IMPROVEMENTS IN AND RELATING TO THE APPLICATION TO A STEEL PIPE OF A COATING OF THERMOPLASTIC SYNTHETIC MATERIAL

摘要

1,249,931. Covering pipes by winding. MANNESMANN A.G. 4 July, 1969 [5 July, 1968], No. 33710/69. Heading B8G. [Also in Division F2] A tape 5 of thermoplastic material is wound helically on to a heated rotating steel pipe 1 in overlapping convolutions whilst simultaneously a ribbon 3 of adhesive material is wound on to the pipe 1 beneath the leading edge of the tape, the ribbon width being less than the tape width and not less than the pitch of the windings. Both tape and ribbon may be extruded from slits 7, 4 in extruder heads 6, 2 adjacent the pipe, and the tape may be pressed into contact with the adhesive ribbon before contact with the pipe by means of a roller 8. The elevated temperature of the pipe welds the layers of tape together.