US3790798A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and system for the infrared analysis of gases
Assignee: METRO HYDRAULICS Inc
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Filing: 1972-08-18
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Granted: 1974-02-05
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Expires: 1992-08-18
Abstract
Abstract A dual path analyzer and a single path analyzer are disclosed, each for determining the concentration of one or more gaseous components in a mixture of gases. The preferred analyzer is a single path instrument which includes a source of infrared energy, a detector for the energy, a sample cell for the gas mixture positioned between the source and detector, and a filter wheel having a plurality of filters and a source blocking device positioned between the sample cell and detector for sequentially interposing the filters and the source blocking device between the source and the detector. Means are provided for amplifying the output signal of the detector and for processing the signal to provide a direct readout display which indicates the concentration of the gaseous components being analyzed. The processing electronics preferably include provision for calibrating the analyzer with clean ambient air, for compensating for background levels of radiation, and for correcting the displayed output signal for the effects of absorption band interferences between two or more gases in the gas mixture. The structure of the dual path analyzer includes a source of infrared energy, a detector for the energy, a sample cell for the gas mixture, a cell for a reference gas, and optical path means between the source and detector for sequentially directing the source energy through the sample cell, the reference cell, and through neither cell. Processing electronics similar to the single path instrument can be incorporated to compensate for background radiation and absorption band interferences.
Inventors
- 👤 J Lennington
- 👤 S Sternberg
- 👤 J Young
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:00
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/314; G01N21/35; G01N21/3504; G01N2201/00; G01N2201/12; G01N2201/121; G01N2201/1215
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
597 words
A spectrophotometer having a predetermined operational cycle for analyzing a fluid to determine the concentration of a component therein on each of a plurality of operational cycles thereof comprising: a source of infrared energy adapted for radiating said infrared energy along a single optical path; a detector of said infrared energy located on said single path for receiving at least a portion of said infrared energy radiated by said source and for providing an output signal which is representative of the intensity of said received infrared energy; chamber means located on said single path intermediate said source and detector for receiving said fluid to be analyzed, said chamber means having window means disposed on said single path for transmission of said infrared energy through said chamber means; means carrying at least two filters and an opaque source blocking means being adapted for sequentially interposing said filters and said opaque source blocking means in said optical path intermediate said source and said detector with one such interposition of each of said filters and said opaque source blocking means defining one of said plurality of operational cycles of said spectrophotometer, each of said filters being adapted for transmission of infrared energy within a preselected narrow band, a first of said filters being adapted to transmit infrared energy within a band at which said component has a definable high characteristic absorption, a second of said filters being adapted to transmit infrared energy within a band at which said component of said fluid has a definable low characteristic absorption, said opaque source blocking means being within substantially the same environment as said first and second filters so as to be at substantially the same temperature thereof thereby emitting wide band infrared energy which is generally the same as the wide band infrared energy emitted by said filters; and means operatively associated with said detecting means for responding to said detector output signal including first means for receiving a component detector output signal received when said first filter is interposed in said single path so as to be representative of the intensity of infrared energy transmitted through said component filter on respective ones of said operational cycles and for storing said component detector output signal on respective ones of said operational cycles substantially independently of component detector output signals stored on previous ones of said operational cycles, second means for receiving a reference detector output signal received when said second filter is interposed in said single path so as to be representative of the intensity of infrared energy transmitted through said reference filter on respective ones of said operational cycles and for storing said component detector output signal on respective ones of said operational cycles substantially independently of reference detector output signals stored on previous ones of said operational cycles, and third means for receiving a background detector output signal when said opaque source blocking means is interpOsed in said path so as to be representative of the intensity of infrared energy radiated by said opaque source blocking means on respective ones of said operational cycles and for storing said background detector output signal on respective ones of said operational cycles substantially independently of background detector output signals stored on previous ones of said operational cycles, and means for subtracting said background signal from at least one of said component detector output signal and said reference detector output signal on respective ones of said operational cycles for providing a background compensated detector output signal and utilizing said background compensated detector output signal to provide a measure of the concentration of said component.
Claim 2
Dependent Claim
597 words
A spectrophotometer having a predetermined operational cycle for analyzing a fluid to determine the concentration of a component therein on each of a plurality of operational cycles thereof comprising: a source of infrared energy adapted for radiating said infrared energy along a single optical path; a detector of said infrared energy located on said single path for receiving at least a portion of said infrared energy radiated by said source and for providing an output signal which is representative of the intensity of said received infrared energy; chamber means located on said single path intermediate said source and detector for receiving said fluid to be analyzed, said chamber means having window means disposed on said single path for transmission of said infrared energy through said chamber means; means carrying at least two filters and an opaque source blocking means being adapted for sequentially interposing said filters and said opaque source blocking means in said optical path intermediate said source and said detector with one such interposition of each of said filters and said opaque source blocking means defining one of said plurality of operational cycles of said spectrophotometer, each of said filters being adapted for transmission of infrared energy within a preselected narrow band, a first of said filters being adapted to transmit infrared energy within a band at which said component has a definable high characteristic absorption, a second of said filters being adapted to transmit infrared energy within a band at which said component of said fluid has a definable low characteristic absorption, said opaque source blocking means being within substantially the same environment as said first and second filters so as to be at substantially the same temperature thereof thereby emitting wide band infrared energy which is generally the same as the wide band infrared energy emitted by said filters; and means operatively associated with said detecting means for responding to said detector output signal including first means for receiving a component detector output signal received when said first filter is interposed in said single path so as to be representative of the intensity of infrared energy transmitted through said component filter on respective ones of said operational cycles and for storing said component detector output signal on respective ones of said operational cycles substantially independently of component detector output signals stored on previous ones of said operational cycles, second means for receiving a reference detector output signal received when said second filter is interposed in said single path so as to be representative of the intensity of infrared energy transmitted through said reference filter on respective ones of said operational cycles and for storing said component detector output signal on respective ones of said operational cycles substantially independently of reference detector output signals stored on previous ones of said operational cycles, and third means for receiving a background detector output signal when said opaque source blocking means is interpOsed in said path so as to be representative of the intensity of infrared energy radiated by said opaque source blocking means on respective ones of said operational cycles and for storing said background detector output signal on respective ones of said operational cycles substantially independently of background detector output signals stored on previous ones of said operational cycles, and means for subtracting said background signal from at least one of said component detector output signal and said reference detector output signal on respective ones of said operational cycles for providing a background compensated detector output signal and utilizing said background compensated detector output signal to provide a measure of the concentration of said component.
Claim 3
Dependent Claim
20 words
A spectrophotometer of claim 1 wherein said means carrying said filters is disposed intermediate said chamber means and said detector.
Claim 4
Dependent Claim
19 words
A spectrophotometer of claim 1 wherein said first means, said second means, and said third means are sample-and-hold circuits.
Claim 5
Dependent Claim
54 words
A spectrophotometer of claim 1 wherein said means for subtracting said background signal from at least one of said component detector output signal and said reference detector output signal subtracts said background signal from both of said component detector output signal and said reference detector output signal on respective ones of said operational cycles.
Claim 6
Dependent Claim
41 words
A spectrophotometer according to claim 4 wherein said means for subtracting said background signal from said component and reference detector output signal provides a ratio of said background compensated component detector output signal and said background compensated reference detector output signal.
Claim 7
Dependent Claim
477 words
A spectrophotometer for analyzing fluid to determine the concentration of component therein comprising: a source of radiant energy adapted for radiating said energy along a single optical path; a detector of said radiant energy located on said single path for receiving at least a portion of said energy radiated by said source and for providing an output signal which is representative of the intensity of said received radiant energy; chamber means located on said single path intermediate said source and detector for receiving said fluid to be analyzed, said chamber means having window means disposed on said single path for transmission of said radiant energy through said chamber; means carrying at least two filters and an opaque source blocking means being adapted for sequentially interposing said filters and said opaque source blocking means in said optical path intermediate said source and said detector, each of said filters being adapted for transmission of radiant energy within a preselected narrow band, a first of said filters being adapted to transmit radiant energy within a band at which said component has a definable high characteristic absorption, a second of said filters being adapted to transmit radiant energy within a band at which all components of said fluid have a definable low characteristic absorption, said opaque source blocking means being within substantially the same environment as said first and second filters thereby emitting wide band radiant energy which is generally the same as wide band radiant energy emitted by said filters; said carrying means being positioned intermediate said chamber means and said detector being adapted for positioning said opaque source blocking means in sufficient proximity to said detector when interposed in said single path so that said opaque source blocking means substantially fills the detector field of view to substantially constitute the only source of background radiation when interposed in said path, and being further adapted for positioning said filters at the same location with respect to said detector as said opaque blocking means when interposed in said single path; and means operatively associated with said detecting means for responding to said detector output signal including first meaNs for receiving and storing a component detector ouput signal received when said first filter in interposed in said single path, second means for receiving and storing a reference detector output signal received when said second filter is interposed in said single path, and third means for receiving and storing a background detector output signal when said opaque source blocking means is interposed in said path, and means for compensating at least one of said component detector output signal and said reference detector output signal in accordance with said background signal and for utilizing said background compensated one of said component and reference detector output signals to provide a background compensated spectrophotometer output signal which is a measure of the concentration of said component.
Claim 8
Dependent Claim
477 words
A spectrophotometer for analyzing fluid to determine the concentration of component therein comprising: a source of radiant energy adapted for radiating said energy along a single optical path; a detector of said radiant energy located on said single path for receiving at least a portion of said energy radiated by said source and for providing an output signal which is representative of the intensity of said received radiant energy; chamber means located on said single path intermediate said source and detector for receiving said fluid to be analyzed, said chamber means having window means disposed on said single path for transmission of said radiant energy through said chamber; means carrying at least two filters and an opaque source blocking means being adapted for sequentially interposing said filters and said opaque source blocking means in said optical path intermediate said source and said detector, each of said filters being adapted for transmission of radiant energy within a preselected narrow band, a first of said filters being adapted to transmit radiant energy within a band at which said component has a definable high characteristic absorption, a second of said filters being adapted to transmit radiant energy within a band at which all components of said fluid have a definable low characteristic absorption, said opaque source blocking means being within substantially the same environment as said first and second filters thereby emitting wide band radiant energy which is generally the same as wide band radiant energy emitted by said filters; said carrying means being positioned intermediate said chamber means and said detector being adapted for positioning said opaque source blocking means in sufficient proximity to said detector when interposed in said single path so that said opaque source blocking means substantially fills the detector field of view to substantially constitute the only source of background radiation when interposed in said path, and being further adapted for positioning said filters at the same location with respect to said detector as said opaque blocking means when interposed in said single path; and means operatively associated with said detecting means for responding to said detector output signal including first meaNs for receiving and storing a component detector ouput signal received when said first filter in interposed in said single path, second means for receiving and storing a reference detector output signal received when said second filter is interposed in said single path, and third means for receiving and storing a background detector output signal when said opaque source blocking means is interposed in said path, and means for compensating at least one of said component detector output signal and said reference detector output signal in accordance with said background signal and for utilizing said background compensated one of said component and reference detector output signals to provide a background compensated spectrophotometer output signal which is a measure of the concentration of said component.
Claim 9
Dependent Claim
89 words
A spectrophotometer of claim 6 wherein said means for compensating at least one of said component detector output signal and said reference detector output signal in accordance with said background signal compensates both of said component detector output signal and said reference detector output signal in accordance with said background signal and provides a ratio of said background compensated component detector output signal and said background compensated reference detector output signal to provide said background compensated spectrophotometer output signal which is a measure of the concentration of said component.
Claim 10
Dependent Claim
11 words
A spectrophotometer of claim 6 wherein said source radiates infrared energy.
Claim 11
Dependent Claim
19 words
A spectrophotometer of claim 6 wherein said first means, said second means, and said third means are sample-and-hold circuits.
Claim 12
Dependent Claim
101 words
A spectrophotometer according to claim 7 wherein said means for compensating said component and reference detector output signals in accordance with said background signal and for providing a ratio of said component and reference detector output signals comprises means for subtracting said component detector output signal from said reference detector output signal to provide a first determination output signal, means for subtracting said background detector output signal from said reference detector output signal to provide a second determination signal, and means for obtaining the ratio of said first and second determination output signals to provide said background compensated spectrophotometer output signal.
Claim 13
Dependent Claim
359 words
A spectrophotometer having a predetermined operational cycle for analyzing fluids through which infrared energy is transmitted to determine the concentration of a component therein on each of a plurality of operational cycles thereof comprising: detecting means for receiving said infrared energy after transmission through said fluid and for providing an output signal representative of the intensity of said received infrared energy; first component filter means having a predetermined bandpass at which a first component has a predetermined low transmissivity of said infrared energy, said first component filter means being adapted for transmission of said infrared energy therethrough to said detecting means at a first preselected time in each said operational cycle; reference filter means having a predetermined bandpass at which said first component of said fluid has a predetermined high transmissivity of said infrared energy, said reference filter means being adapted for transmission of said infrared energy therethrough to said detecting means at a second preselected time in each said operational cycle; means for interrupting the transmission of said infrared energy to said detecting means at a third preselected time in each said operational cycle; and means for receiving the output signal of said detecting means and for storing a reference signal representative of the intensity of infrared energy transmitted through said fluid and said reference filter means on respective ones of said operational cycles independently of reference signals stored on previous ones of said operational cycles, fOr storing a first component signal representative of the intensity of said infrared energy transmitted through said fluid and said first component filter means on respective ones of said operational cycles independently of first component signals stored on previous ones of said operational cycles, and for storing at least one background signal representative of the detector output signal with the transmission of said infrared energy interrupted by said interrupting means on said respective ones of said operational cycles independently of background signals stored on previous ones of said operational cycles, said detector output signal receiving means further including means for compensating at least one of said stored reference signal and said stored first component signal in accordance with said stored background signal.
Claim 14
Dependent Claim
359 words
A spectrophotometer having a predetermined operational cycle for analyzing fluids through which infrared energy is transmitted to determine the concentration of a component therein on each of a plurality of operational cycles thereof comprising: detecting means for receiving said infrared energy after transmission through said fluid and for providing an output signal representative of the intensity of said received infrared energy; first component filter means having a predetermined bandpass at which a first component has a predetermined low transmissivity of said infrared energy, said first component filter means being adapted for transmission of said infrared energy therethrough to said detecting means at a first preselected time in each said operational cycle; reference filter means having a predetermined bandpass at which said first component of said fluid has a predetermined high transmissivity of said infrared energy, said reference filter means being adapted for transmission of said infrared energy therethrough to said detecting means at a second preselected time in each said operational cycle; means for interrupting the transmission of said infrared energy to said detecting means at a third preselected time in each said operational cycle; and means for receiving the output signal of said detecting means and for storing a reference signal representative of the intensity of infrared energy transmitted through said fluid and said reference filter means on respective ones of said operational cycles independently of reference signals stored on previous ones of said operational cycles, fOr storing a first component signal representative of the intensity of said infrared energy transmitted through said fluid and said first component filter means on respective ones of said operational cycles independently of first component signals stored on previous ones of said operational cycles, and for storing at least one background signal representative of the detector output signal with the transmission of said infrared energy interrupted by said interrupting means on said respective ones of said operational cycles independently of background signals stored on previous ones of said operational cycles, said detector output signal receiving means further including means for compensating at least one of said stored reference signal and said stored first component signal in accordance with said stored background signal.
Claim 15
Dependent Claim
42 words
A spectrophotometer according to claim 11 wherein said compensated one of said reference signal and said first component signal are compensated by subtraction of said stored background signal from said one of said stored first component signal and said stored reference signal.
Claim 16
Dependent Claim
52 words
A spectrophotometer according to claim 11 wherein said means for compensating at least one of said stored reference signal and said stored first component signal in accordance with said stored background signal compensates both of said stored reference signal and said stored first component signal in accordance with said stored background signal.
Claim 17
Dependent Claim
34 words
A spectrophotometer according to claim 13 wherein said reference signal and said first component signal are compensated by subtraction of said background signal from each of said first component signal and said reference signal.
Claim 18
Dependent Claim
26 words
A spectrophotometer according to claim 13 wherein a ratio is provided representative of said background compensated first component signal divided by said background compensated reference signal.
Claim 19
Dependent Claim
98 words
A spectrophotometer according to claim 11 further including: second component filter means having a predetermined bandpass at which a second component has a predetermined low transmissivity of said infrared energy, said second component filter means being adapted for transmission of said infrared energy therethrough to said detecting means; said detector output signal receiving means further storing a second component signal representative of the intensity of said infrared energy transmitted through said fluid and said second component filter means on respective ones of said operational cycles independently of second component signals stored on previous ones of said operational cycles.
Claim 20
Dependent Claim
21 words
A spectrophotometer according to claim 16 further including means for compensating said second component signal in accordance with said background signal.
Claim 21
Dependent Claim
39 words
A spectrophotometer according to claim 16 wherein said detector output receiving means further includes spectrum interference compensating means for compensating said first component signal for spectrum interference due to a concentration of said second component in said analyzed fluid.
Claim 22
Dependent Claim
39 words
A spectrophotometer according to claim 18 wherein said detector output receiving means further includes spectrum interference compensating means for compensating said second component signal for spectrum interference due to a concentration of said first component in said analyzed fluid.
Claim 23
Dependent Claim
51 words
A spectrophotometer according to claim 16 wherein said output signal receiving means further includes spectrum interference compensating means receiving said second component signal for compensating said first component signal for spectrum interference due to a concentration of said second component in said analyzed fluid in accordance with said second component signal.
Claim 24
Dependent Claim
54 words
A spectrophotometer according to claim 20 wherein said output signal receiving means further includes spectrum interference compensating means receiving said stored first component signal for compensating said stored second component signal for spectrum interference due to a concentRation of said first component in said analyzed fluid in accordance with said stored first component signal.
Claim 25
Dependent Claim
48 words
A spectrophotometer according to claim 20 wherein said spectrum interference compensating means modifies said stored second component signal and compensates said stored first component signal for spectrum interference due to a concentration of a second component in said analyzed fluid in accordance with said modified second component signal.
Claim 26
Dependent Claim
19 words
A spectrophotometer according to claim 22 wherein said spectrum interference compensating means linearly modifies said stored second component signal.
Claim 27
Dependent Claim
23 words
A spectrophotometer according to claim 23 wherein said spectrum interference compensating means includes resistive means for linearly modifying said stored second component signal.
Claim 28
Dependent Claim
19 words
A spectrophotometer according to claim 22 wherein said spectrum interference compensating means non-linearly modifies said stored second component signal.
Claim 29
Dependent Claim
24 words
A spectrophotometer according to claim 25 wherein said spectrum interference compensation means modifies said stored second component signal in accordance with a logarithmic relationship.
Claim 30
Dependent Claim
20 words
A spectrophotometer according to claim 26 wherein said spectrum interference compensation means additionally linearly modifies said stored second component signal.
Claim 31
Dependent Claim
13 words
A spectrophotometer according to claim 20 wherein said second component is water vapor.
Claim 32
Dependent Claim
486 words
A spectrophotometer having a predetermined operational cycle for analyzing fluids through which infrared energy is transmitted to determine the concentration of a component therein on each of a plurality of operational cycles thereof comprising: detecting means having a predetermined field of view in which said infrared energy is received after transmission through said fluid, said detecting means providing an output signal representative of the intensity of said received infrared energy; means carrying at least two filters and an opaque source blocking means being adapted for sequentially interposing said filters and said opaque source blocking means intermediate said fluid and said detecting means with one such interposition of each of said filters and said opaque source blocking means defining one said predetermined operational cycle of said spectrophotometer, a first of said filters being adapted to transmit infrared energy within a first narrow band at which said component has a definable high-characteristic, absorption, a second of said filters being adapted to transmit infrared energy within a second narrow band at which said component of said fluid has a definable low-characteristic absorption, said opaque source blocking means being within substantially the same environment as said first and second filters so as to be at substantially the same temperature thereof thereby emitting wide band infrared energy which is generally the same as wide band infrared energy emitted by said filters; and means for receiving the output signal of said detecting means and for storing a reference signal representative of the intensity of infrared energy transmitted through said fluid and said reference filter means on respective ones of said operational cycles independently of reference signals provided on previous ones of said operational cycles, for storing a first component signal representative of the intensity of said infrared energy transmitted through said fluid and said first component filter means on respective ones of said operational cycles independently of said first component signals provided on previous ones of said operational cycles, and for storing at least one background signal representative of the detector output signal with said opaque source blocking means interposed between said fluid and said detecting means on respective ones of said operational cycles independently of background signals provided on previous ones of said operational cycles, said detector output signal receiving means further including means for compensating at least one Of said stored reference signal and said stored first component signal in accordance with said stored background signal; said carrying means being adapted to position said first and second filters and said opaque source blocking means in close proximity to said detecting means when each is interposed between said fluid and said detecting means so that said carrying means substantially fills said predetermined field of view of said detecting means to substantially constitute the only source of background radiation of infrared energy when each of said first component signal, said reference signal and said background signal is stored by said detecting means.
Claim 33
Dependent Claim
486 words
A spectrophotometer having a predetermined operational cycle for analyzing fluids through which infrared energy is transmitted to determine the concentration of a component therein on each of a plurality of operational cycles thereof comprising: detecting means having a predetermined field of view in which said infrared energy is received after transmission through said fluid, said detecting means providing an output signal representative of the intensity of said received infrared energy; means carrying at least two filters and an opaque source blocking means being adapted for sequentially interposing said filters and said opaque source blocking means intermediate said fluid and said detecting means with one such interposition of each of said filters and said opaque source blocking means defining one said predetermined operational cycle of said spectrophotometer, a first of said filters being adapted to transmit infrared energy within a first narrow band at which said component has a definable high-characteristic, absorption, a second of said filters being adapted to transmit infrared energy within a second narrow band at which said component of said fluid has a definable low-characteristic absorption, said opaque source blocking means being within substantially the same environment as said first and second filters so as to be at substantially the same temperature thereof thereby emitting wide band infrared energy which is generally the same as wide band infrared energy emitted by said filters; and means for receiving the output signal of said detecting means and for storing a reference signal representative of the intensity of infrared energy transmitted through said fluid and said reference filter means on respective ones of said operational cycles independently of reference signals provided on previous ones of said operational cycles, for storing a first component signal representative of the intensity of said infrared energy transmitted through said fluid and said first component filter means on respective ones of said operational cycles independently of said first component signals provided on previous ones of said operational cycles, and for storing at least one background signal representative of the detector output signal with said opaque source blocking means interposed between said fluid and said detecting means on respective ones of said operational cycles independently of background signals provided on previous ones of said operational cycles, said detector output signal receiving means further including means for compensating at least one Of said stored reference signal and said stored first component signal in accordance with said stored background signal; said carrying means being adapted to position said first and second filters and said opaque source blocking means in close proximity to said detecting means when each is interposed between said fluid and said detecting means so that said carrying means substantially fills said predetermined field of view of said detecting means to substantially constitute the only source of background radiation of infrared energy when each of said first component signal, said reference signal and said background signal is stored by said detecting means.
Claim 34
Dependent Claim
44 words
A spectrophotometer according to claim 29 wherein said compensated one of said stored reference signal and said first stored component signal are compensated by subtraction of said stored background signal from said one of said stored first component signal and said stored reference signal.
Claim 35
Dependent Claim
52 words
A spectrophotometer according to claim 29 wherein said means for compensating at least one of said stored reference signal and said stored first component signal in accordance with said stored background signal compensates both of said stored reference signal and said stored first component signal in accordance with said stored background signal.
Claim 36
Dependent Claim
39 words
A spectrophotometer according to claim 31 wherein said stored reference signal and said stored first component signal are compensated by subtraction of said stored background signal from each of said stored first component signal and said stored reference signal.
Claim 37
Dependent Claim
26 words
A spectrophotometer according to claim 32 wherein a ratio is provided representative of said background compensated first component signal divided by said background compensated reference signal.
Claim 38
Dependent Claim
44 words
A spectrophotometer according to claim 29 wherein said carrying means includes wheel means carrying said two filters and said opaque source blocking means which is rotatable for sequentially interposing said filters and said opaque source blocking means intermediate said fluid and said detecting means.
Claim 39
Dependent Claim
23 words
A spectrophotometer according to claim 34 wherein said two filters and said opaque source blocking means are circumferentially spaced on said wheel means.
Claim 40
Independent Claim
195 words
A method for analyzing fluids through which energy is transmitted to determine the concentration of component therein comprising the steps of: receiving and detecting at least a portion of said energy transmitted through said fluid to provide in output signal representative of the intensity of the received energy; filtering said energy at a predetermined reference bandpass in which all components of the fluid have a predetermined high transmissivity of said energy prior to said detecting and receiving of said energy; filtering said energy at a predetermined component bandpass in which a first component has a predetermined low transmissivity of said energy prior to said detecting and receiving of said energy; interrupting the transmission of said energy to said detecting means at selected times; obtaining a reference signal representative of the intensity of energy transmitted through said fluid while filtering at said reference bandpass; obtaining a first component signal representative of the intensity of said energy transmitted through said fluid while filtering at said filter bandpass; obtaining a background signal while the transmission of said energy is interrupted by said interrupting means; and compensating said reference and first component signals in accordance with said background signal.
Claim 41
Independent Claim
195 words
A method for analyzing fluids through which energy is transmitted to determine the concentration of component therein comprising the steps of: receiving and detecting at least a portion of said energy transmitted through said fluid to provide in output signal representative of the intensity of the received energy; filtering said energy at a predetermined reference bandpass in which all components of the fluid have a predetermined high transmissivity of said energy prior to said detecting and receiving of said energy; filtering said energy at a predetermined component bandpass in which a first component has a predetermined low transmissivity of said energy prior to said detecting and receiving of said energy; interrupting the transmission of said energy to said detecting means at selected times; obtaining a reference signal representative of the intensity of energy transmitted through said fluid while filtering at said reference bandpass; obtaining a first component signal representative of the intensity of said energy transmitted through said fluid while filtering at said filter bandpass; obtaining a background signal while the transmission of said energy is interrupted by said interrupting means; and compensating said reference and first component signals in accordance with said background signal.
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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) | 1977-02-04 | 1977-08-06 | 1978-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-04 | 1981-08-06 | 1982-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-04 | 1985-08-06 | 1986-02-05 | $7700.00 | Window Closed / Lapsed |