Boiler

A boiler, comprising:

• a plurality of inner water tubes arranged to form a cylindrical shape between an upper header and a lower header to constitute an inner water tube row;
• a plurality of outer water tubes arranged to form a cylindrical shape between the upper header and the lower header so as to surround the inner water tube row to constitute an outer water tube row;
• a plurality of inner longitudinal fins provided to close gaps between the adjacent plurality of inner water tubes except at a lower end of the inner water tube row;
• a plurality of outer longitudinal fins provided to close gaps between the adjacent plurality of outer water tubes except at an upper end of the outer water tube row;
• outer lateral fins provided on a surface constituting an inner peripheral surface of the outer water tube row in a predetermined region extending upward from an intermediate portion in a vertical direction of each of the plurality of outer water tubes;
• and
• a temperature sensor provided to one of a group including one of the plurality of outer water tubes, one of the plurality of outer longitudinal fins, and one of the outer lateral fins at a position corresponding to a lower end of the predetermined region.

A boiler, comprising:

• a plurality of inner water tubes arranged to form a cylindrical shape between an upper header and a lower header to constitute an inner water tube row;
• a plurality of outer water tubes arranged to form a cylindrical shape between the upper header and the lower header so as to surround the inner water tube row to constitute an outer water tube row;
• a plurality of inner longitudinal fins provided to close gaps between the adjacent plurality of inner water tubes except in one portion in a peripheral direction of the inner water tube row;
• a plurality of outer longitudinal fins provided to close gaps between the adjacent plurality of outer water tubes except in another portion in the peripheral direction of the outer water tube row;
• outer lateral fins provided on a surface constituting an inner peripheral surface of the outer water tube row in a predetermined region extending from an intermediate portion in the peripheral direction to the another portion in the peripheral direction of the outer water tube row;
• and
• a temperature sensor provided to one of a group including one of the plurality of outer water tubes, one of the plurality of outer longitudinal fins, and one of the outer lateral fins at a position corresponding to a side of one portion in the peripheral direction of the outer water tube row in the predetermined region.