Multi-layer pipe and method for its manufacture

A method for manufacture of a multi-layer pipe (5) by means of a bending roller, characterised in that

• individual material layers (1, 2) to be combined into the multi-layer pipe (5) are placed one upon the other,
• subsequently a first connection (3, 3a and 3b, 3a1, and 3a2, 3b1, and 3b2, 3n1 and 3n2) between the material layers (1, 2) is created by connecting them to each other, preferably approximately alongside a longitudinal edge (4) or transverse edge (4a) of the material layer positioned above (1), or preferably approximately alongside a line parallel to the edge,
• the thus formed multi-layer material is shaped into a pipe (5) by means of the bending roller with a constant friction-tight connection being created between the material layers (1, 2) as a result of the pressure of the rollers from the top and from the bottom, and during shaping, the portions (1c, 1d, 2a, 2b) of the material layers (1, 2), which can still shift freely against other, shifting freely to each other in accordance with the shaping progress due to the different bending radii of the one layer (1) acting as an internal pipe and the other layer (2) acting as an external pipe,
• after a predetermined shaping progress at least one other connection (6a, 6b) is created between the material layers (1, 2) by connecting to each other the material layer (1) positioned on top in at least one other position, preferably approximately alongside a second longitudinal edge (4) or transverse edge (4a) of the material layer above (1, 1a, 1b, 1n), or preferably approximately alongside a line parallel to the edge, and
• the multi-layer pipe (5) is then finish-shaped by means of the bending roller and/or bending machine, with the material layers (1, 2) shifting no more against each other now during this finish-shaping, so that as a result, the material layer (1) acting as an internal pipe is pressed non-positively into the material layer (2) acting as an external pipe.