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Patent US4674336A successfully refreshed from Google Patents.
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US4674336A Expired / Lapsed US ⏱️ 0.0 years remaining

Volumetric flow rate determination in conduits not directly accessible

Assignee: KOMEG KONTROLL-UND AUTOMATIONSTECHNIK GmbH
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Filing: 1985-10-25
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Granted: 1987-06-23
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Expires: 2005-10-25
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Abstract

Abstract A catheter, particularly adapted for cardiac output determination, comprises an elongated tube of flexible material, the tube having a substantially rigid distal portion on which is disposed an ultrasonic transducer and a proximate, inflatable balloon. The ultrasonic transducer is arranged so as to direct a beam of ultrasound toward a transverse plane that bisects the balloon, and is connected by appropriate leads to a conventional Doppler circuit. With the balloon deflated, the signal from the Doppler circuit is sensed to measure blood velocity. Thereafter, the balloon is inflated so that it has a predetermined cross-sectional area in the transverse plane. The signal from the Doppler circuit is again sensed to measure blood velocity. Using a simple mathematical relationship, the effective internal cross-sectional area of the blood vessel is determined from the two measured velocities and from the predetermined cross-sectional area of the balloon when inflated. The volumetric flow rate is then determined by multiplying the first measured velocity by the effective internal cross-sectional area.

Inventors

  • 👤 G. Gilbert Johnston

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-23 04:17
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/66; G01F1/663; A; A61; A61B; A61B8/00; A61B8/06; A61B8/12; A61B8/44; A61B8/4444; A61B8/445

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 127 words
A method for determining the volumetric flow rate of a fluid in a conduit whose effective internal cross-sectional area is unknown, comprising the steps of: measuring, by the use of ultrasonic energy, the unrestricted velocity of the fluid at points where it passes through an imaginary plane transverse to the conduit; introducing a flow restriction into the conduit, said flow restriction having a predetermined cross-sectional area in said imaginary plane; measuring, by the use of ultrasonic energy, the restricted velocity of the fluid at points where it passes through said imaginary plane; determining said effective internal cross-sectional area from said unrestricted velocity, said restricted velocity, and said predetermined cross-sectional area; and, determining said volumetric flow rate from said unrestricted velocity and said determined effective internal cross-sectional area.
Claim 2
Independent Claim 127 words
A method for determining the volumetric flow rate of a fluid in a conduit whose effective internal cross-sectional area is unknown, comprising the steps of: measuring, by the use of ultrasonic energy, the unrestricted velocity of the fluid at points where it passes through an imaginary plane transverse to the conduit; introducing a flow restriction into the conduit, said flow restriction having a predetermined cross-sectional area in said imaginary plane; measuring, by the use of ultrasonic energy, the restricted velocity of the fluid at points where it passes through said imaginary plane; determining said effective internal cross-sectional area from said unrestricted velocity, said restricted velocity, and said predetermined cross-sectional area; and, determining said volumetric flow rate from said unrestricted velocity and said determined effective internal cross-sectional area.
Claim 3
Independent Claim 101 words
A method for determining the effective internal cross-sectional area of a conduit, comprising the steps of: measuring, by the use of ultrasonic energy, the unrestricted velocity of fluid at points where it passes through an imaginary plane transverse to the conduit; introducing a flow restriction into the conduit, said flow restriction having a predetermined cross-sectional area in said imaginary plane; measuring, by the use of ultrasonic energy, the restricted velocity of the fluid at points where it passes through said imaginary plane; and, determining said effective internal cross-sectional area from said unrestricted velocity, said restricted velocity, and said predetermined cross-sectional area.
Claim 4
Independent Claim 101 words
A method for determining the effective internal cross-sectional area of a conduit, comprising the steps of: measuring, by the use of ultrasonic energy, the unrestricted velocity of fluid at points where it passes through an imaginary plane transverse to the conduit; introducing a flow restriction into the conduit, said flow restriction having a predetermined cross-sectional area in said imaginary plane; measuring, by the use of ultrasonic energy, the restricted velocity of the fluid at points where it passes through said imaginary plane; and, determining said effective internal cross-sectional area from said unrestricted velocity, said restricted velocity, and said predetermined cross-sectional area.

References Cited (Backward Citations)

US4142412A Cited
US4574617A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1990-06-22 1990-12-22 1991-06-23 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1994-06-22 1994-12-22 1995-06-23 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1998-06-22 1998-12-22 1999-06-23 $7700.00 Window Closed / Lapsed

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