Tube for heat exchanger

A tube for a heat exchanger, the tube formed from a single sheet of material, the tube having a cross-section comprising

• two opposed side walls and
• two opposed ends, said opposed ends having curved portions, the outer surface of said ends being substantially mirror symmetrical, one of said ends having a double wall comprising an inner wall and an outer wall, one of said side walls extending to form the outer wall and the other of said side walls extending to form the inner wall, wherein each of the outer wall and the inner wall has a respective extremity, the inner wall offset inwardly proximate a region overlaid by the extremity of the outer wall to accommodate the extremity of the outer wall and to provide spacing between the inner wall and the outer wall, the extremity of the inner wall deviating away from the outer wall and providing spacing between the inner wall and the outer wall proximate the extremity of the inner wall.

A method of forming a tube from a single sheet of material, the tube characterized by a cross-section having a single-walled end, a double-walled end, a first side and a second side, said method comprising:

• forming an inner wall of said double wall, said inner wall extending from said first side via a transition region, said inner wall further extending to an inner-wall extremity region;
• forming an outer wall of said double wall, said outer wall extending from said second side, said outer wall further extending to an outer-wall extremity region;
• wherein said transition region accommodates said outer-wall extremity region and provides spacing between the inner wall and the outer wall proximate said outer-wall extremity region, and wherein said inner-wall extremity region deviates away from said outer wall of said double wall to provide spacing between the inner wall and the outer wall proximate said inner-wall extremity region.

A method of forming a tube for a heat exchanger, the tube characterized by a cross-section having two opposing ends and two opposing sides, one of said ends having a double wall, said method comprising:

• forming an inner wall of said double wall, said inner wall extending in a first direction to a first extremity region, said inner wall extending in a second direction to one of said opposing sides via a transition region offset in said one of said opposing sides;
• forming an outer wall of said double wall, said outer wall extending in said first direction to the other of said opposing sides, said outer wall extending in said second direction to a second extremity region;
• wherein said transition region accommodates said second extremity region and said first extremity region deviates away from said outer wall.

A tube for a heat exchanger, the tube formed from a single sheet of material and having a cross-section comprising:

• two opposed ends, one of said ends having a double wall comprising an inner wall and an outer wall, said inner wall and said outer wall each having a respective extremity;
• a first side wall opposed a second side wall, said first side wall extending to form said outer wall and said second side wall extending to form said inner wall,
• wherein the contour of a region of the inner wall is offset inwardly to accommodate said extremity of said outer wall and to provide spacing between said inner wall and said outer wall proximate said extremity of said outer wall, and said extremity of said inner wall deviates from the contour of said outer wall to provide spacing between said inner wall and said outer wall proximate said extremity of said inner wall.