Accession Number : ADD008424

Title :   Processor-Aided Fire Detector.

Descriptive Note : Patent,


Personal Author(s) : Street,Thomas T ; Alexander,John I

Report Date : 03 Mar 1981

Pagination or Media Count : 11

Abstract : This abstract describes a fire detection system which includes an environmental sampling assembly coupled to a programmable digital processor for detecting a threat of fire and reducing the occurrences of false alarms in a changing environment. The sampling assembly comprises a network of air ducts, a chamber, two sensors, and an exhaust fan. The processor includes two analog-to-digital (A/D) converters, a multiplexed digital summer, short and long-term storage mediums, a signal magnitude comparator, logic circuitry, and a timing generator. The fan continuously draws ambient air through the air ducts and the chamber. Sensors within the chamber sample the air. If the sensors detect particulates of combustion in the air, the sensors provide electrical signals of varying amplitudes, which amplitudes being sampled, to the A/D converters of the processor. One of the sensors also feeds its signals to the fan motor for increasing the speed of the fan, thereby clearing the chamber and drawing air through the chamber at a faster rate for a more vigorous sampling of the environment. The processor may be programmed to suit a specific environment. It monitors the amplitudes of the signals from the assembly and the rate and duration of changes in the amplitudes by comparing signal samples at successive intervals of time. The processor activates a four-level, visual alarm which indicates the progression or regression of a threat of fire.

Descriptors :   *Patents, *Fire detectors, *Computer applications, *Signal processing, Inventions, Logic circuits, Analog to digital converters, Air, Sampling, Multiplexing, Digital systems, Memory devices, Particulates, Computer programming, Schematic diagrams

Subject Categories : Computer Programming and Software
      Computer Hardware
      Safety Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE