Patent US3714813A successfully refreshed from Google Patents.
US3714813A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for stabilizing component elution times in gas chromatographs
Assignee: Dow Chemical Co
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Filing: 1971-01-12
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Granted: 1973-02-06
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Expires: 1991-01-12
Abstract
Abstract A peak stabilizer in accordance with this invention controls the peak retention time during an analysis, by gas chromatograph, for example, so that this time will be the same for all determinations. This allows a peak to be gated or picked for process control or read-out without the undesirable possibility that it would drift beyond the time limits of the gate. If a peak in the chromatogram, for example, is sampled on the leading and trailing slopes at predetermined times, a comparison of these voltages will indicate if the peak is early, late or at its right time. The carrier gas flow or other rate control parameter may be automatically changed to bring the peak back to the proper retention time.
Inventors
- 👤 F Martin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 05:55
CPC Classifications
G; G01; G01N; G01N30/00; G01N30/02; G01N30/86; G01N30/8624; G01N30/8665; G01N30/8668; G06; G06G; G06G7/00; G06G7/48; G06G7/75; G01N30/8627
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
114 words
A system for stabilizing the peak retention time in fluid chromatographs, comprising means including a capacitor and an amplifier for sequentially measuring and storing amplitude values at points along opposite slopes of a selected peak signal, signal comparison amplifier means for providing an output signal which is a function in amplitude and polarity of the difference between said stored values, means for applying said output signal to polarity and amplitude sensitive switching means, said switching means coupling a power source to reversible motor drive means, said drive means being coupled to a valve for controlling the flow of carrier fluid to said chromatograph as a function of the polarity and amplitude of said signal.
Claim 2
Independent Claim
114 words
A system for stabilizing the peak retention time in fluid chromatographs, comprising means including a capacitor and an amplifier for sequentially measuring and storing amplitude values at points along opposite slopes of a selected peak signal, signal comparison amplifier means for providing an output signal which is a function in amplitude and polarity of the difference between said stored values, means for applying said output signal to polarity and amplitude sensitive switching means, said switching means coupling a power source to reversible motor drive means, said drive means being coupled to a valve for controlling the flow of carrier fluid to said chromatograph as a function of the polarity and amplitude of said signal.
Claim 3
Independent Claim
114 words
A system for stabilizing the peak retention time in fluid chromatographs, comprising means including a capacitor and an amplifier for sequentially measuring and storing amplitude values at points along opposite slopes of a selected peak signal, signal comparison amplifier means for providing an output signal which is a function in amplitude and polarity of the difference between said stored values, means for applying said output signal to polarity and amplitude sensitive switching means, said switching means coupling a power source to reversible motor drive means, said drive means being coupled to a valve for controlling the flow of carrier fluid to said chromatograph as a function of the polarity and amplitude of said signal.
Claim 4
Independent Claim
114 words
A system for stabilizing the peak retention time in fluid chromatographs, comprising means including a capacitor and an amplifier for sequentially measuring and storing amplitude values at points along opposite slopes of a selected peak signal, signal comparison amplifier means for providing an output signal which is a function in amplitude and polarity of the difference between said stored values, means for applying said output signal to polarity and amplitude sensitive switching means, said switching means coupling a power source to reversible motor drive means, said drive means being coupled to a valve for controlling the flow of carrier fluid to said chromatograph as a function of the polarity and amplitude of said signal.
Claim 5
Dependent Claim
22 words
A system in accordance with claim 1, wherein timer means controls the time interval during which said drive means may be actuated.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-06 | 1976-08-07 | 1977-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-06 | 1980-08-07 | 1981-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-06 | 1984-08-07 | 1985-02-06 | $7700.00 | Window Closed / Lapsed |