JOINING LINED PIPE ITEMS.

摘要

Steel pipe items such as pipes (10) are each joined by a girth weld (14) to tubular steel fittings (12) and the pipes (10) are each lined by pulling a polyethylene liner (30) through a die and through the pipe (10) and through the fitting (12). A stainless steel ring (32) is forced into each fitting (12) to compress the liner (30) and force it into grooves (20) in the internal surface of the fitting (12). The grooves (20) are separated by castellations (22). The grooves (20) are machined in a corrosion-resistant cladding (18) deposited on the interior of each fitting (12). Alternatively, the whole of each fitting (12) is made of corrosion-resistant Duplex steel. The ends of the liners (30) are cut short of the ends of the fittings (12) and an annulus (40) of liner material is inserted in the gap. The annulus (40) has an external groove (42) accommodating a body (44) of heat insulation material. The ends of the fitting (12) are drawn together and joined by a girth weld (15).