Fluid leakage detector for intermittently used supplies - uses metal ball in flow and proximity detector circuit to initiate timing of flow duration against preset max. time

摘要

Flow detection is on a yes-no basis rather than proportional to flow rate and the time duration of the flow is measured against a pre-set max. time to activate an alarm and/or automatic turn off of the water supply if the preset time is exceeded. The flow detector comprises a metal ball (7) placed in the fluid path so it is readily lifted off its no-flow seat (8) to a grille (9) limiting the upward travel. An electronic metal detector circuit (10) senses the rising of the metal ball through the wall (5a) of the flow chamber. The signal from the detector is fed (11) to a circuit which triggers an astable multivibrator (2) whose output pulses are counted in a pre-set counter circuit (2) which gives a signal when the pre-set count is reached. This signal may operate an alarm or switch a motor (13) driven ON-OFF valve (18).