PURPOSE:To provide heat resistance and impact resistance and high temperature resistant stability, to shorten a dry distillation time, and to improve quality by a method wherein a burner nozzle is formed by mullite ceramics, and the surface thereof is covered with ceramic fibers consisting mainly of alumina and silica. CONSTITUTION:In a mullite ceramics nozzle having a tip 1 inserted through an oven wall 2 into a combustion chamber 3, the outer peripheral part of the tip part is covered with a ceramic fibers 4 consisting mainly of 70wt% or more alumina and the rest of silica. The base end thereof is secured for sealing to the base part of an inner cylinder 6, at which a packing box 5 is formed, through a gland packing 7. The vicinity of the middle part thereof is supported to the inner cylinder 6 through a spacer 8. Bulklike state or a feltlike state may be recommended as the form of ceramic fibers, and a substance formed in a blanketlike state or a substance molded in a feltlike state by using an inorganic binder may also be recommended. Since wet felt has flexibility and can be bent is a free shape before dry and is cured in a rigid state after dry, installation is easy to make.
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