| 摘要 |
<p>The invention relates to a conduit comprising a tube of plastics material (11) and a barrier layer (14) therefore characterised in that the barrier layer is bonded to the plastics material at longitudinally spaced intervals along the tube. The specification describes a method of producing the conduit by advancing a tube of plastics material and barrier layer therefore, forming the barrier layer about the tube, sealing the overlapping edges of the barrier layer to enclose the tube and then bonding the barrier layer to the tube at said spaced intervals. The invention also describes apparatus for conducting the method of the invention in which a carriage advances with the tube to effect a bonding operation and at the end of the period of bonding the carriage is released from the tube to return to the datum positions as the tube is continually advanced through the apparatus.</p> |
