Heat exchanger and method for manufacturing the heat exchanger

A method for manufacturing heat exchanger tubes disposed between a pair of header pipes and connected to said pair of header pipes at their end portions, the method comprising the steps of:

• pressing one of the end portions of a pipe to form the end portion as a connecting portion to be connected to one of said pair of header pipes;
• inserting a wave-shaped plate into said pipe from the other end portion of said pipe, said wave-shaped plate being shorter than said pipe;
• pressing said pipe at its central portion, other than its end portions where said wave-shaped plate does not exist, in a direction transverse to the direction of said pressing of said one end portion of said pipe, to form said central portion as a shape of a flat tube and hold said wave-shaped plate by the inner surface of the pressed central portion;
• and
• pressing said other end portion of said pipe in the same direction as the direction of said pressing of said one end portion of said pipe to form said other end portion as a connecting portion to be connected to the other of said pair of header pipes.

A method for manufacturing a heat exchanger including a pair of substantially parallel header pipes each having a plurality of connection holes and a plurality of substantially parallel flat tubes each having a plurality of end portions and a plurality of partitions therein to form a plurality of flow paths, said flat tubes being disposed between said pair of header pipes and connected to said pair of header pipes at their end portions by inserting their end portions into said connection holes, the method comprising the steps of:

• cutting away the longitudinal end portions of said partitions provided in each of said flat tubes before said pressing step;
• pressing the end portions of each of said flat tubes in the longitudinal direction of the cross section of the flat tube,
• forming said connection holes as a shape corresponding to the shape of said pressed end portions, and
• inserting said pressed end portions into corresponding connection holes.

A method of manufacturing a heat exchanger tube having a central portion and end portions, the tube being adapted for positioning between a plurality of header pipes in the fabrication of a heat exchanger, said method comprising:

• forming a tube having at least the central portion thereof flattened so that the width is larger than the height;
• inserting a rectifying means within the central portion of the tube;
• and
• transversely pressing the end portions of the tube so that they each define a width which is less than the width of the central portion of the tube, said pressing of said end portions being performed such that one of said end portions is transversely pressed before the rectifying means is inserted into the tube and the other is pressed after said insertion of the rectifying means.

A method of manufacturing a heat exchanger tube for assembly into a heat exchanger, said tube being adapted for connecting between a plurality of header pipes at its end portions, said method comprising:

• forming a flat tube having internal partitions which extend axially through the tube, said tube being formed to have a central portion and a pair of end portions and to define a width which is larger than its height;
• substantially removing the end portions of the partitions;
• and
• forming the end portions of the tube after said removing of said ends of the partitions so that the width of the end portions has a smaller width than the width of the central portion thereof.