Method of continuous vulcanization in the presence of helium or hydrogen

Claim 1

A method of continuously vulcanizing a freshly extruded polymeric strand which comprises passing said strand through a zone wherein a gas selected from the group consisting of helium and hydrogen is disposed, simultaneously maintaining said gas under several atmospheres pressure and in relatively unchanging and stagnant state within said zone about said strand, transmitting to said strand by conduction through said gas heat sufficient to vulcanize said strand, and cooling said strand in a cooling area, said gas also serving as heat insulation against heat transfer between said cooling area to said zone.

Claim 2

A method of continuously vulcanizing a freshly extruded polymeric strand which comprises passing said strand through a zone wherein a gas selected from the group consisting of helium and hydrogen is disposed, simultaneously maintaining said gas under several atmospheres pressure and in relatively unchanging and stagnant state within said zone about said strand, transmitting to said strand by conduction through said gas heat sufficient to vulcanize said strand, and cooling said strand in a cooling area, said gas also serving as heat insulation against heat transfer between said cooling area to said zone.

Claim 4

A method of continuously manufacturing an electrical cable comprising feeding an electrically conducting core into an extruder and extruding thereon a polymeric layer of insulation, passing said cable through a first zone wherein said cable is immersed in a gas selected from the group consisting of helium and hydrogen under pressure and in relatively unchanging and stagnant state within said first zone, transmitting heat to cure said insulation layer to said cable by conduction through said gas, passing said cable through a second zone wherein said cable is cooled, said gas also serving as heat insulation against heat transfer between said first and second zones, and maintaining said cable in a catenary curve throughout heating and cooling and free from contact with adjacent surfaces until the cured insulation has hardened.

Claim 5

A method of continuously manufacturing an electrical cable comprising feeding an electrically conducting core into an extruder and extruding thereon a polymeric layer of insulation, passing said cable through a first zone wherein said cable is immersed in a gas selected from the group consisting of helium and hydrogen under pressure and in relatively unchanging and stagnant state within said first zone, transmitting heat to cure said insulation layer to said cable by conduction through said gas, passing said cable through a second zone wherein said cable is cooled, said gas also serving as heat insulation against heat transfer between said first and second zones, and maintaining said cable in a catenary curve throughout heating and cooling and free from contact with adjacent surfaces until the cured insulation has hardened.

Claim 6

A method of rapidly and continuously forming a vulcanized polymeric covering on an electric conductor which comprises continuously extruding an unvulcanized polymeric conductor about the conductor, continuously passing the resulting covered conductor through a vulcanizing zone wherein a relatively unchanging body of gas selected from the group consisting of helium and hydrogen is maintained under superatmospheric pressure and in relatively unchanging and stagnant state within said zone, heating said covering to vulcanizing temperature by conduction through said gas, and continuously supplying heat to said body of gas by maintaining said body in heat exchange solution with a surrounding flowing stream of a hot fluid, and cooling said covered conductor in a cooling area, said gas also serving as heat insulation against heat transfer between said cooling area to said zone.

Claim 7

A method of rapidly and continuously forming a vulcanized polymeric covering on an electric conductor which comprises continuously extruding an unvulcanized polymeric conductor about the conductor, continuously passing the resulting covered conductor through a vulcanizing zone wherein a relatively unchanging body of gas selected from the group consisting of helium and hydrogen is maintained under superatmospheric pressure and in relatively unchanging and stagnant state within said zone, heating said covering to vulcanizing temperature by conduction through said gas, and continuously supplying heat to said body of gas by maintaining said body in heat exchange solution with a surrounding flowing stream of a hot fluid, and cooling said covered conductor in a cooling area, said gas also serving as heat insulation against heat transfer between said cooling area to said zone.