JPS57118142A - Scattering type smoke sensor - Google Patents

Scattering type smoke sensor

Info

Publication number
JPS57118142A
JPS57118142A JP417381A JP417381A JPS57118142A JP S57118142 A JPS57118142 A JP S57118142A JP 417381 A JP417381 A JP 417381A JP 417381 A JP417381 A JP 417381A JP S57118142 A JPS57118142 A JP S57118142A
Authority
JP
Japan
Prior art keywords
circuit
gains
amplifying
smoke
output
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP417381A
Other languages
Japanese (ja)
Inventor
Yoshihiko Okuda
Tsunehiko Araki
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Electric Works Co Ltd
Original Assignee
Matsushita Electric Works Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Matsushita Electric Works Ltd filed Critical Matsushita Electric Works Ltd
Priority to JP417381A priority Critical patent/JPS57118142A/en
Publication of JPS57118142A publication Critical patent/JPS57118142A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/47—Scattering, i.e. diffuse reflection
    • G01N21/49—Scattering, i.e. diffuse reflection within a body or fluid
    • G01N21/53—Scattering, i.e. diffuse reflection within a body or fluid within a flowing fluid, e.g. smoke

Abstract

PURPOSE:To perceive smoke with constant sensitivity irrespectively of distance, by increasing gains of an amplifying circuit amplifying a photodetecting signal from the light emitting time of a luminous element and making the gains zero before a reflected light from the surface of a wall is reached. CONSTITUTION:Light emitted from a luminous element 2 subjected to the pulse driving by a pulse oscillation circuit 1 is reflected by the particles of smoke 3 and its scattered light is made incident to a photodetector 4. An amplifying circuit 5 amplifying a photodetecting signal is connected to the side of output of the photodetector 4 and an amplifying circuit 6 constituted so as to vary gains periodically is connected to the side of its output. The gains start to rise by receiving the signal of the circuit 1 and is made zero before the light emitted from the element 2 is reflected from the side of a wall and is reached the element 4. The output of the circuit 6 is added to a threshold circuit 7 and moreover, is connected to an alarm circuit 8. The smoke can be perceived with constant sensitivity irrespectively of distance by varying the gains periodically in such a manner.
JP417381A 1981-01-14 1981-01-14 Scattering type smoke sensor Pending JPS57118142A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP417381A JPS57118142A (en) 1981-01-14 1981-01-14 Scattering type smoke sensor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP417381A JPS57118142A (en) 1981-01-14 1981-01-14 Scattering type smoke sensor

Publications (1)

Publication Number Publication Date
JPS57118142A true JPS57118142A (en) 1982-07-22

Family

ID=11577324

Family Applications (1)

Application Number Title Priority Date Filing Date
JP417381A Pending JPS57118142A (en) 1981-01-14 1981-01-14 Scattering type smoke sensor

Country Status (1)

Country Link
JP (1) JPS57118142A (en)

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