ABSORPTION TYPE REFRIGERATING MACHINE AND HEAT EXCHANGER TUBE USED THEREFOR

摘要

PROBLEM TO BE SOLVED: To achieve a higher heat exchange performance by increasing area contributing to heat exchange while preventing excessive retention of a refrigerant liquid and an absorbing liquid with a large surface tension on the external surface of the tube. SOLUTION: A plurality of protruded stripes 2 are arranged spiral side by side almost at an equal interval on the internal surface of a heat exchanger tube 1 made of copper. The protruded stripes 2 are formed at a lead angle of 40-50 deg. and 0.1-0.3 mm high. Protrusion trains 4 comprising a number of protrusions 3 arrayed at a pitch of 0.4-0.8 mm are arranged spiral on the external surface of the tube. The protrusion trains 4 and the protruded stripes 2 are opposite in the spiral pattern, and the protrusions 3 formed in a shape similar to a lower side as obtained when an upper part of a pyramid having a top right above the bottom surface thereof is cut on a plane parallel with the bottom surface. One side of the base part thereof is 0.4-0.7 mm and one side of the top part 3A is 0.2-0.4 mm. The height of the protrusions 2 is 0.2-0.4 mm but the protruded stripes 2 are made lower at a part than at other parts thereof. In any of the protrusion trains 4, the protrusions 3 are arranged in rows at the same pitch but the protrusions 3 in the adjacent protrusion trains 4 are shifted by one third in phase from each other.