JPS61254821A - Electromagnetic flowmeter - Google Patents

Abstract

PURPOSE:To intercept electric noise and to perform stable measurement by metallizing the outside periphery of a measuring pipe 1 made of ceramic with conductive material. CONSTITUTION:The outside periphery of the measuring pipe 1 made of ceramic is metallized with the conductive material 3. the outside periphery of the measuring pipe 1 is wired with a couple of exciting coils and connected with a lead wire led to a lead wire wiring part 2. The whole is covered with a metallic case. Hereby, the electric noise is intercepted and the stable measurement is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electromagnetic flow needle whose measuring tube is made of ceramic.

[Conventional technology]

Electromagnetic flowmeters use Faraday's electromagnetic induction phenomenon to measure flow rates by converting the flow rate of a conductive fluid passing through a measurement tube into an electrical signal, and there are no moving parts during measurement. Not only does it have the advantage of not causing pressure loss due to the precision of the measurement, but it is also possible to measure the flow rate of corrosive fluids, fluids containing slag, solids, etc. that are difficult to measure with other measuring devices. Conventionally, measurement tubes for this type of electromagnetic flow have been made of stainless steel and have an inner surface covered with an insulating lining, but in recent years At, which is a non-conductive material, has been widely used in various fields. ,
A type of electrode made of ceramic has been developed, and has many advantages such as excellent corrosion resistance, no deformation even when used at high temperatures, the ability to cast electrodes, and good electrode sealing. Since then, it has come to be widely used.

[Problem that the invention seeks to solve]

However, although such ceramic measurement tubes have many features, they also have the disadvantage of being susceptible to electrical noise, so conventionally, as a shielding measure, the outer periphery of the measurement tube has been covered with a metal shield plate. Although,
In this case, there is a high risk that the shield plate and the electrode will come into contact with each other in an unexpected situation such as a fixing band loosening during use, resulting in insulation deterioration, and there is also a large number of parts (
I don't like it.

[Means for solving problems]

In order to solve these problems, in the present invention, the outer periphery of the ceramic measuring tube is metallized with a conductive material.

[For production]

With this configuration, electrical noise is blocked and the measurement tube and the conductive material are firmly integrated.

〔Example〕

1 and 2 show an embodiment of the electromagnetic flowmeter according to the present invention, FIG. 1 is a perspective view of a measuring tube, and FIG. 2 is an A of FIG. 1.
It is an A sectional view. In the figure, a measuring tube 1 is formed into a cylindrical shape having seven flange 1a at both ends, and is used by connecting the seven flange 1a on both sides to a conduit (not shown). A pair of excitation coils (not shown) wound in a saddle shape are disposed facing each other on the outer periphery of the measurement tube, and the reference numeral 2 is a lead wire wiring section for the excitation coils. .

The measuring tube 1 is formed by firing At and Os ceramics, but before firing, a conductive paste such as copper is applied to the outer periphery except for the 7 flange 1a. At the same time as firing, this copper paste or the like is metallized on the outer peripheral surface of the measuring tube 1, so that it is firmly integrated with the measuring tube 1. 3 shows a conductive layer made of metallized copper paste. In addition,
During firing, the lead wire wiring portion 2 is skinned to prevent it from being covered with the conductive layer.

With the above configuration, a pair of excitation coils are wired around the outer periphery of the measurement tube 1, guided to the lead wire wiring section 2, connected with the IJ-wire, and then covered entirely with a metal case. The Yoshimi magnetic current positioning needle is completed. When the flanges 1a on both sides of this electromagnetic flowmeter are connected to pipes to allow fluid to pass through, the flow rate of the fluid is converted into an electrical signal and the flow rate is measured. During such flow rate measurement, electrical noise is generated as described above, but the noise is blocked by forming a conductive layer made of copper paste metallization around the outer periphery of the measuring tube 1.

〔Effect of the invention〕

As is clear from the above description, in the electromagnetic flowmeter according to the present invention, the outer periphery of the ceramic measuring tube is metallized with a conductive material.

Not only does it maintain the characteristics of a ceramic measurement tube, but even if electrical noise occurs, it is blocked by the conductive layer made of metallization, making it possible to perform extremely stable measurements, and it is not as effective as a conventional metal shield plate. It is safe because there is no risk of the guiding part separating and causing poor insulation, and it is preferable in terms of inventory control since the number of parts does not increase.

[Brief explanation of drawings]

1 and 2 show an embodiment of the electromagnetic flowmeter according to the present invention, FIG. 1 is a perspective view of a measuring tube, and FIG. 2 is an A of FIG. 1.
It is an A sectional view. 1... Measuring tube, 3... Conductive layer by metallization,

Claims (1)

[Claims] An electromagnetic flowmeter characterized by a ceramic measuring tube whose outer periphery is metallized with a conductive material.