GB1192208A - Method and Apparatus for Continuous Coating of Metallic Products with Fusible Pulverulent Materials. - Google Patents

Abstract

1,192,208. Coating. ANCHOR POST PRODUCTS, Inc. 13 Oct., 1967 [2 Dec., 1966], No. 46876/67. Heading B2K. [[Also in Division D1] Metal articles e.g. wire are coated by continuously applying a pulverulent, flowing material in an unaerated compacted condition to the surface of the moving article and fusing the pulverulent material. Fig. 1B is a downward continuative of Fig. 1A. A wire W which has been cleaned of scale and grease by solvents pickling, or grit blasting is passed through a primer coating chamber 14 through which primer is passed by a pump 26. The primer is dried and cured in a tube 10 through which air from a blower 28 passes. The tube is heated by an induction coil 16 or by radiant, convertion or resistance heating. The wire then passes to a coating section 40 comprising a hopper 42 and an H-shaped coatercirculator 44. The arm 43 of the circulator 44 depends from the lowermost end of the hopper 42. The arm 45 of the circulator 44 extends to near the top of the hopper 42. Coating powder is introduced from time to time to hopper 42 through its cover 41. Recirculation of the powder is accomplished by air introduced at valved inlet 60 from blower 28. Another valved inlet 66 extends coaxially upward into the arm 45. A small portion of air is provided at an inlet 55 to prevent powder from entering the seal 52. From the arm 45 the powder and the air mixture enters the hopper 42 where separation takes place, the air escaping through an opening 72 and the powder filling the arm 43. The powder is compacted therein by electrically operated vibrators 100. Heat is removed from the coated wire by a long vertical travel. Steel wire may be coated with vinyl thermo plastic resin using a primer of thermosetting material in solvent and containing metal pigments higher in the electro motive series than iron. Steel wire may be coated with polyolefin thermoplastic such as polyethylene or polypropylene containing metal in flake or powdered form, metal oxide, hydroxides, metal carboxyl groups and including heat and ultra-violet stabilizers as well as pigments. The primer is a weak acid solution of a base metal higher in the electromotive series than iron. In the coating of steel wire with thermosetting material such as epoxy-polyamide containing pigments and stabilizers, the primer is a phosphate treatment. The articles to be coated may be any metal strip or web, filaments in other forms than wire such as flat coil, and tubing. The powder may also be maintained in a circulating condition by the use of a vacuum lift, mechanical life such as a screw conveyer or similar powder lifting device.