Patent DE-102009013248-A1 (DE)
Title: Method for the production of a connection tube for indoor installation, comprises forming an interiorly lying polymer tube having a layer of binding agent at its external surface and bending a tubular metal foil
Inventor: KUHN MAREN
IPC: F16L9/147
Filed: 2009-03-14
Abstract: The method comprises forming an interiorly lying polymer tube (1) having a layer of bonding agent (2) at its external surface, bending a tubular metal foil (3) in such a way that the longitudinal edges of the metal foil overlap to each other, forming a welding seam (4) running in longitudinal direction for forming a closed tube in the area of the overlapping through laser welding, melting the bonding agent arranged on the external surface of the interiorly lying polymer tubes through an additional heating, and connecting the polymer tube completely with the metal foil. The method comprises forming an interiorly lying polymer tube (1) having a layer of bonding agent (2) at its external surface, bending a tubular metal foil (3) in such a way that the longitudinal edges of the metal foil overlap to each other, forming a welding seam (4) running in longitudinal direction for forming a closed tube in the area of the overlapping through laser welding, melting the bonding agent arranged on the external surface of the interiorly lying polymer tubes through an additional heating, and connecting the polymer tube completely with the metal foil through subsequent solidification of the bonding agent. The metal foil is formed to a closed tube through the production of the welding seam passing in longitudinal direction before the polymer tube is connected through the solidification of the bonding agent completely with the metal foil. The metal foil is applied before the laser welding in order to form the polymer tube. The additional heating is carried out for melting the bonding agent after the laser welding. The laser welding is directly carried out after the additional heating of the bonding agent before the polymer tube and the metal foil are connected. A diffusion barrier layer is applied on the polymer tube through thin layer process and consists of a metal, metal alloy, metal oxide or amorphous carbon. The tube closed at circumference side is formed from metal foil and the bonding agent layer and the polymer tube are injected subsequently on the interior side of the tubes. The tubes formed from the metal foil are compacted with the polymer tube and an externally lying polymer tube (5) is extruded on the tube formed from the metal foil. The welding seam is produced through a disk laser. The welding seam is formed during laser welding with a width of 0.3 mm in such a way that the overlapping layers of the metal foil form a complete material connection, are melted to each other, and are subjected in the area of the welding seam, to a structural transformation that extends itself over the total thickness of the layers. The interiorly lying polymer tube is formed from cross-linked polyethylene or polyethylene with high temperature stability. The metal foil consists of aluminum or aluminum alloy and has a thickness of 100-1500 mu m. The metal foil is inductively heated for additional heating.