| 摘要 |
<p>The calcification indicator uses two temp. sensors (3,4) one of which monitors the temp. of the water contained in the tank (9) and the other positioned in close proximity to the electric heating element (1). Each sensor (3,4) comprises a temp.-dependant resistor, with their outputs fed to a comparator (10) for providing an output signal indicating calcification when the difference between the outputs exceeds a given level. The indicator can also be used for a through-flow electric water heater in which case the two sensors (3,4) are spaced along the flow direction, one attached to the wall of the flow pipe contacted by the heating element, the other attached to the opposite wall of the flow pipe.</p> |
