A method for protecting the joints of aluminium sheathed underground tubing has a reinforced polypropylene muff having embedded heating coils to electrically weld the muff to the protective insulated sleeving of the tubing

摘要

The plastic connection tubing (1) has an aluminium outer coating (3) which is insulated from the earth by a polypropylene sleeve (2) and where two sections of tubing are joined the joint is protected by a reinforced polypropylene sleeve with separate electrical heating coils (4,5) near each end with terminals (7,8) by which a weld is is formed to the protective sleeving.