GB1278205A - Smoke detecting device - Google Patents

Smoke detecting device

Info

Publication number
GB1278205A
GB1278205A GB6619/70A GB661970A GB1278205A GB 1278205 A GB1278205 A GB 1278205A GB 6619/70 A GB6619/70 A GB 6619/70A GB 661970 A GB661970 A GB 661970A GB 1278205 A GB1278205 A GB 1278205A
Authority
GB
United Kingdom
Prior art keywords
lamp
photo
cell
smoke
detector
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.)
Expired
Application number
GB6619/70A
Inventor
Norman Ian Buckley
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.)
Shorrock Developments Ltd
Original Assignee
Shorrock Developments 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 Shorrock Developments Ltd filed Critical Shorrock Developments Ltd
Priority to GB6619/70A priority Critical patent/GB1278205A/en
Priority to DE19712105917 priority patent/DE2105917A1/en
Priority to ZA710788A priority patent/ZA71788B/en
Publication of GB1278205A publication Critical patent/GB1278205A/en
Expired 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
    • 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
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/255—Details, e.g. use of specially adapted sources, lighting or optical systems
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B17/00—Fire alarms; Alarms responsive to explosion
    • G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
    • G08B17/103—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using a light emitting and receiving device
    • G08B17/107—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using a light emitting and receiving device for detecting light-scattering due to smoke
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B17/00—Fire alarms; Alarms responsive to explosion
    • G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
    • G08B17/11—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using an ionisation chamber for detecting smoke or gas
    • G08B17/113—Constructional details

Abstract

1278205 Smoke detector SHORROCK DEVELOPMENTS Ltd 19 April 1971 [11 Feb 1970] 6619/70 Heading G1A A smoke detector comprises a lamp Q 1 radiating a beam of visible or infrared light across a space in which the presence of smoke is to be detected, a photo-cell P 1 located to receive light diffused by the smoke but not light direct from the beam, an oscillator 1 flashing the lamp Q on and off at a predetermined rate, and a phase detector 5 connected to receive signals both from the oscillator 1 and from the photo-cell P1 the phase detector operating an alarm when both signals are present and in phase. In an embodiment, Fig.1, the output of the phase detector is fed to an integrating circuit 6, which has a variable time constant that is set so as to suppress background or false signals. The output of the integrator is connected to a power amplifier 7 which switches on a lamp Q 2 when a smoke alarm signal is received for a time greater than the selected period of the integrator 6. In order to ensure that an alarm is given if the lamp Q 1 breaks, or, to compensate for any diminution of its light input, a second photo-cell P 2 is placed directly in the path of the beam. The output of the photo-cell P 2 is taken to an amplifier detector 8 which switches on a lamp Q 3 if the pulses are discontinued, or if the intensity of illumination falls below a predetermined value. Any decreasing output of lamp Q 1 is compensated by taking the decreasing amplifier detector output to a variable feedback signal generator 9 which applies its decreasing output to the power amplifier 7 and thus increases the gain of the power amplifier 7 and thereby maintains the overall sensitivity of the smoke detector. The smoke detector can be tested to see if it is functioning correctly by including an extra lamp in series with Q 1 but which is normally short circuited. The extra lamp being located so as to illuminate the photo-cell P 1 . A manually operated test button is provided so as to switch on this test lamp, and thus, on receipt by the photo-cell of signals due to the test lamp, the alarm Q 2 is operated.
GB6619/70A 1970-02-11 1970-02-11 Smoke detecting device Expired GB1278205A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
GB6619/70A GB1278205A (en) 1970-02-11 1970-02-11 Smoke detecting device
DE19712105917 DE2105917A1 (en) 1970-02-11 1971-02-09 Smoke indicator
ZA710788A ZA71788B (en) 1970-02-11 1971-02-09 Smoke detecting device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB6619/70A GB1278205A (en) 1970-02-11 1970-02-11 Smoke detecting device

Publications (1)

Publication Number Publication Date
GB1278205A true GB1278205A (en) 1972-06-21

Family

ID=9817774

Family Applications (1)

Application Number Title Priority Date Filing Date
GB6619/70A Expired GB1278205A (en) 1970-02-11 1970-02-11 Smoke detecting device

Country Status (3)

Country Link
DE (1) DE2105917A1 (en)
GB (1) GB1278205A (en)
ZA (1) ZA71788B (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU577551B2 (en) * 1983-10-21 1988-09-29 Vision Systems Limited Improvements relating to smoke detection apparatus
WO2009103619A1 (en) * 2008-02-21 2009-08-27 Endress+Hauser Conducta Gesellschaft Für Mess- Und Regeltechnik Mbh+Co. Kg Method and optical sensor arrangement for detecting a measured variable of a medium, in particular for turbidity measurement

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1405615A (en) * 1972-08-11 1975-09-10 Chubb Fire Security Ltd Fire alarms
IL45331A (en) * 1973-11-26 1977-12-30 Chloride Batterijen Bv Photoelectric smoke detector
AU497359B2 (en) * 1974-11-27 1978-12-07 Pyrotector, Incorporated Photoelectric smoke detector
JPS5631625A (en) * 1979-08-24 1981-03-31 Hochiki Corp Smoke detector of photoelectronic type
EP0145189B1 (en) * 1983-10-21 1990-08-08 COLE, Martin Terence Improvements relating to smoke detection apparatus

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU577551B2 (en) * 1983-10-21 1988-09-29 Vision Systems Limited Improvements relating to smoke detection apparatus
WO2009103619A1 (en) * 2008-02-21 2009-08-27 Endress+Hauser Conducta Gesellschaft Für Mess- Und Regeltechnik Mbh+Co. Kg Method and optical sensor arrangement for detecting a measured variable of a medium, in particular for turbidity measurement

Also Published As

Publication number Publication date
DE2105917A1 (en) 1971-08-26
ZA71788B (en) 1971-11-24

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Legal Events

Date Code Title Description
PS Patent sealed
PLNP Patent lapsed through nonpayment of renewal fees