JPS58205815A - Electromagnetic flow meter - Google Patents

Abstract

PURPOSE:To improve the operability in wiring signal lines by using as the signal lines an insulated sheet whereon a signal circuit is wired by printing. CONSTITUTION:A signal circuit 32 which is wired on an insulated sheet 30 by printing and both sides of which are shielded with a non-contact electroconductive leaf film 31 is used as signal lines connecting electrically the terminals 27 and 28 on a terminal board 26 to electrode 15 and 16 respectively. The electroconductive leaf film 31 shielding the signal circuit 32 from both sides thereof is attached on the insulated sheet 30 in the vicinity of both sides of the portions 32a and 32b of the signal circuit, while a part of it is extended to the peripheral end part of a hole 39 for fitting the sheet. According to a constitution described above, the operability in wiring the signal lines can be improved, and simultaneously, noise can be removed by a shield effect brought about by the electroconductive leaf film.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic flowmeter, and in particular to an improvement in a signal line that electrically connects an electromotive force generated between t and t and a terminal provided oppositely to each other in a measuring tube. The flow needle is
This device uses Faraday's electromagnetic induction phenomenon to convert the flow rate of a conductive fluid passing through a measurement tube into an electrical signal and performs the measurement, and there are no moving parts and no pressure loss occurs due to measurement. Another advantage is that it is possible to measure the flow rate of a mixed flow containing corrosive fluids, slurry, solids, etc., which is difficult to do with other measurement methods. As an electromagnetic flow needle having such a function, one having a configuration as shown in FIG. 1 is known. In other words, the symbol 1 in the figure has 7 lunges 1 a% 1 b on both ends.
A measurement tube installed in the middle of a fluid flow path to be measured, the inner wall of which is lined with a lining 2 made of an insulating material such as Teflon or neoprene.
Excitation coils (not shown) that apply a magnetic field perpendicular to the direction of the fluid flow t are disposed on both the upper and lower sides of the measuring tube 1, and the direction of the magnetic field and the direction of the flow n are disposed. A pair of electrodes 3.4 are provided in the measuring tube 1 so as to face each other in directions perpendicular to each other in order to take out the electromotive force generated in the fluid in proportion to the flow velocity. A signal line 6.7 for electrical connection to a terminal in the external connection terminal board 5 installed above the measuring tube 1 is connected to the outer end of 3.4. Each signal line 6.7
is attached to the terminal board 5 side above the measurement tube 1 and is attached in the following state along approximately 1/4 circumference of the outer circumference of the measurement tube 1.

However, according to the electromagnetic flowmeter configured as described above, the cross-sectional area A surrounded by the signal line 6.7 between both electrodes 3.4 and connecting each of these electrodes 3.4 to the terminal board 5 side is two-dimensional. A noise electromotive force is generated due to the 90° phase shift, which is proportional to the magnetic field and depends on the time compensation of the magnetic field, and is transmitted as noise to the transmitter side.

In the conventional method, not only is it necessary to be careful when wiring the signal lines 6 and T in order to minimize such noise, but also the above-mentioned noise removal circuit is required, which reduces work efficiency. Furthermore, this has caused problems in terms of structure.

In addition, the noise caused by the 90° phase PC described above may be caused by the balance of the amplifier of the converter being corrupted due to dirt on the electrodes 3.4, etc., and the noise may become in phase with the signal and be superimposed with the signal, impairing measurement accuracy. Yes, it is necessary to take some measures. For this reason, conventionally, in order to reduce the above-mentioned 90" noise, many wires were manually attached in parallel around the outer circumference of the measuring tube 1, and measurements were taken for each wire to find the one with the least noise. They either do the troublesome work of using one wire as a signal wire, or they use an electrical trimmer to minimize noise, which takes a lot of time and increases costs. Measure r, not invite fool p
In particular,
The above-mentioned conventional electromagnetic flow needle is equipped with a means of inserting a shield tube into each signal line 6, 7 as a countermeasure against external electrical noise, which is a cumbersome process and requires the cloth of the signal line as described above. This puts more strain on line work, and this must also be taken into consideration.

The present invention was made in view of the above-mentioned circumstances.
Use an insulating sheet with printed wiring of the signal circuit as the 4N line, and attach a conductive foil film on both sides of the signal circuit on the insulating sheet, as well as on the sac and the actual image side in a non-contact manner. With this simple configuration, it is possible to greatly improve the work efficiency when wiring the I-α line, and the shielding effect of the conductive foil film can be demonstrated, making it possible to eliminate noise caused by a 90° phase shift. We provide an electromagnetic flowmeter that can be easily and easily made as small as possible, reducing the overall cost and improving the reliability of its measurement accuracy. , the present invention will be explained in detail using embodiments shown in the drawings.

FIG. 2 shows an embodiment of the electromagnetic flow needle according to the present invention. In the figure, first, the schematic structure of the magnetic flow pointer 10 will be briefly described. The measuring tubes 11&, 11b have mounting flanges (see Figure 4) at both ends, and a lining 12 made of an insulating material is attached to the inner circumference of the measuring tube 11.◇ 13.14 15.16 is a pair of saddle-shaped excitation coils disposed opposite to each other on both upper and lower sides of the measurement tube 11; 15.16 is the direction of the magnetic field generated by the excitation coil 13.14 and the direction of the flow of the measurement fluid; In this embodiment, the lining 12 is disposed on the left and right sides of the measuring tube 11 in directions perpendicular to each other. A cylindrical part having a lining part 12a continuous with the electrode 15 is held by this cylindrical part 17 so that its tip is exposed inside the measuring tube 11. , is fixed inwardly of the measuring tube 11 by a pressing spring 19 via a presser plate 1B which is fixed to the cylindrical portion 17 side via screws 18a, 18a. Of course right side electric +Iji16
is also held by a mounting portion having a similar configuration.

20 is a casing-shaped casing that accommodates each of the above-mentioned constituent members, and is provided on the left and right sides of the measurement tube 11.
c' in a position facing the pole 15.16 and the pole part lid body 22.2.
It is blocked by 3. A terminal box 25 is provided on the upper part of the casing 20, and is formed by a rectangular wall 20a rising upward and a terminal cover 24 that closes the opening of the terminal box 25.
A terminal board 26 for external connection is provided in the opening 25a facing inward for sending the detected values by the electrodes 15, 16 to a control section (not shown).

Now, according to the present invention, in the electromagnetic flowmeter having the above-described configuration, the conventional wire can be used as a signal line for electrically connecting the terminals 27.28 on the terminal board 26 and each of the electrodes 15.16. Instead, a No. E circuit 32 was used in which printed wiring was printed on an insulating sheet 30 as shown in FIGS. 3 and 4, and both sides of the wiring were shielded with a non-contact conductive foil film 31. As shown in FIGS. 3 and 4, the insulating sheet 30 is curved in a broken wave shape so as to surround at least half the outer circumference of the measuring tube 11. Electrode fixing side lead pieces 33.34 fixed to the outer end side of the electrode 15.16 are extended and formed on both ends in the winding direction. The signal circuit 32 is printed and wired by gluing, for example, copper foil on the shortest straight axis connecting the male lead pieces 33 and 34.Then, this signal circuit 32 is divided at the center. At the same time, by punching out the central part of the insulating sheet 30 corresponding to each divided portion of the signal circuit 32, the terminal fixing side lead pieces 35, 36 are fixed to the terminals 27, 28 side. 0 is formed,
At both ends of each divided signal circuit 32a, 32d, there are holes 37as, 37b, -38&, 38 for attaching electrodes and terminals.
b is formed.

Further, reference numeral 39 in the figure indicates sheet mounting holes drilled at the four corners of the insulating sheet 30, and as shown in FIG.
It is attached to the outer periphery of the measuring tube 11 by a screw such as 0 or the like.

A conductive foil film 31 (31a) shields the above-mentioned signal circuit 32 (32a, 32b) from both sides.

31b) are attached to the insulating sheet 30 close to both sides of each signal circuit 32aN32k), and a portion thereof extends to the peripheral edge of the sheet attachment hole 39. Therefore, these conductive foil films 31 (31a-,
31b) is grounded to the same potential as the measuring fluid when screwed to the measuring tube 11 via the earthing ring 42 connected via the lead wire 41 from the measuring tube 11 and one of the 7 rank portions 11a. Here, as the material for the insulating sheet 30, various materials similar to thermoplastic resin materials are known. For example, although it is flat, ethylene tetrafluoride is also thermosetting.
A thin plate made of epoxy, ester ester, or polyimide may also be used.

Further, a signal circuit 32 (3) formed on the insulating sheet 30
2a, 32d) Furthermore, the conductive foil film 31 (31a).

It goes without saying that 31b) may be formed on one side of the sheet, or may be sandwiched between two sheets of material.

Furthermore, when it is desired to increase the length of the terminal fixing side lead pieces 35 and 36, modifications such as bending and overlapping the central portions in the longitudinal direction of the insulating sheet 30, or cutting and joining them can be considered.

Then, the conductive foil film 31 (31&,
31b) and signal circuits 32 (32a, 32b) are interposed inside the excitation coil 13 at the outer periphery of the measuring tube 11, as shown in FIGS. 2 and 4. It is sufficient to connect the end lead pieces 33, 34: 35, 36 to the electrode 15, 16 and the terminal 27, 28.

With such a configuration, it is not only possible to perform signal line wiring work much easier than in the past, but also it is possible to appropriately select the best cloth edge position and reduce noise. According to the present invention, a signal circuit 32 (32a, 32b) printed on an insulating sheet (3G) is electrically conductive from both sides thereof. ! iJ1g 31 (31 &, 31 b
), it is possible to exhibit its effect in removing the above-mentioned noise.

Moreover, the signal circuit 32 (32a,
As shown in FIG. , 32
In this case, the surface side of the signal circuit 32 (32a, 32b) on the insulating sheet 30 is provided with a conductive layer through the insulating sheet 52t. Insulating sheet 5 having a transparent foil film 50
3, and an insulating sheet 54 having the same conductive foil film 51t is disposed on the back side so as to sandwich the insulating sheet 30 from both sides. However, the present invention is not necessarily limited to such a structure, and it goes without saying that the insulating sheets 53 and 54 may be omitted. In addition, the signal circuit 32 (32
a, 32b) corresponding to the electrodes 15, 16 and terminals 27, 28, so as to enable electrical connection thereto.
The outer seats 52, 53, and 54 are opened slightly larger.

It should be noted that the present invention is not limited to the structure of the embodiments described above, and it goes without saying that the shape, structure, etc. of each part can be modified and changed as appropriate.

As explained above, when the electromagnetic flow needle according to the present invention is installed, an insulating sheet formed by printed wiring of a signal circuit is used as a signal line, and both sides of the signal circuit on the insulating sheet, furthermore, the front side thereof, Since the conductive foil film is attached to the back side in a non-contact manner, it is possible to greatly improve the workability when wiring signal lines, and also to improve the conductivity even though the structure is simple and inexpensive. The shielding effect of the 9011 phase shift can be minimized due to the shielding effect of the 9011 phase shift, which improves overall workability, reduces costs, and greatly improves the reliability of measurement accuracy. It has various excellent effects such as:

[Brief explanation of drawings]

Fig. 1 is a schematic perspective view showing a conventional electromagnetic flowmeter, Fig. 2 is a cutaway side view of essential parts showing an embodiment of the xi flow needle according to the present invention, and Figs. 3 and 4 are % of the present invention. 12--A developed view and a perspective view of an insulating sheet having a conductive foil film and a signal circuit as a base and a state in which it is installed, and FIG. 5 is a sectional view of a main part of an insulating sheet showing another embodiment of the present invention. 10... Electromagnetic flow needle, 11... Measuring tube 12...
...2 innings, 13.14...a pair of excitation coils, 15.16...a pair of electrodes, 20...kaizon, 25...terminal box, 26...terminal board , 27
．． 28・Φ・Terminal, 30・・φ・Insulation sheet, 31
(31a, 31b)... Conductive foil film, 32 (32a
, 32b)...Signal circuit, 33.34...1i
t1tA Fixed side lead piece, 35.36...Terminal fixed side lead piece, 39...Mounting hole, 40...Screw, 42...Earth ring, 50.51... ...Conductive foil film ◎Patent applicant Yamatake Honeywell Co., Ltd. Representative Masaki Yamakawa (and one other person) Figure 4 32 Continued from page 1 0 Inventor Sakae Ishiyo 4-28 Nishirokugo, Ota-ku, Tokyo No. 1 Yamatake Honeywell Co., Ltd. Kamata Factory 0 Inventor Ryoichi Matsumoto No. 4-28-1 Nishirokugo, Ota-ku, Tokyo Inside Yamatake Honeywell Co., Ltd. Kamata Factory

Claims (2)

[Claims] (1) An insulating sheet is placed around the measuring tube to measure the flow rate of the measuring fluid with electrodes facing each other. an electrode fixing means fixed to the electrode of the measuring tube; a signal circuit printed on the insulating sheet on the shortest straight axis connecting both pole fixing means; and a central part of the signal circuit. When the signal ?s is constituted by a terminal board fixing means provided for each circuit of the circuit divided by f'L7'c and fixed to the terminal board for external connection, the signal is formed on the insulating sheet. An electromagnetic device characterized in that a conductive foil film is attached to both sides of the circuit so as to be close to each other in a non-contact state, and a part of the conductive foil film is grounded through a measurement tube to which an insulating sheet is attached. flow needle. (2) Measurement in which the flow rate of the fluid to be measured is measured using electrodes facing each other, an insulating sheet is provided surrounding at least half of the outer circumference of the tube, and an insulating sheet is provided on both ends of the insulating sheet in the winding direction. An electrode fixing means fixed to each electrode of the measuring tube, an f"1.711 signal circuit printed on the shortest straight axis connecting both electrode fixing means on the insulating sheet, and a central part of this signal circuit. A terminal board fixing means provided at each divided part of the signal circuit and fixed to the external connection terminal board constitutes a signal line, and is close to both sides of the signal circuit on the insulating sheet in a non-contact state. A conductive foil strip is attached so that a part of the strip is grounded through the measurement tube to which the insulating sheet is attached, and the signal circuit on the insulating sheet is covered from behind in a non-contact manner from the back side. An electromagnetic flow needle characterized in that the insulating sheet is sandwiched between foil films.