| 摘要 |
PROBLEM TO BE SOLVED: To actualize uniform temperature distribution on the whole surface of a core portion 2 even when hot water flows at an extremely low rate. SOLUTION: A fluid passage in one upper side header tank 5 is formed in a double layer structure in the longitudinal direction of tubes 3, where a fluid inflow portion 7 and a fluid outflow portion 8 are provided in one outside fluid passage 5A and in the other inside fluid passage 5B, respectively. The tubes 3 are of two long and short types, and one long tube 3A communicates the outside fluid passage 5A with a turn-around fluid passage 6A in the other lower side header tank 6 and the other short tube 3B communicates the inside fluid passage 5B with the turn-around fluid passage 6A. The long tube 3A and the short tube 3B are approximately alternately arranged in the layering direction. The whole core portion 2 is divided into small blocks to wholly uniform a blow-off temperature even when a slight temperature gradient occurs in each U-turn portion. This actualizes uniform temperature distribution on the whole surface of the core portion 2 even when hot water flows at an extremely low rate. COPYRIGHT: (C)2006,JPO&NCIPI
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