US3843269A
Expired / Lapsed
US
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Process and apparatus for photometric determination of the extinction of a sample
Assignee: Carl Zeiss AG
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Filing: 1973-11-19
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Granted: 1974-10-22
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Expires: 1993-11-19
Abstract
Abstract A process and apparatus for photometric determination of the extinction of a sample with a photoelectric measuring instrument. The radiation to be measured strikes the photoelectric receiver only on a path through the measurement cell. The thickness of the sample is modulated periodically, to produce in the receiver current an alternating current portion and a direct current portion. The alternating current portion of the signal is divided by the direct current portion by means of a quotient computer, thus giving a value which is directly proportional to the extinction sought.
Inventors
- 👤 G Hohberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 08:58
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/59
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
94 words
Process for the photometric determination of the extinction of a sample with a photoelectric measuring instrument in which the measurement radiation strikes the photoelectric receiver only over a path through a measurement cell, characterized by the fact that the length of path of the radiation passing through the sample is changed by a small amount periodically with the frequency omega , that an a.c. portion of the frequency omega of the resultant measurement signal and a d.c. portion thereof are separated, and that the quotient of the separated signal portions is formed and indicated.
Claim 2
Dependent Claim
94 words
Process for the photometric determination of the extinction of a sample with a photoelectric measuring instrument in which the measurement radiation strikes the photoelectric receiver only over a path through a measurement cell, characterized by the fact that the length of path of the radiation passing through the sample is changed by a small amount periodically with the frequency omega , that an a.c. portion of the frequency omega of the resultant measurement signal and a d.c. portion thereof are separated, and that the quotient of the separated signal portions is formed and indicated.
Claim 3
Dependent Claim
28 words
Process according to claim 1, characterized by the fact that the division of the a.c. signal by the d.c. signal is effected automatically in a known quotient computer.
Claim 4
Dependent Claim
38 words
Process according to claim 1, characterized by the fact that the change in the length of path of the radiation which passes through the sample is effected by periodic change of the thickness of layer of the sample.
Claim 5
Dependent Claim
112 words
Apparatus for photometric determination of the extinction of a sample with a photoelectric measuring instrument, comprising means for holding a sample, means for projecting radiation along a path passing through a sample in said holding means, a photoelectric receiver positioned to receive only radiation which has passed through said sample, means for changing the length of path of the radiation passing through the sample by a small amount periodically with the frequency omega , means for separating an a.c. portion of the frequency omega of a resultant measurement signal from a d.c. portion thereof, and means for forming and indicating a quotient resulting from dividing said a.c. portion by said d.c. portion.
Claim 6
Dependent Claim
112 words
Apparatus for photometric determination of the extinction of a sample with a photoelectric measuring instrument, comprising means for holding a sample, means for projecting radiation along a path passing through a sample in said holding means, a photoelectric receiver positioned to receive only radiation which has passed through said sample, means for changing the length of path of the radiation passing through the sample by a small amount periodically with the frequency omega , means for separating an a.c. portion of the frequency omega of a resultant measurement signal from a d.c. portion thereof, and means for forming and indicating a quotient resulting from dividing said a.c. portion by said d.c. portion.
Claim 7
Dependent Claim
31 words
Apparatus according to claim 4, characterized by the fact that a radiation-permeable wedge is contained in a liquid or gaseous sample and is moved periodically perpendicular to the direction of radiation.
Claim 8
Dependent Claim
15 words
Apparatus according to claim 5, wherein said wedge is a wedge of continuously varying thickness.
Claim 9
Dependent Claim
14 words
Apparatus according to claim 5, wherein said wedge is a wedge of stepped form.
Claim 10
Dependent Claim
41 words
Apparatus according to claim 4, characterized by the fact that said holding means is in the form of a bellows cup which has at least one radiation-permeable wall portion which is periodically movable in the direction of travel of the radiation.
Claim 11
Dependent Claim
36 words
Apparatus according to claim 4, characterized by the fact that two light pipes dip into a liquid or gaseous sample, at least one of them being periodically movable so as to change the distance between them.
Claim 12
Dependent Claim
55 words
Apparatus according to claim 4, characterized by the fact that the sample or a cup in which the sample is contained has the shape of a continuous or stepped wedge, and that the radiation passing through the sample is so deflected by optical-mechanical means that the path of radiation within the sample is periodically changed.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-21 | 1978-04-22 | 1978-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-21 | 1982-04-22 | 1982-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-21 | 1986-04-22 | 1986-10-22 | $7700.00 | Window Closed / Lapsed |