Portable fire detection system

Claim 1

A portable fire detection and alarm system including a power supply and monitor unit, said detection and alarm system comprising: a plurality of ionization type smoke detectors having a pair of power input terminals, and a pair of alarm output terminals that are electrically interconnected by the detection of smoke, each pair of input and output terminals being connected to respective pair of conductors having first and second ends, each ends of said respective pair of conductors being coupled to the power supply and monitor unit; the power supply and monitor unit including: a power supply providing a first DC power source provided by rectified AC input power and a second DC power source derived from batteries rechargeable from said first power source, said first and second sources having a common ground; first circuitry coupling said second DC. power source and said common ground to the first ends of said pair of smoke detector power input lead conductors; second circuitry coupling the first end of a first one of said pair of smoke detector alarm output conductors to said common ground and the first end of a second one of said pair of smoke detector alarm output conductors to one end of the excitation coil of an alarm relay, the second end of the excitation coil of said alarm relay being coupled to said second DC source; a telephone auto-dialer and message transmitter coupled to the relay contacts of said alarm relay and responsive to the energizing of said alarm relay for transmitting a prerecorded alarm message to a predetermined telephone number; a first supervisory relay having a coil coupled to the second ends of said pair of said smoke detector power input conductors, the contacts of said relay normally connecting a supervisory conductor to common ground, the excitation of said first supervisory relay coil removing said supervisory conductor from said ground; second and third supervisory relays each having a first coil end coupled to the second ends of said pair of smoke detector alarm output conductors and a second coil end coupled to said first DC power source, the contacts of said second and third supervisory relays normally connecting said supervisory conductor to common ground; and a trouble signaling relay having its coil coupled between said second DC source and said supervisory conductor, said trouble signaling relay being energized by a loss of AC input power and absence of continuity through the smoke detector power input and output alarm circuit conductors, and said telephone auto-dialer and message transmitter coupled to the contacts of said trouble signaling relay and responsive to the energizing of said trouble signaling relay for transmitting a prerecorded trouble message to a predetermined telephone number.