Heating furnace for the internal coating of preforms for optical waveguides

摘要

In a mobile heating furnace for the internal coating of substrate tubes for optical waveguides, one or more seals (gaskets) are provided between the substrate tube and the inner wall of the heating furnace in order to seal off the interspace. The seals have an opening for the substrate tube, the diameter of which opening is smaller than the outer diameter of the substrate tube, and slots extending radially from the inside outward.