Abstract: An insertion portion of a tube is inserted into a pipe through a tube-insertion aperture formed in the pipe, and the tube-insertion portion is secured to an inner surface of the pipe. The tube may be formed by coupling a pair of tube-forming members. The tube may be provided with a tube-insertion regulating portion at a side of a longitudinal end portion of the tube for regulating a tube-insertion-length relative to the pipe. The coupled pair of tube-forming members are brazed to each other, and that the tube-insertion portion is brazed to the pipe.

Abstract: A plurality of short pipe body sections can be coupled to one another with a coupling which has cylindrical contact about the inner and/or outer surfaces of the pipes to obtain a pipe having a desired length. The coupling also serves as a partitioning plate to block flow of coolant through pipe.

Abstract: A header pipe for an automobile coolant condenser having a W-shaped profile in longitudinal cross section such that the projecting portions of the profile makes two-point contact with the ends of the corrugated fins.

Abstract: The flat tubular heat exchange body is provided with shoulders on each of its peripheral side walls at a fixed distance from each end. The ends of the bodies is shaped and sized to fit into a slot in a header pipe so that when the shoulders strike the surface of the header pipe, the invention is automatically fixed.

Abstract: A header pipe is formed with a plurality of oblong slots which extend radially through the wall of the pipe and have an outside dimension larger than that of the tubular heat exchanger which is inserted in the slot. The peripherally directed edges on the exterior surface of the pipe surrounding the slots are curved to flare outwardly to form a taper for the insertion of the tubular heat exchanger.