JPH09126894A - Optical temperature measuring method for high temperature liquid and its optical temperature measuring device - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To measure the temperature of a high temperature liquid continuously and accurately.
In the method of measuring the temperature of a high temperature liquid by converting an optical signal transmitted through the optical fiber into a temperature amount, the tip of the optical fiber is intermittently dipped in the high temperature liquid, and the measurement peaks at the time of immersion and pulling are measured. Temperature is measured with the sandwiched steady value, and the tip of the optical fiber that has been devitrified by immersion in a high-temperature liquid is cut during pulling up, and the new optical fiber tip is immersed in a high-temperature liquid to measure the next temperature. A method and an apparatus for measuring an optical temperature of a high temperature liquid, characterized in that

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical temperature measuring method and a measuring apparatus therefor capable of easily and accurately measuring the temperature of a high temperature molten material such as a copper making furnace.

[0002]

2. Description of the Related Art Thermocouples have been conventionally used to measure the temperature of molten metal, and there are consumable thermocouples that are directly charged into molten metal and those stored in a ceramic protective tube. Are known. However, in the consumable thermocouple, the sensor probe must be replaced for each measurement, and the measurement operation is complicated. In addition, the cost is inevitable because it is disposable. On the other hand, the one having a protective tube has a problem in corrosion resistance and thermal shock resistance of its material, and the measuring time can be maintained only for about 5 to 20 hours.

In addition to such a thermometer using a thermocouple, a temperature measuring method using an optical fiber is also practiced.
For example, a method is known in which the tip of a ceramic protective tube that houses the detection end of an optical fiber is immersed in molten metal, and the radiant heat of the immersed portion is transmitted as an optical signal to a radiation thermometer through the optical fiber to measure the temperature. (JP-A-4-348236
No., JP-A-4-329323, etc.). However, this method has a problem that the immersion accuracy at the tip of the optical fiber is contaminated and the measurement accuracy is lowered. In addition, as a countermeasure against this, a gas for preventing dirt from adhering to the tip portion is also made to flow (Japanese Patent Laid-Open No. Sho 61-135).
No. 60-231126), but in this case, the temperature of the tip part is lowered by the gas flow, and there is a limit to improving the measurement accuracy.

Further, a method of immersing the tip of an optical fiber in a high temperature liquid and measuring the temperature by directly detecting the radiated light of the liquid is also practiced (Japanese Patent Laid-Open No. 62-19729). In the case of a high temperature liquid such as an iron-making furnace, where the temperature of the liquid reaches 1500 ° C or higher, the tip of the quartz fiber melts during the immersion of the liquid, so the new fiber end face is always in contact with the liquid. It can be measured, but the copper melt is 120
When the temperature is around 0 ° C., there is a problem that the temperature cannot be continuously measured like the iron melt due to the temperature of the melt, and the measurement error is large.

An object of the present invention is to provide a temperature measuring method and a device therefor, which solves the above-mentioned problems in the conventional immersion consumable temperature measuring method using an optical fiber.

[0006]

The inventor of the present invention is unable to continuously measure the temperature of a conventional copper melt because the temperature of the copper melt is considerably lower than the melting point of quartz, and quartz is substantially less than molten copper. This is because the tip of the quartz fiber inserted in the melt does not melt like the iron melt and rather causes devitrification because it is not soluble in the melt.To solve this, the fiber is pulled up intermittently. Even if you repeatedly cut the devitrified tip and insert it into the copper melt again, sparks will be generated when inserting and pulling the fiber, and even if the measured radiant light is simply converted into the temperature amount, it will be accurate. It has been found that it is impossible to detect various melt temperatures and the measurement error increases.

Based on the above findings, the present invention intermittently inserts and removes a fiber into and from a melt, cuts a devitrified fiber tip, and removes a measurement peak generated at the time of fiber insertion and pulling up. It enables accurate and continuous temperature measurement by measuring the temperature with a steady value sandwiched between.

That is, according to the present invention, the following optical temperature measuring methods described in claims 1 and 2 are provided. (1) In a method of measuring the temperature of a high temperature liquid by immersing the optical fiber end in a high temperature liquid and converting an optical signal transmitted through the optical fiber into a temperature amount, the optical fiber end is intermittently changed to the high temperature liquid. Immerse, measure the temperature with a steady value sandwiched between the measurement peaks during immersion and pulling up, and further cut the devitrified optical fiber tip due to immersion in high temperature liquid during pulling up, The method for measuring an optical temperature of a high temperature liquid, comprising immersing the new tip of the above into a high temperature liquid and performing the next temperature measurement. (2) The optical temperature measuring method according to (1) above, wherein the high temperature liquid is copper, copper oxide or copper sulfide, or a liquid containing these.

Further, according to the present invention, the following optical temperature measuring devices described in claims 3 to 5 are provided. (3) An optical fiber whose tip is immersed in a high-temperature liquid to transmit the radiant light of the high-temperature liquid, a feeding / injecting means for intermittently taking the optical fiber in and out of the high-temperature liquid, and guiding the optical fiber toward the high-temperature liquid An optical temperature measuring device comprising: a guide means for cutting, a means for cutting an end of an optical fiber pulled up from a high temperature liquid, and an optical temperature detector for converting an optical signal transmitted by the optical fiber into a temperature amount. (4) The optical temperature measuring device as described in (3) above, wherein the sending and receiving means also serves as the winding means for the optical fiber. (5) The cutting means is a shearing machine, the shearing machine is provided at the feed-in position of the tip of the optical fiber, and the tip of the optical fiber is arranged between the blades of the shearing machine so that it can be freely taken in and out.
The optical temperature measuring device described in (3) or (4).

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to illustrated embodiments. FIG. 1 is a conceptual diagram showing an outline of a measuring method and a measuring apparatus of the present invention, FIG. 2 is a schematic sectional view of a fiber tip and a guide member, and FIG. 3 is a chart showing a measurement result according to the present invention.

(I) Measuring Device In the measuring device of the present invention shown in the figure, the tip of the high temperature molten metal 10
And an optical fiber 20 which transmits the radiant light of the high temperature liquid. As shown in FIG. 2, the optical fiber 20 is a quartz fiber 20 composed of a core glass and a clad.
A is a core wire, which is reinforced by a metal coating 20b made of an extremely thin stainless tube, and a resin coating 20c is provided on the outer periphery of the metal coating 20b. The optical fiber 20 may be one that is commonly used for optical communication.

The optical fiber 20 is wound around a bobbin 21 by a predetermined amount, while the optical fiber 20 is melted above the molten metal of the furnace 30 in which the high temperature molten material 10 is stored.
A guide means 40 for leading to the 0 level is provided. The guide means 40 may be a pipe or a trough-shaped member through which the optical fiber 20 penetrates. The guide means 40
A shearing machine 50 for cutting the tip of the optical fiber is disposed near the outlet (feeding-in position) of the optical fiber, and the tip of the optical fiber is reciprocally inserted between the blades of the shearing machine 50.

A pinch roll 22 is provided between the bobbin 21 and the guide means 40 for moving the optical fiber 20 into and out of the high temperature liquid 10. It should be noted that instead of the pinch roll 22, other delivery / injection means may be used, and the rotation driving means may be connected to the winding shaft of the bobbin 21, and the optical fiber 20 may be taken in and out by driving the winding shaft. good. An optical temperature detector 60 that converts the optical signal transmitted by the optical fiber into a temperature amount is connected to the rear end of the optical fiber 20. A temperature indicator is attached to the detector 60 if necessary. The detector 60 can use a commercial item.

(II) Measuring Method To measure the temperature of the high temperature liquid 10 such as a copper melt, the optical fiber 20 is pulled out by rotating the winding shaft of the pinch roll 22 or the bobbin 21, and the tip of the optical fiber 20 is heated. 10
And radiate the radiated heat generated from the melt into the optical fiber 2
0 to the optical temperature detector 60. The transmitted optical signal is converted into a temperature amount by the detector 60.

In this case, since the tip of the fiber immersed in the copper melt or the like gradually devitrifies due to the high temperature, the tip of the fiber is pulled up after being immersed for a predetermined time, and the devitrified tip is cut by the shearing machine 50. . After cutting, the fiber tip is inserted again into the melt 10 and the measurement is repeated. In addition, in the case of devitrification after dipping a predetermined number of times, the tip portion may be cut as necessary after dipping a predetermined number of times.

As described above, when the tip of the optical fiber is intermittently taken in and out of the high-temperature melt, the resin coating 20c of the metal coating 20b and the resin coating (UV coating) on the outer circumference of the quartz fiber core wire are burned during immersion to form a frame. As shown in FIG. 3, a remarkable temperature peak a is recorded at the start of measurement in the temperature measurement chart. This frame can be reduced by using a metal coating from which the resin coating has been removed, but since the resin coating on the outer periphery of the quartz fiber core wire cannot be removed, the occurrence of a frame during immersion is inevitable. Furthermore, even when the tip of the optical fiber is pulled out of the melt, the oxygen concentration in the open air is higher than the oxygen concentration in the melt, so violent combustion occurs at the moment the tip of the optical fiber touches the open air, and the temperature measurement chart shows A pronounced temperature peak b similar to the beginning is recorded.

The temperature peak due to the frame when the optical fiber is dipped and pulled up does not have a great influence because the melt temperature is high in the iron melt, but in the copper melt the melt temperature is lower than the temperature peak. The disturbance causes a large measurement error. Therefore, in the measuring method of the present invention, the measurement peaks a and b during immersion and pulling up are excluded, and the steady value c sandwiched between the measurement peaks a and b is used as the measurement temperature.

In the above temperature measurement, since a molten material having a uniform temperature is directly observed through a sufficiently small end face of the fiber tip, a situation based on so-called cavity radiation is realized, and an approximate ideal black body is obtained. Since it can be regarded as radiation, it is not necessary to correct the emissivity according to the type and properties of the melt, and accurate measurement results can be obtained. In addition, the responsiveness is fast, and sufficient temperature measurement can be performed with an immersion time of about 2 to 3 seconds.

As described above, in the above measuring method and measuring apparatus of the present invention, the tip of the optical fiber is intermittently taken in and out of the high temperature liquid, the devitrified tip is removed at the time of pulling up, and the measurement is repeated again. Since the temperature is measured by removing the disturbance during fiber immersion and pulling, continuous measurement with high accuracy is possible even for liquids whose melting temperature is considerably lower than the melting temperature of quartz, such as copper melting. Is. Specifically, it is suitable for measuring the temperature of copper, copper oxide or copper sulfide in a copper-making furnace, or a mixture containing these, and further, a temperature equal to or near these, for example, a temperature of about 1000 to 1400 ° C. Suitable for temperature measurement of high temperature liquids with temperature.

[0020]

[Examples] Using the measurement system shown in FIG. 1, the temperature of a copper melt and a slag melt in a crude copper gutter of a continuous copper-making furnace were measured. In addition, the optical fiber is a quartz core wire (quartz part φ 125 μm
, Resin coating 125 μm) with metal coating (φ1.2 mm) excluding resin coating was used. The tip of this optical fiber was dipped in a molten copper material for about 5 seconds and then pulled up, and the tip of the fiber was cut to about 5 cm and then inserted again into the molten material.

FIG. 3 shows the measurement results for each measurement (twice). Further, the temperature value at each measurement time is shown in FIG. 4 in comparison with the measurement result of the consumable thermocouple. In the figure, ◯ indicates the measured value according to the present invention, and ● indicates the measured value by the consumable thermocouple. As shown in the figure, the temperature measurement result of the present invention is in good agreement with the temperature measurement result of the consumable thermocouple, and it can be seen that the reliability is high. Moreover, unlike consumable thermocouples, it can be used repeatedly and is excellent in operability and economy.

[0022]

According to the temperature measuring method and the measuring apparatus of the present invention described above, it is possible to continuously and accurately measure a liquid such as a copper liquid whose melting temperature is considerably lower than the melting temperature of quartz. It is possible to measure various melt temperatures. Further, the measuring system of the present invention has good operability and is excellent in economic efficiency.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a temperature measuring system according to the present invention.

FIG. 2 is a schematic sectional view of the tip of an optical fiber used in the temperature measuring system.

FIG. 3 is a temperature measurement chart by the above measurement system.

FIG. 4 is a graph showing the comparison between the values measured by the above measurement system and the values measured by a consumable thermocouple.

[Explanation of symbols]

10-high temperature liquid, 20-optical fiber, 21-bobbin, 22-pinch roll, 30-furnace, 40-guide means, 50-shearer 60-light temperature detector

Claims (5)

[Claims] 1. An optical fiber tip is immersed in a high temperature liquid,
In the method of measuring the temperature of a high temperature liquid by converting an optical signal transmitted through the optical fiber into a temperature amount, the tip of the optical fiber is intermittently dipped in the high temperature liquid, and the measurement peaks at the time of immersion and pulling are measured. The temperature is measured with the sandwiched steady value, and the tip of the optical fiber that has been devitrified by immersion in the high temperature liquid is cut when pulling up if necessary, and the new tip of the optical fiber is immersed in the high temperature liquid. A method for measuring an optical temperature of a high temperature liquid, which comprises performing the following temperature measurement. 2. The optical temperature measuring method according to claim 1, wherein the high-temperature liquid is copper, copper oxide or copper sulfide, or a liquid containing these. 3. An optical fiber whose tip is immersed in a high-temperature liquid to transmit radiant light of the high-temperature liquid, a delivery means for intermittently inserting and removing the optical fiber from the high-temperature liquid, and an optical fiber directed to the high-temperature liquid. 1. An optical temperature measuring device comprising: a guide means for guiding the optical fiber, a means for cutting an end of an optical fiber pulled up from a high temperature liquid, and an optical temperature detector for converting an optical signal transmitted by the optical fiber into a temperature amount. 4. The optical temperature measuring device according to claim 3, wherein the sending and receiving means also serves as a winding means for the optical fiber. 5. The cutting means is a shearing machine, the shearing machine is provided at a feed-in position of the tip of the optical fiber, and the tip of the optical fiber is arranged between the blades of the shearing machine so as to be freely taken in and out. The optical temperature measuring device described in 4.