JP2895785B2 - Flue of multi-tube once-through boiler - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-tube once-through boiler for heating a water pipe by flowing combustion gas in a flue formed between annularly arranged water pipes in parallel with the axis of the water pipe. It is about the road.

[0002]

2. Description of the Related Art As shown in FIG. 6, an annular upper header and a lower header are connected by a large number of water tubes arranged in a ring.
By connecting each adjacent water pipe with two fins 14 parallel to the water pipe axis, a flue parallel to the water pipe axis surrounded by the two water pipes and the two fins is provided between each water pipe. A boiler is known which has a configuration in which a combustion gas generated by performing combustion in a combustion chamber in the center of a can body is introduced into a flue and heated in a water pipe by flowing in parallel with a water pipe axis. . In the case of this boiler, it is necessary to connect two fins for each flue in order to form a flue, and each fin has two fins.
It is welded and fixed to the water pipe at the point.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a boiler in which a flue is provided between annularly arranged water pipes so that the flue can be easily formed. is there.

[0004]

SUMMARY OF THE INVENTION An annular upper header and a lower header are connected by a number of annularly arranged water pipes, and a flue parallel to the water pipe axis is formed between each adjacent water pipe. In addition, in a water pipe used for a boiler configured to flow combustion gas to a flue, each water pipe and adjacent water pipe circular arc portions of water pipes provided on the left and right sides thereof are each parallel to a water pipe axis curved toward the inside of the water pipe. A hollow is provided, and the water pipes are arranged closely so that the hollows face each other to form a flue surrounded by two water pipes between adjacent water pipes, and the inside of the flue burns parallel to the water pipes Let the gas flow.

[0005]

[Advantage] When adjacent water pipe arc portions of each water pipe are curved toward the inside of the water pipe, and provided with depressions in parallel with the water pipe axis, when the water pipes are closely arranged so that the depressions face each other, The recess forms a space between each water pipe parallel to the water pipe axis and surrounded by two water pipes. By flowing the combustion gas into the space surrounded by the water pipe, the water pipe can absorb the heat contained in the combustion gas and form a flue without providing fins that block between the water pipes Can be.

[0006]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an AA sectional view of a boiler according to one embodiment of the present invention,
2 is a front sectional view of a boiler according to one embodiment of the present invention, FIG. 3 is a sectional view taken along line BB of FIG. 2, FIG. 4 is a sectional view taken along line CC of FIG.
FIG. 5 is a schematic diagram of a water pipe used in one embodiment of the present invention. The water pipe 1 is connected to an annular upper header 7 and a lower header 8, and is arranged annularly so as to surround the combustion chamber 4. Each water pipe 1 is provided with two long concave portions 2 which are curved inward of the water pipe so as to be parallel to the water pipe axis, two places each.
The upper part of the water pipe has a depression extending toward the combustion chamber 4, and the lower part of the water pipe has a depression extending on the opposite side of the combustion chamber 4. The water pipes are arranged such that the depressions 2 face each other, and 2
A flue 3 surrounded by water tubes is formed. Each water pipe 1 is in contact with an adjacent water pipe at two points of a bent portion 13 which is a boundary with the concave portion 2 and is connected by welding. Above the combustion chamber 4, a combustion device 5 for forming a flame into the combustion chamber 4
Is provided. A flue inlet 6 connecting the combustion chamber 4 and the flue 3 is provided near the upper header 7 of the water pipe 1, and connecting the flue 3 and the exhaust gas discharge part 9 near the lower header 8 of the water pipe 1. A flue outlet 10 is provided. A steam pipe 12 is connected to the upper header 7, and a water supply pipe 11 is connected to the lower header 8, and water is supplied so that the water level in the water pipe 1 is constant.

When the combustion is performed by the combustion device 5 provided above the combustion chamber 4, the flame from the combustion device 5 heats the side of the water pipe 1 facing the combustion chamber 4 and generates high-temperature combustion gas. After the combustion gas flows along the surface of the water pipe 1 on the combustion chamber 4 side and heats the water pipe 1, the combustion gas is introduced into the flue 3 from the flue inlet 6 above the water pipe 1, and passes through the flue 3 from above. The water pipe 1 is heated from the side facing the flue 3 while flowing to the lower part. When the water pipe is heated, the water in the water pipe is also heated, and the water becomes steam and is taken out from the steam pipe 12. The combustion gas whose temperature has decreased by heating the water pipe 1 becomes exhaust gas,
The gas is sent to the exhaust gas discharge unit 9 through the flue outlet 10 and is exhausted.

[0008]

According to the present invention, the fins for connecting the water pipes, which have been required for forming the flue, are not required, and the number of welding points can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a boiler according to an embodiment of the present invention, taken along line AA.

FIG. 2 is a front sectional view of a boiler according to one embodiment of the present invention.

FIG. 3 is a sectional view of the boiler according to an embodiment of the present invention taken along line BB.

FIG. 4 is a sectional view of the boiler according to one embodiment of the present invention, taken along line CC.

FIG. 5 is a schematic diagram of a water pipe used in one embodiment of the present invention.

FIG. 6 is a sectional view of a conventional boiler.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water pipe 2 Depressed part 3 Flue 4 Combustion chamber 5 Combustion device 6 Flue inlet 7 Upper header 8 Lower header 9 Exhaust gas discharge part 10 Flue outlet part 11 Water supply pipe 12 Steam pipe 13 Bent part 14 Fin

Claims (1)

(57) [Claims] An annular upper header and a lower header are connected by a large number of annularly arranged water tubes, and a flue parallel to the water tube axis is formed between adjacent water tubes. In a water pipe used for a boiler having a configuration in which combustion gas flows through a flue, a concave part parallel to a water pipe axis is formed by bending each water pipe and adjacent water pipe arc portions of water pipes provided on the left and right thereof toward the inside of the water pipe. In addition, a flue of a multi-tube once-through boiler characterized by forming a flue surrounded by two water pipes between adjacent water pipes by arranging the water pipes closely so that the depressions face each other.