JPH0875553A - Temperature measuring apparatus for high temperature liquid employing optical fiber - Google Patents

Abstract

PURPOSE: To measure the temperature of high temperature liquid continuously. CONSTITUTION: The temperature measuring apparatus for high temperature liquid comprises a temperature measuring nozzle 20 penetrating a vessel 40 for receiving high temperature liquid and touching the high temperature liquid at the forward end thereof, means 10 for feeding the forward end of an optical fiber coated with metal tube from a winding drum 16 through the rear end side of the nozzle 20 into the high temperature liquid in the vessel 40, means 30 for feeding an anti-clogging gas to the nozzle 20, and a radiation thermometer 17 connected with the rear end of the optical fiber 11 and measuring the temperature of the high temperature liquid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the temperature of a high temperature liquid, for example, the temperature of molten metal in a furnace using an optical fiber, and more particularly to a temperature measuring apparatus capable of continuous temperature measurement.

[0002]

2. Description of the Related Art As a method for measuring the temperature of a molten metal in a furnace, a sublance method or a manual thermocouple measuring method has been conventionally used, for example, in a converter.

In the sublance method, temperature measurement is performed from a raw material charging port of a furnace (container) or the like by a temperature measuring element attached to the tip of the lance of a lance-shaped movable body.

Therefore, the sublance system has the following disadvantages. (1) The temperature measuring device grows in size in proportion to the size of the furnace (container). (2) Since the temperature sensing element is a disposable item that can be used only once, it is necessary to replace the temperature sensing element each time the temperature is measured, and the replacement device is additionally required. (3) Since it is necessary to replace the consumable thermocouple each time the temperature is measured, the melting temperature during operation must be measured intermittently, and the temperature sensor is frequently used for economical reasons. I can't measure temperature. Therefore, the actual temperature at the processing end point and the target temperature do not always match with each other, which may cause energy loss, increase in production cost, and hindering productivity.

In the sublance system, since it is difficult to continuously measure the temperature as described above, various methods for continuously measuring the temperature inside the furnace have been studied.

A conventional technique for continuously measuring the temperature in the furnace is disclosed in, for example, Japanese Patent Laid-Open No. 61-91529.

In this temperature measuring method, the temperature inside the furnace is measured by using an optical fiber. However, since the optical fiber tip is fixed to the tip of the temperature measuring nozzle, the gas layer blown from the tip of the temperature measuring nozzle. Therefore, there is a big problem in measurement accuracy. Further, the tip of the optical fiber is exposed to a high temperature for a long time, which causes a problem of measurement accuracy due to aging.

There is also one disclosed in Japanese Patent Laid-Open No. 63-203716. In this temperature measurement method, the molten steel temperature is continuously measured so that the temperatures at the end of blowing and at the end point become the target values, and the amount of the component at the end point is estimated from the rate of change of the heating rate. In the control method, "a method can be used in which the optical fiber is immersed in molten steel from the bottom, side wall, or upper portion of a reaction vessel such as a converter, and the molten steel temperature is continuously measured by a radiation thermometer connected to the optical fiber." However, there is no specific description, and the technical content is unknown.

The applicant of the present invention, in Japanese Unexamined Patent Publication No. 5-248960, inserts the tip of a metal tube-coated optical fiber into molten steel as a temperature-measuring element, and measures that the blackbody radiation condition is satisfied at the tip of the optical fiber. Using the principle, a device for measuring temperature by connecting a radiation thermometer to the other end of the optical fiber, and an optical fiber conveying means for sending out and rewinding the metal tube-coated optical fiber are provided, and only the time for measuring the temperature of the molten steel, Insert the tip of the metal tube coated optical fiber into the molten steel for a short time, pull up the tip immediately after the measurement is completed, cut the tip used as this temperature measuring element, and measure with the new tip at the next measurement The temperature measuring device for

[0010]

However, the temperature measuring device according to the above-mentioned Japanese Patent Laid-Open No. 5-248960 is an intermittent temperature measuring device, and the tip of the optical fiber used as a temperature measuring element at a constant time or at every temperature measurement. Needed to be cut off. Therefore, this device has a problem that continuous measurement cannot be performed for a long period of time.

The present invention has been made in order to solve such problems, and it is possible to continuously measure the temperature of a high temperature liquid, for example, the temperature of molten metal in a furnace using an optical fiber for a long period of time, and the response is high. The aim is to obtain an optical fiber temperature measuring device that is fast and has high measurement accuracy.

[0012]

A temperature measuring device for a high temperature liquid by means of an optical fiber according to the present invention is a temperature measuring device arranged so that a tip thereof comes into contact with the high temperature liquid through a wall of a container holding the high temperature liquid. A nozzle, an optical fiber supply means for inserting the tip of the optical fiber coated with a metal tube from the rear end side of the temperature measuring nozzle to continuously or intermittently feed the high temperature liquid in the container, and a nozzle for the temperature measuring nozzle. It is composed of a gas supply means for supplying an anti-clogging gas, and a radiation thermometer connected to the rear end of the metal tube coated optical fiber for measuring the temperature of the high temperature liquid, wherein the temperature measuring nozzle has the metal at the center of the cross section. The refractory has a through hole through which the tube-covered optical fiber passes, and the side wall portion is made of a refractory material having a plurality of metal wires for strength reinforcement arranged in the nozzle longitudinal direction.

Further, a temperature-measuring nozzle which is arranged so as to penetrate the wall of the container holding the high-temperature liquid so that its tip comes into contact with the high-temperature liquid, and the tip of the metal tube-covered optical fiber is arranged at the rear end side of the temperature-measuring nozzle. Optical fiber supply means for continuously or intermittently feeding the high temperature liquid in the container through the above, gas supply means for supplying a nozzle clogging prevention gas to the temperature measuring nozzle, and the metal tube coated optical fiber And a radiation thermometer connected to an end to measure the temperature of the high-temperature liquid. It is composed of an inner pipe in which a plurality of short pipes are connected in the longitudinal direction, and a metal outer pipe containing the inner pipe.

Further, a temperature-measuring nozzle which is disposed so as to penetrate the wall of the container for holding the high-temperature liquid so that its tip comes into contact with the high-temperature liquid, and the tip of the metal tube-covered optical fiber is connected to the rear end side of the temperature-measuring nozzle. Optical fiber supply means for continuously or intermittently feeding the high temperature liquid in the container through the above, gas supply means for supplying a nozzle clogging prevention gas to the temperature measuring nozzle, and the metal tube coated optical fiber The temperature measuring nozzle is composed of a radiation thermometer which is connected to an end and measures the temperature of the high temperature liquid. It is configured by connecting a plurality of short tubes having a fitting structure in the longitudinal direction.

[0015]

In the present invention, the tip of the metal tube-coated optical fiber is continuously or intermittently fed into the high-temperature liquid by inserting the temperature measuring nozzle into the high-temperature liquid by the optical fiber supplying means, and the metal tube-coated optical fiber after the winding is inserted. A radiation thermometer connected to the end measures the temperature of the hot liquid in the container.

During temperature measurement, the tip of the temperature measuring nozzle comes into contact with the high temperature liquid in the container, and the high temperature liquid enters the gap between the inner wall of the temperature measuring nozzle and the optical fiber from the tip to block the temperature measuring nozzle. Therefore, the nozzle clogging prevention gas is supplied from the rear end side of the temperature measuring nozzle, which is outside the container, to the gap to prevent the tip of the temperature measuring nozzle from being blocked by the high temperature solution.

By the way, when the temperature measuring nozzle has a structure in which a metal pipe such as a stainless pipe is embedded in a container of refractory holding a high temperature liquid, for example, in the case of refining steel such that refining temperature exceeds 1600 ° C. In this case, a metal tube such as a stainless tube will be melted.

When the metal tube is melted, the metal tube-coated optical fiber and the melted metal tube are welded to each other, and the optical fiber cannot be continuously supplied.

When the nozzle clogging prevention gas is increased in an attempt to prevent the melting of the metal tube, a mushroom (a sponge-like lump in which the molten metal is partially solidified) is formed at the tip of the temperature measuring nozzle, and this mushroom measures the temperature. Since the hot nozzle is blocked, the metal tube-coated optical fiber cannot be supplied in this case as well.

Therefore, in the present invention, the temperature measuring nozzle is made of a refractory material (MgO-C brick or the like in the case of refining steel) having a through hole for supplying the metal tube coated optical fiber at the center of the cross section. .

Further, in the case where the refractory lining for containing the molten metal is made of refractory, the refractory has a thickness of 1000 mm or more. The refractory ruptures from this hole as a starting point due to stress, the nozzle clogging prevention gas leaks, the molten metal enters from the tip of the temperature measuring nozzle, the temperature measuring nozzle is clogged, and the optical fiber is caught at the broken part. , The stable supply of optical fiber cannot be achieved.

Therefore, in the present invention, a plurality of metal wires for reinforcing the strength are built in the outer wall forming the through holes of the refractory nozzle along the longitudinal direction of the nozzle, and the temperature is measured by thermal stress or the like. Prevents the nozzle from being damaged.

Therefore, in the present invention, due to the inability to supply the optical fiber due to the melting damage of the metal tube, which occurs when the metal tube is used for the temperature measuring nozzle, or the thermal stress when simply making a hole in the refractory, etc. The situation that the optical fiber cannot be supplied due to the breakage can be avoided, and the optical fiber can be directly supplied into the molten metal to stably measure the temperature continuously for a long time.

For the above-mentioned reason, a plurality of ceramic short tubes having a length of 150 mm or less having a through hole for passing the metal tube-covered optical fiber in the central portion of the cross section are connected in the longitudinal direction of the temperature measuring nozzle. You may comprise from an inner pipe and the metal outer pipe which contains this inner pipe.

In this case, the metal tube-covered fiber does not directly fuse with the metal tube forming the temperature measuring nozzle, so that it is not fused. In addition, since the inner pipe is made by connecting multiple short pipes with a length of 150 mm or less, unlike the long single pipe, thermal stress and thermal shock are dispersed and it is difficult to break, so the nozzle clogging prevention gas will not leak. Absent.

Here, the length of the ceramic tube is 150 mm.
The reason for setting the length below is that there is a risk of breaking due to thermal stress or the like if the length is longer than this.

Also in the case of this temperature measuring nozzle, the optical fiber can be directly supplied into the molten metal to stably measure the temperature continuously for a long time.

For the same reason, a plurality of ceramic short tubes having a fitting structure with a length of 100 mm or less having a through hole for passing the metal tube-covered optical fiber in the center of the cross section of the temperature measuring nozzle. The structure may be connected in the longitudinal direction.

In this way, the metal tube-coated fiber will not be welded to the ceramics constituting the temperature measuring nozzle. Further, since the length of the ceramic tube is 100 mm or less and the fitting structure is adopted, thermal stress and thermal shock are relieved at the connection portion, and the ventilation resistance to the surroundings is large, and the nozzle clogging prevention gas does not leak.

Here, the length of the ceramic tube is 100 mm.
The reason for setting the length below is that the effect of relaxing the thermal stress is reduced if the length is longer than this.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing the construction of a temperature measuring device for a high temperature liquid using an optical fiber according to the present invention. In the figure, 10 is an optical fiber supply device, which comprises a metal tube coated optical fiber 11, a motor 12, a roller 13, a feed controller 14, a feed speed detector 15, an optical fiber drum 16 and a radiation thermometer 17. Reference numeral 20 denotes a temperature measuring nozzle for inserting the metal tube coated optical fiber 11 into the furnace, which is also called a temperature measuring tuyere. Reference numeral 21 denotes an optical fiber guide that is connected to the temperature measuring nozzle 20. The optical fiber guide 21 allows the metal tube-covered optical fiber 11 to pass therethrough and supplies the nozzle clogging prevention gas. A nozzle clogging prevention gas supply device 30 includes a pressure / flow rate controller 31, a supply gas controller 33, a supply gas generation unit 34, and a gas pressure detector 35. Reference numeral 40 is a furnace such as a converter or an electric furnace.

The optical fiber temperature measuring device according to the present invention measures the temperature of the high temperature liquid, for example, the temperature of the molten metal in the furnace. It is directly inserted into the molten metal or slag in the furnace together with the gas N ₂ ) and the tip portion of the metal tube coated optical fiber 11 is melted and lost due to the high temperature. Therefore, a new optical fiber is constantly sent out by the melted amount and the supply is continued. This enables continuous temperature measurement.

Here, the structure in which the optical fiber is covered with a metal tube is because the pressure of the nozzle clogging prevention gas is applied to the optical fiber when the optical fiber is fed into the furnace by the optical fiber supply device 10. This is to secure the strength and protect the optical fiber inside.

A stainless steel tube, for example, is used as the metal tube for coating the optical fiber. Since the melting point of this stainless steel is about 1400 to 1430 ° C., it does not melt immediately even when it is inserted into high temperature molten steel, and protects the optical fiber for several seconds. In this embodiment, the optical fiber is also 160
Since it is made of quartz glass having a softening point of 0 ° C. or higher, it can maintain its shape without melting for a short time.

The metal tube coated optical fiber 11 in this embodiment has an outer diameter of 1.2 mm.

The temperature measuring nozzle 20 includes, for example, one made of brick or ceramics, one made of a single metal tube, or one made of a single metal tube having a ceramic inside, and the like. Between the outer diameter of the inner temperature measuring nozzle and the inner diameter of the outer metal tube, a metal tube is concentrically provided on the outside of the temperature measuring nozzle constituted by the metal single tube or the metal single tube whose inside is ceramics. There is also a double-tube structure in which the void provided in is connected to the nozzle clogging prevention gas supply device 30.

One end of the temperature measuring nozzle 20 is in contact with a high temperature liquid, and the other end is airtightly coupled to the optical fiber guide 21, and the metal tube coated optical fiber 11 is inserted from the optical fiber guide 21 side and inserted into the high temperature liquid. .

A gap is provided between the inner diameter of the temperature measuring nozzle 20 and the outer diameter of the metal tube coated optical fiber 11.
Nozzle clogging prevention gas is blown into this gap through the optical fiber guide 21.

2A and 2B are explanatory views showing a first embodiment of a temperature measuring nozzle 20 of a temperature measuring device for a high temperature liquid by an optical fiber according to the present invention. FIG. 2A is a perspective view of the temperature measuring nozzle, and FIG. It is a longitudinal cross-sectional view of a temperature measuring nozzle. The temperature measuring nozzle 20 is formed by forming a through hole 51 having an inner diameter of 3 mm at the center of a cross section of a MgO-C (magcarbon) refractory 50 having an outer diameter of 200 mm and a length of 1000 mm. Is a stainless steel wire 52 with an outer diameter of 1.5 mm for strength reinforcement.
Are embedded along the longitudinal direction of the plurality of temperature measuring nozzles 20.

FIG. 3 is an explanatory view showing a second embodiment of the temperature measuring nozzle 20 of the temperature measuring device for a high temperature liquid by the optical fiber of the present invention. FIG. 3A is a vertical sectional view of the temperature measuring nozzle.
(B) is explanatory drawing which shows the connection method of an alumina tube. The temperature measuring nozzle 20 is arranged so as to penetrate through a furnace wall refractory material 41 that constitutes a furnace, and an inner tube 61 in which a plurality of alumina short tubes 62 having an inner diameter of 2 mm and a length of 75 mm for inserting the optical fiber 11 are connected. , Inner diameter of this inner tube 61 is 4m
m outer tube 65 of a metal tube (SUS304).

The connection between the inner pipe 61 and the outer pipe 65 will be described. The outer pipe 65 is also formed by connecting a plurality of stainless short pipes 66 having a length of 75 mm, and a stepped portion is formed on the inner wall of one end of the stainless short pipe 66. The stepped portion and the collar portion provided on the outer peripheral surface of the alumina short tube 62 at one end are fitted to each other to form a composite tube, and the composite tube is connected by welding.

In addition to alumina, the ceramic tube may be zirconia, boron nitride, or Si-Al-O.
-N-based ceramics may be used.

FIG. 4 is a vertical sectional view showing a third embodiment of the temperature measuring nozzle 20 of the temperature measuring device for a high temperature liquid using the optical fiber of the present invention. The temperature measuring nozzle 20 is disposed so as to penetrate the furnace wall refractory material 41 that constitutes the furnace, and has an inner diameter of 3 mm (outer diameter 7 to 10 m) for inserting the optical fiber 11.
m), an alumina tube 71 in which a plurality of alumina short tubes 72 having a length of 52 mm are connected. A fitting portion is formed on the front end portion 72a and the rear end portion 72b of the alumina short tube 72 so that the adjacent alumina short tubes 72 can be fitted together without a gap.

The optical fiber guide 21 measures the metal tube coated optical fiber 11 continuously fed from the optical fiber supply device 10 together with the nozzle clogging prevention gas supplied from the nozzle clogging prevention gas supply device 30 and the temperature measuring nozzle 20.
It has a function of sending out to the molten metal in the furnace 40 through.

One end of the optical fiber guide 21 is hermetically connected to one end of the temperature measuring nozzle 20 which is not in contact with the high temperature liquid, and the other end thereof can pass the metal tube coated optical fiber 11, but the nozzle clogging prevention gas is used as the optical fiber supply device. 1
In order to prevent leakage to the 0 side, a highly airtight structure is provided with, for example, a double seal. In addition, a pipe from the nozzle clogging prevention gas supply device 30 is coupled to the space provided between the inner diameter of the optical fiber guide 21 and the outer diameter of the metal tube-coated optical fiber 11 to supply the gas.

As described above, the optical fiber guide 21 is composed of a member different from the temperature measuring nozzle 20, but the function of sending the optical fiber into the furnace 40 together with the nozzle clogging prevention gas is exactly the same, and in a broad sense, the temperature measuring is performed. It can be regarded as a member forming a part of the nozzle 20.

From the temperature measuring nozzle 20 which is airtightly connected to the optical fiber guide 21, the metal tube coated optical fiber 11 is fed.
The nozzle clogging prevention gas is blown into the molten metal in the furnace 40 at the same time.

In this case, since bubbles are generated in the floating region of the nozzle clogging prevention gas in the molten metal, if the tip of the metal tube-covered optical fiber 11 enters the bubble generation region, the temperature measurement accuracy will deteriorate. Therefore, for example, the temperature measuring nozzle 20 is installed with an inclination angle (for example, about 30 degrees) downward from the horizontal plane, and the metal tube coated optical fiber 11 is installed.
It is desirable not to let the tip of the tip enter into the floating region of the gas.

The optical fiber supply device 10 has a function of feeding the metal tube-coated optical fiber 11 into the furnace 40 continuously or intermittently via the optical fiber guide 21 and the temperature measuring nozzle 20.

For this reason, the feed controller 14 drives the motor 12 to feed out the metal-tube-coated optical fiber 11 which is previously wound in the optical fiber drum 16. In this case, the feed speed detector 15 feeds the optical fiber. The speed is detected, and the detected value is used to control the feed speed to a predetermined value.

In this embodiment, the continuous feeding speed of the optical fiber is 5 mm / sec, and the intermittent feeding speed is 10 mm / sec for 10 seconds and then 20 seconds.
The operation of stopping for a second is repeated.

In the delivery of this optical fiber, the tip of the metal tube-coated optical fiber 11 which is inserted into the furnace 40 together with the nozzle clogging prevention gas is melted away with the passage of time. (Only the amount consumed)
Conducted to constantly supply new optical fiber. And continuous supply of this new optical fiber enables continuous temperature measurement.

The feed rate detector 15 can obtain the feed rate from the rotation angle of the sensor roller within a unit time, for example, and this detection signal is used as a feed gas controller in the feed controller 14 and the nozzle clogging prevention gas supply device 30. 33.

Then, depending on whether or not the detection value of the feed rate detector 15 is within the normal range, it is possible to determine the difficulty state of the optical fiber delivery. For example, if the tip of the temperature measuring nozzle 20 becomes clogged, the feed rate will decrease.
The feed controller 14 stops the drive of the motor 12 when the feed speed falls below the normal range to prevent the device from malfunctioning.

In the present invention, the measurement principle that the absolute temperature can be calculated from the radiation spectrum distribution if the blackbody radiation condition is satisfied is utilized. Therefore, the spectrum light emitted from the molten metal is input from the tip of the metal tube-coated optical fiber 11 inserted in the furnace 40, and this spectrum light propagates in the optical fiber and is input to the radiation thermometer 17.

The radiation thermometer 17 includes, for example, a two-color thermometer for determining the temperature by comparing the luminance outputs of two wavelengths and an infrared radiation thermometer for directly determining the temperature from the luminance output of the radiated light. The temperature is calculated from the signal according to each measuring method, and the calculated temperature signal is output as an electric signal and supplied to, for example, a recording meter (not shown) or the like.

Gases supplied by the nozzle clogging prevention gas supply device 30 to the optical fiber guide 21 include an inert gas (nitrogen gas in this example), an oxidizing gas (oxygen gas in this example), an inert gas and an oxidizing gas. Any one of the three kinds of gases (mixing ratio of which can be variably set) is selected and used. Also, the selection of this gas type is
The operation is performed manually or automatically depending on the difficulty of sending out the metal tube coated optical fiber 11 by the optical fiber supply device 10. The embodiment of FIG. 1 shows a case where this gas type is automatically selected.

The supply gas controller 33 in the nozzle clogging prevention gas supply device 30 detects the detection signal of the gas pressure detector 35 and the feed speed detector 1 in the optical fiber supply device 10.
5 detection signals are input, one of the three types of nozzle clogging prevention gas is automatically selected according to the values of these two detection signals, and the control signals based on the selection results are respectively pressure / flow rate. Supply to the regulator 31.

The pressure / flow rate regulator 31 includes a pressure regulator,
A flow rate adjuster, a control valve, and the like are included, and the input nitrogen gas and oxygen gas are supplied to the supply gas generation unit 34 as pressure and flow rate according to the control signal. In the supply gas generation unit 34, either nitrogen gas, oxygen gas or a mixed gas of both is generated at a predetermined pressure and is supplied to the optical fiber guide 21 from here.

The gas pressure detector 35 includes the supply gas generator 3
4 detects the gas pressure supplied to the optical fiber guide 21, and supplies this detected value to the supply gas controller 33. This is because when the tip of the temperature measuring nozzle 20 is clogged, the amount of gas supplied is reduced and the detected value of gas pressure rises. Therefore, it is necessary to measure whether the detected value is within the normal range or not. This is because the clogging state of the tip of the warm nozzle 20 can be determined.

The supply gas controller 33 judges the clogging state of the tip of the temperature measuring nozzle 20 based on the detection value of the supply gas pressure and the detection value of the optical fiber feeding speed, and automatically selects the gas type.

In the embodiment of FIG. 1, the supply gas controller 33 determines that the temperature measuring nozzle 20 is in the case where the optical fiber feed speed detection value and the supply gas pressure detection value are within the normal range.
And the metal tube coated optical fiber 11 inserted in the furnace 40
In order to protect the nozzles, an inert gas (nitrogen gas in FIG. 1) having a cooling effect is selected as the nozzle clogging prevention gas.

However, when the flow rate of the inert gas is too large, mushrooms (spongy mass in which the molten metal is partially solidified) are formed at the tip of the temperature measuring nozzle 20.
Is generated and the insertion of the metal tube-covered optical fiber 11 becomes impossible.

On the other hand, if the flow rate of the inert gas is too low, the molten metal is inserted into the tip of the temperature measuring nozzle 20.

In the example of FIG. 1, the pressure / flow rate cooker 3
The amount of nitrogen gas blown into the optical fiber guide 21 adjusted by 1 is 5.0 Nm3 / Hr (1389 cc / s)
ec), the linear flow velocity of the gas at the tip of the temperature measuring nozzle 20 is adjusted to an optimum value within the range of 50 to 500 Nm / sec. Further, in order to secure this linear flow velocity, it is most preferable that the ratio of the inner diameter of the temperature measuring nozzle 20 to the outer diameter of the metal tube coated optical fiber 11 is in the range of approximately 1.5 to 3.5.

Even if the temperature is measured by blowing nitrogen gas as described above, the feed rate of the optical fiber is decreased and the supply gas pressure is increased due to the formation of mushrooms at the tip of the temperature measuring nozzle 20 in the furnace 40. Sometimes.

In this case, the supply gas controller 33
As the nozzle clogging prevention gas, a mixed gas in which oxygen gas is mixed with nitrogen gas at a predetermined ratio is selected. Although the mixing ratio of the mixed gas can be variably set, normally, from the viewpoint of protection of the temperature measuring nozzle 20, it is preferable that the mixing ratio of the oxygen gas is limited to 50% at the maximum.

The supply gas controller 33 controls the pressure / flow rate regulator 31 based on the selection result to generate a mixed gas having the predetermined mixing ratio, and blows the mixed gas into the optical fiber guide 21 to dissolve mushrooms or the like. Therefore, the adhesion can be prevented.

However, when the mixed gas is blown out, the feed rate of the optical fiber and the supply gas pressure may not return to the normal range due to strong mushroom adhesion or the like. In this case, therefore, the supply gas controller 33 prevents the nozzle clogging. As the gas, select oxygen gas for a short time,
This oxygen gas is used for dissolution.

FIG. 5 is a diagram showing an example of a temperature measurement result using an optical fiber under the following measurement conditions in a converter. (1) Temperature measuring nozzle, model: Composite single tube nozzle Inner diameter / outer diameter: 4.0 mm / 8.0 mm Material: SUS304 + Si3 N4 (2) Optical fiber, structure: Stainless steel tube outer diameter: 1.2 mm (3) Gas injection, type: Nitrogen gas injection rate: 5.0 Nm3 / Hr Injection flow rate: 121 Nm / sec (4) Optical fiber feed rate: 5 mm / sec (continuous) or 10 mm / sec (intermittent) In Fig. 5, it fluctuates up and down. The waveform measured is the temperature measured by the optical fiber, and the sublance measurement for confirming the accuracy is performed intermittently. The temperature measured by the thermocouple at this time is indicated by a black circle.

The difference between the peak value measured by the optical fiber and the value measured by the thermocouple was 4 ° C. on average. The error of 4 ° C. with respect to the measurement temperature of 1600 ° C. was a measurement accuracy of 0.25%, which was a fairly good accuracy.

The feeding speed of the optical fiber is 5 m continuously.
Approximately the same measurement results were obtained in the case of m / sec and the case of intermittent delivery of 10 mm / sec for 10 seconds and then stopping for 20 seconds.

As a nozzle clogging gas, a mixed gas of nitrogen gas and oxygen gas was blown in if necessary, so that the trouble of stopping the optical fiber insertion did not occur.

FIG. 6 is a diagram showing a comparison between the thermocouple indicated value (Ts) and the optical fiber thermometer indicated value (Tf). Ts is shown on the horizontal axis and Tf is shown on the vertical axis. It is indicated by a mark. The □ mark in FIG. 4 is approximately Ts = Tf.
Is distributed on a straight line, indicating that the measurement result is good.

FIG. 7 shows a case in which the temperature of a high temperature liquid is continuously measured by the temperature measuring device of the present invention, which uses a temperature measuring nozzle in which the nozzle body is made of refractory and is reinforced with stainless wire (Example 1). The continuous temperature measurement time until nozzle clogging is the same when using a refractory (MgO-C brick) that is not reinforced with stainless wire for the temperature measurement nozzle, and when using a stainless pipe (SUS, inner diameter 3 mm, outer diameter 5 mm). It is the graph shown in comparison. As is clear from this graph, it is understood that the continuous temperature measurement time can be lengthened by the temperature measurement device of the present invention as compared with the conventional one.

In FIG. 8, a temperature measuring nozzle of the present invention is one in which a ceramic short tube is connected to the inner tube, and a metal tube is used as the outer tube. Compare the continuous temperature measurement time until nozzle clogging when continuously measuring the temperature, compared with the case where an alumina single tube was used for the temperature measurement nozzle and the case where a stainless single tube (inner diameter 3 mm, outer diameter 5 mm) was used. It is the graph shown. Also in this case, as is apparent from this graph, it is understood that the continuous temperature measurement time can be lengthened by the temperature measurement device of the present invention as compared with the conventional one.

FIG. 9 shows that a high temperature liquid is continuously measured by the temperature measuring device of the present invention in which a plurality of short tubes having a ceramic fitting structure are connected (Example 3) is used as a temperature measuring nozzle. 7 is a graph showing the continuous temperature measurement time until clogging of the nozzle when compared with the case where an alumina single tube was used for the temperature measurement nozzle and the case where a stainless single tube (inner diameter 3 mm, outer diameter 5 mm) was used. . Also in this case, as is apparent from this graph, it is understood that the continuous temperature measurement time can be lengthened by the temperature measurement device of the present invention as compared with the conventional one.

[0078]

According to the present invention, when measuring the temperature of a high temperature liquid, the tip of the optical fiber coated with metal tube is directly inserted into the high temperature liquid through the temperature measuring nozzle together with the nozzle clogging prevention gas, and the tip of the optical fiber is inserted. Since a new optical fiber is constantly sent out and supplied as much as the part is melted by high temperature, long-term continuous measurement is possible.
In addition, it is possible to obtain a temperature measuring device using an optical fiber, which has fast response and good measurement accuracy.

Further, according to the present invention, the temperature measuring nozzle is made of a refractory with a built-in metal wire for strength reinforcement, and is a composite pipe consisting of an inner pipe connected with ceramic short pipes and a metal outer pipe,
Furthermore, since a plurality of short tubes having a ceramic fitting structure are connected, it is possible to avoid an accident in which the optical fiber coating tube and the temperature measuring nozzle are fused and the feeding of the optical fiber is stopped, The durability of the temperature measuring nozzle has been improved and it has become possible to use it for a long time.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a temperature measuring device using an optical fiber according to the present invention.

FIG. 2 is an explanatory diagram showing a first embodiment of a temperature measuring nozzle of a temperature measuring device for a high temperature liquid using an optical fiber according to the present invention,
(A) is a perspective view of a temperature measuring nozzle, (b) is a longitudinal cross-sectional view of the temperature measuring nozzle.

FIG. 3 is an explanatory view showing a second embodiment of the temperature measuring nozzle of the temperature measuring device for a high temperature liquid by the optical fiber of the present invention,
(A) is a longitudinal sectional view of the temperature measuring nozzle, and (b) is an explanatory view showing a method of connecting the alumina tube.

FIG. 4 is a vertical cross-sectional view showing a third embodiment of the temperature measuring nozzle of the temperature measuring device for a high temperature liquid using the optical fiber of the present invention.

FIG. 5 is a diagram showing an example of a temperature measurement result using the optical fiber according to the present invention.

FIG. 6 is a diagram showing a comparison between a thermocouple command value and an optical fiber thermometer command value.

FIG. 7 is a graph showing continuous temperature measurement time when a refractory temperature measuring nozzle with a built-in metal wire for strength reinforcement is used in the temperature measuring device for high temperature liquid by the optical fiber of the present invention.

FIG. 8 shows a continuous temperature measurement time when a temperature measurement device for a high temperature liquid using an optical fiber of the present invention uses a temperature measurement nozzle of a composite pipe consisting of an inner pipe connected to a ceramic short pipe and a metal outer pipe. It is a graph.

FIG. 9 is a graph showing a continuous temperature measurement time when a temperature measurement nozzle in which a plurality of short tubes having a fitting structure made of ceramics are connected to the temperature measurement device for a high temperature liquid by the optical fiber of the present invention.

[Explanation of symbols]

 10 Optical Fiber Feeding Device 11 Metal Tube Covered Optical Fiber 12 Motor 13 Roller 14 Feeding Controller 15 Feeding Speed Detector 16 Optical Fiber Drum 17 Radiation Thermometer 20 Temperature Measuring Nozzle 21 Optical Fiber Guide 30 Nozzle Clogging Prevention Gas Supply 31 Pressure / Flow Regulator 33 Supply Gas controller 34 Supply gas generator 35 Gas pressure detector 40 Furnace 41 Refractory 50 Refractory 51 Through hole 52 Stainless wire 61 Inner tube 62 Alumina short tube 65 Outer tube 65 66 Stainless short tube 71 Alumina tube 72 Alumina short tube

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsuyoshi Murai 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Steel Pipe Co., Ltd. (72) Ichiro Kikuchi 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Date Inside the Steel Pipe Co., Ltd. (72) Inventor Hideaki Mizukami 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Steel Pipe Inside Co., Ltd. (72) Toru Mukai 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nippon Steel Pipe Co., Ltd. (72) Inventor Yukio Ishiguchi 1-2, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Kyosuke Shirasaki 1-2, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan KK Stock In-house (72) Inventor Kimi Komatsu 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Tube Co., Ltd.

Claims (3)

[Claims] 1. A temperature-measuring nozzle which is disposed so as to penetrate a wall of a container holding a high-temperature liquid so that its tip comes into contact with the high-temperature liquid, and a tip of a metal tube-coated optical fiber is connected to a rear end side of the temperature-measuring nozzle. An optical fiber supply means for continuously or intermittently feeding the high temperature liquid in the container through
The temperature measuring nozzle comprises a gas supply means for supplying a nozzle clogging preventing gas to the temperature measuring nozzle, and a radiation thermometer connected to the rear end of the metal tube coated optical fiber for measuring the temperature of the high temperature liquid. Has a through hole through which the metal tube-coated optical fiber passes in the central portion of the cross section, and the side wall portion is made of a refractory material containing a plurality of metal wires for strength reinforcement arranged in the nozzle longitudinal direction. Temperature measuring device for high temperature liquids using optical fiber. 2. A temperature-measuring nozzle which is arranged so as to penetrate the wall of a container holding a high-temperature liquid so that its tip comes into contact with the high-temperature liquid; An optical fiber supply means for continuously or intermittently feeding the high temperature liquid in the container through
The temperature measuring nozzle comprises a gas supply means for supplying a nozzle clogging preventing gas to the temperature measuring nozzle, and a radiation thermometer connected to the rear end of the metal tube coated optical fiber for measuring the temperature of the high temperature liquid. Is an inner tube in which a plurality of ceramic short tubes having a length of 150 mm or less having a through hole for passing the metal tube-coated optical fiber in the center of the cross section are connected in the longitudinal direction, and a metal tube containing the inner tube. An apparatus for measuring the temperature of a high-temperature liquid using an optical fiber, which is composed of an outer tube. 3. A temperature-measuring nozzle which is arranged so as to penetrate a wall of a container holding a high-temperature liquid so that its tip comes into contact with the high-temperature liquid, and a tip of a metal tube-covered optical fiber is connected to a rear end side of the temperature-measuring nozzle. An optical fiber supply means for continuously or intermittently feeding the high temperature liquid in the container through
The temperature measuring nozzle comprises a gas supply means for supplying a nozzle clogging preventing gas to the temperature measuring nozzle, and a radiation thermometer connected to the rear end of the metal tube coated optical fiber for measuring the temperature of the high temperature liquid. Is characterized in that a plurality of short tubes made of ceramics having a fitting structure with a length of 100 mm or less having a through hole for passing the metal tube-covered optical fiber at the center of the cross section are connected in the longitudinal direction. Temperature measuring device for high temperature liquids using optical fiber.