US3726271A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Spirometer with automatic electronic zeroing circuit
Assignee: SENSORMEDICS Corp A CORP OF
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Filing: 1970-07-02
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Granted: 1973-04-10
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Expires: 1990-07-02
Abstract
Abstract A pulmonary function measuring system incorporating an automatic electronic zeroing circuit to provide accurate pulmonary measurements irrespective of any initial offset value. The system eliminates tedious and inaccurate manual calibration and is adapted for use in air volume, pressure and flow measurements such as in spirometric-plethysmographic systems.
Inventors
- 👤 W Mondshine
- 👤 C Bishop
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 06:22
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/08; A61B5/0806; A61B5/085; A61B5/087
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
209 words
A device for measuring respiratory resistance of a respiratory system comprising: a. a tube for connection to said respiratory system, b. means for impressing forced oscillatory air movement into said tube, c. transducer means connected to said tube for measuring the pressure and flow of oscillatory air movement in the tube and for generating first and second electrical signals, respectively indicative of said pressure and flow, said signals having a possible initial offset value, d. switch-controlled automatic zeroing circuit means for receiving said first and second electrical signals and for generating third and fourth electrical signals compensated for the initial offset value, e. slope-sensing means for receiving said first and second electrical signals, and for detecting, by changes in slope, when said signals reach maxima and minima values, said slope sensing means adapted to actuate said switch-controlled automatic zeroing circuit means upon detecting a maximum value and to deactuate said switch-controlled automatic zeroing circuit means upon detecting a minimum value, f. peak detector means connected to receive said third and fourth compensated electrical signals for generating fifth and sixth electrical signals indicative of the peak-to-peak values of said third and fourth compensated electrical signals, and g. computin means responsive to said fifth and sixth signals for calculating respiratory resistance.
Claim 2
Independent Claim
209 words
A device for measuring respiratory resistance of a respiratory system comprising: a. a tube for connection to said respiratory system, b. means for impressing forced oscillatory air movement into said tube, c. transducer means connected to said tube for measuring the pressure and flow of oscillatory air movement in the tube and for generating first and second electrical signals, respectively indicative of said pressure and flow, said signals having a possible initial offset value, d. switch-controlled automatic zeroing circuit means for receiving said first and second electrical signals and for generating third and fourth electrical signals compensated for the initial offset value, e. slope-sensing means for receiving said first and second electrical signals, and for detecting, by changes in slope, when said signals reach maxima and minima values, said slope sensing means adapted to actuate said switch-controlled automatic zeroing circuit means upon detecting a maximum value and to deactuate said switch-controlled automatic zeroing circuit means upon detecting a minimum value, f. peak detector means connected to receive said third and fourth compensated electrical signals for generating fifth and sixth electrical signals indicative of the peak-to-peak values of said third and fourth compensated electrical signals, and g. computin means responsive to said fifth and sixth signals for calculating respiratory resistance.
Claim 3
Dependent Claim
166 words
A device for measuring respiratory resistance of a respiratory system as recited in claim 1 wherein said switch-controlled automatic zeroing circuit means comprises: a. a differential amplifier having an inverting input terminal, a non-inverting input terminal, and an output terminal; b. a feedback circuit including an operational amplifier having an input connection point and an output connection point and further including a capacitor connected between said input connection point and said output connection point, said operational amplifier and said capacitor functioning as an integrator, said output connection point being electrically connected to said non-inverting input terminal; and c. switch means for selectively, electrically connecting and disconnecting said output terminal and said input connection point for causing said integrator to zero said differential amplifier in order to compensate said initial offset value on said inverting input terminal when said switch means is in its connecting mode and in order to hold the compensation for said initial offset value when said switch means is in its disconnecting mode.
Claim 4
Dependent Claim
30 words
A device for measuring respiratory resistance of a respiratory system as recited in claim 1, further comprising indication means connected to said computing means for indicating the calculated respiratory resistance.
Claim 5
Dependent Claim
22 words
A device for measuring respiratory resistance of a respiratory system as recited in claim 3, wherein said indication means comprises a meter.
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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) | 1976-04-09 | 1976-10-09 | 1977-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-09 | 1980-10-09 | 1981-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-09 | 1984-10-09 | 1985-04-10 | $7700.00 | Window Closed / Lapsed |