JPS6112543B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention reduces the amount of oxygen in the molten metal by using the electromotive force of an oxygen concentration battery caused by the difference in the concentration of oxygen ions between the standard electrode and the molten metal. The present invention relates to a method and apparatus for continuously measuring quantities.

The amount of oxygen in molten metal can be measured using an oxygen concentration cell, but the structure commonly used as a device for this purpose is as shown in Figure 1, where the lower end is closed and a platinum wire, etc. The oxygen ion solid electrolyte tube 3 connected to the lead wire 4 is fixed inside the external electrode tube 1 using a fixing agent 2 such as cement, and oxygen or an oxygen-containing gas such as air is introduced into the solid electrolyte tube 3. The solid electrolyte tube 3 is introduced into the molten metal 5 to form a standard electrode, and the tip of the solid electrolyte tube 3 is inserted into and brought into contact with the molten metal 5.
The electromotive force obtained by the difference in oxygen ion concentration occurring on both sides of the solid electrolyte tube 3 is taken out by the external electrode tube 1 and the internal lead wire 4 and measured.

However, in this device, if the fixing agent comes into contact with the molten metal for a long time, the fixing agent will react with the molten metal and affect the electromotive force. Therefore, as shown in FIG.
The fixing agent 2 and the molten metal 5 are made such that air or other gas 6 remains between the fixing agent 2 and the molten metal 5 between the external electrode tube 1 and the solid electrolyte tube 3 when inserted into the tube. In this case, the tip of the solid electrolyte tube 3 protrudes beyond the surface of the fixative 2, so that even if the fixative reacts with the molten metal, there is no effect. It has become almost non-existent.

However, in the device shown in FIG. 2, the device is vertically inserted into the molten metal from above, so the residual gas 6 is absorbed into a large area surrounded by the external electrode tube 1, the solid electrolyte tube 3, the fixing agent 2, and the molten metal 5. The solid electrolyte tube 3 cannot make sufficient contact with the molten metal 5, and as a result, no signal can be obtained for some time (1 to 2 hours) after the device is inserted into the molten metal. Another disadvantage was that a stable and sufficient electromotive force could not be obtained during measurement.

The present invention has been made to eliminate these drawbacks, and by restricting the residual gas space to the space adjacent to the fixing agent, contact between the solid electrolyte tube and the molten metal is guaranteed immediately after insertion. This makes stable measurements possible.

The present invention will be explained below with reference to embodiments shown in FIGS. 3 and 4.

The configuration of the device is basically the same as that in Fig. 2, but as shown in Fig. 3, a cylindrical solid electrolyte tube 3 serving as an oxygen ion conductor is placed at the center of the cylindrical external electrode tube 1. The solid electrolyte tube 3 is fixed inside the electrode tube 1 with an annular fixing agent 2 surrounding the solid electrolyte tube 3. This fixing agent 2 is the external electrode tube 1
and are arranged above the lower end surface of the solid electrolyte tube 3, and when the measuring device enters the molten metal 5, the inner surface of the external electrode tube 1, the outer surface of the solid electrolyte tube 3, the lower surface of the fixative 2, and the molten metal 5 are Air or gas 6 is left in the area surrounded by the surface to prevent reaction between the fixing agent and the molten metal.

At that time, in order to leave the necessary amount of residual air or gas in the part that comes into contact with the fixing agent, the slit 7 is cut a necessary length from the lower end surface of the external electrode tube 1 as shown in Figure 4 A and B.
It is cut in.

Alternatively, as shown in FIG. 4C, a through hole 8 may be formed at a position at a required height from the lower end surface of the external electrode cylinder 1.

This slit 7 or through hole 8 allows the molten metal to easily enter the upper end of the slit or the through hole, and the tip of the solid electrolyte tube comes into sufficient contact with the molten metal. .

As a result, stable measurements can be made immediately after the measuring device is inserted into the molten metal, and a stable electromotive force can be obtained for a long period of time since the reaction between the fixative and the molten metal is prevented due to residual gas.

It is preferable that the tip of the solid electrolyte tube 3 is aligned with the lower end surface of the external electrode tube 1 or positioned slightly inward.

This is because the solid electrolyte tube 3 is susceptible to shock, so if its tip is exposed from the external electrode tube 1, care must be taken when assembling them, and also during measurement, slag and impurities in the molten metal will be transferred to the solid electrolyte. There is a possibility of direct contact with the tip of the tube. Therefore, since it is necessary to protect the tip of the solid electrolyte tube from this, it is desirable to avoid making the tip of the solid electrolyte tube protrude further than the end surface of the external electrode tube.

To give a specific example of the measuring device, a SUS310 pipe with an outer diameter of 27.2 mmφ and a thickness of 3 mm is used as the external electrode tube, and an outer diameter of 8 mmφ and an inner diameter of 5 mm is used as the solid electrolyte tube.
Zirconia of φ was used. In addition, fireproof cement was used as the fixing agent, the distance from the bottom surface of the fixing agent to the tip of the solid electrolyte tube was 10 mm, and there were 4 through holes.
A mmφ hole was drilled at a position 5 mm from the bottom end of the external electrode tube. As a result, when continuously measuring the amount of oxygen in molten metal, gas can remain in the space 10 mm below the fixative up to 3 mm, and 7 mm below that.
could be filled with molten metal.

Thus, according to the present invention, the solid electrolyte tube and the molten metal come into sufficient contact immediately after the measuring device is inserted into the molten metal, making it possible to measure the amount of oxygen at the same time as the insertion, and the residual gas prevents the fixative from melting. It prevents reactions with metals, and since the tip of the solid electrolyte tube protrudes beyond the fixative, there is little effect even if the fixative reacts with the molten metal, allowing for stable measurements over long periods of time. It becomes possible.

On the other hand, in the conventional device shown in FIG. 2, after being inserted into molten metal, the solid electrolyte tube and molten metal do not come into sufficient contact due to the influence of residual gas, making it impossible to obtain a signal immediately. Therefore, by tilting the device to reduce the amount of residual gas, or by waiting for the gas to enter the molten metal little by little over time, the signal will not be output until about an hour after insertion. It is recognized that the effects of the present invention are significant.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the principle of a device for continuously measuring the amount of oxygen in molten metal, Fig. 2 is a sectional view of a conventional measuring device in which gas remains, and Fig. 3 is a sectional view of an embodiment of the present invention. A sectional view of the measuring device shown in Fig. 4A,
B and C are a side view and a plan view of an example in which a slit is provided in the external electrode cylinder, and a side view of an example in which a through hole is provided. DESCRIPTION OF SYMBOLS 1... External electrode tube, 2... Fixing agent, 3... Solid electrolyte tube, 4... Lead wire, 5... Molten metal, 6
...Residual gas, 7...Slit, 8...Through hole.

Claims (1)

[Claims] 1. A solid electrolyte tube made of an oxygen ion conductor with its lower end closed and connected to a lead wire is fixed inside the tip of an external electrode tube using a fixing agent, and oxygen or oxygen is injected into the solid electrolyte tube. The closed end of the solid electrolyte tube is inserted into the molten metal by introducing a gas containing it, and the oxygen in the molten metal is removed by utilizing the electromotive force of the oxygen concentration battery caused by the difference in the concentration of oxygen ions. In the method of measuring the amount, a fixing agent interposed between the solid electrolyte tube and the external electrode tube to fix them, and a fixing agent interposed between the solid electrolyte tube and the molten metal into which the tip of the solid electrolyte tube is inserted. The gas to prevent the reaction between the fixing agent and the molten metal is restricted to the space adjacent to the fixing agent provided inward from the tip surface of the solid electrolyte tube and the external electrode cylinder, and the gas remains in the space immediately after the solid electrolyte tube is inserted. A method for continuously measuring oxygen in molten metal, characterized in that oxygen in molten metal is brought into sufficient contact with the molten metal. 2. A solid electrolyte tube made of an oxygen ion conductor with its lower end closed and connected to a lead wire is fixed inside the tip of the external electrode tube using a fixing agent, and oxygen or an oxygen-containing gas is introduced into the solid electrolyte tube. In an apparatus for measuring the amount of oxygen in molten metal by inserting the closed end of the solid electrolyte tube into molten metal and utilizing the electromotive force of an oxygen concentration battery generated by the difference in concentration of oxygen ions. , the fixing agent interposed between the solid electrolyte tube and the external electrode tube to fix them, and the molten metal into which the tip of the solid electrolyte tube is inserted, when measuring oxygen in the molten metal. In order to prevent the reaction between the fixative and the molten metal, a slit is provided to a position that limits the residual gas to the space adjacent to the fixative provided inward from the tip surface of the solid electrolyte tube and the external electrode cylinder, or 1. An apparatus for continuously measuring oxygen in molten metal, characterized in that a through hole is provided in the external electrode tube at a position such that the tip of the solid electrolyte tube maintains contact with the molten metal immediately after insertion.