Methods of and apparatus for at least partially closing an end portion of an optical preform tube
US4601740A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 18, 1984 |
| Grant date | Jul 22, 1986 |
| Priority date | — |
| Expiry date | Dec 18, 2004 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03B37/01869
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A preform from which lightguide fiber is drawn is made by depositing optically suitable layers of doped silicon dioxide on an inner wall of a rotating glass tube (31) which is exposed to a moving zone of heat (56) which is provided by a torch assembly (50) during a deposition mode and during a collapse mode. After the deposition mode and generally prior to the collapse mode, one end portion of the tube is at least partially closed in order to allow pressurizing of the tube during collapse. This is accomplished with a pivotally mounted tool (70) which straddles the torch assembly to cause an internally water cooled contact device (92) to be disposed within the confines of the torch. Further, the contact device is configured to provide a curved lead-in from the tube to the at least partially closed portion. The use of separate apparatus for initially closing the tube provides control of the sealed-off portion and prevents an irregular cross-section from being propagated along the length of the tube.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.