Abstract: A method for folding a metal strip is proposed, the method comprising the steps of providing a metal strip having a first surface and a second surface; providing the metal strip with a groove in the first surface; folding the metal strip into a corner wherein the first surface forms a concave side of the corner and the second surface forms a convex side of the corner and the groove extends along the concave side of the corner; the metal strip being folded by means of at least one set of rollers. According to an important aspect of the invention, one of the rollers comprises a bead pressing the groove into said metal strip, the bead having a substantially rounded profile. The invention further concerns a folded tube having a groove with substantially rounded profile and a forming tool having a bead with substantially rounded profile.

Abstract: A fluid pipe (14) for fluid flow between a pair of manifolds of a heat exchanger and which is formed from a single piece of sheet metallic material having a cladding on at least one surface, the fluid pipe having a first side wall (40) having a first portion (46) and a second portion (48); a second side wall (42) extending substantially parallel to and spaced from the first side wall; a pair of end walls (44) connecting the first and second side walls; first, second and third internal walls (50-54) positioned internally of the first and second side walls and the end walls, the first, second and third internal walls being spaced apart and spaced from the end walls, and extending between the first and second side walls, the first internal wall being of double the thickness of the sheet and being positioned intermediate the second and third internal walls; a first planar side portion (56) connecting the first and second internal walls and contacting a first planar part (58) of the internal surface of the second

Abstract: A fluid pipe (14) for fluid flow between a pair of manifolds of a heat exchanger and which is formed from a single piece of sheet metallic material having a cladding on at least one surface, the fluid pipe having a first side wall (40) having a first portion (46) and a second portion (48); a second side wall (42) extending substantially parallel to and spaced from the first side wall; a pair of end walls (44) connecting the first and second side walls; first, second and third internal walls (50-54) positioned internally of the first and second side walls and the end walls, the first, second and third internal walls being spaced apart and spaced from the end walls, and extending between the first and second side walls, the first internal wall being of double the thickness of the sheet and being positioned intermediate the second and third internal walls; a first planar side portion (56) connecting the first and second internal walls and contacting a first planar part (58) of the internal surface of the second