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Extrusion apparatus for conductor wire in which a core tube for guiding the wire is controllably movable axially so as to adjust the cross-sectional area of the flow passage for molten polymeric dielectric material moving towards the die orifice. The use of the adjustable core tube minimizes the deg

Extrusion apparatus for conductor wire in which a core tube for guiding the wire is controllably movable axially so as to adjust the cross-sectional area of the flow passage for molten polymeric dielectric material moving towards the die orifice. The use of the adjustable core tube minimizes the degree of draw down of the conductor wire.

대표청구항 ▼

Apparatus for insulating an electrical conductor wire comprising an extruder cross-head having an extrusion die defining a die orifice, internal wall means defining a flow passage for directing molten polymeric dielectric material to the die orifice, a core tube within the cross-head and upstream fr

Apparatus for insulating an electrical conductor wire comprising an extruder cross-head having an extrusion die defining a die orifice, internal wall means defining a flow passage for directing molten polymeric dielectric material to the die orifice, a core tube within the cross-head and upstream from the die orifice, the core tube defining a guide passage for directing the conductor wire through the die orifice as it moves along a passline, mounting means for the core tube to render it adjustable into any desired position along the passline, drive means operably connected to the core tube to controllably adjust the distance between the core tube and the wall means and thereby adjust the cross-sectional area of the flow passage, a monitoring means downstream from the cross-head for monitoring a parameter indicative of the thickness of the conductor wire when covered with the insulation layer, and an analyzing and control means to analyze monitored values received from the monitoring means and for controlling the position of the core tube along the passline, said means operable upon a monitored value differing from that required for a desired thickness of conductor wire to actuate the driving means and move the core tube in the appropriate direction to change the conductor wire thickness towards that desired. A method of insulating an electrical conductor wire comprising: passing the wire along a passline through a core tube in a cross-head and then through a die orifice of an extrusion die of the cross-head while extruding a molten polymeric dielectric material around the wire; monitoring a parameter indicative of the thickness of the wire at a position downstream from the cross-head to determine whether the wire thickness differs from that desired; and upon any monitored value differing from that required for a desired conductor wire diameter, controllably moving the core tube in an appropriate direction along the passline and into a desired position so as to controllably adjust the distance between the core tube and an internal wall means of the cross-head which defines a flow passage for directing molten polymeric dielectric material to the die orifice and thereby adjusting the effective cross-sectional area of the passage to cause the thickness of the wire to approach that desired.