GB276390A - Improvements in methods and apparatus for coating metals with metal - Google Patents

Abstract

276,390. Marks, E. C. R., (American Machine & Foundry Co.). March 23, 1926. Coating.-In a method of coating metals with metal, the metal to be coatted, preferably in wire form, is passed continuously through a dhamber within which an atmosphere, containing the vapour of the coating metal is continuously produced and maintained at a sub-normal pressure, e.g., 10 inches of mercury. To assist the coating, the atmosphere containing the coating metal is subjected to a high electric potential, e.g., of approximately 2000 volts, in order to ionize the vapour. The coating chamber 1 surrounded by a vacuum chamber 26 is provided with an inlet 2 for the wire to be coated and an outlet 3 for the coated wire, the wire passing from the inlet 2 through a chamber 6 into the chamber 1 and out through a pipe 5 to the outlet 3. The vapour of the coating metal in the chamber 1 is produced by vapourizing the coating metal in a pot 9 which is heated by a coil 12 connected to rods 7, 8, which also support the pot 9 in the chamber 1, and which are connected to wires 7', 8<1>. An insulating graphite shield 13 is provided round the pot 9 which also has an aperture. 10 for the passage of the wire and the rods 7, 8 are impported by insulators 14 surrounded by cylinders 15 to prevent condensation of metal thereon. The upper end of the rod 8 is hollow and is connected at its upper end with a pipe 16 leading to a pot 17 containing coating metal and at the lower end of the hollow part with a pipe 19 leading to the pot. By this means the metal in the pot 9 may be replenished. To maintain the interior of the chamber 1 at the desired sub-normal pressure, a pipe 20 connected to the tube 5 is connected to a pump (not shown). To free. the atmosphere in the chamber from water vapour, a duct 21 is connected to the chamber 6 and also through a dehydrating chamber 22 to a suitable pump. The wire on entering the inlet 2 may be cleaned by a sand blast through a pipe 24 and the coated wire, may be cooled by a blast, of air through a pipe 25 connected to the outlet 3, and the blast through these pipes prevent the access of air to the chamber 1. The chamber 26 which acts as a heat insulator for the chamber 1 is provided with dehydrating means 28 connected to a pump and its top as well as that of the chamber 1 is cooled by water circulating through pipes 30. In order to ionize the vapour of the coating metal, the lead 31 of the high potential circuit is grounded on the chamber 26 at 32 and the other lead 33 enters through the rod 7 which is insulated by the insulator 14.