Fire detection and extinguishment system

• US 5,486,811 A
• Filed: 02/09/1994
• Issued: 01/23/1996
• Est. Priority Date: 02/09/1994
• Status: Expired due to Fees

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Dahl, Ernest A., Lugar, James R., Wehrle, John P.
• Primary Examiner(s): Crosland, Donnie L.
• Application Number:
  US08/193,984
• Time in Patent Office: 713 Days
• Field of Search: 340/511, 340/517, 340/521, 340/518, 340/628, 340/578, 340/629, 340/522, 340/825.06, 169/60, 169/61, 169/23
• US Class Current: 340/522
• CPC Class Codes: A62C 3/10 in ships A62C3/0207 takes precedence
• CPC Class Codes: G08B 17/00 Fire alarms; Alarms responsive to explosion
• CPC Class Codes: G08B 17/113 Constructional details
• CPC Class Codes: G08B 17/117 by using a detection device for specific gases, e.g. combustion products, produced by the fire G08B17/103, G08B17/11 take precedence
• CPC Class Codes: G08B 29/183 Single detectors using dual technologies G08B13/1672, G08B13/2448, G08B13/2494 take precedence

Abstract

Early fire detection and extinguishment is provided by a plurality of fireetection units, each associated with a localized portion of a protected space and including condition sensors specifically appropriate to the environment of that localized portion of a protected space by a selected combination of condition sensors. A fire alarm annunciator and at least one controlled fire extinguishment system portion, or a stand-alone fire extinguishment system, is provided for each fire detection unit. A central control unit preferably includes a profile detector which evaluates outputs of one or more condition sensors over time to reduce false alarm rates while increasing sensitivity to early stage fires.

Claims

1. A fire detection and extinguishment system for detecting and extinguishing early stage fires in a protected space, comprising:

at least one fire detector unit including at least a carbon monoxide sensor and a radiation sensitive flame detector, said at least one fire detector unit associated with a localized portion of a protected space;

a central control unit including at least a sampler for periodically receiving data measured by at least said carbon monoxide sensor and said radiation sensitive flame detector, a memory for storing said received data and a profile detector responsive to said stored data, said memory storing therein said received data in the form of time profiles of variations of said data measured over a period of time by at least said carbon monoxide sensor and said radiation sensitive flame detector, said memory further having stored therein known data indicative of early stages of a fire, said known data corresponding to said data measured by at least said carbon monoxide sensor and said radiation sensitive flame detector, wherein said profile detector compares said measured data with said corresponding known data;

a communication system for communicating between said at least one fire detector unit and said central control unit; and

a controlled fire extinguishment system responsive to said central control unit, wherein said controlled fire extinguishment system includes at least one localized fine water mist supply and distribution system functioning to absorb heat produced by early stage fires, a central water supply for supplying pressurized water, at least one water supply main for transporting said pressurized water from said central water supply to said at least one localized fine water mist supply and distribution system, and at least one valve responsive to said central control unit for activating a flow of said pressurized water to said at least one localized fine water mist supply and distribution system, wherein said flow of pressurized water is supplied at a pressure of approximately 250 psi, said at least one localized fine water mist supply and distribution system responsive to one or more of said at least one fire detector unit and positioned within a localized portion of a protected space associated with said one or more of said at least one fire detector unit, and further said at least one localized fine water mist supply and distribution system including a plurality of distribution branches, a plurality of water mist nozzles mounted on each of said distribution branches, a supply riser and a distribution manifold for providing said pressurized water to said plurality of distribution branches, said nozzles being spaced at approximately 16 inch intervals on said distribution branches, said distribution branches being spaced at approximately four foot intervals along said distribution manifold, wherein said at least one fine water mist supply and distribution system provides a controlled distribution of fine water mist comprising water particles having diameters of about 100 microns at a water distribution density of about 0.05 gallons per minute for each square foot of protected area within said localized portion of a protected space associated with said at least one fire detector unit,

wherein upon said profile detector detecting a correlation between said measured data and said corresponding known data said central control unit activates said localized fine water mist supply and distribution system for providing said controlled distribution of fine water mist, said controlled distribution of fine water mist providing a large surface area of water particles for transferring heat out of early stage fires such that fire progression is halted.

2. A system as recited in claim 1, wherein said at least one fire detector unit further includes a humidity sensor, said sampler periodically receives data measured by said humidity sensor, said memory stores said received data in the form of a time profile of variations of said data measured over a period of time by said humidity sensor, and said profile detector is further responsive to said stored data measured by said humidity sensor.

3. A system as recited in claim 1, wherein said at least one fire detector unit further includes a temperature sensor, said sampler periodically receives data measured by said temperature sensor, said memory stores said received data in the form of a time profile of variations of said data measured over a period of time by said temperature sensor, and said profile detector is further responsive to said stored data measured by said temperature sensor.

4. A system as recited in claim 2, wherein said at least one fire detector unit further includes a temperature sensor, said sampler periodically receives data measured by said temperature sensor, said memory stores said received data in the form of a time profile of variations of said data measured over a period of time by said temperature sensor, and said profile detector is further responsive to said stored data measured by said temperature sensor.

5. A system as recited in claim 1, wherein said radiation sensitive flame detector comprises an infrared sensor.

6. A system as recited in claim 4, wherein said known data stored in said memory further corresponds to said data measured by said temperature sensor and said humidity sensor.

7. A system as recited in claim 5, wherein said infrared radiation sensor includes spectral filtering means.

8. A system as recited in claim 7, wherein said infrared radiation sensor includes flame flicker frequency filtering means.

9. A system as recited in claim 6, further including a sensor sensitive to combustion products produced by specified combustible material located within the protected space.