JPH0933002A - Can body structure of multitubular once-through boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the absorption efficiency of heat by a method wherein the inside diameter of the furnace wall of a combustion gas passage part is reduced lower than that of the furnace wall of a pass smoke port part. SOLUTION: An annular upper header 1 is arranged at the upper part of a can body and an annular header 2 at the lower part thereof, and the two headers are coupled together through a number of water tubes 3. The periphery of a water tube train arranged in an annular shape is covered with a cylindrical furnace wall 4 to form a combustion gas passage 7 running between the water tubes 3 and a furnace wall 4. A part surrounded with the water tubes 3 is a combustion chamber 9 and a burner 10 is arranged thereabove. In the inside diameter of the furnace wall 4, that of an upper part wherein a pass smoke port 5 is arranged is higher than that of a lower part and a distance between the water tube 3 of a combustion gas passage 7 and a furnace wall 4 is decreased. Combustion gas by a burner 10 flows through a gap between the water tubes of the pass smoke port part in a direction crossing the water tube and flows down in the direction of a combustion gas passage 7. In this case, the water tubes high-efficiently heats the water tubes by turbulence generated due to an uneven surface formed on the surface of the water tube.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a can body structure of a multi-tube once-through boiler in which combustion gas flows between a row of water tubes formed in an annular shape and a furnace wall in parallel with the water tubes.

[0002]

2. Description of the Related Art A large number of water pipes are connected between an annular upper header and a lower header, and a portion surrounded by the water pipes serves as a combustion chamber.
Except for the smoke vents, the gap between adjacent water pipes is closed, and the surroundings of the water pipe array are surrounded by a cylindrical furnace wall.The combustion gas generated by combustion in the combustion chamber burns the water pipes. A multi-tube once-through boiler is widely used in which the side facing the chamber is heated and then sent through a smoke outlet to a combustion gas passage formed between a water tube and a furnace wall, and is also heated from the outer surface of the row of water tubes.

[0003]

The problem to be solved by the present invention is to provide a can body structure capable of absorbing more heat in the boiler having the above construction.

[0004]

[Means for Solving the Problems] An annular upper pipe header and a lower pipe header are connected by a number of water pipes, and a portion surrounded by the water pipes serves as a combustion chamber. It has a structure in which the gap between the water pipes is closed and the circumference of the water pipe array is surrounded by a cylindrical furnace wall.The combustion gas generated by combustion in the combustion chamber heats the side of the water pipe facing the combustion chamber and then smokes it. In a multi-tube once-through boiler that sends heat through the mouth to the combustion gas passage formed between the water pipe and the furnace wall, and also heats from the outer surface of the water tube row, the combustion is more than the inner diameter of the furnace wall at the portion where the smoke passage is provided The inner diameter of the furnace wall in the gas passage portion is reduced, and the distance between the water pipe and the furnace wall in the combustion gas passage portion is narrowed.

[0005]

[Function] By providing a sufficient distance between the water pipe and the furnace wall in the smoke passage part, the combustion gas can flow in a direction intersecting with the water pipe, and in the combustion gas passage part where the combustion gas flows in parallel with the water pipe. Since the distance between the water pipe and the furnace wall is narrow, the combustion gas flows concentratedly on the water pipe surface, and if unevenness is provided on the water pipe surface, more heat can be absorbed by the generated turbulence, and the water pipe Can be efficiently heated.

[0006]

An embodiment of the present invention will be described with reference to the drawings.
An annular upper header 1 is provided on the upper part of the can body, and an annular lower header 2 is provided on the lower part as well, and a number of water pipes 3 are connected between the upper and lower headers. Bulge processing is applied to form irregularities in order to generate turbulence in the flow. Each water pipe 3 is closed between adjacent water pipes by a closing rod 8 parallel to the pipe axis direction, and the circumference of the annularly arranged water pipe row is covered with a cylindrical furnace wall 4 to form the water pipe 3 And furnace wall 4
A combustion gas passage 7 is formed between them. A portion surrounded by the water pipe 3 is a combustion chamber 9, and a burner 10 is provided above the combustion chamber 9. The upper part of the water pipe 3 is not blocked by the blocking rod 8,
The smoke chamber 5 connects the combustion chamber 9 and the combustion gas passage 7. The inner diameter of the furnace wall 4 is larger in the upper part with the smoke vent 5 than in the lower part, and the distance between the water pipe 3 of the combustion gas passage 7 and the furnace wall 4 is narrow. The combustion gas passage 7 is the flue 1 in the lower part of the combustion chamber.
2, the combustion exhaust gas is further exhausted through the chimney 6. The periphery of the furnace wall 4 is covered with a heat insulating material 11, and the lower part of the combustion chamber 9 is closed with a refractory material 13.

When the burner 10 is burned, combustion gas is generated in the combustion chamber 9, and first of all, the surface of the water pipe 3 on the combustion chamber 9 side is heated. The combustion gas flows through the water pipe gap at the smoke outlet in a direction intersecting with the water pipe, and flows downward toward the combustion gas passage 7. When the combustion gas reaches the narrow combustion gas passage 7 portion between the water pipe and the furnace wall, the combustion gas concentrates on the surface of the water pipe and efficiently heats the water pipe by the turbulent flow generated by the irregularities provided on the surface of the water pipe. The water in the water pipe is heated by heating the water pipe, becomes steam, and is taken out through the upper header 1. The flue gas whose temperature has dropped is discharged through the flue 12 and the chimney 6.

[0008]

By implementing the present invention, heat can be effectively absorbed from the combustion gas, and the heat absorption efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

[Explanation of symbols]

 1 Upper pipe head 2 Lower pipe head 3 Water pipe 4 Furnace wall 5 Smoke port 6 Chimney 7 Combustion gas passage 8 Closing rod 9 Combustion chamber 10 Burner 11 Insulation material 12 Flue 13 Refractory material

Claims (1)

[Claims] 1. An annular upper pipe header and a lower pipe header are connected by a number of water pipes, and a portion surrounded by the water pipes serves as a combustion chamber, and a gap between adjacent water pipes except for a smoke vent portion is closed. However, the structure in which the circumference of the water pipe array is surrounded by a cylindrical furnace wall, the combustion gas generated by performing combustion in the combustion chamber heats the side of the water pipe facing the combustion chamber, and then passes through the smoke vent to the water pipe. In a multi-tube once-through boiler that feeds to the combustion gas passage formed between the furnace walls and also heats from the outer surface of the water tube array, the combustion gas passage part A can body structure for a multi-tube once-through boiler, characterized in that the inner diameter of the furnace wall is reduced and the distance between the water pipe and the furnace wall in the combustion gas passage portion is narrowed.