Burner efficiency improvement attachment parts and their attachment structure

Abstract

To reduce short pass of combustion air toward an exhaust gas side to improve burner efficiency of a single-type heat storage burner.SOLUTION: With respect to a single-type heat storage burner 1 including a cylindrical fuel discharge portion 13 protruding forward from a central portion of an intake / exhaust air surface and the intake / exhaust air surface 11 provided with an intake / exhaust air port 12, a fitting 3 is used in a state in which it has its axis oriented in the same direction as an axis of the fuel discharge portion 13, an inner diameter surface is made to face an outer diameter surface of the fuel discharge portion 13 with a space in between, and one end opening portion is made to face the intake / exhaust air surface 11 with a space in between. Being a cylindrical component with a minimum inner diameter larger than an outer diameter of the cylindrical fuel discharge portion 13, the cylindrical fitting 3 has: a reduced diameter portion 31 with an inner diameter narrowed down to a small diameter in a midway portion in an axial direction; and a first enlarged diameter portion 32 being a portion on the one end opening portion side than the reduced diameter portion 31, and having an inner diameter increasing toward an opening end of the one end opening portion as it approaches the opening end.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a mounting component and mounting structure for use with a single-type regenerative combustion burner to improve burner efficiency, and more particularly to a technique suitable for use with a single-type regenerative combustion burner in a radiant tube furnace. [Background technology]

[0002] The single-type regenerative combustion burner comprises a single burner body, a regenerator with multiple intake and exhaust passages, and an intake and exhaust switching valve. The single-type regenerative combustion burner exchanges heat between the intake and exhaust by alternately supplying combustion air (intake air) and exhausting exhaust gas (exhaust) through the regenerator. This allows the single-type regenerative combustion burner to preheat the intake air (combustion air) and lower the exhaust gas temperature, thereby improving thermal efficiency. Such single-type regenerative combustion burners are used, for example, in radiant tube furnaces.

[0003] Here, the prior art discloses a cylindrical part for a single-type regenerative combustion burner used in a radiant tube furnace. The cylindrical part is an attachment part for improving burner efficiency by forming a combustion air discharge passage on the outer periphery of a cylindrical fuel discharge part protruding from the center of the intake and exhaust surface.

[0004] For example, Patent Document 1 describes a cylindrical pressure loss piece that is provided around the fuel discharge part of a single-type regenerative combustion burner and forms a combustion air discharge passage outside the fuel discharge part. This pressure loss piece has a header (tapered part) formed in the upstream part of the combustion air discharge passage and a narrowed part (straight cylindrical part) downstream of the header. The pressure loss piece also has two or more exhaust inlets opening on the side parts near the supply and exhaust ports of the regenerative burner. Patent Document 1 discloses that the pressure loss piece allows both intake and exhaust at the supply and exhaust ports and prevents the fuel gas from short-passing to the supply and exhaust port on the exhaust side.

[0005] Patent Document 2 also describes the provision of a first throttle member for throttling the combustion air supplied around the fuel discharge portion of the single-type regenerative combustion burner, and a funnel-shaped second throttle member for throttling the combustion air discharged from the intake and exhaust port around the intake and exhaust port of the burner upstream of the first throttle member. Patent Document 2 also discloses a technology in which exhaust gas is introduced between the first and second throttle members and around the outer periphery of the first throttle member. Patent Document 2 also discloses that the combination of the first and second throttle members makes it possible to increase the amount of exhaust gas recirculation and reduce the generation of NOx. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2003-130338 A [Patent Document 2] JP 2004-132574 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the annular pressure loss piece described in Patent Document 1 has a problem in that a large amount of combustion air short passes to the intake and exhaust port on the exhaust side. The reason for this is as follows. When a pressure loss piece is used, the flow path from the exhaust outlet to the intake and exhaust port formed by the pressure loss piece is narrow. Therefore, exhaust gas cannot be sufficiently sucked from the exhaust outlet to the intake and exhaust port, so there is a risk that the amount of short-pass combustion air will increase relatively. Furthermore, the combination of the first throttle member and the funnel-shaped second throttle member described in Patent Document 2 suppresses short-passing of the supplied fuel gas to the burner side and increases the exhaust gas recirculation rate. Therefore, the combination of the first throttle member and the second throttle member encourages the exhaust gas to flow in the direction of the fuel discharge port, and does not improve the short-passing of the combustion air.

[0008] Here, when the combustion air is short-passed as described above, the heat used for preheating is discharged without contributing to combustion, resulting in a decrease in the amount of recovered heat and an increase in the amount of fuel. Also, in all of the above conventional technologies, when the flow path of the combustion air is bent by the attachment parts, a vortex is generated in the flow of the combustion air, and a part of the combustion air flows back to the exhaust side.

[0009] The present invention has been made in consideration of the above-mentioned points, and aims to provide an attachment part that can reduce the short path of combustion air to the exhaust side and improve the burner efficiency of a single-type regenerative combustion burner. [Means for solving the problem]

[0010] In order to solve the problem, one aspect of the present invention provides an attachment part for a single-type regenerative combustion burner having an intake and exhaust surface with multiple intake and exhaust ports opening therein, and a cylindrical fuel discharge part protruding forward from the center of the intake and exhaust surface, which is arranged on the outer periphery of the fuel discharge part to improve burner efficiency, wherein the attachment part is a cylindrical part whose minimum inner diameter is larger than the outer diameter of the cylindrical fuel discharge part and is used with its axis oriented in the same direction as the axis of the fuel discharge part, with its inner diameter surface facing the outer diameter surface of the fuel discharge part with a gap and with one end opening facing the intake and exhaust surface with a gap, and the cylindrical attachment part has a reduced diameter section whose inner diameter is narrowed to a small diameter in the middle part in the axial direction, and an expanded diameter section which is on the one end opening side than the reduced diameter section and has an inner diameter which becomes larger the closer it is to the open end of the one end opening. Effect of the Invention

[0011] When the mounting part according to the present invention is disposed on the outer periphery of the fuel discharge part of a single-type regenerative combustion burner, a combustion air discharge passage is formed between the inner diameter surface of the cylindrical mounting part and the outer diameter surface of the fuel discharge part. At this time, the flow of combustion air, which is the intake air flow from the intake and exhaust port formed on the intake and exhaust surface, is narrowed by the expanded diameter section, so that the combustion air spreads in the circumferential direction in the combustion air discharge passage. Furthermore, the flow of combustion air is narrowed by the reduced diameter section at a position downstream of the expanded diameter section, so that the flow rate of the combustion air in the combustion air discharge passage is increased and the combustion air is spread further around the entire circumference of the fuel gas discharge part.

[0012] According to this aspect of the present invention, the flow velocity of the combustion air is increased by throttling at the reduced diameter section, thereby preventing short-pass of the combustion air due to backflow of the combustion air in the combustion air discharge passage. In addition, by separating the attachment part of the present invention for throttling the combustion air from the burner body and forming a gap, there is no barrier when the exhaust gas is sucked into the intake and exhaust port of the burner, and the exhaust of the exhaust gas to the intake and exhaust port on the exhaust side is promoted. As a result, the combustion air discharged from the intake and exhaust port on the intake side is relatively less likely to be sucked into the intake and exhaust port on the exhaust side, and the amount of short-pass combustion air to the intake and exhaust port on the exhaust side is reduced.

[0013] As described above, according to the aspects of the present invention, it is possible to reduce the short pass of combustion air to the exhaust side and improve the burner efficiency of a single-type regenerative combustion burner. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram of an embodiment of a radiant tube burner according to the present invention. [Diagram 2] FIG. 2 is a diagram showing the dimensions of each part of the mounting parts for improving burner efficiency. [Diagram 3] FIG. 13 is a schematic diagram of the gas flow when the lower intake and exhaust port is for exhaust. [Figure 4] FIG. 13 is a schematic diagram of the gas flow when the upper air intake and exhaust port is for exhaust. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Next, an embodiment of the present invention will be described with reference to the drawings. In the following description, a single-type regenerative combustion burner equipped with burner efficiency improving attachment parts is used as a radiant tube burner. (Single type regenerative combustion burner 1) The single-type regenerative combustion burner 1 shown in FIG. 1 includes a cylindrical fuel discharge section 13 and a plurality of regenerative bodies 10. The fuel discharge section 13 protrudes forward from the center of the intake and exhaust surface 11, and discharges fuel gas and pilot air from a fuel discharge port 13a at the tip of the fuel discharge section 13. Each regenerative body 10 has an intake and exhaust port 12 on the intake and exhaust surface 11. The intake and exhaust ports 12 opening on the intake and exhaust surface 11 are arranged along the circumference of the same circle centered on the center of the intake and exhaust surface 11. The single-type regenerative combustion burner 1 exchanges heat in the regenerative body 10 by alternately supplying combustion air and exhausting exhaust gas through each regenerative body 10 using the intake and exhaust switching valve 14. Therefore, the intake and exhaust ports 12 alternate while continuously switching between intake and exhaust, and the intake and exhaust are performed on the intake and exhaust surface 11.

[0016] (Burner efficiency improvement attachment parts 3) The burner efficiency improving attachment part 3 of this embodiment is a part for improving the burner efficiency, which is disposed on the outer periphery of the fuel discharge part 13. As shown in FIG. 1, the burner efficiency improving attachment part 3 is a cylindrical part whose minimum inner diameter is larger than the outer diameter of the fuel discharge part 13. The burner efficiency improving attachment part 3 is attached with its axis facing in the same direction as the axis of the fuel discharge part 13 (coaxial in this example), as shown in Figure 1, with its inner diameter surface facing the outer diameter surface of the fuel discharge part 13 with a gap, and with one end opening (the right end side in Figure 1) facing the air intake and exhaust surface 11 with a gap. As shown in FIG. 1, the burner efficiency improving attachment part 3 includes a reduced diameter portion 31, and a first enlarged diameter portion 32 and a second enlarged diameter portion 33 that constitute an enlarged diameter portion.

[0017] <Reduced diameter part 31> The reduced diameter portion 31 is a portion formed in the middle in the axial direction, where the inside diameter is narrowed to a small diameter. Here, the distance (radial gap) between the outer surface of the fuel discharge portion 13 and the inner surface of the reduced diameter portion 31 is preferably 20 mm or more and 200 mm or less. If the distance is too small, the required flow rate of the combustion air cannot be ensured.

[0018] <First enlarged diameter part (enlarged diameter part) 32> The first enlarged diameter section 32 is a section closer to the one end opening side (the intake / exhaust surface 11 side) than the reduced diameter section 31, and the inner diameter becomes larger toward the opening end of the one end opening. The first enlarged diameter section 32 of this embodiment is in communication with the reduced diameter section 31, and has a truncated cone shape with an inner diameter surface that is tapered at a predetermined inclination angle all around the circumferential direction. A straight cylindrical portion having the same axial diameter may be provided between the reduced diameter portion 31 and the first enlarged diameter portion 32 .

[0019] <Second enlarged diameter part 33> The second enlarged diameter section 33 is a portion closer to the other end opening side than the reduced diameter section 31, and the inner diameter becomes larger toward the open end of the other end opening. The second enlarged diameter section 33 in this embodiment is in a truncated cone shape, communicating with the reduced diameter section 31, and having an inner diameter surface tapered at a predetermined inclination angle over the entire circumference in the circumferential direction. A straight cylindrical section having the same axial diameter may be provided between the reduced diameter section 31 and the second enlarged diameter section 33.

[0020] Furthermore, the second expanded diameter portion 33 may be configured as a cylindrical portion having a uniform inner diameter along the axial direction, but is preferably tapered in order to reduce pressure loss. In addition, in the burner efficiency improving attachment part 3 of this embodiment, the opening of the other end opening is set to have the same shape and dimensions as the opening of the air intake port 21a of the radiant tube 21. That is, if the opening shape of the air intake port 21a is circular, the opening of the other end opening is also the same circular shape. Also, if the opening shape of the air intake port 21a is elliptical, the opening of the other end opening is also the same elliptical shape.

[0021] This makes it possible to connect the other end opening to the air intake port 21a of the radiant tube 21 in a sealed state. Here, in the burner efficiency improving attachment part 3 of this embodiment, the inner diameter of the reduced diameter portion 31 is smaller than the inner diameter of the air intake port 21a of the radiant tube 21, as shown in FIG. In addition, in the burner efficiency improving mounting part 3 of this embodiment, as shown in Figure 2, when the distance from the center of the intake and exhaust surface 11 to the center of the intake and exhaust port 12 is the pitch circle radius (D1 / 2) of the intake and exhaust port 12, the radius (D2 / 2) of the opening end on the expanded diameter portion side is larger than the pitch circle radius (D1 / 2) of the intake and exhaust port 12.

[0022] Here, if D2 is too small, there is a risk that the combustion air will leak out of the attachment part 3. If D2 is too large, on the other hand, vortices will be more likely to be generated, increasing the amount of short-pass. Moreover, if D3 is too small, the required flow rate of combustion air will not enter the passage between the fuel discharge part 13 and the attachment part 3. On the other hand, if D3 is too large, a backflow of the combustion air will occur, increasing the amount of short-passing of the combustion air. In view of the above, it is preferable to design the suitable ranges of D2 and D3 in consideration of the balance with D1 and D4, respectively. For example, the ranges of 1.2≦D2 / D1≦1.6 and 0.6≦D3 / D4≦0.9, respectively, are preferable.

[0023] In addition, in the burner efficiency improving attachment part 3 of this embodiment, the opening end on the one opening side, i.e., the surface S that defines the annular surface that constitutes the opening end face of the first enlarged diameter section 32, is a surface that is inclined in the direction of the axis P with respect to a plane perpendicular to the axis, as shown in Fig. 2. In other words, the opening end face of the first enlarged diameter section 32 is formed so as to be located on the surface S that is inclined in the direction of the axis P with respect to the plane perpendicular to the axis. As a result, the open end of first enlarged diameter portion 32 has an asymmetric shape in which one portion along the circumferential direction is shorter in axial direction from reduced diameter portion 31 than the other portion along the circumferential direction.

[0024] The opening end of the first enlarged diameter portion 32 is not limited to this as long as the part along the circumferential direction has a shorter axial distance from the reduced diameter portion 31 than the other part along the circumferential direction. This may be achieved by cutting out a part of the circumferential direction of the opening at one end. However, even if a portion of the opening end of the first enlarged diameter section 32 in the circumferential direction is relatively short in the axial direction from the reduced diameter section 31, the radius of the opening end on the first enlarged diameter section 32 side is set to be larger than the pitch circle radius of the supply and exhaust port 12 over the entire circumferential direction of the opening end. For example, the radius is set to be equal over the entire circumferential direction of the opening end of the first enlarged diameter section 32. In this case, the taper angle of the position of the first enlarged diameter section 32 in the portion that is relatively short in the axial direction from the reduced diameter section 31 is set to be relatively large.

[0025] Here, the gap between the opening end of the first enlarged diameter portion 32 and the intake / exhaust surface 11 is preferably, for example, 50 mm or more and 200 mm or less. If the gap is less than 50 mm, there is a risk that exhaust gas cannot be sufficiently sucked in. On the other hand, if the gap is more than 200 mm, the combustion air may expand and leak out of the mounting part 3 more than necessary. Further, the taper angle of the second expanded diameter portion 33 is smaller than the taper angle of the first expanded diameter portion 32 . The taper angle of the second expanded diameter portion 33 is preferably equal to or less than 20 degrees. If the taper angle of the second expanded diameter portion 33 is too large, the flow of the combustion air may separate, causing an increase in pressure loss beyond the allowable limit.

[0026] Hereinafter, the burner efficiency improving attachment part 3 will also be referred to simply as attachment part 3. (Radiant tube furnace 20) As shown in FIG. 1, a radiant tube furnace 20 of this embodiment includes a radiant tube 21 and a burner mounting device 4. The burner mounting device 4 is a frame portion that supports the single-type regenerative combustion burner 1 with the tip end side of the fuel discharge part 13 of the single-type regenerative combustion burner 1 inserted into the intake port 21a side of the radiant tube 21. The burner mounting device 4 also has an exhaust gas introduction passage 41 formed therein that is connected to the exhaust port of the radiant tube 21 and extends toward the outer circumferential space on the intake and exhaust surface 11 side of the fuel discharge part 13. The exhaust gas introduction passage 41 is a passage that guides the exhaust gas exhausted from the radiant tube 21 toward the gap between the open end of the first enlarged diameter section 32 and the supply and exhaust surface 11 from a direction along the radial direction of the enlarged diameter section. The exhaust gas introduction passage 41 shown in FIG. 1 is configured to guide the flow of exhaust gas from below toward above, and to introduce the exhaust gas from below.

[0027] (Installation of burner efficiency improvement part 3) 1, the cylindrical attachment part 3 of this embodiment is arranged coaxially on the outer periphery of the fuel discharge part 13. The attachment part 3 is arranged so that one end opening on the first enlarged diameter part 32 side and the intake and exhaust surface 11 of the burner 1 have a predetermined gap in the axial direction, and the other end opening (second enlarged diameter part 33 side) is connected to the air intake port 21a of the radiant tube 21. The connection is made by connecting a flange part provided on the air intake port 21a and a flange part provided on the other end opening by bolting or the like in such a way that gas does not leak.

[0028] 2, the circumferential orientation of the mounting part 3 is adjusted and the mounting part 3 is positioned so that the side of the opening end of the first enlarged diameter section 32 that is closer in the axial direction to the reduced diameter section 31 is downward, that is, the side facing the flow of exhaust gas sent through the exhaust gas introduction passage 41. When the surface S is tilted, the gap along the circumferential direction between the opening end of the first enlarged diameter section 32 and the intake and exhaust surface 11 is set so that the gap becomes relatively larger the closer it is to the exhaust gas introduction passage 41 side. Here, this gap serves as an exhaust gas inlet 50 to the exhaust port 12 on the exhaust side.

[0029] (Operation etc.) The mounting part 3 is a cylindrical part having a reduced diameter section 31 and a first enlarged diameter section 32 that communicates with the reduced diameter section 31. The first enlarged diameter section 32 communicates with the reduced diameter section 31 and expands in diameter toward one axial end (the intake and exhaust surface 11 side) of the mounting part 3, and has a truncated cone-shaped inner surface that forms an acute angle with respect to the axis of the mounting part 3. The first enlarged diameter section 32 faces the intake and exhaust surface 11 and the mounting part 3 with a gap in the axial direction, and the inner diameter surface of the mounting part 3 is spaced from the outer diameter surface of the cylindrical fuel discharge part 13 in the radial direction of the mounting part 3, and the mounting part 3 is disposed outside the fuel discharge part 13. As a result, a combustion air discharge passage is formed between the outer diameter surface of the fuel discharge part 13 and the inner diameter surface of the mounting part 3.

[0030] Combustion air supplied from the intake and exhaust port 12 which is a part of the intake and exhaust surface 11 is taken in from the first enlarged diameter portion 32 and guided to the reduced diameter portion 31. Furthermore, as shown in Figure 1, when the single-type regenerative combustion burner 1 with the mounting part 3 attached is used as a radiant tube burner, the burner 1 is attached with the tip side of the fuel discharge part 13 of the single-type regenerative combustion burner 1 inserted into the air intake port 21a side (inlet side) of the radiant tube 21, and the exhaust side of the radiant tube 21 is connected to the exhaust gas introduction passage 41.

[0031] The combustion air is then introduced into the radiant tube 21 through a combustion air discharge passage formed by the mounting part 3. At this time, the flow of combustion air, which is the intake air flow from the intake and exhaust ports 12 formed in the intake and exhaust surface 11, is narrowed by the first enlarged diameter section 32, so that the combustion air spreads circumferentially in the combustion air discharge passage. Furthermore, by setting D2 / 2 to be equal to or greater than D1 / 2, the combustion air from the intake / exhaust port 12 on the intake side is more reliably taken into the first enlarged diameter section 32. This makes it possible to suppress the generation of vortexes near the open end of the first enlarged diameter section 32.

[0032] Next, in this embodiment, the flow rate of the combustion air in the combustion air discharge passage is increased by narrowing the diameter at the narrowing section 31 at a position downstream of the first enlarged diameter section 32, and the flow is brought closer to the center to suppress backflow of the combustion air. According to this aspect of the present invention, the flow rate of the combustion air is increased by narrowing the diameter at the narrowing section 31, thereby preventing short pass due to backflow from the radiant tube 21.

[0033] In addition, by increasing the diameter of the second enlarged diameter portion 33 toward the air supply port 21a side, the pressure loss is reduced, the diffusion of the combustion air is promoted, and the uniformity of the combustion air in the circumferential direction is improved. Moreover, exhaust gas from radiant tube 21 is supplied toward the outer peripheral space of fuel discharge section 13 through exhaust gas introduction passage 41. Specifically, exhaust gas introduction passage 41 introduces exhaust gas discharged from the outside air side of radiant tube 21 into exhaust gas introduction port 50 formed by the gap between first expanded diameter section 32 and intake / exhaust surface 11. The exhaust gas introduced into the exhaust gas inlet 50 enters through the exhaust gas inlet 50 and is exhausted from the exhaust side intake and exhaust port 12 provided on the intake and exhaust surface 11 .

[0034] In this embodiment, since the first enlarged diameter portion 32 of the mounting part 3 and the intake and exhaust surface 11 are separated, a gap is formed between the first enlarged diameter portion 32 and the intake and exhaust surface 11 over the entire circumference in the circumferential direction, and the gap can be easily adjusted. Therefore, the interval between the first enlarged diameter portion 32 and the intake and exhaust surface 11 can be set wide. In this way, the exhaust gas inlet 50 consisting of the gap between the first enlarged diameter portion 32 and the intake and exhaust surface 11 can be formed wide and over the entire circumference in the circumferential direction, so that the intake and exhaust port 12 of the burner 1 formed on the intake and exhaust surface 11 can easily suck in the exhaust gas. That is, the exhaust of the exhaust gas is promoted. As a result, the combustion air discharged from the intake and exhaust port 12 on the intake side is relatively less likely to be sucked into the intake and exhaust port 12 on the exhaust side, and the amount of short pass to the exhaust side is reduced.

[0035] According to the study by the inventors, the exhaust gas is more easily sucked in from the intake and exhaust port 12 on the exhaust side when it is in a stagnant state (slow flow speed) than when it is flowing at a certain speed. For this reason, when the gap between the first enlarged diameter portion 32 and the intake and exhaust surface 11 is set equal over the entire circumference in the circumferential direction, the exhaust gas flow speed is relatively high and the exhaust gas is less likely to stagnate at the intake and exhaust port 12 (lower side in FIG. 1) closer to the exhaust gas introduction passage 41, so the amount of exhaust gas is smaller than that at the intake and exhaust port 12 (upper side in FIG. 1) farther from the exhaust gas introduction passage 41. In other words, the intake and exhaust port 12 far from the exhaust gas introduction passage 41 and where the exhaust gas flow speed is low has a larger exhaust amount than the intake and exhaust port 12 close to the exhaust gas introduction passage 41, and as a result, the intake and exhaust port 12 on the lower side has a relatively larger short-pass amount of combustion air during exhaust.

[0036] In contrast, in this embodiment, as shown in Fig. 2, the surface S that defines the opening end of the first enlarged diameter portion 32 is inclined in the axial direction with respect to the plane perpendicular to the axis of the mounting part 3. As a result, the distance between the opening end of the first enlarged diameter portion 32 and the supply and exhaust surface 11 of the burner 1 is relatively increased as it approaches the exhaust gas introduction passage 41. Therefore, as shown in Fig. 2, exhaust is promoted by widening the exhaust gas introduction port 50 on the lower supply and exhaust port 12 side close to the exhaust gas introduction passage 41, and the difference in the amount of short passes due to the position of each supply and exhaust port 12 in the circumferential direction is reduced. That is, in this embodiment, it is possible to reduce the overall amount of short passes.

[0037] This makes it possible to reduce the difference in the amount of short passes depending on the position of each air supply and exhaust port 12 arranged circumferentially on the air supply and exhaust surface 11, thereby reducing the overall amount of short passes. 3 and 4 are schematic diagrams illustrating the flow 70 of combustion air and the flows 60 and 61 of exhaust gas. Fig. 3 is a diagram showing the case where the lower intake and exhaust port 12B closer to the exhaust gas introduction passage 41 is on the exhaust side. Fig. 4 is a diagram showing the case where the upper intake and exhaust port 12A farther from the exhaust gas introduction passage 41 is on the exhaust side.

[0038] 3, since the flow velocity of exhaust gas 60 from exhaust gas introduction passage 41 is high, it tends to be difficult to draw in exhaust gas from exhaust gas introduction port 50. In contrast, in this embodiment, by relatively widening exhaust gas introduction port 50 in the lower portion, the introduction of exhaust gas into lower intake and exhaust port 12 is promoted and the intake of combustion air from upper intake and exhaust port 12 is suppressed. The flow of exhaust gas indicated by reference numeral 61 indicates the flow of exhaust gas that is drawn into the flow of combustion air from the upper intake and exhaust port 12 by the ejector effect and is recirculated.

[0039] In the case of Fig. 4, the exhaust gas that is delivered stagnates in the space above the mounting portion, slowing down the flow rate of the exhaust gas. The slowed-down exhaust gas is sucked in from the upper intake and exhaust port 12A as shown by exhaust gas flow 60. In this case, the exhaust gas inlet 50 in the upper portion is relatively small, but the exhaust rate from the exhaust gas intake and exhaust port 12A is about the same as the exhaust rate from the lower intake and exhaust port 12B.

[0040] (others) The present disclosure may also have the following configuration. (1) For a single-type regenerative combustion burner having an intake and exhaust surface with multiple intake and exhaust ports and a cylindrical fuel discharge portion protruding forward from the center of the intake and exhaust surface, an attachment part is disposed on the outer periphery of the fuel discharge portion to improve burner efficiency, the attachment part is a cylindrical part whose minimum inner diameter is larger than the outer diameter of the cylindrical fuel discharge part, and which is used with its axis oriented in the same direction as the axis of the fuel discharge part, its inner diameter surface facing the outer diameter surface of the fuel discharge part with a gap therebetween and its one end opening facing the intake and exhaust surface with a gap therebetween; The cylindrical attachment parts are: A reduced diameter section in the middle of the axial direction, in which the inner diameter is reduced, a diameter expanding portion that is a portion closer to the one end opening side than the diameter reducing portion and has an inner diameter that becomes larger toward the one end opening side; Equipped with.

[0041] (2) A second expanding diameter portion is provided in the other end opening portion on the opposite side of the one end opening from the reduced diameter portion, and the inner diameter of the second expanding diameter portion increases toward the opening end of the other end opening. (3) The single-type regenerative combustion burner is installed in a state in which the tip opening side of the cylindrical fuel discharge portion is inserted into the air intake port of a radiant tube of a radiant tube furnace, and the attachment part is disposed on the single-type regenerative combustion burner, The opening at the other end opposite to the one end opening has the same shape and dimensions as the opening of the air supply port.

[0042] (4) When the distance from the center of the intake and exhaust surface to the center of the intake and exhaust port is the pitch circle radius of the intake and exhaust port, The inside diameter of the open end on the expanded diameter portion side is larger than the pitch circle radius of the air supply and exhaust port. (5) The opening end on the one-end opening side has a circumferential portion that is shorter in axial direction from the reduced diameter portion than other circumferential portions. (6) The surface that defines the annular surface along the circumferential direction of the opening end surface on the one opening side is a surface that is inclined in the axial direction with respect to a plane perpendicular to the axis.

[0043] (7) A mounting structure for a burner efficiency improving mounting part according to the present disclosure, comprising: The attachment part is attached to the outer periphery of the fuel discharge part with its axis oriented in the same direction as the axis of the fuel discharge part and with one end opening facing the intake and exhaust surface with a gap therebetween. An example of an attachment part for improving burner efficiency according to the present disclosure is a cylindrical part whose minimum inner diameter is larger than the outer diameter of the cylindrical fuel discharge part, and which is used with its axis oriented in the same direction as the axis of the fuel discharge part, with its inner diameter surface facing the outer diameter surface of the fuel discharge part with a gap and with its one end opening facing the air intake and exhaust surface with a gap, wherein the cylindrical attachment part comprises a reduced diameter section in the middle of the axial direction where the inner diameter is narrowed to a small diameter, and an expanded diameter section which is on the one end opening side closer to the reduced diameter section and has an inner diameter that becomes larger toward the opening end of the one end opening, and a second expanded diameter section which is on the other end opening opposite the reduced diameter section to the one end opening and has an inner diameter that becomes larger toward the opening end of the other end opening.

[0044] (8) The single-type regenerative combustion burner is attached to equipment in which the tip opening side of the cylindrical fuel discharge portion is inserted into the air intake port of the radiant tube of a radiant tube furnace, The opening of the other end opposite to the one end opening has the same shape and dimensions as the opening of the air supply port, and the other end opening is connected to the air supply port.

[0045] (9) The exhaust gas supply pipe is attached to a facility having an exhaust gas introduction passage that guides the exhaust gas exhausted from the radiant tube toward the gap between the one end opening and the intake and exhaust surface from a direction along the radial direction of the expanded portion, The opening end on the one-end opening side has a structure in which a portion along a circumferential direction is shorter in axial distance from the reduced diameter portion than other portions along the circumferential direction, The mounting parts are positioned so that the size of the circumferential gap between the one end opening and the air supply and exhaust surface is larger on the side where the exhaust gas introduction passage is located than in other parts. EXAMPLES

[0046] Next, examples based on this embodiment will be described. As described above, in Fig. 2, D1 is the pitch circle diameter of the intake and exhaust port 12, D2 is the inner diameter of the opening end of the first enlarged diameter section 32 of the mounting part 3, D3 is the inner diameter of the reduced diameter section 31 of the mounting part 3, and D4 is the inner diameter of the intake port 21a side of the radiant tube 21. Also, A represents the maximum value of the difference in distance between the opening end of the first enlarged diameter section 32 and the intake and exhaust surface 11 of the burner 1 depending on the circumferential position. The position of the maximum value is set to be on the lower side as shown in Fig. 2. "Experimental Example 1" In the experimental example 1, D3=D4=170 mm, the attachment part 3 was not formed with the reduced diameter portion 31, and only the first enlarged diameter portion 32 was formed. The short pass rate was then determined when the inside diameter D2 of the opening end of the first expanded diameter portion 32 was changed. The results are shown in Table 1. Here, the short-pass rate is the ratio of the amount of combustion air exhausted after a short pass to the amount of combustion air supplied.

[0047] [Table 1]

[0048] As can be seen from Table 1, as D2 / D1 becomes smaller, the short pass rate becomes higher. That is, when D2 / D1 becomes small, the combustion air is more likely to leak out of the first enlarged diameter portion 32 of the attachment part 3. The leaked combustion air is then exhausted from the exhaust intake / exhaust port 12 together with the exhaust gas, resulting in an increased short-pass rate. It is preferable that D2 / D1 is 1.2 or more. "Experimental Example 2" Next, the short pass rate was obtained when the inner diameter D3 of the reduced diameter portion 31 was changed while D2 / D1 was fixed at 1.4. The results are shown in Table 2.

[0049] [Table 2]

[0050] As can be seen from Table 2, when D3 / D4 is 1 or more, the short pass rate increases significantly. From the results in Table 2, it was found that by narrowing the inner diameter of reduced diameter portion 31 to be equal to or smaller than the inner diameter of radiant tube 21, the short pass rate was reduced compared to the case where reduced diameter portion 31 was provided. Here, if D3 / D4 is less than 1, the attachment part 3 has a tapered second expanded diameter portion 33. "Experimental Example 3" Furthermore, the short pass rate was calculated when the offset amount A in Figure 2 was changed. The results are shown in Table 3. In this experimental example, the settings are D1=170 mm, D2=240 mm, and D3=100 mm.

[0051] [Table 3]

[0052] As can be seen from Table 3, it was found that the short-pass rate of combustion air can be reduced by relatively increasing the distance in the circumferential direction between the opening end of the large diameter portion closer to the exhaust gas introduction passage 41 and the intake and exhaust surface 11. [Explanation of symbols]

[0053] 1. Single-type regenerative combustion burner 3 Installation parts 10 Heat storage body 11 Air intake and exhaust 12 Air supply and exhaust vent 13 Fuel discharge part 13a Fuel outlet 14 Intake and exhaust switching valve 20 Radiant tube furnace 21 Radiant tube 21a Air supply port 31 Reduced diameter part 32 1st expanded diameter section (expanded diameter section) 33 Second enlarged diameter section 40 Burner mounting device 41 Exhaust gas inlet passage 50 Exhaust gas inlet S Prescribed surface

Claims

1. A mounting part for a single-type regenerative heat combustion burner having an intake and exhaust surface with a plurality of intake and exhaust ports and a cylindrical fuel discharge part protruding forward from the center of the intake and exhaust surface, the mounting part being disposed on the outer periphery of the fuel discharge part to improve burner efficiency, the attachment part is a cylindrical part whose minimum inner diameter is larger than the outer diameter of the cylindrical fuel discharge part, and which is used with its axis oriented in the same direction as the axis of the fuel discharge part, its inner diameter surface facing the outer diameter surface of the fuel discharge part with a gap therebetween and its one end opening facing the intake and exhaust surface with a gap therebetween; The cylindrical attachment parts are: A reduced diameter section in the middle of the axial direction, in which the inner diameter is reduced, a diameter expanding portion that is a portion closer to the one end opening side than the diameter reducing portion and has an inner diameter that becomes larger toward the one end opening side; Equipped with a second enlarged diameter portion which is a portion of the other end opening on the opposite side of the one end opening from the reduced diameter portion and has an inner diameter which becomes larger toward the opening end of the other end opening, A mounting part for improving burner efficiency.

2. The single-type regenerative combustion burner is installed in a state in which the tip opening side of the cylindrical fuel discharge portion is inserted into the air intake port of the radiant tube of a radiant tube furnace, and the attachment part is disposed on the single-type regenerative combustion burner, The opening at the other end opposite to the one end opening has the same shape and dimensions as the opening of the air supply port.

2. A burner efficiency improving attachment according to claim 1.

3. The single-type regenerative combustion burner is installed in a state in which the tip opening side of the cylindrical fuel discharge portion is inserted into the air intake port of the radiant tube of a radiant tube furnace, and the attachment part is disposed on the single-type regenerative combustion burner, The opening at the other end opposite to the one end opening has the same shape and dimensions as the opening of the air supply port.

2. A burner efficiency improving attachment according to claim 1.

4. When the distance from the center of the intake and exhaust surface to the center of the intake and exhaust port is defined as the pitch circle radius of the intake and exhaust port, The radius of the opening end on the enlarged diameter portion side is larger than the pitch circle radius of the air supply and exhaust port.

2. A burner efficiency improving attachment according to claim 1.

5. When the distance from the center of the intake and exhaust surface to the center of the intake and exhaust port is defined as the pitch circle radius of the intake and exhaust port, The radius of the opening end on the enlarged diameter portion side is larger than the pitch circle radius of the air supply and exhaust port.

3. A burner efficiency improving attachment according to claim 2.

6. When the distance from the center of the intake and exhaust surface to the center of the intake and exhaust port is defined as the pitch circle radius of the intake and exhaust port, The radius of the opening end on the enlarged diameter portion side is larger than the pitch circle radius of the air supply and exhaust port.

4. A burner efficiency improving attachment according to claim 3.

7. a circumferential portion of the opening end on the one-end opening side is located at an axial distance from the reduced diameter portion shorter than another circumferential portion of the opening end; 7. A mounting part for improving burner efficiency according to any one of claims 1 to 6.

8. The surface defining the annular surface along the circumferential direction of the opening end surface on the one end opening side is a surface inclined in the axial direction with respect to a plane perpendicular to the axis, 8. A burner efficiency improving attachment according to claim 7.

9. A mounting structure for a mounting part for improving burner efficiency, which is disposed on the outer periphery of a fuel discharge part for a single-type regenerative heat combustion burner having an intake and exhaust surface with a plurality of intake and exhaust ports opening therein and a cylindrical fuel discharge part protruding forward from a center part of the intake and exhaust surface, comprising: the attachment part is a cylindrical part whose minimum inner diameter is larger than the outer diameter of the cylindrical fuel discharge part, and which is used with its axis oriented in the same direction as the axis of the fuel discharge part, its inner diameter surface facing the outer diameter surface of the fuel discharge part with a gap therebetween and its one end opening facing the intake and exhaust surface with a gap therebetween; The cylindrical attachment part includes a reduced diameter section having an inner diameter narrowed to a small diameter in an axially intermediate portion, and an expanded diameter section that is located on the one-end opening side from the reduced diameter section and has an inner diameter that becomes larger toward the opening end of the one-end opening, a second enlarged diameter portion which is a portion of the other end opening on the opposite side of the one end opening from the reduced diameter portion and has an inner diameter which becomes larger toward the opening end of the other end opening, The attachment part is attached to the outer periphery of the fuel discharge part with its axis oriented in the same direction as the axis of the fuel discharge part and with one end opening facing the intake and exhaust surface with a gap therebetween. A mounting structure characterized by:

10. The single-type regenerative combustion burner is attached to equipment in which the tip opening side of the cylindrical fuel discharge portion is inserted into the air intake port of the radiant tube of a radiant tube furnace, The opening of the other end opening opposite to the one end opening is configured to have the same shape and dimensions as the opening of the air supply port, and the other end opening is connected to the air supply port.

10. The mounting structure according to claim 9.

11. The exhaust gas introduction passage is attached to equipment that guides the exhaust gas exhausted from the radiant tube toward the gap between the one end opening and the intake and exhaust surface from a direction along the radial direction of the expanded diameter portion, The opening end on the one-end opening side has a structure in which a portion along a circumferential direction is shorter in axial distance from the reduced diameter portion than other portions along the circumferential direction, a mounting part is arranged so that the size of the gap between the one end opening and the intake and exhaust surface along the circumferential direction is larger on the side where the exhaust gas introduction passage is arranged than on the other part; 11. The mounting structure according to claim 9 or 10.

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