TW202219432A - Combustion apparatus - Google Patents

Abstract

Provided is an air-suction type combustion apparatus, which is possible to suppress deterioration of combustion state and decrease in thermal efficiency, and to improve cooling of an outer wall of the combustion basket and the heat insulating plate to prevent overheating. The solution is to include: a heat insulating plate provided on the inner surface of the combustion basket having the combustion chamber in which the burner is accommodated; a combustion fan arranged on the downstream side in the flow direction of the combustion air discharge to constitute an air-suction type combustion apparatus; a closed space formed between the outer wall of the combustion basket and the heat insulating plate by bringing the heat insulating plate into abutting with the periphery of a partial region of the outer wall of the combustion basket; an air introduction hole provided for introducing air into the closed space; and an outflow opening unit arranged by which the air in the closed space flows out to the combustion chamber.

Description

burner

The present invention relates to a bleed combustion type combustion device in which a combustion fan for supplying combustion air to the burner is arranged in the flow direction of combustion exhaust gas generated from the burner downstream side.

It is conventionally known that a plurality of burners whose one direction is a long side are lined up in a direction perpendicular to the long side inside a quadrangular cylindrical combustion basket, and a gap exists on the inner surface of the outer wall of the combustion basket. On the other hand, a combustion apparatus provided with a heat shield (for example, refer to Patent Document 1). Among them, a combustion fan for supplying combustion air to the burner is arranged on the upstream side of the burner. [Prior Technology Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application No. 2016-125684 [Summary of Invention] [Problems to be solved by the invention]

However, in addition to the combustion device in which the combustion fan is arranged on the upstream side of the burner, there is also a so-called extraction combustion type combustion device in which the combustion fan is arranged on the downstream side of the burner.

When the combustion fan is disposed in the combustion device on the downstream side of the combustion chamber, the negative pressure acts uniformly on the entire combustion chamber inside the combustion basket. Accordingly, the cooling air cannot flow toward the outer wall of the combustion basket or the heat insulating plate, resulting in insufficient cooling, and the outer wall of the combustion basket and the heat insulating plate may be overheated.

Therefore, it is considered to increase the number of rotations of the combustion fan to increase the overall air volume. However, due to the supply of excess combustion air and the flow of a large amount of air, the combustion state may be deteriorated and the thermal efficiency may be lowered.

In view of the above-mentioned circumstances, the present invention is to provide a combustion device of the extraction combustion type, which can suppress the deterioration of the combustion state and reduce the thermal efficiency, and can promote the cooling of the outer wall of the combustion basket and the heat insulation plate to prevent overheating. for purpose. [means to solve the problem]

In order to achieve such an object, the present invention is a combustion device in which a heat shield is provided on an inner surface of a combustion basket, and a combustion fan for supplying combustion air to a burner is disposed on combustion exhaust gas generated from the burner An extraction combustion type combustion device on the downstream side in the flow direction of the flow direction, the combustion basket has a combustion chamber for accommodating the burner in the inside, and the combustion device is characterized by comprising: a closed space part, which is in contact with the above-mentioned heat insulation plate. around a part of the area of the outer wall of the combustion basket, and formed in the part of the area between the outer wall of the combustion basket and the heat insulating plate; the air introduction hole is formed in the outer wall of the combustion basket at the position where the closed space is formed, Air is introduced into the closed space; and an outflow opening is formed on the heat insulating plate at a position where the closed space is formed, and the air in the closed space flows out of the combustion chamber.

With the above configuration, the closed space formed by the partial region of the outer wall of the combustion basket and the heat insulating plate becomes fresh outside air and passes through the inside through the air introduction hole and the outflow opening. With the outside air at this time, the outer wall of the combustion basket and the heat shield in the position of the closed space portion are cooled.

A partial area of the outer wall of the combustion basket for forming the closed space portion can be set at a desired position. Furthermore, the surrounding of the closed space portion is closed by the contact between the outer wall of the combustion basket and the heat insulating plate. The closed space portion is cooled by introducing outside air expected to have a high cooling effect.

Thereby, for example, a closed space portion is provided in a place where the temperature becomes the highest among the outer walls of the heat insulating plate and the combustion basket, and this portion can be efficiently cooled with a small amount of outside air. Therefore, by introducing a relatively small amount of outside air (minimum necessary), the cooling can be concentrated at the most necessary location and cooling, so that the deterioration of the combustion state and the decrease in thermal efficiency caused by the introduction of the outside air can be minimized.

In addition, since the combustion apparatus of the present invention is a suction combustion type in which the combustion fan is installed downstream of the burner, the inside of the combustion basket becomes a negative pressure during the combustion of the burner. Thereby, the combustion exhaust gas does not leak from the air introduction hole to the outside of the combustion basket. Furthermore, by setting the size and number of the air introduction holes, etc., a desired amount of air can be introduced accurately.

As described above, according to the present invention, the deterioration of the combustion state and the influence on the reduction of thermal efficiency can be minimized, and sufficient cooling can be performed efficiently.

Moreover, as a specific aspect of the said closed space part, the heat insulating plate of the position corresponding to the said partial area is bulged toward the combustion chamber, and the outer wall of a combustion basket is brought into contact with the periphery of this bulging part.

As a more preferable aspect, the closed space portion is formed by a first convex portion bulging outward from the partial region of the outer wall of the combustion basket, and the first convex portion abutting against the outer wall of the combustion basket. It is characterized by that the said heat insulation board of the periphery is formed in the inside of the said 1st convex part.

Since the first convex portion constituting the closed space portion bulges toward the outside of the combustion basket, the closed space portion is formed at a position away from the flame of the burner, and is less susceptible to thermal influence of the flame of the burner.

Moreover, in this invention, it is characterized by that the said heat insulating board is provided with the 2nd convex part which bulged toward the inside of the said closed space part in the position corresponding to the said 1st convex part.

By providing the second convex portion in a shape that bulges toward the inside of the closed space portion, the heat insulating plate at the position of the closed space portion can be separated from the flame of the burner, and the overheating of the heat insulating plate can be further prevented.

Moreover, in this invention, it is characterized by that the said outflow opening part is formed in the downstream side rather than the said burner, and it is characterized by the downstream side rather than the said air introduction hole.

Thereby, the flow of the outside air from the air introduction hole into the closed space portion and the flow of the outside air from the outflow opening portion toward the combustion chamber can follow the flow of the combustion exhaust gas, and the flow of the outside air can be made efficient by the smooth flow of the outside air. Cool the outer wall of the combustion basket and the heat insulation board.

Further, in the present invention, the heat insulating plate is provided with an inclined piece, and the inclined piece is directed from the downstream end of the outflow opening to the upstream side in the closed space and toward the outer wall of the combustion basket. is characterized by the inclination of the direction.

The outside air entering the closed space from the air introduction hole and heading toward the outflow opening contacts the inclined fins, is guided, and flows into the combustion chamber from the outflow opening. The inclined piece is inclined toward the upstream side of the closed space portion and in a direction approaching the outer wall of the combustion basket. Thereby, the external air guided by the inclined fins and entering the combustion chamber makes an acute angle contact with the combustion exhaust gas flowing in the combustion chamber, and also flows along the heat insulating plate after entering the combustion chamber. Thereby, the heat insulating plate in the downstream side of the outflow opening can also be cooled.

In addition, in the present invention, a cladding plate is provided, the cladding plate is provided continuously with the heat insulating plate, is located on the upstream side of the closed space portion and on the downstream side of the burner, and covers the combustion The inner surface of the basket is characterized.

In the extraction combustion type combustion device, the combustion air is drawn by the fuel gas ejected from the flame port of the burner, and the turbulent flow generated by the vortex is prone to occur, and the combustion exhaust gas touches the outer wall of the combustion basket downstream of the burner, causing A condition where the outer walls of the combustion basket are overheated.

According to the present invention, by providing the cladding plate, even if the flow of the combustion exhaust gas is disturbed, the contact of the combustion air with the outer wall of the combustion basket can be prevented, and the temperature rise of the outer wall of the combustion basket can be suppressed.

An embodiment of the present invention will be described based on the drawings. The combustion apparatus of this embodiment is used as a heat source unit of a water heater, and as shown in FIG. 1 , includes a combustion basket 1 and a heat exchange basket 2 .

As shown in FIG. 2 , a combustion chamber 3 is formed inside the combustion basket 1 . Inside the combustion chamber 3, a plurality of burners 4 having flame ports 4a at the upper end are provided. Each burner 4 is formed in an elongated shape having a long side in one direction (referred to as the front-rear direction in the present embodiment), and the burners 4 are formed in a direction perpendicular to the long-side direction (referred to as the front-rear direction in the present embodiment). Horizontal) arrangement settings.

Inside the heat exchange basket 2, a heat exchanger 5 for supplying hot water to be heated is accommodated. A combustion fan (not shown) is connected to the upper part of the heat exchange basket 2 (the downstream side in the flow direction of the combustion exhaust gas).

The combustion fan forcibly flows the combustion exhaust gas generated by the combustion of the burner 4 in the discharge direction. At this time, the combustion chamber 3 becomes a negative pressure, and the combustion air is introduced from the outside into an air supply chamber (not shown) formed below the burner 4 . As described above, the combustion device of this embodiment is referred to as an extraction and combustion type combustion device because the air for combustion is supplied by the extraction air.

Between the burners 4 adjacent to each other, a ventable gap is formed. The air below each burner 4 is supplied to the burner 4 as secondary air when going toward the combustion chamber 3 from these gaps.

The combustion basket 1 is formed in a substantially rectangular cylindrical shape, and includes a pair of first combustion part outer walls 6 located on the front and rear sides and facing each other in a standing state, and a pair of second combustion parts located on the left and right sides and facing each other in a standing state. outer wall 7. The two first combustion portion outer walls 6 are positioned on the front and rear ends of each burner 4 , and the two second combustion portion outer walls 7 are positioned on the left and right sides of each burner 4 .

As shown in FIGS. 1 and 2 , a base end of an ignition electrode 8 for igniting the burner 4 and a frame rod 9 for detecting combustion of the burner 4 are supported on one of the first combustion portion outer walls 6 . base end.

The heat exchange basket 2 is formed in a substantially quadrangular cylindrical shape that is continuous with the combustion basket 1, and includes a first heat exchange portion outer wall 10 that is continuous and integral with the upper edge of the first combustion portion outer wall 6, and a second combustion portion outer wall that is connected to the second combustion portion outer wall. 7. The second heat-intersection outer wall 11 of the upper edge. The front and rear ends of the second heat exchange portion outer wall 11 are connected to the left and right ends of the first heat exchange portion outer wall 10 and are formed in a cylindrical shape. As shown in FIGS. 2 and 3 , the combustion chamber 3 is provided with a heat insulating plate 12 covering the inner surface of the first combustion portion outer wall 6 , and a cladding plate 13 continuous with the heat insulating plate 12 .

In a partial region of the first combustion portion outer wall 6 of the combustion basket 1, a first convex portion 14 that bulges outward is formed. The first convex portion 14 is located above the combustor 4 (downstream of the combustor 4 ), and the combustion chamber 3 side of the first convex portion 14 is covered by the heat insulating plate 12 . As shown in FIG. 3, the 1st convex part 14 is formed in a substantially square shape.

The heat insulating plate 12 is in contact with the periphery of the first convex portion 14 from the combustion chamber 3 side by covering the inner surface side of the first combustion portion outer wall 6 . Thereby, in the recess on the inner surface side of the first combustion portion outer wall 6 formed by the first convex portion 14 , there is formed a state where the outer periphery of the first convex portion 14 is closed by the heat insulating plate 12 . The closed space portion 15 (see FIG. 4 ).

The heat insulating board 12 in the position corresponding to the closed space part 15 is formed with the second convex part 16 bulging toward the inside of the closed space part 15 . The second convex portion 16 is formed in a substantially square shape slightly smaller than the first convex portion 14 . As shown in FIGS. 2 and 3 , the second convex portion 16 is a concave portion when viewed from the combustion chamber 3 side.

As shown in FIG. 1 , a plurality of air introduction holes 17 are formed in the first combustion portion outer wall 6 of the portion where the first convex portion 14 is formed. The air introduction hole 17 is provided so as to penetrate the first combustion part outer wall 6 to introduce the outside air into the closed space part 15 .

As shown in FIG. 3, the outflow opening part 18 is formed in the heat insulating board 12 in the position which covers the closed space part 15 above the 2nd convex part 16. As shown in FIG. The outflow opening portion 18 is provided so as to penetrate the heat insulating plate 12 to allow air to flow out from the closed space portion 15 into the combustion chamber 3 . The outflow opening portion 18 is disposed above the air introduction hole 17 (downstream in the flow direction of the combustion exhaust gas).

Moreover, as shown in FIG. 4, the inclined piece 19 is provided in the upper edge of the outflow opening part 18. As shown in FIG. When the outflow opening 18 is cut out from the heat insulating plate 12 , the heat insulating plate 12 at the position corresponding to the outflow opening 18 is bent and separated from the inside of the closed space portion 15 , so that the outflow opening 18 can be simultaneously separated. The inclined piece 19 is formed. If the outflow opening 18 has a horizontally long shape, the inclined piece 19 can also be formed into a horizontally long shape. Therefore, the inclined piece 19 acts like a reinforcing rib to increase the strength of the heat insulating panel 12 .

The closed space part 15 is formed by the first combustion part outer wall 6 and the heat insulation plate 12, and the external air passes through the inside of the closed space part 15 through the air introduction hole 17 and the outflow opening part 18, thereby cooling to form the closed space part 15 The part of the first combustion part outer wall 6 and the heat insulation board 12. That is, the part in which the closed space part 15 is provided can be cooled emphatically.

As described above, the combustion device of this embodiment adopts the extraction combustion type. Since the hot water supply device of the extraction and combustion type is used, the combustion chamber 3 becomes a negative pressure during the combustion operation (during the operation of the combustion fan). Therefore, since the flow from the air introduction hole 17 to the outflow opening 18 occurs in the closed space portion 15 , the combustion exhaust gas in the combustion chamber 3 does not leak from the air introduction hole 17 .

The closed space portion 15 can be appropriately sized by the first convex portion 14 and the heat insulating plate 12 , and the amount of air introduced into the closed space portion 15 can be easily set by the size and number of the air introduction holes 17 . Furthermore, as long as the closed space portion 15 is provided at a desired position of the first combustion portion outer wall 6, this position can be cooled with emphasis.

Therefore, the closed space portion 15 is provided in the portion of the first combustion portion outer wall 6 where the temperature becomes the highest, and the introduction amount of air from the air introduction hole 17 is set to the minimum amount necessary for cooling. By doing so, it is possible to efficiently cool the first combustion portion outer wall 6 and the heat insulating plate 12 while suppressing a small amount of air from the outside flowing into the combustion chamber 3 .

Furthermore, when the air introduced into the closed space portion 15 is directed toward the combustion chamber 3 from the outflow opening portion 18 , it contacts the inclined piece 19 provided along the upper edge of the outflow opening portion 18 and is guided obliquely upward. Thereby, the air that has entered the combustion chamber 3 from the closed space portion 15 can flow between the combustion exhaust gas and the heat insulating plate 12 in parallel with the flow of the combustion exhaust gas flowing in the combustion chamber 3, and the heat insulation can be suppressed. The temperature of the plate 12 rises.

The cladding plate 13 is provided at a position below the first convex portion 14 and above the burner 4 (on the upstream side in the flow direction of the combustion exhaust gas from the first convex portion 14 and above the combustion exhaust gas from the burner 4 ). the downstream side of the flow direction).

As shown in FIG. 3 , the cladding plate 13 is provided with a blocking portion 20 for blocking a space between the cladding plate 13 and the first combustion portion outer wall 6 at the lower end portion thereof. The blocking portion 20 prevents air from entering between the cladding plate 13 and the first combustion portion outer wall 6 . On the other hand, the blocking part 20 provided in the lower end of the cladding plate 13 guides the air between the cladding plate 13 and the burner 4 .

Thereby, by the air curtain effect of the air passing between the cladding plate 13 and the burner 4, the flame of the burner 4 can be prevented from falling in the direction of the cladding plate 13 and the heat insulating plate 12, and the cladding can be suppressed. Overheating of the plate 13 and the heat insulation plate 12 .

In addition, in this embodiment, although the example in which the 2nd convex part 16 which has the substantially square flat surface which opposes the 1st convex part 14 is provided in the heat insulating board 12 is shown, the 2nd convex part 16 of this invention is The convex portion is not limited to the shape shown in this embodiment.

For example, as shown in FIG. 5 , a plurality of elongated groove-shaped portions 21 (non-penetrating) extending in the vertical direction may be formed on the substantially rectangular surface of the second convex portion 16 of the heat insulating plate 12 to exist with each other. The predetermined intervals are formed by arranging a plurality of them in the lateral direction. Thereby, the substantial surface area of the 2nd convex part 16 provided in a relatively narrow range can be made large, and the cooling effect of the heat insulating board 12 can be improved.

Also, in the present embodiment, a combustion device in which the combustion fan is arranged above and the combustion exhaust gas flows from below to above in the combustion chamber 3 (the heat exchange basket 2 is provided on the upper part of the combustion basket 1) is exemplified. However, the present invention can be suitably used even in a combustion device in which the combustion fan is arranged below and the combustion exhaust gas flows from above to below in the combustion chamber (the configuration in which the present embodiment is reversed up and down). used and the same effect can be obtained.

1: burning basket 2: heat exchange basket 3: Combustion chamber 4: Burner 4a: Flame mouth 5: heat exchanger 6: Outer wall (outer wall of the first combustion section) 7: Outer wall of the second combustion section 8: Ignition electrode 9: Frame rod 10: The outer wall of the 1st hot exchange 11: The outer wall of the second hot exchange 12: Insulation board 13: Cladding 14: 1st convex part 15: Enclosed Space Department 16: Second convex part 17: Air inlet hole 18: Outflow opening 19: Tilt piece 20: Occlusion Department 21: Groove

FIG. 1 is an explanatory perspective view showing a main part of a combustion apparatus according to an embodiment of the present invention. FIG. 2 is an explanatory cross-sectional view of the combustion basket and the heat exchange basket in the combustion apparatus of the present embodiment. FIG. 3 is an explanatory perspective view showing a heat shield. FIG. 4 is an explanatory cross-sectional view showing a closed space portion. FIG. 5 is an explanatory perspective view showing a modification of the second convex portion. [Types for carrying out the invention]

1: burning basket

2: heat exchange basket

3: Combustion chamber

4: Burner

4a: Flame mouth

5: heat exchanger

6: Outer wall (outer wall of the first combustion section)

8: Ignition electrode

9: Frame rod

10: The outer wall of the 1st hot exchange

12: Insulation board

13: Cladding

14: 1st convex part

15: Enclosed Space Department

16: Second convex part

20: Occlusion Department

Claims (6)

A combustion device is provided with a heat insulating plate on the inner surface of a combustion basket, and a combustion fan for supplying combustion air to a burner is arranged on the downstream side in the flow direction of combustion exhaust gas generated by the burner for extraction and combustion. A type of combustion device, the combustion basket has a combustion chamber for accommodating the burner inside, and the combustion device is characterized by comprising: The closed space portion is formed in the part of the region between the outer wall of the combustion basket and the heat-insulating plate by the heat-insulating plate abutting on the periphery of a part of the region of the outer wall of the combustion-basket; an air introduction hole formed in the outer wall of the combustion basket at a position where the closed space portion is formed, to introduce air into the closed space portion; and The outflow opening is formed in the heat insulating plate at the position where the closed space is formed, and allows the air in the closed space to flow out into the combustion chamber. The combustion apparatus according to claim 1, wherein the closed space portion includes a first convex portion bulging outward from the partial region of the outer wall of the combustion basket, and the first convex portion abutting against the outer wall of the combustion basket The said heat insulation board of the periphery is formed in the inside of the said 1st convex part. The combustion apparatus according to claim 2, wherein the heat insulating plate includes a second convex portion bulging toward the inside of the closed space portion at a position corresponding to the first convex portion. The combustion apparatus according to any one of claims 1 to 3, wherein the outflow opening is formed on the downstream side of the burner and on the downstream side of the air introduction hole. The combustion device according to any one of claims 1 to 3, wherein the heat insulating plate is provided with inclined fins, and the inclined fins extend from the downstream end of the outflow opening to the upstream side in the closed space, and toward the closed space. The direction approaching the outer wall of the aforementioned combustion basket is inclined. The combustion apparatus according to any one of claims 1 to 3, comprising a cladding plate, the cladding plate being provided continuously to the heat insulating plate, and located on the upstream side of the closed space portion and downstream of the burner side and cover the inner surface of the aforementioned combustion basket.

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