| 摘要 |
PURPOSE: A method for preparing a silica tube is provided, to obtain a ceramic tube such as a silica overcladding tube having a very little bow of about 0.3 mm per meter or less. CONSTITUTION: The method comprises the steps of inserting a handle front end(22) into the internal cavity of a tube(10); inserting a silica pin(30) therein; fixing the relative terminal of a handle by a knob(40), to allow the tube to be perpendicularly hung down; keeping the tube/handle assembly parts at a temperature suitable for removing all of the remaining impurities; raising the temperature of the assembly parts by passing the parts through the hot region of a furnace, to allow the entire part of the tube to be fired and the furnace to be heated generally to a sintering temperature; and passing the tube through the hot region and returning it by pulling up. The handle front end(22) and the tube(10) are deformed by a high temperature but the handle front end(22) is applied with force and has a tendency to be deformed in the array symmetrically perpendicularly to the tube which maintains perpendicularity by the occurrence of the bow.
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