Apparatus and method for water flow fire alarm

A flow detecting means for use in a multipurpose residential fire suppression and water flow alarm system, the means comprising:

• a. an orifice plate disposed in the flow path between the supply and system side;
• b. a pair of sample ports, on the system side, the other on the supply side near the orifice plate;
• c. a differential pressure switch with two membranes, one in communication with the supply side, the other with the system side, the membranes being reactive to supply and system pressure and a magnet fixed between the membranes so that changes in pressure cause the membranes, thus the magnet to move;
• and
• d. a Reed switch adjacent to the magnet for providing an out put signal proportional to the position of the magnet.

A detecting means for use in a fire suppression and water flow alarm system, the means comprising:

• a. annular housing to be installed in the flow path of the system, the annular housing having a fixed interior diameter in at least one section;
• b. a moving orifice plate defining an opening therein where the orifice plate has a diameter which is smaller than the diameter of the fixed section of the annular housing, but is sized so as to allow minimal flow of water around its edges and between the diameter of the annular housing;
• c. a magnet adapted to abut the back face of the orifice plate facing an outlet from the annular housing;
• d. a biasing means for urging the moving orifice plate away from an outlet end of the annular housing;
• and
• e. at least one Reed switch disposed on an outer surface of the annular housing for creating an electronic signal related to the position of the orifice plate magnet within the annular housing, the Reed switch being attached so as to be easily movable in relation to and annular housing, whereby as fluid flows through the annular housing the orifice plate is urged towards to outlet end of the annular housing causing a change in the electronic signal created by the Reed switch.

An apparatus for use as a water flow fire alarm system comprising:

• a. a supply side for delivering a specified flow of water under pressure;
• b. a piping system for delivering water from the supply side to a fire suppression side with one or more sprinkler heads;
• c. a detecting means including two set points, the first set point for enunciating a warning alarm, the second set point for enunciating a fire alarm, the detecting means being disposed between the supply side and the system side;
• d. a drain test connection disposed between the detecting means and the system side for draining water from the system side and for simulating desired flow rates;
• and
• e. alarm means in communication with two detection means for enunciating first a warning alarm and next a fire alarm upon the detection of excessive flows.