SURFACE TREATMENT OF QUARTZ PIPE

摘要

PURPOSE:To finish the inside surface of a quartz pipe for production of a base material for an optical fiber to a smooth surface without the intrusion of impurities such as OH group from the inside surface thereof by heating the inside surface of said pipe by an electrical heating method thereby smoothing the inside surface. CONSTITUTION:Foam, etc., arise in the formed base material and the quality of the optical fiber produced therefrom is deteriorated if the inside surface of the quartz pipe has flaws or decomposition of impurities in the stage of producing the base material for the optical fiber by depositing the glass layer on the inside surface of the quartz pipe. The inside surface of the quartz pipe must be finished to the smooth surface in order to prevent the above-mentioned deterioration and therefore a coil 12 for high-frequency induction heating is attached to the outside circumference of the quartz pipe 11 and a heating element 13 made of the carbon rod is kept inserted into the pipe 11. The high-frequency current is passed to the coil 12 and the heating element of the carbon rod is heated inductively to smooth the inside surface of the pipe 11 by the heat thereof. Since the quartz pipe is electrically heated, the intrusion of defective elements such as OH group to the inside surface of the quartz pipe as in the case of heating by oxyhydrogen flame is obviated.