| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a once-through boiler preventing the occurrence of troubles such as overheating of a heat transfer tube and carryover due to the loss of balance between combustion amount and water level in the heat transfer tube at the time of changing combustion amount. <P>SOLUTION: A water level is set at the middle of the heat transfer tube in the once-through boiler. A combustion amount of the boiler is set stepwise. The water level control range is changed over in accordance with the combustion amount. When the combustion amount is changed to a combustion state, the water level control range is changed over first. The change of combustion amount is performed a predetermined time period T behind the changeover of the water level control range, which prevents the overheating of the heat transfer tube and the occurrence of carryover due to the loss of balance between combustion amount and water level in the heat transfer tube. <P>COPYRIGHT: (C)2012,JPO&INPIT |
