JPH0734325U - Electromagnetic flow meter - Google Patents

Abstract

(57) [Summary] [Purpose] By using an outer core, an adhesive,
The signal lead wire can be wired in parallel with the magnetic field of the exciting coil without using any tape or the like, and 90 ° noise is reduced. [Structure] The outer core 20 has a plurality of through holes 21 (21
a to 21d) are formed separately on the lines that coincide with the positions of the electrodes 4A and 4B and are orthogonal to the fluid flow direction, and the signal lead wires 10A and 10B are inserted and fixed in these through holes, respectively.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electromagnetic flow meter for measuring the flow rate of a conductive fluid flowing in a measuring pipe.

[0002]

[Prior art]

 An electromagnetic flow meter (such as Japanese Utility Model Publication No. 2-28411) that measures the flow rate of a conductive fluid flowing in a measuring tube using the principle of electromagnetic induction uses an electromotive force, which is a signal generated in the fluid, as its flow direction. The electrodes are arranged in the direction orthogonal to the direction to extract. FIG. 4 and FIG. 5 are external perspective views and cross-sectional views showing a conventional example of such an electromagnetic flow meter. A pair of saddle type exciting coils 4A and 4B which are provided to form a magnetic field at right angles to the flow direction of the fluid to be measured 2 are attached so as to penetrate through the central portion of the measuring tube 1 so as to be orthogonal to the magnetic field. A pair of electrodes 6A and 6B facing the inside of the pipe 5 are also inner and outer cores provided on the outer periphery of the measuring pipe 1, 7 is a converter, and 8 is a measuring pipe 1 for providing electrical insulation and corrosion resistance. Lining of fluororesin, neoprene, etc. lined on the inner wall of 10A, 10B is a signal lead wire connecting the electrodes 4A, 4B and the converter 7, 11 is a case, 12 is a signal lead wire 10A, 10B. Seal to seal In braided wire, and an electromagnetic flowmeter 13 by these.

[0003]

[Problems to be solved by the device]

 By the way, when the signal lead wires 10A and 10B are arranged so as to be inclined with respect to the magnetic field formed by the exciting coils 3A and 3B when viewed from the side of the measuring tube 1 (direction orthogonal to the axis), the generated magnetic field is generated. When crossing the inside of the loop surface of the signal lead wires 10A and 10B (the surface surrounded by the line A connecting both electrodes 4A and 4B and the signal lead wires 10A and 10B) S, noise called 90 ° noise is generated. There is a problem that the measurement accuracy is deteriorated by superimposing it on 10A and 10B. Therefore, the signal lead wires 10A, 10B are raised vertically from the electrodes 4A, 4B so as to be perpendicular to the flow direction of the fluid, in other words, perpendicular to the axis of the measuring tube 1, and the magnetic flux and the loop surface of the signal lead wires 10A, 10B are crossed. It is desirable to reduce the intersection angle with S.

Therefore, conventionally, as a method of solving such a problem, for example, a groove extending in the circumferential direction is provided on the upper outer peripheral surface of the measuring tube 1, and a signal lead wire is wired in the groove to form an adhesive, There has been proposed an electromagnetic flowmeter (Japanese Utility Model Publication No. 3-51707) in which a signal lead wire is fixed by a tape or the like or a signal lead wire is formed of an elastic band-shaped metal plate. However, in the former case, it is necessary to process and form a groove in the measuring tube, so the number of manufacturing steps increases, and fixing the signal lead wire with an adhesive or tape makes the work troublesome. There was a problem. On the other hand, in the latter case, while the installation work is easy, there is a problem that compatibility is lacking and parts management is troublesome because it is necessary to manufacture a band-shaped metal plate of a size suitable for each model. It was

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and the purpose thereof is to use an outer core without requiring a single adhesive, tape, or the like. An object of the present invention is to provide an electromagnetic flow meter in which a signal lead wire can be wired in parallel with a magnetic field of an exciting coil and 90 ° noise can be reduced.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a pair of exciting coils which are provided on the outer circumference of a measuring pipe and which form a magnetic field perpendicular to the flow direction of the fluid to be measured, and to both the magnetic field and the fluid flow direction. In an electromagnetic flowmeter having a pair of electrodes arranged so as to be orthogonal to each other so as to face the measurement tube and an outer core arranged outside the pair of exciting coils, the electrode position on the outer peripheral surface of the outer core is the same as that of the electrode position. In addition, a plurality of through holes are formed separately on a line orthogonal to the fluid flow direction, and a signal lead wire whose one end is connected to the electrode is inserted into the through hole and fixed.

[0007]

In the present invention, the signal lead wire is inserted and fixed in the through hole of the outer core. Since the through hole is formed on a line on the outer circumferential surface of the outer core, which coincides with the electrode position and is orthogonal to the fluid flow direction, the through hole prevents the loop surface of the signal lead wire from being inclined with respect to the magnetic field.

[0008]

【Example】

 Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. 1 is a side view showing an embodiment of an electromagnetic flow meter according to the present invention, FIG. 2 is a sectional view of the electromagnetic flow meter, and FIG. 3 is a perspective view of an outer core. In the figure, the same components as those in FIGS. 4 and 5 are designated by the same reference numerals, and the description thereof will be omitted. In these drawings, in this embodiment, an outer core 20 disposed on the outer circumference of the measuring tube 1 and covering the exciting coils 3A and 3B is composed of a substantially semi-cylindrical upper core 20A and a lower core, which are vertically divided into two parts. 20B, a plurality of, for example, four through holes 21 (21a to 21d) are arranged side by side in the central portion of the peripheral surface of the upper core 20A in the circumferential direction, and the signal lead wires 10A are provided in these through holes 21. , 10B are inserted and fixed. The through hole 21 is formed so as to be located on one line orthogonal to the axis of the outer core 20. Although the through hole 21 is formed to be long in the circumferential direction in this embodiment, it is not limited to this and may be a round hole. In addition, the hole width d of the through hole 21 is preferably set to be small in order to restrict the movement of the signal lead wires 10A and 10B in the axial direction of the measuring tube 1. The number of through holes 21 may be two or more for each lead wire, and may be appropriately increased or decreased depending on the size of the measuring tube 1.

The upper core 20A and the lower core 20B are formed in a semi-cylindrical shape with an opening angle larger than 180 °, so that when they are arranged on the outer circumference of the measuring tube 1, as shown in FIG. Are overlapped and joined together. In addition, U-shaped grooves 23 and 24 are formed in the central portions of both side edges of the upper core 20A and the lower core 20B, respectively. These U-shaped grooves 23, 24 are formed so as to be positioned on the line connecting the centers of the through holes 21, and the outer core 20 is formed by combining the upper core 20A and the lower core 20B. When it is arranged on the outer periphery of 1, the electrode lead-out / lead wire lead-out holes 25, 26 are formed.

One signal lead wire 10A, one end of which is connected to the outer end of the electrode 4A, is led out of the outer core 20 through the electrode lead-out / lead wire lead-out hole 25 and then through the through hole 21a. It is reinserted into the inside 20 and is led out to the outside again from the through hole 21b and is led above the upper core 20A. On the other hand, the other signal lead wire 10B, one end of which is connected to the outer end of the electrode 4B, is led out of the outer core 20 through the electrode lead-out / lead wire lead-out hole 26, and then again through the through hole 21c. It is inserted into the inside, is led out to the outside again from the through hole 21d, merges with the one lead wire 10A, and is led to the converter 7 (FIG. 4). In this case, when the lead wires 10A, 10B led out from the through holes 21b, 21c are pulled with a pin so as not to loosen, the lead wires 10A, 10D are caused by the through holes 21a to 21d and the core thick portion between these through holes. Since it is possible to prevent the movement of the B outer core 20 in the axial direction, it is possible to reliably prevent the inclination of the loop surface (S) of the lead wires 10A and 10B. The other structure is the same as the conventional structure shown in FIGS. 4 and 5.

Thus, in such a configuration, since the lead wires 10A and 10B are fixed by the through holes 21 provided in the outer core 20, a groove is formed on the outer peripheral surface of the measuring tube 1, an adhesive, Since it is not necessary to fix it with tape or the like, the wiring work of the lead wires 10A and 10B is simple and easy, and it has excellent heat resistance and vibration resistance. Further, when the outer core 20 is arranged on the outer circumference of the measuring tube 1 so that the axis lines of the electrode extraction / lead wire lead-out holes 25, 26 and the axis lines of the electrodes 4A, 4B are aligned, the loops of the lead wires 10A, 10B are formed. Since the surface can be made to coincide with the surface orthogonal to the axis of the measuring tube 1 including the electrodes 4A and 4B, 90 ° noise can be reduced (processing accuracy of the through hole 21 and mounting accuracy of the outer core 20). Should be raised). Furthermore, since the through hole 21 may be formed at the same time as the press molding of the outer core 20, there is no fear that the number of working steps and the number of parts will increase.

In the above embodiment, the outer core 20 is divided into the upper and lower parts and the upper core 20A and the lower core 20B are used. However, the present invention is not limited to this. Of course, it may be formed in a shape.

[0013]

[Effect of device]

 As described above, according to the electromagnetic flowmeter of the present invention, a plurality of through holes are formed on the peripheral surface of the outer core so as to be spaced apart from each other on the line that coincides with the electrode position and is orthogonal to the fluid flow direction. Since the signal lead wire is inserted and fixed in the through hole of, the wiring work of the signal lead wire is easy and the loop surface can be made parallel to the magnetic field of the exciting coil, and the 90 ° phase It is possible to reduce the noise due to the shift. Therefore, the measurement accuracy of the electromagnetic flowmeter can be improved, and since it is only necessary to make a hole in the outer core, the structure is simple and it can be manufactured and provided at low cost, and its practical effects are great. is there.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of an electromagnetic flow meter according to the present invention.

FIG. 2 is a sectional view of the same electromagnetic flow meter.

FIG. 3 is a perspective view of an outer core.

FIG. 4 is a schematic perspective view of a conventional electromagnetic flow meter.

FIG. 5 is a sectional view of the electromagnetic flow meter.

[Explanation of symbols]

 1 Measuring Tube 3A, 3B Exciting Coil 4A, 4B Electrode 5 Pipeline 6A Inner Core 6B Outer Core 7 Converter 8 Lining 10A, 10B Signal Lead Wire 11 Case 12A, 12B Shield Braided Wire 13 Electromagnetic Flowmeter 20 Outer Core 21 Through Hole

Claims (1)

[Scope of utility model registration request] 1. A pair of exciting coils which are provided on the outer circumference of a measuring tube and which form a magnetic field perpendicular to the flow direction of a fluid to be measured,
In an electromagnetic flowmeter having a pair of electrodes arranged to face the measurement tube so as to be orthogonal to both the magnetic field and the flow direction of the fluid, and an outer core arranged outside the pair of exciting coils, A plurality of through-holes are formed on a line on the outer peripheral surface of the outer core that coincides with the electrode position and is orthogonal to the fluid flow direction, and a signal lead wire whose one end is connected to the electrode is inserted into the through-hole. Electromagnetic flowmeter characterized by being fixed by.