is possible to reduce variations in the magnetic field distribution due to individual differences, and to obtain an electromagnetic flowmeter capable of reducing individual differences in products.
[0021]
By eliminating the pole piece core 5 that generates the eddy current, the frequency characteristics of the magnetic circuit can be improved, and an electromagnetic flowmeter that can be excited at a high frequency can be obtained.
[0022]
By eliminating the pole piece core 5, it is possible to obtain an electromagnetic flowmeter that can reduce costs.
[0023]
The connecting means 13 (stud bolt) makes it possible to easily fix the return magnetic path 12, the saddle-shaped coil 4, and the plate core 11, and to obtain an electromagnetic flowmeter capable of reducing man-hours.
[0024]
FIG. 3 is an explanatory diagram of a main part configuration of another embodiment of the present invention.
In the present embodiment, the saddle-shaped coil 4 is sandwiched between the plate core 11 and the return magnetic path 12, and a caulking structure 21 is employed as the connection means 13.
[0025]
As a result, a magnetic circuit has a unit structure, and an electromagnetic flow meter that can be easily positioned and assembled can be obtained.
[0026]
It should be noted that the foregoing description has shown only specific preferred embodiments for the purpose of explanation and illustration of the present invention. Therefore, the present invention is not limited to the above-described embodiment, but includes many more changes and modifications without departing from the spirit thereof.
[0027]
【The invention's effect】
As described above, according to the first aspect of the present invention, the following effects can be obtained.
By providing the return magnetic path and the plate core bent toward the measuring tube side at the inner diameter portion of the saddle-shaped coil, it is possible to obtain an electromagnetic flowmeter capable of forming an equivalent magnetic field without the pole piece core.
[0028]
Further, by employing the plate core, it is possible to reduce the variation of the magnetic field distribution due to individual differences, and to obtain an electromagnetic flowmeter capable of reducing the individual differences of products.
[0029]
By eliminating the pole piece core that generates the eddy current, the frequency characteristics of the magnetic circuit can be improved, and an electromagnetic flowmeter that can be excited at a high frequency can be obtained.
[0030]
By eliminating the pole piece core, it is possible to obtain an electromagnetic flowmeter capable of reducing costs.
[0031]
By using the connecting means, it is possible to easily fix the return magnetic path, the saddle-shaped coil, and the plate core, and to obtain an electromagnetic flowmeter capable of reducing man-hours.
[0032]
According to the second aspect of the present invention, the following effects are obtained.
Since the connecting means uses stud bolts for connecting the plate core and the return magnetic path, the stud bolts have marketability and can be easily obtained, so that an inexpensive electromagnetic flowmeter can be obtained.
[0033]
According to the third aspect of the present invention, the following effects are obtained.
Since the connecting means uses a caulking structure for connecting the plate core and the return magnetic path, the magnetic circuit has a unit structure, and an electromagnetic flowmeter that can be easily positioned and assembled can be obtained.
[0034]
Therefore, according to the present invention, variation in the magnetic field distribution can be reduced, high-frequency characteristics can be improved, and an inexpensive electromagnetic flowmeter can be realized.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a main configuration of an embodiment of the present invention.
FIG. 2 is a plan view of a main part of FIG.
FIG. 3 is an explanatory view of a main part configuration of another embodiment of the present invention.
FIG. 4 is an explanatory view of a configuration of a main part of a conventional example generally used in the related art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Measuring tube 2 Lining body 3 Detecting electrode 4 Saddle-shaped excitation coil 5 Saddle-shaped pole piece core 6 Feedback circuit 11 Plate core 12 Return magnetic path 121 Depression 13 Connection means 21 Caulking structure

Claims (3)

In an electromagnetic flowmeter having a saddle-shaped coil and a return magnetic path,
A plate core having a semicircular cross-section provided with one surface in contact with the peripheral surface of the measurement tube,
A saddle-shaped coil provided on the other side of the plate core,
A return magnetic path that covers the outer surface of the saddle coil and is bent toward the measurement tube at the inner diameter portion of the saddle coil and contacts the plate core;
An electromagnetic flowmeter, comprising: a connecting means provided at a position where the plate core and the return magnetic path are in contact with each other and connected to the plate core and the return magnetic path. The electromagnetic flowmeter according to claim 1, wherein the connection means is a stud bolt connecting the plate core and the return magnetic path. The electromagnetic flowmeter according to claim 1, wherein the connection means has a caulking structure for connecting the plate core and the return magnetic path.

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