Fluid flow detector for a fire alarm system

Abstract From the Canadian patent

A sprinkler flow detector is described which can detect and rapidly respond to the onset of water flow in a sprinkler system which results, for example from the release, of one or more sprinklers The detector senses the pressure, vs. time profile of the system or house side of the sprinkler system. An increase in pressure is accurately tracked without causing alarm. If, however, the pressure falls in excess of certain predetermined rates and amounts and holds in the lower, state for in excess of a second certain predetermined amount of time, the detector enters an alarm state. In a preferred embodiment the detector features a trouble state in which it responds to one of several monitored …