JP2006010315A - Electromagnetic flowmeter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize an electromagnetic flowmeter which makes the electromagnetic loss small while being a simple structure. <P>SOLUTION: In the pipe of the flowmeter an insulation resin layer is formed, in which porous plates are laid. The part wherein magnetic field of porous plates is passed through is provided with magnetic members. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electromagnetic flowmeter in which an insulating resin layer is formed on the inner surface of a pipe of a measuring tube, and a porous plate is embedded in the insulating resin layer in order to prevent the insulating resin layer from peeling from the pipe.

In an electromagnetic flowmeter that uses the electromagnetic induction phenomenon to measure the flow rate of fluid flowing in a measurement tube, if a part of the measurement tube is a conductive material such as metal, an electromotive force generated in the fluid flows to the ground. Since the short circuit causes an error, the tube wall which is the liquid contact surface of the measurement tube is covered with an insulating resin layer.
Since this insulating resin layer has poor adhesion to metal and is easily peeled off from the measuring tube, a porous plate is usually embedded in the insulating resin layer to prevent the insulating resin layer from peeling off.

4 is a schematic cross-sectional view showing a configuration example of a conventional electromagnetic flow meter, and FIG. 5 is an axial cross-sectional view of a measurement tube in the conventional example of FIG.
4 and 5, an insulating resin layer 11 is formed on the inner surface of the pipe 10 of the measuring tube 1, and a porous plate 12 is embedded in the insulating resin layer 11.
The pipe 10 and the porous plate 12 are made of, for example, nonmagnetic stainless steel, and the insulating resin layer 11 is made of, for example, a fluororesin or a polyurethane resin.

The porous plate 12 has a large number of holes and is formed in a circular tube shape. The porous plate 12 is inserted into the pipe 10 and the circumferences of both ends of the porous plate 12 are fixed to the pipe 10 by welding or the like.
The insulating resin layer 11 is reinforced when the insulating resin enters a large number of holes in the porous plate 12 and is integrated with the porous plate 12, and can prevent peeling.

  A magnetic field perpendicular to the flow direction is applied to the fluid flowing through the measuring tube 1 by applying current to the coils 13 arranged on the upper and lower sides of the pipe 10 and perpendicular to the fluid flow direction and the magnetic field direction. The electromotive force generated in the fluid is detected by the electrode 14 arranged in the direction. Since the electromotive force generated when the fluid flows in the magnetic field is proportional to the average fluid flow velocity, the fluid flow rate can be measured.

For example, Patent Document 1 discloses an electromagnetic flow meter in which a pipe thickness of a measurement tube is reduced by fixing a porous plate embedded in an insulating resin layer to a protrusion on an inner surface of the measurement tube.
JP-A-5-18800

However, the conventional examples of FIGS. 4 and 5 have the following problems.
Since the inner diameter dimension and thickness of the insulating resin layer and the thickness of the pipe are determined by their strength, performance, the diameter of the pipe to be connected, etc., the inner diameter dimension of the insulating resin layer is simply reduced or the insulating resin layer and the pipe The thickness cannot be reduced.
In addition, in an electromagnetic flow meter that requires a porous plate to prevent the insulating resin layer from peeling off, the outer dimensions of the measurement tube are increased by the amount of the porous plate.

  Here, the largest loss on the magnetic circuit of the electromagnetic flowmeter is the loss of the gap sandwiched between the upper and lower coils. Therefore, if the outer dimension of the measuring tube increases and the distance between the upper and lower coils increases, the magnetoresistance However, there is a problem that the magnetic loss increases with the increase of.

  On the other hand, there are some which increase the strength by adding a groove to the pipe of the measuring tube, and reduce the magnetic loss by reducing the outer dimension of the measuring tube by reducing the thickness of the pipe. There was a problem that special processing was required.

  The present invention has been made to solve the above-described problems. By providing a magnetic member at a location where a magnetic field of a porous plate passes, an electromagnetic flow meter that reduces magnetic loss while having a simple structure is provided. It aims to be realized.

In order to achieve such a subject, the present invention is configured as follows.
(1) In an electromagnetic flow meter in which an insulating resin layer is formed on the pipe inner surface of a measurement tube and a porous plate is embedded in the insulating resin layer,
An electromagnetic flow meter, wherein a magnetic member is provided at a location where the magnetic field of the porous plate passes.

(2) The magnetic flowmeter according to (1), wherein the magnetic member is a porous plate having magnetism.

(3) The electromagnetic flowmeter according to (2), wherein the magnetic porous plate constitutes a part of the porous plate.

(4) The electromagnetic flowmeter according to (2), wherein the magnetic porous plate is attached to the porous plate.

The present invention has the following effects.
In the present invention, the magnetic member is provided at a location where the magnetic field of the porous plate embedded in the insulating resin layer passes. Since the magnetic member has a high magnetic permeability, the magnetic resistance is reduced.
As a result, even when the outer dimensions of the measuring tube are large, the magnetic loss can be reduced and the generated electromotive force can be increased without impairing the strength of the measuring tube.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic sectional view showing an embodiment of the present invention, and FIG. 2 is an axial sectional view of a measuring tube in the embodiment of FIG. The same parts as those in the previous figure are given the same reference numerals.
1 and 2, an insulating resin layer 11 is formed on the inner surface of the pipe 10 of the measuring tube 1, and in the insulating resin layer 11, a porous plate 20 and a magnetic porous plate (this is a magnetic porous plate). 21) is buried.

  A magnetic porous plate 21 is provided at a location where the magnetic field of the porous plate 20 passes. The porous plate 20 has a space in which the magnetic porous plate 21 is fitted. The magnetic porous plate 21 is fitted in this space and welded to the porous plate 20 to thereby form the magnetic porous plate 21. Constitutes part of the porous plate 20.

The porous plate 20 and the magnetic porous plate 21 have a large number of holes and are formed in a circular tube shape. The porous plate 20 and the magnetic material porous plate 21 are inserted into the pipe 10, and the circumferences of both ends of the porous plate 20 are welded to the pipe 10. It is fixed.
The insulating resin layer 11 is reinforced by the insulating resin entering a large number of holes in the porous plate 20 and the magnetic porous plate 21 and integrated with the porous plate 20 and the magnetic porous plate 21 to prevent peeling. can do.

  Moreover, since the magnetic permeability of the magnetic porous plate 21 provided at the location where the magnetic field passes is high, the magnetic resistance is reduced and the magnetic loss can be reduced.

FIG. 3 is a schematic sectional view showing another embodiment of the present invention.
In FIG. 3, a magnetic porous plate 31 is provided at a location where the magnetic field of the porous plate 30 passes. The magnetic porous plate 31 is attached to the inner surface of the porous plate 30 by welding or the like.
In this case, special processing is not necessary for the porous plate 30 as compared with FIGS.
In this figure, the magnetic porous plate 31 is attached to the inner surface of the porous plate 30, but may be attached to the outer surface.

The porous plate 30 and the magnetic porous plate 31 have a large number of holes, are formed in a circular tube shape, are inserted into the pipe 10, and the circumferences of both ends of the porous plate 30 are welded to the pipe 10. It is fixed.
The insulating resin layer 11 is reinforced by the insulating resin entering a large number of holes in the porous plate 30 and the magnetic porous plate 31 and integrated with the porous plate 30 and the magnetic porous plate 31 to prevent peeling. can do.

  In addition, since the porous plate 31 having a magnetic field is attached to the porous plate 30, the insulating resin layer 11 becomes thicker by the porous plate 31 having the magnetic field than in FIGS. However, since the magnetic permeability of the magnetic porous plate 31 provided at the location where the magnetic field passes is higher than when there is no porous plate 31 having a magnetic field, the magnetic resistance is reduced and the magnetic loss is reduced. Can be reduced.

  The porous plates 20 and 30 are made of, for example, non-magnetic stainless steel, and the magnetic porous plates 21 and 31 are made of, for example, silicon steel, magnetic stainless steel, iron, permalloy, or the like.

It is typical sectional drawing which shows one Example of this invention. It is an axial sectional view of the measuring tube in the embodiment of FIG. It is typical sectional drawing which shows the other Example of this invention. It is typical sectional drawing which shows the structural example of the conventional electromagnetic flowmeter. It is an axial sectional view of the measuring tube in the conventional example of FIG.

Explanation of symbols

1 Measurement Tube 10 Pipe 11 Insulating Resin Layer 20, 30 Porous Plate 21, 31 Magnetic Porous Plate

Claims (4)

In an electromagnetic flow meter in which an insulating resin layer is formed on the pipe inner surface of the measurement tube and a porous plate is embedded in the insulating resin layer,
An electromagnetic flow meter, wherein a magnetic member is provided at a location where the magnetic field of the porous plate passes.   The electromagnetic flowmeter according to claim 1, wherein the magnetic member is a porous plate having magnetism.   The electromagnetic flowmeter according to claim 2, wherein the magnetic porous plate constitutes a part of the porous plate. The electromagnetic flowmeter according to claim 2, wherein the porous plate having magnetism is attached to the porous plate.

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