| 摘要 |
<p>PURPOSE:To restrict an increasing of a fed hot water temperature by a method wherein a flow rate controlling member comprised of a plurality of bi-directional shape memory alloy blades of which flow passage sectional area is small when the temperature is higher than a predetermined temperature and the flow passage sectional area is large when the temperature is lower than a predetermined temperature is arranged at an outlet part of a heat exchanger. CONSTITUTION:A flow rate limiting member 7 is arranged within a pipe of a heated fluid circulation passage 6 at an outlet port of a heat exchanger 2. The flow rate limiting member 7 is comprised of a plurality of tongue-like blades 71, 71... and each of the blades 71, 71... keeps a curved shape which is the same as that of flow along a flow passage as shown by a solid line under a normal condition of lower than a predetermined temperature, i.e. when the hot water feeding load is high and the hot water temperature does not exceed its upper limit value. When each of the blades 71, 71... is higher than the predetermined temperature, i.e. the hot water feeding temperature exceeds its upper limit value, if it exceeds a thermal medium water temperature in the heating fluid circulation passage 6 when the hot water feeding temperature exceeds its upper limit value, a bi-directional shape memory alloy which is deformed at a right angle in respect to the flow passage by being projected toward the center of the flow passage as indicated by a two-dotted line is formed. For example, when eight blades 71, 71... show a temperature higher than the predetermined temperature, the diameter of the flow passage is varied to DS and the temperature is lowered, the diameter is changed approximately to DL.</p> |
