HEAT TRANSFER TUBE

摘要

PROBLEM TO BE SOLVED: To provide a heat transfer tube which spreads an absorption liquid widely over the outside surface of the heat transfer tube to a satisfactory extent and promotes an agitation action of an absorption liquid film in the downward direction (the right angle direction to the tube axial direction) where the absorption liquid flows down and the tube axial direction as well. SOLUTION: This invention relates to a heat transfer tube 1, which exchanges heat between a fluid inside a tube and a fluid outside the tube. The heat transfer tube 1 has at least one type of a first spiral groove M1 on the outer peripheral surface of the heat transfer tube 1 where the groove has a specified twisted angleθ1 with the tube axis Z and cut deep to such an extent that no projected stripe may be formed on the inner peripheral surface of the tube. A second spiral groove M2 having a specified twisted angleθ2 different from the first spiral groove M1 with the tube axis Z is formed on the outer peripheral surface of the heat transfer tube 1 where the groove of the second spiral groove M2 forms a projected stripe N corresponding to the groove on the inner peripheral surface of the tube.