| 摘要 |
In the manufacture of mineral insulated cable, by a continuous process in which the tubular sheath is formed by bending and seam welding travelling metal strip, and insulating powder and conductor wires are continuously delivered into the sheath, one wire is fed through a guide tube extending into the sheath beyond the weld point, and having an aperture in its wall adjacent to the weld area. The wire so exposed directly to the heat from the weld conducts excess heat away from the weld, thus preventing thermal damage, in particular to a powder delivery tube if present. The guide tube is so arranged that powder is excluded from the weld area. When the sheath is formed of an oxidizable metal such as copper, a continuous stream of rare gas is delivered to the underside of the weld area. Forms of apparatus for carrying out vertical and horizontal processes are described. |
