Fire detector
First Claim
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1. A heat-photoelectric type fire detector comprising:
- a light-emitting section for emitting a pulsed light for detecting smoke;
a light-receiving section, having a first variable resistor for adjusting an output, for receiving a scattering light of the light emitted from said light-emitting section caused by the smoke;
a smoke fire discriminating section, having a second variable resistor for adjusting a reference voltage, for generating a smoke fire discriminating output when the output from said light-receiving section reaches the reference voltage;
a heat-sensitive element for detecting heat;
a heat fire discriminating section for outputting a heat fire discriminating output when a detected output from said heat-sensitive element reaches a predetermined level; and
a fire signal transmitting section, having an operation indicating lamp, for outputting a fire signal when a smoke fire discriminating output or a heat fire discriminating output is generated from at least one of said smoke fire discriminating section and said heat fire discriminating section;
wherein said light-emitting section comprises a light-emitting element for detecting smoke, an oscillating circuit for making said light-emitting section emit light by supplying a pulsed output thereto and supplying the pulsed output as a monitoring power source to said heat fire discriminating section, and a pulse width expanding circuit for expanding a pulse width of the pulsed output from said oscillating circuit and supplying it to said operation indicating lamp.
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Abstract
A fire detector capable of readily and accurately adjusting the sensitivity thereof and of not erroneously outputting any fire signal is provided with a first-stage amplifying circuit having an output adjusting variable resistor and a fire discriminating section having a reference voltage adjusting variable resistor. As a result, it is possible to adjust the amplified output to a predetermined value by the switching level of the fire discriminating section to a predetermined value by the reference voltage adjusting variable resistor.
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Citations
11 Claims
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1. A heat-photoelectric type fire detector comprising:
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a light-emitting section for emitting a pulsed light for detecting smoke; a light-receiving section, having a first variable resistor for adjusting an output, for receiving a scattering light of the light emitted from said light-emitting section caused by the smoke; a smoke fire discriminating section, having a second variable resistor for adjusting a reference voltage, for generating a smoke fire discriminating output when the output from said light-receiving section reaches the reference voltage; a heat-sensitive element for detecting heat; a heat fire discriminating section for outputting a heat fire discriminating output when a detected output from said heat-sensitive element reaches a predetermined level; and a fire signal transmitting section, having an operation indicating lamp, for outputting a fire signal when a smoke fire discriminating output or a heat fire discriminating output is generated from at least one of said smoke fire discriminating section and said heat fire discriminating section; wherein said light-emitting section comprises a light-emitting element for detecting smoke, an oscillating circuit for making said light-emitting section emit light by supplying a pulsed output thereto and supplying the pulsed output as a monitoring power source to said heat fire discriminating section, and a pulse width expanding circuit for expanding a pulse width of the pulsed output from said oscillating circuit and supplying it to said operation indicating lamp. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A heat-photoelectric type fire detector comprising:
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a light-emitting section for emitting pulsed light for detecting smoke; a light-receiving section for receiving scattered light of the light emitted from said light-emitting section caused by smoke; a smoke fire discriminating section for providing a smoke fire discriminating output when a light-receiving output from said light-receiving section reaches a reference voltage; a heat-sensitive element for detecting heat; a heat fire discriminating section for providing a heat fire discriminating output when a detected output from said heat-sensitive element reaches a predetermined level; a fire signal transmitting section for transmitting a fire signal when a smoke fire discriminating output or a heat fire discriminating output is output from at least one of said smoke fire discriminating section and said heat fire discriminating section; and a constant voltage circuit for converting an externally supplied power source voltage into a predetermined voltage, and supplying it to said light-emitting section, said light-receiving section, said smoke fire discriminating section and said heat fire discriminating section; said constant voltage circuit comprising; a first transistor having an emitter connected to said light-emitting section, said light-receiving section, said smoke fire discriminating section and said heat fire discriminating section; a first Zener diode having an end connected to a base of said first transistor; and a constant current circuit connected between a collector and the base of said first transistor. - View Dependent Claims (8, 9, 10, 11)
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Specification