| 摘要 |
<p>A valve unit 1 has an input port 2 and a valve member 7 movable between two outputs 3, 4. The valve member is normally held against the first output by springs 8. A shaft 5 rotatable by a motor 9 moves the valve member towards the second output 3. Two thermostats 20, 24 sense temperatures at different points (e.g. domestic and radiator water). A triac 33 when triggered by low temperature at the second thermostat supplies the motor with A.C. current to open port 4. Motor driven switches 12, 13 are arranged so that a rectifier 35 supplies D.C. to the motor to lock the valve with both outlets open when both thermostats sense low temperatures. A demagnetizing current via a resistor 37 releases the motor. <IMAGE></p> |
