JPS6210650Y2 - - Google Patents

Description

Detailed Description of the Invention This invention relates to an electromagnetic flowmeter, and is an improvement to protect the electrodes inserted into the conduit from electrochemical influences and to obtain a stable potential.

1 and 2 show an interpolated electrode 1 and an extrapolated electrode 3 inserted into a conduit of an electromagnetic flowmeter according to the prior art. The internal electrode 1 shown in FIG. 1 is installed by being inserted into the insertion hole 9 from inside the conduit 5, and the tip of the electrode body 1a is in contact with the inner peripheral surface of the lining material 7. A flange portion 1b is provided, and a pointed liquid contact portion 1c is provided at the center of the surface of the flange portion 1b so as to face the internal space of the conduit 5. Furthermore, the flange portion 1
A cover 2 made of an insulating material is fitted around the outer periphery of b. In addition, 1d in the figure is a signal lead wire extraction part.

In such an internal insertion type electrode 1, the electrode main body 1a is inserted into the insertion hole 9 from inside the conduit 5, and the electrode chamber plug 11 is inserted through the spring 10 with the flange portion 1b in contact with the lining material 7. It is fixed within the electrode chamber 12 by fastening. However, with the internal electrode 1, the cover 2 may peel off depending on the slurry liquid flowing into the conduit 5, or the wetted part 1 may peel off.
There is a drawback that c is easily worn out.

Therefore, an extrapolation type electrode 3 shown in FIG. 2 is generally used. Extrapolation type electrode 3 shown in Figure 2
is of a type that is installed by being inserted into the insertion hole 9 of the conduit 5 from the outside of the conduit 5, and has a flange part 3b in the middle of the electrode body 3a, and a liquid contact part 3c at the tip of the electrode body 3a. A signal lead wire extraction portion 3d is formed at its base end. This external type electrode 3 is inserted into the insertion hole 9 from the outside of the conduit 5 so that the liquid contact part 3c faces the internal space of the conduit 5,
It is fixed in the electrode chamber 12 by fastening the electrode chamber plug 11 with the flange portion 3b in contact with the electrode seal portion 8 with the spring 10 interposed.
This externally inserted type electrode not only can be easily replaced from the outside of the conduit, but also has the advantage that the volume protruding into the internal space of the conduit can be reduced. However, a problem arose in that the zero point of the electromagnetic flowmeter became extremely unstable after flowing the measuring liquid into the conduit.

Therefore, the inventor of the present invention made extensive studies to solve this problem and found that the zero point becomes unstable due to the following cause.

The insertion hole 9 into which the electrodes 1 and 3 are inserted is inserted through the hole 6 provided in the conduit 5 as shown in FIG. A lining is formed of a lining material 7 over the outside of the conduit 5 in the electrode chamber 12 . However, even in such an insertion hole 9, the electrode inserted into the insertion hole and the electrode seal portion 8 in FIG.
Since there is a small gap between the two, air will initially exist in this gap. Therefore, when this conduit is connected to piping and the measured fluid is flowed through the pipe, the measured liquid and the above air are gradually replaced in this gap, and eventually the entire gap is filled with the measured liquid. . Furthermore, even after this gap is filled with the liquid to be measured, the flange part 3b side of the electrode seal part 8 in FIG. In such a case, the gap created between the liquid contact side of the electrode seal portion 3b and the liquid contact side of the electrode 3 changes, and the measurement fluid is replaced. As a result, it has been found that as the measurement liquid and air are replaced, or the measurement fluids are replaced with each other, the electrochemical noise generated between them changes and the voltage taken out from the electrode becomes unstable.

Therefore, based on this knowledge, the present invention was developed as follows: ``An electrode seal part is formed extending from the hole drilled in the conduit to the outside of the conduit, and a lining material is provided to line the inner peripheral surface of the conduit. An electromagnetic flowmeter comprising an insertion hole provided in the hole with the seal part interposed therebetween, and an electrode inserted into the insertion hole so that the liquid contact part faces the internal space of the conduit,
The above problem is solved by arranging that at least the outer peripheral surface of the electrode facing the insertion hole is covered with an insulating material.

Embodiments of the present invention will be described in detail below with reference to the drawings. In this embodiment, a case will be described in which the electrodes inserted into the electromagnetic flowmeter are extrapolation type electrodes. Note that the same numbers are given to the same members as before.

As shown in FIG. 3a, the electrode 20 of this embodiment has a liquid contact part 20c at the distal end of the electrode body 20a, a signal lead wire extraction part 20d at the proximal end, and a middle part of the electrode body 20a. A flange portion 20b is provided at the flange portion 20b, and the entire outer peripheral surface except for the liquid contact portion 20c and the signal lead wire extraction portion 20d is coated with an insulating material 21.

In such an electrode 20, even if it is inserted into the conduit 5 and the inside of the conduit 5 is filled with liquid, since the outer peripheral surface of the electrode 20 is coated with the insulating material 21, the electrode body 20a and the electrode seal portion 8 It is not affected by electrochemical noise caused by the displacement phenomenon of air and liquid that occurs in the gap between the In addition, it is possible to reliably prevent insulation deterioration of the electrodes due to the liquid leaking from the sealing surface 24 of the flange portion 20b and the deterioration of the electrode insulation caused by condensation of moisture in the air. the result,
A stable potential can be obtained from the electrode 20.

In addition, FIG. 3b shows an electrode 22 in which the liquid contact part 22c is formed into a pointed shape, and in this case, the insulating material 21 is coated on the outer peripheral surface excluding the liquid contact part 22c. has been done. Even with such an electrode 22, the same effects as in the above embodiment can be obtained.

FIG. 4 shows another embodiment. As shown in the figure, in this embodiment, only the surface portion of the electrode 23 in contact with the electrode seal portion 8 of the conduit 5 is coated with an insulating material 21. In other words, the surface area that contacts the electrode seal part 8 when the electrode is inserted, excluding the liquid contact part 23c at the tip of the electrode body, that is, the insulating material extends from the outer peripheral surface of the electrode main body 23a to the sealing surface 24 of the flange part 23b and its outer peripheral surface. It was coated with No. 21. Note that if liquid does not enter between the lining material of the electrode seal portion 8 and the seal surface 24 of the flange portion 23b of the electrode 23, the coating of the seal surface 24 may be omitted as shown in FIG. In this embodiment, it is possible to obtain the same effect as the above-mentioned embodiment, and it is also economical.

In each of the above embodiments, the case where the electrode surface is coated has been described, but if necessary, the electrode surface may be covered with a means of adhering and press-molding an insulating material.

As specifically explained above with reference to the embodiments, according to the present invention, at least the outer circumferential surface of the electrode that is inserted into the insertion hole around which the electrode sealing part is formed with the lining material contacts the electrode sealing part. Since the electrode is coated with an insulating material, it is not adversely affected by electrochemical noise caused by the displacement phenomenon of air and liquid that occurs in the gap between the electrode body and the electrode seal. As a result, a stable potential is obtained from the electrodes, which stabilizes the zero point of the electromagnetic flowmeter and improves accuracy. In addition, because it is almost unaffected by liquid leaking from the sealing surface of the flange or condensation of moisture in the air, it prevents the insulation resistance of the electrode from decreasing and maintains high accuracy, making it extremely superior. It has many advantages.

[Brief explanation of the drawing]

Figures 1 and 2 relate to conventional examples; Figure 1 is a longitudinal sectional view showing an internally inserted electrode inserted into a conduit; Figure 2 is a vertical sectional view showing an externally inserted electrode; Figures 3a and 3b are longitudinal sectional views showing an extrapolation-type electrode in which the liquid-contacted part has a planar shape and a pointed shape, according to one embodiment of the present invention, and Fig. 4 is an extrapolation according to another embodiment. FIG. 5 is a longitudinal sectional view of an electrode according to another embodiment. In the drawing, 5 is a conduit, 6 is a hole, 7 is a lining,
8 is an electrode seal part, 9 is an insertion hole, 10 is a spring, 1
1 is an electrode chamber plug, 12 is an electrode chamber, 20, 22, 23
is an electrode, 20a, 22a, 23a are electrode bodies, 2
0b, 22b, 23b are flange parts, 20c, 2
2c, 23c are wetted parts, 20d, 22d, 23d
21 is a coated insulating material, and 24 is a sealing surface of the electrode flange.

Claims (1)

[Scope of utility model registration request] An electrode seal part is formed extending from a hole drilled in the conduit to the outside of the conduit, and a lining material is provided on the inner peripheral surface of the conduit, and the electrode seal part is provided in the hole with the seal part interposed therebetween. In the electromagnetic flowmeter, the electromagnetic flowmeter is equipped with an insertion hole that is inserted into the insertion hole, and an electrode that is inserted into the insertion hole so that the liquid contact part faces the inner space of the conduit, at least the outer circumferential surface of the electrode facing the insertion hole is An electromagnetic flowmeter characterized by being covered with an insulating material.