Apparatus for the manufacture of mineral insulated cables

Apparatus for the manufacture of mineral insulated electric cable which includes means for continuously bending a downwardly travelling strip of ductile metal into the form of a tube and means for seam welding the meeting edges of the bent strip, while the said edges are travelling along a vertically downward path, to form a tubular sheath, a powder delivery tube disposed vertically so as to be located within, and spaced from, the bent strip and formed sheath, and having its outlet end located at a level below that of the welding means, means for feeding powdered insulating material into the said powder delivery tube at a controlled rate, means for feeding at least one continuous length of conductor wire into the formed sheath, means for guiding each said wire into a desired position within the sheath, means for reducing the diameter of the formed sheath, in a plurality of stages, subsequently to the introduction of the insulant powder and each wire into the sheath, and means for annealing and quenching the sheath after each reduction stage, at least the first reduction and annealing means being located vertically below the sheath forming and welding means, wherein the said conductor wire feeding means is arranged to feed each length of wire vertically downwards in a predetermined location along the outside of the powder delivery tube, and the said means for guiding each said wire into a desired position within the sheath is located along the exterior of the powder delivery tube.