Method of detecting when an optical preform MCVD tube is completely closed
AssigneeAlcatel
InventorsJean-François Regnier, Gérard Orcel
Life of this patent
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Abstract
A method of detecting a critical state of closing of a preform during a phase of closing of the preform following a phase of deposition of layers of material that reduce the radial size of an opening formed in the preform smaller in the radial direction comprises the steps of injecting a gas into the opening, measuring a pressure in a pipe element through which the injected gas flows and detecting the critical state of closing of the optical preform on the basis of a measured pressure.
Claims4
A method of detecting when a preform is completely closed, comprising steps of:
- after completion of a deposition phase for forming the preform, injecting a gas through a pipe and into an opening in the preform in a closing phase;
- measuring a pressure of the gas in the pipe during the closing phase;
- and
- detecting that the optical preform is completely closed when the pressure measured in said measuring step is greater than a predetermined threshold.
A method of detecting a critical state of closing of a preform, comprising steps of:
- after completion of a deposition phase for forming the preform, injecting a gas through a pipe and into an opening in the preform in a closing phase;
- measuring a pressure of the gas in the pipe during the closing phase;
- and
- detecting the critical state of closing of the optical preform when the pressure measured in said measuring step is greater than a predetermined threshold.
Dependencies are inferred from the claim text.