GB630490A - Improvements relating to light sensitive apparatus - Google Patents

Improvements relating to light sensitive apparatus

Info

Publication number
GB630490A
GB630490A GB18603/46A GB1860346A GB630490A GB 630490 A GB630490 A GB 630490A GB 18603/46 A GB18603/46 A GB 18603/46A GB 1860346 A GB1860346 A GB 1860346A GB 630490 A GB630490 A GB 630490A
Authority
GB
United Kingdom
Prior art keywords
smoke
frequencies
light
beams
photo
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
GB18603/46A
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.)
PERCIVAL EDWARD MCIVER
Original Assignee
PERCIVAL EDWARD MCIVER
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 PERCIVAL EDWARD MCIVER filed Critical PERCIVAL EDWARD MCIVER
Publication of GB630490A publication Critical patent/GB630490A/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
    • 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

Landscapes

  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Fire-Detection Mechanisms (AREA)

Abstract

630,490. Photo-electric smoke detection. McIVER, P. E. June 20, 1946, No. 18603. Convention date, July 16, 1945. [Class 40 (iii)] To compensate for undesired variations in source brightness in apparatus in which a beam of light is modulated by the presence of smoke, two beams of light C and E from a common source A fall on one photocell D. The two beams are " chopped " at different frequencies by " choppers " F and F<1>. Beam C falls direct on the cell and is shielded from outside influences. Beam E is interfered with by the smoke and then reflected back. The output of the photo-cell due to these two differing frequencies is amplified at H and split into two frequencies in filters I and I<1> and applied to indicating devices J, J<1>.
GB18603/46A 1945-07-16 1946-06-20 Improvements relating to light sensitive apparatus Expired GB630490A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NZ630490X 1945-07-16

Publications (1)

Publication Number Publication Date
GB630490A true GB630490A (en) 1949-10-14

Family

ID=19916000

Family Applications (1)

Application Number Title Priority Date Filing Date
GB18603/46A Expired GB630490A (en) 1945-07-16 1946-06-20 Improvements relating to light sensitive apparatus

Country Status (1)

Country Link
GB (1) GB630490A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2907889A (en) * 1955-09-23 1959-10-06 Nat Res Dev Fog detecting and visibility measuring systems

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2907889A (en) * 1955-09-23 1959-10-06 Nat Res Dev Fog detecting and visibility measuring systems

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