Burner and heat treatment facility

Abstract

A burner is provided with: a combustion tube forming a combustion chamber for burning a fuel; at least one nozzle pipe for injecting a gas containing the fuel or air into the combustion chamber, the at least one nozzle pipe being disposed inside the combustion tube; and a nozzle plate extending, inside the combustion tube, along a plane perpendicular to an axial direction of the combustion tube, and having at least one hole into which a tip portion of the at least one nozzle pipe is fitted, respectively. A hole forming portion of the nozzle plate in which the at least one hole is formed includes SiC or graphite, and the tip portion of the nozzle pipe includes an Fe-Cr-Al based alloy.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a burner and a heat treatment facility.BACKGROUND

[0002] In heat treatment of a metal plate or the like, a burner that burns gas fuel is used.

[0003] Patent Document 1 describes a burner provided with a nozzle pipe for injecting fuel into a combustion chamber formed inside a combustion tube. In this burner, the nozzle pipe is disposed so as to extend along the axial direction of the combustion tube and is supported by a nozzle plate disposed inside the combustion tube. The nozzle plate is disposed so as to extend along a plane perpendicular to the axial direction of the combustion tube so that the combustion chamber is formed, and a tip portion of the nozzle pipe is fitted into a hole provided in the nozzle plate.Citation ListPatent Literature

[0004] Patent Document 1: JP6823730BSUMMARYProblems to be Solved

[0005] By the way, depending on the operating conditions of the heat treatment facility or the structure of the combustion tube, the nozzle plate becomes hot, and the nozzle plate and the nozzle pipe fitted into the hole of the nozzle plate may adhere (fuse) to each other. If the nozzle plate and the nozzle pipe adhere to each other, the heat resistance of the nozzle decreases, which may lead to failure of the burner due to deformation or thinning of the nozzle, or may hinder maintenance.

[0006] In view of the above circumstances, an object of at least one embodiment of the present invention is to provide a burner and a heat treatment facility capable of suppressing adhesion between members.Solution to the Problems

[0007] A burner according to at least one embodiment of the present invention is provided with: a combustion tube forming a combustion chamber for burning a fuel; at least one nozzle pipe for injecting a gas containing the fuel or air into the combustion chamber, the at least one nozzle pipe being disposed inside the combustion tube; and a nozzle plate extending, inside the combustion tube, along a plane perpendicular to an axial direction of the combustion tube, and having at least one hole into which a tip portion of the at least one nozzle pipe is fitted, respectively. A hole forming portion of the nozzle plate in which the at least one hole is formed includes SiC or graphite, and the tip portion of the nozzle pipe includes an Fe-Cr-Al based alloy.

[0008] Further, a heat treatment facility according to at least one embodiment of the present invention is provided with: the above-described burner; and a fuel supply line for supplying a fuel to the burner.Advantageous Effects

[0009] At least one embodiment of the present invention provides a burner and a heat treatment facility capable of suppressing adhesion between members.BRIEF DESCRIPTION OF DRAWINGS

[0010] FIG. 1 is a schematic cross-sectional view of a burner according to an embodiment. FIG. 2 is an enlarged view of a front portion of the burner shown in FIG. 1. FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2. FIG. 4 is a schematic cross-sectional view of a front portion of a burner according to an embodiment. FIG. 5 is a schematic cross-sectional view of a front portion of a burner according to an embodiment. FIG. 6 is a schematic cross-sectional view of a front portion of a burner according to an embodiment. FIG. 7 is a schematic diagram showing a gas flow in a combustion chamber of the burner. FIG. 8 is a schematic cross-sectional view of a front portion of a burner according to an embodiment. DETAILED DESCRIPTION

[0011] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It is intended, however, that unless particularly identified, dimensions, materials, shapes, relative positions, and the like of components described in the embodiments shall be interpreted as illustrative only and not intended to limit the scope of the present invention.

[0012] FIG. 1 is a schematic cross-sectional view of a burner according to an embodiment. FIG. 2 is an enlarged view of a front portion of the burner 1 shown in FIG. 1. FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2. FIGs. 4 to 6 and 8 are each a schematic cross-sectional view of a front portion of the burner 1 according to an embodiment. Herein, in the axial direction of the burner 1 (or in the axial direction of a combustion tube 24), the front side is a side on which an opening portion 25 of a combustion tube 24 is positioned, and the rear side is opposite to the front side.

[0013] As shown in FIGs. 1 to 6, the burner 1 includes a combustion tube 24 forming a combustion chamber 23, at least one nozzle pipe 40 (41, 42) respectively forming at least one combustion nozzle 2 (3, 4) for injecting a gas containing fuel or air into the combustion chamber 23, and a nozzle plate 30 for supporting the at least one nozzle pipe 40. In the illustrated embodiment, the burner 1 includes a plurality of nozzle pipes 40 (41, 42).

[0014] The combustion tube 24 includes a tubular member extending along the axial direction (the direction of the central axis O (see FIG. 2)) and forms the combustion chamber 23 for burning fuel. Typically, the combustion chamber 23 is formed by an inner peripheral surface at a front end portion of the combustion tube 24 and the nozzle plate 30. The combustion chamber 23 is formed at the front end portion of the combustion tube 24 and communicates with the opening portion 25 of the combustion tube 24.

[0015] Each of the at least one nozzle pipe 40 is disposed inside the combustion tube 24 and is configured to inject a gas containing fuel or air into the combustion chamber 23. Each of the at least one nozzle pipe 40 may be disposed so as to extend along the axial direction of the combustion tube 24.

[0016] The burner 1 includes an ignition rod 10 for igniting the gas containing fuel. The ignition rod 10 is inserted through any one of the at least one nozzle pipe 40. As shown in FIG. 1, the ignition rod 10 is attached to an ignition plug 9. Further, as shown in FIG. 2, the ignition rod 10 is covered with an insulation tube 11 formed of an insulator except for the tip portion so as to be insulated from surrounding members. For ignition of the burner 1, a spark is generated at the tip portion of the ignition rod 10 to ignite the fuel-containing gas injected from the nozzle pipe 40.

[0017] In the exemplary embodiment shown in FIGs. 1 to 6, the ignition rod 10 is disposed inside a first nozzle 3 among the plurality of combustion nozzles 2 (3, 4). Further, the ignition rod 10 is not disposed in a second nozzle 4 other than the first nozzle 3 among the plurality of combustion nozzles 2 (3, 4). That is, the plurality of nozzle pipes 40 respectively forming the plurality of combustion nozzles 2 include a first nozzle pipe 41 through which the ignition rod 10 is inserted (the nozzle pipe 40 forming the first nozzle 3) and a second nozzle pipe 42 other than the first nozzle pipe 41 (the nozzle pipe 40 forming the second nozzle 4 and through which the ignition rod 10 is not inserted).

[0018] The nozzle plate 30 is disposed inside the combustion tube 24 so as to extend along a plane perpendicular to the axial direction of the combustion tube 24. As shown in FIG. 2, the nozzle plate 30 has at least one hole 31 into which tip portions (front end portions) 41a, 42a of the nozzle pipes 40 (41, 42) can be fitted, respectively. The hole 31 is provided so as to penetrate the nozzle plate 30 in the axial direction.

[0019] As shown in FIGs. 2 and 4 to 6, the tip portions (front end portions) 41a, 42a of the nozzle pipes 40 (41, 42) are respectively fitted into the holes 31 of the nozzle plate 30. Further, rear end portions (end portions opposite to the tip portions 41a, 42a) of the nozzle pipes 40 (41, 42) are fitted into holes 17 formed in a front plate 14 located rearward of the nozzle plate 30. Thus, the nozzle pipes 40 (41, 42) are supported so as to extend along the axial direction of the combustion tube 24.

[0020] A heat resistant material 36 may be provided around the nozzle pipe 40 between the nozzle plate 30 and the front plate 14.

[0021] The plurality of combustion nozzles 2 (3, 4) may be arranged in the circumferential direction around the central axis O of the combustion tube 24, for example, as shown in FIG. 3. Further, the plurality of combustion nozzles 2 (3, 4) may be arranged at different radial positions. In the example shown in FIG. 3, the plurality of combustion nozzles 2 include a first nozzle 3 disposed at the center portion in the radial direction, six second nozzles 4 arranged circumferentially on the inner peripheral side, and ten second nozzles 4 arranged circumferentially on the outer peripheral side.

[0022] In some embodiments, the first nozzle 3 may not be disposed at the center portion in the radial direction. For example, the plurality of combustion nozzles 2 arranged circumferentially may include one first nozzle 3 and a plurality of second nozzles 4.

[0023] A first gas containing fuel is supplied to the first nozzle 3 through a first gas passage 6. A second gas containing fuel or air is supplied to the second nozzle 4 through a second gas passage 8. The first gas and the second gas supplied to the first nozzle 3 and the second nozzle 4 may be fuel gas, air, or premixed gas in which fuel and air are mixed in advance.

[0024] In the burner 1, a flame is generated by burning the gas containing fuel injected from the outlets 3a, 4a of the first nozzle 3 and the second nozzle 4, and this flame is ejected from the opening portion 25 formed at the tip portion of the combustion tube 24. The flame F thus ejected from the combustion tube 24 is used for heat treatment of an object to be treated 101.

[0025] The first gas passage 6 may include a passage 13 formed by a pipe 12 disposed rearward of the first nozzle 3, a first chamber 26 formed inside a first cylindrical member 20, and a first inlet passage 54 formed by a first inlet pipe 52 connected to the first cylindrical member 20.

[0026] The pipe 12 is disposed so as to extend at least between the front plate 14 and a rear plate 16 disposed rearward of the front plate 14. Further, the ignition rod 10 inside the first nozzle 3 is inserted into the pipe 12. In the illustrated embodiment, the pipe 12 is provided so as to penetrate the rear plate 16. Further, as shown in FIG. 2, a front end portion 12a of the pipe 12 may have a male screw 44, and the pipe 12 may be fastened to the front plate 14 by screwing the end portion 12a into a screw hole 45 formed in the front plate 14.

[0027] Alternatively, the pipe 12 may be connected to the front plate 14 by fitting the front end portion 12a of the pipe 12 into a hole formed in the front plate 14. An oil seal or the like may be installed at the fitting portion.

[0028] Alternatively, as shown in FIG. 8, the pipe 12 and the first nozzle pipe 41 may be integrally formed, and the pipe 12 and the first nozzle pipe 41 may be connected to the front plate 14 by fitting the integrated body of the pipe 12 and the first nozzle pipe 41 into the hole 17 formed in the front plate 14. This allows the ignition rod 10 and the first nozzle pipe 41 to be pulled out of the combustion tube 24 in one piece, making it easy to check the spark condition outside the furnace. Further, when inserting the ignition rod 10 into the pipe 12 and the first nozzle pipe 41, the insulator at the tip of the ignition rod 10 (the insulation tube 11 or a part for centering the ignition rod (not shown)) does not get caught on the step at the connection between the first nozzle pipe 41, the front plate 14, and the pipe 12. As shown in FIG. 8, a seal part 18 (e.g., an oil seal) for reducing gas leakage through a gap between the pipe 12 and first nozzle pipe 41 and the front plate 14 may be provided between the pipe 12 and first nozzle pipe 41 and the front plate 14 in the radial direction of the pipe 12 and first nozzle pipe 41.

[0029] The first cylindrical member 20 is disposed rearward of the rear plate 16 so as to extend along the axial direction. A front end portion of the first cylindrical member 20 may be attached to the rear plate 16. Alternatively, the front end portion of the first cylindrical member 20 may be attached to the rear plate 16 by fitting the pipe 12 to the front end portion of the first cylindrical member 20 and fitting the pipe 12 to the rear plate 16. An opening of a rear end portion of the first cylindrical member 20 may be closed by the ignition plug 9 inserted therein.

[0030] The second gas passage 8 may include a second chamber 28 and a second inlet passage 58. As shown in FIG. 1, the second chamber 28 may be formed by the front plate 14, the rear plate 16, and the inner wall surface of a second cylindrical member 22 extending along the axial direction between the front plate 14 and the rear plate 16. The second inlet passage 58 may be formed by a second inlet pipe 56 connected to the second cylindrical member 22.

[0031] The burner 1 shown in FIG. 1 is attached to a furnace wall 38. The furnace wall 38 may be at least partially formed of a heat insulation material.

[0032] In some embodiments, a hole forming portion of the nozzle plate 30 in which the hole 31 into which the nozzle pipe 40 is fitted is formed includes SiC (silicon carbide) or graphite (carbon graphite), and the tip portions 41a, 42a of the nozzle pipes 40 (41, 42) include an Fe-Cr-Al based alloy. Here, the hole forming portion of the nozzle plate 30 includes the inner wall surface of the hole 31. Further, the tip portions 41a, 42a of the nozzle pipes 40 (41, 42) are portions of the nozzle pipe 40 fitted into the holes 31 of the nozzle plate 30 and located in an extension region of the nozzle plate 30 in the axial direction.

[0033] That is, in some embodiments, the hole forming portion of the nozzle plate 30 is formed of SiC (silicon carbide) or graphite, and the tip portions 41a, 42a of the nozzle pipes 40 (41, 42) are formed of an Fe-Cr-Al based alloy.

[0034] In some embodiments, the entire nozzle plate 30 may be formed of SiC (silicon carbide) or graphite. Alternatively, in some embodiments, the entire nozzle pipes 40 (41, 42) may be formed of an Fe-Cr-Al based alloy.

[0035] The SiC forming the hole forming portion of the nozzle plate 30 may include a normal pressure sintered product or a reaction sintered product.

[0036] The Fe-Cr-Al based alloy forming the tip portions 41a, 42a of the nozzle pipes 40 (41, 42) is an alloy containing 61 wt% or more and 83 wt% or less of iron (Fe), 15 wt% or more and 25 wt% or less of chromium (Cr), and 2 wt% or more and 8 wt% or less of aluminum (Al). The Fe-Cr-Al based alloy may further contain 3 wt% or less of molybdenum (Mo), 1 wt% or less of manganese (Mn), 1 wt% or less of silicon (Si), and / or 1 wt% or less of carbon (C).

[0037] Conventionally, when the nozzle plate becomes hot depending on the operating conditions of the heat treatment facility or the structure of the combustion tube, the nozzle plate and the nozzle pipe fitted into the hole of the nozzle plate may adhere to each other. For example, in the case of a nozzle plate made of SiC and a nozzle pipe made of high Cr-Ni steel, Cr 3 C 2 is likely to be formed by a reaction between SiC and chromium (Cr) contained in the high Cr-Ni steel under high temperature conditions, and the nozzle plate and the nozzle pipe adhere to each other. If the nozzle plate and the nozzle pipe adhere to each other in this way, the heat resistance of the nozzle decreases, which may lead to failure of the burner due to deformation or thinning of the nozzle, or may hinder maintenance.

[0038] In this regard, in the above-described embodiment, since the hole forming portion of the nozzle plate 30 is formed of SiC (silicon carbide) or graphite and the tip portions 41a, 42a of the nozzle pipes 40 (41, 42) are formed of an Fe-Cr-Al based alloy, an aluminum oxide (Al 2 O 3 ) film is formed on the surfaces of the tip portions 41a, 42a of the nozzle pipes 40 (41, 42) when the nozzle plate 30 becomes hot. Since this film prevents the reaction between Cr in the nozzle tip portion and C contained in SiC or graphite, adhesion between the nozzle plate and the nozzle pipe can be suppressed even if the nozzle plate becomes hot.

[0039] In some embodiments, for example, as shown in FIGs. 4 to 6, the combustion tube 24 may have a split structure including a plurality of members connected to each other.

[0040] In the exemplary embodiments shown in FIGs. 4 to 6, the combustion tube 24 includes a base end member 60 surrounding the at least one nozzle pipe 40, and a tip member 62 having the opening portion 25 of the combustion tube 24. The base end member 60 and the tip member 62 are connected to each other at a position on the tip side (that is, a front position) relative to the nozzle plate 30 in the axial direction. The tip member 62 is located forward of the nozzle plate 30.

[0041] In the exemplary embodiments shown in FIGs. 4 to 6, the base end member 60 has an inward flange 61 at a front end portion, and the tip member 62 has an outward flange 63 at a rear end portion. The base end member 60 and the tip member 62 are connected by a surface 61a of the inward flange 61 and a surface 63a of the outward flange 63 abutting against each other.

[0042] When the combustion tube 24 has a split structure including the base end member 60 and the tip member 62, the temperature gradient in each member can be reduced, so that the occurrence of cracks due to thermal stress can be suppressed. However, since the heat of the hotter tip member 62 is less likely to be transferred to the base end member 60, the temperatures of the tip member 62 and the combustion chamber 23 tend to be higher, and the nozzle plate 30 also tends to be higher in temperature. In this regard, in the above-described embodiment, although the combustion tube 24 includes the base end member 60 and the tip member 62 and the nozzle plate 30 is likely to become hot, adhesion between the nozzle plate 30 and the nozzle pipe 40 can be suppressed even if the nozzle plate 30 becomes hot, as described above.

[0043] In some embodiments, as shown in FIGs. 2, 4, and 5, for example, the burner 1 includes a heat insulation material 46 disposed between the combustion tube 24 and the nozzle plate 30.

[0044] In the exemplary embodiment shown in FIG. 2, the heat insulation material 46 is disposed between the inner peripheral surface 24a of the combustion tube 24 and the outer peripheral surface 30a of the nozzle plate 30. In the exemplary embodiment shown in FIG. 4, the heat insulation material 46 is disposed between the rear end surface 62a of the tip member 62 constituting the combustion tube 24 and the front end surface 30b of the nozzle plate 30. In the exemplary embodiment shown in FIG. 5, the heat insulation material 46 is disposed between the inner peripheral surface 60a of the base end member 60 constituting the combustion tube 24 and the outer peripheral surface 30a of the nozzle plate 30, and between the rear end surface 62a of the tip member 62 and the front end surface 30b of the nozzle plate 30.

[0045] According to the above-described embodiment, since the heat insulation material 46 is disposed between the combustion tube 24 and the nozzle plate 30, heat from the combustion tube 24 is less likely to be transferred to the nozzle plate 30. Therefore, even if the combustion tube 24 becomes hot, the nozzle plate 30 can be suppressed from becoming hot. Thus, adhesion between the nozzle plate 30 and the nozzle pipe 40 can be more effectively suppressed.

[0046] As shown in FIGs. 1, 2, and 4 to 6, the combustion tube 24 may include a tapered portion 34 whose diameter gradually decreases from the nozzle plate 30 toward the opening portion 25 of the combustion tube 24 in the axial direction.

[0047] In the exemplary embodiments shown in FIGs. 4 and 5, the tapered portion 34 includes a part of the tip member 62 constituting the combustion tube 24.

[0048] In the exemplary embodiment shown in FIG. 6, the tapered portion 34 includes a first tapered portion 34a which is a part of the tip member 62 constituting the combustion tube 24, and a second tapered portion 34b which is a part of the base end member 60. Each of the first tapered portion 34a and the second tapered portion 34b is shaped such that the diameter gradually decreases from the nozzle plate 30 toward the opening portion 25 of the combustion tube 24 in the axial direction. In this case, the second tapered portion 34b may be disposed within a range where a distance from the nozzle plate 30 in the axial direction is not more than L1 / 2, where L1 (see FIG. 6) is a distance in the axial direction between the nozzle plate 30 and the opening portion 25 of the combustion tube 24. Alternatively, a distance L2 (see FIG. 6) in the axial direction between the nozzle plate 30 and a connection part 64 of the tip member 62 and the base end member 60 may be not more than 1 / 2 of the distance L1.

[0049] In some embodiments, a distance R2 (see FIGs. 2 to 6) in the radial direction between the center of each of the at least one hole 31 of the nozzle plate 30 and the central axis O of the combustion tube 24 is less than 80% of a maximum inner diameter R1 (see FIGs. 2 to 6) of the tapered portion 34 of the combustion tube 24. Alternatively, in some embodiments, each of the at least one hole 31 of the nozzle plate 30 may be provided within a region where a distance from the central axis O in the radial direction is less than 80% of the maximum inner diameter R1 of the tapered portion 34.

[0050] Here, FIG. 7 is a schematic diagram showing a gas flow in the combustion chamber 23. According to the above-described embodiment, since each of the holes 31 of the nozzle plate 30 is located relatively inward in the radial direction, as shown in FIG. 7, a vortex flow F3 is formed by the fuel gas before combustion injected from the nozzle pipe 40 fitted into the hole 31 and the combustion gas in the combustion chamber in a region radially outward of the hole 31 in the combustion chamber 23. This vortex flow F3 is maintained at a relatively low temperature by coming into contact with the nozzle plate 30 having a temperature lower than the temperature of the flame formed in the combustion chamber 23. A part of this relatively low-temperature vortex flow F3 is dragged by the main flow F1 of the gas injected from the nozzle pipe 40 and flows along the inner wall surface of the tapered portion 34, thereby forming a relatively low-temperature gas film F2. This gas film F2 suppresses heat transfer from the high-temperature gas inside the combustion chamber 23 to the combustion tube 24. Therefore, it is possible to more effectively suppress the nozzle plate 30 from becoming hot, whereby adhesion between the nozzle plate 30 and the nozzle pipe 40 can be more effectively suppressed.

[0051] In some embodiments, as shown in FIGs. 1 to 6, for example, the hole 31 of the nozzle plate 30 into which the second nozzle pipe 42 is fitted is disposed on an outer side in the radial direction of the combustion tube 24 relative to the hole 31 of the nozzle plate 30 into which the first nozzle pipe 41 is fitted.

[0052] According to the above-described embodiment, the hole 31 of the nozzle plate 30 into which the first nozzle pipe 41 through which the ignition rod 10 is inserted is fitted is located radially inward of the hole 31 of the nozzle plate 30 into which the second nozzle pipe 42 through which the ignition rod 10 is not inserted is fitted. That is, since the ignition rod 10 is disposed in the vicinity of the central axis O of the combustion tube 24, the flame can be stably maintained. Further, since the ignition rod 10 is disposed in the vicinity of the central axis O of the combustion tube 24 as described above, the temperature distribution in the circumferential direction tends to be uniform. Thus, generation of cracks in the combustion tube 24 and the nozzle plate 30 can be more effectively suppressed.

[0053] In some embodiments, as shown in FIG. 2, for example, a tip 10a of the ignition rod 10 inserted through the first nozzle pipe 41 protrudes toward the opening portion 25 of the combustion tube 24 with respect to the nozzle plate 30.

[0054] Thus, since the tip 10a of the ignition rod 10 protrudes toward the opening portion 25 of the combustion tube 24 with respect to the nozzle plate 30, the flame formed in the combustion chamber 23 can be appropriately detected using the tip portion of the ignition rod 10.

[0055] By exposing the tip portion of the ignition rod 10 to the combustion chamber 23, the tip portion of the ignition rod 10 can function as a detection part of a flame rod (flame detector), and the presence or absence of a flame in the combustion chamber 23 can be detected.

[0056] In the embodiment in which the tip 10a of the ignition rod 10 protrudes toward the opening portion 25 of the combustion tube 24 with respect to the nozzle plate 30 as described above, a distance L3 (see FIG. 2) in the axial direction between the tip 10a of the ignition rod 10 and the nozzle plate 30 may be not less than 3 mm and not more than 20 mm.

[0057] If the distance L3 in the axial direction between the tip 10a of the ignition rod 10 and the nozzle plate 30 is not less than 3 mm, the flame formed in the combustion chamber 23 can be appropriately detected using the tip portion of the ignition rod 10. Further, if the distance in the axial direction between the tip 10a of the ignition rod 10 and the nozzle plate 30 is not more than 20 mm, the ignition rod 10 is not exposed to excessively high temperature. Therefore, according to the above-described embodiment, the flame can be appropriately detected while protecting the ignition rod 10.

[0058] The burner 1 described above can be applied to various heat treatment facilities. A heat treatment facility according to some embodiments includes the above-described burner 1 and a fuel line (not shown) for supplying fuel to the burner 1.

[0059] The heat treatment facility according to an embodiment may be a heat treatment facility for heat-treating a metal plate, and may be, for example, a continuous annealing facility for a metal plate (e.g., a steel plate) or a continuous galvanizing facility for a metal plate (e.g., a steel plate), or a heating furnace included in these facilities.

[0060] In some embodiments, the heat treatment facility for metal plate further includes a conveyance device (not shown) for conveying a metal plate as the object to be treated 101, and the burner 1 is configured to heat the metal plate conveyed by the conveyance device. The metal plate may be a metal strip having a strip shape. In this case, the metal strip may be conveyed continuously by a roller serving as the conveyance device. The burner 1 may continuously heat the metal strip conveyed by the roller.

[0061] The contents described in the above embodiments would be understood as follows, for instance. [1] A burner (1) according to at least one embodiment of the present invention is provided with: a combustion tube (24) forming a combustion chamber (23) for burning a fuel; at least one nozzle pipe (40) for injecting a gas containing the fuel or air into the combustion chamber, the at least one nozzle pipe being disposed inside the combustion tube; and a nozzle plate (30) extending, inside the combustion tube, along a plane perpendicular to an axial direction of the combustion tube, and having at least one hole (31) into which a tip portion of the at least one nozzle pipe is fitted, respectively. A hole forming portion of the nozzle plate in which the at least one hole is formed includes SiC or graphite, and the tip portion of the nozzle pipe includes an Fe-Cr-Al based alloy.

[0062] With the above configuration [1], since the hole forming portion of the nozzle plate is formed of SiC (silicon carbide) or graphite and the tip portion of the nozzle pipe is formed of an Fe-Cr-Al based alloy, an aluminum oxide (Al 2 O 3 ) film is formed on the surface of the tip portion of the nozzle pipe when the nozzle plate becomes hot. Since this film prevents the reaction between Cr in the nozzle tip portion and C contained in SiC or graphite, adhesion between the nozzle plate and the nozzle pipe can be suppressed even if the nozzle plate becomes hot.

[0063] [2] In some embodiments, in the above configuration [1], the combustion tube includes: a base end member (60) surrounding the at least one nozzle pipe; and a tip member (62) having an opening portion (25) of the combustion tube. The base end member and the tip member are connected to each other at a position on a tip side relative to the nozzle plate in the axial direction of the combustion tube.

[0064] When the combustion tube has a split structure including the base end member and the tip member, the temperature gradient in each member can be reduced, so that the occurrence of cracks due to thermal stress can be suppressed. However, since the heat of the hotter tip member is less likely to be transferred to the base end member, the temperatures of the tip member and the combustion chamber tend to be higher, and the nozzle plate also tends to be higher in temperature. In this regard, with the above configuration [2], although the combustion tube includes the base end member and the tip member and the nozzle plate is likely to become hot, adhesion between the nozzle plate and the nozzle pipe can be suppressed even if the nozzle plate becomes hot, as described in [1].

[0065] [3] In some embodiments, in the above configuration [1] or [2], the at least one nozzle pipe includes: a first nozzle pipe (41) through which an ignition rod (10) is inserted; and a second nozzle pipe (42) other than the first nozzle pipe. The hole of the nozzle plate into which the second nozzle pipe is fitted is provided on an outer side in a radial direction of the combustion tube relative to the hole of the nozzle plate into which the first nozzle pipe is fitted.

[0066] With the above configuration [3], the hole of the nozzle plate into which the first nozzle pipe through which the ignition rod is inserted is fitted is located radially inward of the hole of the nozzle plate into which the second nozzle pipe through which the ignition rod is not inserted is fitted. That is, since the ignition rod is disposed in the vicinity of the central axis of the combustion tube, the flame can be stably maintained. Further, since the ignition rod is disposed in the vicinity of the central axis of the combustion tube as described above, the temperature distribution in the circumferential direction tends to be uniform. Thus, generation of cracks in the combustion tube and the nozzle plate can be more effectively suppressed.

[0067] [4] In some embodiments, in any one of the above configurations [1] to [3], the burner is further provided with a heat insulation material (46) disposed between the combustion tube and the nozzle plate.

[0068] With the above configuration [4], since the heat insulation material is disposed between the combustion tube and the nozzle plate, heat from the combustion tube is less likely to be transferred to the nozzle plate. Therefore, even if the combustion tube becomes hot, the nozzle plate can be suppressed from becoming hot. Thus, adhesion between the nozzle plate and the nozzle pipe can be more effectively suppressed.

[0069] [5] In some embodiments, in any one of the above configurations [1] to [4], the combustion tube includes a tapered portion (38) whose diameter gradually decreases from the nozzle plate toward the opening portion of the combustion tube in the axial direction of the combustion tube. A distance R2 in a radial direction between a center of each of the at least one hole of the nozzle plate and a central axis of the combustion tube is less than 80% of a maximum inner diameter R1 of the tapered portion.

[0070] With the above configuration [5], since the hole of the nozzle plate is located relatively inward in the radial direction, a vortex flow is formed by the fuel gas before combustion injected from the nozzle pipe fitted into the hole and the combustion gas in the combustion chamber in a region radially outward of the hole in the combustion chamber. This vortex flow is maintained at a relatively low temperature by coming into contact with the nozzle plate having a temperature lower than the temperature of the flame formed in the combustion chamber. A part of this relatively low-temperature vortex flow is dragged by the main flow of the gas injected from the nozzle pipe and flows along the inner wall surface of the tapered portion, thereby forming a relatively low-temperature gas film. This gas film suppresses heat transfer from the high-temperature gas in the combustion chamber to the combustion tube. Therefore, it is possible to more effectively suppress the nozzle plate from becoming hot, whereby adhesion between the nozzle plate and the nozzle pipe can be more effectively suppressed.

[0071] [6] In some embodiments, in any one of the above configurations [1] to [5], the at least one nozzle pipe includes a first nozzle pipe (41) through which an ignition rod is inserted, and a tip (10a) of the ignition rod protrudes toward the opening portion of the combustion tube with respect to the nozzle plate.

[0072] With the above configuration [6], since the tip of the ignition rod protrudes toward the opening portion of the combustion tube with respect to the nozzle plate, the flame formed in the combustion chamber can be appropriately detected using the tip portion of the ignition rod.

[0073] [7] In some embodiments, in the above configuration [8], the distance (L3) in the axial direction between the tip of the ignition rod and the nozzle plate is not less than 3 mm and not more than 20 mm.

[0074] In the above configuration [7], since the distance in the axial direction between the tip of the ignition rod and the nozzle plate is not less than 3 mm, the flame formed in the combustion chamber can be appropriately detected using the tip portion of the ignition rod. Further, in the above configuration [7], since the distance in the axial direction between the tip of the ignition rod and the nozzle plate is not more than 20 mm, the ignition rod is not exposed to excessively high temperature. Therefore, with the above configuration [7], the flame can be appropriately detected while protecting the ignition rod.

[0075] [8] In some embodiments, in the above configuration [2], the combustion tube includes a tapered portion (34) whose diameter gradually decreases from the nozzle plate toward the opening portion of the combustion tube in the axial direction of the combustion tube. The tapered portion includes: a first tapered portion (34a) formed by the tip member; and a second tapered portion (34b) formed by the base end member.

[0076] With the above configuration [8], even if the burner has a configuration in which the connection position between the base end member and the tip member is located on a relatively tip side such that a part (second tapered portion) of the base end member forms the tapered portion, adhesion between the nozzle plate and the nozzle pipe can be suppressed even if the nozzle plate becomes hot, as described in [1].

[0077] [9] In some embodiments, in the above configuration [8], the second tapered portion is disposed within a range where a distance from the nozzle plate in the axial direction is not more than L1 / 2, where L1 is a distance in the axial direction between the nozzle plate and the opening portion of the combustion tube.

[0078] With the above configuration [9], even if the burner has a configuration in which the connection position between the base end member and the tip member is located on a relatively tip side such that a part (second tapered portion) of the base end member forms the tapered portion, adhesion between the nozzle plate and the nozzle pipe can be suppressed even if the nozzle plate becomes hot, as described in [1].

[0079]

[10] A heat treatment facility according to at least one embodiment of the present invention is provided with: the burner (1) according to any one of [1] to [9] above; and a fuel supply line for supplying a fuel to the burner.

[0080] With the above configuration

[10] , since the hole forming portion of the nozzle plate is formed of SiC (silicon carbide) or graphite and the tip portion of the nozzle pipe is formed of an Fe-Cr-Al based alloy, an aluminum oxide (Al 2 O 3 ) film is formed on the surface of the tip portion of the nozzle pipe when the nozzle plate becomes hot. Therefore, even if the nozzle plate becomes hot, adhesion between the nozzle plate and the nozzle pipe can be suppressed.

[0081] Embodiments of the present invention were described in detail above, but the present invention is not limited thereto, and various amendments and modifications may be implemented.

[0082] In the present specification, an expression of relative or absolute arrangement such as "in a direction", "along a direction", "parallel", "orthogonal", "centered", "concentric" and "coaxial" shall not be construed as indicating only the arrangement in a strict literal sense, but also includes a state where the arrangement is relatively displaced by a tolerance, or by an angle or a distance whereby it is possible to achieve the same function.

[0083] For instance, an expression of an equal state such as "same", "equal", and "uniform" shall not be construed as indicating only the state in which the feature is strictly equal, but also includes a state in which there is a tolerance or a difference that can still achieve the same function.

[0084] Further, an expression of a shape such as a rectangular shape or a cylindrical shape shall not be construed as only the geometrically strict shape but also includes a shape with unevenness or chamfered corners within the range in which the same effect can be achieved.

[0085] On the other hand, an expression such as "comprise", "include", and "have" are not intended to be exclusive of other components.Reference Signs List

[0086] 1Burner 2Combustion nozzle 3First nozzle 3aOutlet 4Second nozzle 4aOutlet 6First gas passage 8Second gas passage 9Ignition plug 10Ignition rod 10aTip 11Insulation tube 12Pipe 12aEnd portion 13Passage 14Front plate 16Rear plate 17Hole 18Seal part 20First cylindrical member 22Second cylindrical member 23Combustion chamber 24Combustion tube 24aInner peripheral surface 25Opening portion 26First chamber 28Second chamber 30Nozzle plate 30aOuter peripheral surface 30bFront end surface 31Hole 34Tapered portion 34aFirst tapered portion 34bSecond tapered portion 36Heat resistant material 38Furnace wall 40Nozzle pipe 41First nozzle pipe 41aTip portion 42Second nozzle pipe 42aTip portion 44Male screw 45Screw hole 46Heat insulation material 52First inlet pipe 54First inlet passage 56Second inlet pipe 58Second inlet passage 60Base end member 60aInner peripheral surface 61Inward flange 61aSurface 62Tip member 62aRear end surface 63Outward flange 63aSurface 64Connection part 101Object to be treated FFlame F1Main flow F2Gas film F3Vortex flow L1Distance L2Distance L3Distance OCentral axis R1Maximum inner diameter R2Distance

Claims

1. A burner, comprising: a combustion tube forming a combustion chamber for burning a fuel; at least one nozzle pipe for injecting a gas containing the fuel or air into the combustion chamber, the at least one nozzle pipe being disposed inside the combustion tube; and a nozzle plate extending, inside the combustion tube, along a plane perpendicular to an axial direction of the combustion tube, and having at least one hole into which a tip portion of the at least one nozzle pipe is fitted, respectively, wherein a hole forming portion of the nozzle plate in which the at least one hole is formed includes SiC or graphite, and wherein the tip portion of the nozzle pipe includes an Fe-Cr-Al based alloy.

2. The burner according to claim 1, wherein the combustion tube includes: a base end member surrounding the at least one nozzle pipe; and a tip member having an opening portion of the combustion tube, and wherein the base end member and the tip member are connected to each other at a position on a tip side relative to the nozzle plate in the axial direction of the combustion tube.

3. The burner according to claim 1 or 2, wherein the at least one nozzle pipe includes: a first nozzle pipe through which an ignition rod is inserted; and a second nozzle pipe other than the first nozzle pipe, and wherein the hole of the nozzle plate into which the second nozzle pipe is fitted is provided on an outer side in a radial direction of the combustion tube relative to the hole of the nozzle plate into which the first nozzle pipe is fitted.

4. The burner according to claim 1 or 2, further comprising a heat insulation material disposed between the combustion tube and the nozzle plate.

5. The burner according to claim 1 or 2, wherein the combustion tube includes a tapered portion whose diameter gradually decreases from the nozzle plate toward the opening portion of the combustion tube in the axial direction of the combustion tube, and wherein a distance R2 in a radial direction between a center of each of the at least one hole of the nozzle plate and a central axis of the combustion tube is less than 80% of a maximum inner diameter R1 of the tapered portion.

6. The burner according to claim 1 or 2, wherein the at least one nozzle pipe includes a first nozzle pipe through which an ignition rod is inserted, and wherein a tip of the ignition rod protrudes toward the opening portion of the combustion tube with respect to the nozzle plate.

7. The burner according to claim 6, wherein the distance in the axial direction between the tip of the ignition rod and the nozzle plate is not less than 3 mm and not more than 20 mm.

8. The burner according to claim 2, wherein the combustion tube includes a tapered portion whose diameter gradually decreases from the nozzle plate toward the opening portion of the combustion tube in the axial direction of the combustion tube, and wherein the tapered portion includes: a first tapered portion formed by the tip member; and a second tapered portion formed by the base end member.

9. The burner according to claim 8, wherein the second tapered portion is disposed within a range where a distance from the nozzle plate in the axial direction is not more than L1 / 2, where L1 is a distance in the axial direction between the nozzle plate and the opening portion of the combustion tube.

10. A heat treatment facility, comprising: the burner according to claim 1 or 2; and a fuel supply line for supplying a fuel to the burner.

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