JPH0554885B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for manufacturing electrodes for an electromagnetic flowmeter, and more particularly to a method for manufacturing electrodes for an electromagnetic flowmeter in which electrodes are formed on a ceramic tube.

<Prior Art> FIG. 3 shows the structure of an electrode formed by a conventional electromagnetic flowmeter electrode manufacturing method.

Reference numeral 10 denotes a tube body of an electromagnetic flowmeter, which is made of, for example, insulating ceramics. The electrode portion 11 is formed integrally with the tube body 10 by dispersing conductive powder 12 therein.

FIG. 4 is a block diagram showing a procedure for forming electrodes using another electrode manufacturing method for a conventional electromagnetic flowmeter.

In FIG. 4A, 13 is a tube made of ceramics. An electrode hole 14 is made in the position where the electrode is to be formed in the tube body 13, and an electrode 15 formed into a cylindrical shape by mixing ceramic powder and a conductive substance is inserted into the hole, and the tube body 13 and the electrode 15 are simultaneously connected. Sinter. Gap 1 between tube body 13 and electrode 15
If the number 6 is appropriately selected in consideration of the shrinkage rate during sintering, the tube body 13 and the electrode 15 will come into contact and be fixed as shown in FIG. 4B.

<Problems to be Solved by the Invention> However, with the electrode manufactured by the conventional electrode manufacturing method shown in Fig. 3, although the degree of adhesion between the tube and the conductive powder is good, it is difficult to accurately position the electrode part. wisely,
In addition, with the electrode made using the conventional electrode manufacturing method shown in Figure 4, the electrode can be positioned correctly, but the ceramics in the tube and electrode are hardly sintered and the interface between the electrode and tube is airtight. difficult to secure. Furthermore, it is difficult to hold the inner surface of the tube (liquid-contacting side) and the surface of the electrode on the same plane for sintering, and there is a drawback that a step is required to make these surfaces the same after sintering.

<Means for Solving the Problems> In order to solve the above-mentioned problems, the present invention makes holes at electrode positions in a ceramic molded body that becomes a tube, and inserts conductive powder to form the electrodes into the holes. After being put into the hole, the powder is pressure-molded in the hole so that it comes into close contact with the inner surface of the hole, and then fired.

<Example> Hereinafter, an example of the present invention will be described based on the drawings. FIG. 1 is a process diagram showing the steps of the electrode manufacturing method of the present invention.

A hole 17 for electrode formation is made in the tube body 13,
A stopper 18 is fixed to the liquid-contacted side so as to abut along the inner surface of the tube body 13. A conductive powder 19 forming an electrode is placed in the hole 17 covered by the stopper 18 .

Next, as shown in FIG. 1B, the powder 19 is pressure-molded using the rod 20 in the direction of the arrow. At this stage, the inner surface of the hole 17 and the powder 19 are in close contact with each other, and the liquid contact surface side 21 of the powder 19 is flush with the inner surface of the tube 13.

Here, a mixture of alumina and platinum in a volume percentage of 1:1 is used as the powder, and the tube body 13 is made of alumina, and the rod 20 is molded and fired at an electrode molding pressure P of 0.5 tons/ ^cm2 . According to the experiment, the tube 13 and the powder 19 were well sintered with each other, and good airtightness could be ensured. Further, even after sintering, the inner surface of the tube 13 and the liquid contact side 21 of the powder 19 are flush with each other, so there is no need for post-processing.

FIG. 2 shows the configuration of an electrode section when detecting a signal voltage via capacitance. In this embodiment, ceramic insulating powder 2 is placed at the bottom of the hole 17.
2 first, then conductive powder 19 is added on top of it.
are inserted in the same manner as shown in FIG. 1 to form the electrode portion 23.

Note that the powder 19 is formed by mixing alumina and platinum powder, but the mixing ratio can be changed arbitrarily.

In addition, in the above explanation, the tube was made of ceramics and the electrodes were made of a mixture of alumina and platinum powder.
It is not limited to this.

<Effects of the Invention> As described above in detail with the embodiments, according to the present invention, the position of the electrode part can be accurately determined, and the tube body and the conductive powder are in close contact with each other, resulting in a good condition. Airtightness can be ensured.

[Brief explanation of drawings]

Fig. 1 is a process diagram showing one embodiment of the present invention;
The figure is a block diagram showing another embodiment of the present invention, FIG. 3 is a block diagram showing the structure of a tube manufactured by a conventional electrode manufacturing method, and FIG. 4 is a block diagram showing a tube body manufactured by another conventional electrode manufacturing method. FIG. 2 is a configuration diagram showing the configuration of a tube body. 10, 13... tube body, 11, 23... electrode part,
12... Conductive powder, 14... Electrode hole, 15...
Electrode, 16... Gap, 19, 22... Powder.

Claims (1)

[Claims] 1 A hole is made at the electrode position of the ceramic molded body that will become the tube, and conductive powder forming the electrode is put into the hole, and then the powder is tightly attached to the inner surface of the hole within the hole. A method for producing electrodes for electromagnetic flowmeters, which is characterized by press-forming and firing so as to produce the electrodes.