JP3474015B2 - Continuous measurement of oxygen activity in molten material - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for continuously measuring the oxygen activity in molten glass and other molten substances.

[0002]

2. Description of the Related Art For example, in the glass manufacturing process, it is known that the oxygen activity in the molten glass has a great influence on the color of the glass after it has been commercialized and on the amount of absorption of ultraviolet rays. Therefore, a device for continuously measuring the oxygen activity in the molten glass and reflecting it in the manufacturing process is expected, but a satisfactory device is not yet provided.

By the way, as an apparatus for measuring the oxygen activity in molten metal, for example, a shell made of zirconia solid electrolyte immersed in the molten metal and a predetermined oxygen activity provided on the inner surface of the shell are provided. There is known an apparatus provided with a standard electrode for giving a voltage, an external electrode immersed in a molten metal, and a potential difference measuring means for measuring a potential difference between the standard electrode and the external electrode. According to this device, when the shell body and the external electrode are immersed in the molten metal, the oxygen concentration battery is constituted by the standard electrode and the external electrode and the potential difference measuring means, and the solid electrolyte is provided between the standard electrode and the external electrode. The oxygen activity in the molten metal can be measured by the detected potential difference.

Therefore, if the above-mentioned oxygen activity measuring device in molten metal is applied to the oxygen activity measuring device in molten glass, it is possible to meet the above-mentioned expectations, but there are still many problems to be solved. There's a problem.

[0005]

In developing the above-mentioned application technique, the problems peculiar to the molten material to be measured must be taken into consideration. For example, when the shell is dipped in molten glass, the stabilized zirconia reacts with the molten glass and is eroded, which makes continuous measurement difficult.
In this respect, it is preferable to use stabilized zirconia such as MgO, CaO, or Y ₂ O ₃ as the zirconia solid electrolyte forming the shell, but there is a limit to the pot life in view of corrosion resistance and thermal shock resistance. , The desired continuous use cannot be satisfied (first problem).

[0006] Further, conventionally, as seen in an apparatus for measuring oxygen activity in molten metal, the external electrode is arranged apart from the solid electrolyte. When used for, since the molten glass between the external electrode and the solid electrolyte acts as an electrolyte, the size of the external electrode, the distance between the external electrode and the solid electrolyte, and the external electrode and the solid for the flow of the molten glass. The electromotive force changes due to the positional relationship of the electrolyte, and the reliability of measurement accuracy cannot be satisfied (second problem).

Further, in the conventional apparatus for measuring oxygen activity in molten metal, in order to form a standard electrode, a mixed powder of Mo--MoO _{2 is provided} inside the tip of a shell body made of a solid electrolyte.
Mixed powder of Cr-Cr ₂ O _3, or a technique of using a mixed powder or the like of the Ni-NiO is known, these mixed powder, the high temperature during device use while sintering to shrink, the solid electrolyte Since a gap is likely to occur between them, it is poor in long-term stability and is not suitable for continuous measurement (the third problem).

Further, in order to measure the oxygen activity using the solid electrolyte, it is necessary to measure the temperature of the molten substance to be measured together. Therefore, the oxygen activity measuring apparatus and the temperature measuring apparatus are conventionally used together. Although the installed structure is adopted, the side-by-side structure not only hinders downsizing as a whole, but also a pair of thermocouple wires for temperature measuring means and a pair of inner and outer electrodes for the potential difference measuring means. There is a problem that it is necessary to wire the lead wire, the wiring is complicated, and this hinders cost reduction of the entire device (fourth problem).

[0009]

The present invention provides an apparatus for continuously measuring the oxygen activity in a molten substance, which solves the above-mentioned problems.

Therefore, the present invention is configured as a means.
The roller consists of a solid electrolyte that is immersed in the melt to be measured.
And a predetermined oxygen activity provided on the inner surface of the shell
Standard electrode and external electrode immersed in the molten material to be measured
And measure the potential difference between the standard electrode and the external electrode
In molten material with potentiometric measuring means for
Alumina porcelain tube is connected to the protective tube in the activity measuring device.
Fix it and attach the oxygen activity measuring element unit to the tip of the alumina porcelain tube.
And the oxygen activity measuring element unit.
Is a cylindrical external electrode on the outer peripheral surface of the shell made of solid electrolyte.
To form a unit in which the
The pole is attached to the tip of the alumina porcelain tube.
Part electrode closely protects the outer peripheral surface of the shell body
And an opening that exposes the tip of the shell
In point . According to the present invention, it is provided at the tip of the alumina porcelain tube.
Gage oxygen activity measuring element unit is made of solid electrolyte
A cylindrical external electrode is closely fitted and fixed to the outer peripheral surface of the shell.
A cylinder in such a unit that constitutes a knit
The external electrode in the shape of a ring is attached to the tip of the alumina porcelain
There are features. Then, the outer electrode is formed into a cylindrical body and is fitted onto the outer periphery of the shell body, and the outer electrode thus formed closely protects the outer peripheral surface of the shell body, and the tip of the shell body. The feature is that an opening is formed to expose the part. According to this, the outer peripheral surface of the solid electrolyte is surrounded by the protective ring portion formed by the external electrode itself, and the outer peripheral portion of the solid electrolyte is preferably protected from erosion and thermal shock by the molten glass , and A continuous measuring device that can be used becomes possible, and the first problem can be solved. On the other hand, the tip of the solid electrolyte is exposed through the opening and contacts the molten glass to be measured, so that the potential difference can be satisfactorily measured by the potential difference measuring means as described above.

Further, according to the present invention, a cylindrical outer electrode is externally fitted to the outer circumference of a shell body made of a solid electrolyte, and the solid electrolyte and the outer electrode are closely arranged in a fixed state. Therefore, the electromotive force in the potential difference measuring means does not change. In particular, when the tip of the solid electrolyte is surrounded by the opening edge of the external electrode forming a tubular body, when the device is used for measuring the oxygen activity of the molten glass, the molten glass that acts as the electrolyte is the solid electrolyte. And the external electrode can be prevented from flowing as much as possible, a stable potential difference can be measured, and the second problem can be solved.

Further, according to the present invention, since the standard electrode is constituted by the air provided on the inner surface of the shell, it does not cause the contraction unlike the conventional mixed powder, and is suitable for stable continuous measurement for a long time. Therefore, the third problem can be solved.

Further, according to the present invention, by providing a thermocouple for temperature measurement on the inner surface of the distal end portion of the shell, there is provided an integrated device incorporating an oxygen activity measuring element unit and a temperature measuring element. Moreover, since one of the wires of the thermocouple is also used as the internal electrode lead wire for the potential difference measuring means, the wiring structure is simple and the cost of the entire device is reduced. Therefore, the fourth problem can be solved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

As shown in FIG. 1, the body fitting 1 has a metal protection tube 4 extending from a terminal box 3 provided with a lid 2 which can be opened and closed, and an air supply port 5 is provided on the protection tube 4. The terminal box 3 is provided with an air outlet 6 which also serves as a lead wire outlet. Although not shown in the drawing, an air supply means such as a blower or a compressor is connected to the main body fitting 1 to supply air to the air supply port 5 and discharge the air from the air discharge port 6. The supply and discharge of air may be performed in the reverse order to the above, and the portion indicated by reference numeral 6 may be the air supply port and the portion indicated by reference numeral 5 may be the air discharge port. Reference numeral 7 indicates a sliding flange provided on the protection tube 4.

As shown in FIGS. 1 and 2, the protective tube 4 is
Alumina porcelain tube 8 is connected and fixed via a refractory cement 9 to the end, and an oxygen activity measuring element unit 10 is provided at the tip of the alumina porcelain tube 8. This unit 1
Reference numeral 0 is composed of a shell body 11 made of a solid electrolyte, and a cylindrical outer electrode 12 which is closely fitted and fixed to the outer peripheral surface of the shell body 11. The shell 11 is formed in a bottomed cylindrical shape having a hemispherical closed end, and the external electrode 12 constitutes a cylindrical body concentric with the shell 11 and surrounds the outer peripheral surface of the shell 11. A protective ring portion 12a and an opening portion 12b for exposing the hemispherical tip portion 13 of the shell 11 are formed. In the illustrated embodiment, the opening edge of the opening 12b of the external electrode 12 and the tip of the tip 13 of the shell 11 are arranged substantially flush with each other.

Therefore, the cylindrical external electrode 12 is inserted into the tip of the alumina porcelain tube 8 and fixed by the refractory cement 14. As described above, the shell 11 is the external electrode 1
Since it is tightly fitted and fixed to 2, the oxygen resistance measuring element unit 10 as a whole is fixed to the alumina porcelain tube 8 by the refractory cement 14.

The solid electrolyte constituting the shell 11 can be selected from various zirconia solid electrolytes. When the apparatus is intended to measure oxygen activity in molten glass, MgO, CaO, Stabilized zirconia such as Y ₂ O ₃ is preferably used, and in consideration of corrosion resistance and thermal shock resistance against molten glass, MgO stabilized zirconia is preferably selected.

By the way, a standard electrode 15 for providing a predetermined oxygen activity is provided on the inner surface of the shell 11 made of a solid electrolyte. The standard electrode 15 can be made of, for example, a mixed powder of Fe, Ni, Cr, or Mo and their oxides, or can be made of air, CO gas, or the like. Considering the stability of time and the stabilization of oxygen activity, it is preferable to use air.

On the other hand, the external electrode 12 can be made of Mo, Fe or the like, but is made of Pt for the purpose of measuring the oxygen activity in the molten glass by this apparatus.

A thermocouple 16 for temperature measurement is installed in contact with the inner surface of the tip portion 13 of the shell body 11. In the illustrated example, the wire 16a on the negative electrode side is platinum, and the wire 16a on the negative electrode side is platinum. An R thermocouple in which the wire 16b is a platinum-rhodium alloy is used. These wires 16a and 16b are protected from heat by being inserted into the insulating tube 17 between the terminal box 3 and the shell 11, and the extended ends of both wires are connected to the terminal board of the terminal box 3. After that, as shown in FIG. 1, the temperature measuring means 18 is connected via a lead wire led out from the lead wire outlet 6 which also serves as an air outlet. The negative electrode side wire 16a made of platinum also serves as the internal electrode lead wire 19a as described later.

An external electrode lead wire 19b made of platinum is connected to the external electrode 12 made of platinum, and the connecting portion is preferably covered with the refractory cement 14 as shown in FIG. . The external electrode lead wire 19b is protected from heat by being inserted through a number of short insulating tubes 20 between the external electrode 12 and the terminal box 3, and the extended end of the lead wire 19b is connected to the terminal board of the terminal box 3. Then, as shown in FIG. 1, it is connected to the potential difference measuring means 21 via the lead wire led out from the lead wire outlet 6. That is, the potential difference measuring means 21 includes the external electrode lead wire 19b and the internal electrode lead wire 1 via the lead wire.
9a, and the internal electrode lead wire 19a is also used as the negative electrode side wire 16a of the thermocouple 16 as described above.

When measuring the oxygen activity in the molten substance to be measured, for example, molten glass, with the oxygen activity continuous measuring apparatus having the constitution of the above-mentioned embodiment, the oxygen activity in the suspended state by the sliding flange 7 is measured. The quantity measuring element unit 10 is immersed in molten glass.

The air supplied from the air supply port 5 of the metal protection tube 4 and discharged from the air discharge port 6 of the terminal box 3 is circulated into the shell body 11 via the alumina porcelain tube 8 and Thus, the standard electrode 15 that gives a stable oxygen activity is formed on the inner surface of the tip portion 13 of the shell 11. At the same time, the circulating air not only cools the shell 11 itself, but also cools the metal protection tube 4 and the alumina porcelain tube 8. At the same time, the insulating tube 17 in which the wires 16a and 16b of the thermocouple are inserted, In addition, the insulating tube 20 inserted through the external electrode lead wire 19b is cooled.

Therefore, the oxygen activity in the molten glass depends on the shell body 1.
Since it appears as a potential difference detected by the solid electrolyte constituting 1, the oxygen concentration battery is constituted by the standard electrode 15, the external electrode 12 and the potential difference measuring means 21, and the oxygen activity in the molten glass is determined by the potential difference measured there. To be measured.

The temperature of the molten glass is sensed by the thermocouple 16 through the tip 13 of the shell 11 and measured by the temperature measuring means 18.

In the above-mentioned embodiment, an apparatus mainly intended for continuous measurement of oxygen activity in molten glass was described, but within the scope of the claims, the shell 11 and the external electrode 12 are described.
Alternatively, it is of course possible to provide an apparatus for continuously measuring the oxygen activity in a molten substance to be measured such as molten metal by appropriately changing the design of the material configuration of the standard electrode 15, and in any case, the external electrode 12 The protection ring portion 12a can surround and protect the outer peripheral surface of the solid electrolyte, thus achieving the object of the present invention.

[0028]

Effects of the Invention According to the present invention described in claim 1, A
An oxygen activity measuring element unit provided at the tip of the Lumina porcelain tube 8.
A cylindrical outer surface of the shell 11 made of a solid electrolyte.
It constitutes a unit in which the partial electrodes 12 are closely fitted and fixed.
Therefore, the cylindrical external electrode 1 in such a unit is
2 is inserted into the alumina porcelain tube 8 and is melted.
An apparatus for continuously measuring oxygen activity in a molten material is provided. this
At this time , a cylindrical outer electrode 12 is externally fitted to the outer periphery of the shell body 11 made of a solid electrolyte, and the outer electrode 12 surrounds and protects the outer peripheral surface of the shell body 11.
2a and the opening 1 for exposing the tip 13 of the shell 11
2b is formed, the outer ring 12a formed by the external electrode 12 itself protects the outer peripheral surface of the solid electrolyte from erosion and thermal shock due to the molten substance to be measured, so that it can be used for a long time. A continuous measurement device that can withstand Since the tip portion 13 of the solid electrolyte is exposed through the opening 12b and contacts the molten substance to be measured, the potential difference measuring means 21 satisfactorily measures the desired potential difference, and oxygen in the molten substance to be measured is measured. The activity can be measured.

Moreover, by closely fitting the cylindrical outer electrode 12 onto the outer periphery of the shell body 11 made of solid electrolyte, the distance between the tip portion 13 of the solid electrolyte and the outer electrode 12 is fixed. Since they are arranged closely, the electromotive force in the potential difference measuring means 21 does not change,
Enables stable measurement. That is, the opening edge forming the opening 12b of the outer electrode 12 which is a cylindrical, since there as a configuration in which surrounds the distal end portion 13 of the solid electrolyte, a substance acting as an object to be measured molten material itself electrolyte as molten glass Even in some cases, the molten glass to be measured, which acts as such an electrolyte, has a solid electrolyte tip 13 and an external electrode 12.
It is possible to prevent the fluidization between and as much as possible, and to enable stable measurement of the potential difference.

[0030]

According to the invention as defined in claim 2, protection is provided.
An external electrode 12 is provided through the inside of the tube 4 and the alumina porcelain tube 8.
The external electrode lead wire 19b connected to the protective tube 4 and
Through the inside of the alumina porcelain tube 8, the inner surface of the tip of the shell 11
Both the thermocouple 16 for temperature measurement installed in the
And a temperature measuring means 18 connected to the strand.
Since the thermocouple 16 is installed on the inner surface of the tip portion 13 of the shell body 11, an overall compact device is provided as an integrated device in which the temperature measuring element 16 is incorporated in the oxygen activity measuring element unit 10. Not only is it possible, but since the one wire 16a of the thermocouple 16 is also used as the internal electrode lead wire 19a for the potential difference measuring means 21, the wiring structure is simple and the cost of the entire device is reduced. The effect is that you can do it.

[Brief description of drawings]

FIG. 1 is a front view showing a first embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional view of a main part of the embodiment.

[Explanation of symbols]

5 Air supply port 6 Air outlet for combined use of lead wire 10 Oxygen activity measuring element unit 11 Solid electrolyte shell 12 external electrodes 12a Protective ring part 12b opening 13 Tip of shell 15 standard poles 16 thermocouple 16a Negative pole side wire 16b Positive pole side wire 18 Temperature measuring means 19a Lead wire for internal electrode that also serves as thermocouple wire 19b External electrode lead wire 21 Potential difference measuring means

─────────────────────────────────────────────────── ─── Continuation of front page (72) Keiichi Mori 1-7-10 Nishihonmachi, Nishi-ku, Osaka City Kawaso Electric Machinery Co., Ltd. (72) Hisao Ikawa 1-7-10 Nishihonmachi, Nishi-ku, Osaka No. 56 in Kawaso Electric Machinery Co., Ltd. References JP-A-6-18473 (JP, A) JP-A-51-89495 (JP, A) JP-A-57-90151 (JP, A) 59-35862 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01N 27/411

Claims (2)

(57) [Claims] 1. A shell body made of a solid electrolyte immersed in a molten material to be measured, a standard electrode provided on the inner surface of the shell body to give a predetermined oxygen activity, and an external electrode immersed in the molten material to be measured. And an apparatus for measuring oxygen activity in a molten substance, comprising: an electric potential difference measuring means for measuring an electric potential difference between the standard electrode and the external electrode; and an alumina porcelain tube (8) for the protective tube (4). The oxygen activity measuring element unit (10) is connected and fixed, and the oxygen activity measuring element unit (10) is provided at the tip of the alumina porcelain tube (8). The oxygen activity measuring element unit (10) is a shell body (11) made of a solid electrolyte. ) A cylindrical external electrode (12) on the outer peripheral surface of
A cylindrical external electrode (12) is inserted and attached to the tip of an alumina porcelain tube (8), and the external electrode (12) is a shell body (11). A protective ring portion (12a) that closely surrounds the outer peripheral surface of (1) and an opening portion (12b) that exposes the tip portion (13) of the shell body (11) are formed. Oxygen activity continuous measuring device. 2. A protective tube (4) and an alumina porcelain tube (8)
The external electrode lead wire (19b) connected to the external electrode (12) through the inside of the shell, and the inside of the tip of the shell body (11) through the inside of the protective tube (4) and the alumina porcelain tube (8). A thermocouple (16) for temperature measurement and a temperature measuring means (18) connected to both strands of the thermocouple are provided, wherein the strands (16a, 16b) of the thermocouple (16) are The internal electrode lead wire (19a) is constituted by one of the wires, and the potential difference between the internal electrode lead wire (19a) and the external electrode lead wire (19b) is measured by the potential difference measuring means (21). 2. The apparatus for continuously measuring oxygen activity in a molten substance according to claim 1, wherein