A method of and an apparatus for the internal coating of ducts with a synthetic resin, especially long steel pipes or tubes, in which gas-entrained synthetic-resin particles are passed through the tube while the latter is heated progressively by displacing the tube relative to a surrounding induction-heating...http://www.google.fr/patents/US3946125?utm_source=gb-gplus-shareBrevet US3946125 - Method for internally coating ducts with synthetic resin
Method for internally coating ducts with synthetic resin
