JP3007836B2 - Multi-tube once-through boiler - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a multi-tube once-through boiler in which a combustion gas passage is provided between an inner water pipe row and an outer water pipe row, and combustion gas flows in the combustion gas passage in a direction parallel to a pipe axis. It is about.

[0002]

2. Description of the Related Art Two rows of water pipes, an inner water pipe row and an outer water pipe row, connect an annular upper header and a lower header, and a smoke port is provided between an adjacent inner water pipe and an adjacent outer water pipe. By closing the pipe except for the end of the water pipe to be formed, a combustion gas passage is formed between the inner water pipe row and the outer water pipe row, and the combustion gas passage is formed by an inner smoke port provided at an end of the inner water pipe. A multi-tube once-through boiler is widely used which communicates with a flue through an outer smoke port provided at an end of an outer water pipe opposite to the inner smoke port in the pipe axis direction.

[0003] The boiler heats the water pipe facing the combustion chamber first by the flame generated in the combustion chamber surrounded by the inner water pipe row, and then passes through the inner smoke port into the combustion gas passage. Combustion gas is sent. When the combustion gas flows in the combustion gas passage parallel to the pipe axes of the inner and outer water pipes, the combustion gas heats the side of the inner water pipe row and the outer water pipe row facing the combustion gas passage, and the heated exhaust gas flows through the outer water pipe row. Emitted through chimney and flue. In this case, the inner water tube is heated strongly to directly receive the heat from the flame, but the outer water tube is not heated as much as the inside. In addition, although the amount of heat absorbed is increased by attaching various heat absorbing fins to the water pipe, the flow of combustion gas is hindered by attaching the heat absorbing fins, increasing pressure loss. In order to avoid this, the method of attaching the heat absorbing fin has been limited.

[0004]

The problem to be solved by the present invention is that after the combustion gas flows through a combustion gas passage provided between two inner and outer water pipe rows in parallel with the pipe axis of the water pipe. In a multi-tube once-through boiler configured to intersect with a water pipe,
An object of the present invention is to increase the heat absorption of the outer water pipe while suppressing an increase in pressure loss.

[0005]

An annular upper header and a lower header are connected by two rows of water pipes, an inner water pipe and an outer water pipe, and a smoke outlet portion is provided between adjacent water pipes of each water pipe row. By removing and closing, a combustion gas passage is formed between the inner water pipe row and the outer water pipe row, and the combustion gas passage communicates with a combustion chamber that performs combustion by an inner smoke port provided at an end of the inner water pipe, and the inner side. In a multi-tube once-through boiler that communicates a flue and a combustion gas passage with a flue for discharging combustion exhaust gas by an outer flue provided at an end of the outer water pipe opposite to the flue in the pipe axis direction, an outer flue of the outer flue. A thin plate-shaped heat absorbing horizontal fin perpendicular to the pipe axis direction of the water pipe, a combustion gas passage in which the combustion gas of the outer water pipe flows parallel to the pipe axis, and the temperature of the combustion gas flowing through the combustion gas passage is 600 parts. A thin plate for heat absorption parallel to the tube axis below the temperature Providing a fin.

[0006]

The heat absorbing fins provided in the combustion gas flow path are provided in parallel with the flow direction of the combustion gas in order to prevent an increase in pressure loss. In the case where a combustion gas passage is provided between the inner water pipe and the outer water pipe, and the combustion gas is caused to flow in the combustion gas passage in a direction parallel to the pipe axis, and then the combustion gas is caused to flow in a direction crossing the outer water pipe. Since the combustion gas flows in two directions, parallel and perpendicular to the tube axis direction, the portion where the heat absorbing fins are provided is limited. However, a heat absorbing fin parallel to the pipe axis direction is used in a portion where the combustion gas flows parallel to the pipe axis, and a heat absorbing fin perpendicular to the pipe axis direction in a portion where the combustion gas crosses the water pipe. By providing two types of heat absorbing fins in the water pipe, the flow of the combustion gas can always be prevented. If the temperature of the combustion gas is too high, the fins are overheated.
Provide only in the part lower than ℃.

[0007]

An embodiment of the present invention will be described with reference to the drawings.
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. An inner water pipe 3 and an outer water pipe 4 arranged in an annular shape between the upper and lower headers are connected to each other. Inner water pipe 3
In a portion other than the inner smoke outlet 5 and the outer smoke outlet 6 of the outer water pipe 4, the space between each adjacent water pipe is closed by a closing fin 8 parallel to the pipe axis direction. A combustion gas passage 7 is formed between 3 and the outer water pipe 4. A portion surrounded by the inner water pipe 3 is a combustion chamber 9, and a burner 10 is provided above the combustion chamber 9. The combustion chamber 9 and the combustion gas passage 7 are communicated with the upper part of the inner water pipe by the inner smoke port 5 without the closing fin 8, and the flue gas is discharged by the outer smoke port 6 without the closing fin 8 at the lower part of the outer water pipe. The flue 12 to be discharged and the combustion gas passage 7 are communicated. The surface of the outer water pipe 4 facing the combustion gas passage has a combustion gas temperature of 600.
A thin heat absorbing vertical fin 15 parallel to the pipe axis direction at a portion lower than ° C, and a thin heat absorbing horizontal piece perpendicular to the pipe axis direction at the outer smoke passage 6 of the outer water pipe 4. Fin 11
Are provided in large numbers. The upper and lower header portions are covered with a refractory material 14, and the entire can body is covered with a heat insulating material 15.

When the burner 10 is burned, 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 reaches the inside of the combustion gas passage 7 from the inside smoke passage 5 and flows from the upper part to the lower part in the combustion gas passage 7 to heat the inner water pipe 3 and the outer water pipe 4 facing the combustion gas passage 7. At this time, the heat of the combustion gas is absorbed into the outer water pipe 4 also through the heat absorbing vertical fins 15,
Since the heat absorbing vertical fins 15 are provided in parallel with the flow of the combustion gas, they do not cause much resistance. When the combustion gas reaches the outer smoke passage 6, the combustion gas flows across the outer water pipe from the combustion gas passage 7 to the flue 12. At this time, the heat of the combustion gas heats the horizontal fins 11 for heat absorption,
The outer water pipe 4 is heated through the horizontal fins 11 for heat absorption. However, since the horizontal fins 11 for heat absorption are provided in parallel with the flow of the combustion gas, the resistance is not so large. Inner water pipe 3
The water in the outer water pipe 4 is heated by heating the water pipe, becomes steam, and is taken out through the upper header 1, and the flue gas whose temperature has decreased is discharged through the flue 12.

[0009]

By implementing the present invention, the amount of heat absorbed by the outer water pipe can be increased while suppressing an increase in pressure loss, and the efficiency can be improved.

[Brief description of the drawings]

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

FIG. 2 is a sectional view taken along line AA of FIG. 1;

FIG. 3 is a partially enlarged view of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper header 2 Lower header 3 Inner water pipe 4 Outer water pipe 5 Inner smoke vent 6 Outer smoke vent 7 Burning gas passage 8 Closing fin 9 Combustion chamber 10 Burner 11 Heat absorption horizontal fin 12 Flue 13 Refractory material 14 Insulation material 15 Vertical fin for heat absorption

Claims (1)

(57) [Claims] 1. An annular upper header and a lower header are connected by two rows of water pipes, an inner water pipe and an outer water pipe, and the space between adjacent water pipes in each water pipe row is closed except for a smoke outlet portion. By that
Forming a combustion gas passage between the inner water pipe row and the outer water pipe row,
The combustion gas passage communicates with a combustion chamber that performs combustion by an inner smoke port provided at an end of the inner water pipe, and is combusted by an outer smoke port provided at an end of the outer water pipe opposite to the inner smoke port in the pipe axis direction. In a multi-tube once-through boiler that communicates a flue and a combustion gas passage that discharge exhaust gas, a thin plate-shaped heat absorbing horizontal fin that is perpendicular to the pipe axis direction of the water pipe is provided on the outer smoke port of the outer water pipe,
A thin plate-like heat parallel to the pipe axis direction is provided only on the portion of the outer water pipe on the combustion gas path side where the temperature of the combustion gas flowing through the combustion gas path is lower than 600 ° C. and the combustion gas flows parallel to the pipe axis. A multi-tube once-through boiler characterized by providing vertical fins for absorption.