GB766518A - Improvements in or relating to an optical instrument for determining the density of smoke - Google Patents

Improvements in or relating to an optical instrument for determining the density of smoke

Info

Publication number
GB766518A
GB766518A GB7198/55A GB719855A GB766518A GB 766518 A GB766518 A GB 766518A GB 7198/55 A GB7198/55 A GB 7198/55A GB 719855 A GB719855 A GB 719855A GB 766518 A GB766518 A GB 766518A
Authority
GB
United Kingdom
Prior art keywords
disc
smoke
density
light
reflecting plate
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
GB7198/55A
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.)
MSA Safety Inc
Original Assignee
Mine Safety Appliances Co
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 Mine Safety Appliances Co filed Critical Mine Safety Appliances Co
Publication of GB766518A publication Critical patent/GB766518A/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
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/29—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands using visual detection

Landscapes

  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Telescopes (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

766,518. Turbidometers. MINE SAFETY APPLIANCE CO. March 11, 1955 [March 25, 1954], No. 7198/55. Class 97(3) In apparatus for determining the density of smoke by comparing it with a chart of standard densities, the smoke can be seen through only a central area of an inclined reflecting plate and is surrounded in the field of view by an image of translucent disc 13 having areas each of standard density. The disc is illuminated by light from only that portion of the sky in the vicinity of the smoke and lens 17 ensures that substantially paralled light is directed from the disc 13 on to the reflecting plate so that the disc is seen with the same ocular accommodation as is the smoke. The reflecting plate may be a mirror 31 having a clear central portion or it may be of clear glass 9 and shielded from incident light by diaphragm 11. Preferably light from the central part of disc 13 is prevented from reaching the eye either, by a hole in the inclined plate or, by an opaque circular disc 18. In the form shown in Fig. 5, a diffusing screen 39 is provided.
GB7198/55A 1954-03-25 1955-03-11 Improvements in or relating to an optical instrument for determining the density of smoke Expired GB766518A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US418542A US2921497A (en) 1954-03-25 1954-03-25 Optical instrument for smoke determination

Publications (1)

Publication Number Publication Date
GB766518A true GB766518A (en) 1957-01-23

Family

ID=23658560

Family Applications (1)

Application Number Title Priority Date Filing Date
GB7198/55A Expired GB766518A (en) 1954-03-25 1955-03-11 Improvements in or relating to an optical instrument for determining the density of smoke

Country Status (2)

Country Link
US (1) US2921497A (en)
GB (1) GB766518A (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3779650A (en) * 1971-06-25 1973-12-18 J Crowley Portable smoke measuring device
US3841763A (en) * 1973-06-25 1974-10-15 Timelapse Inc Method and apparatus for monitoring and correlating visible environmental contamination

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US683203A (en) * 1900-12-26 1901-09-24 Howard Grubb Sighting device for guns.
GB191121086A (en) * 1911-09-25 1912-07-18 John Rickards Middleton An Instrument for Estimating the Range and Direction of Motion of an Objective Ship for Which Pictures or Photographs in Various Attitudes are Available.
US1385940A (en) * 1920-01-14 1921-07-26 Valcoulon L Ellicott Method of and apparatus for determining photographic exposures
DE350236C (en) * 1921-01-14 1922-03-16 Wilhelm Schlichter Dr Light meters for photographic use
GB225690A (en) * 1923-11-08 1924-12-11 John Malyon Waldram Apparatus for photometric measurements and comparisons
US2154374A (en) * 1938-11-30 1939-04-11 George M Byram Haze meter
US2243383A (en) * 1939-01-10 1941-05-27 Leber Alois Photoelectric exposure meter
US2336239A (en) * 1939-08-28 1943-12-07 Barr & Stroud Ltd Optical sighting apparatus

Also Published As

Publication number Publication date
US2921497A (en) 1960-01-19

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