Method of manufacturing heat exchanger pipe

A method of manufacturing a heat exchanger pipe, the method comprising:

• an insert preparation process of placing a contact shell on an upper bed;
• an outer pipe preparation process of placing the outer pipe on a lower bed to insert the contact shell into the outer pipe;
• a pressing-preparation process of disposing a dice mold having a tapered portion and a pressing portion over the outer pipe;
• and
• a pressing process of pressing the outer pipe with the pressing portion so that the inner circumferential surface of the outer pipe comes in direct surface-to-surface contact with the outer circumferential surface of the contact shell,
• wherein a plurality of heat exchanger fins are protrudingly formed on the inner circumferential surface of the contact shell,
• wherein the heat exchanger fins comprise at least one first fin group and at least one second fin group,
• wherein the first fin group comprises a plurality of first heat exchanger fins, which are discontinuous type heat exchanger fins that are disconnected at middle portions in a longitudinal direction thereof and consecutively positioned,
• wherein the second fin group comprises a plurality of second heat exchanger fins, which are continuous type heat exchanger fins that are entirely continuous in a longitudinal direction thereof and consecutively positioned,
• wherein the first fin group and the second fin group are alternately disposed, and
• wherein the second fin group is composed of three continuous type heat exchanger fins disposed continuously.