US20240142182A1

US20240142182A1 - Heat transfer fin of fin-tube type heat exchanger

Info

Publication number: US20240142182A1
Application number: US18/498,639
Authority: US
Inventors: Seung Jun CHOI; In Chul Jeong; Jun Gil PARK
Original assignee: Kyungdong Navien Co Ltd
Current assignee: Kyungdong Navien Co Ltd
Priority date: 2022-11-01
Filing date: 2023-10-31
Publication date: 2024-05-02
Also published as: CN117989914A; GB202316720D0

Abstract

A heat transfer fin according to an aspect of the present invention includes a fin main body having a plate shape, and a plurality of through-holes defined to pass through the fin main body and spaced apart from each other in a first direction that is a predetermined direction.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of Korean Patent Application No. 10-2022-0143969 filed on Nov. 1, 2022, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a heat transfer fin used in a fin-tube type heat exchanger.

Description of the Related Art

In general, a burner including a heat source for dissipating heat, and a heat exchanger which transfers, to a heat medium, radiant heat dissipated from the heat source and convection heat of a combustion gas generated from the burner and heats heating water, are disposed in apparatuses such as boilers, water heating apparatuses, and hot water pads.
A tube is disposed in the heat exchanger, the heat medium flows along the inside of the tube, and the combustion gas flows outside the tube. Thus, heat exchange between the heat medium and the combustion gas is indirectly performed through the tube.
A plurality of fins may be fitted into the tube so that the heat exchange is easily performed through the tube. This kind of heat exchanger is termed a fin-tube type heat exchanger. As plate-shaped fins are fitted into the tube, a surface area in contact with the combustion gas may increase, and a larger amount of heat may be transferred to the heat medium from the combustion gas.
However, as the heat is excessively concentrated on a partial region of the tube, the fin-tube type heat exchanger is prone to lime formed as calcium ions or the like of the heating water, which are mainly used as the heat medium flowing inside the tube, are precipitated as oxides. Accordingly, there are limitations that this lime blocks the flow of the heating water to reduce an amount of heat transferred by the combustion gas and also reduce a flow rate of the heating water passing through the tube.

SUMMARY OF THE INVENTION

The present invention has been devised to solve the limitations as above, and an aspect of the present invention provides a heat transfer fin used in a fin-tube type heat exchanger with improved temperature distribution characteristics.
According to an aspect of the present invention, there is provided a heat transfer fin including a fin main body having a plate shape, and a plurality of through-holes defined to pass through the fin main body and spaced apart from each other in a first direction that is a predetermined direction. When a direction, which perpendicularly crosses the first direction and in which a combustion gas flows along a surface of the fin main body, is referred to as a second direction, the fin main body includes an end circumferential part surrounding a first end region that is a region, which is disposed at the uppermost upstream side on the basis of the second direction, of regions on the through-hole, and an intermediate circumferential part extending from the end circumferential part in the second direction and surrounding an intermediate region that is a region, which is disposed at a downstream side of the first end region on the basis of the second direction, of the regions on the through-hole. A width of the intermediate circumferential part in the first direction gradually increases in the second direction.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a front view of a heat transfer fin according to an embodiment of the present invention; and

FIG. 2 is an enlarged front view illustrating an area A in FIG. 1 .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, some embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that like components in the drawings are designated by like reference numerals as far as possible even if they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted to avoid making the subject matter of the present invention unclear.
The terms such as “first”, “second”, “A”, “B”, “(a)”, and “(b)”, may be used to describe elements according to an embodiment of the present invention. However, since the terms are used only to distinguish an element from another, the essence, sequence, and order of the elements are not limited by them. When it is described that an element is “coupled to”, “engaged with”, or “connected to” another element, it should be understood that the element may be directly coupled or connected to the other element but still another element may be “coupled to”, “engaged with”, or “connected to” the other element between them.
FIG. 1 is a front view of a heat transfer fin 1 according to an embodiment of the present invention. FIG. 2 is an enlarged front view illustrating an area A of the heat transfer fin 1 according to an embodiment of the present invention.
Referring to the drawings, the heat transfer fin 1 according to an embodiment of the present invention includes a fin main body 10 and through-holes 20 defined in the fin main body 10. In the drawings, a direction indicated by an arrow pointing horizontally opposite directions is a first direction D1 that is a direction in which the through-holes 20 are disposed to be spaced apart from each other. In the drawings, a direction indicated by an arrow pointing a direct vertically downward direction is a second direction D2 that is a direction in which a combustion gas flows inside a heat exchanger in which the heat transfer fin 1 is used. A tube (not shown) coupled to each of the heat transfer fins 1 may extend in a third direction D3 perpendicularly crossing the first direction D1 and the second direction D2. The heat transfer fins 1 may be provided in plurality, and disposed to be spaced apart from each other in the third direction D3 in which the tube extends. The plurality of heat transfer fins 1 coupled to one tube may be disposed to be spaced apart from each other in the third direction D3, and a plurality of tubes coupled to one heat transfer fin may be disposed to be spaced apart from each other in the first direction D1.
Fin Main Body (10)
The fin main body 10 is a plate-shaped component that transfers heat to the tube. The fin main body 10 may have a plate shape perpendicular to the third direction D3. The plurality of through-holes 20 are disposed to be spaced apart from each other in the first direction D1 while passing through the fin main body 10, and a through-region 15 having a shape, which is recessed in the second direction D2 from an end disposed at an upstream side of the fin main body 10 on the basis of the second direction D2, is defined.
The fin main body 10 may be made of a metallic material that has high thermal conductivity and is variously shapable. The tube may be inserted into the through-hole 20 defined in the fin main body 10 so that the tube and the fin main body 10 are coupled to each other, and the fin main body 10 transfers the received heat to the tube. In order not to use a separate coupling hole that connects the fin main body 10 to the tube, an area of the through-hole 20 when viewed in the third direction D3 may be slightly less than a cross-sectional area of the tube taken along a plane perpendicularly crossing the third direction D3 so that the tube is press-fitted and coupled to the through-hole 20. Alternatively, the tube and the fin main body 10 may all be made of a metal and coupled to each other by welding, brazing, soldering or the like. However, the coupling method of the tube and the fin main body 10 is not limited thereto.
The through-hole 20 and the through-region 15 are defined in the fin main body 10. Each of the through-hole 20 and the through-region 15 may be provided in plurality. Thus, an interstitial region 11 may be provided between adjacent through-holes 20 and at a downstream side of the through-region 15 on the basis of the second direction D2. A louver part 14 may be provided in the interstitial region 11. In addition, a partial region of the fin main body 10 may be a circumferential part to be described later.
Through-Hole (20)
The through-hole 20 is a hole that is defined to pass through the fin main body 10 so that the tube through which a heat medium flows is insertable along an inner hollow of the through-hole 20. As the tube passes through the inner hollow of the through-hole 20, the through-hole 20 is defined as an opening that is opened in the third direction that is the direction in which the tube extends. In the drawings, the third direction is an inserting and withdrawing direction.
The through-hole 20 may have a shape of a long hole extending in the second direction D2. As the through-hole 20 has this long hole shape, both end regions 21 and 22 are defined in the through-hole 20, and an intermediate region 23 is defined between both the end regions 21 and 22. A profile of the through-hole 20 in the fin main body may be provided so that a plurality of curved lines such as arcs or parabolas are continuously coupled to each other. In addition, a flat tube having a cross section that is elongated in one direction may be inserted into this through-hole 20. The cross section of the flat tube may have a shape of a long hole in which a length in the second direction is greater than a width in the first direction, like the shape of the through-hole 20.
Each of the tubes has a heat transfer area through which the tube is in contact with the combustion gas to receive the heat. When the flat tube has the same cross section as a circular tube or an oval tube, the heat transfer area of the flat tube may be greater than a heat transfer area of the circular tube or oval tube so that the flat tube has better thermal efficiency than the circular tube or the oval tube.
A boiling point of heating water flowing through the inside of the flat tube may be similar to a boiling point of heating water flowing through the inside of the circular tube or oval tube. However, due to the shape of the cross section, the flat tube is more prone to the generation of lime inside the tube, compared to when lime is generated inside the circular tube or oval tube. A region, which is first in contact with the combustion gas, of an end of the flat tube that is checkable in a direction which the cross section of the flat tube extends may be overheated so that the boiling easily occurs and lime is easily generated. The heat transfer fin 1 according to an embodiment of the present invention may be used in this flat tube to prevent the overheating so that the occurrence of boiling and the generation of lime are reduced.
A first end region 21 and a second end region 22 of the through-hole 20 are defined at the uppermost upstream side and the lowermost downstream side of the intermediate region 23 of the through-hole 20, respectively, on the basis of the second direction D2. Thus, the intermediate region 23 is a region that is disposed at the downstream side of the first end region 21 and disposed at the upstream side of the second end region 22, and thus is adjacent to each of the first end region 21 and the second end region 22.
When the through-hole 20 is constituted by the plurality of arcs, the intermediate region 23 may be constituted by two arcs, which are axisymmetric about a central line parallel to the second direction D2, the first end region 21 and the second end region 22 may be constituted by two arcs, which are axisymmetric about a central line parallel to the first direction D1, and the arranged arcs may be continuously connected to each other to provide the through-hole 20. In this case, a curvature radius of a profile of the first end region 21 may be less than a curvature radius of each of the arcs constituting the intermediate region 23. Thus, a change in curvature occurs at an inner contact point that is a point at which two different arcs meet each other.
The through-hole 20 may be provided in plurality, and the plurality of through-holes 20 may be disposed to be spaced apart from each other in the first direction D1. The through-holes 20 may be disposed at predetermined intervals in the first direction D1. Although FIG. 1 illustrates four through-holes 20 in total, the number of the through-holes 20 is not limited thereto.
Circumferential Part
Referring to the drawings, the fin main body 10 included in the heat transfer fin 1 according to an embodiment of the present invention includes an end circumferential part 12 surrounding a partial region of the through-hole 20. The fin main body 10 may include a circumferential part. The circumferential part is a concept including an intermediate circumferential part 13 and the end circumferential part 12.
At least both sides of the intermediate region 23 of the through-hole 20 in the first direction are surrounded by the intermediate circumferential part 13, and an edge of the first end region 21 of the through-hole 20 is surrounded by the end circumferential part 12. The intermediate circumferential part 13 is provided to extend from the end circumferential part 12 in the second direction D2. Thus, the circumferential part surrounds at least a partial region of the through-hole 20.
The circumferential part may be provided in plurality so that a plurality of circumferential parts are disposed in the plurality of through-holes 20, respectively, and shapes of the circumferential parts may be different from each other.
The intermediate circumferential part 13 is a partial region of the fin main body 10, which surrounds the intermediate region 23 of the through-hole 20. The intermediate circumferential part 13 may have a shape protruding outward from the edge of the intermediate region 23. In addition, the intermediate circumferential part 13 may have a shape that extends in a direction inclined in the second direction D2 to the outside on the basis of the first direction D1 when viewed in the third direction D3. A profile of an outer boundary 131 of the intermediate circumferential part 13 may be the same as a profile of the intermediate region 23 of the through-hole 20.
An inner boundary 132 of the intermediate circumferential part 13 is a boundary that distinguishes the intermediate circumferential part 13 from the intermediate region 23. The outer boundary 131 of the intermediate circumferential part 13 is a boundary that distinguishes the intermediate circumferential part 13 from the outside of the fin main body 10.
The inner boundary 132 of the intermediate circumferential part 13 may have a parabolic shape that is convex to the outside on the basis of the first direction D1. The outer boundary 131 of the intermediate circumferential part 13 may have a linear shape that is inclined in the second direction D2 to the outside on the basis of the first direction D1.
A width of the intermediate circumferential part 13, which is a distance between the inner boundary 132 of the intermediate circumferential part 13 and the outer boundary 131 of the intermediate circumferential part 13 on the basis of the first direction D1, gradually increases in the second direction D2. The minimum distance from one point of the inner boundary 132 of the intermediate circumferential part 13 to the outer boundary 131 of the intermediate circumferential part 13 may gradually increase in the second direction D2. W3 that is a width obtainable at the uppermost upstream side of the intermediate circumferential part 13 is less than W4 that is a width obtainable at a downstream side of the intermediate circumferential part 13. As the thickness of the intermediate circumferential part 13 gradually increases in the second direction D2, heat may be better transferred to the tube at the downstream side of the intermediate circumferential part 13 on the basis of the second direction D2, when compared to the upstream side of the intermediate circumferential part 13. Accordingly, the heat concentrated on the upstream side of the tube may be better dispersed.
The end circumferential part 12 is a partial region of the fin main body 10, which surrounds the first end region 21 of the through-hole 20, and may have a shape protruding outward from an edge of the first end region 21 of the through-hole 20 similarly to the intermediate circumferential part 13. In addition, the end circumferential part 12 may have a profile having a shape that is convex upward when viewed in the third direction.
The end circumferential part 12 may be provided to be continuous from the intermediate circumferential part 12. Thus, each of an outer contact point P1 and an inner contact point P2 that are connection points may be provided in two on a surface on which the end circumferential part 12 and the intermediate circumferential part 13 are in contact with each other. A distance from the outer contact point P1 to the inner contact point P2 may be the same as W3 that is the width of a portion at the uppermost upstream side of the intermediate circumferential part 13.
When a circular tube or an oval tube is used in a heat exchanger, heat may be prevented from being concentrated on an upstream side of the tube by defining a groove in a region corresponding to an end circumferential part or cutting a region disposed at an upstream side of a circumferential part in order to prevent lime or boiling noise from occurring in the tube.
However, a flat tube has a large heat exchange area at an upstream side of the flat tube, and thus it may be difficult to reduce an amount of the lime formed in the flat tube only by defining several grooves in a circumferential part disposed around the flat tube or cutting a portion at the uppermost upstream side of the circumferential part. This is because remaining portions except the recessed grooves or the cut portions are disposed around the tube as they are, and thus the heat of the combustion gas may be still concentrated through the remaining portions and transferred to the tube.
Thus, the end circumferential part 12 according to an embodiment of the present invention may be provided so that W2 or W1 that is the minimum distance between the inner boundary 122 and the outer boundary 121, which is obtained in a region other than a region at the lowermost downstream side of the end circumferential part 12 on the basis of the second direction D2, is less than W3 that is the minimum distance between the inner boundary 122 and the outer boundary 121, which is obtained at the lowermost downstream side of the end circumferential part 12. As above, the end circumferential part 12 may have a shape in which an area as a whole is reduced, so that even when the flat tube is used in the heat exchanger, the heat is made less concentrated on the end circumferential part 12 to prevent the heat transfer fin 1 from overheating, to reduce the amount of lime generated in the tube, and to reduce the boiling noise.
As the intermediate region 23 and the first end region 21 of the through-hole 20 are distinguished from each other at the inner contact point P2 that is a connection point, a definition of a curved line constituting the profile of the through-hole 20 may also be changed. In addition, as the outer boundary 121 of the end circumferential part meets the outer boundary 131 of the intermediate circumferential part at the outer contact point P1 that is a connection point, the outer boundary 121 of the end circumferential part and the outer boundary 131 of the intermediate circumferential part may be represented as curved lines that are defined to be different from each other at the outer contact point P1. A straight line that connects the inner contact point P2 to the outer contact point P1 may be parallel to the first direction D1.
The through-region 15 having a shape in which the fin main body 10 is recessed is defined between two end circumferential parts 12 that surround first end regions 21 of two through-holes 20 adjacent to each other in the first direction D1, respectively. The through-region 15 is opened to pass from the inside of the fin main body 10 in a direction opposite to the second direction D2. As the through-region 15 is defined, the end circumferential part 12 and the intermediate circumferential part 13 may be naturally exposed to the outside of the fin main body 10. That is, the through-region 15 is disposed between the adjacent circumferential parts, and the fin main body 10 has a corrugated profile due to the through-region 15 and the circumferential parts.
The through-region 15 may have a shape having a width that gradually increases from a semicircle recessed in the second direction D2 toward the direction opposite to the second direction D2. A shape of an upstream side of the through-region 15 is determined according to the shape of the end circumferential part 12.
The end circumferential part 12 may be defined as a region that is defined between the inner boundary 122 and the outer boundary 121. The inner boundary 122 of the end circumferential part 12 is a boundary that distinguishes the end circumferential part 12 from the first end region 21 of the through-hole 20, and the outer boundary 121 of the end circumferential part 12 is a boundary that distinguishes the end circumferential part 12 from the outside of the fin main body 10. A region, which is defined by the inner boundary 122, the outer boundary 121, and a boundary between the intermediate circumferential part 13 and the end circumferential part 12, is the end circumferential part 12.
A virtual curved line corresponding to an outer boundary of an end circumferential part of an existing heat transfer fin may be referred to as a reference curved line. The reference curved line may be provided as a curved line having a shape corresponding to the inner boundary 122. The reference curved line passes a specific point while maintaining a constant distance with the inner boundary 122 on the same plane as the inner boundary 122. The phrase “maintaining a constant distance between the inner boundary 122 and the reference curved line” means that the minimum distance from one point on the inner boundary 122 to the reference curved line is the constant distance and is the same at every point. This specific point is an intersection at which the outer boundary 121 crosses a reference straight line L1 that is a virtual straight line drawn to be parallel to the first direction D1. The phrase “the same plane as the inner boundary 122” means a plane including a wider surface of the fin main body illustrated in the drawings. This is because that the inner boundary 122 has a profile having curved line on the plane including the wider surface of the fin main body, which is parallel to each of the first direction D1 and the second direction D2.
When the minimum distance from one point on the inner boundary 122 to the reference curved line is defined as a width of the existing end circumferential part, the width is uniformly maintained with respect to the entirety of the existing end circumferential part. The width of the existing end circumferential part may be the same as the width of a portion at the uppermost upstream side of the intermediate circumferential part 13, and thus may be the same as W1.
The outer boundary 121 of at least one end circumferential part 12 according to an embodiment of the present invention may be disposed inside the reference curved line. Here, the phrase “the outer boundary 121 being disposed inside the reference curved line” means that the outer boundary 121 is disposed at the downstream side in the second direction D2 from reference curved line.
W1, which is the minimum distance to the first end region 21 of the through-hole 20, which is obtained in a region, which is disposed at the uppermost upstream side on the basis of the second direction D2, of regions on the end circumferential part 12, is less than W3 which is a distance between the inner contact point P2 of one side, at which the end circumferential part 12 meets the intermediate circumferential part 13, and the outer contact point P1 of the same side. Thus, the uniform width may not be maintained with respect to the end circumferential part 12, and the width of the end circumferential part 12 may have a tendency to gradually decrease toward the upstream side.
The minimum distance from a point on the inner boundary 122 of the end circumferential part 12 to the outer boundary 121 may be defined as the width of the end circumferential part 12. The width of the end circumferential part 12 may gradually decrease as the point moves along the inner boundary 122 in the direction opposite to the second direction D2. According to this tendency, W2 that is the minimum distance to the outer boundary 121 from one point on the inner boundary 122, which is disposed in the middle of the end circumferential part 12, is less than W3 and greater than W1. In this case, W1, which is the width of the end circumferential part 12 in the region disposed at the uppermost upstream side of the end circumferential part 12, is the minimum value of the entire width of the end circumferential part 12.
In addition, points, at which the lengths of each of the outer boundary 121 and the inner boundary 122 is divided into N portions (here, N is a natural number that is a predetermined number), may be connected to each other to provide the outer boundary 121 and the inner boundary 122, respectively. The minimum distance, which is obtained by connecting a n-th point (here, n is a natural number less than or equal to N) of these divided points of the inner boundary 122 to a n-th point of the outer boundary 121, may gradually decrease as n approaches (N+1)/2.
When each of the outer boundary 121 and the inner boundary 122 of the end circumferential part 12 is provided as an arc, a curvature radius of the outer boundary 121 may be greater than a curvature radius of the inner boundary 122.
The width of the end circumferential part 12 may gradually decrease linearly toward the upstream side on the basis of the second direction D2. Here, the expression “decreasing linearly” is used as a meaning of having a linear proportional relationship between a degree of movement to the upstream side on the basis of the second direction D2 and a degree of a decrease in width of the end circumferential part 12 when moving to the upstream side by the amount of movement.
Due to the shape of the circumferential part described above, concentration of the heat on the upstream side of the tube, which is disposed in the first end region 21 of the through-hole 20, is reduced. Accordingly, the temperature in the tube may be relatively decreased to reduce precipitation of lime that is a calcium oxide. In addition, in the structure of the heat transfer fin 1 according to an embodiment of the present invention, the area may not be simply reduced, but the width of each of the end circumferential part 12 and the intermediate circumferential part 13 may be provided to gradually decrease toward the first end region 21 of the through-hole 20 so that the amount of the transferred heat is prevented from being rapidly reduced to deteriorate heating efficiency.
Main Body Outer Part (30)
Referring to the drawings, a main body outer part 30 may be provided to protrude outward from at least a partial region at each of both ends of the fin main body 10 according to an embodiment of the present invention in the first direction D1. As the main body outer part 30 is disposed at each of both the ends of the fin main body 10 on the basis of the first direction D1, two main body outer parts 30 may be disposed to be axisymmetric about the central line parallel to the second direction D2.
In an embodiment of the present invention, the main body outer part 30 protrudes from a partial region, which is disposed at a downstream side on the basis of the second direction D2, of a region of at each of both the ends of the fin main body 10 in the first direction D1. However, the position from which the main body outer part 30 protrudes is not limited thereto.
A side louver 34 may be defined in the main body outer part 30. The side louver 34 means an opening that passes through the main body outer part 30 in a direction parallel to the third direction and extends in one direction inclined with respect to the second direction D2 on a plane perpendicular to the third direction. As illustrated, the one direction may be a direction that is gradually close to the fin main body 10 in the second direction D2.
A punch tool that presses a metal plate and defines a through-hole may be used to provide the side louver 34. When the through-hole is defined using this pressing member, a pressed material may protrude from a boundary of the through-hole in the pressing direction so that a side burr is formed. The side burr protrudes and serves to guide the combustion gas to flow to the tube fitted into the through-hole 20 adjacent to the side louver 34.
The side louver 34 may be provided in plurality. In an embodiment of the present invention, the side louver 34 includes a first side louver 341, and a second side louver 342 disposed to be spaced apart from first side louver 341 in the second direction D2. These plurality of side louvers 34 may have different lengths.
The first side louver 341 may extend toward a protrusion 32, which is provided to more protrude from a body 31 of the main body outer part 30 in the direction opposite to the second direction D2, so that a portion of the first side louver 341 is disposed in the protrusion 32. The protrusion 32 may be provided to more protrude outward from a partial region adjacent to an upstream side of the main body outer part 30.
The second side louver 342 may be provided in plurality, and a plurality of second side louvers 342 may extend in the first direction D1 and be spaced apart from each other in the second direction D2. One of the second side louvers 342, which is disposed at the relatively upstream side, may have a greater width in the first direction D1 than another disposed at the relatively downstream side.
The second side louver 342 may be defined in the body 31 of the main body outer part 30. The body 31 of the main body outer part 30 may have a shape, in which a width in the first direction D1 gradually decreases in the second direction D2, and thus an outer boundary thereof may have a profile inclined inward in the second direction D2. Thus, the large-small relationship in the width as described above may apply to the second side louver 342. A portion of the second side louver 342 may be disposed in the body 31 of the main body outer part 30.
The heat transfer fin 1 according to an embodiment of the present invention may have the side louver 34 described above so that the combustion gas is more concentrated on and pass through the intermediate region 23 than the end at the upstream side of the through-hole 20, and the heat medium is uniformly heated at various positions.
A fin side groove 33 having a shape of a fin recessed in the second direction D2 may be defined in the upstream side of the main body outer part 30 on the basis of the second direction D2. The fin side groove 33 may be surrounded by the protrusion 32, the body 31 of the main body outer part 30, and the fin main body 10. A groove end that is an end disposed at a downstream side of the fin side groove 33 may have a semicircular profile on a plane perpendicularly crossing the third direction.
As the fin side groove 33 is define as illustrated, the protrusion 32 and the fin main body 10 may be spaced apart from each other. Accordingly, it may be made difficult for the heat transferred to the protrusion 32 by the combustion gas to move to the end circumferential part 12 via the body 31 of the main body outer part 30 and the intermediate circumferential part 13. Accordingly, the heat may be prevented from being concentrated on the first end region 21.
As the fin side groove 33 according to an embodiment of the present invention is defined, there is an effect that a heat transfer area capable of transferring the heat to the tube is reduced. Accordingly, the temperature of the tube may be decreased to reduce precipitation of lime.
Louver Part (14)
Referring to FIG. 1 again, the interstitial region 11 may be defined in a region of the fin main body 10, which is disposed between the through-holes 20 adjacent to each other and at the downstream side of the fin main body 10 that is the downstream side of the through-region 15, and the louver part 14 may be further defined in the interstitial region 11. The louver part 14 may be defined in a region, which is adjacent to the second end region 22 of the through-hole 20, of the interstitial region 11. According to an embodiment of the present invention, the louver part 14 includes a burring hole and a burr.
The burring hole is an opening that is defined to pass through the interstitial region 11 of the fin main body 10 in the third direction by using a punch tool or the like as described with respect to the side louver 34, and the burr is provided to protrude along at least a portion of a circumference of the burring hole in the third direction. Accordingly, the combustion gas blocked by the burr of the louver part 14 during the flow may be allowed to flow to a central area of the through-hole 20, and the heat medium passing through the tube may be heated more uniformly.
A plurality of louver parts 14 may be disposed in one interstitial region 11. The louver parts 14 disposed in one interstitial region 11 may be provided in four as illustrated in FIG. 1 , and the four louver parts 14 may be disposed to be spaced apart from each other in the second direction D2 and have a shape in which a width in the first direction D1 gradually increase toward the downstream side. In addition, the burring hole of one louver part, which is disposed at the relatively downstream side, of two louver parts may have a width that is greater than a width of the burring hole of the other louver part disposed at the relatively upstream side. However, the arrangement and the width of the louver part are not limited thereto.
Accordingly, the temperature distribution characteristics of the heat transfer fin is improved, and the formation of the lime in the tube coupled to the heat transfer fin is reduced.
Although all of the components constituting the embodiments of the present invention are described to be combined as one unit or to operate as a combination thereof, the present invention is not necessarily limited to these embodiments. That is, within the scope of the present invention, all of the components may be selectively combined to one or more thereof to operate as a combination. The term such as “comprising,” “configure”, or “having”, specifies the presence of components, unless there is a clearly different meaning in the present disclosure, but do not preclude the presence thereof and should be construed to further include other components. Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The description of the present invention is intended to be illustrative, and various changes and modifications can be made by those of ordinary skill in the art to which the present invention pertains, without departing from the spirit and scope of the present invention as defined by the appended claims. Therefore, the embodiments set forth herein are to describe the technical spirit of the present invention and not to limit. The scope of the technical spirit of the present invention is not limited by the embodiments. Moreover, the protective scope of the present invention should be determined by reasonable interpretation of the appended claims and all technical concepts coming within the equivalency range of the present application should be interpreted to be in the scope of the right of the present application.

Claims

What is claimed is:

1. A heat transfer fin comprising:

a fin main body having a plate shape; and

a plurality of through-holes defined to pass through the fin main body and spaced apart from each other in a first direction that is a predetermined direction,

wherein, when a direction, which perpendicularly crosses the first direction and in which a combustion gas flows along a surface of the fin main body, is referred to as a second direction, the fin main body comprises:

an end circumferential part configured to surround a first end region that is a region, which is disposed at the uppermost upstream side on the basis of the second direction, of regions on the through-hole; and

an intermediate circumferential part provided to extend from the end circumferential part in the second direction and configured to surround an intermediate region that is a region, which is disposed at a downstream side of the first end region on the basis of the second direction, of the regions on the through-hole,

wherein a width of the intermediate circumferential part in the first direction gradually increases in the second direction.

2. The heat transfer fin of claim 1, wherein an inner boundary of the intermediate circumferential part, which is a boundary that distinguishes the intermediate circumferential part from the intermediate region, has a parabolic shape.

3. The heat transfer fin of claim 1, wherein an outer boundary of the intermediate circumferential part, which is a boundary that distinguishes the intermediate circumferential part from the outside of the fin main body, has a linear shape.

4. The heat transfer fin of claim 1, wherein an inner boundary of the end circumferential part, which is a boundary that distinguishes the end circumferential part from the first end region, and

an outer boundary of the end circumferential part, which is a boundary that distinguishes the end circumferential part from the outside of the fin main body.

5. The heat transfer fin of claim 4, wherein a minimum distance between the inner boundary of the end circumferential part and the outer boundary of the end circumferential part, which is obtained in a region, which is disposed at the uppermost upstream side on the basis of the second direction, of regions on the end circumferential part is less than a minimum distance between the inner boundary of the end circumferential part and the outer boundary of the end circumferential part, which is obtained in another region of the regions of the end circumferential part.

6. The heat transfer fin of claim 4, wherein a minimum distance between the inner boundary of the end circumferential part and the outer boundary of the end circumferential part, which is obtained in a region, which is disposed at the uppermost upstream side on the basis of the second direction, of regions on the end circumferential part is less than a minimum distance between the inner boundary and the outer boundary, which is obtained in a region, which is disposed at the lowermost downstream side on the basis of the second direction, of the regions on the end circumferential part.

7. The heat transfer fin of claim 4, wherein a minimum distance from a point on the inner boundary of the end circumferential part to the outer boundary of the end circumferential part gradually decreases along the inner boundary of the end circumferential part in a direction opposite to the second direction.

8. The heat transfer fin of claim 4, wherein, when the outer boundary of the intermediate circumferential part is a boundary that distinguishes the intermediate circumferential part from the outside of the fin main body, the outer boundary of the end circumferential part and the outer boundary of the intermediate circumferential part, which is connected to the outer boundary, are defined to be different from each other at least at a connection point thereof.

9. The heat transfer fin of claim 1, wherein a through-region, which passes through the fin main body so as to be opened from the inside of the fin main body in the direction opposite to the second direction, is defined between two end circumferential parts that surround first end regions of two through-holes disposed to be adjacent to each other in the first direction, respectively.

10. The heat transfer fin of claim 1, further comprising two main body outer parts, each of which protrudes outward from at least a partial region of each of both ends of the fin main body in the first direction.

11. The heat transfer fin of claim 10, wherein a fin side groove is defined to be recessed in the second direction in an upper end of a main body outer part, which is disposed at an upstream side of the main body outer part on the basis of the second direction.

12. The heat transfer fin of claim 11, wherein a groove end disposed at a downstream side of the fin side groove on the basis of the second direction has a semicircular profile.