US3690143A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self calibrating tidal volume impedance pneumograph
Assignee: American Optical Corp
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Filing: 1970-11-27
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Granted: 1972-09-12
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Expires: 1990-11-27
Abstract
Abstract A method of automatically calibrating an electronic respiration monitoring system including a pneumograph responsive to changes in thoracic inpedance of a breathing patient for providing an analog signal proportional to breath volume and a volumecalibrated inflatable bag. The method comprises the steps of: (a) operatively associating the pneumograph with the thorax of the patient; (b) positioning said bag in association with the patient with the bag being arranged to capture gases exhaled by the patient; (c) determining maximum filling of said bag; and (d) automatically calibrating said system upon the filling of the bag.
Inventors
- 👤 Christopher C Day
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:04
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/08; A61B5/091; A61B5/085; A61B5/086
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
95 words
A method of automatically calibrating an electronic respiration monitoring system including (1) impedance means responsive to changes in thoracic impedance of a breathing patient for providing an analog signal proportional to breath volume and (2) a volume-calibrated inflatable bag, said method comprising the steps of: a. operatively associating said impedance means with the thorax of said patient; b. positioning said bag in association with said patient, said bag arranged to capture gases exhaled by said patient; c. determining maximum filling of said bag; and, d. automatically calibrating said system upon the filling of said bag.
Claim 2
Independent Claim
95 words
A method of automatically calibrating an electronic respiration monitoring system including (1) impedance means responsive to changes in thoracic impedance of a breathing patient for providing an analog signal proportional to breath volume and (2) a volume-calibrated inflatable bag, said method comprising the steps of: a. operatively associating said impedance means with the thorax of said patient; b. positioning said bag in association with said patient, said bag arranged to capture gases exhaled by said patient; c. determining maximum filling of said bag; and, d. automatically calibrating said system upon the filling of said bag.
Claim 3
Dependent Claim
168 words
A method as recited in claim 1 and wherein said system is arranged to measure tidal volume of respiration, said method further comprising the steps of: e. activating a calibration switch to concurrently obtain zero system gain, discharge residual voltage from a second capacitor, and enable two gates; f. charging a first capacitor by said analog signal during exhalation into said bag; g. obtaining a trigger signal upon inflation of said bag to its maximum volume; h. passing said trigger signal through one of said gates; i. stopping the charging of said first capacitor in response to said trigger signal; j. holding steady the voltage of said charGed first capacitor as a calibration voltage; k. transferring said calibration voltage from said first capacitor to said second capacitor during inhalation to obtain a transferred calibration voltage; l. said transferred voltage activating a servo loop through the other of said gates to obtain calibrated gain; and, m. disabling both of said gates to ready said system for tidal volume measurement.
Claim 4
Dependent Claim
70 words
A method as recited in claim 2 and wherein the step of activating said servo loop further comprises: n. activating a motor in response to said transferred calibration voltage; o. driving a potentiometer wiper by said motor to obtain a feedback voltage; p. subtracting a reference voltage from said feedback voltage to obtain an error voltage; and, q. applying said error voltage to said motor to position said potentiometer wiper.
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) | 1975-09-12 | 1976-03-13 | 1976-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-12 | 1980-03-13 | 1980-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-12 | 1984-03-13 | 1984-09-12 | $7700.00 | Window Closed / Lapsed |