Abstract: A double-wall-tube heat exchanger has outer and inner tubes. A clearance between the outer and inner tubes and the interior of the inner tube serve as refrigerant flow paths. Opposite end portions of the inner tube project from opposite ends of the outer tube. The outer tube includes expanded portions formed near the opposite ends. Contracted portions are formed on the outer tube to be located on the outer sides of the expanded portions, and are brazed to the inner tube. Longitudinally extending ridges project radially inward from the inner circumferential surface of the outer tube at predetermined circumferential intervals. The ridges on the inner circumferential surfaces of the expanded portions and the contracted portions are crushed. The clearances between the inner tube and portions of the contracted portions of the outer tube where the ridges are not formed are filled with a brazing filler metal.

Abstract: An evaporator includes a refrigerant inlet header section, a refrigerant outlet header section, and a refrigerant circulation path connecting the two header sections. A refrigerant inlet-outlet member composed of a first plate, a second plate, and an intermediate plate is joined to the two header sections. The refrigerant inlet-outlet member has an inflow channel whose one end communicates with the refrigerant inlet of the refrigerant inlet header section and whose other end is opened to a rear edge of the refrigerant inlet-outlet member, and an outflow channel whose one end communicates with the refrigerant outlet of the refrigerant outlet header section and whose other end is opened to the rear edge. The first and second plates each have inflow-channel-forming and outflow-channel-forming outward swelled portions. Cutouts and a through hole are formed in the intermediate plate such that the inflow channel and the outflow channel cross each other.

Abstract: An evaporator includes a pair of header tanks spaced from each other in a vertical direction; a plurality of flat heat exchange tubes 45 which are disposed between the two header tanks such that their width direction coincides with a front-rear direction and they are spaced from one another in a left-right direction, opposite ends portions of the flat heat exchange tubes being connected to the corresponding header tanks; and corrugated fins 5 each disposed between adjacent heat exchange tubes 45. Each of left and right portions of front and rear end walls 45a of each heat exchange tube 45 has a straight slope portion 55 which inclines outward in the front-rear direction, toward a center portion of the heat exchange tube 45 with respect to the left-right direction. The angle formed between the slope portion 55 and the left edge or right edge of the corresponding corrugated fin 5 is set to 25 to 40 degrees.

Abstract: A double-wall-tube heat exchanger has outer and inner tubes. A clearance between the outer and inner tubes and the interior of the inner tube serve as refrigerant flow paths. Opposite end portions of the inner tube project from opposite ends of the outer tube. The outer tube includes expanded portions formed near the opposite ends. Contracted portions are formed on the outer tube to be located on the outer sides of the expanded portions, and are brazed to the inner tube. Longitudinally extending ridges project radially inward from the inner circumferential surface of the outer tube at predetermined circumferential intervals. The ridges on the inner circumferential surfaces of the expanded portions and the contracted portions are crushed. The clearances between the inner tube and portions of the contracted portions of the outer tube where the ridges are not formed are filled with a brazing filler metal.

Abstract: Each heat exchange tube of an evaporator is composed of two press-worked rectangular metal plates joined together in a stacked condition. The metal plates of the heat exchange tube are swelled outward whereby at least one refrigerant flow space extending in the vertical direction and having opened upper and lower ends is provided in the heat exchange tube. Insertion portions to be inserted into header sections of header tanks of the evaporator via tube insertion holes are provided on upper and lower end portions of each heat exchange tube at positions corresponding to the refrigerant flow space. A concave portion is formed in each of the insertion portions, excluding opposite ends thereof with respect to the front-rear direction, of the upper and lower end portions of each heat exchange tube, the concave portion being concaved inward with respect to a longitudinal direction of the heat exchange tube.

Abstract: An evaporator includes a refrigerant inlet header section, a refrigerant outlet header section, and a refrigerant circulation path connecting the two header sections. A refrigerant inlet-outlet member composed of a first plate, a second plate, and an intermediate plate is joined to the two header sections. The refrigerant inlet-outlet member has an inflow channel whose one end communicates with the refrigerant inlet of the refrigerant inlet header section and whose other end is opened to a rear edge of the refrigerant inlet-outlet member, and an outflow channel whose one end communicates with the refrigerant outlet of the refrigerant outlet header section and whose other end is opened to the rear edge. The first and second plates each have inflow-channel-forming and outflow-channel-forming outward swelled portions. Cutouts and a through hole are formed in the intermediate plate such that the inflow channel and the outflow channel cross each other.