US 4,088,986 AGranted

Smoke, fire and gas alarm with remote sensing, back-up emergency power, and system self monitoring

OwnerCharles E. Boucherinventor

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Abstract

A system for sensing smoke and fire, primarily through the sensing of associated carbon monoixide and optionally with supplementary heat sensing, and for sensing hazardous gases and vapors. The system senses the presence of carbon monoxide, even in the absence of fire and is capable of sensing the presence of hydrogen and hydrocarbon vapors such as methane and propane. Additionally, the volatile vapors of paints, varnishes and other household and industrial substances are detectable. The system also includes circuitry and equipment for notification and warning of such detection, together with circuitry and equipment for providing emergency operation in the event of normal power failure. Further circuitry and equipment for self-monitoring of system remote wiring and sensor integrity, and associated notification means for such integrity checks is included. The system provides for the use of a suitable multitude of sensor devices located remotely from a main control unit, so that sensor device locations may be chosen to maximize the possibility of detecting the presence of smoke, fire or the gases and vapors previously described. The system also includes a novel form of sounding device, of the type wherein an electro-magnet causes a hammer to strike a sounding apparatus with such sounding devices being suitable for use in flammable, combustible or otherwise reactive atmospheres.

Claims16

Dependent claims

A smoke, fire and gas alarm characterized by a plurality of remote sensors and a central control and alarm unit, comprising:

A. a plurality of remote gas sensing means which respond to the presence of carbon monoxide and the like by a lowered electrical resistance;
and
B. a centralized power supply operable for generating a D.C. supply voltage to each of said remote sensors, and for generating further distinct voltage levels VL1 and VL2, said power supply being characterized by a normal supply source and an alternate supply source, and including automatic means to switch therebetween;
and
C. centralized threshold circuits for each of said remote sensors, each threshold circuit being adapted to compare said voltage level VL2 with a voltage from its associated sensor to produce a sensor output voltage;
and
D. a centralized processing unit for receiving a sensor output voltage from each of said threshold circuits, said processing unit comprising logic element means for comparing each of said plurality of sensor output voltages with said voltage levels VL1 and VL2, said logic means further being adapted for generating an enabling processing unit output signal in response to either increase or a decrease of any of said sensor output voltages;
and
E. a centralized alarm power drive for receiving said processing unit output signal, said alarm drive comprising a oscillator for generating a variable alarm signal;
and
F. a centralized alarm, responsive to said alarm signal, and further comprising an interruptor device having means to prevent ignition of an explosive gas in the vicinity of said alarm.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 05/728,813Filed 1 Oct 1976
Granted: 9 May 1978
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G08B 29/181
Prevention or correction of operating errors: due to failing power supply
G08B 17/06
Fire alarms; Alarms responsive to explosion: electric actuation of the alarm, e.g. using a thermally-operated switch
G08B 17/117
Actuation by presence of smoke or gases , e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means: by using…
G08B 29/043
Monitoring of the detection circuits: of fire detection circuits