Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
321 words
A fire sensing system comprising: a fire sensor having a pair of load terminals and a pair of output terminals, said fire sensor being so constructed as to detect a predetermined combustion quantity relying upon a voltage applied to said load terminals and to produce a signal from said output terminals; a first d-c power supply and a second d-c power supply which are coupled in parallel with said pair of load terminals of said fire sensor; a first diode coupled between said first d-c power supply and said load terminals of said fire sensor and a second diode coupled between said second d-c power supply and said load terminals of said fire sensor such that the voltage of said first and second d-c power supplies are fed independently to said load terminals of said fire sensor; a first signal circuit consisting of a first semiconductor switching element which is connected between an anode terminal and a cathode terminal of said first d-c power supply, and having a trigger terminal which is coupled to said output terminals of said fire sensor; a second signal circuit consisting of a second semiconductor switching element which is connected between an anode terminal and a cathode terminal of said second d-c power supply, and having a trigger terminal which is coupled to said output terminals of said fire sensor; a first delay means provided between the trigger terminal of said first signal circuit and said output terminals of said fire sensor to delay the trigger signals; and a second delay circuit provided between the trigger terminal of said second signal circuit and said output terminals of said fire sensor to delay the trigger signals by a time which is longer than the delay time of said first delay means; whereby external noise energy causes said first signal circuit to operate, while said second signal circuit is stably maintained without being affected by the external noise.
Claim 2
Dependent Claim
321 words
A fire sensing system comprising: a fire sensor having a pair of load terminals and a pair of output terminals, said fire sensor being so constructed as to detect a predetermined combustion quantity relying upon a voltage applied to said load terminals and to produce a signal from said output terminals; a first d-c power supply and a second d-c power supply which are coupled in parallel with said pair of load terminals of said fire sensor; a first diode coupled between said first d-c power supply and said load terminals of said fire sensor and a second diode coupled between said second d-c power supply and said load terminals of said fire sensor such that the voltage of said first and second d-c power supplies are fed independently to said load terminals of said fire sensor; a first signal circuit consisting of a first semiconductor switching element which is connected between an anode terminal and a cathode terminal of said first d-c power supply, and having a trigger terminal which is coupled to said output terminals of said fire sensor; a second signal circuit consisting of a second semiconductor switching element which is connected between an anode terminal and a cathode terminal of said second d-c power supply, and having a trigger terminal which is coupled to said output terminals of said fire sensor; a first delay means provided between the trigger terminal of said first signal circuit and said output terminals of said fire sensor to delay the trigger signals; and a second delay circuit provided between the trigger terminal of said second signal circuit and said output terminals of said fire sensor to delay the trigger signals by a time which is longer than the delay time of said first delay means; whereby external noise energy causes said first signal circuit to operate, while said second signal circuit is stably maintained without being affected by the external noise.
Claim 3
Dependent Claim
141 words
A fire sensing system as recited in claim 1, which further comprises: a plurality of relays, a first relay of said plurality of relays being coupled between said first d-c power supply and said first semiconductor switching element, said first relay responding to an increased current signal which flows from said first d-c power supply when said first semiconductor switching element is rendered conductive, a second relay of said plurality of relays being coupled between said second d-c power supply and said second semiconductor switching element, said second relay responding to an increased current signal which flows from said second d-c power supply when said second semiconductor switching element is rendered conductive; and safety means selected from the group consisting of fire alarming means, fire preventing means, and fire extinguishing means, said safety means being operated by said plurality of relays.
Claim 4
Dependent Claim
118 words
A fire sensing system as recited in claim 1, which further comprises: variable sensitivity amplifier means coupled between said output terminals of said fire sensor and said trigger terminals of said first and second semiconductor switching elements, for supplying a first trigger signal to said trigger terminal of said first semiconductor switching element when a first signal having a first voltage level continuously appears at said output terminals for a first predetermined time period, and for supplying a second trigger signal to said trigger terminal of said second semiconductor switching element when, subsequent to said first trigger signal, a second signal having a second voltage level continuously appears at said output terminals for a second predetermined time period.