KR910001630Y1 - Tube fin for once through boiler - Google Patents

Abstract

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Description

Structure of the heat conduction plane of a multi-tubular once-through boiler

1 is a longitudinal sectional view of a boiler.

2 is a cross-sectional view taken along the line II-II of FIG.

3 is a main side view of FIG.

4 is a cross-sectional view taken along the line IV-IV of FIG.

5 is an exploded view of the combustion gas passageway of FIG.

6 is a conventional boiler longitudinal section.

7 is a main cross-sectional view of FIG.

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

9 is an exploded view of the combustion gas passage of FIG.

* Explanation of symbols for main parts of the drawings

1: upper tube support 2: lower tube support

3: inner annular water pipe row 4: outer annular water pipe row

5: combustion gas passage 6: combustion apparatus

7: combustion chamber 8: outer wall of the boiler

9: open place 10: open place

11: Smoke passage 12: Fin on plate

13: Slit

The present invention relates to the improvement of the dry heat sink structure of a boiler and to the structure of a heat conducting plane having an effective fin (F1N) used in a multi-tubular perfusion boiler.

Generally, a fin (FIN) is installed on the heat conduction surface of a boiler to promote heat transfer.

The same applies to the multi-tubular current boiler, and as shown in FIG. 6 (long sectional view) and FIG. 7 (main part side view of FIG. 6) for the purpose of improving the heat conduction efficiency, the flat fin FlN is used as the combustion gas. The method of providing parallel to the flow direction of is adopted.

That is, in the conventional method, the upper tube support 1 and the lower tube support 2 are formed together in an annular shape, and the upper and lower pipe supports 1 and 2 are connected to a plurality of water pipes so that these water pipes are radially spaced apart. A combustion gas cylinder is formed between two concentric annular water pipe rows (3) (4) and arranged between the inner annular water pipe rows (3) and the outer annular water pipe rows (4). A furnace 5 is formed and an open annular opening 9 of the entire length of the pipe is formed in the inner annular water pipe row 3 to connect the combustion chamber 7 and the combustion gas passage 5 to form an outer annular water pipe row. An open portion 10 is formed at the entire length of the pipe at 4 to connect the combustion gas passage 5 and the smoke passage 11 to the portion of the annular water pipe heading toward the combustion gas passage 5. In the circumferential direction, a plurality of flat fins 12 are installed in the circumferential direction over the entire length. Heat-exchange with the annular water pipe row 3 on the side, split toward the open portion 9 from the combustion chamber 7, flow into the combustion gas passage 5, and join in the open portion 10, from the smoke passage 11. It is discharged to the outside.

Since the conventional method is configured in this manner, the combustion gas passage 5 is formed to increase the area of the fin FlN to improve the heat conduction efficiency, and the entire length of the tube is formed in the inner annular water pipe row 3. An open place 9 is formed to connect the combustion chamber 7 and the combustion gas passage 5 to form an open place 10 over the entire length of the pipe in the outer annular water pipe row 4 to form the combustion gas passage ( 5) and a plurality of fins (FlN) 12 such as flat plates are installed in the circumferential direction over the entire length of the water pipe at the part facing the combustion gas passage 5 of the annular water pipe line by connecting the smoke passage 11 with the smoke passage 11. As a result, the combustion gas generated in the combustion chamber 7 is first heat-exchanged with the annular water pipe heat 3 by radiant heat, and is ground toward the open area 9 from the combustion chamber 7 so that the combustion gas flows into the combustion gas passage 5. The flow is joined to the open place 10 and is discharged to the outside from the smoke passage (11).

Since the conventional method is configured in this manner, the pressure loss of the combustion gas is reduced as the area of the fin FIN is increased to improve the thermal conductivity efficiency. However, according to this conventional method, since the plate-like fin FlN is arranged in a multi-tubular manner in parallel to the circumferential direction of the water pipe, the number of fins is extremely high and the number of fins for the water pipe is extremely high. The drawback was that the length of the weld was too long, resulting in a structure with a high cost thermally conductive surface.

That is, when the pins are welded to the water pipe and the spacing between the adjacent fins FlN is too narrow, the welding operation by the welder cannot be performed easily, so the spacing between the adjacent fins FlN can be performed. Although there should be an interval of a degree, since the length of a water pipe is limited, there exists a problem that the range which can install the maximum number of fins FIN within this limited length has to be limited.

In addition, increasing the number of fins on the heat conduction plane also increases the ventilation resistance of the combustion gas flowing on the heat conduction plane.

Therefore, when the ventilation resistance is increased, there is a need to use a blower capable of supplying a large amount of blowing air in proportion to this, thereby increasing the cost of the entire boiler.

Therefore, the problem is that the number of pins installed per pipe can not make this extremely high. As a result of diligent research, the following problems were identified.

In other words. In this conventional method, when the flow of combustion gas is seen, the smoke passage of the connecting portion of the combustion gas passage cannot be enlarged due to the relationship between the boiler installation spaces, and thus the development of the combustion gas passage of FIG. 9 depends on the momentum of the combustion gas. Since the non-mainstream area (L part) is formed in which the flow rate of the combustion gas is extremely lower in the H part region, the heat transfer effect can be excellent in accordance with the heat transfer effect of the fin (FlN). This extremely small amount does not contribute enough to the heat conduction zone, and the fins in this zone only contribute to the higher price of the boiler.

On the other hand, the fin FIN in the H portion region has a structure in which the flat fin FIN is arranged in the circumferential direction and the flow direction of the combustion gas increases the length of the fin FIN. Leading edge effect using high heat transfer Is only formed at the tip of the fin, so there is a limit to the improvement of the thermal conductivity.

In addition, heat stress due to the temperature difference between the fin FlN and the water pipe is generated, which may cause cracks in the pipe wall due to the heat stress.

The present invention has been devised in view of the above circumstances, and its purpose is to provide an array structure of fins (FIN) capable of effectively conducting heat transfer and to induce a leading etch effect using high heat transfer in the temperature boundary layer development region. It also prevents the occurrence of thermal stress due to the temperature difference between the fin (FlN) and the water pipe, and the thermoelectricity of the multi-tubular perfusion boiler by two rows of water pipes in which the pipe wall is provided with a flat fin (FlN) to prevent cracking. It is to provide a structure of the drawings.

In order to achieve the above object, in the present invention, the upper tube bottom and the lower tube bottom are formed together in an annular shape, and the upper and lower pipe supports are connected by a plurality of water pipes, and the water pipes are radially spaced in two concentric circles. Arranged to form annular water pipe rows, and forming combustion chambers in the inner annular water pipe rows to form annular combustion gases by internal and external water pipe rows, and forming an open point for the outer annular combustion gas passage in the inner water pipe rows. In the outer water pipe row, open holes are connected to the smoke passages installed on the outer wall of the boiler, and the flat fins (FlN) are arranged in multistage on the outer surface of the water pipe facing the combustion gas passage in the direction of the tube axis. In a multi-tubular boiler, the diameter of the flat pin is based on the horizontal plane including the central extension line (ℓ) of the smoke passage. On the end portion of the downstream-side pin along the flowing direction of the combustion gas is characterized in that the reuk configuration so far away than the end portion of the upstream-side pin.

FIG. 1 is a longitudinal sectional view of a multi-tubular perfusion boiler, FIG. 2 is a II-II cross-sectional view of FIG. 1, FIG. 3 is an enlarged view of a water pipe provided with a fin, and FIG. 4 is a IV-IV cross-sectional view of FIG. 5 is a development of the passage of the combustion gas.

In the figure, the upper tube support 1 and the lower tube support 2 are both formed in an annular shape.

The upper and lower pipe holders 1 and 2 are connected as vertical heat pipes as heat conduction pipes, and these water pipes are arranged as two concentric circular water pipe rows spaced radially apart.

A combustion gas passage 5 is formed between the inner annular water pipe row 3 and the outer water pipe wall 4.

The combustion device 6 is provided inside the upper tube support 1.

(7) is a combustion chamber formed inside the annular water pipe train 3 inside. Both ends of each of the annular water pipe rows 3 and 4 become narrow portions and are welded by being inserted into the pipe plate of the upper pipe support 1 and the pipe plate of the lower pipe support 2, respectively.

The boiler outer wall which surrounds the outer annular water pipe row 4 is formed.

The open part 9 is formed in the inner annular water pipe row 3 over the entire length of the pipe, and the combustion chamber 7 and the combustion gas passage 5 are connected.

On the outer surface of the water pipe facing the combustion gas passage 5, a flat fin (FIN) 12 is provided in multiple stages in the observation direction in each water pipe with an inclined surface with respect to the combustion gas flow A direction.

The inclined surface of the flat plate pin described above is such that the downstream pin end is located farther from the upstream pin end in accordance with the flow direction of the combustion gas when the horizontal plane including the central extension line 1 of the smoke passage is referenced.

These flat fins are constructed so that the angle of the inclined planes is opposed to the vertical plane including the center extension line (ℓ) of the smoke passage so that the combustion gas can be led to the upper portion of the combustion gas passage far away from the smoke passage. .

In addition, it is preferable to provide an appropriate number of slits 13 having a required width and length in a direction substantially perpendicular to the flow of the combustion gas on the flat fin FIN.

Referring to the effect of the present invention configured as described above are as follows.

The combustion gas generated in the combustion chamber 7 first exchanges heat with the annular water pipe heat 3 inside by radiant heat, and splits from the combustion chamber 7 toward the open portion 9 to reach the combustion gas passage 5. The heat exchange is performed mainly by convective heat conduction, and joins in the open place 10, and is discharged to the outside at a low temperature from the smoke passage 11.

At this time, the combustion gas flows linearly due to the momentum of the combustion gas, but in the present invention, as described above, the combustion gas is forcibly guided to the upper portion of the combustion gas passage since the fin F is inclined. The mainstream region H of the combustion gas passage contributing to the heat conduction (marked with oblique lines in the drawing) is significantly enlarged compared to the conventional structure, as shown in FIG. 5, so that the surface of almost all water pipes facing the combustion gas passage is convection. It contributes to the heat conduction surface of, and the non-mainstream region (convection zone) b of the combustion gas is greatly reduced, and as a result, the heat conduction efficiency is greatly improved.

In addition, since the fin FIN is provided in a direction substantially intersecting with the combustion gas flow, the plate fin FIN is slit with a heat transfer effect using high heat transfer in the temperature boundary layer development region. It is formed every groove 13 so that the conduction efficiency is further improved.

By providing the slit 13, the difference in thermal expansion between the plate fin FlN and the water pipe as a main factor is absorbed and relaxed as the slit 13 described above. It is possible to reduce the generation of thermal stress in the welded portion which causes cracking and deformation.

The present invention provides the heat conduction surface as described above, and thus the mainstream gas region in the combustion gas passage is enlarged, and the heat conduction effect is greatly improved by interacting with the leading edge by the slit 13 installed in the fin. .

In addition, the aforementioned slit 13 can prevent the occurrence of thermal stress due to the temperature difference between the flat fin FIN and the water pipe, and can prevent cracking of the fin FlN or the water pipe.

Claims (2)

The upper tube support 1 and the lower tube support 2 together form an annular shape, and the upper and lower pipe supports 1 and 2 are connected by a plurality of water pipes, and these water pipes are radially spaced two Arranged to be concentric inner and outer annular water pipe rows (3) and (4), and annular water pipe heat combustion gas passages by these inner and outer water pipe rows (4) and (3). (5) forms a combustion chamber (7) in the inner annular water pipe row (3) and an open point (9) toward the outer annular combustion gas passage (5) in the inner annular water pipe row (3). The outer surface of the water pipe, which forms an open point 10 connected to the smoke passage 11 formed in the outer wall of the boiler 8, and which faces the combustion gas passage 5. In a multi-tubular perfusion boiler in which multi-stage fins (FIN) 12 are arranged in a multi-stage direction toward the viewing direction, the flat fins 12 are placed in the middle of the smoke passage. In the case of the horizontal plane including the extension line L, the downstream fin end along the flow direction of the combustion gas is arranged to be farther than the upstream fin end, so that the heat conduction plane of the multi-tubular perfusion boiler is arranged. . 2. The structure of the heat conduction surface of a multi-tubular perfusion boiler according to claim 1, wherein the flat fin (FIN) is configured such that an appropriate number of slits (13) are provided so as to substantially cross with respect to the flow direction of the combustion gas. .