JP2599322B2 - Manufacturing method of electrode for electromagnetic flow meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electrode in an electromagnetic flowmeter for measuring a flow rate of a conductive fluid flowing in a measuring tube.

[0002]

2. Description of the Related Art An electromagnetic flowmeter converts a flow rate of a conductive fluid flowing through a measuring tube into an electric signal by utilizing an electromagnetic induction phenomenon and measures the electric signal. fluororesin covering the inner wall surface and the flange outside surfaces of the measuring tube measuring tube of a conductive fluid in order to impart corrosion resistance with electrically insulated, and the lining material made of polyurethane or the like, so as to face the outer peripheral surface of the measuring tube a pair of saddle-type excitation coil which forms a magnetic field provided by a direction perpendicular to the flow direction of the fluid to be measured, opposite to arranged by the end that is perpendicular to the magnetic field in the tube wall central portion of the measuring tube 1 It is generally composed of a pair of electrodes that come into contact with the fluid to be measured, an earth ring disposed on the outer surface of the flange for grounding the measurement tube and the fluid to be measured and making them have the same potential, and a converter and the like. . The electrode is generally made of a noble metal such as platinum or titanium, and is fitted and fixed in an electrode mounting hole provided in the measurement tube.
Recently, there has been proposed a method in which a conductive material such as carbon fiber is mixed into a base material such as a fluororesin to produce an electrode, which is fitted into an electrode mounting hole and ultrasonically welded to a lining material.

[0003]

However, an electrode formed by mixing a conductive material such as carbon fiber into a base material such as a fluororesin is fitted into an electrode mounting hole and ultrasonically welded to a lining material. In the electrode mounting structure, if the mixing ratio of the conductive material is increased to increase the conductivity of the electrode, it is difficult to weld the electrode to the lining material, and the reliability of the liquid seal between the lining material and the electrode decreases, There was a problem that the liquid easily leaked.

Accordingly, the present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to improve the sealing performance between the electrodes and the lining material by integrally molding them. It is an object of the present invention to provide a method of manufacturing an electrode for an electromagnetic flowmeter, which is capable of reliably preventing liquid leakage.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and has a measurement tube having an electrode mounting hole.
A cavity is formed by inserting a core into the inside of the
Fix the nut member corresponding to the electrode mounting hole,
Into which an electrode formed by mixing a powdery conductive material into
A pole positioning jig is screwed into the nut member and the electrode
Inserting into the mounting hole and pressing the inner end face against the surface of the core
In both cases, the push rod inserted into the electrode positioning jig
Therefore, the inner end face of the electrode is pressed against the surface of the core,
Inject lining material heated and melted into the cavity
Before the lining material solidifies,
Tool from the electrode mounting hole and remove the lining material.
By inserting it into the gap between the electrode mounting hole and the electrode,
The lining material and the electrode are formed integrally .

[0006]

In the present invention, the lining material is used for positioning the electrode.
The jig is pulled out of the electrode mounting hole,
It enters the gap between the pole mounting hole and the electrode. Electrodes and linings
The material is welded and integrally formed so that these two members
Seal the space between them.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings. FIG. 1 is a cross-sectional view for explaining a method of manufacturing an electrode for an electromagnetic flow meter according to the present invention, and FIG. 2 is a lining.
FIG. 3 is a sectional view showing a state immediately after the material is injected, and FIG.
It is a figure showing signs that a jig for decision is extracted. These figures
In the above, 1 is a measuring tube formed in a cylindrical body open at both ends,
Flanges 2 and 3 are provided integrally at the outer peripheral portions of both ends, and a pair of electrode mounting holes 4 are provided at the central portion of the outer peripheral surface.
5 is coaxially formed so as to face in a direction orthogonal to the axis of the measuring tube 1. 6 is a mold which has the measuring pipe 1 is loaded, the shaft in the mold 6 is measuring pipe 1
It has a core 7 inserted in line with a line, and an injection port 8,
A cavity 11 is formed between the inner wall surface 9 of the measuring tube 1 and the outer flange surface 10. Reference numeral 12 denotes a lining material made of fluorine resin or the like that covers the inner wall surface 9 and the flange outer surface 10 of the measuring tube 1.
The lining material heated and melted into the cavity 11 from the injection port 8 is subjected to high pressure (injection pressure of about 100 kgf / c).
m ² ).

Reference numeral 30 denotes an electrode positioning jig (hereinafter referred to as a jig)
The jig 30 is formed in a cylindrical body open at both ends.
The electrode 14 is held by the
Attached via 32. For this reason, the outer periphery of the jig 30
On the surface base side, a male screw screwed into the female screw of the nut member 32
Are formed. Such a jig 30 is a nut member
32, the distal end surface is tightly attached to the peripheral surface of the core 7.
Touched. The nut member 32 is formed in a cylindrical body with both ends open.
The axis of the outer peripheral surface of the measuring tube 1 is aligned with the electrode mounting holes 4 and 5.
They are fixed by welding or the like. The electrode 14 is
Platinum and titanium are contained in a base material made of the same material as the lining material 12.
Powder of tongue, monel, hastelloy, carbon particles, carbon fiber, etc.
Is formed by mixing a conductive material in a shape, and is inserted into the jig 30.
Is done. The electrode 14 is connected to the jig 30 by the measuring tube 1.
Is attached to the push rod 31 inserted into the jig 30.
Therefore, it is pressed and pressed against the peripheral surface of the core 7.

In the manufacture of the electrode, the electrode 14 is inserted and inserted.
The jig 30 is screwed into the nut member 32 and the tip is
It is inserted into the pole mounting hole 4 and the front end surface is brought into contact with the core 7. Ma
In addition, the electrode 14 is pressed against the core 7 by the push rod 31.
You. The lining material 12 that has been heated and melted in this state is
Filled into the cavity 11 at high pressure, and the lining material 12
Pull out only the jig 30 from the electrode mounting hole 4 before the
You. As a result, a shape is formed between the electrode mounting holes 4 and 5 and the electrode 14.
Lining material 12 still in a molten state in the space to be formed
Penetrates due to the pressure applied to the lining material
Thus, it is possible to integrally form with the electrode 14. At this time,
The surface of the pole 14 is melted by the heat of the molten lining material 12.
To be welded to the lining material 12.

In the method of manufacturing such an electrode 14,
Is the formation of the lining material 12 itself and the measurement tube for the electrode 14
1 has the advantage that it can be mounted simultaneously
At the same time, the lining material 12 and the electrode 14 are integrally formed.
Therefore, the seal portion can be substantially eliminated. I
Therefore, the liquid seal between them is very good and
Reliable and surely prevent liquid leakage from the electrode mounting holes 4 and 5.
Can be

FIGS . 4A to 4E show the shapes of the electrodes.
It is. To improve the reliability of welding and liquid tightness
Increase the contact area between the lining material 12 and the electrode 14
It is preferable that the inner end of the electrode 14 is
To the inner surface of the measuring tube 1
It must be able to withstand minutes. So, the electrode
One peripheral groove 21 may be formed on the peripheral surface of (14)
(See FIG.), Three circumferential grooves 21 are formed (FIG.
22 (FIG. 3 (c)) or a thread groove 23 was formed.
(Fig. (D)) or the inner end as shown in (e)
Or a tapered portion 24 that expands toward the liquid contact side
In this case, the line is compared with the straight electrode 14 shown in FIG.
The contact area contact and bond strength between the training material 12 and the electrode 14
Both can be increased. Therefore, welding and
And liquid-tight reliability and pressure resistance can be further improved.
Things.

[0012]

As described above, the method for manufacturing an electrode for an electromagnetic flowmeter according to the present invention is directed to a method for manufacturing a measuring tube having an electrode mounting hole.
A core is inserted inside to form a cavity, and the outer peripheral surface is
Fix the nut member corresponding to the electrode mounting hole and insert
An electrode into which an electrode formed by mixing a powdery conductive material is inserted
Screw the positioning jig onto the nut member and remove the electrode
Inserting into the hole and pressing the inner end face against the surface of the core
In particular, a push rod inserted into the electrode positioning jig is used.
Press the inner end face of the electrode against the surface of the core,
Inject lining material melted by heating into cavity
Before the lining material solidifies,
Tool from the electrode mounting hole and remove the lining material.
By inserting it into the gap between the electrode mounting hole and the electrode,
The lining material and the electrode are formed integrally
Thus, the bonding between the lining material and the electrode is extremely good, and the sealing portion can be substantially eliminated. As a result, the sealing performance is high, the liquid can be reliably prevented from leaking from the electrode mounting holes, and the electrodes are integrally formed at the time of forming the lining material. The effect is great.

[Brief description of the drawings]

FIG. 1 illustrates a method of manufacturing an electrode for an electromagnetic flow meter according to the present invention.
Description is a cross-sectional view for.

FIG. 2 is a sectional view showing a state immediately after a lining material is injected .
FIG.

FIG. 3 is a diagram showing a state in which an electrode positioning jig is extracted.
It is.

4A to 4E are diagrams showing various shapes of electrodes.
It is.

[Explanation of symbols] 1 ... measuring tube, 2, 3 ... flange, 4, 5
... Electrode mounting hole, 6 ... mold, 7 ... core, 8 ... injection port, 11 ... cavity, 12 ... lining material, 14 ... electrode, 30 ... electrode positioning jig, 31 ... push rod, 32 ...
Nut member.

Claims (1)

(57) [Claims] A core is provided inside a measuring tube having an electrode mounting hole.
To form a cavity and attach the electrode to the outer peripheral surface.
Fix the nut member corresponding to the hole, and place the powdered conductive material in the base material.
For positioning the electrode into which the electrode formed by mixing the material is inserted
Screw the jig into the nut member and insert it into the electrode mounting hole
While pressing the inner end face against the surface of the core,
The above-mentioned electrode is pushed by a push rod inserted into the electrode positioning jig.
Press the inner end face of the pole against the surface of the core,
Inject the heated and molten lining material into the
Before the solidification material solidifies, the electrode positioning jig is
Pull out the lining material from the mounting hole and
The lining is inserted into the gap with the electrode.
A method for manufacturing an electrode for an electromagnetic flowmeter, comprising integrally forming a material and an electrode .