Ionization smoke detector co-used to issue fire alarm and detect ambient atmosphere
First Claim
1. A measuring apparatus co-using an ionization smoke detector operative to initiate a fire alarm and to detect the ambient atmosphere, which comprises:
- a main circuit comprisinga line adapted to be connected to a power source including an ionization smoke detector having an outer ionization chamber and an inner ioniation chamber connected in series with an intermediate electrode,a field effect transistor connected to said line in parallel to the ionization smoke detector for control by the relative potential of said intermediate electrode located between said two chambers, andan alarm device connected to the power line in parallel to both the field effect transistor and the ionization smoke detector, a relay connected in the power line to operate said alarm device when said relay is energized by an increase of current conducted from said field effect transistor in response to potential change in said electrode and an auxiliary circuit comprisinga second field effect transistor controlled by the relative potential of said intermediate electrode,a second power line associated with said second transistor,a visual indicating device connected to said second power line in parallel to said second transistor by which potential change at the intermediate electrode is converted to change of a current in said second power line and to display the change at the visual indicating device.
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Accused Products
Abstract
A fire alarm system having a plurality of ceiling fixtures containing ionization smoke detectors which are located in regions of a building to be protected. Each smoke detector is connected to a common fire alarm signal receiver for sounding an audible alarm as well as a visual alarm in response to a fire alarm signal therefrom. Each ionization smoke detector is also provided with an ionization ambient atmosphere auxiliary co-detector for producing an auxiliary signal which is responsive to the environmental conditions of the detector in situ. The ambient atmosphere detector comprises an internal circuit having female terminals of a receptacle mounted in the wall of the corresponding fixture, and an external circuit having male terminals of a plug adapted to mate with the corresponding female terminals of such receptacle. Such external circuit contains a visual signal indicating device as well as a recorder for tracing auxiliary signal patterns on a tape synchronized with the actual time of test of the ionization smoke detector being checked. Such patterns provide characteristic shapes corresponding to stable air, strong air current, feeble air current, dust, steam, static discharge, and cooking combustion products of the ambient atmosphere as distinguished from smoke due to fire, while the fire detector system per se is in actual use, and subject to possible false alarm caused by environmental conditions other than fire.
15 Citations
17 Claims
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1. A measuring apparatus co-using an ionization smoke detector operative to initiate a fire alarm and to detect the ambient atmosphere, which comprises:
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a main circuit comprising a line adapted to be connected to a power source including an ionization smoke detector having an outer ionization chamber and an inner ioniation chamber connected in series with an intermediate electrode, a field effect transistor connected to said line in parallel to the ionization smoke detector for control by the relative potential of said intermediate electrode located between said two chambers, and an alarm device connected to the power line in parallel to both the field effect transistor and the ionization smoke detector, a relay connected in the power line to operate said alarm device when said relay is energized by an increase of current conducted from said field effect transistor in response to potential change in said electrode and an auxiliary circuit comprising a second field effect transistor controlled by the relative potential of said intermediate electrode, a second power line associated with said second transistor, a visual indicating device connected to said second power line in parallel to said second transistor by which potential change at the intermediate electrode is converted to change of a current in said second power line and to display the change at the visual indicating device.
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2. A fire alarm system comprising
an ionization detector having inner and outer chambers provided with individual electrodes and a common intermediate electrode; -
a remote fire alarm signal receiver circuit having an alarm activated when said detector responds to smoke therein; and an auxiliary circuit for testing the actual operation of said smoke detector in situ for possible false alarms, comprising an auxiliary signal generating circuit responsive to a potential between said common electrode and inner chamber electrode, having an output signal the strength of which varies with the condition of the ambient atmosphere, and a signal measuring circuit connected to said signal output circuit having a meter for indicating the relative strength of such output signal. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10)
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11. A fire alarm system comprising
a plurality of ionization smoke detectors provided with ceiling fixtures distributed in different regions of possible fire, said fixture including in each a wall receptacle having female terminals across which is a potential that corresponds to an ionization potential between electrodes of each detector, a case incorporated in said fixture, having inner and outer chambers provided with a common intermediate electrode and individual electrodes, a fire alarm originating circuit signal connected across said individual inner and outer chamber electrodes, and an auxiliary signal originating circuit connected across said intermediate electrode and outer chamber electrode for amplifying and applying said potential to said female terminals, and an auxiliary ionization signal indicating circuit having a plug having male terminals adapted to be plugged into the receptacle of any selected one of said wall fixtures for checking in situ a selected ionization smoke detector for auxiliary signals corresponding to possible false alarm signals.
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15. A dual smoke ionization fire detector and ambient atmosphere ionization monitoring apparatus comprising
an ionization smoke detector having electrodes between which potential varies with ambient atmosphere ionization while said ionization smoke detector is on duty and subject to false alarm when no fire exists, auxiliary circuit means for amplifying and producing an auxiliary output signal that is proportional to said variable potential due to ambient atmosphere conditions which might cause said ionization smoke detector to issue a false alarm signal, and indicating circuit means for measuring and continuously recording such auxiliary output signal while the fire detector is on duty.
Specification