US3897153A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Phase and amplitude balance adjustment for a dual beam infrared gas analyzer
Assignee: Rosemount Inc
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Filing: 1973-07-23
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Granted: 1975-07-29
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Expires: 1993-07-23
Abstract
Abstract Phase and amplitude balance adjustment are provided for a gas analyzer of the type in which two infrared beams are generated, one passed through a cell containing a standard and the other through a cell containing a sample gas, constituents in which are to be detected and measured; and there is a detector which compares the energy absorption in the two cells to provide a measure of the gas content. In this type of gas detector there is a chopper consisting of a rotating shutter with two sectors which rotate in front of two apertures through which infrared beams are transmitted from two different infrared beam generators. Phase adjustment is accomplished mechanically by physically moving a mounting plate carrying the two infrared beam generators with respect to the position of the apertures. Amplitude balance adjustment is accomplished by adjusting the relative electrical energy supplied to the two infrared beam generators.
Inventors
- 👤 Charles A Keenan
- 👤 Carl N Cederstrand
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:29
CPC Classifications
G; G01; G01J; G01J1/00; G01J1/10; G01J1/20; G01J1/28; G01J1/30; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/35; G01N21/37
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
120 words
In a fluid analyzer of the twin beam type having a pair of beam sources and means for passing one beam through a sample and the other through a standard, a detector for comparing absorption by the standard and the sample, a moving shutter with a pair of vanes for intermittently interrupting the beams and means for varying the phase relationship between the beams with respect to the time of interruption, the improvement in phase adjustment means comprising: a common support for the beam sources and means for varying the relative position transversely to the beams of the common beam support and the shutter mounting for simultaneously, transversely varying the positions of the beams with respect to the shutter mounting.
Claim 2
Dependent Claim
120 words
In a fluid analyzer of the twin beam type having a pair of beam sources and means for passing one beam through a sample and the other through a standard, a detector for comparing absorption by the standard and the sample, a moving shutter with a pair of vanes for intermittently interrupting the beams and means for varying the phase relationship between the beams with respect to the time of interruption, the improvement in phase adjustment means comprising: a common support for the beam sources and means for varying the relative position transversely to the beams of the common beam support and the shutter mounting for simultaneously, transversely varying the positions of the beams with respect to the shutter mounting.
Claim 3
Dependent Claim
60 words
The apparatus described in claim 1 wherein the shutter comprises means mounted upon a rotatable shutter shaft having an axis of rotation and which is supported in bearing means and the adjusting means comprises means for moving one of said bearing means and said beam source common support relative to the other transversely with respect to said axis of rotation.
Claim 4
Dependent Claim
43 words
The apparatus described in claim 2 wherein the shutter bearing means and the beam source common support are mounted in a unit and the beam source common support is slidable in said unit transversely to the axis of rotation of the shutter shaft.
Claim 5
Dependent Claim
78 words
Apparatus described in claim 3 wherein the unit has a wall with a pair of apertures therein having edges, the shutter shaft extends through said wall with the shutter mounted in front of the wall and the beam sources mounted behind the wall, each at one of said apertures, whereby relative movement of the beam source common support and the bearing means varies the relative time of cut-off of the beam by the shutter at an aperture edge.
Claim 6
Dependent Claim
127 words
In the method of fluid analysis by comparison of radiant beam absorption in a standard and a sample including the step of intermittent beam interruption, the improvement which consists of overcoming unbalanced conditions resulting from errors in phase relationship and intensity relationship of the beams in the comparison process comprising the steps of: first adjusting the relative intensities of the beams until a minimum value of radiant beam absorption indication is obtained, then adjusting the time phase relationship between the instant when one beam is interrupted and the instant when the other beam is interrupted until the indication obtained most nearly falls to zero to enable most nearly zero readings to be obtained when the standard and the sample are identical and phase errors have been corrected.
Claim 7
Dependent Claim
127 words
In the method of fluid analysis by comparison of radiant beam absorption in a standard and a sample including the step of intermittent beam interruption, the improvement which consists of overcoming unbalanced conditions resulting from errors in phase relationship and intensity relationship of the beams in the comparison process comprising the steps of: first adjusting the relative intensities of the beams until a minimum value of radiant beam absorption indication is obtained, then adjusting the time phase relationship between the instant when one beam is interrupted and the instant when the other beam is interrupted until the indication obtained most nearly falls to zero to enable most nearly zero readings to be obtained when the standard and the sample are identical and phase errors have been corrected.
References Cited (Backward Citations)
US2933600A
Cited
US3729264A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-28 | 1979-01-27 | 1979-07-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-28 | 1983-01-27 | 1983-07-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-28 | 1987-01-27 | 1987-07-29 | $7700.00 | Window Closed / Lapsed |