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 smokeInfo
- 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
Links
- 239000000779 smoke Substances 0.000 title abstract 5
- 230000003287 optical effect Effects 0.000 title 1
- 230000004308 accommodation Effects 0.000 abstract 1
- 239000011521 glass Substances 0.000 abstract 1
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.
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)
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)
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 |
-
1954
- 1954-03-25 US US418542A patent/US2921497A/en not_active Expired - Lifetime
-
1955
- 1955-03-11 GB GB7198/55A patent/GB766518A/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
US2921497A (en) | 1960-01-19 |
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