US3775013A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical turbidimeter apparatus
Assignee: MONITEK TECHNOLOGIES Inc A DE CORP
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Filing: 1971-11-17
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Granted: 1973-11-27
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Expires: 1991-11-17
Abstract
Abstract An optical turbidimeter is provided with means for selectively changing the direction of propagation through a medium of one or more beams of radiation from a radiation source for measuring the turbidity in said medium utilizing forward light scattering or side light scattering. With the radiation beams in a first predetermined direction, unscattered radiation is detected by a first detector and the radiation scattered by the medium is detected by a second detector. With the radiation beams then redirected, the roles of the detectors are reversed and the first detector detects the scattered radiation and the second detector detects the unscattered radiation. An electronic circuit coupled to the detectors generates a pair of ratios corresponding to the amount of scattered and unscattered radiation received by the detectors for each position of the radiation beams for generating a signal the magnitude of which is independent of the color of the medium, source and detector drift and absorption and scattering at the source and detector windows. The circuitry also includes means for compensating for ambient radiation.
Inventors
- 👤 R Simms
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:40
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/47; G01N21/49; G01N21/53; G01N21/532
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
272 words
An optical turbidimeter comprising: a source of radiation for irradiating a medium the turbidity of which is proportional to the amount of said radiation scattered by said medium; a pair of detectors responsive to unscattered radiation from said source and radiation scattered by said medium; a passageway between said source and said detectors for receiving said medium; means for selectively directing said radiation through said medium for providing a first signal from a first one of said pair of detectors proportional to the amount of said radiation which is not scattered by said medium and a second signal from a second one of said detectors proportional to the amount of said radiation which is scattered by said medium; means for selectively redirecting said radiation through said medium for providing a third signal from said first one of said pair of detectors proportional to the amount of said radiation which is scattered by said medium and a fourth signal from said second one of said detectors proportional to the amount of said radiation which is not scattered by said medium; means coupled to said first and second detectors for selectively generating and storing a fifth signal proportional to the ratio of the magnitudes of said first and said second signals and a sixth signal proportional to the ratio of the magnitudes of said third and said fourth signals; and means coupled to said fifth and said sixth signal for generating and storing means for providing a seventh signal which is the root means square of the product of said fifth and said sixth signal and therefore proportional to the turbidity of said medium.
Claim 2
Dependent Claim
272 words
An optical turbidimeter comprising: a source of radiation for irradiating a medium the turbidity of which is proportional to the amount of said radiation scattered by said medium; a pair of detectors responsive to unscattered radiation from said source and radiation scattered by said medium; a passageway between said source and said detectors for receiving said medium; means for selectively directing said radiation through said medium for providing a first signal from a first one of said pair of detectors proportional to the amount of said radiation which is not scattered by said medium and a second signal from a second one of said detectors proportional to the amount of said radiation which is scattered by said medium; means for selectively redirecting said radiation through said medium for providing a third signal from said first one of said pair of detectors proportional to the amount of said radiation which is scattered by said medium and a fourth signal from said second one of said detectors proportional to the amount of said radiation which is not scattered by said medium; means coupled to said first and second detectors for selectively generating and storing a fifth signal proportional to the ratio of the magnitudes of said first and said second signals and a sixth signal proportional to the ratio of the magnitudes of said third and said fourth signals; and means coupled to said fifth and said sixth signal for generating and storing means for providing a seventh signal which is the root means square of the product of said fifth and said sixth signal and therefore proportional to the turbidity of said medium.
Claim 3
Dependent Claim
55 words
An optical turbidimeter according to claim 1 wherein said source of radiation comprises a first light source and a second light source and said means for selectively redirecting said radiation through said medium cOmprises means for selectively illuminating said first and said second light sources for generating sequentially said fifth and said sixth signal respectively.
Claim 4
Dependent Claim
77 words
An optical turbidimeter according to claim 2 wherein said first light source is positioned substantially opposite said first detector and said second light source is positioned substantially opposite said second detector and further comprising: a first light stop projecting toward said sources positioned between said first and said second detectors for shadowing said second detector from unscattered light from said first light source and for shadowing said first detector from unscattered light from said second light source.
Claim 5
Dependent Claim
62 words
An optical turbidimeter according to claim 3 wherein each of said light sources comprise: a light bulb; a beam forming lens system; and a light stop positioned between said bulb and said lens system for creating a shadow in a central portion of said beam, said shadow serving to reduce the scattering of light from the surface of said first light stop.
Claim 6
Dependent Claim
80 words
An optical turbidimeter according to claim 4 wherein said light sources are contained within a first water-tight housing, said housing comprising a source window associated with each of said sources of transmitting said beam from each of said sources into said medium, said light sources further comprising means for imaging the filament of said bulb on the outer surface of said window for reducing stray light from entering said medium from said bulb envelope, filament supports and other source structure.
Claim 7
Dependent Claim
72 words
An optical turbidimeter according to claim 5 wherein said detectors are contained within a second water-tight housing, said housing comprising a detector window associated with each of said detectors for transmitting light from said medium to said detectors, said housing further comprising means for supporting said detectors a predetermined distance from said windows for providing an equal field of view for said detectors to both scattered and unscattered light from said medium.
Claim 8
Dependent Claim
100 words
An optical turbidimeter according to claim 1 wherein said fifth and sixth signal generating means comprises means for generating sequentially said fifth signal proportional to the logarithm of the ratio of said first and said second signals and said sixth signal proportional to the logarithm of the ratio of said third and said fourth signals and wherein said seventh signal generating means comprises means for summing and dividing the sum of said fifth and said sixth signal by a predetermined amount for generating said seventh signal proportional to a root of the product of said fifth and said sixth signals.
Claim 9
Dependent Claim
78 words
An optical turbidimeter according to claim 7 further comprising means for generating a correction signal from each of said detectors proportional to the ambient light irradiating said medium and wherein said fifth and said sixth signal generating means further comprises means for changing the magnitude of said fifth and said sixth signal in proportion to the magnitude of said correction signal for providing a measure of the turbidity of said medium independent of ambient light irradiating said medium.
Claim 10
Dependent Claim
52 words
An optical turbidimeter according to claim 2 wherein said passageway between said source and said detectors for receiving said medium comprises a cross-shaped housing with four mutually perpendicular radially extending arms and wherein opposing ones of said arms serve to contain one of said light sources and one of said detectors respectively.
Claim 11
Dependent Claim
60 words
An optical turbidimeter according to claim 9 wherein each of said light sources comprise: a light bulb; a beam forming lens system for forming a beam from said light source; and a light stopping aperture located in the radial arm containing said light source for preventing said beam from illuminating the walls of said arm perpendicular thereto containing said detector.
Claim 12
Dependent Claim
78 words
An optical turbidimeter according to claim 10 wherein said light sources are contaIned within a first watertight housing, said housing comprising a source window associated with each of said sources of transmitting said beam from each of said sources into said medium, said light further comprising means for imaging the filament of said bulb on the outer surface of said window for reducing stray light from entering said medium from said bulb envelope, filament supports and other structure.
Claim 13
Dependent Claim
72 words
An optical turbidimeter according to claim 11 wherein said detectors are contained within a second watertight housing, said housing comprising a detector window associated with each of said detectors for transmitting light from said medium to said detectors, said housing further comprising means for supporting said detectors a predetermined distance from said windows for providing an equal field of view for said detectors to both scattered and unscattered light from said medium.
Claim 14
Dependent Claim
100 words
An optical turbidimeter according to claim 9 wherein said fifth and sixth signal generating means comprises means for generating sequentially said fifth signal proportional to the logarithm of the ratio of said first and said second signals and said sixth signal proportional to the logarithm of the ratio of said third and said fourth signals and wherein said seventh signal generating means comprises means for summing and dividing the sum of said fifth and said sixth signal by a predetermined amount for generating said seventh signal proportional to a root of the product of said fifth and said sixth signals.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-26 | 1977-05-28 | 1977-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-26 | 1981-05-28 | 1981-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-26 | 1985-05-28 | 1985-11-27 | $7700.00 | Window Closed / Lapsed |