US3794425A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Scanning infrared spectroscopic analyzer using rotating variable filter
Assignee: Shell USA Inc
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Filing: 1972-08-22
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Granted: 1974-02-26
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Expires: 1992-08-22
Abstract
Abstract A fast spectroscopic analyzer wherein chopped infrared light is passed through a sample cell, a rotating variable filter and to a detector. The angular position of the filter corresponds to various wave lengths of light and is used to synchronize a recording system, recording signals of interest.
Inventors
- 👤 V Smith
- 👤 R Bowers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:00
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/12; G01J5/00; G01J5/10; G01J5/34; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/314; G01J1/00; G01J1/42; G01J2001/4242; G01J2003/1226; G01J2003/1234; G01J3/28; G01J2003/283; G01J2003/284; G01N21/35; G01N21/3504
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
207 words
A spectroscopic analyzer for analysis of process streams, said analyzer comprising: an infrared light source; a sample cell having inlet and outlet openings for passage of a sample therethrough; means for directing infrared light from said infrared light source through said sample cell, said detector having an output signal proportional to the intensity of light intercepted by said detector; a rotatable circular variable filter positioned between said sample cell and said detector, the wavelength being passed by said filter being dependent upon the angular position of said filter; a synchronous motor mechanically coupled to rotate said circular variable filter; a pulse generator mechanically coupled to said circular variable filter, said generator generating pulses corresponding to the angular position of said filter, said generator further generating a synchronization pulse for each complete revolution of said filter, said pulses and said synchronization pulse being transmitted to a digital computer; means for amplifying and subsequently rectifying said output signal from said detector; and a digital computer, said computer being coupled to said pulse generator and programmed to control the preselected wavelengths at which data is taken, said computer being further programmed to read and store said rectified signal and print out concentrations of components having absorption at said preselected wavelengths.
Claim 2
Dependent Claim
207 words
A spectroscopic analyzer for analysis of process streams, said analyzer comprising: an infrared light source; a sample cell having inlet and outlet openings for passage of a sample therethrough; means for directing infrared light from said infrared light source through said sample cell, said detector having an output signal proportional to the intensity of light intercepted by said detector; a rotatable circular variable filter positioned between said sample cell and said detector, the wavelength being passed by said filter being dependent upon the angular position of said filter; a synchronous motor mechanically coupled to rotate said circular variable filter; a pulse generator mechanically coupled to said circular variable filter, said generator generating pulses corresponding to the angular position of said filter, said generator further generating a synchronization pulse for each complete revolution of said filter, said pulses and said synchronization pulse being transmitted to a digital computer; means for amplifying and subsequently rectifying said output signal from said detector; and a digital computer, said computer being coupled to said pulse generator and programmed to control the preselected wavelengths at which data is taken, said computer being further programmed to read and store said rectified signal and print out concentrations of components having absorption at said preselected wavelengths.
Claim 3
Dependent Claim
54 words
The analyzer of claim 1 wherein said digital computer is provided with a position interrupt counter, said counter being adapted to sum pulses generated by said generator, said computer being programmed to continuously monitor said counter, said computer being further programmed to reset said counter when said synchronization pulse is generated by said generator.
Claim 4
Dependent Claim
20 words
The analyzer of claim 1 wherein said pulse generator generates 5,000 position pulses per revolution of said circular variable filter.
Claim 5
Dependent Claim
79 words
The analyzer of claim 1 further including: a reference infrared light beam; an optical wedge; an optical servo motor connected to said optical wedge and adapted to insert said optical wedge in said reference beam to correct for absorption of said sample by infrared light passing therethrough; and a re-transmitting slide wire suitably connected to said optical servo motor, said re-transmitting slide wire transmitting a voltage to the digital computer corresponding to analytical absorption at each preselected analytical frequency.
Claim 6
Independent Claim
105 words
A method of continuously analyzing process streams having at least one component of interest using a chopped infrared light source and infrared detector, said method comprising the steps of: rotating a circular variable filter at a constant speed; generating a plurality of pulses corresponding to the angular position of said circular variable filter; continuously counting said generated pulses by means of an interrupt counter until a count corresponding to a predetermined angular position of said circular variable filter is reached; and recording a signal generated by said infrared detector, said signal being related to a wavelength of light being passed by said circular variable filter.
Claim 7
Independent Claim
105 words
A method of continuously analyzing process streams having at least one component of interest using a chopped infrared light source and infrared detector, said method comprising the steps of: rotating a circular variable filter at a constant speed; generating a plurality of pulses corresponding to the angular position of said circular variable filter; continuously counting said generated pulses by means of an interrupt counter until a count corresponding to a predetermined angular position of said circular variable filter is reached; and recording a signal generated by said infrared detector, said signal being related to a wavelength of light being passed by said circular variable filter.
Claim 8
Dependent Claim
29 words
The method of claim 5 further including the step of generating a synchronizing pulse, said synchronizing pulse resetting said interrupt counter to zero whereby said analyzing process is repeated.
Claim 9
Dependent Claim
22 words
The method of claim 5 wherein said signal is recorded by a digital computer and subsequently analyzed using a predetermined calibration matrix.
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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) | 1977-02-25 | 1977-08-27 | 1978-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-25 | 1981-08-27 | 1982-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-25 | 1985-08-27 | 1986-02-26 | $7700.00 | Window Closed / Lapsed |