JPH07119909A - Smoke tube boiler - Google Patents

Abstract

PURPOSE:To expedite heat transfer by a low-cost structure with low pressure loss. CONSTITUTION:A smoke tube boiler has at least one smoke tube 1, and a burner disposed oppositely to an inlet opening of the tube, and comprises an annular combustion gas passage 4 of a substantially circular section formed between an inner wall surface of the tube 1 and an outer periphery of a rodlike member 3. A heat transfer expediting unit 5 having a predetermined protruding height is provided on the outer periphery of the member 3. When combustion gas flows the passage 4 formed along the inner wall surface of the tube, a vortex flow is generated at a rear flow side of the unit by an operation of the unit protruding in the passage thereby to agitate the gas to improve heat transmission.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to improving heat transfer in a smoke tube boiler.

[0002]

2. Description of the Related Art Conventionally, a smoke tube boiler having a structure in which a large number of smoke tubes are arranged on the body of the boiler has been used. This smoke tube boiler is configured to flow combustion gas into the smoke tube to heat water around the smoke tube. However, in this smoke tube boiler, the heat transfer when the combustion gas flows through the smoke tube has not been sufficiently improved under the present circumstances.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to promote heat transfer in a smoke tube boiler with a low pressure loss and an inexpensive structure.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a structure in which at least one smoke pipe is provided, and a burner is arranged so as to face an inlet opening of the smoke pipe. In the boiler, a rod-shaped member is inserted into the smoke pipe, and an annular combustion gas passage having a substantially annular cross section is formed between the inner wall surface of the smoke pipe and the outer peripheral surface of the rod-shaped member, and the outer peripheral surface of the rod-shaped member is also formed. Is characterized in that a heat transfer promoting body having a predetermined protruding height is provided. Also,
The present invention is characterized in that, in the smoke tube boiler having the above-mentioned structure, the protruding height of the heat transfer promoting member is set to about 1/2 of the gap between the inner wall surface of the smoke tube and the outer peripheral surface of the rod-shaped member. The passage is provided at a portion where the combustion gas temperature is about 1000 ° C. or lower.

[0005]

When the combustion gas flows through the annular combustion gas passage formed along the inner wall surface of the smoke tube, the action of the heat transfer enhancer provided so as to project into the annular combustion gas passage causes the heat transfer enhancer to operate. A vortex is generated on the wake side to agitate the combustion gas, improving heat transfer.

[0006]

The preferred embodiments of the present invention will be described below. 1 and 2, the smoke tube boiler according to the present invention is configured by connecting a mixed gas cylinder (6), a combustion cylinder (7), a can body (8) and a chimney table (9). The mixed gas cylinder (6)
Is supplied with a premixed gas in which the fuel gas and the combustion air are premixed from the upstream side. The can body (8) is an outer cylinder (11),
It has tube sheets (12), (13) and a large number of smoke tubes (1) arranged between these tube sheets (12) and tube sheet (13). A liquid storage space (14) is formed between the outside of the smoke pipe (1) and the inside of the outer cylinder (11). The outer cylinder (11) has a liquid storage space (14) for water.
There are provided a water inlet (15) for supplying the hot water to the outside and a hot water outlet (16) for supplying the hot water from the liquid storage space (14) to the outside.

Burners (2) are arranged at the inlet openings of the smoke pipe (1) so as to face the respective inlet openings.
The structure of this burner (2) consists of one burner, and the burner combustion surface where the flame is formed is divided and arranged so as to face each inlet opening of the smoke tube (1). You can also do it.

A rod-shaped member (3) is inserted in the latter half of the smoke pipe (1), and an annular shape is provided between the outer peripheral surface of the rod-shaped member (3) and the inner wall surface of the smoke pipe (1). A combustion gas passage (4) is formed. A heat transfer promoting body (5) is provided on the outer peripheral surface of the rod-shaped member (3).

FIGS. 3 and 4 show a first embodiment of the essential part of the present invention. A rod-shaped member (3) is inserted in the smoke pipe (1), and a cross section is formed along the inner wall of the smoke pipe between the outer peripheral surface of the rod member (3) and the inner wall surface of the smoke pipe (1). A substantially annular annular combustion gas passage (4) is formed. The rod-shaped member
As the material (3), a solid material may be used, but in addition, a material in which the tip portion of the pipe is closed may be used. On the outer peripheral surface of the rod-shaped member (3), a heat transfer promoter having a predetermined protruding height with respect to the annular combustion gas passage (4).
(5) is provided. The protruding height of the heat transfer enhancer (5) is set to about 1/2 of the gap between the inner wall surface of the smoke pipe (1) and the outer peripheral surface of the rod-shaped member (3).

In the embodiment shown in FIGS. 3 and 4, the heat transfer enhancer (5) is formed by spirally winding a pipe or a round bar around the outer peripheral surface of the rod member (3). The spiral pitch of the heat transfer enhancer (5) is set so as to improve the heat transfer within a range where the pressure loss does not increase so much. In addition, the tip of the rod-shaped member (3), that is, the start of the annular combustion gas passage (4) is located where the temperature of the combustion gas (including combustion flame and gas during combustion reaction) is about 1000 ° C or less. It is arranged. By doing so, it is possible to secure a sufficient residence time of the combustion gas up to the tip of the rod-shaped member (3), that is, the start of the annular combustion gas passage (4), during which the combustion reaction is relatively high. It is performed in a high temperature region, and carbon monoxide (CO) can be suppressed from remaining. Also, as for the materials of the rod-shaped member (3) and the heat transfer promoter (5), inexpensive materials having relatively low heat resistance can be used.

FIG. 5 and FIG. 6 show a second embodiment of the essential part of the present invention. A rod-shaped member (3) is inserted in the smoke pipe (1), and a cross section is formed along the inner wall of the smoke pipe between the outer peripheral surface of the rod member (3) and the inner wall surface of the smoke pipe (1). A substantially annular annular combustion gas passage (4) is formed. The rod-shaped member
As the material (3), a solid material may be used, but in addition, a material in which the tip portion of the pipe is closed may be used. On the outer peripheral surface of the rod-shaped member (3), a heat transfer promoter having a predetermined protruding height with respect to the annular combustion gas passage (4).
(5) is provided. The protruding height of the heat transfer enhancer (5) is set to about 1/2 of the gap between the inner wall surface of the smoke pipe (1) and the outer peripheral surface of the rod-shaped member (3).

In the embodiment shown in FIGS. 5 and 6, the heat transfer enhancer (5) is formed by fixing a plurality of ring-shaped members to the outer peripheral surface of the rod-shaped member (3) at predetermined intervals. Has been done. The arrangement pitch of the heat transfer enhancers (5) is set so as to improve heat transfer within a range where the pressure loss does not increase so much.
Further, the tip of the rod-shaped member (3), that is, the start of the annular combustion gas passage (4) is located where the temperature of the combustion gas (including combustion flame and gas during combustion reaction) is about 1000 ° C or less. It is arranged. By doing so, it is possible to secure a sufficient residence time of the combustion gas up to the tip of the rod-shaped member (3), that is, the start of the annular combustion gas passage (4), during which the combustion reaction is relatively Performed in a high temperature range, carbon monoxide (C
O) can be suppressed from remaining. Also, a rod-shaped member
As for the material of (3) and the heat transfer promoter (5), inexpensive materials having relatively low heat resistance can be used.

FIGS. 7 and 8 show a third embodiment of the essential part of the present invention. A rod-shaped member (3) is inserted in the smoke pipe (1), and a cross section is formed along the inner wall of the smoke pipe between the outer peripheral surface of the rod member (3) and the inner wall surface of the smoke pipe (1). A substantially annular annular combustion gas passage (4) is formed. The rod-shaped member
As the material (3), a solid material may be used, but in addition, a material in which the tip portion of the pipe is closed may be used. On the outer peripheral surface of the rod-shaped member (3), a heat transfer promoter having a predetermined protruding height with respect to the annular combustion gas passage (4).
(5) is provided. The protruding height of the heat transfer enhancer (5) is set to about 1/2 of the gap between the inner wall surface of the smoke pipe (1) and the outer peripheral surface of the rod-shaped member (3).

In the embodiment shown in FIGS. 7 and 8, the heat transfer enhancer (5) has a plurality of spike-like protrusions fixed to the outer peripheral surface of the rod-like member (3) at predetermined intervals. It is configured.
The number and arrangement pitch of the heat transfer enhancers (5) are set so as to improve heat transfer within a range where pressure loss does not increase so much. Further, the tip of the rod-shaped member (3), that is, the start of the annular combustion gas passage (4), is
The temperature of the gas (including the gas in the combustion reaction) is about 1000 ° C. or lower. By doing so, it is possible to secure a sufficient residence time of the combustion gas up to the tip of the rod-shaped member (3), that is, the start of the annular combustion gas passage (4), during which the combustion reaction is relatively high. It is performed in a high temperature region, and carbon monoxide (CO) can be suppressed from remaining. Also, as for the materials of the rod-shaped member (3) and the heat transfer promoter (5), inexpensive materials having relatively low heat resistance can be used.

The operation of the above structure will be described. First, the premixed gas supplied to the mixed gas cylinder (6) is ejected from the burner (2) to form a flame. The flame is formed at the inlet opening of each smoke pipe (1). High-temperature combustion gas (including combustion flame and gas undergoing combustion reaction) generated by the combustion of the burner flows through the smoke pipe and is discharged to the outside of the system through the chimney table (9). During this time, the water flowing in from the water inlet (15) is heated by heat transfer from the smoke pipe in the liquid storage space (14) to become warm water, and then is supplied to the outside from the hot water outlet (16).

When the combustion gas flows in the smoke tube, the combustion gas flows into the annular combustion gas passage (4) from the middle of the flow.
When the combustion gas flows through the annular combustion gas passage (4), a vortex flow is generated on the wake side of the heat transfer promoting body, and the combustion gas is stirred. Therefore, the heat transfer from the combustion gas to the smoke pipe is significantly improved.

In the above description, the smoke tube boiler according to the present invention is described as a boiler for producing hot water.
By providing a vapor chamber above the liquid storage space (14),
It can also be used as a steam generation boiler.

[0018]

The present invention has the above-mentioned structure.
The combustion gas is made to circulate in an annular combustion gas passage formed along the inner wall surface of the smoke pipe, and the action of the heat transfer enhancer provided so as to project in the annular combustion gas passage causes the combustion gas to flow downstream from the heat transfer enhancer. It is possible to significantly improve heat transfer as compared with the conventional one by generating a vortex in the air and stirring the combustion gas. Moreover, it is possible to realize the above configuration with a low pressure loss and an inexpensive configuration, which is very effective in practice.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a smoke tube boiler according to the present invention.

FIG. 2 is an enlarged sectional view taken along line II-II in FIG.

FIG. 3 is an enlarged vertical sectional view showing a first embodiment of the main part of FIG.

4 is a sectional view taken along line IV-IV in FIG.

5 is an enlarged vertical sectional view showing a second embodiment of the main part of FIG.

6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 is a longitudinal sectional view showing a third embodiment of the main part of FIG. 1 in an enlarged manner.

8 is a sectional view taken along line VIII-VIII of FIG.

[Explanation of symbols]

 1 smoke pipe 2 burner 3 rod-shaped member 4 annular combustion gas passage 5 heat transfer accelerator

Claims (3)

[Claims] 1. A smoke tube boiler having at least one smoke tube (1), and a burner (2) disposed so as to face an inlet opening of the smoke tube, wherein a rod-shaped member (3) is provided inside the smoke tube (1). )
The inner wall surface of the smoke pipe (1) and the outer peripheral surface of the rod-shaped member (3), and an annular combustion gas passage (4) having a substantially annular cross section.
And a heat transfer enhancer (5) having a predetermined protruding height on the outer peripheral surface of the rod-shaped member (3). 2. The smoke tube boiler according to claim 1, wherein
A smoke tube boiler characterized in that the protruding height of the heat transfer enhancer (5) is set to about 1/2 of the gap between the inner wall surface of the smoke tube (1) and the outer peripheral surface of the rod-shaped member (3). 3. The smoke tube boiler according to claim 1, wherein:
A smoke tube boiler, wherein an annular combustion gas passage (4) is provided in a portion where the combustion gas temperature is about 1000 ° C or lower.