Burner, heat treatment equipment, and combustion method

Abstract

This burner comprises: a combustion cylinder having a tip opening and forming a combustion chamber for burning fuel; a nozzle member provided inside the combustion cylinder for injecting a mixture of fuel and air into the combustion chamber; and an ignition rod extending inside the combustion cylinder along a central axis of the combustion cylinder. The nozzle member has: a plurality of mixing holes extending along an axial direction of the combustion cylinder and configured to be supplied with air; and a plurality of fuel injection holes for injecting fuel into the plurality of mixing holes, respectively. The burner comprises a deflection part for radially inwardly directing the flow of the mixture injected into the combustion chamber from the plurality of mixing holes.

Description

Burner, heat treatment equipment and combustion method

[0001] The present disclosure relates to a burner, a heat treatment facility, and a combustion method.

[0002] A variety of burners are used to combust the fuel.

[0003] Patent Document 1 describes a pulverized coal fuel burner used in a furnace of a power plant. The burner includes an igniter lance for directly igniting pulverized coal, which is the primary fuel. The igniter lance includes a cylindrical fuel duct and an electric igniter located at the axial center of the fuel duct. A deflector is provided at the end of the fuel duct, and this deflector redirects the flow of pulverized coal fuel exiting the fuel duct through the end toward the plasma (ignition source) formed by the electric igniter.

[0004] Patent No. 6615461

[0005] In heat treatment equipment for heat treating metals and the like, the heat treatment is sometimes carried out using a flame emitted from a combustion tube of a burner. Depending on the state of the flame emitted from the combustion tube, misfires can easily occur or the combustion tube or the like can be easily damaged.

[0006] In view of the above circumstances, an object of at least one embodiment of the present invention is to provide a burner, heat treatment equipment, and combustion method that can suppress misfires and damage to the burner.

[0007] A burner according to at least one embodiment of the present invention comprises: a combustion liner having a tip opening and forming a combustion chamber for burning fuel; a nozzle member provided inside the combustion liner for injecting a mixture of fuel and air into the combustion chamber; and an ignition rod extending inside the combustion liner along the central axis of the combustion liner; wherein the nozzle member has a plurality of mixing holes extending along the axial direction of the combustion liner and configured to receive air, and a plurality of fuel ejection holes for ejecting fuel into each of the plurality of mixing holes; and comprises a deflection section for directing the flow of the mixture of fuel and air ejected from the plurality of mixing holes into the combustion chamber radially inward.

[0008] Furthermore, heat treatment equipment according to at least one embodiment of the present invention includes the burner described above; a fuel supply line for supplying the fuel to the fuel flow path; and an air supply line for supplying the air to the air flow path.

[0009] Furthermore, at least one embodiment of the present invention provides a combustion method for burning fuel using a burner including: a combustion liner having a tip opening and forming a combustion chamber for burning fuel; a nozzle member provided inside the combustion liner for injecting a mixture of fuel and air into the combustion chamber; and an ignition rod extending inside the combustion liner along a central axis of the combustion liner, wherein the nozzle member has: a plurality of mixing holes extending along the axial direction of the combustion liner and configured to receive air; and a plurality of fuel ejection holes for ejecting fuel into each of the plurality of mixing holes, and the method includes the steps of: supplying air to the mixing holes; ejecting fuel into the mixing holes through the fuel ejection holes; redirecting the flow of the mixture of fuel and air ejected from the plurality of mixing holes into the combustion chamber radially inward; and igniting the mixture redirected in the redirecting step using the ignition rod.

[0010] According to at least one embodiment of the present invention, a burner, heat treatment equipment, and combustion method are provided that can suppress misfires and damage to the burner.

[0011] Fig. 2 is a schematic cross-sectional view of a heat treatment facility including a burner according to an embodiment. Fig. 3 is an enlarged view of a front portion of a burner in the heat treatment facility shown in Fig. 1. Fig. 4 is a cross-sectional view of a nozzle member taken along line A-A in Fig. 2. 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.

[0012] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present invention.

[0013] (Configuration of Heat Treatment Equipment and Burner) Fig. 1 is a schematic cross-sectional view of heat treatment equipment 100 including a burner 1 according to one embodiment. Fig. 2 is an enlarged view of the front portion of the burner 1 in the heat treatment equipment shown in Fig. 1, and Fig. 3 is a cross-sectional view of the nozzle member 50 taken along line A-A in Fig. 2. Figs. 4 and 5 are each schematic cross-sectional views of the front portion of a burner according to one embodiment. In this specification, in the axial direction of the burner 1 (or the axial direction of the combustion tube 24), the side where the tip opening 25 of the combustion tube 24 is located is referred to as the front (tip side), and the opposite side is referred to as the rear.

[0014] As shown in FIG. 1 , a heat treatment equipment 100 according to one embodiment includes a burner 1 for heat treating a workpiece S (e.g., a metal plate), a fuel supply line 102 for supplying fuel to the burner 1, and an air supply line 104 for supplying air to the burner 1.

[0015] As shown in Figures 1 to 5, the burner 1 includes a combustion liner 24 that forms a combustion chamber 23, a nozzle member 50 that is provided inside the combustion liner 24 and that sprays a mixture of fuel and air into the combustion chamber 23, and an ignition rod 10 that ignites the mixture sprayed into the combustion chamber 23.

[0016] The combustion liner 24 includes a cylindrical member extending along the axial direction (the direction of the central axis O1 (see FIG. 2 )) and forms a combustion chamber 23 for combusting fuel. Typically, the combustion chamber 23 is at least partially defined by an inner circumferential surface 24 a at the front end of the combustion liner 24 and a front end surface 50 b (see FIG. 2 ) of the nozzle member 50. The combustion chamber 23 is formed at the front end of the combustion liner 24 and communicates with a tip opening 25 of the combustion liner 24.

[0017] In some embodiments, the combustion liner 24 includes a tapered portion 34 whose diameter gradually decreases toward the tip opening 25 in the axial direction of the combustion liner 24. In some embodiments, at least a portion of the combustion chamber 23 may be defined by the tapered portion 34 of the combustion liner 24.

[0018] 2 to 5, the nozzle member 50 is provided inside the combustion liner 24. The nozzle member 50 may include a plate-shaped member having a rear end face 50a and a front end face 50b, which are both axial end faces. The nozzle member 50 has a plurality of mixing holes 52 extending along the axial direction and configured to receive air, and a plurality of fuel ejection holes 54 for ejecting fuel into the plurality of mixing holes 52, respectively. The plurality of fuel ejection holes 54 are supplied with fuel from the fuel flow path 6, and the plurality of mixing holes 52 are supplied with air from the air flow path 8.

[0019] 2 to 5, each of the plurality of mixing holes 52 has an inlet opening 52a that opens to the rear end surface 50a of the nozzle member 50 and an outlet opening 52b that opens to the front end surface 50b of the nozzle member 50. An air flow path 8 is provided behind the nozzle member 50, and air from the air flow path 8 is supplied to each of the plurality of mixing holes 52 via the inlet opening 52a. For example, as shown in FIG. 3, the plurality of mixing holes 52 may be arranged along the circumferential direction of the combustion liner 24.

[0020] Each of the plurality of fuel ejection holes 54 may be supplied with fuel from a fuel flow path 6 provided behind the nozzle member 50. In the exemplary embodiment shown in Figures 2 to 5, a fuel passage 56 is provided inside the nozzle member 50, and fuel from the fuel flow path 6 is supplied to each of the plurality of fuel ejection holes 54 via the fuel passage 56. Each of the plurality of fuel ejection holes 54 may have a first end 54a connected to the fuel passage 56 and a second end 54b connected to the mixing hole 52.

[0021] The fuel passage 56 may be provided to extend inside the nozzle member 50 along the central axis O1 of the combustion tube 24. The fuel passage 56 may have an inlet opening 56a that opens to the rear end surface 50a of the nozzle member 50, and the fuel from the fuel flow path 6 may flow into the fuel passage 56 through the inlet opening 56a. In the illustrated embodiment, the fuel passage 56 has an expanded diameter portion 57 at its front end that has a diameter larger than that of the inlet opening 56a. As illustrated, the first end 54a of the fuel ejection hole 54 may be connected to the expanded diameter portion 57 of the fuel passage 56.

[0022] In the illustrated embodiment, the nozzle member 50 is provided with a hole 58 that opens to the front end face 50b and through which the ignition rod 10 is inserted so as to connect to the fuel passage 56. Because the hole 58 is blocked by the ignition rod 10, fuel from the fuel passage 56 is prevented from flowing out into the combustion chamber 23 through the hole 58.

[0023] The fuel flow passage 6 and / or the air flow passage 8 may be formed by a tubular member.

[0024] 1 to 5 , the fuel flow passage 6 is formed by the inner circumferential surface of the inner pipe 12 that extends axially at least between the nozzle member 50 and the rear plate 16 located rearward of the nozzle member 50. The inner pipe 12 may be provided along the central axis O1 of the combustion liner 24. As shown in the drawings, the inner pipe 12 may be provided so as to penetrate the rear plate 16. Furthermore, as shown in the drawings, the rear end of the inner pipe 12 may be inserted into a tubular member 20 that is connected to the rear surface of the rear plate 16. The rear end of the tubular member 20 may be closed by an ignition plug 9 to which an ignition rod 10 is attached.

[0025] A fuel inlet pipe 42 may be connected to the tubular member 20, and fuel from the fuel supply line 102 may be supplied to the tubular member 20 via the fuel inlet pipe 42 and flow from the tubular member 20 into the fuel flow path 6 (inner pipe 12).

[0026] 1 to 5 , the air flow path 8 includes an annular flow path formed between an outer pipe 22 extending axially radially outside the inner pipe 12 between at least the nozzle member 50 and the rear plate 16 and the outer peripheral surface of the inner pipe 12. The outer pipe 22 may have a front end connected to the nozzle member 50 and a rear end connected to the rear plate 16. The outer pipe 22 may be connected to the combustion liner 24 via a flange portion 14 provided on the outer pipe 22. An air inlet pipe 44 may be connected to the outer pipe 22, and air from an air supply line 104 may be supplied to the air flow path 8 (outer pipe 22) via the air inlet pipe 44.

[0027] The fuel supplied to the burner 1 from the fuel supply line 102 may be gaseous fuel, or may be liquid fuel or solid fuel (such as pulverized coal), or may be a mixture of fuel and gas (for example, a mixture of pulverized coal and air), etc.

[0028] The ignition rod 10 is provided inside the combustion tube 24 so as to extend along the central axis O1 of the combustion tube 24. In the exemplary embodiment shown in FIGS. 1 to 5 , the ignition rod 10 is inserted into an inner tube 12 that forms the fuel flow path 6. The ignition rod 10, except for its tip, may be covered with an insulating tube 11 made of an insulator so as to be insulated from surrounding components. When the burner 1 is ignited, a spark is generated at the tip of the ignition rod 10, igniting the fuel-air mixture ejected into the combustion chamber 23 from the outlet opening 52b of the mixing hole 52 of the nozzle member 50.

[0029] In the burner 1, the fuel in the mixture ejected from the mixing hole 52 burns to generate a flame F, which is ejected from a tip opening 25 formed at the tip of the combustion tube 24. The flame F ejected from the combustion tube 24 in this manner heat-treats the workpiece S (see FIG. 1).

[0030] 1 is attached to a furnace wall 38. The furnace wall 38 may be at least partially formed of a heat insulating material.

[0031] As shown in Figures 1, 2, 4 and 5, the burner 1 is provided with a deflection section 70 for directing the flow of the fuel and air mixture injected into the combustion chamber 23 from the multiple mixing holes 52 radially inward.

[0032] 2 and 4 , the deflection section 70 includes a ring member 72 that is provided inside the combustion liner 24 at a position axially distal (i.e., forward) of the nozzle member 50. The ring member 72 has an inner circumferential surface 72a that slopes toward the central axis O1 of the combustion liner 24 as it approaches the distal end in the axial direction.

[0033] 5 , each of the plurality of mixing holes 52 includes a tip portion 53 (a portion including the outlet opening 52 b) that is inclined such that a center line O2 of the mixing hole 52 approaches the central axis O1 of the combustion liner 24 as it moves toward the tip side in the axial direction of the combustion liner 24. The turning portion 70 includes the tip portion 53 of each of the plurality of mixing holes 52.

[0034] 5, the entirety of each of the multiple mixing holes 52 (from the inlet opening 52a to the outlet opening 52b) is inclined so that the center line O2 approaches the central axis O1 of the combustion tube 24 as it moves toward the tip in the axial direction of the combustion tube 24. In some embodiments, only the tip portion 53 of each of the multiple mixing holes 52 may be inclined as described above.

[0035] In the above-described embodiment, the burner 1 having the combustion tube 24 is provided with the deflection section 70, so that the flow of the fuel-air mixture ejected from the mixing holes 52 of the nozzle member 50 into the combustion chamber 23 can be directed toward the axial center of the combustion tube 24 and collide at the axial center (the position of the central axis O1). Collision of the mixture flow at the axial center promotes mixing of the fuel and air in an area including the axial center, facilitating ignition by the ignition rod 10 located at the axial center. Furthermore, stagnation of the flow is formed near the collision position, suppressing flame lift and improving flame stability. Furthermore, collision of the mixture flow at the axial center improves the symmetry of the flame F (see FIG. 1 ), suppressing uneven temperature distribution in the combustion tube 24. This reduces thermal stress in the combustion tube 24 and suppresses damage to the combustion tube 24. Furthermore, since the temperature distribution in the combustion liner 24 is suppressed, the temperature distribution in the combustion chamber 23 tends to be uniform, which makes it easier for the combustion reaction to occur uniformly, thereby suppressing combustion oscillation and reducing damage to the combustion liner 24 caused by combustion oscillation. Therefore, according to the above-described embodiment, it is possible to suppress damage to the burner 1 while suppressing misfires.

[0036] Furthermore, when the deflection section 70 includes the ring member 72, the ring member 72 is provided forward of the nozzle member 50, so that the ring member 72 can shield the radiant heat from the tip portion of the combustion tube 24, which becomes particularly hot, and can prevent the nozzle member 50 from becoming too hot. This can prevent damage to the nozzle member 50. Therefore, it is possible to more effectively prevent damage to the burner 1 while suppressing misfires in the burner 1.

[0037] In some embodiments, the deflector 70 is located inside the combustion can 24 .

[0038] In some embodiments, the collision position Pc (see FIG. 2, FIG. 4, or FIG. 5) of the mixture ejected from the multiple mixing holes 52 may be located inside the combustion chamber 23. That is, the collision position Pc may be located forward of the nozzle member 50 and rearward of the tip opening 25 of the combustion liner 24. Alternatively, in some embodiments, as shown in FIGS. 2, 4, and 5, for example, the collision position Pc may be located within an extension region of the tapered portion 34 of the combustion liner 24 in the axial direction.

[0039] When the deflection section 70 includes the ring member 72, the collision position Pc may be a point where extension lines of the inner circumferential surfaces 72a of the ring member 72 intersect with each other in a cross section including the central axis O1 of the combustion tube 24 (see FIG. 2 or FIG. 4). When the deflection section 70 includes the tip ends 53 of the mixing holes 52, the collision position Pc may be a point where center lines O2 of the tip ends 53 of the multiple mixing holes 52 intersect with each other in a cross section including the central axis O1 of the combustion tube 24.

[0040] By positioning the collision position Pc inside the combustion chamber 23 or within the extension region of the tapered portion 34, the fuel flows from the multiple mixing holes 52 can be more easily collided at the axial center of the combustion tube 24. Therefore, misfires in the burner 1 can be more effectively suppressed, and damage to the burner 1 can be more effectively suppressed.

[0041] 4 and 5, the center line O3 of each of the fuel ejection holes 54 is inclined toward the tip in the axial direction from the first end 54a to the second end 54b. In some embodiments, the angle θ between the axial direction (the direction of the central axis O1 of the combustion liner 24) and the center line O3 of the fuel ejection hole 54 may be greater than or equal to 45 degrees and less than 90 degrees.

[0042] According to the above-described embodiment, the fuel injection holes 54 are inclined axially toward the tip as they approach the downstream side, which promotes mixing of air and fuel in the mixing holes 52 and suppresses backfire. Therefore, misfires can be more effectively suppressed and damage to the burner 1 can be suppressed.

[0043] In some embodiments, the diameter D2 (see FIG. 3) of the plurality of fuel ejection holes 54 is greater than or equal to 10% and less than or equal to 50% of the diameter D1 (see FIG. 3) of the plurality of mixing holes 52.

[0044] According to the above-described embodiment, the diameter D2 of the fuel ejection hole 54 is 10% or more of the diameter D1 of the mixing hole 52, so that an appropriate amount of fuel can be mixed with the air, and the diameter D2 of the fuel ejection hole 54 is 50% or less of the diameter D1 of the mixing hole 52, so that the fuel can be easily supplied evenly to the plurality of mixing holes 52, and uneven flow of the mixture in the combustion chamber 23 can be suppressed. Therefore, misfires can be more effectively suppressed while damage to the burner 1 can be suppressed.

[0045] In some embodiments, the air passages 8 may be located radially outward of the fuel passages 6, as shown in Figures 1-5.

[0046] According to the above-described embodiment, the air flow path 8 is provided radially outside the fuel flow path 6, making it easy to ensure a sufficient flow path area for the air flow path 8. Furthermore, according to the above-described embodiment, the air flow path 8 is present between the fuel flow path 6 and the high-temperature furnace wall 38, making it possible to prevent the temperature of the fuel supplied to the fuel ejection holes 54 via the fuel flow path 6 from becoming excessively high, thereby reducing the risk of damage to the burner 1 due to ignition of the fuel, etc. Therefore, it is possible to more effectively prevent misfires and damage to the burner 1.

[0047] In some embodiments, for example, as shown in Figures 2, 4 and 5, the tip 10a of the ignition rod 10 may protrude axially further toward the tip side (forward) of the combustion liner 24 than the nozzle member 50.

[0048] In some embodiments, the ratio L1 / L2 of the axial distance L1 (see Figure 2) between the tip 10a of the ignition rod 10 and the front end face 50b of the nozzle member 50 to the outer diameter L2 (see Figure 2) of the ignition rod 10 may be 1.0 or greater and 5.5 or less.

[0049] In the above-described embodiment, the ratio L1 / L2 of the axial distance L1 between the tip 10a of the ignition rod 10 and the front end surface 50b of the nozzle member 50 (i.e., the protrusion amount of the ignition rod 10) to the outer diameter L2 of the ignition rod 10 is 1.0 or greater. This makes ignition less likely to fail and allows for proper flame detection when using a flame rod-type flame detection sensor. Furthermore, in the above-described embodiment, the ratio L1 / L2 is 5.5 or less, making it difficult for the tip portion, including the tip 10a, of the ignition rod 10 to be exposed to high-temperature flames, thereby preventing burnout of the ignition rod 10. Therefore, according to the above-described embodiment, misfires can be more effectively prevented and damage to the burner 1 can be more effectively prevented.

[0050] In some embodiments, for example, as shown in Figures 2 and 3, the tip 10a of the ignition rod 10 may protrude axially further toward the tip (forward) of the combustion tube 24 than the ring member 72 serving as the deflection portion 70.

[0051] In the above-described embodiment, the tip 10a of the ignition rod 10 protrudes further toward the tip (forward) of the combustion tube 24 than the ring member 72, making it less likely for ignition to fail and enabling proper flame detection when a flame rod-type flame detection sensor is used. Therefore, according to the above-described embodiment, misfires can be more effectively suppressed and damage to the burner 1 can be suppressed.

[0052] 2 and 4 , the combustion tube 24 may have a divided structure including a base end member 60 that surrounds the nozzle member 50 and a tip end member 62 that has the tip opening 25 of the combustion tube 24. The base end member 60 and the tip end member 62 may be connected to each other at a connecting portion 64. The base end member 60 and the tip end member 62 may be connected to each other at a position that is further tipward than the nozzle member 50 in the axial direction of the combustion tube 24.

[0053] According to the above-described embodiment, the combustion tube 24 has a divided structure including the base end member 60 that surrounds the nozzle member 50 and the tip end member 62 that has the tip opening 25 of the combustion tube 24, and therefore the temperature gradient in each member (the base end member 60 and the tip end member 62) can be reduced, thereby suppressing the occurrence of cracks due to thermal stress in the combustion tube 24. Therefore, according to the above-described embodiment, it is possible to more effectively suppress damage to the burner 1 while suppressing misfires.

[0054] 2 and 4, the base member 60 has an inward flange at its front end, and the tip member 62 has an outward flange at its rear end. The base member 60 and the tip member 62 are connected by the inward flange of the base member 60 abutting against the outward flange of the tip member 62.

[0055] In some embodiments, as shown in Figures 1, 2, 4, and 5, the burner 1 may include a suction hole 80 provided in the combustion liner 24 to connect the outer space of the combustion liner 24 with the combustion chamber 23. The combustion liner 24 may be provided with a plurality of suction holes 80. The plurality of suction holes 80 may be arranged in the circumferential direction.

[0056] The suction hole 80 is provided axially forward of the nozzle member 50 and as far rearward as possible. The suction hole 80 may be provided rearward of the tapered portion 34 of the combustion tube 24, as shown in Figures 2, 4, and 5, for example. The suction hole 80 may be provided rearward of the tip 10a of the ignition rod 10, as shown in Figure 5, for example.

[0057] According to the above-described embodiment, the combustion liner 24 is provided with a suction hole 80 that connects the outer space of the combustion liner 24 with the combustion chamber 23 inside the combustion liner 24. Therefore, combustion gas (gas generated by fuel combustion) in the outer space of the combustion liner 24 is drawn into the combustion chamber 23 through the suction hole 80. This combustion gas has a lower temperature and a lower oxygen concentration than the gas inside the combustion chamber 23. Therefore, the combustion liner 24 is cooled as the combustion gas is drawn into the combustion chamber 23 and flows along the inner wall surface of the combustion liner 24 toward the tip opening 25. This cools the combustion liner 24 and moves the fuel combustion start position (or flame formation position) further forward. This makes it easier for the high-temperature portion of the flame to be located outside the combustion liner 24, thereby reducing the thermal load on the combustion liner 24. Furthermore, since the flame is positioned further forward, the heating efficiency of the workpiece S is improved. Furthermore, the reduced oxygen concentration inside the combustion chamber 23 slows the fuel combustion rate, thereby reducing the nitrogen oxide (NOx) concentration in the exhaust gas. Therefore, according to the above-described embodiment, it is possible to more effectively prevent damage to the burner 1 while suppressing misfires, and more efficient heat treatment is possible, or nitrogen oxide emissions can be reduced.

[0058] The contents described in each of the above embodiments can be understood, for example, as follows.

[0059] [1] A burner (1) according to at least one embodiment of the present invention comprises: a combustion liner (24) having a tip opening (25) and forming a combustion chamber (23) for burning fuel; a nozzle member (50) provided inside the combustion liner for injecting a mixture of fuel and air into the combustion chamber; and an ignition rod (10) extending inside the combustion liner along a central axis (O1) of the combustion liner, wherein the nozzle member has: a plurality of mixing holes (52) extending along the axial direction of the combustion liner and configured to receive air; and a plurality of fuel ejection holes (54) for ejecting fuel into each of the plurality of mixing holes; and a deflection section (70) for directing the flow of the mixture of fuel and air ejected from the plurality of mixing holes into the combustion chamber radially inward.

[0060] According to the configuration [1] above, a deflection section is provided in the burner having a combustion chamber, so that the flow of the fuel-air mixture ejected from the mixing hole of the nozzle member into the combustion chamber can be directed toward the axial center of the combustion chamber and collide at the axial center. Collision of the mixture flow at the axial center promotes mixing of the fuel and air in an area including the axial center, facilitating ignition by the ignition rod located at the axial center. Furthermore, stagnation of the flow forms near the collision position, suppressing flame lift and improving flame stability. Furthermore, collision of the mixture flow at the axial center improves flame symmetry, suppressing uneven temperature distribution in the combustion chamber, thereby reducing thermal stress in the combustion chamber and suppressing damage to the combustion chamber. Furthermore, suppressing uneven temperature distribution in the combustion chamber also facilitates uniform temperature distribution in the combustion chamber, thereby suppressing combustion oscillation and suppressing damage to the combustion chamber due to combustion oscillation. Therefore, the configuration [1] above can suppress misfires and damage to the burner.

[0061] [2] In some embodiments, in the configuration of [1] above, the deflection portion includes a ring member (72) provided inside the combustion tube at a position further forward than the nozzle member in the axial direction, and the ring member has an inner peripheral surface (72a) that slopes toward the central axis as it approaches the forward end in the axial direction.

[0062] The configuration [2] above allows for the burner including the deflection section of the configuration [1] to be realized with a simple configuration using a ring member having an inner circumferential surface that slopes toward the central axis of the combustion liner as it approaches the tip in the axial direction. Furthermore, the configuration [2] above allows for the ring member to be positioned forward of the nozzle member, thereby blocking radiant heat from the tip of the combustion liner, which becomes particularly hot, and thus preventing the nozzle member from becoming too hot. This prevents damage to the nozzle member. Therefore, the configuration [2] above allows for a simple configuration that effectively prevents burner damage while suppressing misfires.

[0063] [3] In some embodiments, in the configuration of [1] above, each of the plurality of mixing holes includes a tip portion (53) whose center line is inclined so as to approach the central axis as it moves toward the tip side in the axial direction, and the turning portion includes the tip portion of each of the plurality of mixing holes.

[0064] In the configuration [3] above, a burner including the deflection section of [1] above can be realized with a simple configuration in which at least the tip ends of the multiple mixing holes provided in the nozzle member are inclined. Therefore, with the configuration [3] above, it is possible to suppress misfires and damage to the burner with a simple configuration.

[0065] [4] In some embodiments, in the configuration of any one of [1] to [3] above, the nozzle member has a fuel passage (56) extending along the axial direction and configured to receive the fuel, and each of the plurality of fuel ejection holes has a first end (54a) connected to the fuel passage and a second end (54b) connected to one of the plurality of mixing holes.

[0066] According to the configuration [4] above, the fuel in the fuel passage can be ejected into the mixing hole through the fuel ejection hole that connects the fuel passage extending along the axial direction to the mixing hole. This allows the fuel to be appropriately mixed with the air flowing through the mixing hole. Therefore, it is possible to more effectively suppress misfires and damage to the burner.

[0067] [5] In some embodiments, in the configuration of [4] above, the center line (O3) of each of the plurality of fuel ejection holes is inclined toward the tip side in the axial direction as it approaches the second end from the first end.

[0068] According to the configuration [5] above, the fuel injection holes are inclined axially toward the tip as they approach the downstream side, which promotes mixing of air and fuel in the mixing holes and suppresses flashback, thereby more effectively suppressing misfires and reducing damage to the burner.

[0069] [6] In some embodiments, in the configuration of any one of [1] to [5] above, the diameter (D2) of the plurality of fuel injection holes is 10% or more and 50% or less of the diameter (D1) of the plurality of mixing holes.

[0070] According to the configuration [6] above, since the diameter of the fuel injection hole is 10% or more of the diameter of the mixing hole, an appropriate amount of fuel can be mixed into the air, and since the diameter of the fuel injection hole is 50% or less of the diameter of the mixing hole, it is easy to supply fuel evenly to the multiple mixing holes, and it is possible to suppress uneven flow of the mixture in the combustion chamber 23. Therefore, it is possible to more effectively suppress misfires and damage to the burner.

[0071] [7] In some embodiments, in any of the configurations [1] to [6] above, the burner comprises: a fuel flow path (6) extending inside the combustion tube along the axial direction and for supplying the fuel to the fuel ejection holes; and an air flow path (8) extending inside the combustion tube along the axial direction and for supplying the air to the mixing holes, and the air flow path is provided radially outside the fuel flow path.

[0072] According to the configuration [7] above, since the air flow path is provided radially outside the fuel passage, it is easy to ensure the flow area of ​​the air flow path. Furthermore, according to the configuration [7] above, since the air flow path is located between the fuel flow path and the high-temperature furnace wall, it is possible to prevent the temperature of the fuel supplied to the fuel injection holes through the fuel passage from becoming excessively high, and it is possible to reduce the risk of damage to the burner due to ignition of the fuel, etc. Therefore, it is possible to more effectively prevent misfires and damage to the burner.

[0073] [8] In some embodiments, in any of the configurations [1] to [7] above, the tip of the ignition rod protrudes further toward the tip of the combustion tube in the axial direction than the nozzle member, and the ratio L1 / L2 of the distance L1 in the axial direction between the tip of the ignition rod and the front end face (50a) of the nozzle member to the outer diameter L2 of the ignition rod is 1.0 or more and 5.5 or less.

[0074] In the configuration [8] above, the ratio L1 / L2 of the axial distance L1 between the tip of the ignition rod and the front end face of the nozzle member (i.e., the amount of protrusion of the ignition rod) to the outer diameter L2 of the ignition rod is 1.0 or greater, making ignition less likely to fail and enabling proper flame detection when using a flame rod-type flame detection sensor. Furthermore, in the configuration [8] above, the ratio L1 / L2 is 5.5 or less, making it less likely that the tip of the ignition rod will be exposed to high-temperature flames, thereby preventing burnout of the ignition rod. Therefore, the configuration [8] above can more effectively prevent misfires and more effectively prevent damage to the burner.

[0075] [9] In some embodiments, in any of the configurations [1] to [8] above, the combustion tube includes a base end member (60) surrounding the nozzle member, and a tip end member (62) having the tip opening of the combustion tube, and the base end member and the tip end member are connected to each other at a position further tip than the nozzle member in the axial direction of the combustion tube.

[0076] In the configuration [9] above, the combustion tube has a divided structure including a base end member that surrounds the nozzle member and a tip end member that has a tip opening of the combustion tube, so that the temperature gradient in each member (base end member and tip end member) can be reduced, and therefore the occurrence of cracks due to thermal stress in the combustion tube can be suppressed. Therefore, with the configuration [9] above, it is possible to more effectively suppress damage to the burner while suppressing misfires.

[0077]

[10] In some embodiments, in any of the configurations [1] to [9] above, the burner is provided in the combustion tube and has a suction hole (80) that connects the outer space of the combustion tube with the combustion chamber.

[0078] According to the configuration of

[10] above, the combustion chamber is provided with a suction hole that connects the outer space of the combustion chamber with the combustion chamber inside the combustion chamber. Therefore, combustion gas (gas generated by fuel combustion) in the outer space of the combustion chamber is drawn into the combustion chamber through the suction hole. This combustion gas has a lower temperature and oxygen concentration than the gas inside the combustion chamber. Therefore, the combustion chamber is cooled by the combustion gas being drawn into the combustion chamber and flowing along the inner wall surface of the combustion chamber toward the tip opening. This not only cools the combustion chamber, but also moves the fuel combustion start position (or flame formation position) further forward, making it easier for the high-temperature part of the flame to be located outside the combustion chamber, thereby reducing the thermal load on the combustion chamber. Furthermore, since the flame is positioned further forward, the heating efficiency of the workpiece is improved. Furthermore, the reduced oxygen concentration inside the combustion chamber slows the fuel combustion rate, thereby reducing the nitrogen oxide (NOx) concentration in the exhaust gas. Therefore, according to the configuration

[10] above, it is possible to more effectively prevent damage to the burner while suppressing misfires, and also to enable more efficient heat treatment, or to reduce nitrogen oxide emissions.

[0079]

[11] A heat treatment facility (100) according to at least one embodiment of the present invention comprises: a burner (1) according to any one of [1] to

[10] above; a fuel supply line (102) for supplying the fuel to the burner; and an air supply line (104) for supplying the air to the burner.

[0080] According to the configuration of

[11] above, a deflection section is provided in the burner having a combustion chamber, so that the flow of the fuel-air mixture ejected from the mixing hole of the nozzle member into the combustion chamber can be directed toward the axial center of the combustion chamber and collide at the axial center. Collision of the mixture flow at the axial center promotes mixing of the fuel and air in an area including the axial center, facilitating ignition by the ignition rod located at the axial center. Furthermore, stagnation of the flow forms near the collision position, suppressing flame lift and improving flame stability. Furthermore, collision of the mixture flow at the axial center improves flame symmetry, suppressing uneven temperature distribution in the combustion chamber, thereby reducing thermal stress in the combustion chamber and suppressing damage to the combustion chamber. Furthermore, suppressing uneven temperature distribution in the combustion chamber also facilitates uniform temperature distribution in the combustion chamber, thereby suppressing combustion oscillation and suppressing damage to the combustion chamber due to combustion oscillation. Therefore, the configuration of

[11] above can suppress misfires and damage to the burner.

[0081]

[12] At least one embodiment of the present invention provides a combustion method using a burner (1) including: a combustion liner (24) having a tip opening (25) and forming a combustion chamber (23) for burning fuel; a nozzle member (50) provided inside the combustion liner for injecting a mixture of fuel and air into the combustion chamber; and an ignition rod (10) extending inside the combustion liner along a central axis (O1) of the combustion liner, wherein the nozzle member has a plurality of mixing holes (52) extending along the axial direction of the combustion liner and configured to receive air; and a plurality of fuel ejection holes (54) for ejecting fuel into each of the plurality of mixing holes, the method comprising the steps of: supplying air to the mixing holes; ejecting fuel into the mixing holes through the fuel ejection holes; redirecting the flow of the mixture of fuel and air ejected from the plurality of mixing holes into the combustion chamber radially inward; and igniting the mixture redirected in the redirecting step using the ignition rod.

[0082] According to the method of

[12] , a deflection section is provided in a burner having a combustion chamber, so that the flow of the fuel-air mixture ejected from the mixing hole of the nozzle member into the combustion chamber can be directed toward the axial center of the combustion chamber and collide at the axial center. Collision of the mixture flow at the axial center promotes mixing of the fuel and air in an area including the axial center, facilitating ignition by the ignition rod located at the axial center. Furthermore, stagnation of the flow forms near the collision position, suppressing flame lift and improving flame stability. Furthermore, collision of the mixture flow at the axial center improves flame symmetry, suppressing uneven temperature distribution in the combustion chamber, thereby reducing thermal stress in the combustion chamber and suppressing damage to the combustion chamber. Furthermore, suppressing uneven temperature distribution in the combustion chamber also facilitates uniform temperature distribution in the combustion chamber, thereby suppressing combustion oscillation and suppressing damage to the combustion chamber due to combustion oscillation. Therefore, the method of

[12] can suppress misfires and damage to the burner.

[0083] The above describes an embodiment of the present invention, but the present invention is not limited to the above-described embodiment, and also includes forms in which the above-described embodiment is modified, or forms in which these forms are appropriately combined.

[0084] In this specification, expressions expressing relative or absolute arrangements, such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," not only strictly express such arrangements, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions expressing that things are in an equal state, such as "identical," "equal," and "homogeneous," not only express a state in which there is a strict equivalence, but also express a state in which there is a tolerance or a difference to the extent that the same function is obtained. Furthermore, in this specification, expressions expressing shapes such as a rectangular shape or a cylindrical shape not only express shapes such as a rectangular shape or a cylindrical shape in the strict geometric sense, but also express shapes including concave and convex portions, chamfered portions, etc., to the extent that the same effect is obtained. Furthermore, in this specification, the expressions "comprise," "include," or "have" a component are not exclusive expressions that exclude the presence of other components.

[0085] REFERENCE SIGNS LIST 1 burner 6 fuel flow path 8 air flow path 9 ignition plug 10 ignition rod 10a tip 11 insulating tube 12 inner tube 14 flange portion 16 rear plate 20 tubular member 22 outer tube 23 combustion chamber 24 combustion liner 24a inner circumferential surface 25 tip opening 34 tapered portion 38 furnace wall 42 fuel inlet tube 44 air inlet tube 50 nozzle member 50a rear end surface 50b front end surface 52 mixing hole 52a inlet opening 52b outlet opening 53 tip portion 54 fuel ejection hole 54a first end 54b second end 56 fuel passage 56a inlet opening 57 enlarged diameter portion 58 hole 60 base end member 62 tip member 64 connection portion 70 deflection portion 72 Ring member 72a: Inner peripheral surface 80: Suction hole 100: Heat treatment equipment 102: Fuel supply line 104: Air supply line F: Flame L1: Distance L2: Outer diameter O1: Central axis O2: Center line O3: Center line Pc: Collision position S: Workpiece θ: Angle

Claims

1. A burner comprising: a combustion tube having a tip opening and forming a combustion chamber for burning fuel; a nozzle member provided inside the combustion tube for injecting a mixture of fuel and air into the combustion chamber; and an ignition rod extending inside the combustion tube along the central axis of the combustion tube, wherein the nozzle member has a plurality of mixing holes extending along the axial direction of the combustion tube and configured to receive air, and a plurality of fuel ejection holes for ejecting fuel into each of the plurality of mixing holes; and a deflection section for directing the flow of the mixture of fuel and air ejected from the plurality of mixing holes into the combustion chamber radially inward.

2. A burner as described in claim 1, wherein the deflection section includes a ring member provided inside the combustion tube at a position closer to the tip of the nozzle member in the axial direction, and the ring member has an inner circumferential surface that slopes toward the central axis as it moves toward the tip in the axial direction.

3. A burner as described in claim 1, wherein each of the plurality of mixing holes includes a tip portion whose centerline is inclined so as to approach the central axis as it moves toward the tip side in the axial direction, and the turning portion includes the tip portion of each of the plurality of mixing holes.

4. A burner as claimed in any one of claims 1 to 3, wherein the nozzle member has a fuel passage extending along the axial direction and configured to receive the fuel, and each of the plurality of fuel ejection holes has a first end connected to the fuel passage and a second end connected to one of the plurality of mixing holes.

5. A burner according to claim 4, wherein the center line of each of the plurality of fuel injection holes is inclined toward the tip side in the axial direction as it approaches the second end from the first end.

6. A burner according to any one of claims 1 to 3, wherein the diameter of the plurality of fuel injection holes is 10% to 50% of the diameter of the plurality of mixing holes.

7. A burner as claimed in any one of claims 1 to 3, comprising: a fuel flow path extending inside the combustion tube along the axial direction and for supplying the fuel to the fuel ejection holes; and an air flow path extending inside the combustion tube along the axial direction and for supplying the air to the mixing holes, wherein the air flow path is provided radially outside the fuel flow path.

8. A burner as claimed in any one of claims 1 to 3, wherein the tip of the ignition rod protrudes further towards the tip of the combustion tube in the axial direction than the nozzle member, and the ratio L1 / L2 of the distance L1 in the axial direction between the tip of the ignition rod and the front end face of the nozzle member to the outer diameter L2 of the ignition rod is 1.0 or more and 5.5 or less.

9. A burner as claimed in any one of claims 1 to 3, wherein the combustion tube includes a base end member surrounding the nozzle member and a tip end member having the tip opening of the combustion tube, and the base end member and the tip end member are connected to each other at a position further tip than the nozzle member in the axial direction of the combustion tube.

10. A burner according to any one of claims 1 to 3, comprising a suction hole provided in the combustion tube to connect the outer space of the combustion tube with the combustion chamber.

11. A heat treatment facility comprising: a burner according to any one of claims 1 to 3; a fuel supply line for supplying the fuel to the burner; and an air supply line for supplying the air to the burner.

12. A method for burning fuel using a burner including: a combustion tube having a tip opening and forming a combustion chamber for burning fuel; a nozzle member provided inside the combustion tube for spraying a mixture of fuel and air into the combustion chamber; and an ignition rod extending inside the combustion tube along the central axis of the combustion tube, wherein the nozzle member has a plurality of mixing holes extending along the axial direction of the combustion tube and configured to receive air; and a plurality of fuel ejection holes for ejecting fuel into each of the plurality of mixing holes, the method comprising the steps of: supplying air to the mixing holes; ejecting fuel into the mixing holes through the fuel ejection holes; redirecting the flow of the mixture of fuel and air ejected from the plurality of mixing holes into the combustion chamber radially inward; and igniting the mixture redirected in the redirecting step using the ignition rod.

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