| 摘要 |
PURPOSE:To make it possible to maintain a upper heat absorbing section side at a high temperature by using as burner provided at the lower part of a can body a forced combustion type burner, locating the heat absorbing section consisting of heat absorbing tube groups at the upper part of the can body, and forming a bypass circuit making a detour around the upper heat absorbing section, at the outer part of the can body. CONSTITUTION:As a lower burner 3 of a can body 2 a forced combustion type burner, and heat absorbing sections 1a and 1b consisting of the groups of heat absorbing tubes 11 and 11, at the upper part of the can body. A bypass circuit 4 making a detour around the upper heat absorbing section, is formed at the outer part of the can body 2. Since the burner 3 is of a forced combustion type, the temperature distribution in the section of the can body 2 is equalized, and the ambient temperature of the lower heat absorbing section becomes high in its entirety. While the ambient temperature of the upper heat absorbing section becomes low as compared with that of the lower heat absorbing section 1b, the bypass circuit 4 is provided in the heat absorbing section 1a, and the flow rate of a fluid to be heated through the heat absorbing section is reduced as compared with the heat absorbing section 1b. The temperature of the heat absorbing section becomes higher as the flow rate ratio of the bypass circuit 4 is made larger, thus preventing the generation of a drain. |
