External sheathing of metal heat exchanger tubes - partic. with PTFE uses lapping followed by sintering by inductive heating of tube at medium frequency, in continuous operation on moving and rotating tube.

摘要

An external sheath is made on a metal tube, partic. a heat exchanger tube which is moved continuously forward along its axis through a lapping stage where a fluorinated resin, partic. PTFE, tape (8) is wound on the tube (1). A sintering stage, after lapping, heats the tube (1) by induction featuring (9), at frequency between 10-100 KHz. USE/ADVANTAGE - Prodn. of external sheath on metal heat exchanger tubes subjected to aggressive chemicals. Relatively simple and economic method of producing long sheathed tubes.