US3896788A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Doppler effect blood flow meter
Assignee: Hitachi Healthcare Manufacturing Ltd
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Filing: 1973-12-28
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Granted: 1975-07-29
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Expires: 1993-12-28
Abstract
Abstract A Doppler effect blood flow meter. The flow meter has dual filters having a sharp filtering property capable of dividing ultrasonic waves reflected from blood corpuscles into frequency groups above and below ultrasonic waves emitted by a probe in the blood vessels thereby detecting the blood velocity and the blood flow and detecting the direction of the blood flow based on the theory of the Doppler effect.
Inventors
- 👤 Yutaka Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 01:08
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/66; G01F1/663; A; A61; A61B; A61B8/00; A61B8/06; G01P; G01P5/00; G01P5/24; G01P5/241; G01P5/242; G01S; G01S15/00; G01S15/02; G01S15/50; G01S15/58; G01S15/586
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
157 words
An improved Doppler effect blood flow meter for determining velocity and blood flow direction comprising a high frequency oscillator which generates a high frequency signal, a probe means coupled to said high frequency oscillator for transmitting the high frequency signal toward blood vessels and for receiving said high frequency signal after reflection thereof by blood corpuscles, said received signal being Doppler shifted in frequency, two filter means operatively coupled in parallel to said probe means, said filter means having sharp filtering characteristics capable, respectively, of dividing the high frequency waves reflected from blood corpuscles into frequency ranges above and below the frequency of said transmitted signal, indicative of blood flow toward and away from said probe means, means operatively coupled to each said filter means for producing an output wave indicative of the frequency of the received signal, and output means coupled to said output wave producing means for indicating the velocity and direction of blood flow.
Claim 2
Dependent Claim
157 words
An improved Doppler effect blood flow meter for determining velocity and blood flow direction comprising a high frequency oscillator which generates a high frequency signal, a probe means coupled to said high frequency oscillator for transmitting the high frequency signal toward blood vessels and for receiving said high frequency signal after reflection thereof by blood corpuscles, said received signal being Doppler shifted in frequency, two filter means operatively coupled in parallel to said probe means, said filter means having sharp filtering characteristics capable, respectively, of dividing the high frequency waves reflected from blood corpuscles into frequency ranges above and below the frequency of said transmitted signal, indicative of blood flow toward and away from said probe means, means operatively coupled to each said filter means for producing an output wave indicative of the frequency of the received signal, and output means coupled to said output wave producing means for indicating the velocity and direction of blood flow.
Claim 3
Dependent Claim
19 words
The device of claim 1 further comprising an amplifier interposed between said probe means and said parallel filter means.
Claim 4
Dependent Claim
60 words
The device of claim 2 wherein each said output wave producing means is comprised of an amplitude detector coupled to one of said filter means, a frequency detecting means coupled to said amplitude detector and producing frequency pulses, and means coupled to said frequency detecting means for converting the output of said frequency detecting means into a direct current voltage.
Claim 5
Dependent Claim
92 words
The device of claim 3 wherein said output means is comprised of a plurality of indicators, one coupled to each converting means for indicating velocity and direction of blood flow in one of a direction approaching and withdrawing from said probe means, depending on the associated filter means, a differential amplifier coupled to the output of said at least two converting means, and an indicator coupled to the output of said differential amplifier, whereby the last-noted indicator will produce an accurate output when blood flows in one direction or in opposite directions.
Claim 6
Dependent Claim
18 words
The device of claim 4 further comprising integrating means interposed between each converting means and said output means.
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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) | 1978-07-28 | 1979-01-27 | 1979-07-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-28 | 1983-01-27 | 1983-07-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-28 | 1987-01-27 | 1987-07-29 | $7700.00 | Window Closed / Lapsed |