| 摘要 |
PROBLEM TO BE SOLVED: To prevent a fire caused by a burner and a burning damage and a crack caused by a thermal shock, by locating a casing made of a 40Ni-33Cr-3 Al material outside of an injection nozzle made of heat-resisting metal, and filling a heat insulating material in a space established between the tip portion of the injection nozzle and the casing. SOLUTION: A casing 12 made of a 40Ni-33Cr-3Al material is arranged outside of an injection nozzle 7 made of heat-resisting metal, and further, a space is provided at a tip portion which most readily suffers from a thermal shock. The space is filled with a heat insulating material 9 to prevent the tip of the injection nozzle 7 from suffering from a thermal shock caused by heating. Thus, by making the casing 12 with metal as well, which forms the outside of the double structure, it is possible to prevent damages at a connecting portion, which are caused by the difference of an expansion rate between the injection nozzle 7 and the casing 12. Further, when attaching to or detaching from a boiler body, the casing 12 can be prevented from being damaged by the contact thereto.
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