| 摘要 |
PURPOSE:To prevent the occurrence of a trouble on a vaporizing pipe through supply of water circulating capacity when an unexpected state, e.g., so-called soot fire, occurs by a method wherein, in a natural circulation type boiler, a bypass line is installed to a precipitation pipe system, a circulating pump is mounted in the bypass line, and a stop valve is provided in the precipitation pipe system. CONSTITUTION:During normal operation, a stop valve 11 is brought into a fuel opening state and natural circulation type operation is effected. But, when the temperature of, for example, an exhaust gas outlet 9 is increased abnormally, the increased temperature is detected by a sensor 14 and the stop valve 11 is fully closed by means of a signal line 15. A circulating pump 13 is started to ensure circulation of water in a vaporizing pipe 6, and the trouble, e.g., seizure, of the vaporizing pipe 6 is prevented from occurring. |
