Gas burner and boiler comprising the same

Abstract

To provide a gas burner that can keep sealability in a through hole through which a burner body penetrates a wind box, and allow deformation caused by a thermal elongation difference.SOLUTION: A gas burner 1 comprises a wind box 3, and a burner body 5 for supplying gas fuel to a furnace 7 of a boiler. The burner body 5 comprises: a tip part 10 extending in the direction of a first horizontal axis L1 toward the furnace 7, and fixed to the wind box 3; and a base end part 12 penetrating a through hole 22 provided in a rear wall part 3a of the wind box 3. The rear wall part 3a comprises: a detachable wall part 3a1 located in the direction of the first horizontal axis L1, and capable of being detached; and a fixed wall part 3a2 provided at a position separated from the first horizontal axis L1 with respect to the detachable wall part 3a1, and in which the through hole 22 is formed. The through hole 22 is provided with an elastic deformation part 30 for airtightly sealing the through hole 22, and allowing a relative movement of the base end part 12 with respect to the rear wall part 3a.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a gas burner and a boiler equipped with the same. [Background technology]

[0002] A gas burner that supplies gas fuel to a boiler to form a flame is known (Patent Document 1). Patent Document 1 discloses an invention related to reducing gas leakage caused by differential thermal expansion in a flange portion that connects a burner panel to a wind box that houses multiple burner nozzles. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-110829 Summary of the Invention [Problem to be solved by the invention]

[0004] As shown in Patent Document 1, gas burners require leakage countermeasures for the wind box to prevent gas leakage. Patent Document 1 considers leakage countermeasures between the furnace wall (burner panel) and the wind box, but it is also necessary to consider the sealing performance of the through hole through which the burner body penetrates from the wind box to the outside of the furnace. It is also necessary to consider deformation due to the thermal expansion difference between the burner body and the wind box at the through hole.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a gas burner and a boiler equipped with the same that can maintain sealing in the through hole through which the burner body passes through the wind box while allowing deformation due to differential thermal expansion. [Means for solving the problem]

[0006] A gas burner according to one embodiment of the present disclosure comprises a wind box to which combustion air is supplied, and a burner body provided inside the wind box and supplying gas fuel to a furnace of a boiler, the burner body comprising a tip portion extending in an axial direction toward the furnace and fixed to the wind box, and a base portion connected to the tip portion and extending toward the base end to pass through a through hole provided in a rear wall portion of the wind box, the rear wall portion comprising a first wall portion located in the axial direction and removable, and a second wall portion provided at a position spaced from the axis with respect to the first wall portion and having the through hole formed therein, the through hole being provided with an elastic deformation portion that hermetically seals the through hole and allows relative movement of the base end with respect to the rear wall portion.

[0007] A boiler according to one aspect of the present disclosure includes a boiler body and the above-mentioned gas burner provided to the boiler body. Effect of the Invention

[0008] It is possible to maintain the sealing performance at the through hole through which the burner body passes through the wind box, and to allow deformation due to differential thermal expansion. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing a gas burner according to an embodiment of the present disclosure, taken along a horizontal plane; [Diagram 2] 2 is a cross-sectional view showing the gas burner of FIG. 1 cut along a vertical plane. [Diagram 3] 2 is an enlarged cross-sectional view showing the periphery of an elastic deformation portion of FIG. 1. [Figure 4] FIG. 4 is a cross-sectional view showing a state in which an adjustment bolt is removed from the gas burner of FIG. [Diagram 5] FIG. 2 is a schematic cross-sectional view illustrating the gas burner when installed. [Figure 6] FIG. 2 is a schematic cross-sectional view showing the expansion and contraction state of an expansion part of a gas burner. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0011] A gas burner 1 provided in a boiler is shown in Fig. 1. Fig. 1 shows a cross section of the gas burner 1 cut along a horizontal plane and viewed in plan.

[0012] The gas burner 1 comprises an air box 3 into which the combustion air is introduced, and a burner body 5 through which gas fuel flows. In the figure, the left side of the gas burner 1 is the boiler furnace 7. The furnace 7 side is the tip side of the gas burner 1, and the opposite side (the right side in the figure) is the base end side of the gas burner 1.

[0013] The wind box 3 is attached to the wall of the boiler and houses the burner body 5 inside. Combustion air to be supplied to the furnace of the boiler is supplied inside the wind box 3. The combustion air is heated by heat exchange with the combustion gas generated in the boiler, and is set to a temperature of about 300°C.

[0014] The burner body 5 includes a tip portion 10 located on the tip side and a base end portion 12 connected to the tip portion and extending to the base end side (the right side in the drawing).

[0015] A nozzle 14 is provided at the tip 10. The nozzle 14 rotates around a rotation axis L0. Specifically, as shown in Fig. 2, the nozzle 14 rotates in the vertical direction as indicated by an arrow A1 with the rotation axis L0 as the center (fulcrum). Fig. 2 is a cross-sectional view of the gas burner 1 cut along a vertical plane. As shown in Fig. 1, the nozzle 14 is driven by a rotation mechanism 16 equipped with a link.

[0016] The tip portion 10 has a flat portion 18 provided on the base end side of the nozzle 14. The flat portion 18 is shaped so that it becomes wider from the base end side to the tip end side as shown in Fig. 1, and the dimension (thickness) in the height direction gradually decreases from the base end side to the tip end side as shown in Fig. 2. The tip side of the flat portion 18 is connected to the ejection portion 20, and the gas fuel guided from the flat portion 18 is ejected from the ejection portion 20 toward the furnace 7.

[0017] 1, the left and right sides of the flat portion 18 are fixed to the wind box 3 via fixing pieces 18a. As a result, the tip portion 10 of the burner body 5 is fixed to the wind box 3.

[0018] As shown in Fig. 1, the tip portion 10 extends in the direction of a first horizontal axis (axis) L1. Therefore, a tip side 12a of the base end portion 12 of the burner body 5 is fixed to the base end side of the flat portion 18 and extends in the direction of the first horizontal axis L1. On the other hand, a base end side 12b of the base end portion 12 extends in the direction of a second horizontal axis L2 spaced apart from the first horizontal axis L1. The base end side 12b of the base end portion 12 is inserted into a through hole 22 formed in the rear wall portion 3a of the wind box 3.

[0019] The base end 12 is, for example, a tubular body having a circular cross section, and has a first bent portion 12c and a second bent portion 12d that are bent at a predetermined curvature in a horizontal plane by approximately 90°. The first bent portion 12c and the second bent portion 12d form the base end 12 into a crank shape. The curvatures of the bent portions 12c and 12d are determined in consideration of the thermal elongation of the gas burner 1 so that no stress concentration occurs during deformation and the bending stress is equal to or less than a predetermined value.

[0020] The through hole 22 is formed in a fixed wall portion (second wall portion) 3a2 constituting the rear wall portion 3a of the wind box 3. The fixed wall portion 3a2 is fixed to an adjacent wall portion by welding or the like without being removed from the wind box 3. A removable wall portion 3a1 (first wall portion) is provided next to the fixed wall portion 3a2.

[0021] The removable wall 3a1 constitutes the rear wall 3a of the wind box 3, and is located on the base end side (rear side) of the tip 10 of the burner body 5, on an extension of the first horizontal axis L1. The removable wall 3a1 is fixed to the wind box 3 by fixing bolts and nuts 24 attached to the outer periphery, and can be removed from the wind box 3 by removing the fixing bolts and nuts 24. By removing the removable wall 3a1, the worker can visually check and work on parts accommodated in the wind box 3, such as the tip 10 of the burner body 5, in the direction of the first horizontal axis L1.

[0022] A heat insulating material 26 is provided on the rear wall 3a of the wind box 3, that is, on the inside of the removable wall 3a1 and the fixed wall 3a2 (on the inner side of the wind box 3).

[0023] The through hole 22 is provided with an elastic deformation portion 30 that airtightly seals the inside and outside of the wind box 3 and allows relative movement between the base end portion 12 of the burner body 5 and the fixed wall portion 3a2 of the wind box 3.

[0024] As shown enlarged in Figure 3, the elastic deformation portion 30 includes a wind box side fixed portion 32 fixed to the inner wall 3b of the fixed wall portion 3a2 of the wind box 3, a base end side fixed portion 34 fixed to the base end side 12b of the base end 12 of the burner body 5, and an expansion portion 36 extending between these fixed portions 32, 34.

[0025] The wind box side fixed part 32 includes a flange part 32a fixed to the inner wall 3b by welding or the like, and a cylindrical part 32b fixed to the flange part 32a so as to extend towards the base end side (the right side in FIG. 3) thereof.

[0026] The base end side fixing part 34 includes a flange part 34a fixed to the base end 12 of the burner body 5 and a cylindrical part 34b fixed to extend toward the tip side (left side in FIG. 3) of the flange part 34a. The flange part 34a is fixed to the base end 12 by welding via an annular part 34c. A stopper ring 34d protruding in the radial direction is fixed to the tip side of the cylindrical part 34b.

[0027] An adjustment disk 34e protruding in the radial direction is fixed to the base end side of the cylindrical portion 34b. An adjustment bolt 38 can be inserted into the adjustment disk 34e. The tip of the adjustment bolt 38 is screwed into the fixing nut 22c. The fixing nut 22c is fixed to the adjustment disk 22b protruding in the inner diameter direction from the base end side (the right side in FIG. 3) of the through hole wall portion 22a that defines the through hole 22.

[0028] A pair of adjustment nuts 40 are screwed onto the adjustment bolt 38. By clamping and fixing the adjustment disk 34e between the pair of adjustment nuts 40, the position of the base end side fixing part 34 with respect to the adjustment bolt 38 can be temporarily fixed. As will be described later, this allows the preload (preset) of the expansion part 36 to be adjusted.

[0029] The expansion portion 36 is cylindrical and bellows-shaped, and allows expansion and contraction of the second horizontal axis L2 and deformation in the bending direction. The base end portion 12 of the burner body 5 is inserted into the inside of the expansion portion 36.

[0030] By forming a labyrinth-shaped flow path by the stopper ring 34d protruding radially and the adjustment disk 22b protruding inwardly, it is possible to suppress gas outflow even in the unlikely event that gas inside the wind box 3 leaks from the expansion section 36 or the like.

[0031] The adjustment bolt 38 and the adjustment nut 40 are removed after being installed on-site and the preload of the expansion section 36 is adjusted. Fig. 4 shows a state in which the adjustment bolt 38 and the adjustment nut 40 have been removed. Therefore, during operation of the gas burner 1, the adjustment bolt 38 and the adjustment nut 40 are removed as shown in Fig. 4. The adjustment bolt 38 is also used during transportation from the factory to the site, and can also be used as a fixing bolt during transportation so that no load is applied to the expansion section 36 during transportation.

[0032] Next, a process of applying a preload to the expansion part 36 to perform preset will be described with reference to Fig. 5. As shown in Fig. 5(a), the burner body 5 is transported to the site and the base end 12 of the burner body 5 is inserted into the through hole 22. At this time, the base end 12 and the base end side fixing part 34 are not fixed to each other.

[0033] Then, as shown in FIG. 5(b), a compressive force is applied to shorten the length of the expansion portion 36, and a preset is performed at a position where the length is a predetermined length, and the base end portion 12 and the base end side fixing portion 34 are fixed by welding. Specifically, as shown in FIG. 3, the adjustment nut 40 is rotated with respect to the adjustment bolt 38 to change the relative position. The adjustment disk 34e is fixed by the adjustment nut 40 at a position where a predetermined preload is applied. Then, the annular portion 34c is fixed to the outer periphery of the base end portion 12 by performing a fillet weld W. As a result, the expansion amount of the expansion portion 36 is given as a predetermined value in a cold state (a state in which the boiler is stopped and the temperature is approximately the ambient temperature).

[0034] Then, as shown in FIG. 5(c), after the base end portion 12 and the base end side fixing portion 34 are fixed, the adjustment bolt 38 and the adjustment nut 40 are removed to allow the expansion portion 36 to deform in response to thermal deformation.

[0035] FIG. 6 shows the expansion and contraction state of the expansion section 36. FIG. 6(a) shows the state before the preset (no pressure is applied to the expansion section 36), FIG. 6(b) shows the cold state (the boiler is stopped after the preset), FIG. 6(c) shows the boiler startup (the boiler is operating, the gas burner is not ignited), and FIG. 6(d) shows the gas burner 1 is ignited. As can be seen from the figure, in the state before the preset (FIG. 6(a)), the tip end (on the expansion section 36 side) of the cylindrical section 34b of the base end side fixing section 34 is in position (1), and the expansion section 36 is in a state where there is no stress. From the cold state (FIG. 6(b)), at the time of the boiler startup (when the gas burner is not ignited: FIG. 6(c)), it becomes position (3), and at the time of the gas burner ignition (FIG. 6(d)), the gas fuel flows through the burner body 5, so the burner body 5 is cooled more than at the time of the boiler startup and becomes position (2). Basically, the number of times the burner is turned on and off is greater than the number of times the boiler is started, so that the expansion and contraction between position (2) and position (3) is repeated the most. FIG. 6(a) shows the position (1) of the base end side fixing part 34 before the preset, that is, when the expansion part 36 is not stressed, and is adjusted to be between the position (2) of the base end side fixing part 34 when the gas burner is ignited and the position (3) of the base end side fixing part 34 when the boiler is started. In other words, the preset is performed so as to reduce the stress applied to the expansion part 36 by the repeated expansion and contraction between the position (2) of the base end side fixing part 34 when the gas burner is ignited and the position (3) of the base end side fixing part 34 when the boiler is started (the expansion part 36 in FIG. 5(b) is set to a position where it has a predetermined length), so that the average stress during the repeated expansion and contraction between the position (2) of the base end side fixing part 34 when the gas burner is ignited and the position (3) of the base end side fixing part 34 when the boiler is started can be reduced, and the fatigue life of the expansion part 36 can be improved.

[0036] Next, a comparative effect with a case where the expansion section 36 is not preset will be described. When presetting is not performed, in the cold state, no stress due to preload is generated in the expansion section 36. Compared to the cold state, the expansion section 36 expands when the boiler is started and the gas burner is ignited, generating stress. The repeated expansion and contraction between the boiler startup and the gas burner ignition occurs only on the expansion side of the expansion section 36, so the expansion and contraction are repeated under high stress. Therefore, the average stress of the expansion section 36 due to the repeated expansion and contraction between the boiler startup and the gas burner ignition when not presetting is higher than the average stress when presetting is performed.

[0037] The effects of the present embodiment described above are as follows. The removable wall 3a1 located in the direction of the first horizontal axis L1 along which the tip 10 of the burner body 5 extends is made removable. The base end 12 of the burner body 5 passes through a through hole 22 in the fixed wall 3a2 provided at a position spaced apart from the first horizontal axis L1. This allows easy access to the tip 10 of the burner body 5 by removing the removable wall 3a1 during maintenance or other work.

[0038] Since an elastically deformable portion 30 is provided between the through hole 22 and the base end portion 12 to hermetically seal them and allow relative movement, even if a thermal expansion difference occurs due to a temperature difference between the wind box 3 and the burner body 5, the elastically deformable portion 30 can hermetically seal and allow relative movement between the wind box 3 and the burner body 5. This can improve the life of the gas burner 1.

[0039] By providing the bent portions 12c and 12d at the base end 12, which are bent at a predetermined curvature, the base end 12 extending between the tip end 10 located in the direction of the first horizontal axis L1 and the through hole 22 provided on the second horizontal axis L2 away from the first horizontal axis L1 can be made into a natural shape. Even if the base end 12 is deformed due to thermal elongation, the deformation is absorbed by the bent portions 12c and 12d, so that the stress concentration generated at the base end 12 can be minimized.

[0040] Since the nozzle 14 that rotates about the rotation axis L0 is provided at the tip portion 10, it is necessary to perform maintenance on the rotation mechanism 16 of the nozzle 14. At the time of this maintenance, the removable detachable wall portion 3a1 can be used.

[0041] By using the bellows-shaped expansion portion 36, it is possible to realize the elastic deformation portion 30 that is airtight and allows relative deformation.

[0042] When the gas burner 1 is ignited, a thermal expansion difference occurs between the wind box 3 and the burner body 5 due to a temperature difference. Specifically, the wind box 3, to which preheated combustion air is supplied, thermally expands due to a rise in temperature, while the gas burner 1, to which gas fuel at room temperature is supplied, does not thermally expand as much as the wind box 3. For this reason, the rear wall of the wind box 3 moves relative to the base end 12 of the gas burner. Therefore, by applying a predetermined compressive force to the expansion section 36 in a cold state, even if a thermal expansion difference occurs after the gas burner 1 is ignited, the expansion section 36 repeats expansion and contraction on the expansion side. This makes it possible to improve the life of the expansion section 36.

[0043] The gas burner and the boiler including the gas burner according to each of the above-described embodiments can be understood, for example, as follows.

[0044] A gas burner (1) according to a first aspect of the present disclosure includes a wind box (3) to which combustion air is supplied, and a burner body (5) provided inside the wind box (3) and configured to supply gas fuel to a furnace (7) of a boiler. The burner body (5) includes a tip portion (10) extending in a direction of an axis (L1) toward the furnace (7) and fixed to the wind box (3), and a base portion (11) connected to the tip portion (10) and extending toward a base end side to pass through a through hole (22) provided in a rear wall portion (3a) of the wind box (3). The rear wall portion (3a) has a first wall portion (3a1) located in the direction of the axis (L1) and which is removable, and a second wall portion (3a2) provided at a position spaced from the axis (L1) with respect to the first wall portion (3a1) and in which the through hole (22) is formed, and the through hole (22) is provided with an elastic deformation portion (30) that hermetically seals the through hole (22) and allows relative movement of the base end portion (12) with respect to the rear wall portion (3a).

[0045] The first wall portion located in the axial direction along which the tip of the burner body extends is made removable. The base end of the burner body passes through a through hole in the second wall portion provided at a position away from the axis. This allows easy access to the tip of the burner body by removing the first wall portion during maintenance or other work. Since an elastically deformable portion is provided between the through hole and the base end portion to hermetically seal them and allow relative movement, even if a thermal expansion difference occurs between the wind box and the burner body due to a temperature difference between them, the elastically deformable portion can allow relative movement between the wind box and the burner body while still providing an airtight seal, thereby improving the lifespan of the gas burner.

[0046] In the gas burner according to a second aspect of the present disclosure, in the above-mentioned first aspect, the base end portion (12) has bent portions (12c, 12d) bent at a predetermined curvature.

[0047] By providing the base end with a bent portion bent at a predetermined curvature, the base end extending between the tip end located in the axial direction and the through hole provided at a position away from the axis can be made into a natural shape. Even if the base end is deformed due to thermal expansion, the deformation can be absorbed by the bent portion, thereby minimizing stress concentration occurring at the base end.

[0048] The gas burner according to a third aspect of the present disclosure is the first or second aspect, wherein the tip portion (10) is provided with a nozzle (14) that opens toward the furnace (7) and rotates around a fulcrum.

[0049] Since the nozzle that rotates around a fulcrum is provided at the tip, maintenance of the nozzle rotation mechanism is required. For this maintenance, the removable first wall portion can be used.

[0050] The gas burner according to a fourth aspect of the present disclosure is, in any one of the first to third aspects, characterized in that the elastic deformation portion (30) comprises a wind box side fixing portion (32) fixed to the wind box (3), a base end side fixing portion (34) fixed to the base end (12), and an expansion portion (36) having one end fixed to the wind box side fixing portion (32) and the other end fixed to the base end side fixing portion (34) and through which the base end (12) is inserted.

[0051] By using the expansion portion, it is possible to realize an elastically deformable portion that is airtight and allows relative deformation.

[0052] A gas burner according to a fifth aspect of the present disclosure is the gas burner of the above-mentioned fourth aspect, wherein the expansion portion (36) is given a predetermined compressive force in a cold state.

[0053] When the gas burner is ignited, a thermal expansion difference occurs between the wind box and the burner body due to the temperature difference. Specifically, the wind box, to which preheated combustion air is supplied, thermally expands due to a rise in temperature, while the gas burner, to which room temperature gas fuel is supplied, does not thermally expand as much as the wind box. For this reason, the rear wall of the wind box moves relative to the base end of the gas burner. Therefore, by applying a predetermined compressive force to the expansion section in a cold state, the expansion section repeats expansion and contraction on the expansion side even if a thermal expansion difference occurs after the gas burner is ignited. This can improve the life of the expansion section.

[0054] In the gas burner according to a sixth aspect of the present disclosure, in the fifth aspect described above, the specified compressive force is adjusted so that the position (1) of the base end side fixing part (34) when there is no stress on the expansion part (36) is between the position (2) of the base end side fixing part (34) when the gas burner is ignited and the position (3) of the base end side fixing part (34) when the gas burner is not ignited.

[0055] A certain compressive force is applied to the expansion section in the cold state so that the position of the expansion section when it is stress-free is adjusted to be between the position when the gas burner is ignited and the position when the boiler is started. This reduces the average stress applied to the expansion section, and improves the fatigue life of the expansion section.

[0056] A boiler according to a first aspect of the present disclosure includes a boiler body, and the gas burner (1) according to any one of the first to sixth aspects provided to the boiler body. [Explanation of symbols]

[0057] 1 Gas burner 3 Wind box 3a Rear wall 3a1 Removable wall (first wall) 3a2 Fixed wall (second wall) 3b Inner wall 5 Burner body 7 Furnace 10 Tip 12 Proximal end 12a Tip side 12b Base end 12c First bend 12d Second bending section 14 Nozzles 16 Rotation mechanism 18 Flat section 18a Fixed piece 20 Spout part 22 Through hole 22a Through hole wall 22b Adjustment disc 22c Fixing nut 24 Fixing bolts and nuts 26 Insulation 30 Elastically deformable part 32 Wind box side fixed part 32a Flange part 32b Cylindrical section 34 Base end side fixing part 34a Flange part 34b Cylindrical section 34c Circular section 34d Stopper Ring 34e Adjustment disc 36 Expansion Section 38 Adjustment bolt 40 Adjustment nut L0 Rotation axis L1 1st horizontal axis (axis) L2 2nd horizontal axis

Claims

1. a wind box to which combustion air is supplied; a burner body provided inside the wind box to supply gas fuel to a furnace of a boiler; Equipped with The burner body includes a tip portion extending in an axial direction toward the furnace and fixed to the wind box, and a base portion connected to the tip portion and extending toward the base end to pass through a through hole provided in a rear wall portion of the wind box. the rear wall portion includes a first wall portion located in the direction of the axis and removable, and a second wall portion provided at a position spaced apart from the axis with respect to the first wall portion and having the through hole formed therein; a gas burner in which the through hole is provided with an elastically deformable portion that seals the through hole airtightly and allows the base end portion to move relative to the rear wall portion.

2. 2. The gas burner according to claim 1, wherein the base end portion has a bent portion bent at a predetermined curvature.

3. 2. The gas burner according to claim 1, wherein said tip portion is provided with a nozzle which opens toward said furnace and rotates about a fulcrum.

4. 2. The gas burner according to claim 1, wherein the elastic deformation portion comprises: a wind box side fixing portion fixed to the wind box; a base end side fixing portion fixed to the base end; and an expansion portion having one end fixed to the wind box side fixing portion and the other end fixed to the base end side fixing portion, and through which the base end is inserted.

5. 5. The gas burner according to claim 4, wherein said expansion portion is given a predetermined compressive force when in a cold state.

6. 6. A gas burner as described in claim 5, wherein the specified compressive force is adjusted so that the position of the base end side fixing part when there is no stress on the expansion part is between the position of the base end side fixing part when the gas burner is ignited and the position of the base end side fixing part when the gas burner is not ignited.

7. A boiler body, The gas burner according to claim 1 provided to the boiler body; A boiler equipped with:

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