Methods of and apparatus for heating a preform from which lightguide fiber is drawn
AssigneeWestern Electric Company, Inc.
InventorRama Iyengar
Life of this patent
Estimating the term…
Abstract
Apparatus for heating a vertically suspended preform from which lightguide fiber is drawn includes a torch having a plurality of ducts that open to a surface adjacent to a lower end of the preform. Fuel and oxidizing gases flow from the ducts, mix at the surface and flame about a necked-down, lower portion of the preform to form a melt cone from which the fiber is drawn. The ducts and the preform are positioned to cause a combustion zone of each flame to impinge upon the preform. In a preferred embodiment, the openings of the ducts are arrayed in a circle which is referred to as a pitch circle and which has a diameter that is less than that of the preform. Also, the ducts are arranged so that the gases are directed at a predetermined angle to the axis of the preform.
Claims20
A method of heating a glass preform from which lightguide fiber is drawn, said method including the steps of:
- supporting the glass preform with its axis oriented vertically, the glass preform having a necked-down portion at its lower end;
- directing a plurality of flames which are arrayed in a circle that circumscribes the preform toward a target surface of the necked-down portion at a predetermined angle to the axis of the preform to heat the preform, each of the flames including a precombustion zone, a combustion zone and a plume;
- positioning the target surface and the flames to cause the target surface to be engaged about its periphery by the combustion zones of the flames;
- and
- moving the glass preform downwardly at its lower end is heated while drawing lightguide fiber from the necked-down portion.
A method of heating a glass preform from which lightguide fiber is drawn, said method including the steps of:
- supporting the glass preform with its axis oriented vertically, the glass preform having a necked-down portion at its lower end;
- directing a plurality of gases from openings of ducts toward a target surface of the necked-down portion at a predetermined angle to the axis of the preform to produce a plurality of flames, each including a precombustion zone, a combustion zone and a plume, to heat the preform,
- positioning the ducts to array the openings in a circle which circumscribes the necked-down portion of the preform and which has a diameter that is less than the diameter of the preform to cause the target surface to be engaged about its periphery by the combustion zones of the flames;
- and
- moving the glass preform downwardly as its lower end is heated while drawing lightguide fiber from the necked-down portion.
A method of heating a substantially cylindrical glass preform from which lightguide fiber is drawn, said method including the steps of:
- supporting the glass preform with its axis oriented vertically, the glass preform having a necked-down portion at its lower end;
- positioning a plurality of supply ducts about the necked-down portion of the preform with openings of the ducts being disposed in a circle that has a diameter which is less than the diameter of the preform and being disposed at a predetermined angle to the axis of the preform;
- flowing gases through the ducts and causing them to produce a flame which impinges on the preform;
- and
- moving the preform downwardly as its lower end is heated while drawing lightguide fiber from a lower end thereof.
An apparatus for heating a glass preform from which lightguide fiber is drawn, said apparatus including:
- supporting means for holding the glass preform with its axis oriented vertically, the preform having a necked-down portion at its lower end;
- duct means having ends which are arrayed in a circle that circumscribes the preform for directing a plurality of flames toward a target surface of the necked-down portion at a predetermined angle to the axis of the preform to heat the preform, each of the flames including a precombustion zone, a combustion zone and a plume;
- positioning means for causing the target surface to be engaged about its periphery by the combustion zones of the flames;
- and
- moving means for advancing the preform downwardly as its lower end is heated while drawing lightguide fiber from the necked-down portion.
An apparatus for heating a glass preform from which lightguide fiber is drawn, said apparatus including:
- supporting means for holding the glass preform with its axis oriented vertically, the preform having a necked-down portion at its lower end;
- duct means including nozzles having orifices for directing a plurality of gases toward a target surface of the necked-down portion at a predetermined angle to the axis of the preform to produce a plurality of flames to heat the preform, each of the flames including a precombustion zone, a combustion zone and a plume;
- positioning means for mounting said nozzles with said orifices arrayed in a circle which circumscribes the necked-down portion of the preform and which has a diameter that is less than the diameter of the preform to cause the target surface to be engaged about its periphery by the combustion zones of the flames;
- and
- moving means for advancing the preform downwardly as its lower end is heated while drawing lightguide fiber from the necked-down portion.
An apparatus for heating a substantially cylindrical, glass preform from which lightguide fiber is drawn, said apparatus including:
- supporting means for holding the glass preform with its axis oriented vertically, the preform having a necked-down portion at its lower end;
- a housing which encloses a portion of a path of the drawn fiber, said housing including duct means for directing a flow of combustible gases toward the necked-down portion of the preform with openings of said duct means from which the gases emerge therefrom being arrayed in a circle having a diameter that is less than that of the preform;
- means for flowing gases through said duct means and causing them to provide flames to heat the preform;
- and
- means for moving the preform downwardly as its lower end is heated and for drawing lightguide fiber from the lower end thereof.
Dependencies are inferred from the claim text.