Heat exchanger assembly with wrapped tubing.

摘要

A method and apparatus for forming a heat exchanger assembly (20) including wrapping a one-piece heat exchanger tube (22) onto a heat transfer unit (21) having a plurality of fins on upper and lower surfaces, the fins being provided with notches (25, 25a) which are aligned in sets with each set of notches receiving a section of the heat exchanger tube (22) as it is wrapped around the heat transfer array, return bend portions (32, 33) of the heat exchanger tube (22) being formed in the wrapping process to have a generally rectangular cross section to maximize the cross sectional area of the heat exchanger tube (22) in the return bend areas (32,33) of the tube. Apparatus for forming the heat exchanger assembly includes a mandrel (51) for rotating the fin unit (21), drawing the heat exchanger tube (22) around the fin unit (21), and forming devices (60) mounted on the mandrel (51) to define the pitch of the return bends (32,33) and to maintain the cross section of the heat exchanger tube (22) in the return bend portions (32,33) generally rectangular in shape when the heat exchanger tube (21) subsequently is expanded.