| 摘要 |
1,221,286. Making coated tubes; rolling tubes. ALLIED TUBE & CONDUIT CORP. 3 March, 1969 [13 March, 1968], No. 11173/69. Headings B3A and B3M. In a method and apparatus for making colour coated galvanized tube a metal strip, preferably steel, is formed into a tube which is then galvanized, preferably with zinc by dipping in molten metal, coated with a colour composition straightened and cut into lengths. After galvanizing the tube passes through sizing and straightening rolls 200, 202 into a drying chamber 204 to remove any moisture on the tube then the colour coating (see Heading B2K) is applied, preferably by the electrostatic spraying technique. After baking 222 to harden the coating the tube is cooled 231 and passes into driving rolls 224, 226. The rolls are preferably metal rolls having hard rubber or plastic layers which engage the tubing to avoid marring the coating. After straightening 242 the tubing is cut to lengths by a flying shear 244. |
