| 摘要 |
<p>Provided is a heat exchanger wherein the generation and adhesion of scale can be suppressed while the heat transfer coefficient is improved, and the life span is enhanced. In a heat exchanger (10), throttle passages (37, 47), sectional areas of which are smaller than those of other portions, are provided between an upstream-side space (25a) and a downstream-side space (25b), and a planar heater (20) is formed so that the heating density of the side of the planar heater, which is close to a water outlet port (25b), is lower than the heating density of the side of the planer heater, which is close to a water inlet port (25a). Thus, while the heat transfer coefficient is improved, the temperature of a cleaning water is prevented from increasing to a temperature at which a boiling phenomenon may locally occur even in a boundary layer between the side of the planar heater (20), which is close to the water outlet port (25) at which the temperature of the cleaning water tends to increase and the cleaning water which is in contact with the water outlet port-side of the planar heater. As a result, the generation of bubbles is suppressed, and generated bubbles are rapidly led to the water outlet port (25b). Thus, scale is prevented from being generated in and attached to the planar heater (20), and a heat exchanger having a long life span can be provided.</p> |
