TUBULAR PLASTIC ARTICLE CAPABLE, AFTER NON-ELASTIC DEFORMATION, TO RECOVER ITS ORIGINAL SHAPE AND SIZE BY HEATING IT

摘要

A dimensionally heat recoverable tubular article (1) is made by spirally wrapping cross-linked polymeric sheet (3) a number of times, and directly fusing together overlapping layers (5) of the cross-linked sheet (3) to form a consolidated tubular article. The final article has a wall thickness of at least 2.2 mm. Articles according to the invention may be made of different diameter and different wall thickness, starting from the same thickness initial sheet material, simply by changing the circumference of wrapping or the number of spiral wraps. Articles according to the invention are particularly useful as casings over joints between district heating pipes.