Muffle tube inspection method and manufacturing method of silica glass-based optical fiber preform
US8978421B2 · kind B2 · utility
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Key dates
| Filing date | Dec 11, 2012 |
| Grant date | Mar 17, 2015 |
| Priority date | — |
| Expiry date | May 15, 2033 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P40/57
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A muffle tube inspection method inspects a muffle tube used for dehydrating and sintering a silica glass-based optical fiber preform, the muffle tube includes a sintering furnace provided with a furnace body covering a heater disposed around a periphery of the muffle tube. The method detects a crack generated at the muffle tube by measuring a pressure inside the furnace body while varying a pressure inside the muffle tube.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.