US3698237A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Memory circuit for chromatographs
Assignee: Sunoco Inc
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Filing: 1970-11-20
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Granted: 1972-10-17
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Expires: 1990-11-20
Abstract
Abstract A solid-state circuit useful with a two-component vapor phase chromatograph provides and stores a voltage representative of one of the two chromatograph peaks, and, in addition, obtains and stores a voltage representative of the ratio between the two peaks. The circuit includes an arrangement for limiting the ratio to some adjustable value, which enables the full scale of the recorder to be utilized.
Inventors
- 👤 Charles F Rhodes Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 23:03
CPC Classifications
G; G01; G01N; G01N30/00; G01N30/02; G01N30/86; G01N30/8624; H; H03; H03K; H03K5/00; H03K5/22; H03K5/24
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
176 words
In a two-component chromatograph including a recorder whose pen is driven in accordance with first and second detected peaks eluting at different, known times from a chromatographic column: means for developing and storing a voltage representative of said first peak, a variable resistor so coupled to the recorder pen drive mechanism that the resistance thereof is proportional to said second peak, means for applying said voltage to one end of said resistor, an operational amplifier, switching means which when closed connects the other end of said resistor to the input of said amplifier, means operating upon the recorder pen reaching the summit of said second peak for actuating said switching means to its closed position, and a feedback circuit around said amplifier including a series resistor connected to the amplifier input, said circuit comprising means operating concomitantly with the closing of said switching means for producing a flow of current through said series resistor equal to the current flowing through said variable resistor at its resistance value which corresponds to the summit of said second peak.
Claim 2
Dependent Claim
176 words
In a two-component chromatograph including a recorder whose pen is driven in accordance with first and second detected peaks eluting at different, known times from a chromatographic column: means for developing and storing a voltage representative of said first peak, a variable resistor so coupled to the recorder pen drive mechanism that the resistance thereof is proportional to said second peak, means for applying said voltage to one end of said resistor, an operational amplifier, switching means which when closed connects the other end of said resistor to the input of said amplifier, means operating upon the recorder pen reaching the summit of said second peak for actuating said switching means to its closed position, and a feedback circuit around said amplifier including a series resistor connected to the amplifier input, said circuit comprising means operating concomitantly with the closing of said switching means for producing a flow of current through said series resistor equal to the current flowing through said variable resistor at its resistance value which corresponds to the summit of said second peak.
Claim 3
Dependent Claim
30 words
Apparatus defined in claim 1, wherein said switching means is voltage-actuated, and wherein said means operating upon said recorder pen produces a voltage upon the recorder pen reaching said summit.
Claim 4
Dependent Claim
45 words
Apparatus according to claim 2, wherein said feedback circuit connected between the output and the input of said amplifier also comprises a voltage-actuated switch in series in said circuit, and means for utilizing said produced voltage to actuate said last-mentioned switch to its closed position.
Claim 5
Dependent Claim
79 words
Apparatus defined in claim 1, wherein the first-mentioned means comprises means coupled to the recorder pen drive mechanism for developing a voltage representative of the first peak, an operational amplifier receptive of said voltage, a storage capacitor, a second switching means acting when closed to couple the output of said last-mentioned amplifier to said capacitor, and means operating upon the recorder pen reaching the summit of said first peak for actuating said second switching means to its closed position.
Claim 6
Dependent Claim
40 words
Apparatus defined in claim 4, wherein said second switching means is voltage-actuated, and wherein the means which actuates said second switching means to its closed position produces a voltage upon the recorder pen reaching the summit of said first peak.
Claim 7
Dependent Claim
42 words
Apparatus defined in claim 5, wherein said first recited switching means is voltage-actuated, and wherein the means which actuates said first recited switching means to its closed position produces a voltage upon the recorder pen reaching the summit of said second peak.
Claim 8
Dependent Claim
22 words
Apparatus according to claim 1, including also means for limiting the voltage output of said operational amplifier to a definite maximum value.
Claim 9
Dependent Claim
30 words
Apparatus defined in claim 7, wherein the means for limiting comprises a negative feedback arrangement with an adjustable threshold coupled between the oUtput and the input of said operational amplifier.
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) | 1975-10-17 | 1976-04-17 | 1976-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-17 | 1980-04-17 | 1980-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-17 | 1984-04-17 | 1984-10-17 | $7700.00 | Window Closed / Lapsed |