US4760732A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Flow programmer for gas chromatography
Assignee: Dow Chemical Co
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Filing: 1987-06-29
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Granted: 1988-08-02
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Expires: 2007-06-29
Abstract
Abstract A flow programmer for gas chromatography of the type having a mass flow meter for controlling the flow rate of a gas chromatography carrier gas controllable at a selected carrier gas flow rate program by an electrical input to the mass flow meter and an electrical circuit for generating the electrical input. The improvement is that the electrical circuit for generating the electrical input is an analog electrical circuit which includes an operational amplifier having an electrical capacitor in the feedback loop of the operational amplifier to produce a selected voltage input program.
Inventors
- 👤 Robert A. Bredeweg
- 👤 Jeffrey R. Larson
- 👤 Stephen W. Barr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 06:41
CPC Classifications
G; G01; G01N; G01N30/00; G01N30/02; G01N30/26; G01N30/28; G01N30/32
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
101 words
In an improved flow programmer for gas chromatography comprising means for controlling the flow rate of a gas chromatography carrier gas controllable at a selected carrier gas flow rate program by an electrical input thereto and a means for generating the electrical input, the means for controlling the flow rate of a gas chromatography carrier gas incorporating a mass flow meter, wherein the improvement comprises: that the means for generating the electrical input consists essentially of an analog electrical circuit which produces a selected voltage input program, the circuit comprising at least one operational amplifier and at least one electrical capacitor.
Claim 2
Dependent Claim
101 words
In an improved flow programmer for gas chromatography comprising means for controlling the flow rate of a gas chromatography carrier gas controllable at a selected carrier gas flow rate program by an electrical input thereto and a means for generating the electrical input, the means for controlling the flow rate of a gas chromatography carrier gas incorporating a mass flow meter, wherein the improvement comprises: that the means for generating the electrical input consists essentially of an analog electrical circuit which produces a selected voltage input program, the circuit comprising at least one operational amplifier and at least one electrical capacitor.
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) | 1991-08-02 | 1992-02-01 | 1992-08-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-02 | 1996-02-01 | 1996-08-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-02 | 2000-02-01 | 2000-08-02 | $7700.00 | Window Closed / Lapsed |