Structure of gas inlet hole socket
Technical field
[0001]
　The present invention relates to a structure of a gas introduction hole socket portion such as a nozzle or a plug made of a refractory or the like having a function of blowing gas into a molten metal or a function of blowing gas to a specific portion.
Background technology
[0002]
　Nozzles and plugs in which a space such as a slit for gas distribution/storage, pressure equalization, etc., a porous refractory material (hereinafter also simply referred to as “gas pool”) are arranged inside the refractory material forming the main body Etc. (hereinafter also simply referred to as “main body” or “refractory body”), a socket is installed in the refractory body or a metal case surrounding the refractory body in order to introduce gas into the gas pool. ，It is common to connect a gas introduction pipe to the socket.
[0003]
　When connecting a gas introduction pipe to such a socket, there is a problem that gas leaks between the refractory body and the socket. If a gas leak occurs, it may cause nozzle clogging, a decrease in molten metal agitation ability due to gas, and a decrease in productivity and quality of slabs.
[0004]
　For example, in Patent Document 1, since the socket expands when the socket is welded to the metal plate, a gap is generated between the socket and the seal material after welding, the metal plate is deformed by the welding heat, or the seal material is generated by the welding heat. It has been pointed out that leakage occurs due to foaming of the sealing material due to vaporization of residual water inside and crystal water in the sealing material (paragraph 0007).
　In order to prevent such a gas leak, Patent Document 1 discloses a gas blowing continuous casting in which a socket having a collar or a step portion on the rear end side for connecting a gas introduction pipe is attached to a socket hole via a sealing material. We have proposed a refractory socket mounting structure.
　Then, in Patent Document 1, "the contact area between the flange or the stepped portion of the socket and the sealing material is large, so that the sealing material is resistant to external stress when the gas pipe is screwed, and the sealing material is less likely to crack. ，It has the effect of suppressing leakage during use.Since a socket with a collar or a step is attached, there is no need for welding, and cracks in the sealing material and foaming of the sealing material due to expansion of the socket during welding are eliminated. Even if a crack occurs in the sealing material of the threaded portion of the socket, there is an effect of suppressing the leakage because the sealing material is strongly adhered to the flange or step portion (paragraph 0015). ..
[0005]
　In addition, in Patent Document 2, based on Patent Document 1, in order to eliminate adverse effects due to welding between the metal reinforcing plate and the socket and to eliminate leakage when introducing gas, the upper surface of the socket mounting hole of the casting nozzle of the metal reinforcing plate is positioned. A method is disclosed in which a through hole is provided and a sealing material is injected from the through hole, so that the socket and the metal reinforcing plate are attached to the socket attachment hole provided on the side surface of the casting nozzle via the sealing material.
[0006]
　Further, in Patent Document 3, the second supporting element (9b) inserted into the cylindrical hole sandwiches the gasket (14) together with the first supporting element (13), and the rod (9a) compresses the gasket. In order to do so, it has been shown to bring the two support elements closer together.
　In this Patent Document 3, a "supporting element" corresponding to a collar is provided at a tip side of a "rod (9a)" corresponding to a socket, that is, a main body inside direction side ("second support element (9b)") and a main body outside direction side. (“First support element (13)”) and compresses the gasket (14) sandwiched between these collars, so that the gasket extends between the refractory body at the portion extending in the radial direction of the socket. It is intended to prevent the gas leak by closely contacting each other.
Advanced technical literature
Patent literature
[0007]
Patent Document 1: Japanese Patent Laid-Open No. 2002-1498
Patent Document 2: Japanese Patent Laid-Open No. 2001-87845
Patent Document 3: Japanese Patent Publication No. 2006-516482
Summary of the invention
Problems to be Solved by the Invention
[0008]
　In the structures of Patent Document 1 and Patent Document 2, gas leakage cannot be prevented by the seal material on the outer peripheral portion of the socket (for example, reference numeral 52 in the patent document 1 or socket outer peripheral portion 8 in the patent documents 1 and 2). This is also clear from these patent documents themselves.
　Further, in Patent Documents 1 and 2, instead of the sealing material installed on the outer peripheral surface of the socket, the sealing material is arranged between the brim or stepped portion installed on the socket rear end side, that is, near the outermost periphery of the main body, and the refractory body. Attempts to prevent gas leaks with the sealing material. However, even if these structures and methods of Patent Documents 1 and 2 are applied to a nozzle or the like, it is still impossible to sufficiently prevent gas leakage.
[0009]
　Further, in Patent Document 3, a gasket that is sandwiched in the axial direction of the socket and compressed is extended in the radial direction so as to closely contact the refractory body and prevent gas leakage. In the same manner as above, a sufficient degree of adhesion cannot be obtained only with such a socket outer peripheral surface, and even with such a gasket contact that converts the force compressed in the socket axial direction into the socket radial direction, Since there is no sealing material between each of the two brims and the refractory body, it is not possible to sufficiently prevent gas leakage.
[0010]
　The problem to be solved by the present invention is to prevent gas leakage at the socket portion of the gas introduction hole.
Means for solving the problem
[0011]
　It is considered that the gas leakage cannot be sufficiently prevented even by the structures and methods of Patent Documents 1 to 3 as follows.
(1) When welding the flange or the stepped portion to a metal case or the like on the outer periphery of the main body, the flange portion or the stepped portion is still deformed by the heat, and a gap is created in the sealing material.
(2) Moreover, since the metal case surrounds the outer peripheral surface of the main body, it is substantially unconstrained on the outer peripheral side, that is, outside in the radial direction of the main body, and is more easily deformed.
(3) The above (1) and (2) are not only for welding, but also from the inside of the main body during use due to molten metal, or the arrangement environment (for example, the outer periphery of the main body, the atmosphere outside the socket, the arrangement of heat insulating materials). The heat received from the outer peripheral side due to the structure, etc., and their nonuniform temperature distribution lead to deformation of the flange or stepped portion.
(4) When the flange or the step is welded to the metal case or the like on the outer periphery of the main body, a gap or the like still occurs inside the sealing material due to the non-uniform alteration of part of the sealing material due to the heat.
(5) In addition to the welding in the above (1) and (4), the sealing material is exposed to a high temperature of more than 100° C. in the drying process, especially by rapid heating, so that moisture etc. inside the sealing material is rapidly vaporized. There are gaps inside and around.
[0012]
　The present invention provides a structure of a socket part for eliminating these causes. That is, the gist of the present invention is the structure of the following gas introduction hole socket portion 1-9.　
1
　The structure of a gas introduction hole socket portion including a socket for connecting a gas supply pipe to the gas introduction hole to the inside of the refractory,
　wherein the gas introduction hole is on the outer side of the refractory body (hereinafter simply referred to as “outer side”). A metal plate surrounding a part or all of the refractory body is provided around the
　end, and the socket has the outer end and the refractory body inward direction side (hereinafter simply referred to as “inside”). ) A flange is provided between the flange and the
　end, the surface on the inner end side of the
　flange is adhered to the refractory body via a sealing material, and the surface on the outer end side of the flange is , An outer end portion of the metal plate or the refractory body through a layer made of a low thermal conductive material having a thermal conductivity of 40 (W/(m·K)) or less at room temperature (hereinafter referred to as “low thermal conductive material layer”)
　The structure of the gas introduction hole socket portion facing the other flange installed on the side, and the metal plate and a part or all of the outer periphery of the socket are joined.
2 When the
　thickness of the low thermal conductive material layer is L (mm) and the thermal conductivity of the low thermal conductive material at room temperature is λ (W/(m·K)), the following expression 1 is satisfied. Structure of the gas introduction hole socket portion described.
　≦ 0.1359L Ramuda 2 -0.7849L Tasu 1.4793 · · · Formula
1 3
　3. The structure of the gas introduction hole socket portion according to 1 or 2 above, wherein the low thermal conductive material is a material having a thermal conductivity of 2.5 (W/(m·K)) or less at room temperature.
4
　The structure of the gas introduction hole socket portion according to 1 or 2 above, wherein the low thermal conductive material is a material having a thermal conductivity of 0.5 (W/(m·K)) or less at room temperature.
5
　The structure of the gas introduction hole socket portion according to 1 or 2 above, wherein the low thermal conductive material is air.
6
　The surface on the inner end side of the flange between the outer end portion and the inner end portion and the surface of the refractory body that is in contact with the surface through the sealing material are inside the central axis of the gas introduction hole. The structure of the gas introduction hole socket part according to any one of 1 to 5 above, which is a conical shape having an angle of more than 0 degree and less than 90 degrees from the direction toward the outside of the gas introduction hole.
7
　The thickness L (mm) of the low thermal conductive material layer satisfying the above formula 1 is defined by the angle θ (degree) with respect to the socket axial direction of the surface of the inner flange of the socket that contacts the refractory body through the seal material, and Fluctuation length ΔL (mm) in the axial direction of the socket determined according to fluctuation length Δt (mm) of thickness in the direction perpendicular to the surface of the sealing material between the refractory on the inner end side of the flange. 3. The structure of the gas introduction hole socket portion according to 2 above, which has the following length.
8
　The structure of the gas introduction hole socket portion described in 7 above, wherein ΔL satisfies the following expression 2.
　ΔL ≦ 5.76 × Δt / sinθ ··· Formula
2 9
　9. The structure of the gas introduction hole socket portion according to 7 or 8 above, wherein ΔL is 23 mm or less and L is 43 mm or less.
The invention's effect
[0013]
　First, the seal part that most directly affects the gas leak behavior is installed at a position far from the outer periphery of the main body, that is, on the inner side of the refractory body. In other words, the tsuba is installed between the outer end and the inner end of the socket on the inner end side as much as possible, and the sealant is installed between the inner end side surface of the tsuba and the refractory body. ..
　That is, the sealing function is not substantially imparted to or strengthened between the metal plate around the outer edge of the refractory body (hereinafter also referred to as the “main body outer peripheral side”) that is easily deformed. Moreover, the presence of the tsuba inside the main body allows the tsuba to have a substantially uniform radius even if heat is received to some extent from the inside (hereinafter also referred to as “inner side”) or the outside (hereinafter also referred to as “outer side”). Since it expands in the direction, uneven deformation is less likely to occur, a gap is less likely to be formed on the surface where the collar and the sealing material contact, and the radial sealing property is improved and at the same time the collar is firmly fixed.
　At the same time, local heat reception of the sealing material or partial deterioration due to the local heat reception hardly occurs.
　In addition, even if a mechanical force is applied to the socket near the surface on the outer peripheral side of the main body in the radial direction with respect to its axis, the seal part is located inside the main body far from the outer peripheral surface of the main body, and the seal part is wider than the socket cross section. Since it has an area and is firmly fixed, peeling of the seal portion due to external force such as moment applied to the socket is unlikely to occur.
[0014]
　Furthermore, the surface on the outer end side of the flange faces the metal plate on the outer peripheral side of the main body or another flange installed on the outer peripheral side end of the main body through the layer of the low thermal conductive material, so that The heat conduction up to the tsuba is minimized. Thereby, the non-uniform deformation of the collar portion can be further suppressed. Local high temperature due to external high temperature or non-uniform atmosphere environment, non-uniform heat insulating material arrangement environment, etc., especially when exposed to temperature exceeding 100°C during welding process and drying process after socket installation. Even if a state or the like occurs, it is possible to suppress the effect of heat transfer such as a non-uniformity on the collar portion or a rapid temperature rise of the seal portion in which moisture or the like existing therein is vaporized rapidly.
[0015]
　Since the sealability between the socket and the refractory body is enhanced by the present invention, it is not necessary to secure strict sealability between the socket and the metal case on the outer peripheral side of the refractory body via the low thermal conductive material layer.
　Therefore, it is less necessary to weld the entire circumference of the socket (or the flange on the outer peripheral side of the refractory body) to the metal case on the outer peripheral side of the refractory body. That is, the minimum amount of welding, such as at one to three or more places, where the socket (or the flange on the outer peripheral side of the refractory body) can be fixed to the metal case on the outer peripheral side of the refractory body without causing deformation or misalignment. It is possible to As a result, the heat load on the seal part can be further reduced, deformation of the socket (or the flange on the outer peripheral side of the refractory body) and the metal case on the outer peripheral side of the refractory body can be reduced, and the socket mounting work efficiency can be improved. Can be improved.
Brief description of the drawings
[0016]
FIG. 1 is an image view showing a cross section of a surface passing through a central axis of a gas introduction hole in an example of a structure of a gas introduction hole socket portion of the present invention in which a seal portion has a structure perpendicular to a socket axis direction. In (a), the inner collar is installed near the outer periphery of the refractory body, and the inner edge of the refractory body of the socket is present in the refractory body. (b) shows that the inner collar is the refractory body. The example (c), which is installed near the outer circumference and extends the inner end of the refractory body of the socket to the gas pool section in the refractory body, has the same structure as (b) above, Example of further extending the length of the low thermal conductive material layer by installing the part near the inside of the refractory body
[Fig. 2] An example of the structure of the gas introduction hole socket part of the present invention in which the seal part has an inclined structure. It is an image figure showing a section of a field which passes along a central axis of an introduction hole. (A) is an example in which the inner collar part is installed near the outer periphery of the refractory body, and the inner end of the refractory body of the socket is present in the refractory body. (b) shows the inner collar part as shown in FIG. Example in which the length of the low thermal conductive material layer is increased by installing it inside the refractory body more than in (a), and the inside end of the refractory body of the socket is extended to the gas pool part in the refractory body
[Fig. 3] It is an image view showing a cross section of a surface passing through the central axis of the gas introduction hole in another example of the structure of the gas introduction hole socket part of the present invention in which the seal portion has an inclined structure and extends to the end. (A) is an example in which the inner collar part is installed near the outer periphery of the refractory body and the inner end of the refractory body of the socket is present in the refractory body. Example in which the length of the low thermal conductive material layer is increased by installing it inside the refractory body more than in (a), and the inside end of the refractory body of the socket is extended to the gas pool part in the refractory body
[Fig. 4] FIG. 4 is an image view showing a cross section of a surface passing through a central axis of a gas introduction hole in an example of a structure of a gas introduction hole socket portion of the present invention in which a flange is not provided on an outer end side of the socket.
[Fig. 5] Fig. 5 is an example of the structure of the gas introduction hole socket portion of the present invention in which a screw portion is installed on the outer periphery near the socket end portion on the outer side of the refractory body, and shows a cross section of a surface passing through the gas introduction hole central axis. It is an image figure.
[Fig. 6] Relationship between the thermal conductivity λ (W/(m·K)) of the low thermal conductive material at room temperature when the sealing material reaches 100°C in relation to the axial thickness Lmm of the socket of the low thermal conductive material layer. It is a figure (illustration of Formula 3) shown.
[Fig. 7] The relationship between the angle θ (degrees) of the sealing surface and the variation length ΔL (mm) of the thickness of the sealing material in the socket axial direction is shown by the variation length Δt (thickness of the thickness in the direction perpendicular to the sealing surface. It is a figure shown for every (mm).
FIG. 8 is a diagram showing a case where ΔL (mm) with respect to Δt (mm), that is, ΔL (mm) is maximized when the angle θ (degree) is 10 (degrees) in FIG. 8.
FIG. 9 is an image diagram showing a cross section of a surface passing through the central axis of the gas introduction hole in an example of the structure of a conventional gas introduction hole socket portion.
MODE FOR CARRYING OUT THE INVENTION
[0017]
　As described above, one of the causes of the gas leak in the vicinity of the socket portion is the deformation of a part of the socket at the time of mounting the socket or the deterioration of the sealing material. Especially when the outermost periphery of the socket is welded to a metal plate installed on the outer periphery of the refractory body, part of the socket is deformed by the heat during the welding and a gap or the like is formed between the socket and the seal material. When the temperature of the sealing material containing the abruptly rises to the vaporization temperature of the water, that is, 100° C. or higher, defects such as gas bubbles can pass through the sealing material.
　After the sealing material is installed, generally, the refractory body (including the one having a structure such as a nozzle) is subjected to heat treatment such as drying for the purpose of removing moisture or improving strength.
　In addition to the causes caused by the welding as described above, rapid heat conduction from the outer peripheral portion during heat treatment such as drying may also be a cause.
[0018]
　The present invention is to rapidly volatilize volatile components in a sealing material containing a volatile substance such as water due to heat from the outer peripheral side of the refractory body such as welding, that is, the outside of the socket, to such an extent that the structure is destroyed. Prevent.
[0019]
　The material forming the socket, that is, iron-based metal, has a thermal conductivity of about 70 to about 80 (W/(m·K)) at room temperature. As in many prior arts, the socket maintains the size of the diameter between both ends in the axial direction, and even if the socket has a sealing material, the sealing surface is within the range of the diameter. There is.
　On the other hand, in the present invention, the low heat conductive material layer is formed between both ends in the axial direction of the socket to suppress the heat conduction in the axial direction of the socket, thereby preventing the temperature of the seal portion from rapidly increasing.
　In this temperature range, heat transfer is mainly conducted, and radiation and convection can be ignored.
[0020]
　The low thermal conductive material may have a lower thermal conductivity than the material forming the socket, that is, an iron-based metal, but it is preferable that the low thermal conductivity is as low as possible because it is less likely to be affected by thermal fluctuations and a more reliable effect can be obtained. .
[0021]
　The present inventors have found that the thermal conductivity λ(W/(m·K)) of the low thermal conductive material at room temperature when the temperature of the sealing material in contact with the flange installed on the inner end side of the refractory body reaches 100°C. However, it was found by unsteady thermal calculation that the following Equation 3 was satisfied with the axial thickness L (mm) of the socket of the low thermal conductive material layer.
　λ = 0.1359L 2 -0.7849L + 1.4793 ・・・Equation 3
　λ less than or equal to λ in this expression 3, that is, λ≦If a low thermal conductive material having a value on the right side of expression 3 is applied, the temperature of the sealing material is 100° C. Will not be exceeded. The above expression 1 expresses this relationship.
　The relationship between L and λ based on this equation is shown in FIG.
[0022]
　This is based on the value measured in actual work of welding the entire circumference of the socket to the metal case on the outer peripheral side of the refractory body. Although the welding work time varies depending on the method and the like, in the present invention, it is about 10 seconds, and the maximum is about several tens of seconds.
[0023]
　In this calculation, the temperature of the welded portion was 600° C. (measured value with a thermoviewer), and the bulk specific gravity of the low thermal conductive material was 3.0. When the bulk specific gravity is lower than this, λ becomes smaller for the same value of L.
　In other words, the thickness L is a thickness that can be arbitrarily set and is determined according to design items, that is, the structure and shape of the refractory body. By selecting a material having a thermal conductivity satisfying Equation 1, the temperature of the sealing material can be set to approximately 100° C. or lower, and the socket can be installed without causing defects in the sealing material.
[0024]
　In the present invention, when the maximum thermal conductivity of the refractory is set to 40 (W/(m·K)), the required maximum thickness of the low thermal conductive material layer is set to approximately 20 mm according to the above equation 2, Thus, the thickness L (mm) can be set within a range that satisfies the above expression 1.
[0025]
　When a liquid such as a solvent other than water is used as the sealing material, the vaporization temperature of the solvent is basically used as a standard, as in the case of water. In general, the vaporization temperature of non-aqueous solvents used for refractories is higher than 100°C, so if the above Equation 1 based on 100°C is satisfied in the case of non-aqueous solvents, the sealing material will be less prone to defects Become.
[0026]
　From the viewpoint of more reliably suppressing the temperature rise of the sealing material, it is preferable that the material applied to the low thermal conductive material layer has a low thermal conductivity. For example, in addition to metals, carbon, compounds with strong covalent bond, etc., it is a refractory mainly composed of oxides, etc. Considering the ease of installation, etc., alumina-based, alumina-silica-based, silica-based mortar etc. It is more preferable to use a material having a thermal conductivity of about 2.5 (W/(m·K)) or less at room temperature.
　This low thermal conductive material layer does not support the socket as a structure and does not have to withstand mechanical stress, so its thermal conductivity is about 0.5 (W/(m·K)) or less at room temperature. It may be a low-strength material such as a heat insulating material, an inorganic fiber, or a mixture thereof.
　Furthermore, this low thermal conductive material is air whose thermal conductivity at room temperature is extremely low at about 0.024 (W/(m·K)), that is, the low thermal conductive material layer is a space, and it has the most adiabatic effect. It is most preferable because of its high cost, easy manufacturing and low cost.
　The above-mentioned thermal conductivity is according to JIS R2251.
[0027]
　The surface of the refractory body that is in contact with the surface on the inner end side of the flange between the outer end portion and the inner end portion installed in the socket and the surface through the seal material is the central axis of the gas introduction hole (socket shaft). The same as the above), the diameter of the gas introduction hole may be expanded outwardly. That is, a shape having an angle of more than 0 degrees and less than 90 degrees (hereinafter also simply referred to as “inclination”) with respect to the central axis of the gas introduction hole from the inner side of the main body may be used.
　As a result, when an external force is applied in the axial direction of the socket, the socket moves to the central axis side of the gas introduction hole of the refractory body, so that the thickness between the outer peripheral surface of the socket and the refractory body becomes uniform, The uniformity of the sealing material also increases.
　Further, when heat is applied during use, the socket expands, but since the expansion is larger than that of the refractory body, this inclined surface can further enhance the adhesiveness of the layer of the sealing material and local It is possible to avoid stress concentration, and reduce the risk of breaking the refractory body around the socket.
[0028]
　More preferably, the inclined portion of the collar extends to the socket end portion on the inner side of the refractory body (see FIG. 3). As a result, the straight part on the outer peripheral surface of the socket is reduced, the socket can be installed easily and with high accuracy, and the part between the inner end side of the tsuba and the surface of the refractory body, which is an important part for the sealing property. Since the sealing material portion also becomes wider and more uniform, the sealing performance can be further improved.
[0029]
　The thickness L of the low thermal conductive material layer portion in the axial direction of the socket is preferably as long as possible in order to enhance the heat insulating effect, and the brim inside the refractory body is preferably located as far as possible inside the refractory body. (Refer to Fig. 1(c), Fig. 2(b), Fig. 3(b))
　Also, by locating the collar on the inside of the refractory body toward the inside of the refractory body as much as possible, the fixing force of the socket against the external force from the outside of the socket is also increased. Stabilize. For the same reason, it is preferable that the length of the socket itself, that is, the length up to the end portion of the refractory body inward direction be as long as possible. (See FIG. 1(b), FIG. 1(c), FIG. 2(b), and FIG. 3(b))
[0030]
　This inclination angle θ (degree) can be arbitrarily set depending on the size of the collar, the diameter and accuracy of the socket installation portion of the refractory body, the accuracy of the sealing surface of the socket and the refractory body, and the like.
[0031]
　The thickness of the sealing material may vary depending on the configuration/property of the sealing material, the tolerance in the shape specifications of the socket and the refractory body, and the variation in the work when the socket is installed.
　The flange on the outer end side of the refractory body of the socket is separated from the other parts of the socket, and after the other part is installed, the flange on the outer end side of the refractory body is welded to the socket and the metal. Such a phenomenon is likely to occur especially when installed on a plate.
[0032]
　Further, when the sealing surface has an inclined structure, the smaller the inclination angle θ (degree) is, the smaller the fluctuation length of the sealing material in the axial direction of the socket with respect to the thickness fluctuation Δt (mm) in the direction perpendicular to the sealing surface. ΔL (mm), that is, the fluctuation of the position of the socket in the radial direction of the refractory body becomes large.
　This geometrically has the relationship of the following expression 3. 　.DELTA.L
　=.DELTA.t/
sin.theta ....Equation 4 Each .DELTA.L when .DELTA.t is set to 1, 2, 3, 4 mm is shown in FIG.
[0033]
　For example, the inclination angle θ is set to 10 (degrees), which is considered to be the minimum in reality, and the variation length Δt of the thickness of the sealing material in the direction perpendicular to the sealing surface is set to 4 (mm), which is considered to be the maximum in reality. In this case, the fluctuation length ΔL (mm) on the socket axial direction side is about 23 (mm).
　For example, as shown in FIG. 8, the relationship with ΔL when Δt is different when the inclination angle θ is 10 (degrees) is approximately according to the following Expression 4.
　ΔL=5.76×Δt
　( Equation 5 ) Thus, L (mm) is the required length according to the above Equation 2, and thus the variation length of the inclination angle θ and the thickness of the sealing material in the direction perpendicular to the sealing surface. It is preferable to set the length to the sum of ΔL (mm) calculated from the relationship of the length Δt.
[0034]
　If Equation 4 and Equation 5 are combined into one, the above Equation 2, that is, ΔL≦5.76×Δt/sin θ is obtained.
[0035]
　The size of the collar is from the viewpoints of (1) increasing the area of ​​the seal part, (2) ensuring or enhancing the heat insulating effect of the low thermal conductive material layer, (3) enhancing the mechanical stability against external force applied to the socket, etc. ，It is preferable to make it as large as possible.
　In this case, the refractory body may be destroyed due to the shape of the brim portion of the refractory body constituting the nozzle, the plug, etc., that is, the curvature in the case of a circular shape, the distance from the end, etc. The size should not be too large. In the case of a circular shape, the brim may be curved according to the curvature.
[0036]
　It is necessary to join the metal plate on the outer peripheral side of the refractory body and a part or all of the outer periphery of the socket to fix the socket.
　As this joining method, an appropriate method such as spot welding a part of the outer circumference of the socket, full welding, screwing as a screw structure, or the like can be adopted. The metal plate on the outer peripheral side of the refractory body and the outer periphery of the socket do not necessarily have to be hermetically sealed, but may be fixed to each other.
　This fixing position may be the outer peripheral portion of the socket (7 in FIG. 4), or a collar may be further installed on the outer periphery of the socket and may be near the outermost periphery of the flange (7 in FIG. 1 to 3).
Example
[0037]
[Embodiment A] With the
　　structure shown in FIG. 1, the thickness of the low thermal conductive material layer in the socket axial direction is 10 mm, and the thermal conductivity at room temperature is about 2.5 (W/(mK)). Example 1 using the alumina mortar of Example 1, Example 2 using the low thermal conductive material as a heat insulating material having a thermal conductivity of about 0.5 (W/(m·K)) at room temperature, and using the low thermal conductive material using air Regarding Example 3, the presence or absence of air leakage was compared in a laboratory test at room temperature with Comparative Example 1 having a conventional structure shown in FIG.
　The metal plate on the outer peripheral side of the refractory body and the entire outer periphery of the socket were welded to the socket.
　The pressure of the pressurized air for leak confirmation was set to 0.5 MPa at maximum, and there was a leak when there was a pressure drop after standing for 3 hours, and there was no leak when there was no pressure drop.
　As a result, Comparative Example 1 had a leak, whereas Examples 1, 2 and 3 had no leak.
[0038]
[Example B]
　Example B is a result of subjecting Example 3 to actual operation. The refractory body was an upper nozzle for continuous casting.
　As a result, the leakage frequency of the conventional structure of Comparative Example 1 was about 3%, whereas that of Example 3 was no leakage, that is, 0%.
Explanation of symbols
[0039]
　1 Seal part that enhances the adhesiveness most in the area where the sealant exists
　2 Sealant
　3 Collar
　4 installed inside the refractory body 4 Low thermal conductive material layer
　5 Collar
　6 installed outside the refractory body 6 Installed around the refractory body Metal plate
　7 Joint between socket and metal plate installed on the outer periphery of the refractory body
　8 Screw portion
　9 Gas introduction hole
　10 Gas introduction hole and socket shaft
　11 Gas pool
　20 Socket
　30 Refractory body
　L Fire resistance of low thermal conductive material layer Thickness from the flange installed on the outside of the refractory body or the metal plate installed on the outer periphery of the
　refractory body θ The angle of the inclined part of the flange installed on the inside of the refractory body
The scope of the claims
[Request 1]
　A structure of a gas introduction hole socket portion including a socket for connecting a gas supply pipe to a gas introduction hole to the inside of the refractory,
　wherein the gas introduction hole is on the outer side of the refractory body (hereinafter simply referred to as "outside"). A metal plate surrounding part or all of the refractory body is provided around the
　end, and the socket has the outer end and the refractory body inward direction side (hereinafter simply referred to as "inside"). A flange is provided between the flange and the
　end, the surface of the flange on the inner end side is adhered to the refractory body via a sealing material, and the surface of the
　flange on the outer end side is An outer end side of the metal plate or the refractory body through a layer made of a low thermal conductive material having a thermal conductivity of 40 (W/(m·K)) or less at room temperature (hereinafter referred to as “low thermal conductive material layer”)
　The structure of the gas introduction hole socket portion facing the other flange installed in the above, and the metal plate and a part or all of the outer periphery of the socket are joined.
[Request 2]
　The following formula 1 is satisfied when the thickness of the low thermal conductive material layer is L (mm) and the thermal conductivity of the low thermal conductive material at room temperature is λ (W/(m·K)). Structure of the gas introduction hole socket portion described.
　λ ≦ 0.1359L 2 −0.7849L+1.4793...Equation 1
[Request 3]
　The structure of the gas introduction hole socket part according to claim 1 or 2, wherein the low thermal conductive material is a material having a thermal conductivity of 2.5 (W/(m·K)) or less at room temperature.
[Request 4]
　The structure of the gas introduction hole socket part according to claim 1 or 2, wherein the low thermal conductive material is a material having a thermal conductivity of 0.5 (W/(m·K)) or less at room temperature.
[Request 5]
　The structure of the gas introduction hole socket portion according to claim 1 or 2, wherein the low thermal conductive material is air.
[Request 6]
　The surface on the inner end side of the flange between the outer end portion and the inner end portion and the surface of the refractory body that is in contact with the surface via the sealing material are inwardly directed with respect to the central axis of the gas introduction hole. The structure of the gas introduction hole socket part according to any one of claims 1 to 5, which is a conical shape having an angle of more than 0 degree and less than 90 degrees from the starting point to the outside direction of the gas introduction hole.
[Request 7]
　The thickness L (mm) of the low thermal conductive material layer satisfying the above formula 1 is defined by the angle θ (degree) with respect to the socket axial direction of the surface of the flange on the inside of the socket that contacts the refractory body through the sealing material and the flange. No longer than the fluctuation length ΔL (mm) in the axial direction of the socket, which is determined according to the fluctuation length Δt (mm) of the thickness at right angles to the surface of the seal material between the refractory on the inner end side. The structure of the gas introduction hole socket portion according to claim 2, wherein the length is the sum of the above.
[Request 8]
　The structure of the gas introducing hole socket portion according to claim 7, wherein the ΔL satisfies the following expression 2.
　ΔL ≤ 5.76×Δt/sin θ... Equation 2
[Request 9]
　The structure of the gas introduction hole socket part according to claim 7 or 8, wherein the ΔL is 23 mm or less and the L is 43 mm or less.