JP2009287965A - Molten metal measuring device - Google Patents

Abstract

In a measurement apparatus for a molten metal that measures a molten metal having suspended matter on the surface, the measurement accuracy is improved by improving the daylighting rate.
A measuring apparatus 10 for molten metal according to the present invention is a measuring instrument that performs at least one of component analysis and temperature measurement of molten metal M based on light emission from molten metal M having suspended matter S on its surface. 11 and a cylindrical member 100 that transmits light emitted from the molten metal M to the measuring instrument 11, and the cylindrical member 100 has one end immersed in the molten metal M and the other end connected to the measuring unit 11. A reflection surface 110a that reflects light emitted from the molten metal M is provided on the inner surface side.
[Selection] Figure 1

Description

  The present invention relates to a measurement apparatus for molten metal, and more particularly to a measurement apparatus for molten metal that performs component analysis and temperature measurement of a molten metal having suspended matter on the surface.

  In measurements using light emission and light absorption on the molten metal surface, such as measurement of molten metal components and radiation temperature measurement, it is important to obtain a clean liquid surface by removing suspended substances such as slag in order to improve measurement accuracy. It is.

  As a method of obtaining a clean liquid surface by removing such suspended matter such as slag, for example, a method of immersing a part of a probe that transmits measurement light from a molten metal liquid surface to an optical system that receives the measurement light It has been proposed (see, for example, Patent Documents 1 and 2). In the case of these probes, the transmission of measurement light in the probe is a spatial transmission.

JP 2006-300819 A JP 2002-98685 A JP 56-128445 A JP-A-1-299423 JP 2004-37163 A JP 58-189527 A

  However, in the probes described in Patent Documents 1 and 2, when the optical system is heated by radiation from the molten metal, the measurement result is affected. Therefore, it is necessary to increase the distance from the molten metal to the optical system to some extent. As a result, the light collection rate of the measurement light by the optical system is low, and it has not yet been put into practical use.

  Also, a method of reflecting light within a probe that transmits measurement light has been proposed in order to increase the light collection rate of measurement light by an optical system (see, for example, Patent Document 3). However, in this case, since the probe cannot be immersed and it is necessary to take a certain distance from the molten metal as in the case of Patent Documents 1 and 2, it has not been put into practical use.

  On the other hand, as a conventional temperature measurement technique, a method of directly measuring temperature by immersing a consumable immersion thermocouple in molten metal, a method of measuring by radiation temperature measurement from an opening such as a tuyere installed in a refining vessel, etc. was there.

  However, when measuring with a consumable immersion thermocouple, there is a problem that continuous temperature measurement is impossible, and the thermocouple is disposable, which is costly.

  There is also a temperature measurement technique using a continuous immersion thermocouple using a refractory protection tube (see, for example, Patent Document 4). In this case, since the protective tube cannot be cooled, high heat resistance and high corrosion resistance are required as materials, and high thermal conductivity is also required to increase the response speed. Therefore, only a part of special refractories can be used, and there is a problem that the cost increases.

  On the other hand, when measuring by radiation temperature measurement from a tuyere or the like (see, for example, Patent Document 5), it is necessary to keep a certain distance from the surface of the molten metal in order to prevent the measuring instrument from being damaged by heat. Therefore, there is a problem that the amount of radiant light that can be used for measurement is limited, and the lighting rate is low. In addition, when a temperature measurement is performed by inserting a cylindrical measurement probe from above the ladle (see, for example, Patent Document 6), the optical system is placed at a certain distance from the molten metal surface as in the case of component analysis. In this case, there was a problem that the daylighting rate was low.

  Therefore, the present invention has been made in view of such circumstances, and in a measuring apparatus for molten metal that measures a molten metal having suspended matter on the surface, the measurement accuracy is improved by improving the daylighting rate. With the goal.

  Furthermore, when applying this invention to a temperature measurement technique, it aims at making the measuring apparatus for molten metals continuously usable.

  As a result of intensive studies to solve the above problems, the present inventors reflect the measurement light on the inner surface of a cylindrical member such as a probe that transmits light emitted from the molten metal (measurement light) to the measuring device. By providing the reflecting surface, it is possible to reflect the measuring light on the inner surface of the cylindrical member and collect the measuring light diverging around in the conventional method, so that the measuring light sampling rate can be improved. I found.

  Further, as a result of further investigation, the present inventors have provided a cooling means for cooling the reflection surface provided on the inner surface side of the cylindrical member, thereby reducing the reflectance on the reflection surface due to heat reception from the molten metal. It was found that the growth of the metal on the outer surface of the tubular member can be suppressed, and the operability of the molten metal measuring device can be improved.

  The present invention has been completed based on the above findings, and the gist thereof is as follows.

  That is, according to the present invention, a measuring device that performs at least one of component analysis and temperature measurement of the molten metal based on light emission from the molten metal having a suspended substance on the surface, and light emission from the molten metal A cylindrical member that transmits to the measuring device, and the cylindrical member has one end immersed in the molten metal, the other end connected to the measuring unit, and a reflection that reflects the light emission to the inner surface side. A measuring device for molten metal having a surface is provided.

  Here, the reflection surface has an end on the molten metal side with respect to the transmission direction of the light emission on the reflection surface, and an end on the molten metal side with respect to the transmission direction of the light emission on the cylindrical member. The ratio between the distance H between the end of the reflecting surface on the molten metal side and the end of the cylindrical member on the molten metal side, and the inner diameter D of the cylindrical member is: It is preferable that 0 <H / D ≦ 10.

  Moreover, it is preferable that the said cylindrical member has a cooling means to cool at least the said reflective surface.

  Further, the cylindrical member has the reflection surface on the inner surface side, and transmits a light transmission tube that transmits the light emission, an inner tube coaxially provided outside the light transmission tube, and an outer side of the inner tube. An outer tube provided coaxially, and a cooling tube formed by, and a refractory layer covering a part or all of the outer surface of the light transmission tube and the cooling tube, the inner tube and the The outer pipe may communicate with one end, a cooling medium may be supplied from the other end of the inner pipe, and the cooling medium may be discharged from the other end of the outer pipe.

  In this case, it is preferable that a cooling fin is provided in a supply side flow path of the cooling medium formed by the outer surface of the light transmission tube and the inner surface of the inner tube.

  The cross-sectional area of the cooling medium discharge-side flow path formed by the outer surface of the inner tube and the inner surface of the outer tube is the cooling formed by the outer surface of the light transmission tube and the inner surface of the inner tube. It is preferably larger than the cross-sectional area of the medium supply side flow path.

  The outer tube has a tapered shape in which the diameter on the measurement unit side is larger than the diameter on the molten metal side with respect to the transmission direction of the light emission, and the light transmission direction of the cylindrical member The cross-sectional area of the discharge side flow path of the cooling medium formed by the outer surface of the inner tube and the inner surface of the outer tube at the end on the measurement unit side is the outer surface of the light transmitting tube and the inner surface of the light transmitting tube. It is preferable that it is larger than the cross-sectional area of the supply-side flow path of the cooling medium formed by the inner surface of the pipe.

  Further, the thermal conductivity, outer diameter, and inner diameter of the refractory layer may be determined according to desired inner surface temperature and outer surface temperature of the refractory layer.

  Moreover, it is preferable that the said refractory layer has a space | gap inside.

  Moreover, the said reflective surface can be formed, for example with the stainless steel by which the mirror surface process was given.

  According to the present invention, in the measuring apparatus for molten metal that measures the molten metal having floating substances on the surface, the lighting rate is improved by providing the reflecting surface that reflects the light emitted from the molten metal on the inner surface side of the cylindrical member. This can improve the measurement accuracy.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

[First Embodiment]
(Overall configuration of measuring device for molten metal)
First, an overall configuration of an emission spectroscopic analyzer 10 that performs component analysis in molten metal will be described as an example of a molten metal measuring apparatus according to a first embodiment of the present invention with reference to FIG. FIG. 1 is an explanatory diagram showing the overall configuration of the emission spectroscopic analysis apparatus 10 according to the present embodiment.

  As shown in FIG. 1, the emission spectroscopic analysis apparatus 10 mainly includes a measuring instrument 11, an optical system 13, and a cylindrical member 100. In the following description, the molten steel M will be described as an example of the molten metal, and the slag S will be described as an example of the floating material on the surface of the molten metal.

  The measuring device 11 performs component analysis in the molten steel M based on light emission (measurement light L) from the molten steel M having floating substances such as slag S on the surface charged in the molten steel pan 20. As this measuring device 11, for example, when using laser-induced fluorescence analysis, a light amount detector that detects the fluorescence from the molten steel M generated by laser irradiation and measures the amount of fluorescent light can be cited. .

  The optical system 13 receives light emitted from the molten steel M (measurement light L) and introduces the received measurement light L into the measuring instrument 11. In this embodiment, the measurement light L is reflected on the mirror 15 installed above the tubular member 100 (on the opposite side to the molten steel M with respect to the transmission direction of the measurement light L), and the measurement light L is introduced into the measuring instrument 11. is doing. In the present embodiment, the optical system 13 also serves as a connection portion between the measurement unit 11 and the cylindrical member 100.

  As will be described later, the measurement light L is reflected inside the cylindrical member 100. The “transmission direction of the measurement light L (light emission from the molten steel M)” here refers to the transmission of the measurement light L. Means the direction (in the example of FIG. 1, upward in the vertical direction, which is the direction of the mirror 15).

  The tubular member 100 collects light emitted from the molten steel M (measurement light L) and transmits the measurement light L to the measuring instrument 11 via the optical system 13. The tubular member 100 has, for example, a straight tubular shape, and a front end portion (an end portion on the lower side in the vertical direction in the example of FIG. 1) is immersed in the molten steel M and a rear end portion (FIG. 1). In this example, the upper end portion in the vertical direction) is connected to the measuring instrument 11 via the optical system 13. Thus, since the front-end | tip part of the cylindrical member 100 avoids floating substances, such as slag S, and is immersed in the molten steel M located under the slag S, the cylindrical member 100 is clean of the molten steel M. Luminescence from the liquid surface can be collected, and the accuracy of component analysis of the molten steel M can be improved.

  Further, the cylindrical member 100 has a reflection surface 110 a that reflects the measurement light L on the inner surface side of the cylinder main body 110. In the emission spectroscopic analysis apparatus 10, the cylindrical member 100 has the reflecting surface 110a, so that the measuring light L is reflected by the inner surface of the cylindrical member 100 and diverges to the surroundings in the conventional method. Can be collected. Therefore, according to the emission spectroscopic analysis apparatus 10, it is possible to improve the lighting rate of the measurement light L and further improve the accuracy of component analysis of the molten steel M by the emission spectroscopic analysis apparatus 10.

  Such a reflective surface 110a can be formed using, for example, stainless steel (SUS) that has been subjected to mirror finishing as described later.

  In addition, in the case of component analysis of the molten steel M using the emission spectroscopic analyzer 10, non-oxidation of argon, nitrogen, or the like toward the molten steel M (in the example of FIG. 1, downward in the vertical direction) inside the cylinder main body 110. By blowing the property gas, the molten steel M is prevented from entering the inside of the tubular member 100, and the deterioration of the tubular member 100 is suppressed. In addition, by blowing the non-oxidizing gas in this manner, a lighting surface for collecting light emitted from the molten steel M can be formed in the opening at the lower end of the tubular member 100.

(Configuration of tubular member 100)
Next, the configuration of the cylindrical member 100 according to the present embodiment will be described in detail with reference to FIG. FIG. 2 is an explanatory diagram showing the configuration of the tubular member 100 according to the present embodiment.

  As shown in FIG. 2, the tubular member 100 mainly includes a light transmission tube 111, a cooling tube formed by the inner tube 113 and the outer tube 115, and a refractory layer 117. That is, the cylindrical member 100 has a triple tube structure including a light transmission tube 111, an inner tube 113, and an outer tube 115.

  The light transmission tube 111 has a reflection surface 110a on the inner surface side, and transmits light emitted from the molten steel M. In this light transmission tube 111, the end on the molten steel M side with respect to the transmission direction of light emission from the molten steel M is distanced from the end on the molten steel M side with respect to the transmission direction of light emission from the molten steel M in the tubular member 100. They are separated by H. Therefore, the reflecting surface 110a is also located at the end on the molten steel M side with respect to the transmission direction of light emission from the molten steel M and from the end on the molten steel M side with respect to the transmission direction of light emission from the molten steel M in the tubular member 100. They are separated by H.

  Further, the distance H (mm) between the end of the light transmission tube 111 (or the reflecting surface 110a) on the molten steel M side and the end of the tubular member 100 on the molten steel M side, and the inner diameter of the tubular member 100, that is, the transmission H / D, which is a ratio to the inner diameter D (mm) of the optical tube 111, is preferably 0 <H / D ≦ 10. Here, the range of the appropriate value of H / D will be described with reference to FIG. FIG. 3 is an explanatory diagram for explaining an appropriate value of H / D according to the present embodiment.

As shown in FIG. 3, Okuhikarikan 111 having a reflecting surface 110a are collected radiation _{L R} from the molten steel M. In this case, among the emitted light L _R, from entering the inner surface at a reflecting surface 110a of the Okuhikarikan 111 is light in a range of divergence angle θ shown in FIG. Generally, in order to perform analysis with good accuracy in component analysis of molten metal, it is preferable to secure a lighting rate of 0.1% or more. Here, lighting _rate, the solid angle of the emitted light _{L R} for generating the _{I total} from a point on the surface of the molten steel M as (= 2 [pi steradians), the inner surface of the Okuhikarikan 111 of synchrotron radiation I _{L R} When solid angle of the emitted light _{L R} that is incident to a reflecting surface 110a (= 2π (1-cosθ ) steradian), as defined in "lighting ratio _{= I / I total".} That is, in order to perform analysis with good accuracy, it is preferable that I / I _total ≧ 0.1. At this time, since cos θ = (H / D) / √ ((H / D) ² +1/4), H / D ≦ 10.

  On the other hand, the smaller the value of H / D, the better. However, when H / D = 0, the molten steel M and the light transmission tube 111 come into contact with each other, so that H / D> 0.

Next, the relationship between H / D and measurement accuracy will be described with reference to FIG. FIG. 4 is a graph showing an example of the relationship between the SN ratio (dB) and H / D in the present embodiment. In this example, it is assumed that the signal intensity I _signal is 1 when the light collection rate by the light transmission tube 111 is 100%, and that the noise intensity I _noise is reduced according to the light collection rate when the value of H / D is increased. It was calculated assuming that it was constant at 10 ⁻⁶ regardless of H / D. The SN ratio was calculated by the formula of 10 × log (I _signal / I _noise ). Note that the higher the SN ratio, the higher the measurement accuracy in component analysis.

  As a result, as shown in FIG. 4, it was found that as the H / D increases, the SN ratio decreases, that is, the measurement accuracy deteriorates. In general, it is said that if the SN ratio is 30 or more, it has sufficient measurement accuracy. However, in this example, when the H / D is 10 or less, the SN ratio is 30 or more. .

  Again, description of the configuration of the tubular member 100 will be continued with reference to FIG. The cooling tube according to the present embodiment is an example of a cooling unit that cools at least the reflecting surface 110a on the inner surface of the light transmission tube 111, and is formed by the inner tube 113 and the outer tube 115 as described above.

  The inner tube 113 is provided coaxially outside the light transmission tube 111, and the outer tube 115 is provided coaxially outside the inner tube 113. In addition, the inner tube 113 and the outer tube 115 communicate with each other at the end portion on the molten steel M side in the transmission direction of the measurement light L (in this embodiment, the lower end portion in the vertical direction). Then, the cooling medium is supplied from the end on the measuring instrument 11 side (in this embodiment, the upper end in the vertical direction) with respect to the transmission direction of the measuring light L of the inner tube 113, and the end of the outer pipe 115 on the measuring instrument 11 side. The cooling medium is discharged from the section. As described above, the cooling medium flows in the cooling pipe, whereby the reflecting surface 110a on the inner surface of the light transmission pipe 111 is mainly cooled. In addition, although it does not specifically limit as a cooling medium used in this embodiment, For example, cooling gas, cooling water, etc., such as air, water vapor | steam, non-oxidizing gas, etc. are mentioned.

  As the material for the light transmission tube 111, the inner tube 113, and the outer tube 115 described above, it is preferable to use stainless steel having excellent heat resistance. In particular, since the light transmission tube 111 has a reflective surface 110a such as a mirror surface on the inner surface, Ni-based (Ni-rich) stainless steel (for example, SUS304, SUS316, etc.) excellent in reflectivity and gloss is used. It is preferable.

  The refractory layer 117 covers part or all of the outer surfaces of the light transmission tube 111 and the cooling tube (outer tube 115). As the refractory constituting the refractory layer 117, a refractory used in a normal steelmaking process or the like can be used. For example, a magnesia spinel castable material or the like can be used. The refractory layer 117 can be formed, for example, as follows. First, a ceramic slurry is prepared by mixing ceramic powder and water. Next, after a member composed of a light transmission tube 111, an inner tube 113, and an outer tube 115 is installed at the center of the mold, the ceramic slurry prepared as described above is poured and cast molding is performed. Furthermore, the refractory layer 117 can be formed by baking after demolding and degreasing.

(Definition of terms)
Here, the definition of terms used in the following description will be described with reference to FIG. FIG. 5 is an explanatory diagram for explaining the definition of terms in this specification.

  As shown in FIG. 5, the cross-sectional area Si means the cross-sectional area of the horizontal cross section of the supply side flow path of the cooling medium formed by the outer surface of the light transmission tube 111 and the inner surface of the inner tube 113. Means the cross-sectional area of the horizontal cross section of the discharge side flow path of the cooling medium formed by the outer surface of the inner tube 113 and the inner surface of the outer tube 115. Further, the surface area Sini means the surface area of the outer surface of the light transmission tube 111, and the surface area Sfin means the surface area of the outer surface of the light transmission tube 111 (cooling) when a cooling fin described later is provided on the outer surface of the light transmission tube 111. Including the surface area of the fin). Further, the refractory outer diameter r1 means a horizontal distance from the inner surface of the light transmission tube 111 to the outer surface of the refractory layer 117, and the refractory inner diameter r2 is from the inner surface of the light transmission tube 111 (light transmission). It means the distance in the horizontal direction to the inner surface of the refractory layer 117 (at the part where the tube 111 and the cooling tube are formed).

In the following description, the heat transfer coefficient hi means the heat transfer coefficient in the supply side flow path of the cooling medium, and the heat transfer coefficient ho means the heat transfer coefficient in the discharge side flow path of the cooling medium. Further, in the present embodiment, the heat transfer coefficient h is the radius of the inner or outer surface of the tube, r is the radius, Q is the heat passage amount, Tw is the surface temperature of the tube, and Tg is the temperature of the cooling gas. It shall be represented by the following formula.
h = Q / 2πrl · | Tw−Tg |

  Further, the heat transfer coefficient determined in this way can be obtained, for example, by measuring the tube surface temperature and the cooling gas temperature with a thermocouple, and measuring the amount of heat passing in the radial direction of the tube with a heat flux meter. Can do.

Specifically, in the present embodiment, first, regarding the heat transfer coefficient hi, in the region of the length l of the tube 111, the radius of the tube outer surface is r, the temperature of the tube outer surface is Tw, and the temperature of the cooling gas in contact is Tg. When the amount of heat passage measured on the inner surface of the tube 111 becomes a steady state with Q, the heat transfer coefficient hi is expressed by the following equation.
hi = Q / 2πrl · (Tg−Tw)

As for the heat transfer coefficient ho, in the region of the length l of the tube 115, the radius of the inner surface of the tube is r, the temperature of the inner surface of the tube is Tw ′, the temperature of the cooling gas in contact is Tg ′, and the outer surface of the tube 115 When the measured amount of heat passage is Q ′, the heat transfer coefficient ho is expressed by the following equation.
ho = Q ′ / 2πrl · (Tw′−Tg ′)

  Next, the configuration and the like of the molten metal measuring apparatus according to the second to sixth embodiments of the present invention will be described using the parameters defined as described above. The measuring apparatus for molten metal according to the second to sixth embodiments of the present invention includes the cooling pipe provided outside the light transmission pipe 111 as a cooling means, and thus the first embodiment described above. However, it is different from the first embodiment in that it has a configuration for increasing the cooling efficiency of the reflecting surface inside the light-transmitting tube and reducing the cooling efficiency of the outer surface of the refractory layer. . With such a configuration, in the measurement apparatus for molten metal according to the second to sixth embodiments of the present invention, it is possible to suppress a decrease in reflectance on the reflection surface due to heat reception from the molten metal, and to the outer surface of the cylindrical member. Can suppress the growth of bullion. And it becomes possible to improve the operativity of the measuring apparatus for molten metals by this.

  The configuration of the molten metal measuring apparatus according to the second to sixth embodiments of the present invention is different from that of the first embodiment because a part of the configuration inside the cylindrical member is different from that of the first embodiment. The description of the parts common to the form may be omitted.

[Second Embodiment]
First, the configuration of the cylindrical member 200 according to the second embodiment of the present invention will be described in detail with reference to FIG. In addition, FIG. 6 is explanatory drawing which shows the structure of the cylindrical member 200 which concerns on this embodiment.

  As shown in FIG. 6, the cylindrical member 200 mainly includes a light transmission tube 211, a cooling tube formed by the inner tube 213 and the outer tube 215, a refractory layer 217, and cooling fins 219. . That is, the cylindrical member 200 has a triple tube structure including a light transmission tube 211, an inner tube 213, and an outer tube 215.

  The light transmission tube 211 has a reflection surface 210 a on the inner surface side, and transmits light emitted from the molten steel M. In the light transmission tube 211, the end portion on the molten steel M side with respect to the transmission direction of light emission from the molten steel M is a distance from the end portion on the molten steel M side with respect to the transmission direction of light emission from the molten steel M in the tubular member 200. The point of being separated by H is the same as in the case of the first embodiment. Therefore, the reflection surface 210a is also located at the end on the molten steel M side with respect to the transmission direction of light emission from the molten steel M, and from the end on the molten steel M side with respect to the transmission direction of light emission from the molten steel M in the tubular member 200. They are separated by H.

  The cooling pipe according to the present embodiment is an example of a cooling unit that cools at least the reflection surface 210a on the inner surface of the light transmission pipe 211, and is formed by the inner pipe 213 and the outer pipe 215 as described above.

  The inner tube 213 is coaxially provided outside the light transmission tube 211, and the outer tube 215 is coaxially provided outside the inner tube 213. In addition, the inner tube 213 and the outer tube 215 communicate with each other at the end on the molten steel M side in the transmission direction of the measurement light L (in this embodiment, the lower end in the vertical direction). Then, the cooling medium is supplied from the end on the measuring instrument 11 side (in this embodiment, the upper end in the vertical direction) with respect to the transmission direction of the measuring light L of the inner tube 213, and the end of the outer pipe 215 on the measuring instrument 11 side. The cooling medium is discharged from the section. As described above, the cooling medium flows in the cooling pipe, so that the reflection surface 210a on the inner surface of the light transmission pipe 211 is mainly cooled. The type of the cooling medium used in this embodiment and the materials of the light transmission tube 211, the inner tube 213, and the outer tube 215 are the same as those in the first embodiment.

  The refractory layer 217 covers part or all of the outer surfaces of the light transmission tube 211 and the cooling tube (outer tube 215). The kind and forming method of the refractory constituting the refractory layer 217 are the same as in the case of the first embodiment.

  The cooling fins 219 are provided in the cooling medium supply-side flow path 210 b formed by the outer surface of the light transmission tube 211 and the inner surface of the inner tube 213. Specifically, in the present embodiment, a plurality of cooling fins 219 are provided on the outer surface of the light transmission tube 211 along the longitudinal direction thereof. On the other hand, cooling fins are not provided in the cooling medium discharge-side flow path 210 c formed by the outer surface of the inner tube 213 and the inner surface of the outer tube 215.

  As described above, in the molten metal measuring apparatus according to the present embodiment, the cooling fin 219 is provided on the outer surface of the light transmission tube 211 having the reflection surface 210a for light emission from the molten steel M, whereby the cooling medium discharge side flow path is provided. Compared to 210c, the heat transfer rate of the supply-side flow path 210b of the cooling medium can be increased. Therefore, according to the molten metal measuring apparatus according to the present embodiment, the cooling efficiency of the light transmission tube 211 can be increased and the cooling efficiency of the refractory layer 217 can be decreased. In addition, it is possible to suppress a decrease in the reflectance of the refractory layer and to suppress the growth of the metal on the outer surface of the refractory layer 217 (that is, the outer surface of the cylindrical member 200).

  Here, with reference to FIG. 7, the effect of suppressing the decrease in reflectance and the effect of suppressing the growth of bullion by providing the cooling fins 219 will be described. 7 shows the increase rate Sfin / Sini of the surface area of the outer surface of the light transmission tube 211 due to the provision of the cooling fins 219, the heat transfer coefficient ho in the discharge side flow path 210c, and the heat transfer rate in the supply side flow path 210b. It is a graph which shows an example of the relationship with heat transfer coefficient ratio ho / hfin with hfin.

In FIG. 7, the inner diameter of the light transmission tube 211 having the reflecting surface 210a is 8 mm, the outer diameter is 12 mm, the inner tube 213 is 16 mm, the outer diameter is 20 mm, the outer tube 215 is 24 mm, the cooling medium In the example, the flow rate of (cooling gas) is 1.0 Nm ³ / min, and Sfin is increased while Sini is constant, that is, the surface area of the cooling fin 219 is increased.

  As shown in FIG. 7, when the surface area increase rate Sfin / Sini was increased, the heat transfer coefficient ratio ho / hfin was significantly reduced. From this, it can be seen that increasing the surface area of the cooling fins 219 increases the cooling efficiency in the supply-side flow path 210b and increases the effect of reducing the cooling efficiency in the discharge-side flow path 210c.

[Third Embodiment]
Next, the configuration of the tubular member 300 according to the third embodiment of the present invention will be described in detail with reference to FIG. In addition, FIG. 8 is explanatory drawing which shows the structure of the cylindrical member 300 which concerns on this embodiment.

  As shown in FIG. 8, the cylindrical member 300 mainly includes a light transmission tube 311, a cooling tube formed by an inner tube 313 and an outer tube 315, and a refractory layer 317. That is, the cylindrical member 300 has a triple tube structure including a light transmission tube 311, an inner tube 313, and an outer tube 315.

  The light transmission tube 311 has a reflection surface 310a on the inner surface side, and transmits light emitted from the molten steel M. In the light transmission tube 311, the end on the molten steel M side with respect to the transmission direction of light emission from the molten steel M is distanced from the end on the molten steel M side with respect to the transmission direction of light emission from the molten steel M in the tubular member 300. The point of being separated by H is the same as in the case of the first embodiment. Accordingly, the reflecting surface 310a is also located at the end on the molten steel M side with respect to the transmission direction of light emission from the molten steel M, and from the end on the molten steel M side with respect to the transmission direction of light emission from the molten steel M in the tubular member 300. They are separated by H.

  The cooling pipe according to the present embodiment is an example of a cooling unit that cools at least the reflection surface 310a on the inner surface of the light transmission pipe 311 and is formed by the inner pipe 313 and the outer pipe 315 as described above.

  The inner tube 313 is provided coaxially outside the light transmission tube 311, and the outer tube 315 is provided coaxially outside the inner tube 313. In addition, the inner tube 313 and the outer tube 315 communicate with each other at the end portion on the molten steel M side in the transmission direction of the measurement light L (in this embodiment, the lower end portion in the vertical direction). Then, the cooling medium is supplied from the end on the measuring instrument 11 side (in this embodiment, the upper end in the vertical direction) with respect to the transmission direction of the measuring light L of the inner tube 313, and the end of the outer pipe 315 on the measuring instrument 11 side. The cooling medium is discharged from the section. As described above, the cooling medium flows in the cooling pipe, so that the reflection surface 310a on the inner surface of the light transmission pipe 311 is mainly cooled. In addition, the kind of the cooling medium used in this embodiment and the material of the light transmission tube 311, the inner tube 313, and the outer tube 315 are the same as those in the first embodiment.

  The refractory layer 317 covers part or all of the outer surfaces of the light transmission tube 311 and the cooling tube (outer tube 315). The type and forming method of the refractory constituting the refractory layer 317 are the same as in the case of the first embodiment.

  In the present embodiment, the cross-sectional area So of the cooling medium discharge side flow path 310 c formed by the outer surface of the inner tube 313 and the inner surface of the outer tube 315 is determined by the outer surface of the light transmission tube 311 and the inner surface of the inner tube 313. The cooling pipe is provided so as to be larger than the cross-sectional area Si of the cooling medium supply side passage 310b to be formed.

  Thus, in the molten metal measuring device according to the present embodiment, the discharge-side flow path of the cooling medium is set by making the cross-sectional area So of the discharge-side flow path 310c larger than the cross-sectional area Si of the supply-side flow path 310b. The heat transfer coefficient of 310c can be suppressed. Therefore, according to the molten metal measuring apparatus according to the present embodiment, the cooling efficiency of the refractory layer 317 can be reduced while maintaining the cooling efficiency of the light transmission tube 311 in a high state. It is possible to suppress a decrease in reflectance on the reflective surface 310a due to heat reception, and to suppress the growth of a metal on the outer surface of the refractory layer 317 (that is, the outer surface of the cylindrical member 300).

  Here, with reference to FIG. 9, a description will be given of an effect of suppressing the decrease in reflectance and an effect of suppressing the growth of bullion by making the sectional area So of the discharge-side channel 310c larger than the sectional area Si of the supply-side channel 310b. Note that FIG. 9 shows the flow path cross-sectional area ratio So / Si between the cross-sectional area So of the discharge-side flow path 310c and the cross-sectional area Si of the supply-side flow path 310b, the heat transfer coefficient ho and the supply side in the discharge-side flow path 310c. It is a graph which shows an example of the relationship between the heat transfer rate hi and the heat transfer rate ratio ho / hi in the flow path 310b.

9, the inner diameter of the light transmission tube 311 having the reflecting surface 310a is 8 mm, the outer diameter is 12 mm, the inner tube 313 is 16 mm, the outer diameter is 20 mm, and the flow rate of the cooling medium (cooling gas) is 1. An example is shown in which the inner diameter of the outer tube 315 is changed to 0 Nm ³ / min.

  As shown in FIG. 9, when the flow path cross-sectional area ratio So / Si increased, the heat transfer coefficient ratio ho / hi significantly decreased. Therefore, when the cross-sectional area So of the discharge-side flow path 310c is made larger than the cross-sectional area Si of the supply-side flow path 310b, the cooling efficiency in the supply-side flow path 310b can be maintained high, and the cooling in the discharge-side flow path 310c. It turns out that the effect which reduces efficiency increases.

[Fourth Embodiment]
Next, the configuration of the tubular member 400 according to the fourth embodiment of the present invention will be described in detail with reference to FIG. In addition, FIG. 10 is explanatory drawing which shows the structure of the cylindrical member 400 which concerns on this embodiment.

  As shown in FIG. 10, the cylindrical member 400 mainly includes a light transmission tube 411, a cooling tube formed by an inner tube 413 and an outer tube 415, and a refractory layer 417. That is, the cylindrical member 400 has a triple tube structure including a light transmission tube 411, an inner tube 413, and an outer tube 415.

  The light transmission tube 411 has a reflection surface 410a on the inner surface side, and transmits light emitted from the molten steel M. In the light transmission tube 411, the end of the molten steel M side with respect to the transmission direction of light emission from the molten steel M is distanced from the end of the molten steel M side with respect to the transmission direction of light emission from the molten steel M in the tubular member 400. The point of being separated by H is the same as in the case of the first embodiment. Therefore, the reflecting surface 410a also has an end portion on the molten steel M side with respect to the transmission direction of light emission from the molten steel M, and a distance from the end portion on the molten steel M side with respect to the transmission direction of light emission from the molten steel M in the tubular member 400. They are separated by H.

  The cooling pipe according to the present embodiment is an example of a cooling unit that cools at least the reflection surface 410a on the inner surface of the light transmission pipe 411, and is formed by the inner pipe 413 and the outer pipe 415 as described above.

  The inner tube 413 is coaxially provided outside the light transmission tube 411, and the outer tube 415 is coaxially provided outside the inner tube 413. In addition, the inner tube 413 and the outer tube 415 communicate with each other at the end portion on the molten steel M side in the transmission direction of the measurement light L (in this embodiment, the lower end portion in the vertical direction). Then, the cooling medium is supplied from the end on the measuring instrument 11 side (in this embodiment, the upper end in the vertical direction) with respect to the transmission direction of the measuring light L of the inner tube 413, and the end of the outer pipe 415 on the measuring instrument 11 side. The cooling medium is discharged from the section. As described above, the cooling medium flows through the cooling pipe, whereby the reflecting surface 410a on the inner surface of the light transmission pipe 411 is mainly cooled. In addition, the kind of the cooling medium used in this embodiment and the material of the light transmission tube 411, the inner tube 413, and the outer tube 415 are the same as those in the first embodiment.

  The refractory layer 417 covers part or all of the outer surfaces of the light transmission tube 411 and the cooling tube (outer tube 415). The kind and forming method of the refractory constituting the refractory layer 417 are the same as in the case of the first embodiment.

  In the present embodiment, the outer tube 415 has a tapered shape in which the diameter on the measurement unit 11 side is larger than the diameter on the molten steel M side with respect to the transmission direction of light emission from the molten steel M, and is cylindrical. The cross-sectional area of the discharge side flow path 410c of the cooling medium formed by the outer surface of the inner tube 413 and the inner surface of the outer tube 415 at the end on the measurement unit 11 side with respect to the transmission direction of light emission from the molten steel M of the member 400. The cooling pipe is provided so that So is larger than the cross-sectional area Si of the cooling medium supply side channel 410b formed by the outer surface of the light transmission tube 411 and the inner surface of the inner tube 413. In FIG. 10, the shape of the refractory layer 417 is drawn in a tapered shape in accordance with the shape of the outer tube 415, but the shape of the refractory layer 417 is not necessarily a tapered type.

  As described above, in the molten metal measuring apparatus according to this embodiment, the outer pipe 415 is tapered so that the discharge-side flow path 410c is disconnected as in the case of the third embodiment described above. The area So can be partially made larger than the cross-sectional area Si of the supply-side flow path 410b, whereby the heat transfer rate of the discharge-side flow path 410c of the cooling medium can be suppressed. Therefore, according to the molten metal measuring apparatus according to the present embodiment, the cooling efficiency of the refractory layer 417 can be lowered while maintaining the cooling efficiency of the light transmission tube 411 in a high state. While the reflectance fall in the reflective surface 410a by heat reception can be suppressed, the growth of the metal on the outer surface of the refractory layer 417 (that is, the outer surface of the cylindrical member 400) can be suppressed.

[Fifth Embodiment]
Next, the configuration of the cylindrical member 500 according to the fifth embodiment of the present invention will be described in detail with reference to FIG. In addition, FIG. 11 is explanatory drawing which shows the structure of the cylindrical member 500 which concerns on this embodiment.

  As shown in FIG. 11, the cylindrical member 500 mainly includes a light transmission tube 511, a cooling tube formed by an inner tube 513 and an outer tube 515, and a refractory layer 517. That is, the cylindrical member 500 has a triple tube structure including a light transmission tube 511, an inner tube 513, and an outer tube 515.

  The light transmission tube 511 has a reflection surface 510 a on the inner surface side, and transmits light emitted from the molten steel M. In the light transmission tube 511, the end portion on the molten steel M side with respect to the transmission direction of light emission from the molten steel M is a distance from the end portion on the molten steel M side with respect to the transmission direction of light emission from the molten steel M in the tubular member 500. The point of being separated by H is the same as in the case of the first embodiment. Therefore, the reflecting surface 510a is also located at the end on the molten steel M side with respect to the transmission direction of light emission from the molten steel M, and from the end on the molten steel M side with respect to the transmission direction of light emission from the molten steel M in the tubular member 500. They are separated by H.

  The cooling tube according to the present embodiment is an example of a cooling unit that cools at least the reflection surface 510a on the inner surface of the light transmission tube 511, and is formed by the inner tube 513 and the outer tube 515 as described above.

  The inner tube 513 is coaxially provided outside the light transmission tube 511, and the outer tube 515 is coaxially provided outside the inner tube 513. In addition, the inner tube 513 and the outer tube 515 communicate with each other at the end (on the lower end in the vertical direction) on the molten steel M side with respect to the transmission direction of the measurement light L. Then, the cooling medium is supplied from the end on the measuring instrument 11 side (in this embodiment, the upper end in the vertical direction) with respect to the transmission direction of the measuring light L of the inner tube 513, and the end of the outer pipe 515 on the measuring instrument 11 side. The cooling medium is discharged from the section. As described above, the cooling medium flows in the cooling pipe, so that the reflection surface 510a on the inner surface of the light transmission pipe 511 is mainly cooled. In addition, the kind of the cooling medium used in this embodiment and the material of the light transmission tube 511, the inner tube 513, and the outer tube 515 are the same as in the case of the first embodiment.

  The refractory layer 517 covers part or all of the outer surfaces of the light transmission tube 511 and the cooling tube (outer tube 515). The kind of the refractory constituting the refractory layer 517 is the same as in the case of the first embodiment.

  In the present embodiment, the physical properties of the refractory are optimized according to the desired inner surface temperature and outer surface temperature of the refractory layer 517. More specifically, for example, the thermal conductivity λ of the refractory layer 517 and the outer diameter r1 and inner diameter r2 of the refractory layer 517 are determined according to the desired inner surface temperature and outer surface temperature of the refractory layer 517.

  Here, as a desired inner surface temperature of the refractory layer 517, for example, the material (for example, SUS) of the light transmission tube 511, the inner tube 513, and the outer tube 515 inside the refractory layer 517 is protected from deterioration due to heat. (In particular, the mirror surface state of the reflecting surface 510a on the inner surface side of the light transmission tube 511 can be maintained). Further, examples of the desired outer surface temperature of the refractory layer 517 include a temperature that can suppress the growth of metal on the outer surface of the refractory layer 517.

  Further, the thermal conductivity λ of the refractory layer 517 can be adjusted by controlling the porosity in the refractory layer 517. Thus, as a method for controlling the porosity, for example, there are the following two methods.

  First, a method of reducing the thermal conductivity of the refractory layer 517 by adding bubbles to a ceramic slurry prepared by mixing ceramic powder and water and stirring to form bubbles in the slurry. It is. The foaming agent in this case is not particularly limited as long as it can form bubbles, and includes a foaming agent and a surfactant. More specifically, examples of the foaming agent used in this embodiment include protein foaming agents, egg whites, surfactants such as alkylbenzene sulfonates and higher alkyl amino acids, and the like. In the case of this first example, the thermal conductivity of the refractory layer 517 can be reduced by increasing the amount of foaming agent added or by selecting a foaming agent that can produce a large amount of bubbles. it can.

  Second, by mixing a particulate organic material into the ceramic slurry, the organic material is decomposed during firing to form bubbles, thereby increasing the thermal conductivity of the refractory layer 517. It is a method of reducing. Examples of the granular organic material in this case include expanded polystyrene and plastic beads. In the case of the second example, the thermal conductivity of the refractory layer 517 can be reduced by increasing the amount of the organic substance added.

The thermal conductivity λ of the refractory layer thus adjusted can be obtained, for example, by measuring the surface temperature of the refractory with a thermocouple and measuring the amount of heat passing with a heat flux meter. Specifically, in this embodiment, the heat conductivity λ of the refractory layer is such that the inner temperature is T1 and the outer temperature is T2 in the region of the refractory layer having an inner diameter r1, an outer diameter r2, and a length l. If the measured heat passage amount is Q, the following formula is used.
λ = Q · ln (r2 / r1) / (2πl · (T1-T2))

Moreover, the porosity in this embodiment means the ratio of the pores (open pores and closed pores) volume to the external volume of the refractory construction part. The porosity P can be obtained from the following formula by measuring the true specific gravity Dt and the bulk specific gravity Db based on JIS R2205 (“Measurement Method of Apparent Porosity, Water Absorption, and Specific Gravity of Refractory Bricks”).
P = 1−Db / Dt

  As described above, in the molten metal measuring apparatus according to this embodiment, by optimizing the physical properties of the refractory layer 517 and the shape and size of the refractory layer 517, the light transmission tube 511, the inner tube 513, and the outer The temperature rise of the tube 515 can be suppressed. Therefore, according to the measuring apparatus for molten metal according to the present embodiment, the cooling efficiency of the light transmission tube 511 can be prevented from being lowered, and the cooling efficiency of the refractory layer 517 can be maintained in a low state. As a result, it is possible to suppress a decrease in the reflectance on the reflection surface 510a due to the above, and to suppress the growth of the metal on the outer surface of the refractory layer 517 (that is, the outer surface of the cylindrical member 500).

Here, with reference to FIG. 12, the effect of suppressing the decrease in reflectance and the effect of suppressing the growth of bullion by optimizing the physical properties of the refractory layer 517 and the shape and size of the refractory layer 517 will be described. FIG. 12 shows the relationship between λ / ln (r1 / r2) (W / m · k) used as an index of the heat transfer coefficient in the refractory layer 517 and the inner surface temperature (° C.) of the refractory layer 517. It is a graph which shows an example. The reason why λ / ln (r1 / r2) is used as an index of the heat transfer coefficient in the refractory layer 517 is as follows. That is, if the temperature of the inner surface of the refractory layer 517 is T2, the temperature of the outer surface is T1, and the amount of heat passing through the refractory layer 517 is Q, the relationship of the following formula (1) is established for the region of length l. According to this equation (1), since the temperature T2 of the inner surface of the refractory layer 517 is determined by λ / ln (r1 / r2), λ / ln (r1 / r2) is an index of the heat transfer coefficient in the refractory layer 517. It was.
T2 = T1-Q / (2πl · λ / ln (r1 / r2)) (1)

  In FIG. 12, the outer diameter of the inner tube 513 is 20 mm, the inner diameter of the outer tube 515 is 24 mm, the outer diameter is 28 mm (constant), the inner surface temperature of the outer tube 515 is 25 ° C., and the outer surface temperature of the refractory layer 517 Is 1600 ° C., and the heat conductivity λ of the refractory layer 517 and the inner diameter r2 of the refractory layer 517 are changed.

  As shown in FIG. 12, when the heat transfer coefficient λ / ln (r1 / r2) of the refractory layer 517 increases, the inner surface temperature of the refractory layer 517 also increases. Therefore, when it is desired to lower the temperature of the inner surface of the refractory layer 517 and lower the temperature of the light transmission tube 511 and the cooling tube, the heat transfer coefficient of the refractory layer 517 is lowered (for example, the refractory layer 517 It is understood that it is necessary to reduce the thermal conductivity λ by increasing the porosity. In this case, the cooling efficiency of the light transmission tube 511 can be prevented from being lowered, and the cooling efficiency of the refractory layer 517 can be maintained in a low state.

[Sixth Embodiment]
Next, the configuration of the cylindrical member 600 according to the sixth embodiment of the present invention will be described in detail with reference to FIG. In addition, FIG. 13 is explanatory drawing which shows the structure of the cylindrical member 600 which concerns on this embodiment.

  As shown in FIG. 13, the cylindrical member 600 mainly includes a light transmission tube 611, a cooling tube formed by an inner tube 613 and an outer tube 615, and a refractory layer 617. That is, the cylindrical member 600 has a triple tube structure including a light transmission tube 611, an inner tube 613, and an outer tube 615.

  The light transmission tube 611 has a reflection surface 610a on the inner surface side, and transmits light emitted from the molten steel M. In the light transmission tube 611, the end on the molten steel M side with respect to the transmission direction of light emission from the molten steel M is distanced from the end on the molten steel M side with respect to the transmission direction of light emission from the molten steel M in the tubular member 600. The point of being separated by H is the same as in the case of the first embodiment. Therefore, the reflecting surface 610a also has an end on the molten steel M side with respect to the transmission direction of light emission from the molten steel M, and a distance from the end on the molten steel M side with respect to the transmission direction of light emission from the molten steel M in the tubular member 600. They are separated by H.

  The cooling tube according to the present embodiment is an example of a cooling unit that cools at least the reflection surface 610a on the inner surface of the light transmission tube 611, and is formed by the inner tube 613 and the outer tube 615 as described above.

  The inner tube 613 is coaxially provided outside the light transmission tube 611, and the outer tube 615 is coaxially provided outside the inner tube 613. In addition, the inner tube 613 and the outer tube 615 communicate with each other at the end portion on the molten steel M side in the transmission direction of the measurement light L (in this embodiment, the lower end portion in the vertical direction). Then, the cooling medium is supplied from the end on the measuring instrument 11 side (in this embodiment, the upper end in the vertical direction) with respect to the transmission direction of the measuring light L of the inner pipe 613, and the end of the outer pipe 615 on the measuring instrument 11 side. The cooling medium is discharged from the section. As described above, the cooling medium flows in the cooling pipe, so that the reflection surface 610a on the inner surface of the light transmission pipe 611 is mainly cooled. In addition, the kind of the cooling medium used in this embodiment and the material of the light transmission tube 611, the inner tube 613, and the outer tube 615 are the same as in the case of the first embodiment.

  The refractory layer 617 covers part or all of the outer surfaces of the light transmission tube 611 and the cooling tube (outer tube 615). The kind of the refractory constituting the refractory layer 617 is the same as in the first embodiment.

  In the present embodiment, the refractory layer 617 has a void inside. In the example shown in FIG. 13, the refractory layer 617 has a slit 618 as the gap. Such a slit 618 can be formed as follows, for example. That is, the organic material is decomposed when the refractory layer 617 is fired by applying the refractory layer 617 after winding a linear or net-like organic material around the outer tube 615. A slit 618 can be formed in a portion where the system material is wound. Examples of the organic material in this case include plastic and paper.

  Further, as a modification of the present embodiment, the ceramic member is formed by forming a refractory layer such as castable after winding a ceramic felt around the outer tube 615 in a portion immersed in the molten steel M of the cylindrical member 600. By utilizing the fact that the felt includes a void, a void can be formed inside the refractory layer 617.

  As described above, in the molten metal measuring apparatus according to this embodiment, the porosity of the refractory layer 517 is increased in the fifth embodiment by providing a gap such as the slit 618 inside the refractory layer 617. The heat transfer coefficient of the refractory layer 617 can be reduced for the same reason as described above. In the case of the above modification, the thermal conductivity of the refractory layer 617 can be lowered by increasing the amount of ceramic felt wound around the outer tube 615. Therefore, according to the molten metal measuring apparatus according to the present embodiment, the cooling efficiency of the light transmission tube 611 can be prevented from being lowered, and the cooling efficiency of the refractory layer 617 can be maintained in a low state. As a result, it is possible to suppress a decrease in reflectance on the reflection surface 610a due to the above, and it is possible to suppress the growth of metal on the outer surface of the refractory layer 617 (that is, the outer surface of the cylindrical member 600).

  Here, with reference to FIG. 14, a description will be given of the effect of suppressing the decrease in reflectance and the effect of suppressing the growth of bullion by providing a void inside the refractory layer 617. 14 shows the heat transfer coefficient ratio between the porosity Φ of the refractory layer 617, the heat transfer coefficient Kφ when the refractory layer 617 is provided with a gap, and the heat transfer coefficient K0 when no vacant is provided. It is a graph which shows an example of a relationship with Kphi / K0.

FIG. 14 shows the heat when the refractory layer 617 has an inner diameter r2 = 28 mm and an outer diameter r1 = 128 mm, and there is a void having a porosity φ in a region in the refractory layer 617 having a diameter of 28 mm to 78 mm. An example in which the transfer rate Kφ is compared with the heat transfer rate K0 when φ = 0 is shown. The calculation was performed assuming that the heat transfer coefficient is (1−φ) times in a region having voids. Note that the porosity φ in the present embodiment means the ratio of the volume of the void portion to the external volume of this region when the void is provided in the region where the diameter is r1 to r2 in the refractory layer 617. . This void ratio φ can be obtained by the following equation, where V is the outer volume of the region where the void is provided, and Vs is the volume of the void portion.
φ = Vs / V

  As shown in FIG. 14, as the porosity φ increased, the heat transfer coefficient ratio Kφ / K0 decreased. From this, it can be seen that when the porosity φ of the refractory layer 617 is increased, the effect of lowering the heat transfer coefficient due to the provision of the voids is increased.

  In addition, the reflectance in the reflective surface by the heat reception from a molten metal is employ | adopted by employ | adopting at least any 1 type among the structures of the measuring apparatus for molten metals which concerns on the 2nd-6th embodiment of this invention demonstrated above. In addition, it is possible to obtain the effect that the lowering of the metal can be suppressed and the growth of the metal on the outer surface of the cylindrical member can be suppressed. However, the above-described effect can be further enhanced by combining any two or more of the configurations of the molten metal measuring apparatus according to the second to sixth embodiments of the present invention described above. In particular, the molten metal measuring device that combines the second embodiment, the third embodiment liquid, and the fifth embodiment described above can suppress a decrease in reflectance on the reflecting surface due to heat reception from the molten metal, and The effect that the growth of the metal on the outer surface of the cylindrical member can be suppressed is most excellent.

  Next, the present invention will be described more specifically using examples and comparative examples.

Example 1
This example is an example of analyzing the carbon concentration in molten steel as a measurement example of molten metal. Specifically, the carbon concentration in the molten steel melted in the induction melting furnace was analyzed by laser-induced fluorescence analysis using the tubular member according to the present invention described above.

  In this example, a Q switch pulse Nd: YAG laser was used as an ablation laser used for laser-induced fluorescence analysis, and a titanium sapphire laser was used as a selective excitation laser. The wavelength of the selective excitation laser was 247.85 nm, and the amount of laser-induced fluorescence having a wavelength of 193.09 nm was measured with a light amount detector. A photomultiplier tube was used as the light amount detector. Further, laser-induced fluorescence generated on the surface of the molten steel was reflected by a mirror provided above the cylindrical member and introduced into the light amount detector.

  Here, the cylindrical member 1100 used in Example 1 is shown in FIG. The cylindrical member 1100 includes a light transmission tube 1111, an inner tube 1113, an outer tube 1115, and a refractory layer 1117 formed of a stainless steel (SUS316) tube. The light transmission tube 1111 had an outer diameter of 13.8 mm and a thickness of 1.65 mm, and a reflection surface was formed on the inner surface side by electrolytic polishing. Further, as the inner tube 1113, a stainless steel tube having an outer diameter of 42.7 mm and a thickness of 1.65 mm was used, and as the outer tube 1115, a stainless steel tube having an outer diameter of 76.3 mm and a thickness of 3.0 mm was used. . A magnesia spinel castable material was used as the refractory layer 1117, and a protein foaming agent was used as a foaming agent when the refractory layer 1117 was formed. The refractory layer 1117 had a thickness of 150 mm and a porosity of 70%. Further, the distance from the lower end of the refractory layer 1117 to the lower end of the light transmission tube 1111 was set to 50.0 mm. At this time, the ratio So / Si of the cross-sectional area Si of the cooling gas supply-side flow path 1110b and the cross-sectional area So of the discharge-side flow path 1110c is 2.3. Further, the index λ / ln (r1 / r2) of the heat transfer coefficient of the refractory layer 1117 is 0.3. Further, the thermal conductivity of the magnesia spinel castable material used as the refractory in this example was 84% MgO, 17.5% porosity, and 2.4 W / m · K (AGC ceramics HP) at 1000 ° C. .

As analysis conditions, while introducing argon gas into the light transmission tube 1111 at 2.0 NL / min so that molten steel does not flow from the opening of the tubular member 1100, the tip of the tubular member 1100 for measurement is used. Immersion to a depth of 50 mm. At this time, the tip of the cylindrical member 1100 was located below the slag on the surface of the molten steel. In addition, air was introduced as a cooling gas at 7.5 Nm ³ / min. The molten steel temperature was 1650 ° C.

  FIG. 17 shows the results of analyzing the carbon concentration in the molten steel under such conditions. The vertical axis in FIG. 17 indicates the laser-induced fluorescence light amount (mV), and the horizontal axis indicates the carbon concentration (ppm). In addition, the analysis result according to this example is indicated by “♦”. The carbon concentration in the molten steel was measured by a combustion infrared absorption method.

  As shown in FIG. 17, the laser-induced fluorescence light quantity (mV) and the carbon concentration (ppm) show a substantially linear correlation. By using the cylindrical member 1100 of this example, the laser-induced fluorescence analysis method is used. It was confirmed that analysis with high accuracy of carbon concentration is possible.

  The temperature on the discharge side of the cooling gas during the analysis of the carbon concentration was about 520 ° C., and the cylindrical member 1100 was not deformed and could be used for the analysis without any problem. In addition, after the analysis was completed, no metal was attached to the outer surface of the cylindrical member 1100.

(Example 2)
Also in the present example, as in Example 1, the carbon concentration in the molten steel was analyzed as a measurement example of the molten metal.

  A cylindrical member 1200 used in this example is shown in FIG. The cylindrical member 1200 includes a light transmission tube 1211, an inner tube 1213, an outer tube 1215, and a refractory layer 1217 formed of a stainless steel (SUS304) tube. The light-transmitting tube 1211 has an outer diameter of 13.8 mm and a thickness of 1.65 mm, a reflective surface is formed by electrolytic polishing finishing on the inner surface side, and has a height of 15.0 mm and a thickness of 1.0 mm as cooling fins on the outer surface. Twelve stainless steel plates were attached. In addition, a refractory layer 1217 was constructed after winding a polypropylene wire having a wire diameter of 2.0 mm around the outer tube 1215 at a pitch of 3.0 mm. Other design conditions are the same as those in the first embodiment. At this time, the surface area increase rate Sfin / Sini due to the cooling fin is 8.2, and the ratio So / Si of the cross-sectional area Si of the cooling gas supply-side flow path 1210b to the cross-sectional area So of the discharge-side flow path 1210c is 2. 3 Further, the index λ / ln (r1 / r2) of the heat transfer coefficient of the refractory layer 1217 is 0.25.

In order to prevent molten steel from flowing from the opening of the cylindrical member 1200, the argon gas is introduced into the inside of the light transmission tube 1211 at a rate of 2.0 NL / min, and the measurement is immersed from the tip of the cylindrical member 1200 to a depth of 50 mm. did. At this time, the tip of the cylindrical member 1200 was positioned below the slag on the surface of the molten steel. In addition, air was introduced as a cooling gas at 7.5 Nm ³ / min. The molten steel temperature was 1650 ° C.

  As a result of analyzing the carbon concentration in the molten steel by the laser-induced fluorescence analysis under such conditions, the laser-induced fluorescence light amount (mV) and the carbon concentration (ppm) are almost linear as in Example 1. By showing the correlation and using the cylindrical member 1200 of this example, it was confirmed that the analysis with high accuracy of the carbon concentration by the laser induced fluorescence analysis method was possible.

  It should be noted that the temperature on the cooling gas discharge side during the analysis of the carbon concentration was about 270 ° C., and the cylindrical member 1200 was not deformed and could be used for the analysis without any problems. Further, after the analysis was completed, no adhesion of metal to the outer surface of the cylindrical member 1200 was observed.

For reference, as the high temperature strength of stainless steel, both SUS304 and SUS316 have a tensile strength of about 60 kg / mm ² at room temperature. SUS316 is about 600 ° C.

(Comparative Example 1)
As Comparative Example 1, the light transmission tube in Example 1 was made of a pickled finish stainless steel tube. Other design conditions and analysis conditions are the same as in the first embodiment.

  FIG. 17 shows the results of analyzing the carbon concentration in the molten steel under such conditions. The result of analysis according to this comparative example is indicated by “Δ”.

  As shown in FIG. 17, when the cylindrical member of this comparative example is used, the amount of laser-induced fluorescence detected is small compared with the case of using the cylindrical member of Example 1, and the carbon concentration There was no correlation. Therefore, when the cylindrical member in this comparative example was used, it turned out that the precision of the analysis of the carbon concentration in molten steel is low, and cannot be used for the analysis of the carbon concentration in molten steel.

(Example 3)
In this example, molten steel temperature was measured as an example of measuring molten metal. Specifically, the temperature of the molten steel melted in the induction melting furnace was measured by radiation temperature measurement using the tubular member according to the present invention described above.

  In this example, a radiation thermometer was used as a measuring instrument used for radiation temperature measurement. Radiant light from the molten steel surface was reflected by a mirror provided at the upper end of the cylindrical member and introduced into a radiation thermometer. Here, the cylindrical member used in Example 3 is the same as that of Example 1.

As analysis conditions, while introducing argon gas into the light transmission tube 1111 at 2.0 NL / min so that molten steel does not flow from the opening of the tubular member 1100, the tip of the tubular member 1100 for measurement is used. Immersion to a depth of 50 mm. At this time, the tip of the cylindrical member 1100 was located below the slag on the surface of the molten steel. In addition, air was introduced as a cooling gas at 7.5 Nm ³ / min. The result of measuring the temperature of the molten steel under such conditions is shown in FIG.

  As shown in FIG. 18, the measured amount of radiant light and the measurement temperature by the consumable immersion thermocouple, which is a conventional method, show a good correlation. By using the cylindrical member according to the present embodiment, the radiation temperature measurement It was confirmed that continuous and accurate temperature measurement is possible.

  In addition, the discharge side temperature of the cooling gas during measurement of the molten steel temperature was about 520 ° C., and the cylindrical member 1100 was not deformed and could be used for analysis without any problem. In addition, after the analysis was completed, no metal was attached to the outer surface of the cylindrical member 1100.

Example 4
In this example, as in Example 3, the molten steel temperature was measured as an example of measuring molten metal.

  In the present embodiment, the measuring instrument used for radiation temperature measurement and the method of introducing the radiation light are the same as in the third embodiment, and the cylindrical member used is the same as in the second embodiment.

As an analysis condition, while introducing argon gas at 2.0 NL / min into the light transmission tube 1211 so that molten steel does not flow from the opening of the cylindrical member 1200, the tip of the cylindrical member 1200 for measurement is used. Immersion to a depth of 50 mm. At this time, the tip of the cylindrical member 1200 was positioned below the slag on the surface of the molten steel. In addition, air was introduced as a cooling gas at 7.5 Nm ³ / min.

  As a result of the temperature measurement of the molten steel under such conditions, the measured amount of radiant light and the measured temperature by the consumable immersion thermocouple which is the conventional method show a good correlation as in FIG. It was confirmed that by using the cylindrical member according to the above, continuous and accurate temperature measurement by radiation temperature measurement is possible.

  In addition, the discharge side temperature of the cooling gas during the measurement of the molten steel was about 270 ° C., and the cylindrical member 1200 was not deformed and could be used for analysis without any problem. Further, after the analysis was completed, no adhesion of metal to the outer surface of the cylindrical member 1200 was observed.

(Comparative Example 2)
As Comparative Example 2, a light-transmitting tube made of a pickled finish stainless steel tube as in Comparative Example 1 was used. Other design conditions and analysis conditions are the same as in the third embodiment.

  When the cylindrical member of this comparative example is used, since the detected radiation light intensity is small compared to the case of using the cylindrical member of Example 3, the influence of noise cannot be ignored. The variation increased, and no correlation was observed with the temperature measured by a consumable immersion thermocouple. Therefore, it turned out that the cylindrical member in this comparative example cannot be used for temperature measurement of molten steel.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this example. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, in the above-described embodiment, the case of component analysis of molten metal has been described as an example of measurement of molten metal. However, the present invention is a measurement apparatus that performs temperature measurement using light emitted from molten metal. Is also applicable.

  In the above-described embodiment, the case where the cooling means is a cooling pipe having a double pipe structure formed by the inner pipe and the outer pipe has been described. However, the present invention is not limited to this case, and the cooling effect of the reflecting surface is described. As long as the cooling effect of the outer surface of the tubular member is suppressed, any form of cooling means may be used.

It is explanatory drawing which shows the whole structure of the measuring apparatus for molten metals which concerns on the 1st Embodiment of this invention. It is explanatory drawing which shows the structure of the cylindrical member which concerns on the same embodiment. It is explanatory drawing for demonstrating the appropriate value of H / D which concerns on the same embodiment. It is a graph which shows an example of the relationship between SN ratio (dB) and H / D in the embodiment. It is explanatory drawing for demonstrating the definition of the term in this specification. It is explanatory drawing which shows the structure of the cylindrical member which concerns on the 2nd Embodiment of this invention. The heat transfer coefficient between the increase rate Sfin / Sini of the surface area of the outer surface of the light transmission tube and the heat transfer coefficient ho in the discharge side channel and the heat transfer rate hfin in the supply side channel due to the provision of the cooling fins in the embodiment. It is a graph which shows an example of the relationship with ratio ho / hfin. It is explanatory drawing which shows the structure of the cylindrical member which concerns on the 3rd Embodiment of this invention. In the same embodiment, the cross-sectional area ratio So / Si of the cross-sectional area So of the discharge-side flow path and the cross-sectional area Si of the supply-side flow path, the heat transfer coefficient ho in the discharge-side flow path, and the heat transfer in the supply-side flow path. It is a graph which shows an example of the relationship with heat transfer rate ratio ho / hi with rate hi. It is explanatory drawing which shows the structure of the cylindrical member which concerns on the 4th Embodiment of this invention. It is explanatory drawing which shows the structure of the cylindrical member which concerns on the 5th Embodiment of this invention. An example of the relationship between (lambda) / ln (r1 / r2) (W / m * k) used as a parameter | index of the heat transfer coefficient in the refractory layer which concerns on the same embodiment, and the internal surface temperature (degreeC) of a refractory layer is shown. It is a graph. It is explanatory drawing which shows the structure of the cylindrical member which concerns on the 6th Embodiment of this invention. The relationship between the porosity Φ of the refractory layer according to the embodiment and the heat transfer coefficient ratio Kφ / K0 between the heat transfer coefficient Kφ when there is a void in the refractory layer and the heat transfer coefficient K0 when there is no void. It is a graph which shows an example. It is explanatory drawing which shows the structure of the cylindrical member used in Example 1 of this invention. It is explanatory drawing which shows the structure of the cylindrical member used in Example 2 of this invention. It is a graph which shows the result of having analyzed the carbon concentration in the molten steel in Example 1 and a comparative example of the present invention. It is a graph which shows the result of having measured the temperature of the molten steel in Example 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Emission spectroscopy analyzer 11 Measuring device 13 Optical system 15 Mirror 20 Molten steel pan 100, 200, 300, 400, 500, 600 Cylindrical member 110 Cylinder main body 110a, 210a, 310a, 410a, 510a, 610a Reflecting surface 111, 211, 311, 411, 511, 611 Light transmission tube 113, 213, 313, 413, 513, 613 Inner tube 115, 215, 315, 415, 515, 615 Outer tube 117, 217, 317, 417, 517, 617 Refractory layer 210b, 310b, 410b, 510b, 610b Supply side flow path 210c, 310c, 410c, 510c, 610c Discharge side flow path 219 Cooling fin 618 Slit

Claims (10)

A measuring device that performs at least one of component analysis and temperature measurement of the molten metal based on light emission from the molten metal having suspended matter on the surface;
A cylindrical member that transmits light emitted from the molten metal to the measuring device;
With
The tubular member has one end immersed in the molten metal, the other end connected to the measurement portion, and a reflection surface for reflecting the light emission on the inner surface side, the measurement for molten metal apparatus. The reflective surface has an end on the molten metal side with respect to the transmission direction of the light emission on the reflective surface, and is separated from an end on the molten metal side with respect to the transmission direction of the light emission on the cylindrical member. Provided,
The ratio of the distance H between the molten metal side end of the reflecting surface and the molten metal side end of the cylindrical member and the inner diameter D of the cylindrical member is 0 <H / D ≦ 10. The measuring apparatus for molten metal according to claim 1, wherein the measuring apparatus is provided.   The measuring apparatus for molten metal according to claim 1, wherein the cylindrical member includes a cooling unit that cools at least the reflecting surface. The cylindrical member is
A light transmission tube having the reflection surface on the inner surface side and transmitting the light emission;
A cooling pipe formed by an inner pipe provided coaxially outside the light transmission pipe and an outer pipe provided coaxially outside the inner pipe;
A refractory layer covering a part or all of the outer surfaces of the light transmission tube and the cooling tube;
With
The inner tube and the outer tube communicate with each other at one end;
The measuring apparatus for molten metal according to claim 1 or 2, wherein a cooling medium is supplied from the other end of the inner pipe and the cooling medium is discharged from the other end of the outer pipe.   The measurement for molten metal according to claim 4, wherein a cooling fin is provided in a supply-side flow path of the cooling medium formed by an outer surface of the light transmission tube and an inner surface of the inner tube. apparatus.   The cross-sectional area of the discharge side flow path of the cooling medium formed by the outer surface of the inner tube and the inner surface of the outer tube is that of the cooling medium formed by the outer surface of the light transmission tube and the inner surface of the inner tube. The measuring device for molten metal according to claim 4, wherein the measuring device is larger than a cross-sectional area of the supply-side flow path. The outer tube has a tapered shape in which the diameter on the measurement unit side is larger than the diameter on the molten metal side with respect to the transmission direction of the light emission,
The cross-sectional area of the cooling medium discharge-side flow path formed by the outer surface of the inner tube and the inner surface of the outer tube at the end on the measurement unit side with respect to the light transmission direction of the cylindrical member is The molten metal measuring device according to claim 4, wherein the measuring device is larger than a cross-sectional area of a supply-side flow path of the cooling medium formed by an outer surface of the light transmission tube and an inner surface of the inner tube.   The measuring apparatus for molten metal according to claim 4, wherein the thermal conductivity, outer diameter, and inner diameter of the refractory layer are determined according to desired inner surface temperature and outer surface temperature of the refractory layer.   The said refractory layer has a space | gap inside, The measuring apparatus for molten metals of Claim 4 characterized by the above-mentioned. The measuring apparatus for molten metal according to any one of claims 1 to 9, wherein the reflecting surface is made of mirror-finished stainless steel.