Patent ID: 9618197
Date: 2017-04-11
CPC Classifications: F22B

Claim:
1. A boiler system comprising a boiler group including at least three boilers each configured to combust at a varied load factor which represents a rate of an amount of combustion with respect to a maximum amount of combustion of a boiler, and a controller for controlling a combustion state of the boiler group in accordance with an amount of steam required by a user apparatus, wherein the controller includes a determiner for determining a heat releasing boiler configured to determine that a heat releasing boiler exists among the plurality of boilers, the heat releasing boiler being at rest and releasing heat obtained during the heat releasing boiler having been in combustion, a boiler increase determiner configured to determine whether or not a load factor, at which the heat releasing boiler resumes combustion and other boilers in combustion continue combustion, such that a first total amount of steam supplied by the heat releasing boiler after resumption of combustion and the other boilers in combustion is the same as a second total amount of steam having been supplied by the other boilers in combustion prior to the resumption of combustion of the heat releasing boiler, is higher than a predetermined load factor value, and an output controller configured to cause the heat releasing boiler to resume combustion when the determiner determines that the heat releasing boiler exists among the plurality of boilers even if the other boilers in combustion maintain a margin in excess of reserve power corresponding to a varied steam flow which allows the other boilers to briefly increase an output of steam in response to a sudden load variation and the boiler increase determiner determines that the load factor is higher than the predetermined load factor value, wherein the predetermined load factor value of each of the plurality of boilers is configured to fall in a highly efficient zone corresponding to a range where each of the plurality of boilers combusts efficiently, and to be a predetermined amount higher than a boiler number decreasing load factor which is used as a stop reference threshold according to which the controller determines whether to stop each of the plurality of boilers.