JP3329193B2 - Manufacturing method of electromagnetic flowmeter measurement tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic flowmeter measuring tube for applying a magnetic field to a measuring fluid to extract an electromotive force generated in accordance with the flow rate of the measuring fluid through a detection electrode or grounding the measuring fluid. In particular, the present invention relates to a method for manufacturing an electromagnetic flowmeter measurement tube improved so as to be highly resistant to flow noise and to improve sealing performance.

[0002]

2. Description of the Related Art Generally, when a measurement fluid flows in contact with a detection electrode, a noise voltage which increases at a low frequency called a flow noise is generated due to a potential formed between the electrode and the measurement fluid. Also, the ground electrode is more susceptible to flow noise if its liquid contact area is small. Less than,
The detection electrode and the ground electrode are collectively referred to as a detection electrode or the like.

The flow noise tends to increase as the conductivity decreases, and to increase as the detection electrode and the like decrease. Further, the flow noise increases when the liquid contact surface of the detection electrode or the like does not match the inner surface of the conduit.

In order to prevent the detection electrode from projecting to the inner surface of the conduit with a curvature corresponding to the diameter, conventionally, the liquid contact surface of the detection electrode is processed into a curved shape and fixed for each diameter. Have been done.

[0005]

However, in the above-described method of manufacturing a measuring pipe for an electromagnetic flowmeter, first, the liquid contact surface of a detection electrode or the like is processed to be flush with the curvature of the measuring pipe. Is difficult, and it is necessary to make many types of detection electrodes in accordance with the difference in diameter due to the difference in diameter.

Second, since the material of the lining is different from that of the detection electrode, it is difficult to perform the same process by cutting or the like, and a mold for each diameter is required to manufacture the measuring tube. There is trouble to become.

[0007]

According to the present invention, as a main structure for solving the above-mentioned problems, a conductive material is integrated with a part of an insulating material and concentrated on a central axis of the insulating material.
A forming step and the molded mold of rod-shaped into a rod with pincushion shape for molding the external shape of the previous insulating material in a direction perpendicular to the columnar, the direction of the center axis of the columnar molded body, the measuring tube
A step of piercing with different hole diameters corresponding to the diameter of the above, wherein the portion of the previous insulating material is used as the lining, and the portion of the previous conductive material is used as the detection electrode or the ground electrode. .

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a process chart showing a molding step of the manufacturing method according to the present invention. Reference numeral 10 denotes an insulating material, for example, plastics such as polypropylene, polyphenylenesulfite, and polysulfone, or ceramics such as alumina. In addition, FIG.
The description up to FIG. 5 focuses on the detection electrodes.

Although not shown, the insulating material 10 is housed in a normal annular split mold so as to be dividable and formed into a cylindrical shape. At this time, the insulating material 10 is housed in the split mold. At this time, the conductive material 11 is integrated with a part of the insulating material 10 in a direction perpendicular to the axial direction of the split mold and molded into a rod shape.

As the conductive material 11, for example, conductive plastics in which a conductive material such as carbon powder, carbon fiber, or metal fiber is mixed into the same material as the insulating material 10, or the same as the insulating material 10 is used. Is formed by using a cermet or the like obtained by mixing platinum powder with the above material.

Further, the rod-shaped mold in this case is formed so that the conductive material 11 is formed in a pin-shaped shape which is concentrated on the center axis of the annular split mold, that is, the center axis of the cylindrical insulating material 10. I do.

Thereafter, the process shifts to the perforation step shown in FIG.
In the molding process, the molded product molded into a columnar shape with the insulating material 10 together with the conductive material 11 has a center axis portion which is bored in the axial direction.

When the insulating material 10 is pierced, it becomes a tubular measuring tube 12, and the conductive material 11 becomes the detecting electrode 13,
14, the inner surface of the measuring tube 12 is provided with the detecting electrodes 13, 1
4 is the same as the liquid contact surface.

In this case, the diameter of the hole to be pierced differs according to the diameter of the measuring tube. However, since the hole has a thread-wound shape in which the conductive material 11 is concentrated on the central axis of the insulating material 10, the diameter is small. As D increases, the area of the detection electrode appearing on the inner surface also increases.

Through the above steps, the part of the insulating material 10 is used as an insulating measuring tube, and the part of the conductive material 11 is used as a detecting electrode having conductivity. Can be manufactured.

As described above, the lining and the detection electrode can be formed integrally with each other, so that the confidentiality is excellent. In addition, since the liquid contact surface of the detection electrode can be formed to be the same as the inner surface of the insulating material 10, the influence of flow noise is reduced. can do.

In the molding step shown in FIG. 1, when molding is performed using plastics as the insulating material 10, heat removal at the center is delayed as compared with that at the periphery, and thermal stress or distortion may remain. If there is a property, a small heat removal hole 15 is preferably opened in the center as shown in FIG. 3, but in this case, the conductive material 11 is
7 is separated.

FIG. 4 shows another manufacturing process in which the arrangement of the conductive material is changed. In this case, two conductive materials 19 and 20 are formed in a rod shape at a predetermined angle from each other so as to intersect at the center axis of the molded body, and two pairs are formed in the molding process shown in FIG. Are formed when the detection electrodes are formed.

When a plurality of pairs of detection electrodes are used as described above,
Although it is possible to reduce the flow rate error detected when the profile of the flow of the measurement fluid is disturbed, it is particularly effective for realizing a small diameter with no extra space.

The present manufacturing method is also effective when forming a detection electrode that is long in the tube axis direction. The detection electrode having such a structure has a large liquid contact area, and thus has an effect of reducing flow noise. is there. The shape of the conductive material is not limited to a square or a triangle.

FIG. 5 is a process chart showing a molding step in which a part of the manufacturing method is further improved. In addition to the conductive material 11 formed as a detection electrode, a configuration of a conductive material 21 formed as a ground electrode for fixing the potential of the measurement fluid at a reference potential is added.

The conductive material 21 is perpendicular to the direction of the rod-shaped conductive material 11 and is
Up and down with respect to the position where 1 is formed (up and down with respect to the paper surface)
A pair is formed in the insulating material 10 at the position shown in FIG.

FIG. 6 shows the types of arrangement positions of the rod-shaped conductive material. The arrangement shown in FIG. 5 corresponds to the C plane when the arrangement shown in FIG. 6 is explained. Alternatively, it can be formed on the A surface or the B surface.

The plane A shows a case where a pair of rod-shaped conductive materials 22 (the other conductive material is not shown) are formed in the same direction as the conductive material 11. Although not shown, at least one bar-shaped conductive material can be formed on the surface B in a direction perpendicular to the conductive material 11.

[0025]

As described above, according to the first aspect of the present invention, a conductive material is integrally molded with a part of an insulating material to form a rod. This rod-shaped mold is manufactured by a perforation process of perforating in the direction of the central axis of the columnar molded body through a molding process of molding the outer shape of the insulating material into a column shape at right angles, so that the liquid contact surface is flat. It is possible to manufacture a measuring tube which is excellent in confidentiality.

Further, since so as to form a rod-shaped conductive material into yarn-like shape to focus on the central axis of the molded article, it is possible to form the size of the detection electrode correspondingly to the size.

Further, according to the third aspect of the present invention, the two conductive materials are formed in a rod shape at a predetermined angle to each other so as to intersect with the center axis of the molded body.
It is possible to manufacture a measurement tube having a plurality of detection electrodes with a flat liquid contact surface and excellent confidentiality, and also to reduce a profile error of a measurement fluid. In addition, Claim 4,
The invention described in the fifth aspect is basically the same as the effect described in the first aspect.

[Brief description of the drawings]

FIG. 1 is a process chart showing a molding step of a manufacturing method according to the present invention.

FIG. 2 is a process chart showing a molding step of the manufacturing method according to the present invention.

FIG. 3 is a process chart showing a molding step in which a part of the manufacturing method shown in FIG. 1 is improved.

FIG. 4 is a process chart showing a molding step in which the configuration of the manufacturing method according to the present invention is changed.

FIG. 5 is a process chart showing a molding step in which a part of the manufacturing method shown in FIG. 1 is further improved.

FIG. 6 is an arrangement diagram showing types of arrangement of a rod-shaped conductive material shown in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Insulating material 11, 21, 22 Conductive material 12 Measuring tube 13, 14 Detection electrode

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-14122 (JP, A) JP-A-63-81214 (JP, A) JP-A-1-221619 (JP, A) 64118 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) G01F 1/58

Claims (5)

(57) [Claims] A conductive material is integrated with a part of an insulating material, and is molded into a rod shape in a pin-shaped shape concentrated on a central axis of the insulating material, and the insulating material is formed in a direction perpendicular to the rod-shaped mold. a shaping step of shaping the outer shape of the material in a columnar shape, the direction of the center axis of the columnar molded body, against the bore of the measuring tube
And a piercing step of piercing with different hole diameters correspondingly , wherein the portion of the insulating material is a lining, and the portion of the conductive material is a detection electrode or a ground electrode. Production method. 2. A heat removal hole is formed at the center of the molded body during the molding step.
2. The electromagnetic device according to claim 1, wherein the antenna is opened in advance.
Manufacturing method of flowmeter measurement tube. 3. The method for manufacturing an electromagnetic flowmeter measuring tube according to claim 1, wherein the two conductive materials are formed in a rod shape at a predetermined angle with each other so as to intersect with a center axis of the molded body. . 4. A plastics material such as polypropylene, polyphenylene sulphite, or polysulfone is used as the insulating material, and a conductive material such as carbon powder, carbon fiber or metal fiber is used as the conductive material. 2. The method according to claim 1, wherein conductive plastics mixed with a conductive material is used. 5. The cermet according to claim 1, wherein a ceramic such as alumina is used as the insulating material, and a cermet obtained by mixing platinum powder in the same material as the insulating material is used as the conductive material. Method for manufacturing an electromagnetic flowmeter measuring tube.