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US 7,062,942 B2Granted
Method of manufacturing glass optical fibre preforms and optical fibres
AssigneePirelli & C. S.p.A.
InventorAnna Zilnyk
Life of this patent
Estimating the term…
Abstract
A method of making an optical fibre including providing an increased diameter portion on a rod. The rod is assembled by positioning the rod in a tube such that an annular gap is defined between an outer surface of the rod and an inner surface of the tube, and such that the increased diameter portion of the rod engages the tube and supports the rod with respect to the tube, and supporting the rod and tube assembly by gripping the tube. At the lower end of the rod and tube assembly, portions of the tube are collapsed onto the rod such that the tube portions fuse to the rod forming collapsed portions of the rod and the tube assembly. The collapsed portions are drawn to form an optical fibre. The vertically oriented rod and tube assembly can also be collapsed to form an optical fibre preform.
Claims21
A method of making an optical fibre comprising the steps of:
- a) providing an increased diameter portion on a glass rod, said glass rod including an outer longitudinal surface and a predetermined diameter;
- b) positioning said rod within a glass tube defined by a peripheral glass wall having an internal and an external surface, respectively, wherein said glass tube has an internal diameter which is greater than said predetermined diameter of said rod and, at least in a portion thereof, smaller than the diameter of said increased diameter portion of the rod, thereby causing said increased diameter portion of the rod to be in engagement with said tube;
- c) vertically positioning and mechanically supporting said tube to provide a vertically oriented rod and tube assembly including an upper end zone and a lower end zone, wherein said mechanically supporting of said tube and said engagement of said increased diameter portion of the rod with said tube are carried out in a respective portion of the upper end zone of said assembly, thereby causing said rod to be vertically supported within said tube by said increased diameter portion engaging said tube and to define an annular gap between the outer surface of said rod in the non-increased diameter portion thereof and the internal surface of said tube;
- d) providing a passage in said upper end zone of the assembly, below said increased diameter portion of the rod, in order to allow a fluid contained in said gap to flow out from said gap wherein said passage in said upper end portion of the assembly is provided on the wall of said tube, said passage having a first end opening on the internal surface of said tube into said annular gap and a second end opening on the external surface thereof towards the outside of said assembly;
- e) thermally collapsing said tube onto said rod at the lower end zone of the rod and tube assembly, such that at least a portion of said tube fuses to said rod;
- and
- f) drawing an optical fibre from said collapsed portion of said rod and tube assembly.
4 more elements
A method of making an optical fibre preform, comprising the steps of:
- a) providing an increased diameter portion on a glass rod, said glass rod including an outer longitudinal surface and having a predetermined diameter;
- b) positioning said rod within a glass tube defined by a peripheral glass wall having an internal and an external surface, respectively, wherein said glass tube has an internal diameter which is greater than said predetermined diameter of said rod and, at least in a portion thereof, smaller than the diameter of said increased diameter portion of the rod, thereby causing said increased diameter portion of the rod to be in engagement with said tube;
- c) vertically positioning and mechanically supporting said tube to provide a vertically oriented rod and tube assembly including an upper end zone and a lower end zone, wherein said mechanically supporting of said tube and said engagement of said increased diameter portion of the rod with said tube are carded out in a respective portion of the upper end zone of said assembly, thereby causing said rod to be vertically supported within said tube by said increased diameter portion engaging said tube and to define an annular gap between the outer surface of said rod in the non-increased diameter portion thereof and the internal surface of said tube;
- d) providing a passage in said upper end zone of the assembly, below said increased diameter portion of the rod, in order to allow a fluid contained in said gap to flow out from said gap wherein said passage in said upper end portion of the assembly is provided in said rod, said passage having a first end opening into said annular gap and a second end in fluid connection with the outer ambient of said assembly;
- and
- e) thermally collapsing said tube onto said rod at the lower end zone of the rod and tube assembly, such that at least a portion of said tube fuses to said rod.
3 more elements
A method of making an optical fibre preform, comprising the steps of:
- a) providing an increased diameter portion on a glass rod, said glass rod including an outer longitudinal surface and having a predetermined diameter;
- b) positioning said rod within a glass tube defined by a peripheral glass wall having an internal and an external surface, respectively, wherein said glass tube has an internal diameter which is greater than said predetermined diameter of said rod and, at least in a portion thereof, smaller than the diameter of said increased diameter portion of the rod, thereby causing said increased diameter portion of the rod to be in engagement with said tube;
- c) vertically positioning and mechanically supporting said tube to provide a vertically oriented rod and tube assembly including an upper end zone and a lower end zone, wherein said mechanically supporting of said tube and said engagement of said increased diameter portion of the rod with said tube are carried out in a respective portion of the upper end zone of said assembly, thereby causing said rod to be vertically supported within said tube by said increased diameter portion engaging said tube and to define an annular gap between the outer surface of said rod in the non-increased diameter portion thereof and the internal surface of said tube;
- d) providing a passage in said upper end zone of the assembly, below said increased diameter portion of the rod, in order to allow a fluid contained in said gap to flow out from said gap;
- and
- e) thermally collapsing said tube onto said rod at the lower end zone of the rod and tube assembly, such that at least a portion of said tube fuses to said rod,
- wherein said tube includes a handle portion and said increased diameter portion of said rod engages said tube handle portion,
- wherein said tube handle portion comprises two tubular elements joined in end-to-end relationship, a first of said tubular elements defining an internal surface having a first internal diameter greater than the predetermined diameter of said rod and smaller than the diameter of the increased diameter portion of said rod and a second of said tubular elements defining an internal surface having a second internal diameter which is greater than said first internal diameter and greater than the diameter of the increased diameter portion of said rod, said second tubular element being disposed axially outwardly of said first tubular element so as to define an end of said tube.
5 more elements
A method of making an optical fibre preform, comprising the steps of:
- a) providing an increased diameter portion on a glass rod, said glass rod including an outer longitudinal surface and having a predetermined diameter;
- b) positioning said rod within a glass tube defined by a peripheral glass wall having an internal and an external surface, respectively, wherein said glass tube has an internal diameter which is greater than said predetermined diameter of said rod and, at least in a portion thereof, smaller than the diameter of said increased diameter portion of the rod, thereby causing said increased diameter portion of the rod to be in engagement with said tube;
- c) vertically positioning and mechanically supporting said tube to provide a vertically oriented rod and tube assembly including an upper end zone and a lower end zone, wherein said mechanically supporting of said tube and said engagement of said increased diameter portion of the rod with said tube are carried out in a respective portion of the upper end zone of said assembly, thereby causing said rod to be vertically supported within said tube by said increased diameter portion engaging said tube and to define an annular gap between the outer surface of said rod in the non-increased diameter portion thereof and the internal surface of said tube;
- d) providing a passage in said upper end zone of the assembly, below said increased diameter portion of the rod, in order to allow a fluid contained in said gap to flow out from said gap,
- wherein said increased diameter portion sealingly engages said tube;
- and
- e) thermally collapsing said tube onto said rod at the lower end zone of the rod and tube assembly, such that at least a portion of said tube fuses to said rod.
4 more elements
Dependencies are inferred from the claim text.