Abstract: A heat exchanger having different types of fins of different widths arranged such that different types of fins are arranged alternately can be efficiently produced by a process which has the steps of: forming a plurality of rows of refrigerant-tube holes in a hoop; forming lines of cutting which extend parallel to a direction of feed of the hoop at positions which are offset from the midpoint between adjacent rows of the holes, the lines of cutting having a length smaller than the longitudinal size of fins to be obtained; forming slits or elongated holes in positions of the hoop to which the ends of the lines of cutting is to be extended, the slits or elongated holes having longitudinal axes extending in the direction crossing the direction of feed of the hoop; cutting the hoop along a transverse line of cutting which extends in the direction crossing the direction of feed of the hoop past regions between adjacent slits or elongated holes which oppose to each other in the direction of feed of the hoop, thus s

Abstract: An apparatus for producing various heat exchangers is disclosed in which a plurality of heat exchangers disposed side by side are formed at once. A series of manufacturing stations for working heat exchanger components such as fins and tubes and for opening the tubes are arranged in an endless manner to thereby automatically carry out the production steps with a high productivity while meeting various requirements of the specifications of the heat exchangers with a high flexibility.

Abstract: Disclosed is a tube-enlarging press in which clamping units are provided for preventing the fins and tubes used in a heat exchanger, from being buckled. The clamping units are provided with a through-hole for permitting the passage therethrough of mandrels falling outside of the area of the fin when the mandrels are lowered during the tube enlarging process. Therefore, the arrangements and preparations for replacement of the mandrels can be omitted.

Abstract: A fin-and-tube type heat exchanger is disclosed in which the height of each raised, slotted louver from a fin base portion continuously changes in a direction crossing at right angles both the direction of the air flow and the direction of lamination of fins, and two or three kinds of such louver pairs, each consisting of louvers symmetric with each other with respect to the fin base portion, are arranged regularly.