US3908441A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Level detecting device
Assignee: FRANCAISE D'INSTRUMENTS DE CONTROLE ET D'ANALYSES Ste
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Filing: 1973-05-21
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Granted: 1975-09-30
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Expires: 1993-05-21
Abstract
Abstract A device for detecting the level of a liquid in a transparent tube including a radiation source to be placed facing a region of the periphery of the tube and a photocell to be placed facing a second zone of the tube periphery to receive radiation totally reflected from the internal face of the tube which has been wetted by a liquid, and which contains air rather than liquid. The device may be embodied in an automatic viscometer especially for coloured or opaque liquids.
Inventors
- 👤 Jean M Virloget
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:44
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/22; G01F23/28; G01F23/284; G01F23/292; G01F23/2921
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
161 words
A device for detecting the level of a liquid in a tube at least at a predetermined region of the tube, said device comprising a transparent tube containing a liquid which is displaced in the tube and which forms a displaceable meniscus in the tube, a radiation source disposed on one side of the tube with regard to the predetermined region thereof, said radiation source comprising means for emitting light impulses incident on a first zone of the periphery of the tube at said predetermined region, the emitting means comprising a pulse source including a circuit containing a current pulse generator means, a photoelectric cell sensitive to the presence and absence of said light impulses located in facing relation with a second zone of the periphery of the tube in said region for receiving that fraction of the radiation which has undergone total reflection in proximity with the internal face of the tube when the tube contains air instead of liquid.
Claim 2
Independent Claim
161 words
A device for detecting the level of a liquid in a tube at least at a predetermined region of the tube, said device comprising a transparent tube containing a liquid which is displaced in the tube and which forms a displaceable meniscus in the tube, a radiation source disposed on one side of the tube with regard to the predetermined region thereof, said radiation source comprising means for emitting light impulses incident on a first zone of the periphery of the tube at said predetermined region, the emitting means comprising a pulse source including a circuit containing a current pulse generator means, a photoelectric cell sensitive to the presence and absence of said light impulses located in facing relation with a second zone of the periphery of the tube in said region for receiving that fraction of the radiation which has undergone total reflection in proximity with the internal face of the tube when the tube contains air instead of liquid.
Claim 3
Dependent Claim
17 words
A device as claimed in claim 1 wherein the emitted light impulses are in the infrared band.
Claim 4
Dependent Claim
38 words
A device as claimed in claim 1 wherein the means for emitting light impulses is operable to emit pulses having a duration of the order of a few micro-seconds for a period of from one to five milliseconds.
Claim 5
Dependent Claim
26 words
A device as claimed in claim 1 wherein the means for emitting light impulses comprises a diode of a gallium arsenide emitting radiation at 9000 A.
Claim 6
Dependent Claim
23 words
A device as claimed in claim 1 wherein the photoelectric cell comprises a phototransistor and a pulse transmission capacitor coupled to the phototransistor.
Claim 7
Dependent Claim
17 words
A device as claimed in claim 1 wherein the emitting means further comprises a light emitting diode.
Claim 8
Dependent Claim
253 words
An automatic viscometer comprising a transparent tube containing a liqued which is displaced in the tube and which forms a displaceable meniscus in the tube, means for detecting the passage of the meniscus at an upper and a lower level in said tube comprising a first radiation source at the upper level of the tube, a second radiation source at the lower level in the tube, each radiation source comprising means for emitting light impulses at the periphery of the tube at said respective levels, each emitting means comprising a pulse source including a circuit containing a current pulse generator means, each of said emitting means being operable to emit impulses having a duration of the order of a few microseconds for a period of from one to five milliseconds, a photoelectric cell at each of said levels associated with a respective radiation source and sensitive to the absence and presence of light impulses from said source, each cell being in facing relation with said tube in a portion of the periphery thereof angularly offset from the portion facing the associated radiation source for receiving that fraction of the radiation which has undergone total reflection at the internal face of the tube when the tube contains air instead of liquid, each photoelectric cell comprising a phototransistor and a pulse transmission capacitor connected to the phototransistor, said viscometer further comprising a monstable circuit connected to both of the monstable ciRcuits and a counter, associated with a time base, conected to said bistable trigger curcuits.
Claim 9
Dependent Claim
253 words
An automatic viscometer comprising a transparent tube containing a liqued which is displaced in the tube and which forms a displaceable meniscus in the tube, means for detecting the passage of the meniscus at an upper and a lower level in said tube comprising a first radiation source at the upper level of the tube, a second radiation source at the lower level in the tube, each radiation source comprising means for emitting light impulses at the periphery of the tube at said respective levels, each emitting means comprising a pulse source including a circuit containing a current pulse generator means, each of said emitting means being operable to emit impulses having a duration of the order of a few microseconds for a period of from one to five milliseconds, a photoelectric cell at each of said levels associated with a respective radiation source and sensitive to the absence and presence of light impulses from said source, each cell being in facing relation with said tube in a portion of the periphery thereof angularly offset from the portion facing the associated radiation source for receiving that fraction of the radiation which has undergone total reflection at the internal face of the tube when the tube contains air instead of liquid, each photoelectric cell comprising a phototransistor and a pulse transmission capacitor connected to the phototransistor, said viscometer further comprising a monstable circuit connected to both of the monstable ciRcuits and a counter, associated with a time base, conected to said bistable trigger curcuits.
Claim 10
Dependent Claim
17 words
A viscometer as claimed in claim 7 wherein the emitted light impulses are in the infrared band.
Claim 11
Dependent Claim
26 words
A viscometer as claimed in claim 7 wherein the means for emitting light impulses further comprises a diode of a gallium arsenide emitting radiation at 9000A.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-29 | 1979-03-31 | 1979-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-29 | 1983-03-31 | 1983-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-29 | 1987-03-31 | 1987-09-30 | $7700.00 | Window Closed / Lapsed |