Safety device for domestic water supply - detects leak or open tap by uniformity of flow to operate shut-down valve

摘要

The device limits the time for which water is allowed to escape through a pipe leak or a tap which has been left open, by using a switch responsive to the water flow to operate a timer with the shut-down valve closed automatically is the flow remains the same throughout the timer interval. The variations in the flow are detected by two sensors (7,8) comprising temp. dependent resistors positioned one behind the other in the water line (4,5) and connected to a measuring bridge (12). The upstream sensor (7) is warmed by an incorporated heating element and the temp. difference between the sensors is used to actuate the timer (18) via a relay coupled to the output of the bridge, the magnetic shut-down valve (28) operated automatically at the end of the timer duration with the timer (18) being automatically reset. The device is used for dwellings etc. left empty for long periods.