Manufacture of insulated electric cables

Abstract

Abstract A COMPOSITE COVERING COMPRISING AT LEAST TWO LAERS OF DIFFERENT COVERING MATERIALS IS EXTRUDED ON A CONTINUOUSLY ADVANCING CORE BY PASSING THE CORE THROUGH THE CORE TUBE OF AN EXTRUSION MACHINE WHICH FEEDS EXTRUDED, PERIPHERALLY CONTINUOUS LAYERS OF THE COVERING MATERIALS SIMULTANEOUSLY TOWARD THE OUTLET END OF THE EXTRUSION MACHINE AND CAUSING THE EXTRUDED LAYERS TO COME INTO COMPLETE AND INTIMATE INTERFACIAL CONTRACT UPSTREAM OF THE OUTLEN END OF THE EXTRUSION MACHINE. THE COMPOSITE COVERING SO FORMED IS TREATED, E.G. CURED, CONTINUOUSLY BY PASSING THE COVERED CORE THROUGH A CHAMBERHERMETICALLY SEALED TO THE OUTLET END OF THE EXTRUSION MACHINE AND CONTAINING A FLUID MEDIUM AT SUPER-ATMOSPHERIC PRESSURE. AT THE SAME TIME, FLUID UNDER PRESSURE IS INJECTED INTO THE INTERIOR OF THE CORE TUBE AND IS MAINTAINED AT A PRESSURE LESS THAN THAT OF THE FLUID MEDIUM BY AN AMOUNT SUCH THAT THE PRESSURE DIFFERENCE ACROSS THE EXTRUDED COMPOSITE COVERING AT THE EXTRUSION ORIFICE IS SUFFICIENT TO CAUSE THE EXTRUDED COMPOSITE COVERING TO COLLAPSE FIRMLY ON TO THE CORE AS IT EMERGES FROM THE EXTRUSION MACHINE.

Inventors

• 👤 P Nicholson

Bibliographic Details