Combustion device

Abstract

To inhibit occurrence of turbulent flow in air guide members to cool a partition member efficiently.SOLUTION: In a combustion device 1 of the disclosure, two combustion chambers 34, 35 are formed sandwiching a partition member 30 in a single can body 8. A burner unit 11 is disposed in a lower part of each of the combustion chambers 34, 35. Further, fluid passing through each of heat exchangers 3, 4 may be individually heated by a combustion gas of each burner unit 11. Air guide members 49 which guide combustion air supplied from a distribution plate 38 in an upward direction along the partition member 30 are provided at heights lower than or equal to a combustion surface 67 of each burner unit 11 on both sides of the partition member 30. The distribution plate 38 is located below the pair of air guide members 49 and has a cooling air supply part including cooling air through holes 39 for supplying the combustion air to be used as cooling air to the interior of the air guide members 49. At least some of the cooling air through holes 39 are formed as burring holes 66 in each of which a peripheral edge part of the through hole 39 is erected in a cylindrical form toward the air guide member 49 side.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to combustion devices. [Background technology]

[0002] As a combustion device incorporated in a water heater, for example, the combustion device described in JP 2015-105814 A (Patent Document 1 below) is known. In this combustion device, a burner unit, a primary heat exchanger, and a secondary heat exchanger are provided in this order from the bottom. In the burner unit, a first burner group and a second burner group are arranged side by side in the left-right direction. In the primary heat exchanger, a hot water supply side primary heat exchanger located above the first burner group and a bath side primary heat exchanger located above the second burner group are arranged side by side in the left-right direction. In the secondary heat exchanger, a hot water supply side secondary heat exchanger located above the hot water supply side primary heat exchanger and a bath side secondary heat exchanger located above the bath side primary heat exchanger are arranged side by side in the left-right direction.

[0003] A single can body with internal communication is formed by assembling the middle casing of the primary heat exchanger to the top of the lower casing of the burner unit, and assembling the upper casing of the secondary heat exchanger to the top of the middle casing. The inside of the can body is divided by a partition member into a first combustion chamber in which the first burner group, the hot water supply side primary heat exchanger, and the hot water supply side secondary heat exchanger are arranged, and a second combustion chamber in which the second burner group, the bath side primary heat exchanger, and the bath side secondary heat exchanger are arranged. An air supply chamber is formed in the lower part of the lower casing, and a supply fan is connected to its lower end. A distribution plate with multiple through holes is attached to a partition plate that separates the first burner group, the second burner group, and the air supply chamber. Air sent from the air supply fan is supplied to each combustion chamber through the through holes.

[0004] The partition member is configured with a lower partition member located between the first burner group and the second burner group, a middle partition member located between the hot water supply side primary heat exchanger and the bath side primary heat exchanger, and an upper partition member located between the hot water supply side secondary heat exchanger and the bath side secondary heat exchanger. The lower partition member is configured with a middle plate located in the center in the left-right direction, a left plate located to the left of the middle plate, and a right plate located to the right of the middle plate. The lower parts of the left plate and the right plate are folded in a direction away from the middle plate at the same height as the upper end surface of the adjacent burner to form a horizontal plate part, and then folded downward so as to be parallel to the side surface of the burner to form a vertical plate part, thereby integrally forming an air guide member with a wider gap between the middle plate and the upper part than the upper part. A plurality of vents are formed in the horizontal plate part of the air guide member. The combustion air supplied to the air guide member from the distribution plate is discharged upward to each combustion chamber through the vents. The combustion air cools the left and right plates at the top of the partition member. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2015-105814 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the above-described combustion apparatus, turbulence may occur within the air guide member, which may result in failure to effectively cool the left and right plates at the top of the partition member. [Means for solving the problem]

[0007] The combustion device disclosed herein has two combustion chambers formed in a single can body with a partition member between them, a burner unit disposed below each combustion chamber, and a heat exchanger disposed above each combustion chamber, and an air supply chamber separated by a distribution plate having a plurality of through holes formed therein is formed below the two combustion chambers, and an air supply fan connected to the air supply chamber supplies combustion air from the air supply chamber through the distribution plate to each combustion chamber, so that fluid passing through each heat exchanger can be individually heated by the combustion gas of each burner unit. This combustion device comprises air guide members on both sides of the partition member, which guide the combustion air supplied from the distribution plate in an upward direction along the partition member, at a height below the combustion surface of each of the burner units, and the distribution plate is located below the pair of air guide members and has a cooling air supply section with a plurality of cooling air through holes for supplying the combustion air as cooling air into the air guide member, and at least some of the cooling air through holes are burring holes whose peripheral portions rise cylindrically toward the air guide member. Effect of the Invention

[0008] According to the present disclosure, the generation of turbulence within the air guide member is suppressed, and the partition member can be efficiently cooled. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a front view of the combustion device. [Diagram 2] FIG. 2 is a perspective view of the combustion device as seen obliquely from the front right. [Diagram 3] FIG. 3 is a perspective view of the combustion device as seen obliquely from the rear left. [Figure 4] FIG. 4 is an exploded perspective view of the combustion device. [Diagram 5] FIG. 5 is a cross-sectional view of the combustion device. [Figure 6] FIG. 6 is an enlarged cross-sectional view of a portion of FIG. [Figure 7]FIG. 7 is a perspective cross-sectional view of the lower partition member as viewed diagonally from the front left. [Figure 8] FIG. 8 is a perspective cross-sectional view of the cooling air through-hole as viewed diagonally from the front left. [Figure 9] FIG. 9 is a perspective view of the distribution plate. [Figure 10] FIG. 10 is a bottom view of the distribution plate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Description of the embodiments of the present disclosure] First, the embodiments of the present disclosure will be listed and described. [1] The combustion device disclosed herein has two combustion chambers formed in a single can body with a partition member between them, a burner unit disposed at the bottom of each combustion chamber, and a heat exchanger disposed at the top of each of the combustion chambers. An air supply chamber separated by a distribution plate having a plurality of through holes is formed below the two combustion chambers, and an air supply fan connected to the air supply chamber supplies combustion air from the air supply chamber through the distribution plate to each of the combustion chambers, so that the combustion gas from each burner unit can individually heat each of the fluids passing through each of the heat exchangers. This combustion device comprises air guide members on both sides of the partition member, which guide the combustion air supplied from the distribution plate in an upward direction along the partition member, at a height below the combustion surface of each of the burner units, and the distribution plate is located below the pair of air guide members and has a cooling air supply section with a plurality of cooling air through holes for supplying the combustion air as cooling air into the air guide member, and at least some of the cooling air through holes are burring holes whose peripheral portions rise cylindrically toward the air guide member.

[0011] At least some of the cooling air through holes are burred holes whose peripheral edges rise cylindrically toward the air guide member, so that the air supplied from the air supply fan is guided upward by the cylindrical rising portion as it enters the air guide member. This prevents turbulence from occurring within the air guide member, and enables the partition member to be cooled efficiently.

[0012] [2] In the above item [1], it is preferable that the partition member extends in the front-to-rear direction, the plurality of cooling air through holes are composed of a plurality of the burring holes and a plurality of non-burring holes without burring, and the plurality of non-burring holes include non-burring holes arranged in a manner such that they are located between a pair of the burring holes adjacent to each other in the front-to-rear direction.

[0013] If all cooling air through holes are burring holes, the peripheral portions of all the through holes must be raised, so the number of burring holes is limited, making it difficult to supply cooling air sufficiently into the air guide member. In order to solve this problem and the problem of turbulence described above, the non-burring holes are arranged in such a manner that a plurality of non-burring holes are located between a pair of burring holes adjacent to each other in the front-rear direction. This ensures the number of cooling air through holes and allows a sufficient amount of cooling air to be supplied into the air guide member, despite the presence of burring holes. In addition, the air flow from the burring holes can guide the air from the non-burring holes upward, so that the generation of turbulence in the air guide member can be prevented, and the partition member can be efficiently cooled.

[0014] [3] In the above [1] or [2], it is preferable that the burring hole has a flat shape with a diameter in the front-rear direction shorter than a diameter in the left-right direction.

[0015] In order to increase the number of burring holes arranged in the front-rear direction while taking into account the processing limits, it is desirable to reduce the diameter of the burring holes in the front-rear direction. However, simply reducing the diameter in the front-rear direction will reduce the amount of air passing through the burring holes accordingly. Therefore, by making the burring holes flatter in that the diameter in the front-rear direction is shorter than the diameter in the left-right direction, it is possible to increase the number of burring holes and ensure the amount of air.

[0016] [Details of the embodiment of the present disclosure] Specific examples of the combustion device of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0017] (Combustion Equipment 1) The combustion device 1 shown in Figures 1 to 4 is incorporated into a water heater for use. The combustion device 1 is provided with, from the bottom, a burner section 2, a primary heat exchanger 3, and a secondary heat exchanger 4, in that order. The burner section 2 has a lower casing 5. The primary heat exchanger 3 has a middle casing 6. The secondary heat exchanger 4 has an upper casing 7. By assembling the middle casing 6 to the top of the lower casing 5, and assembling the upper casing 7 to the top of the middle casing 6, a single can body 8 with internal communication is formed.

[0018] (Burner section 2) The burner section 2 includes a first burner group 9 and a second burner group 10. The first burner group 9 and the second burner group 10 are arranged side by side in the left-right direction. Each burner group 9, 10 includes a plurality of burner units 11 that are flat and have flame holes formed on their upper end surfaces (combustion surfaces 67 described later). The plurality of burner units 11 are arranged side by side in the left-right direction. A mixing tube 12 is provided at the bottom of each burner unit 11. A nozzle (not shown) connected to a gas supply pipe is provided at the front end of the mixing tube 12 so that primary air for combustion is supplied together with gas. Here, the first burner group 9 is used for hot water supply, and the second burner group 10 is used for bath reheating, and the number of burner units 11 in the first burner group 9, which has a larger capacity, is greater than the number of burner units 11 in the second burner group 10.

[0019] (Primary heat exchanger 3) The primary heat exchanger 3 comprises a hot water supply side primary heat exchanger 13 located above the first burner group 9, and a bath side primary heat exchanger 14 located above the second burner group 10. The hot water supply side primary heat exchanger 13 and the bath side primary heat exchanger 14 are arranged side by side in the left-right direction. Each heat exchanger 13, 14 comprises a plurality of fins 15 stacked at predetermined intervals in the front-rear direction, and a heat transfer tube 16 that penetrates each fin 15 in a serpentine manner.

[0020] (Secondary heat exchanger 4) The secondary heat exchanger 4 includes a hot water supply side secondary heat exchanger 17 located above the hot water supply side primary heat exchanger 13, and a bath side secondary heat exchanger 18 located above the bath side primary heat exchanger 14. The hot water supply side secondary heat exchanger 17 and the bath side secondary heat exchanger 18 are arranged side by side in the left-right direction. Each of the heat exchangers 17, 18 includes a plurality of heat transfer tubes 19 formed in a serpentine shape and stacked one above the other.

[0021] The secondary heat exchanger 4 and the primary heat exchanger 3 are connected by an exhaust guide path 20 for introducing the combustion gas that has passed through the primary heat exchanger 3 into the secondary heat exchanger 4. The exhaust guide path 20 guides the combustion gas that has passed through the primary heat exchanger 3 from the lower part to the rear part, and causes it to flow out from the rear surface of the upper casing 7 into the inside of the secondary heat exchanger 4. An exhaust port 21 is formed on the front surface of the upper casing 7 for exhausting the combustion gas that has flowed out into the inside of the secondary heat exchanger 4 to the outside.

[0022] As shown in Fig. 2, a water supply pipe 29 is connected to the inlet 22 of the heat transfer pipe 19 of the hot-water-supply-side secondary heat exchanger 17. As shown in Fig. 3, an outlet 54 of the heat transfer pipe 19 is connected to the inlet 23 of the heat transfer pipe 16 of the hot-water-supply-side primary heat exchanger 13 by a hot-water-supply-side relay pipe 55. As shown in Fig. 2, an outlet 24 of the heat transfer pipe 16 of the hot-water-supply-side primary heat exchanger 13 is connected to an outlet pipe 56.

[0023] As shown in Figure 3, a return pipe 57 from the bathtub is connected to the inlet 25 of the heat transfer tube 19 of the bath-side secondary heat exchanger 18. As shown in Figure 2, the outlet 26 of the heat transfer tube 19 is connected to the inlet 27 of the heat transfer tube 16 of the bath-side primary heat exchanger 14 by a bath-side relay pipe 58. The outlet 28 of the heat transfer tube 16 of the bath-side primary heat exchanger 14 is connected to the bathtub by a forward pipe 53.

[0024] (Partition member 30) As shown in Figs. 4 and 5, a partition member 30 is housed in the can body 8. The partition member 30 includes a lower partition member 31, a middle partition member 32, and an upper partition member 33. The partition member 30 extends in the front-rear direction. The lower partition member 31 is located between the first burner group 9 and the second burner group 10 in the lower casing 5. The middle partition member 32 is located between the hot water supply side primary heat exchanger 13 and the bath side primary heat exchanger 14 in the middle casing 6. The upper partition member 33 divides the exhaust guide passage 20 into left and right, and is located between the hot water supply side secondary heat exchanger 17 and the bath side secondary heat exchanger 18 in the upper casing 7.

[0025] The inside of the lower casing 5 of the burner section 2 is divided by the lower partition member 31 into a first combustion chamber 34 and a second combustion chamber 35. The inside of the middle casing 6 of the primary heat exchanger 3 is divided by the middle partition member 32 into a space accommodating the hot water supply side primary heat exchanger 13 and a space accommodating the bath side primary heat exchanger 14. The inside of the upper casing 7 of the secondary heat exchanger 4 is divided by the upper partition member 33 into a space accommodating the hot water supply side secondary heat exchanger 17 and a space accommodating the bath side secondary heat exchanger 18. Therefore, the inside of the can body 8 is divided by the partition member 30 into a space accommodating the first burner group 9, the hot water supply side primary heat exchanger 13, and the hot water supply side secondary heat exchanger 17, and a space accommodating the second burner group 10, the bath side primary heat exchanger 14, and the bath side secondary heat exchanger 18.

[0026] As shown in Figs. 1 and 5, an air supply chamber 36 is formed in the lower part of the lower casing 5. An air supply fan 37 is connected to the lower end of the air supply chamber 36. A distribution plate 38 is disposed between the first burner group 9 and the second burner group 10 and the air supply chamber 36 to separate them. A plurality of cooling air through holes (hereinafter sometimes simply referred to as "through holes") 39 are formed in the distribution plate 38. Combustion air sent from the air supply fan 37 is adapted to be supplied to each combustion chamber 34, 35 through the through holes 39 in the distribution plate 38.

[0027] A receiving portion 40 having a U-shaped cross section is formed at the upper end of the lower partition member 31. A V-shaped insertion portion 41 is formed at the lower end of the middle partition member 32. When the burner section 2 and the primary heat exchanger 3 are assembled, the insertion portion 41 of the middle partition member 32 is inserted into the receiving portion 40 of the lower partition member 31, so that both partition members 31 and 32 are connected. In addition, when the primary heat exchanger 3 and the secondary heat exchanger 4 are assembled, the lower end of the upper partition member 33 is located within the exhaust guide passage 20 and can abut against the upper end of the middle partition member 32.

[0028] (Lower partition member 31) As shown in FIG. 6, the lower partition member 31 includes a middle plate 42 located in the center in the left-right direction, a left plate 43 located on the left side of the middle plate 42, and a right plate 44 located on the right side of the middle plate 42. The upper end of the middle plate 42 is located below the insertion portion 41 of the middle partition member 32. The lower end of the middle plate 42 is bent at a right angle and fixed on the distribution plate 38. The left plate 43 and the right plate 44 are arranged parallel to the middle plate 42 with a predetermined gap therebetween. The upper ends of the left plate 43 and the right plate 44 each constitute one side of the receiving portion 40. A heat-sensing rod 45 is held by the left and right side plates 43, 44 near the upper end of the middle plate 42. A temperature sensor (e.g., a thermistor) 46 attached to the front of the lower casing 5 is inserted into the heat-sensing rod 45 (see FIGS. 2 to 4). The temperature sensor 46 is connected to a controller (not shown) that controls the combustion of both burner groups 9, 10.

[0029] The lower portions of the left side plate 43 and the right side plate 44 include a horizontal plate portion 47 and a vertical plate portion 48. The horizontal plate portion 47 extends in a direction away from the middle plate 42 slightly below the upper end surface (combustion surface 67) of the adjacent burner unit 11. The vertical plate portion 48 extends downward so as to be parallel to the side surface of the burner unit 11. The vertical plate portion 48 and the horizontal plate portion 47 are integrally formed to form an air guide member 49 that is spaced wider from the middle plate 42 than the upper portions of the left side plate 43 and the right side plate 44. A pair of air guide members 49 are provided on both the left and right sides of the middle plate 42. Each air guide member 49 is provided at a height equal to or lower than the combustion surface 67 of each burner unit 11.

[0030] The lower end of the vertical plate portion 48 is located above the distribution plate 38. A gap 50 is formed between the lower end of the vertical plate portion 48 and the distribution plate 38 as a communication portion. A plurality of vent holes 51 are formed in the horizontal plate portion 47 of the air guide member 49 in a line in the front-rear direction. Combustion air supplied from the distribution plate 38 to the air guide member 49 is discharged upward from the vent holes 51. A gap 52 is formed between the vertical plate portion 48 of the air guide member 49 and the burner unit 11. The combustion air supplied from the distribution plate 38 that does not pass through the air guide member 49 passes through the gap 52 and is discharged upward.

[0031] (Distribution board 38) 9 and 10, the distribution plate 38 includes a plate-shaped main body 59, a pair of mounting portions 60 extending downward from both side edges of the main body 59, and a fixing portion 61 extending downward from the rear end of the main body 59. As shown in Fig. 5, the mounting portions 60 are placed on guide portions 62 formed to protrude inward from the inner surfaces of both the left and right sides of the lower casing 5. The fixing portion 61 is fastened to the rear wall of the lower casing 5 with a plurality of bolts 63.

[0032] The main body 59 has a plurality of through holes 39. The through holes 39 are configured to have a circular round hole 64, a non-burred hole 65 having a diameter larger than that of the round hole 64, and a burred hole 66 having the same shape as the non-burred hole 65 and a peripheral portion formed by burring into a cylindrical shape. The round holes 64 are arranged in a plurality of locations dispersed throughout the main body 59. Most of the plurality of round holes 64 are positioned between a pair of adjacent burner units 11 and arranged side by side in the front-rear direction.

[0033] As shown in Fig. 10, both the non-burring holes 65 and the burring holes 66 are formed in a flat shape (for example, an oval or elliptical shape) with a diameter in the front-to-rear direction shorter than the diameter in the left-to-right direction. Unlike the burring holes 66, the non-burring holes 65 are holes that do not have burring (a cylindrical raised portion). The non-burring holes 65 and the burring holes 66 are arranged alternately and aligned in a straight line in the front-to-rear direction.

[0034] 7 and 8, the non-burred holes 65 and the burred holes 66 are arranged below the bath side air guide member 49 of the pair of air guide members 49. Meanwhile, a plurality of round holes 64 are arranged in a zigzag pattern in the front-to-rear direction below the hot water supply side air guide member 49 of the pair of air guide members 49. The portion of the main body 59 corresponding to the pair of air guide members 49 is used as a cooling air supply section 68.

[0035] (Function and effect of the combustion device 1) When the hot water tap provided on the hot water outlet pipe 56 is opened to allow water to flow through the device, the water from the water supply pipe 29 passes through the heat transfer pipe 19 of the hot water supply side secondary heat exchanger 17, and then through the heat transfer pipe 16 of the hot water supply side primary heat exchanger 13. Meanwhile, the controller ignites the first burner group 9 and rotates the air supply fan 37 to supply combustion air from the air supply chamber 36 to the first burner group 9 through the distribution plate 38. The combustion gas from the first burner group 9 passes through the hot water supply side primary heat exchanger 13 and the hot water supply side secondary heat exchanger 17 in this order in the first combustion chamber 34, so that sensible heat is mainly recovered in the hot water supply side primary heat exchanger 13 and latent heat is mainly recovered in the hot water supply side secondary heat exchanger 17, and hot water at a predetermined temperature is discharged from the hot water outlet pipe 56.

[0036] On the other hand, when the reheating switch on the controller is turned on, the controller drives the pump installed in the circulation path between the bathtub and the second burner group 10 to ignite it, and rotates the air supply fan 37 to supply combustion air from the air supply chamber 36 to the second burner group 10 through the distribution plate 38. The hot water from the bathtub passes through the heat transfer tube 19 of the bath-side secondary heat exchanger 18, and then passes through the heat transfer tube 16 of the bath-side primary heat exchanger 14, and the combustion gas from the second burner group 10 passes through the bath-side primary heat exchanger 14 and the bath-side secondary heat exchanger 18 in that order within the second combustion chamber 35. Therefore, the bath-side primary heat exchanger 14 mainly recovers sensible heat, and the bath-side secondary heat exchanger 18 mainly recovers latent heat, and the hot water in the bathtub is reheated while circulating.

[0037] The combustion air as cooling air enters the air guide member 49 through the distribution plate 38 on the lower partition member 31 side, passes through the air guide member 49, and is discharged from the ventilation opening 51. At least a part of the cooling air through holes 39 is a burring hole 66 in which the peripheral portion of the through hole 39 rises cylindrically toward the air guide member 49 side, so that the air supplied from the air supply fan 37 is guided upward by the cylindrical rising portion when entering the air guide member 49. In addition, since the cooling air supply part 68 is located below the air guide member 49, the air can be efficiently supplied toward the inside of the air guide member 49. Therefore, the generation of turbulence in the air guide member 49 is suppressed, and the partition member 31 can be efficiently cooled.

[0038] In this way, the left and right side plates 43, 44 are cooled, so that the heat-sensing rod 45 and the temperature sensor 46 do not overheat. In particular, since the air guide member 49 communicates with the combustion chambers 34, 35 through the gap 50, the pressure of the air passing through the burner groups 9, 10 and the pressure of the air in the air guide member 49 become the same, and the air flow is stable, maintaining good combustion in the burner unit 11. Even if drainage generated in the secondary heat exchanger 4 falls and blocks the vent hole 51, the air in the air guide member 49 can flow to the combustion chambers 34, 35 side through the gap 52. Therefore, the combustion air of the burner unit 11 is secured, and good combustion is maintained.

[0039] If the combustion products adhere between the fins 15 of the primary heat exchangers 13, 14 and cause clogging of the fins 15, the air from the air guide member 49 cannot pass between the fins 15, the cooling effect of the left and right side plates 43, 44 decreases, the temperature of the left and right side plates 43, 44 rises, and the heat-sensing rod 45 and the temperature sensor 46 are overheated. When the temperature detected by the temperature sensor 46 reaches the set judgment temperature, the controller stops the combustion of the burner groups 9, 10 as fin blockage has occurred. Here, the air from the air guide member 49 maintains the combustion of the burner units 11 near the lower partition member 31, so that the temperature detected by the temperature sensor 46 is stable and the detection accuracy of fin blockage can be ensured.

[0040] In addition, if all the cooling air through holes 39 are burring holes 66, the peripheral portions of all the through holes 39 must be raised, so the number of burring holes 66 is limited, and it becomes difficult to supply cooling air sufficiently into the air guide member 49. For this reason, the non-burring holes 65 are arranged in such a manner that a plurality of non-burring holes 65 are located between a pair of burring holes 66 adjacent to each other in the front-rear direction. This ensures the number of cooling air through holes 39 and allows a sufficient amount of cooling air to be supplied into the air guide member 49, despite the presence of the burring holes 66. In addition, the air flow from the burring holes 66 can guide the air from the non-burring holes 65 upward, so that the generation of turbulence in the air guide member 49 can be prevented, and the partition member 30 can be efficiently cooled.

[0041] Furthermore, in order to increase the number of burring holes 66 arranged in the front-rear direction while taking into account the processing limits, it is desirable to reduce the front-rear diameter of the burring holes 66. However, simply reducing the front-rear diameter results in a corresponding decrease in the amount of air passing through the burring holes 66. Therefore, by making the burring holes 66 flat so that the front-rear diameter is shorter than the left-right diameter, the number of burring holes 66 can be increased and the amount of air can be secured.

[0042] (Other embodiments) The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0043] In the above embodiment, the burring hole 66 is formed by burring, but the manufacturing method of the burring hole 66 is not limited to burring. In short, the burring hole 66 is a hole having a rising portion that rises in a cylindrical shape from the periphery of the hole.

[0044] In the above embodiment, the burring holes 66 are arranged in a single row in the front-rear direction, but the number of rows of the burring holes 66 may be two or more.

[0045] In the above embodiment, an elongated burring hole 66 having a shorter diameter in the front-rear direction than in the left-right direction is exemplified. However, the burring hole may be a rectangular or diamond shaped burring hole whose dimension in the front-rear direction is shorter than its dimension in the left-right direction.

[0046] In addition, the number of burner units in the burner group, the shape of the partition member, the structure of the boiler body, etc. can be modified as appropriate, and the bath side primary and secondary heat exchangers are not limited to those for bath reheating, but may be incorporated into the heating circuit of a floor heating system, etc., or may not have a secondary heat exchanger for latent heat recovery. [Explanation of symbols]

[0047] 1: Combustion device 2: Burner section 3: Primary heat exchanger 4: Secondary heat exchanger 5: Lower casing 6: Middle casing 7: Upper casing 8: Boiler body 9: First burner group 10: Second burner group 11: Burner unit 12: Mixing tube 13: Hot water supply side primary heat exchanger 14: Bath side primary heat exchanger 15: Fin 16: Heat transfer tube 17: Hot water supply side secondary heat exchanger 18: Bath side secondary heat exchanger 19: Heat transfer tube 20: Exhaust guide path 21: Exhaust port 22: Inlet 23: Inlet 24: Outlet 25: Inlet 26: Outlet 27: Inlet 28: Outlet 29: Water supply pipe 30: Partition member 31: Lower partition member 32: Middle partition member 33: Upper partition member 34: First combustion chamber 35: Second combustion chamber 36: Air supply chamber 37: Air supply fan 38: Distribution plate 39: Through hole 40: Receiving portion 41: Insertion portion 42: Middle plate 43: Left side plate 44: Right side plate 45: Heat-sensing rod 46: Temperature sensor 47: Horizontal plate portion 48: Vertical plate portion 49: Air guide member 50: Gap 51: Vent 52: Gap 53: Supply pipe 54: Outlet 55: Hot water supply side relay pipe 56: Hot water outlet pipe 57: Return pipe 58: Bath side relay pipe 59: Main body portion 60: Mounting portion 61: Fixing portion 62: Guide portion 63: Bolt 64: Round hole 65: Non-burred hole 66: Burred hole 67: Combustion surface 68: Cooling air supply portion

Claims

1. A combustion device in which two combustion chambers are formed within a single can body with a partition member between them, a burner unit is disposed below each combustion chamber, and a heat exchanger is disposed above each of the combustion chambers, and an air supply chamber separated by a distribution plate having a plurality of through holes is formed below the two combustion chambers, and combustion air is supplied from the air supply chamber through the distribution plate to each of the combustion chambers by an air supply fan connected to the air supply chamber, so that fluid passing through each of the heat exchangers can be individually heated by the combustion gas of each burner unit, a combustion apparatus in which air guide members for guiding the combustion air supplied from the distribution plate in an upward direction along the partition member are provided on both sides of the partition member at a height below the combustion surface of each of the burner units, and the distribution plate is located below the pair of air guide members and has a cooling air supply section provided with a plurality of cooling air through holes for supplying the combustion air as cooling air into the air guide member, and at least some of the cooling air through holes are burring holes whose peripheral portions rise cylindrically toward the air guide member.

2. The partition member extends in the front-rear direction, 2. The combustion apparatus according to claim 1, wherein the plurality of cooling air through holes are composed of a plurality of the burring holes and a plurality of non-burring holes having no burring, and the plurality of non-burring holes include non-burring holes arranged in a manner such that they are located between a pair of the burring holes adjacent to each other in the front-rear direction.

3. 3. The combustion apparatus according to claim 1, wherein the burring hole has a flat shape in which a diameter in a front-rear direction is smaller than a diameter in a left-right direction.

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