| 摘要 |
PROBLEM TO BE SOLVED: To prolong the service life of a quartz core tube in a sintering apparatus for a porous perform and to reduce the cost. SOLUTION: The sintering apparatus is for dehydrating and transparently vitrifying the porous perform, uses an electric furnace as a furnace body and has the quartz furnace core tube 1, in which the porous perform is housed, a heater and a carbon furnace core tube 2 between the heater and the quartz furnace tube 2 and the distance between the quartz furnace core tube 1 and the carbon furnace core tube 2 is controlled to be larger than 3% of the outside diameter of the quartz furnace core tube and equal to and below 7%. |
