| 摘要 |
The present invention is provided with a plurality of fins (10) which are disposed with an interval therebetween, and which have a gas flowing therebetween; and a plurality of heat transfer pipes (20) which are inserted into the plurality of fins (10), and which are joined to the plurality of fins (10) by way of pipe expansion. The present invention is characterized in that: the plurality of heat transfer pipes (20) are arranged in at least 5 rows in a row direction along a flow direction of the gas, and are zigzaggedly arranged so as to be staggered alternately in a column direction intersecting the flow direction of the gas; the plurality of fins (10) are formed so as to have a flat-plate shape, and successively join together the space between the plurality of heat transfer pipes (20) in the row direction; and, in cases when D represents the external diameter prior to pipe expansion, Da represents the external diameter after pipe expansion, and L represents the distance between centres of neighbouring heat transfer pipes (20), the plurality of heat transfer pipes (20) satisfy the relationships 1.055D ≤ Da ≤ 1.068D and 1.56Da ≤ L ≤ 2.58Da. |
