Carrier Corporation

Hannu Tapani Heiskanen

Steven J Spencer

Daniel P Gaffaney

Donald L Bennett

Edward G Rottmann

Gerald Lee Riggs

James Marvin Satterly

A heat transfer tube having an internal surface that enhances the heat transfer performance of and also improves the workability of the tube and a method of manufacturing such a tube. The internal surface has a plurality of ribs that extend at an angle to the longitudinal axis of the tube. A pattern of parallel notches, extending at an angle to the ribs, extend through the ribs and into the main inner surface of the tube wall. The tube can be made by rolling embossing the pattern of ribs and notches on to one side of a flat metal strip, then roll forming the strip into a tubular shape with the embossed pattern on the interior of the tubular shape and the edges of the strip forming a longitudinal seam, then joining, preferably by welding, the edges along the longitudinal seam to form a tube. In a preferred embodiment, the notches in the inner surface extend into the weld zone of the tube. The pattern of ribs and notches increase the total internal surface area of the tube and also promote conditions for the flow of refrigerant within the tube that increase heat transfer performance. The notches also serve to inhibit the propagation of splits in the tube wall when the tube is flared.

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Bowling Green, KY, United States of America

Hannu Tapani Heiskanen