Blowing hot gas through pipe to remove entrained air in thermosetting plastic lining material

Abstract From the Canadian patent

A method of lining a pipe with thermosetting synthetic plastics material including the steps of arranging the pipe with its longitudinal axis inclined at an acute angle to the horizontal, introducing liquid lining material into the pipe at a predetermined rate for a predetermined time, shifting the pipe to a horizontal position shortly before or at the completion of introduction of the liquid material spinning the, pipe about its axis and blowing hot air axially through the pipe after spinning has started but before the lining material has set thereby to remove entrained air bubbles. The method is particularly applicable for lining pipes with polyurethane, especially pipes with end flanges …