US3848591A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronically-controlled gas pressure meter
Assignee: US Philips Corp
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Filing: 1972-10-13
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Granted: 1974-11-19
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Expires: 1992-10-13
Abstract
Abstract Apparatus for monitoring lung gas pressure includes a pressure transducer that controls the frequency of a variable oscillator as a function of the gas pressure. The frequency signal is converted into a proportional analog signal which in turn is integrated to provide an output signal indicative of the mean value of the gas pressure. An indicator responds to the output signal to provide an indication of the mean gas pressure.
Inventors
- 👤 G Smythe
- 👤 G Orton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:47
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/103; A61B5/11; A61B5/113; A61M; A61M16/00; A61M16/0051; A61M16/021; G; G01; G01L; G01L23/00; G01L23/08; G01L23/12; G01L23/125; G01L9/00; G01L9/0082; G01L9/0086; G01L9/12; G01L9/125; A61B5/72; A61B5/7235; A61B5/7242; A61M16/0003; A61M16/0009
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
165 words
A gas pressure meter suitable for monitoring the gas pressure in a patient''s lungs during ventilation of the patient by means of a medical respirator comprising, a pressure transducer for converting said gas pressure into an equivalent electric parameter, a gas tube coupled thereto, a first oscillator which is connected to the transducer so that the oscillation frequency thereof depends upon the instantaneous value of the transducer output, a second oscillator of fixed frequency, mixer circuit means coupled to said first and second oscillators to derive an output signal having a frequency which is equal to the difference frequency of the oscillator frequencies, a frequency-to analogue converter coupled to the mixer output for providing an analogue signal proportional to the difference frequency, an integrator, means for applying said analogue signal to the integrator which provides an output signal indicative of the mean value of the gas pressure, and visual pressure indicator means for providing an indication of the analogue signal and of said output signal.
Claim 2
Dependent Claim
165 words
A gas pressure meter suitable for monitoring the gas pressure in a patient''s lungs during ventilation of the patient by means of a medical respirator comprising, a pressure transducer for converting said gas pressure into an equivalent electric parameter, a gas tube coupled thereto, a first oscillator which is connected to the transducer so that the oscillation frequency thereof depends upon the instantaneous value of the transducer output, a second oscillator of fixed frequency, mixer circuit means coupled to said first and second oscillators to derive an output signal having a frequency which is equal to the difference frequency of the oscillator frequencies, a frequency-to analogue converter coupled to the mixer output for providing an analogue signal proportional to the difference frequency, an integrator, means for applying said analogue signal to the integrator which provides an output signal indicative of the mean value of the gas pressure, and visual pressure indicator means for providing an indication of the analogue signal and of said output signal.
Claim 3
Dependent Claim
67 words
A pressure meter as claimed in claim 1 wherein the pressure transducer comprises a pressure-sensitive capacitor which comprises a metal aneroid capsule which has a part which is movable as a function of the gas pressure prevailing in it and forms a first conductive plate of the capacitor, and a second conductive capacitor plate which is fixedly arranged externally of the capsule and opposite the movable plate.
Claim 4
Dependent Claim
86 words
A pressure meter as claimed in claim 1, further comprising first and second comparators connected to the output of the integrator, means for supplying to said first and second comparators first and second reference signals, respectively, that indicate the maximum and minimum safe values of lung gas pressure, respectively, alarm circuit means, and means connecting the output terminals of said comparators to said alarm circuit for giving an alarm signal when the value of the output signal from the integrator becomes too low or too high.
Claim 5
Dependent Claim
46 words
A pressure meter as claimed in claim 1 further comprising linearizing correction circuit means coupled between the output of the converter and the input to the integrator for linearizing the variation of said analogue signal as a function of the gas pressure applied to the transducer.
Claim 6
Dependent Claim
45 words
A pressure meter as claimed in claim 1 wherein the pressure transducer comprises a pressure-sensitive capacitor which converts a variation in gas pressure into a proportional variation in capacitance, the capacitance of said capacitor being operative to control the oscillation frequency of the first oscillator.
Claim 7
Independent Claim
160 words
A device for measuring the gas pressure in a respiratory system under control of a respirator comprising, ventilation means for forcing gas into and out of said respiratory system, a pressure transducer for converting gas pressure into a proportional electric parameter, a tube coupling the pressure transducer to said respiratory system via the ventilation means, a first oscillator, means connecting the transducer to said first oscillator so that the electric parameter variations of the transducer control the oscillator oscillation frequency, a second fixed frequency oscillator, mixer circuit means coupled to said first and second oscillators to derive an output signal of a frequency equal to the difference frequency of the oscillator frequencies, a frequency-to analogue signal proportional to the difference frequency, an integrator, means for applying said analogue signal to the integrator which provides an output signal indicative of the mean value of the gas pressure, and visual pressure indicator means for providing an indication of said integrator output signal.
Claim 8
Independent Claim
160 words
A device for measuring the gas pressure in a respiratory system under control of a respirator comprising, ventilation means for forcing gas into and out of said respiratory system, a pressure transducer for converting gas pressure into a proportional electric parameter, a tube coupling the pressure transducer to said respiratory system via the ventilation means, a first oscillator, means connecting the transducer to said first oscillator so that the electric parameter variations of the transducer control the oscillator oscillation frequency, a second fixed frequency oscillator, mixer circuit means coupled to said first and second oscillators to derive an output signal of a frequency equal to the difference frequency of the oscillator frequencies, a frequency-to analogue signal proportional to the difference frequency, an integrator, means for applying said analogue signal to the integrator which provides an output signal indicative of the mean value of the gas pressure, and visual pressure indicator means for providing an indication of said integrator output signal.
Claim 9
Dependent Claim
67 words
A device as claimed in claim 6 wherein the pressure transducer comprises a pressure-sensitive capacitor for converting a variation in gas pressure into a variation in capacitance, said device further comprising linearizing correction circuit means coupled between the output of the converter and the input to the integrator for linearizing the variation of said analogue signal as a function of the gas pressure applied to the transducer.
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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) | 1977-11-18 | 1978-05-20 | 1978-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-18 | 1982-05-20 | 1982-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-18 | 1986-05-20 | 1986-11-19 | $7700.00 | Window Closed / Lapsed |