Heat transfer fin and heat exchanger using thereof

A heat transfer fin made of stainless steel-based metal capable of use in a heat exchanger, wherein

• the heat exchanger has a heat exchanger body in which combustion exhaust gas flows from an upper opening toward a lower opening, and a plurality of heat transfer fins disposed between two opposed side walls of the heat exchanger body, wherein
• the plurality of heat transfer fins are arranged in parallel with a predetermined clearance therebetween;
• the heat transfer fin comprising:
• a plurality of upper stage heat-transfer-tube insertion holes each of which has a substantially elliptical shape elongated in a vertical direction, formed in an upper stage;
• a plurality of lower stage heat-transfer-tube insertion holes each of which has a substantially elliptical shape elongated in the vertical direction, formed in a lower stage;
• upper end cut portions formed between adjacent ones of the plurality of upper stage heat-transfer-tube insertion holes;
• lower end cut portions formed between adjacent ones of the plurality of lower stage heat-transfer-tube insertion holes;
• upper stage support flanges formed along circumferential edges of the plurality of upper stage heat-transfer-tube insertion holes;
• lower stage support flanges formed along circumferential edges of the plurality of lower stage heat-transfer-tube insertion holes;
• burring holes formed below the plurality of upper stage heat-transfer-tube insertion holes;
• and
• standing flanges formed along circumferential edges of the burring holes, wherein
• centers of the plurality of upper stage heat-transfer-tube insertion holes and the plurality of lower stage heat-transfer-tube insertion holes are displaced from one another in a transverse direction,
• the upper end cut portions are formed so as to extend from a fin upper end portion beyond lower ends of the plurality of upper stage heat-transfer-tube insertion holes to positions adjacent to upper ends of the plurality of lower stage heat-transfer-tube insertion holes in the vertical direction,
• the lower end cut portions are formed so as to extend from a fin lower end portion to positions above lower ends of the plurality of lower stage heat-transfer-tube insertion holes in the vertical direction,
• a width of each of the lower end cut portions in the transverse direction increases downward,
• the burring holes are substantially circular holes,
• the lower end cut portions have a substantially semicircular shape,
• the plurality of upper stage heat-transfer-tube insertion holes, the burring holes, and the lower end cut portions are disposed in the transverse direction in such a manner that a center of each of the burring holes and a center of each of the lower end cut portions are in alignment with a vertical center line of each of the plurality of upper stage heat-transfer-tube insertion holes located thereabove,
• the burring holes are disposed in the vertical direction in such a manner that an upper end of each of the burring holes is located above a lower edge of each of the upper end cut portions and a lower end of each of the burring holes is located below the upper end of each of the plurality of lower stage heat-transfer-tube insertion holes, and
• an outside diameter of each of the standing flanges is smaller than an outside diameter of each of the upper stage support flanges located thereabove and is equivalent to a minimum distance between adjacent ones of the plurality of lower stage heat-transfer-tube insertion holes.