| 摘要 |
PURPOSE:To obtain the titled burner capable of feeding a gasous raw material having low vapor pressure stably without causing condensation of the gas by a constitution wherein hollow parts are formed in partition walls separating plural passages, a heating medium is sealed therein, and the heating medium is heted by a heater. CONSTITUTION:In a burner 1A for forming a porous parent material for optical material having plural passages separated by plural partition walls 2, at least one partition wall 2 is formed to have a double wall structure interposing a hollow part 2c. Further, a heating medium housing part 4 is formed as a part of the hollow part 2c at an end 2a of the burner base formed to a larger dia., and a heating medium 3 comprising H2O and glycerin, etc. is sealed therein. Furthermore, a heater 5 for heating the heating medium is provided around said heating medium housing part 4. The heating medium 3 is heated and evaporated by the heater 5 and diffuses to the top end 2b through the hollow part 2c to heat the whole part of the partition wall 2. Thus, the feed gas passing through the passage 6 separated by the partition wall 2 is prevented from cooling, therefore, condensation of the feed gas is prevented even if the feed gas is one having low vapor pressure. |
