JP3166483B2 - Optical fiber temperature measuring device - 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 measuring the temperature of a high-temperature liquid using an optical fiber, for example, the temperature of a molten metal in a furnace, and more particularly to a temperature measuring apparatus capable of continuously measuring the temperature.

[0002]

2. Description of the Related Art Conventionally, as a method for measuring the temperature of molten metal in a furnace, a sublance method or a manual thermocouple measuring method has been implemented in a converter for decarburizing molten iron, which is a steel refining furnace, for example. Have been. In the sub-lance method, temperature measurement is performed from a raw material input port of a furnace (vessel) or the like by a temperature measuring element attached to a lance tip of a lance-shaped movable body.

Therefore, the sublance system has the following disadvantages. First, the temperature measuring device becomes huge in proportion to the size of the furnace (vessel). Further, since the temperature measuring element is disposable for one-time use, it is necessary to replace the temperature measuring element for each temperature measurement, and a replacement device is additionally required. In addition, since the consumable thermocouple needs to be replaced every time the temperature is measured, the measurement of the melting temperature during the operation process must be intermittent. Temperature cannot be measured. Therefore, the actual temperature at the processing end point does not always coincide with the target temperature, which may cause energy loss, increase in production cost, and impairment of productivity.

[0004] Next, as a well-known document of a method for continuously measuring the temperature in a furnace, there is one disclosed in, for example, JP-A-61-91529. The temperature measurement method according to this document measures the temperature inside the furnace using an optical fiber, but since the optical fiber tip is fixed to the nozzle tip,
Since the temperature is measured through the gas layer blown from the nozzle tip, there is a great problem in the measurement accuracy. Further, the tip of the optical fiber is exposed to a high temperature for a long time, and there is a problem due to a change with time.

In Japanese Patent Application Laid-Open No. 63-203716, the temperature of molten steel is continuously measured so that the temperature during blowing and at the end point becomes a target value, and the temperature at the end point is determined from the rate of change of the heating rate. In the method of controlling the refining of molten steel, which estimates the amount of components, `` The optical fiber is immersed in the molten steel from the bottom, side wall, or top of the 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 has filed a Japanese Patent Application No.
No. 8736 (JP-A-5-24896),
The tip of the optical fiber coated with a metal tube is inserted into molten steel as a temperature measuring element, and a radiation thermometer is connected to the other end of the optical fiber using the measurement principle that the blackbody radiation condition is satisfied at the tip of the optical fiber. A device that performs
In addition, an optical fiber conveying means for sending and rewinding the metal tube-coated optical fiber is provided, and the tip of the metal tube-coated optical fiber is inserted into the high-temperature liquid for a short time only when the temperature of the molten steel is measured. We proposed a temperature measuring device that cuts off the tip used as the temperature measuring element and uses the new tip for the next measurement.

[0007]

However, the temperature measuring device disclosed in Japanese Patent Application No. 4-78736 (Japanese Patent Application Laid-Open No. Hei 5-24896) is an intermittent temperature measuring device, and is used for a certain period of time or every temperature measurement. It was necessary to cut the tip of the optical fiber used as the temperature measuring element. Therefore, there has been a problem that long-term continuous measurement cannot be performed with this device.

The present invention has been made in order to solve such a problem, and it is possible to continuously measure the temperature of a high-temperature liquid, for example, the temperature of a molten metal in a furnace, for a long period of time by using an optical fiber, and to obtain a quick response. It is another object of the present invention to obtain a temperature measuring device using an optical fiber having good measurement accuracy.

[0009]

According to a first aspect of the present invention, there is provided a temperature measuring apparatus using an optical fiber, comprising: a radiation thermometer connected to one end of a metal tube-coated optical fiber wound around a drum; A temperature measuring nozzle arranged so as to be in contact with the high-temperature liquid, and an optical fiber supply means for automatically or continuously intermittently feeding the other end of the metal tube-coated optical fiber into the high-temperature liquid through the temperature measuring nozzle, Nozzle clogging prevention that supplies a nozzle clogging prevention gas to the tip end side of the nozzle via a gap formed between the outer circumference of the metal tube coated optical fiber and the inner circumference of the temperature measurement nozzle connected to the temperature measurement nozzle Gas supply means. The temperature measuring device using an optical fiber according to claim 2 of the present invention is the above-described claim 1.
In the temperature measuring device using an optical fiber according to the above, the optical fiber supply means includes a speed detecting means for detecting a feeding speed of the metal tube-coated optical fiber, and a feed speed control means for controlling the feed speed of the optical fiber based on an output signal of the speed detecting means. Things.

According to a third aspect of the present invention, in the temperature measuring apparatus using an optical fiber according to the first or second aspect, the optical fiber supply means melts the other end of the optical fiber coated with a metal tube. Send out according to the amount lost. The temperature measuring device using an optical fiber according to claim 4 of the present invention is the temperature measuring device using an optical fiber according to any one of claims 1 to 3, wherein the temperature measuring nozzle has a ratio of an inner diameter to an outer diameter of the metal tube-coated optical fiber. Is 1.5
３3.5.

According to a fifth aspect of the present invention, there is provided a temperature measuring apparatus using an optical fiber according to any one of the first to fourth aspects, wherein the temperature measuring nozzle is made of brick or ceramics. , A temperature measuring nozzle constituted by a single metal tube or a temperature measuring nozzle constituted by a single metal tube made of ceramic inside.

According to a sixth aspect of the present invention, there is provided a temperature measuring apparatus using an optical fiber according to any one of the first to fourth aspects, wherein the temperature measuring nozzle is made of a single metal tube or a ceramic inside. The nozzle clogging prevention gas is formed of a metal single tube and a metal tube provided outside the single tube, and is formed in a gap formed between an outer peripheral portion of the inner single tube and an inner peripheral portion of the outer metal tube. Is supplied.

According to a seventh aspect of the present invention, there is provided a temperature measuring apparatus using an optical fiber according to any one of the first to sixth aspects, wherein the gas supply means for preventing nozzle clogging is coated with a metal tube by the optical fiber supply means. Depending on the difficulty of feeding the optical fiber, an inert gas, a mixed gas of an inert gas and an oxidizing gas, or an oxidizing gas is selected and supplied as a nozzle clogging prevention gas blown into the temperature measuring nozzle. Means for selecting the type of gas to be discharged and the linear flow velocity of the gas blown out from the tip of the temperature measuring nozzle to 50 to 500 Nm
/ Sec, which controls the flow rate to a predetermined speed in the range of / sec.

According to an eighth aspect of the present invention, in the temperature measuring apparatus using an optical fiber according to any one of the first to sixth aspects, the gas supply means for preventing clogging of the nozzle comprises a nozzle blowing into the temperature measuring nozzle. Depending on the pressure of the anti-clogging gas and the sending speed of the metal tube coated optical fiber,
Gas type automatic selection means for automatically selecting and supplying any of an inert gas, a mixed gas of an inert gas and an oxidizing gas, or an oxidizing gas as a nozzle clogging prevention gas. .

According to a ninth aspect of the present invention, in the temperature measuring apparatus using an optical fiber according to any one of the first to eighth aspects, the nozzle clogging prevention gas supply means includes a nozzle clogging prevention gas flow rate. Is set in a range satisfying the following expression (1).

[0016]

(Equation 2)

Here, Q: blown gas flow rate [Nl /
min] Tm: melt temperature [K] Tl: solidification temperature of melt [K] Tg: temperature of blown gas [K] Cp: specific heat of blown gas at melt temperature [J / Kg ·
K] M: molecular weight of blown gas

[0018]

In the invention according to the first aspect, the optical fiber supply means automatically or continuously inserts the other end of the metal tube-coated optical fiber wound around the drum into the high-temperature liquid through the temperature measuring nozzle. To send out. Then, a radiation thermometer connected to one end of the metal tube-coated optical fiber measures the temperature of the high-temperature liquid. The tip of the temperature measuring nozzle is in contact with the high-temperature liquid, and is located on the tip side of the temperature measuring nozzle through a gap formed between the inner peripheral portion of the temperature measuring nozzle and the outer peripheral portion of the metal tube-coated optical fiber. The nozzle clogging prevention gas is supplied from the nozzle clogging prevention gas supply means, thereby preventing nozzle clogging. In the invention according to claim 2, the speed detecting means of the optical fiber supply means detects the feeding speed of the metal tube-coated optical fiber, and the feeding speed control means sets the feeding speed of the optical fiber to a predetermined speed based on the output signal from the speed detecting means. To control.

In the invention according to claim 3, the optical fiber supply means can continuously measure the temperature by sending out the other end of the metal tube-coated optical fiber in accordance with the amount of erosion. Has become. In the invention according to claim 4, since the ratio between the inner diameter of the temperature measuring nozzle and the outer diameter of the metal tube-coated optical fiber is in the range of 1.5 to 3.5, the tip of the temperature measuring nozzle is formed. It is possible to control the flow velocity of the gas blown out from within an appropriate range.

In the invention according to claim 5, the temperature measuring nozzle is a temperature measuring nozzle made of brick or ceramic, a temperature measuring nozzle made of a single metal tube, or a single metal tube made of ceramic inside. , It is possible to avoid fusion with the optical fiber.

In the invention according to claim 6, the temperature measuring nozzle has a double tube structure, and is provided between the outer peripheral portion of the inner single tube and the inner peripheral portion of the outer metal tube. Since the gas for preventing nozzle clogging is supplied to the gap, the durability is excellent.

In the invention according to claim 7, the gas type selecting means includes an inert gas, an inactive gas and an inactive gas as a nozzle clogging prevention gas blown into the temperature measuring nozzle according to the difficulty of sending the metal tube-coated optical fiber by the optical fiber supply means. Either a mixed gas of an active gas and an oxidizing gas or an oxidizing gas is selected and supplied. Further, the blowing velocity control means controls the linear velocity of the blowing gas at the tip of the temperature measuring nozzle in contact with the high-temperature liquid to a predetermined velocity in the range of 50 to 500 Nm / sec.

In the invention according to the eighth aspect, the gas type automatic selecting means is configured to inactive as a nozzle clogging preventing gas according to the pressure of the nozzle clogging preventing gas blown into the temperature measuring nozzle and the feeding speed of the metal tube-coated optical fiber. A gas, a mixed gas of an inert gas and an oxidizing gas, or an oxidizing gas is automatically selected and supplied.

According to the ninth aspect of the present invention, the nozzle clogging prevention gas supply means blows and supplies the nozzle clogging prevention gas to the temperature measuring nozzle. However, if the flow rate of the inert gas as the nozzle clogging prevention gas is too high, mushrooms (a sponge-like lump in which the molten metal is partially solidified) are formed at the tip of the temperature measuring nozzle, and the metal pipe is covered. Optical fiber cannot be inserted. With respect to the formation of mushrooms, it is conceivable to melt the mushrooms by blowing oxygen to enable the supply of optical fibers. However, when oxygen is blown, melting of the temperature measurement nozzle becomes a problem. In addition, a metal oxidation reaction occurs near the outlet of the temperature measurement nozzle, and the temperature measurement accuracy is deteriorated. Various experiments have been conducted on the generation of the mushroom formed at the tip of the temperature measuring nozzle. As a result, the relationship among the gas temperature, the gas type, the flow rate, the molten metal temperature, and the molten metal component was determined by the condition of the above equation (1). When satisfied, it was found that no mushrooms were formed at the tip of the temperature measuring nozzle, which would hinder temperature measurement. Therefore, by controlling the gas flow rate within the range shown by the expression (1), continuous temperature measurement can be performed while preventing generation of mushrooms. For this reason, it is not necessary to blow oxygen, and it is possible to prevent melting of the temperature measurement nozzle and a decrease in temperature measurement accuracy.

[0025]

【Example】

Embodiment 1 FIG. FIG. 1 is a block diagram showing a configuration of a temperature measuring device using an optical fiber according to one embodiment of the present invention. In FIG. 1, reference numeral 10 denotes 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 coupled to the temperature measuring nozzle 20, which allows the metal tube-coated optical fiber 11 to pass therethrough and supplies a nozzle clogging prevention gas. Reference numeral 30 denotes a nozzle clogging prevention gas supply device, which includes pressure / flow rate regulators 31 and 32, a supply gas controller 33, a supply gas generator 34, and a gas pressure detector 35. Reference numeral 40 denotes a furnace such as a converter and an electric furnace. In the illustrated example, the temperature measurement nozzle 20 is provided on the side wall of the furnace 40, but the temperature measurement nozzle 20 may be provided on the bottom of the furnace 40.

In the temperature measuring device using an optical fiber according to the present embodiment, when measuring the temperature of a high-temperature liquid, for example, the temperature of a molten metal in a furnace, the tip of the optical fiber 11 coated with a metal tube is filled with a nozzle clogging prevention gas (for example, nitrogen gas N2). Along with ₂ ), by inserting directly into the molten metal or slag in the furnace, and the tip of the metal tube-coated optical fiber 11 is eroded due to high temperature, a new optical fiber is continuously fed and supplied by the amount of the eroded fiber. This enables continuous temperature measurement. Here, the structure in which the optical fiber is covered with the metal tube is because the pressure of the gas for preventing nozzle clogging is applied to the optical fiber when the optical fiber is fed into the furnace by the optical fiber supply device 10. , To protect the optical fiber inside.

For example, a stainless steel tube is used as the metal tube covering the optical fiber. Since the melting point of this stainless steel is about 1400 to 1430 ° C., it does not immediately melt even when inserted into high-temperature molten steel, and protects the optical fiber for several seconds. In this embodiment, the optical fiber is 160
Since it is made of quartz glass having a softening point of 0 ° C. or more, its shape can be maintained without melting for a short time. Metal tube coated optical fiber 1 in this embodiment
1 has an outer diameter of 1.2 mm.

The temperature measuring nozzle 20 may be, for example, one made of brick or ceramics, one made of a single metal tube, or one made of a single metal tube with ceramic inside. A metal tube is provided concentrically outside the temperature measuring nozzle composed of a single metal tube or a single metal tube made of ceramic inside, between the outer diameter of the inner temperature measuring nozzle and the inner diameter of the outer metal tube. There is also a double pipe structure in which the provided gap is connected to the nozzle clogging prevention gas supply device 30.

One end of the temperature measuring nozzle 20 is in contact with the high-temperature liquid, and the other end is air-tightly connected to the optical fiber guide 21. The optical fiber 11 coated with the metal tube is inserted through the optical fiber guide 21 and inserted into the high-temperature liquid. . Further, the inner diameter of the temperature measuring nozzle 20 and the optical fiber
A gap is provided between the outer diameter of the nozzle and the outer diameter of the nozzle 1, and a gas for preventing nozzle clogging is blown into the gap via the optical fiber guide 21.

FIG. 2 is a view showing an example of a temperature measuring nozzle constituted by a single metal tube made of ceramics inside in this embodiment. The temperature measuring nozzle 20 in FIG. 2 has a structure in which a ceramic tube 20b is arranged inside a stainless steel tube 20a. In this example, SUS304 was used as the material of the stainless steel tube 20a, and silicon nitride (Si ₃ N ₄ ) was used as the material of the ceramic tube 20b. However, the ceramic is not limited to this, and boron nitride (boron nitride) is used. BN), zirconium oxide (ZrO ₂ ), or the like may be used. Instead of the ceramic tube, a metal tube having a ceramic coating on the inner surface may be used.

Here, the reason why the ceramic tube 20b is arranged inside the stainless steel tube 20a will be described. When the temperature measuring nozzle 20 is only the stainless steel tube 20a, the coating tube (stainless steel tube) of the optical fiber and the temperature measuring nozzle 20 are fused during the temperature measurement, and the feeding of the metal tube coated optical fiber 11 is stopped. Continuous measurement of temperature may not be possible. In order to avoid this inconvenience, by adopting a structure in which the ceramic tube 20b is disposed inside, the temperature measuring nozzle 20 and the cladding tube of the optical fiber are not fused.

The stainless steel tube 2 in the embodiment shown in FIG.
The temperature measuring nozzle 20 composed of the ceramic tube 20a and the ceramic tube 20b had an inner diameter of 4.0 mm, an outer diameter of 8.0 mm, and a length of about 1000 mm. In the case of a single tube nozzle made of stainless steel (for example, SUS304), an inner diameter of about 2.0 mm and an outer diameter of about 4.0 mm were used.

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

One end of the optical fiber guide 21 is airtightly connected to one end of the temperature measuring nozzle 20 which is not in contact with the high-temperature liquid, and the other end can pass through the metal tube-coated optical fiber 11, but the gas for preventing nozzle clogging is supplied to the optical fiber supply device. 1
It has a highly airtight structure provided with, for example, a double seal or the like so as not to leak to the 0 side. In addition, a pipe from a nozzle clogging prevention gas supply device 30 is connected to a gap 20d provided between the inner diameter of the optical fiber guide 21 and the outer diameter of the metal tube-coated optical fiber 11, and the gas is supplied. Although the optical fiber guide 21 is formed of a member different from that of the temperature measuring nozzle 20 in this manner, the function of sending the optical fiber together with the gas for preventing nozzle clogging into the furnace 40 is exactly the same. It can be regarded as a member constituting a part.

From the temperature measuring nozzle 20 airtightly connected to the optical fiber guide 21,
The nozzle clogging prevention gas is blown into the molten metal in the furnace 40 together with the supply of the molten metal. 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-coated optical fiber 11 enters the bubble generating region, the temperature measurement accuracy is reduced. Accordingly, for example, the temperature measurement nozzle 20 is inclined downward (for example, 3 degrees) below the horizontal plane.
(Approximately 0 degrees) so as to prevent the tip of the metal tube-coated optical fiber 11 from entering the gas floating region.

The optical fiber supply device 10 has a function of continuously or intermittently sending the metal tube-coated optical fiber 11 into the furnace 40 via the optical fiber guide 21 and the temperature measuring nozzle 20. For this reason, the feed controller 14
Drives the motor 12 and drives the motor 12 to wind the metal tube-coated optical fiber 11 wound in the optical fiber drum 16 in advance.
In this case, the feed speed of the optical fiber is detected by the feed speed detector 15, 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 set to 5 mm / sec, the intermittent feeding speed is set to 10 mm / sec for 10 seconds, and then the optical fiber is fed for 20 seconds.
The operation of stopping for a second is repeated. The tip of the optical fiber 11 coated with a metal tube inserted into the furnace 40 together with the nozzle clogging prevention gas is
As time passes, the fiber is eroded, so that the amount of the eroded fiber (i.e., the consumed amount) is constantly supplied with new optical fiber. By continuously supplying this new optical fiber, continuous temperature measurement becomes possible.

The feed rate detector 15 can determine the feed rate from, for example, the rotation angle of the sensor roller within a unit time, and this detection signal is supplied to the feed controller 14 and the supply gas controller in the nozzle clogging prevention gas supply device 30. 33. And this feed speed detector 1
The difficulty state of sending out the optical fiber can be determined based on whether the detection value of No. 5 is within the normal range. For example, when the tip of the temperature measurement nozzle 20 becomes clogged, the feed speed decreases. When the feed speed falls below the normal range, the feed controller 14 stops driving the motor 12 to prevent the device from malfunctioning.

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

The radiation thermometer 17 includes, for example, a two-color thermometer for obtaining a temperature by comparing the luminance output of two wavelengths and an infrared radiation thermometer for directly obtaining a temperature from the luminance output of the radiated light. The temperature is calculated from the signal in accordance with each measurement method, and the calculated temperature signal is output as an electric signal and supplied to, for example, a recorder (not shown).

The gas supplied by the nozzle clogging prevention gas supply device 30 to the optical fiber guide 21 includes an inert gas (nitrogen gas in this example), an oxidizing gas (oxygen gas in this example), and an inert gas and an oxidizing gas. (This mixture ratio can be variably set), and any one of three types of gases is selected and used. The selection of this gas type
The operation is performed manually or automatically depending on the difficulty of sending 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 includes a detection signal of the gas pressure detector 35 and a feed speed detector 1 in the optical fiber supply device 10.
5, and automatically selects one of the three types of nozzle clogging prevention gas in accordance with the values of the two detection signals. It is supplied to adjusters 31 and 32.

The pressure / flow rate regulators 31 and 32 include a pressure regulator, a flow rate regulator, a control valve, and the like. The input nitrogen gas and oxygen gas are converted into pressure and flow rate according to the control signal. The gas is supplied to the supply gas generator 34. In the supply gas generation unit 34, one of a nitrogen gas, an oxygen gas, or a mixed gas of the two is generated at a predetermined pressure, and is supplied to the optical fiber guide 21 therefrom.

The gas pressure detector 35 is connected to the supply gas generator 3
4 detects the gas pressure supplied to the optical fiber guide 21 and supplies the detected value to the supply gas controller 33. This is because, when the tip of the temperature measuring nozzle 20 becomes clogged, the amount of gas to be supplied decreases, and the detected value of the gas pressure increases. Therefore, it is determined whether the detected value is within the normal range. This is because the clogged state of the tip of the warm nozzle 20 can be determined. The supply gas controller 33 determines the clogging state of the tip of the temperature measuring nozzle 20 based on the supply gas pressure detection value and the optical fiber feed speed detection value, and automatically selects the gas type.

In the embodiment shown in FIG. 1, when the detected value of the optical fiber feed speed and the detected value of the supplied gas pressure are within the normal range, the supply gas controller 33 controls the coating of the metal tube inserted into the temperature measuring nozzle 20 and the furnace 40. In order to protect the optical fiber 11, an inert gas having a cooling effect (nitrogen gas in FIG. 1) is selected as a gas for preventing nozzle clogging.
However, when the flow rate of the inert gas is too large, mushrooms (sponge-like masses in which the molten metal is partially solidified) are generated at the tip of the temperature measuring nozzle 20, and the insertion of the metal tube-coated optical fiber 11 is performed. Can not be done. On the other hand, when the flow rate of the inert gas is too small, the molten metal is inserted into the tip of the temperature measurement nozzle 20.

In the embodiment of FIG. 1, the amount of nitrogen gas blown into the optical fiber guide 21 adjusted by the pressure / flow cooker 31 is 5.0 Nm ³ / Hr (1389 cc).
/ Sec), and the linear flow velocity of the gas at the tip of the temperature measuring nozzle 20 is adjusted to be an optimum value within the range of 50 to 500 Nm / sec. In order to secure this linear flow velocity, 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 most preferably in the range of approximately 1.5 to 3.5.

Even when the temperature is measured by injecting nitrogen gas as described above, the feed speed of the optical fiber is reduced due to the formation of mushrooms at the tip of the temperature measuring nozzle 20 in the furnace 40, and the supply gas pressure is increased. Sometimes. In this case, the supply gas controller 33 selects, as the nozzle clogging prevention gas, a mixed gas obtained by mixing oxygen gas with nitrogen gas at a predetermined ratio. The mixing ratio of the mixed gas can be variably set, but it is generally preferable to limit the mixing ratio of the oxygen gas to at most 50% from the viewpoint of protection of the temperature measuring nozzle 20.

The supply gas controller 33 controls the pressure / flow rate regulators 31 and 32 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 remove mushrooms and the like. It can be dissolved to prevent its adhesion. However,
When the mixed gas is blown out due to strong mushroom adhesion or the like, the feed speed of the optical fiber and the supply gas pressure may not return to the normal range. In this case, the supply gas controller 33 sets the shortage as a gas for preventing nozzle clogging. Oxygen gas is selected only for a certain time, and dissolution by this oxygen gas is performed.

FIG. 3 is a diagram showing an example of a temperature measurement result using an optical fiber in a certain converter under the following measurement conditions. (1) Temperature measuring nozzle, Model: Composite single tube nozzle Inner / outer diameter of nozzle: 4.0 mm / 8.0 mm Material: SUS304 + Si ₃ N ₄ (2) Optical fiber, structure: Stainless steel tube coating Outer diameter: 1.2 mm ( 3) Gas blowing, Type: Nitrogen gas Blowing amount: 5.0 Nm ³ / Hr Blowing flow rate: 121 Nm / sec (4) Optical fiber feeding speed: 5 mm / sec (continuous) or 10 mm / sec (intermittent)

In FIG. 3, the waveform fluctuating up and down 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 is 4 ° C. on average.
Met. Here, an error of 4 ° C. with respect to the measurement temperature of 1600 ° C.
Has a measurement accuracy of 0.25%, which is quite good.

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 in the case of intermittent sending of 10 mm / sec for 10 seconds and then stopping for 20 seconds. Also, as nozzle clogging gas,
By performing the injection of the mixed gas of the nitrogen gas and the oxygen gas as necessary, the trouble of stopping the insertion of the optical fiber did not occur.

FIG. 4 is a graph showing a comparison between the indicated value of the thermocouple (T _s ) and the indicated value of the optical fiber thermometer (T _f ). The horizontal axis indicates T _s , the vertical axis indicates T _f, and the measurement using an optical fiber. The values are indicated by squares. The □ marks in FIG. 4 are substantially distributed on a straight line of T _s = T _f , indicating that the measurement results are good.

Embodiment 2 FIG. FIG. 5 is a block diagram showing a configuration of a temperature measuring device using an optical fiber according to one embodiment of the present invention. In this embodiment, in contrast to the embodiment of FIG. 1, the pressure / flow rate adjusting device 32 for adjusting the pressure / flow rate of the oxygen gas is omitted, and the oxygen gas is not supplied. Instead, as described later, the pressure / flow rate adjusting device 31 adjusts the flow rate of the nitrogen gas so as to be within a certain range.

FIG. 6 is a diagram showing an example of a temperature measurement result using an optical fiber in a certain converter under the following measurement conditions. (1) Temperature measuring nozzle, Model: Composite single tube nozzle Inner / outer diameter of nozzle: 3.0 mm / 7.0 mm Material: SUS304 + Si ₃ N ₄ (2) Optical fiber, structure: Stainless steel tube coating Outer diameter: 1.2 mm ( 3) Gas blowing, Type: Nitrogen gas Blowing amount: 2 to 20.9 Nm ³ / Hr (4) Optical fiber feed rate: 5 mm / sec (continuous) or 10 mm / sec (intermittent) (5) Melting [C]: 4.2% to 0.02% Temperature: 1250 to 1650 ° C

In FIG. 6, the waveform fluctuating up and down 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 is 4 ° C. on average.
Met. Here, an error of 4 ° C. relative to the measurement temperature of 1600 ° C.
Is a measurement accuracy of 0.25%, and similar to the example of FIG.
The accuracy was quite good. The feed rate of the optical fiber is 5 mm / sec continuously and 10 mm / sec.
For about 10 seconds, and then intermittently for 20 seconds, almost the same measurement results were obtained.

FIG. 7 is a diagram showing a comparison between the indicated value of the thermocouple (T _s ) and the indicated value of the optical fiber thermometer (T _f ), where T _s is plotted on the horizontal axis and T _f is plotted on the vertical axis. The values are indicated by squares. The □ marks in FIG. 7 are substantially distributed on the straight line of T _s = T _f , indicating that the measurement results are good.

FIG. 8 shows the embodiment of FIG. 5 in which the flow rate of the blown gas is maintained under the condition of equation (1) and the other cases (only nitrogen gas is supplied and the condition of equation (1) is not maintained). FIG. 7 is a diagram showing a comparison of the frequency at which the feeding of the fiber is stopped). It can be seen from the figure that stable measurement is possible according to the present invention.

[0058]

According to the present invention (claim 1), when measuring the temperature of the high-temperature liquid, the distal end (the other end) of the metal tube-coated optical fiber is passed through the temperature measuring nozzle together with the nozzle clogging prevention gas. Directly inserted into the high-temperature liquid, it is possible to continuously send out and supply a new optical fiber as much as the tip of the optical fiber is damaged by the high temperature, so long-term continuous measurement is possible and responsiveness is fast. It is possible to obtain a temperature measuring device using an optical fiber having good measurement accuracy. Further, according to the present invention (claim 2), the feeding speed of the metal tube-coated optical fiber can be controlled to a predetermined speed, so that the feeding operation of the metal tube-coated optical fiber becomes stable.

Further, according to the present invention (claim 3), the other end of the metal tube-coated optical fiber is sent out in accordance with the amount of the erosion, whereby a new optical fiber is continuously supplied by the amount of the erosion. Therefore, it is possible to continuously measure the temperature over a long period of time. According to the present invention (claim 4), the ratio of the inner diameter of the temperature measuring nozzle to the outer diameter of the metal tube-coated optical fiber is 1.5 to 1.5.
Since it was set to be in the range of 3.5, the linear velocity of the blown gas at the tip of the temperature measuring nozzle was set to, for example, 50 to 500 Nm / s.
The speed can be controlled to a predetermined value within the range of ec.

According to the present invention (claim 5), it is possible to use a temperature measuring nozzle composed of brick or ceramics or a temperature measuring nozzle composed of a single metal tube made of ceramic inside. Thus, an accident in which the optical fiber cladding tube and the temperature measuring nozzle are fused and the feeding of the optical fiber is stopped can be avoided.

According to the present invention (claim 6), a double pipe further provided with a metal pipe outside the temperature measuring nozzle constituted by a single metal pipe or a single metal pipe made of ceramic inside. As the temperature measuring nozzle of the structure, the nozzle clogging prevention gas is blown out from the gap between the inner temperature measuring nozzle and the outer metal tube, so the durability of the temperature measuring nozzle is improved,
Long-term use has become possible.

According to the present invention (claim 7), as the nozzle clogging preventing gas, an inert gas having a cooling effect, a mixed gas of an inert gas having a dissolving effect such as mushroom and an oxidizing gas, or an oxidizing gas. Since any one of the reactive gases can be selected and supplied, the tip of the temperature measuring nozzle is not clogged by the adhesion of the mushroom or the like during the measurement, and it becomes difficult to feed the optical fiber.

Further, according to the present invention (claim 8), the above-mentioned 3 which is blown into the temperature measuring nozzle according to the pressure of the nozzle clogging prevention gas blown into the temperature measuring nozzle and the feed speed of the optical fiber.
Since any one of the types of nozzle clogging prevention gas is automatically selected and supplied, labor can be saved in the measurement operation for long-term continuous measurement, and automatic measurement can be performed.

According to the present invention (claim 9), when measuring the temperature of the high-temperature liquid, the generation of mushrooms at the nozzle tip can be prevented by appropriately controlling the flow rate of the gas for preventing nozzle clogging. Therefore, a long-term continuous measurement is possible, and the responsiveness is fast and the temperature measurement of the high-temperature liquid by the optical fiber with good measurement accuracy is possible.

[Brief description of the drawings]

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

FIG. 2 is a view showing an example of a temperature measuring nozzle constituted by a single tube of a metal whose inside is ceramics in the embodiment of FIG. 1;

FIG. 3 is a diagram illustrating an example of a temperature measurement result according to the embodiment of FIG. 1;

FIG. 4 is a diagram illustrating a comparison between a thermocouple command value and an optical fiber thermometer command value according to the embodiment of FIG. 1;

FIG. 5 is a block diagram showing a configuration of a temperature measuring device using an optical fiber according to one embodiment of the present invention.

FIG. 6 is a diagram illustrating an example of a temperature measurement result according to the embodiment of FIG. 5;

FIG. 7 is a diagram showing a comparison between a thermocouple command value and an optical fiber thermometer command value according to the embodiment of FIG. 5;

FIG. 8 is a diagram showing a nozzle clogging prevention effect according to the embodiment of FIG. 5;

[Explanation of symbols]

 Reference Signs List 10 optical fiber feeding device 11 metal tube coated optical fiber 12 motor 13 roller 14 feed controller 15 feed speed detector 16 optical fiber drum 17 radiation thermometer 20 temperature measuring nozzle 21 optical fiber guide 30 nozzle gas preventing device for nozzle clogging 31, 32 pressure / flow rate regulator 33 supply gas controller 34 supply gas generator 35 gas pressure detector 40 furnace

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masaki Komagani 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Genji Kanaya 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Masao Hiroko, 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Takafumi Yoshikawa 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan stock Inside the company (72) Inventor Masashi Edahiro 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Masanori Suebo 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Yoshimi Komatsu 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Inside Nippon Kokan Co., Ltd. (72) Inventor Akihiko Inoue Maru, Chiyoda-ku, Tokyo 1-2-1, Nippon Kokan Co., Ltd. (72) Inventor Hideaki Mizukami 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Tsuyoshi Murai 1-1-1, Marunouchi, Chiyoda-ku, Tokyo No. 2 Inside Nippon Kokan Co., Ltd. (56) References JP-A-5-248960 (JP, A) JP-A-62-132135 (JP, A) JP-A-60-61633 (JP, A) JP-A Sho-63 -230815 (JP, A) JP-A-60-129628 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01J 5/00-5/62 G01J 1/00-1/46

Claims (9)

(57) [Claims] 1. A radiation thermometer connected to one end of a metal tube-coated optical fiber wound on a drum; a temperature measurement nozzle arranged so that a tip portion is in contact with a high-temperature liquid; An optical fiber supply means for automatically or continuously intermittently feeding the other end of the optical fiber into the high-temperature liquid through the temperature measuring nozzle; and an outer peripheral portion of the metal tube-coated optical fiber connected to the temperature measuring nozzle. A nozzle clogging prevention gas supply unit for supplying a nozzle clogging prevention gas to a tip end side of the nozzle through an air gap formed between the temperature measurement nozzle and an inner peripheral portion thereof. Temperature measuring device. 2. The optical fiber supply means includes a speed detecting means for detecting a feeding speed of the metal tube-coated optical fiber, and a feeding speed control means for controlling a feeding speed of the optical fiber based on an output signal of the speed detecting means. The temperature measuring device using an optical fiber according to claim 1. 3. The optical fiber temperature measuring device according to claim 1, wherein the optical fiber supply means sends out the other end of the metal tube-coated optical fiber according to the amount of erosion. 4. The temperature measuring nozzle according to claim 1, wherein a ratio of an inner diameter of the temperature measuring nozzle to an outer diameter of the metal tube-coated optical fiber is in a range of 1.5 to 3.5. A temperature measuring device using an optical fiber according to any one of claims 1 to 3. 5. A temperature measuring nozzle formed of a brick or ceramic, a temperature measuring nozzle formed of a single metal tube, or a temperature measuring nozzle formed of a single metal tube made of ceramic inside. The temperature measuring device using an optical fiber according to any one of claims 1 to 4, comprising a nozzle. 6. The temperature measuring nozzle comprises a single metal tube or a single metal tube made of ceramic inside, and a metal tube provided outside the single tube. 2. The nozzle clogging prevention gas is supplied to a gap formed between the outer circumference of the metal pipe and an inner circumference of the outer metal pipe.
A temperature measuring device using an optical fiber according to any one of claims 1 to 5. 7. The nozzle clogging prevention gas supply means includes an inert gas, an inert gas, and an oxidizing gas as the nozzle clogging prevention gas according to the difficulty of sending the metal tube-coated optical fiber by the optical fiber supply means. A gas type selecting means for selecting and supplying either a mixed gas or an oxidizing gas; and setting a linear flow velocity of the gas blown out from the tip of the temperature measuring nozzle to 50.
7. An optical fiber-based temperature measuring device according to claim 1, further comprising: a blow-off flow rate control means for controlling the flow rate to a predetermined speed in a range of from about 500 Nm / sec to about 500 Nm / sec. 8. The nozzle clogging prevention gas supply means, as the nozzle clogging prevention gas according to the pressure of the nozzle clogging prevention gas blown into the temperature measuring nozzle and the feeding speed of the metal tube-coated optical fiber by the optical fiber supply means. A gas type automatic selecting means for automatically selecting and supplying any one of an inert gas, a mixed gas of an inert gas and an oxidizing gas, or an oxidizing gas. A temperature measuring device using an optical fiber according to claim 6. 9. The method according to claim 1, wherein said nozzle clogging prevention gas supply means sets a nozzle clogging prevention gas flow rate in a range satisfying the following expression (1). Temperature measuring device using optical fiber. (Equation 1) Here, Q: blown gas flow rate [Nl / min] Tm: melt temperature [K] Tl: solidification temperature of melt [K] Tg: temperature of blown gas [K] Cp: specific heat of blown gas at melt temperature [J] / Kg ・
K] M: molecular weight of blown gas