JPH1144401A - Boiler with heat absorbing fin intersecting combustion gas flow - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower pressure in a furnace by increasing a heat absorption amount of a heat absorbing fin and smoothly supplying combustion gas. SOLUTION: In the boiler in which water tube walls of two surfaces formed of a plurality of vertical water tubes 4 provided in parallel and blocking fins 8 for blocking between the plurality of vertical water tubes 4 are formed, a part sandwiched between the tube walls of the two surfaces is formed as a combustion gas passage and combustion gas flows in a vertical direction in the passage, many heat absorbing fins 11 of a fan blade shape slightly inclined from a vertical direction to a flowing direction of the gas in a direction intersecting a heat absorbing surface to combustion gas flow perpendicular to a water tube axis are provided on a part opposed to the passage of the tubes 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boiler provided with heat absorbing fins so that a heat absorbing surface crosses a combustion gas flow.

[0002]

2. Description of the Related Art When a combustion gas is caused to flow on the surface of a water pipe and heat of the combustion gas is absorbed by the water pipe, a heat absorbing fin may be provided on the surface of the water pipe in order to absorb more heat. When the heat absorbing surfaces of the heat absorbing fins are mounted so as to intersect with the flow of the combustion gas, the combustion gas is provided so as to vertically strike the heat absorbing fins as shown in FIG. It is designed to flow along the absorbing fins. By providing the heat absorbing fins on the surface of the water pipe, the amount of heat absorption can be increased as compared with the case without the heat absorbing fins, but it has been desired to further increase the amount of heat absorption. Further, when the combustion gas is caused to collide vertically with the heat absorbing fins, there is a problem that a combustion gas stagnation portion is formed at the collision portion, and the pressure in the furnace increases due to obstruction of the flow of the combustion gas. .

[0004]

The problem to be solved by the present invention is to increase the amount of heat absorbed by the heat absorbing fins and to prevent the pressure in the furnace from rising by smoothly flowing the combustion gas. is there.

[0005]

A water pipe wall comprising a plurality of vertical water pipes provided in parallel and a closing fin for closing between the water pipes is formed on two faces, and a portion sandwiched between the two water pipe walls. As a combustion gas passage, and in a boiler in which combustion gas flows vertically in the combustion gas passage, a heat absorption surface for the combustion gas flow is provided perpendicular to the water tube axis at a portion of the water tube facing the combustion gas passage. A large number of fan-shaped heat absorbing fins are provided in the direction intersecting and slightly inclined from the vertical with respect to the flow direction of the combustion gas.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a part of a water pipe in one embodiment, FIG. 3 is a longitudinal sectional view of a boiler embodying the present invention, and FIG. 4 is a sectional view taken along line AA of FIG. An annular upper header 1 is provided at the upper part of the can body, and an annular lower header 2 is also provided at the lower part. The inner water pipe 3 and the outer water pipe 4 are arranged in an annular shape between the upper and lower headers. The connection between the water pipe and the header is covered with a refractory material 13. The inner water pipe 3 and the outer water pipe 4 are portions other than the end of the water pipe where the inner smoke port 5 and the outer smoke port 6 are provided,
Each adjacent water pipe is closed by a closing fin 8 parallel to the pipe axis direction, and a combustion gas passage 7 is formed between the inner water pipe 3 and the outer water pipe 4. The central portion of the boiler surrounded by the inner water pipe 3 is a combustion chamber 9, and a burner 10 is provided above the combustion chamber 9. At the lower part of the inner water pipe, an inner smoke passage 5 having no closing fins 8 is provided so as to surround the combustion chamber 9. The combustion chamber 9 and the combustion gas passage 7 are connected by the inner smoke passage 5, Fin 8 for closing the upper part of the water pipe
The combustion exhaust gas sent through the combustion gas passage 7 by the outside smoke vent 6 not provided with the exhaust gas is discharged in the circumferential direction of the boiler, and thereafter discharged from the flue 12.

The water tube heat transfer surface, which is the surface of the outer water tube 4 facing the combustion gas passage, is surrounded by two arcs of concentric circles having different radii and the same arc angle, and two radii passing through both ends of each arc. The fan-shaped heat absorbing fins 11 are provided in multiple stages so that the fan-shaped heat absorbing surface intersects the combustion gas flow. The arc angle of the heat absorption fins 11 is smaller than half of the arc angle of the water pipe heat transfer surface, and the heat absorption fin rows provided with the heat absorption fins 11 in multiple stages are placed on the water pipe heat transfer surface of one water pipe. Are provided in parallel with each other, and a combustion gas main flow portion 14 which is a space without the heat absorbing fins 11 is provided between the two heat absorbing fin rows. The heat absorbing fins 11 are higher on the right side from the combustion gas passage 7 toward the outer water pipe 4 and are provided slightly inclined from perpendicular to the flow direction of the combustion gas. The inclination angle of the heat absorbing fins 11 is determined so as to be optimal for each boiler shape.

When the burner 10 is burned, high-temperature combustion gas is generated in the combustion chamber 9, and first, the surface of the inner water pipe 3 on the combustion chamber 9 side is heated. Subsequently, the combustion gas is supplied to the inner smoke vent 5
The inner water pipe 3 and the outer water pipe 4 heat the surfaces of the inner water pipe 3 and the outer water pipe 4 while flowing into the combustion gas passage 7 from the lower part to the upper part. At this time, the combustion gas flows through the combustion gas main flow portion 14, and the combustion gas that reaches the heat absorption fin row provided on the right side of the combustion gas main flow portion 14 flows along the heat absorption surface of the heat absorption fin 11. To the upper right.

When the heat absorbing fins 11 are provided perpendicular to the combustion gas flow, the combustion gas that has reached the heat absorbing fins 11 as shown in FIG. The amount of combustion gas that branches off into the flow returning to the main gas flow section and flows along the heat absorbing fins 11 is reduced by the amount returned to the main combustion gas flow section 14. However, when the heat absorbing fins 11 are inclined with respect to the combustion gas flow, the combustion gas that has reached the heat absorbing fins 11 as shown in FIG. Since it flows, a large amount of combustion gas flows along the heat absorbing fins 11. When the amount of combustion gas flowing along the heat absorbing fins 11 increases, the amount of heat absorbed by the heat absorbing fins 11 also increases, so that more heat is absorbed by the outer water pipe.

The combustion gas that has reached the heat absorbing fins 11 flows smoothly without stagnation because the heat absorbing fins 11 are inclined, and the resistance of the heat absorbing fins 11 is reduced by the heat absorbing fins 11. There are fewer fins than if the fins were perpendicular to the combustion gas flow.

The combustion gas flowing along the heat absorbing fins 11 also flows upward while performing heat exchange in the water pipe on the right side as well, and the combustion exhaust gas whose temperature has been reduced by heating the water pipe is discharged to the outside. It is discharged through the smoke vent 6 and the flue 12.

FIG. 2 shows another embodiment of the present invention. The heat absorbing fins 11 are slightly inclined from the vertical with respect to the direction of flow of the combustion gas by lowering the combustion gas main flow portion 14 and increasing the position as the distance from the left and right increases. The inclination directions of the fin rows are opposite to each other. Since the heat absorbing fins are slightly inclined from the direction perpendicular to the flow direction of the combustion gas, the combustion gas that has reached the heat absorbing fins 11 flows upward along the heat absorbing fins 11 to the left and right. This means that the heat absorbing fin 1 is the same as in FIG.
A lot of heat is absorbed in one.

[0013]

According to the present invention, the amount of heat absorbed by the water pipe can be increased. Further, the pressure loss due to the heat absorbing fins can be reduced, and the furnace pressure can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a heat absorbing fin obtained by extracting a part of an outer water pipe according to the present invention.

FIG. 2 is a perspective view of a heat absorbing fin in which a part of an outer water pipe is extracted in another embodiment.

FIG. 3 is a longitudinal sectional view showing one embodiment of the present invention.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is an explanatory view of a flow of a combustion gas in the case of a conventional heat absorbing fin.

[Explanation of symbols]

 REFERENCE SIGNS LIST 3 inner water pipe 4 outer water pipe 5 inner smoke port 6 outer smoke port 7 combustion gas passage 8 closing fin 9 combustion chamber 11 heat absorption fin 12 flue 14 main flow of combustion gas

Claims (3)

[Claims] 1. A water pipe wall comprising a plurality of vertical water pipes provided in parallel and a closing fin for closing between the water pipes is formed on two surfaces, and a portion sandwiched between the two water pipe walls is a combustion gas passage. In a boiler that allows the combustion gas to flow vertically in the combustion gas passage, the portion of the water tube facing the combustion gas passage is perpendicular to the water tube axis and the direction in which the heat absorption surface intersects the combustion gas flow. A plurality of fan-shaped heat absorbing fins which are slightly inclined from the vertical with respect to the flow direction of the combustion gas, wherein the heat absorbing fins intersect with the combustion gas flow. Boiler provided. 2. A heat absorbing fin array comprising a plurality of heat absorbing fins provided in each water pipe of a water pipe wall in the boiler provided with heat absorbing fins crossing the combustion gas flow according to claim 1. Wherein the two rows of heat absorbing fins are inclined in the same direction. The boiler provided with heat absorbing fins intersecting the combustion gas flow. 3. The heat absorbing fin array according to claim 1, wherein a plurality of heat absorbing fins are provided on each water pipe of the water pipe wall. Wherein the heat absorbing fins are arranged in two rows, and the two rows of the heat absorbing fins are inclined in opposite directions to each other.