| 摘要 |
PROBLEM TO BE SOLVED: To prevent water in a heat exchanger from being partially boiled due to the partial heating of water in a heat exchanger and to reduce a boiling noise by specifying the amount of the projection of the connection part between the end plate and smoke pipe of the heat exchanger of a hot water boiler to a combustion room side. SOLUTION: A connection part W1 between an end plate 9 and a smoke pipe 10 does not function as a fin even if a high-temperate combustion gas that flows from a combustion room 7 to the smoke pipe 10 contacts the connection part W1 by setting the amount of projection H1 toward the side of the combustion room 7 of the junction part W 1 to three times larger than a plate thickness t1 of the end plate 9 or less, or preferably as equal as it or less. Further, by setting the radius of curvature of a surface at a side that contacts the smoke pipe 10 of a projection part 9a where the end plate 9 projects toward the side of the combustion room 7 for joining the smoke pipe 10 to two times or larger than the plate thickness 11 of the end plate 9 or less, preferably as equal as it or less, no great gap is generated at the reverse side of the junction part W1 between the end plate 9 and the smoke pipe 10, thus preventing partial boiling phenomenon from occurring due to local heating of water near the junction part W1 within the heat exchanger 1. |
