Heat transfer fin of fin-tube type heat exchanger

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.

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.