Abstract: A fluid drip detection system which is not prone to false alarms caused by the presence of dirt or solid particle contaminants in the fluid. The fluid drip detector comprises; a conducting hollow housing for permitting fluid flow and passage therethrough, the housing having a first and second conducting seats. A first conducting door is urged against the first seat and a second conducting door is urged against the second seat. The first and second doors disengage from their respective seats in a drip condition and in response to fluid movement. A conducting rod is connected to one of the doors and is slidingly fitted into a bore in the other door, such that in a no drip condition, if one of the doors is disengaged from its seat by dirt, the other door can still engage its seat, and a lead connected to the housing, for producing an electrical output in the event of a drip. Such electrical output is transmitted to a timer unit that can control the fluid flow by controlling a cut off valve.

Abstract: An electric resistance measuring device situated in fluids, comprising; a housing having a bore therethrough, the bore having a seat; a movable door means situated in the bore, engagable with the seat; whereby, fluid movement disengages the door from the seat, changing the electrical resistance between the seat and the door. Such a device can detect leaks which increase the electrical resistance between the seat and the door. A panel provides selector means which can be set at different modes, each mode providing a different period of time in which fluid can be used continuously without interruption. If fluid movement exists after such period, a cut off valve will shut off the fluid. Such a device can be installed in line with fire sprinklers, such that the device will detect a fire and will send a signal to a central station.