JPS5917112A - Electromagnetic flowmeter - Google Patents

Abstract

PURPOSE:To reduce the cost of manufacture, by providing a pair of flexible printed boards which are printed and wired thereon with spiral conductive circuits on the front and lead-out wires on the rear on the outside circumferential part of a measuring tube so as to enclose said measuring tube. CONSTITUTION:A pair of flexible printed boards 4, 5 are mounted on the outside circumferential part of a measuring tube 1 in the state of enclosing the same and maintaining electrical insulation therefrom. The boards 4, 5 are printed and wired on the top surface of the base films with conductive circuits 7 to serve as sources for generating magnetic fields so as to draw a uniform and dense spiral shape. On the other hand, lead-out wires 9 which lead out the intermediate parts of the circuits 7 to the circumferential end edges of the boards 4, 5 are printed and wired on the rear side in order to connect said intermediate parts to the outside. The common use of one kind of the flexible printed boards is thus made possible, and the cost of manufacture is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic flowmeter that measures a single flow rate for production process management, transportation, and the like.

In general, electromagnetic flowmeters use Faraday's electromagnetic induction phenomenon to convert the flow rate of a conductive fluid passing through a measuring tube into an electrical signal and measure it. It has the advantage that it does not cause pressure loss and can also measure the flow rate of mixed flows containing corrosive fluids, slurries, solids, etc., which is difficult to do with other measurement methods. Recently, it has come to be used for flow measurement in all fields, including chemical plants.

On the other hand, as electromagnetic flowmeters become widely used, there is a need to reduce the price of electromagnetic flowmeters, which have the drawback of being expensive.

However, in the conventional electromagnetic flowmeter, it is necessary to manufacture a detector corresponding to each pipe diameter and a coil pattern as a magnetic field generating means corresponding to the detector for pipes having different pipe diameters. This is because the electromotive force generated varies depending on the tube diameter and the strength of the magnetic field even if the flow velocity is the same. For this reason, there is a problem in that the parts are not compatible and the manufacturing cost increases.

The present invention was developed in view of these points, and includes a spiral conductive circuit printed on the outer periphery of the measuring tube on the front surface, and a lead wire connecting the middle part of this conductive circuit to the outside on the back surface. The object of the present invention is to provide an electromagnetic flowmeter that can reduce manufacturing costs by having an extremely simple configuration in which a pair of wired flexible printed boards are provided so as to wrap around the measurement tube. Hereinafter, the configuration and the like will be explained in detail with reference to embodiments shown in the drawings.

FIG. 1 is a perspective view showing an electromagnetic flow chanter according to the present invention. In the figure, the reference numeral 1 is a measurement tube installed in the middle of the flow path piping for the measurement fluid, and on the inner wall thereof, although not shown, there are For example, it is lined with a lining made of an insulating material such as Teflon or neoprene. In addition, on both the left and right sides of this measuring tube 1, there are a pair of electrodes 2.2 (one of which is (not shown) are provided to face each other within the measuring tube 1. A signal line (not shown) is connected to the outer end of these electrodes 2゜2 to electrically connect the electrodes 2, 2 to a terminal in an external connection terminal board 3 installed above the measuring tube 1. has been done.

Reference numeral 4.5 denotes a pair of flexible printed boards installed in a direction perpendicular to the direction of fluid flow and the direction in which the electrodes 2, 2 face each other. They are attached by screws 6, 6, . . . so that they are wound around each other and face each other, and are electrically insulated from the measuring tube 1.

As shown in FIG. 2, these flexible printed boards 4 and 5 have a conductive circuit 7, which serves as a magnetic field generation source, printed on the upper surface of the base film in a uniform spiral shape around a central hole 8. There is.

- On the back side of the blade, in order to connect the middle part of the conductive circuit T to the outside, the middle part is connected to flexible printed boards 4 and 5.
A lead line 9 is printed on the edge of the 0th periphery. Here, Ll is the connecting end of the central base end of the conductive circuit 7;
A is also the terminal connection end, B-Dlj: connection end drawn out from the middle part of the conductive circuit 7 by the lead wire 9, 1
Reference numeral 0 denotes a connection line printed and wired on the back surface of the lexical printed boards 4 and 5 in order to connect the connection end L2 at the center and the connection end 0 at the peripheral edge.

Therefore, the conductive circuit 1 is connected to the flexible printed boards 4 and 5.
The number of turns through which current flows can be changed as appropriate by selecting the connection end provided on the peripheral edge of the wire. That is, when trying to reduce the number of turns in order to generate a strong magnetic field, it is sufficient to connect the connecting end AVr-, and conversely, when trying to reduce the number of turns, the connecting end should be changed from connecting end B to connecting end C2D. Bye.

To explain the connection, the flexible printed board 4 on the upper side near the external connection terminal board 3 is attached to the measuring tube 1 so that the connection ends face each other with the electrode 2 in between, and the flexible printed board 4 is connected to the central connection end L1. L2 is connected to the external connection terminal board 3 by a lead wire (not shown), and the lower 7 lexiple printed board 5
The connecting ends Ll and L2 are connected to each other. Then, as shown in FIG. 3, select the same sign (connection ends B and B in the figure) so that the number of turns of the upper and lower conductive circuits 7 and the direction of the generated magnetic field are equal, and connect the lead wires 11. At the same time, the connecting end 0.0 is similarly connected to the lead wire 11.

In the electromagnetic flow t*+ configured in this way, the conductive fluid in the measuring tube 1 flows perpendicularly to the magnetic field generated by the conductive circuit 1, so the direction of fluid flow and the direction of the magnetic field are different. An electromotive force proportional to the average flow rate is generated between the electrodes 2, which are provided in a direction perpendicular to the flow rate. This is amplified by an amplifier (not shown) to obtain a pointer or pen deflection proportional to the flow rate.

In addition, the number of turns of the conductive circuit 7 printed on the flexible printed boards 4 and 5 can be changed by selecting the connection end as described above, and a magnetic field can be generated that is suitable for measurement tubes with different diameters. I can do it.

In addition, as the materials for the flexible printed boards 4 and 5, polyimide thin plates, epoxy, polyester, etc. can be used. In addition to these) thermosetting resin materials, various materials similar to thermoplastic resin materials such as polyphenylene, oxide, polycarbonate, etc. may be used, including tetrafluoroethylene and trifluorochloroethylene, although they are expensive. .

As explained above, according to the present invention, a flexible printed board with a spiral conductive circuit on the front surface and a lead wire for drawing out the middle part of the conductive circuit on the back surface is connected to the measuring tube in the direction of flow and the electrodes. By selecting the connecting end of the conductive circuit, the number of turns of the conductive circuit corresponding to the diameter of the measuring tube can be determined to generate an appropriate magnetic field and to control the flow rate. Can be measured accurately.

Therefore, the parts for generating the magnetic field, which had to be manufactured for each measuring tube with a different diameter as in the past, can be made common by using a single type of flexible printed board, making it possible to configure an electromagnetic flowmeter. This has the effect of increasing compatibility of parts, which reduces manufacturing costs.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an electromagnetic flowmeter according to the present invention, Fig. 2 is a plan view showing a 7 lexiple printed board which is the main part of the invention, and Fig. 3 is a side view for explaining the connection state. It is a diagram. 1... Measuring tube, 2... Electrode, 4, 5... Flexible printed board, 7φ... Conductive circuit, 9...
・Leader line. Patent Applicant Yamatake Honeywell Co., Ltd. Agent Masaki Yamakawa (and 1 other person) Figure 1 Figure 82 Figure 3 4-28-1 Nishirokugo, Ota-ku, Tokyo Yamatake Honeywell Co., Ltd. Gabao Campus 0 Inventor Ryoichi Matsumoto Yamatake Honeywell Co., Ltd. Kamata Factory, 4-28-1 Nishirokugo, Ota-ku, Tokyo

Claims (1)

[Claims] A conductive circuit drawing a uniform spiral shape is printed on the outer circumference of a measurement tube having a pair of electrodes facing each other in a direction perpendicular to the direction of fluid flow, and an intermediate portion of the conductive circuit is printed on the back surface. A pair of 7 lexiple printed boards on which lead wires are printed for connection to the outside are made to face each other in a direction perpendicular to the direction in which the fluid flows and the direction in which the electrodes face each other, and the measuring tube is connected to the board. An electromagnetic flowmeter characterized by being arranged in a winding manner.