| 摘要 |
<p>A thermally actuated radiator valve includes a positive temperature coefficient thermistor (22) and a thermally responsive unit (17) including a mass (20a) of thermally expansible semisolid material packed in a casing (18) and heated by the PTC thermistor to expand to drive a piston rod (20) inserted in the casing. The movement of the piston rod is transmitted to a valve member (8) to open the valve. A negative temperature coefficient thermistor (24) is mounted on the casing (18) in thermally conductive relation, to detect the displacement of the valve member in terms of the temperature of the thermal unit. A control circuit (Fig. 5 not shown) is responsive to the detected displacement of the valve member to energise the PTC thermistor so as to put the valve member at a desired position. The control circuit includes a further NTC thermistor (37) for sensing room temperature. <IMAGE></p> |
