GB852325A - Improved means responsive to the density of smoke - Google Patents

Improved means responsive to the density of smoke

Info

Publication number
GB852325A
GB852325A GB7174/56A GB717456A GB852325A GB 852325 A GB852325 A GB 852325A GB 7174/56 A GB7174/56 A GB 7174/56A GB 717456 A GB717456 A GB 717456A GB 852325 A GB852325 A GB 852325A
Authority
GB
United Kingdom
Prior art keywords
smoke
light
voltage
cell
potentiometer
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
GB7174/56A
Inventor
Robert Trevor Craxton
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.)
British Thomson Houston Co Ltd
Original Assignee
British Thomson Houston Co 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 British Thomson Houston Co Ltd filed Critical British Thomson Houston Co Ltd
Priority to GB7174/56A priority Critical patent/GB852325A/en
Publication of GB852325A publication Critical patent/GB852325A/en
Expired legal-status Critical Current

Links

Classifications

    • 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
    • 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
    • G01N21/534—Scattering, i.e. diffuse reflection within a body or fluid within a flowing fluid, e.g. smoke by measuring transmission alone, i.e. determining opacity
    • 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

Landscapes

  • Analytical Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Biochemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

852,325. Photo-electric smoke detection. BRITISH THOMSON-HOUSTON CO. Ltd. March 6, 1957 [March 7, 1956], No. 7174/56. Class 40(3). [Also in Group XXXV] In a smoke detection apparatus light from a source 5 is projected across a smoke duct 1 on to two concentrically arranged photo-electric cells 6, 7, the annular cell 7 receiving light attenuated by smoke in the duct 1 while the inner cell 6 receives unattenuated light via a smoke proof tube 4 in the centre of the beam. The signal from the unattenuated beam is represented at V1 and the signal of the attenuated beam at V2. The voltage between the moving contact of a potentiometer 11 and one of its ends is compared at 12 with the voltage V2 and the resultant signal fed to a servo-unit 13 which rotates the arm of the potentiometer 11 to reduce the difference to zero. The voltage V1 is compared with a constant reference source and the difference used to control the brightness of the light 5 in compensation for smoke deposit on the cell and light windows 9, 8. An alarm is energized when a maximum voltage is attained.
GB7174/56A 1956-03-07 1956-03-07 Improved means responsive to the density of smoke Expired GB852325A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB7174/56A GB852325A (en) 1956-03-07 1956-03-07 Improved means responsive to the density of smoke

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB7174/56A GB852325A (en) 1956-03-07 1956-03-07 Improved means responsive to the density of smoke

Publications (1)

Publication Number Publication Date
GB852325A true GB852325A (en) 1960-10-26

Family

ID=9828036

Family Applications (1)

Application Number Title Priority Date Filing Date
GB7174/56A Expired GB852325A (en) 1956-03-07 1956-03-07 Improved means responsive to the density of smoke

Country Status (1)

Country Link
GB (1) GB852325A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0047049A1 (en) * 1980-08-28 1982-03-10 The Babcock & Wilcox Company Opacity monitoring apparatus
GB2188725A (en) * 1986-03-18 1987-10-07 Hochiki Co Detecting system and detector

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0047049A1 (en) * 1980-08-28 1982-03-10 The Babcock & Wilcox Company Opacity monitoring apparatus
GB2188725A (en) * 1986-03-18 1987-10-07 Hochiki Co Detecting system and detector
GB2188725B (en) * 1986-03-18 1990-02-28 Hochiki Co Detecting system and detector

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