JP2898748B2 - Multi-tube once-through boiler - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-tube once-through boiler of a type in which combustion gas flows through a plurality of water pipe groups in a cross-line direction.

[Conventional technology]

The can body of a multi-tube once-through boiler is generally the one shown in FIGS.
As shown in the figure, an annular upper header 1 'provided with a steam or hot water take-out portion and an annular lower header 2' provided with a water supply portion are arranged at a predetermined interval. It has a structure in which a drawer 1 'and a lower drawer 2' are communicatively connected by a plurality of vertical water pipes. The vertical water pipes are formed into an inner annular water pipe row 3 ′ and an outer annular water pipe row 4 ′, and a combustion chamber 6 ′ is provided inside the inner annular water pipe row 3 ′. A combustion gas passage 8 'is provided between the outer annular water pipe row 3' and the outer annular water pipe row 4 '.
Further, an opening 14 'is provided in the inner annular water pipe row 3' over the entire length of the water pipe so that the combustion chamber 6 'and the combustion gas passage 8' communicate with each other, and the outer annular water pipe row 4 'is connected to the outer annular water pipe row 4'. An opening 13 'is provided over the entire length of the water pipe so that the combustion gas passage 8' and the flue 12 'communicate with each other. This is because, in order to improve the combustion efficiency of the heating means such as the burner 7 ', it is considered that it is desirable to arrange the water pipe in an annular shape and make the inside thereof a combustion chamber 6'.

[Problems to be solved by the invention]

By the way, in the multi-tube once-through boiler having the above-described configuration, since the combustion chamber 6 'is provided inside the inner annular water pipe row 3', the can body becomes large, and the installation space for the boiler tends to be large. Has occurred.

An object of the present invention is to provide a can body structure in which the combustion chamber space is substantially reduced as described above, and to reduce the size of the boiler can body.

[Means for solving the problem]

The present invention has been made to solve the above-described problems, and includes an inner water pipe row and an outer water pipe row that form an annular shape,
A multi-tube recirculation boiler configured to circulate the combustion gas in the cross direction with respect to the water pipes of each of the water pipe rows, between the inner water pipe row and the outer water pipe row, and disposed close to the outside of the outer water pipe row. Forming a combustion gas passage through which the combustion flame and the combustion gas from the combustion burner flow to the flue inside the inner water pipe row, providing a heat transfer promoting fin on the inner surface of the inner water pipe row, A heat transfer enhancing fin is provided on an outer surface except for an upstream side of the combustion gas passage.

[Action]

The multi-tube type once-through boiler according to the present invention allows the combustion flame and the combustion gas from the combustion burner to flow in the cross direction with respect to the water pipes, guides the combustion flame to the gap between the inner water pipe row and the outer water pipe row, and effectively uses the gap space. Because it can be burned, in addition to the need for a large combustion chamber space as in the past, in addition to the fact that the temperature of the combustion flame and combustion gas is controlled by the water pipe, the generation of harmful combustion exhaust can be suppressed, The fuel can be completely burned from the can body inlet to the can body outlet.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic longitudinal sectional view showing an embodiment of a multi-tube once-through boiler according to the present invention, and FIG. 2 is a schematic transverse sectional view of FIG. In this embodiment, an annular upper header 1 provided with a steam or hot water outlet and an annular lower header 2 provided with a water supply are arranged at a predetermined interval, and an outer water pipe is provided. It is communicated by row 4 and inner water pipe row 3.

A gas shielding cover 6 is formed outside the outer water pipe row 4, and an all-primary air premixed combustion burner as a combustion burner 5 is fixed to one end of the gas shielding cover 6. The all-primary air premixed combustion burner 5 is a surface combustion burner, and supplies combustion flame and combustion gas in the cross direction to each of the water pipe rows 3 and 4. Is set equal to or less than a predetermined distance, for example, approximately three times the diameter d of the water pipe. Further, in the inner water pipe row 3 and the outer water pipe row 4, the water pipe closest to the combustion burner 5 is also set based on the predetermined distance as described above.

As shown in FIG. 2, the inner water pipe row 3 is provided with a gap of a predetermined width on the side facing the combustion burner 5, and each water pipe excluding this gap has closely adjacent ones. It is formed annularly in the state. A gas guide 7 is provided inside the inner water pipe row 3 with a predetermined gap therebetween, and a flue 8 is provided inside the guide 7.

Adjacent ones of the water pipes of the outer water pipe row 4 are connected by a fin-shaped member 9 and have a substantially annular shape.

Here, as shown in FIGS. 1 and 2, the inner water pipe row 3 is provided with a heat transfer enhancing fin 15 for improving heat transfer efficiency on a part of the inner surface and the outer surface of each water pipe. It is provided.

A partition portion 11 protruding from the gas guide 7 is provided between the outer surface of the gas guide 7 corresponding to the gap of the inner water tube row 3 and the water pipe 10 of the outer water pipe row 4. Thus, the inner water pipe row 3 is separated left and right at this portion, and a combustion gas passage 13 is formed between the outer water pipe row 4 and the inner water pipe row 3.

A portion of the gas guide 7 facing the combustion burner 5 has an opening 12 of a predetermined width on one side, through which the combustion gas passage 13 communicates with the flue 8. ing.

In the above configuration, the combustion air flows vertically from a blower (not shown) via a burner duct, and is supplied to the fuel burner 5 as premixed gas along with fuel gas from a gas supply nozzle on the way. At this time, the combustion air and the combustion gas have an air ratio of 1 or more (preferably 1) as described above.
~ 1.5) as a premixed gas.

Next, the premixed gas ejected from the combustion burner 5 is:
A flame is formed in front of the combustion burner 5, and the combustion gas passage 13
As shown by an arrow in FIG. 2, the gas flows from the can inlet port A ', which is one end of the pipe, to the right and left, passes between the outer water pipe row 4 and the inner water pipe row 3, and protrudes from the gas guide 7. The gas flows between the inner water pipe array 3 and the gas guide 7 to the can body outlet A ″ via the meandering flow path portion 14 and flows to the flue 8 from the opening 12. Since the combustion flame and the combustion gas from the combustion burner 5 are divided into right and left from the can body inlet A ′ and flow while flowing into the flue 8 from the can body outlet A ″ in two passes, the can body This means that the entire A was effectively used. For this reason, the conventional large combustion chamber becomes unnecessary. At this time, the heat transfer promoting fins 15 welded to the outside of the inner water pipe row 3 further enhance the heat transfer effect and perform an effective temperature control action, so that generation of harmful combustion exhaust is significantly suppressed.

The combustion flame and the combustion gas that have been completely burned in this way flow into the flue 8 from the left and right combustion gas passages 13 through the openings 12 and out of the exhaust stack (not shown).

Here, since the combustion burner 5 is an all-primary air premix burner, complete combustion is performed in a short time in the combustion gas passage, so that fuel costs can be saved.

Here, in the multi-tube once-through boiler according to the present invention,
If the combustion burner 5 is mounted on the opposite side of the position shown in the drawing and the outer water pipe row 4 is partitioned on the opposite side, the flow of the combustion gas can be reduced from two passes to three passes. Further, the arrangement of the water tubes is not limited to the above embodiment, and may be elliptical or square.

〔The invention's effect〕

As described above, according to the multi-tube once-through boiler according to the present invention, an independent combustion chamber such as a conventional boiler is not required, so that the can body can be made compact.

In addition, since the temperature of the combustion flame and combustion gas is controlled to a relatively low temperature range by each water pipe, and the generation of harmful combustion exhaust can be suppressed, special devices and structures for suppressing harmful exhaust as in the past are used. Becomes unnecessary, and cost reduction can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing an embodiment of a multi-tube once-through boiler according to the present invention, FIG. 2 is a schematic cross-sectional view of FIG. 1, and FIG. FIG. 4 is a schematic cross-sectional view of FIG. 3 showing an example of a once-through boiler. 3 ... inner water pipe row 4 ... outer water pipe row 5 ... combustion burner 6 ... gas shielding cover 7 ... gas guide 8 ... flue 13 ... combustion gas passage 14 ... meandering flow path section A …… Can body A ′ …… Can body entrance A ”…… Can body exit

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kazuhiro Ikeda 7 Horie-cho, Matsuyama-shi, Ehime Prefecture Examiner, Miura Industries Co., Ltd. Toshifumi Suzuki (56) ) Surveyed field (Int.Cl. ⁶ , DB name) F22B 21/06

Claims (1)

(57) [Claims] 1. A multi-tube once-through boiler comprising an annular inner water pipe row 3 and an outer water pipe row 4 and configured to flow combustion gas in the cross direction to the water pipes of each of the water pipe rows.
Between the inner water pipe row 3 and the outer water pipe row 4, the combustion flame and the combustion gas from the combustion burner 5 arranged close to the outside of the outer water pipe row 4 are passed through a flue 8 inside the inner water pipe row 3.
A heat transfer promoting fin 15 is provided on the inner surface of the inner water pipe row 3, and the combustion gas passage 13 is provided to the outer face of the inner water pipe row 3 excluding the upstream side of the combustion gas passage 13. A multi-tube once-through boiler provided with a heat promoting fin 15.