JPS59168323A - Electromagnetic flowmeter - Google Patents

Abstract

PURPOSE:To cope with various fluids having corroding property, by forming an electrode with conductive plastics, and fusing and connecting the periphery of the end part of the electrode and the edge of an electrode inserting hole in a lining so as to provide a unitary body. CONSTITUTION:An electrode 9 is formed by conductive plastics. The periphery of the end part of an electrode inserting hole 4 and the edge of the electrode inserting hole of a lining 2 are fused and connected so as to form a unitary body. In this case, the conductive plastic material is formed by mixing a conductive material such as carbon, aluminum, and copper into plastics as a secondary material, and the property of the plastics is changed into conductive. Therefore, the conductive plastic material is softened and fused at the same temperature as that for insulating plastics forming the lining 2, and both plastic materials are mixed together. In this constitution, corrosion resistance can be increased in comparison with metal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electromagnetic flowmeter used in production processes, transportation management, and the like.

[Prior art]

In general, electromagnetic flowmeters utilize Faraday's law of electromagnetic induction, that is, a voltage is generated in a conductor that moves perpendicularly across a uniform magnetic field. The electromotive force proportional to the average flow rate generated in the magnetic field is extracted and measured using an electrode provided in a direction perpendicular to the direction of the flow and the direction of the magnetic field. This electromagnetic flowmeter has the advantages of having no moving parts, no pressure loss during measurement, and the ability to measure the flow rate of mixed flows containing slurry, solids, etc. Since then, it has been used for flow measurement in all fields.

By the way, in an electromagnetic flowmeter, in order to prevent short circuits and accurately measure the electromotive force generated in the fluid, it is necessary to electrically insulate the fluid. The inner peripheral surface of the formed measuring tube 1 is lined with a lining 2 made of an insulating plastic such as Teflon. An electrode 3 for measuring the electromotive force generated in the fluid passes through the measurement tube 1 in the radial direction and extends through the lining 2.
is inserted into the electrode insertion hole 4 of. This electrode 3 is made of a corrosion-resistant metal suitable for the type of fluid, such as 5US316, Hastelloy, titanium, tantalum, platinum, zirconium, etc., and is supported by a spring member 7 interposed between an insulating member 5 and an electrode holding plate 6. It is loaded with bullets. This is to compensate for deformation of the seal portion due to bone fracture, and the electrode valve plate 6 is attached to the measuring tube 1 with attachment screws 8, 8.

However, in conventional electromagnetic flowmeters of this type, the electrode 3 must be elastically mounted in order to seal the lining 2 and the electrode 3, which not only results in a complicated structure, but also prevents fluid from leaking because a good seal cannot always be achieved. There was a problem in that it was not possible to prevent this.

Another disadvantage is that electrodes 3 made of various metal materials must be prepared for the fluids to be measured.

[Summary of the invention]

The present invention was developed in view of these circumstances, and has an extremely simple structure in which the electrode is formed from conductive plastic and the lining into which the electrode is inserted is welded. The purpose of the present invention is to provide an electromagnetic flowmeter that can handle various types of fluids. Hereinafter, the configuration and the like will be explained in detail with reference to the embodiment shown in the drawings.

〔Example〕

FIG. 2 is a cutaway view showing an electromagnetic flowmeter according to the present invention. In the figure, members that are the same or equivalent to those shown in FIG. The electrode 9 is inserted into the electrode insertion hole 4 of the nine-piece lining 2, and the electrode 9 is made of conductive plastic material, which is different from metal. This conductive plastic is made by mixing plastic with conductors such as carphone, aluminum, and copper as secondary materials to change its properties to conductivity.
It softens and melts at the same temperature as the insulating plastic that makes up the material, making them compatible with each other. In this embodiment, the main raw material resin for the insulating plastic is Teflon, and a mixture of this Teflon and carbon fiber as an auxiliary material is used for the conductive plastic. 10.10...
. . . is a welded portion, where the periphery of the tip end of the electrode 9 and the radially protruding periphery of the electrode 9, the inner opening edge of the electrode insertion hole 4 of the lining 2, and the opening edge of the outside (il) are heated. 11 is a lead wire for taking out a signal, and 12 is the lead wire 11 and the electrode 9.
This is a screw that is screwed onto the electrode 9 in order to connect it to the electrode 9.

In the electromagnetic flowmeter configured as described above, since the electrodes 9 are made of conductive plastic, the electromotive force generated in the fluid to be measured can be transmitted to the lead wire 11 through the electrodes 9. Corrosion resistance can be increased compared to electrodes. Further, by welding the electrode 9 and the lining 2 together, the electrode 9 can be integrated with the lining 2.

FIG. 3 is a sectional view of a main part showing another embodiment. In this embodiment, an electrode valve plate 13 is provided in order to measure a fluid with a high internal pressure of, for example, several tens of kg/crI. This electrode valve plate 13 is an electric '@! , 9 prevent the insulating member 1 from coming out from the lining 2 due to the internal pressure.
It is attached to the measuring tube 1 by a mounting screw 15 so as to press the electrode 9 through the electrode 4 .

Therefore, in the electromagnetic flowmeter configured in this way, corrosion resistance can be increased, the electrode 9 can be integrated with the lining 2, and the flow rate measurement of high pressure fluid can be avoided. I can do it.

Note↑[I! 9 and this? Screw 12 screwed into F+i9
Of course, a highly conductive liquid, ie, contact oil, may be infiltrated into this threaded portion in order to reduce the contact resistance.

Furthermore, in the above embodiments, the insulating plastic and the conductive plastic are made using Teflon as the main raw material resin, but the present invention is not limited to this.
Needless to say, any plastic that melts at the same temperature and is compatible with each other is sufficient.

〔Effect of the invention〕

As explained above, according to the present invention, since the electrode is made of conductive plastic, corrosion resistance can be increased compared to metal, and by welding the N electrode and the lining, they can be integrated. be able to.

Therefore, it is possible to deal with various corrosive fluids, and since there is no sealing part, there is an effect that fluid leakage can be prevented. Furthermore, since there is no need to prepare various electrodes corresponding to the fluid to be measured unlike in the past, it is also possible to expect the effect of reducing manufacturing costs.

[Brief explanation of drawings]

Fig. 1 is a cutaway diagram showing a conventional electromagnetic flowmeter, Fig. 2 is a cutaway diagram showing an embodiment of the electromagnetic flowmeter according to the present invention, and Fig. 3 is a sectional view of main parts showing another embodiment. be. 1e...Measuring tube, 2...Fist lining, 4...
Electrode insertion hole, 9... Electrode, 10... Welding part. Patent applicant Yamatake Honeywell Co., Ltd. Agent Masaki Yamakawa (and one other person)

Claims (1)

[Claims] In an electromagnetic flowmeter equipped with a measuring tube whose inner peripheral surface is lined with a lining made of insulating plastic and through which electrodes are pierced in the radial direction, the electrodes are formed of conductive plastic, and the ends of the electrodes are An electromagnetic flowmeter characterized in that a peripheral edge and an electrode insertion hole edge of the lining are welded.