Spencer & Frank
Method of manufacturing fin-tube heat exchangers
 A method of manufacturing a fin-tube heat exchanger which includes a multiplicity of plate fins arranged in a plurality of rows disposed at a predetermined pitch in the direction of air flow, and a jointless refrigerant pipe extending through the plate fins in a zigzag manner. Pipe-receiving holes are formed in each plate fin in an offset manner relative to the center of the plate fin. The plate fins are then placed in fin-receiving grooves formed in a straight fin positioning fixture at predetermined spacings such that the same longitudinal ends of the plate fins of alternating rows appear on the same side of the fin positioning fixture and such that the pipe-receiving holes are linearly aligned. The refrigerant pipe is inserted into the pipe-receiving holes and is expanded to make tight and close contact with the plate fins. The refrigerant pipe is bent in a zigzag manner so that the straight portiions of the pipe occupy corners of rectangles and so that a predetermined spacing is provided between the plate fins of adjacent rows. Finally, a twist is imparted to the refrigernat pipe to line up the plate fins and arrange the pipe such that the straight portions of the pipe are positioned in a staggered manner, as viewed in the direction of the rows. 
Matsushita Refrigeration Company
B Y F Y F B F
B21D Y10T F25B Y10T F28F B23P F28D
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Yukichi Hironori Satoshi Hachiro Hiroshi Shigeo
Aoki Ito Tanno Koma Yoneda Aoyama