Patent US3595079A successfully refreshed from Google Patents.
US3595079A
Expired / Lapsed
US
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Fluid flow velocity measuring apparatus
Assignee: Northwestern University
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Filing: 1967-11-13
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Granted: 1971-07-27
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Expires: 1987-11-13
Abstract
Abstract Apparatus for measuring instantaneous fluid flow velocity including a probe having fluid flow velocity, temperature and direction sensor thermistors selectively positioned thereon. The sensor thermistors are connected in an electrical circuit including bridge circuits adapted to compensate for changes in temperature of the fluid being measured. The circuit establishes an output signal proportional to the flow velocity of the fluid and having a polarity dependent upon the direction of fluid flow. The circuit further computes the acceleration, mean velocity and peak velocity of fluid flow. The measuring apparatus is calibrated by a calibrator having a piston-cylinder arrangement adapted to effect predetermined fluid flow through a flow conduit which supports the probe such that its sensor thermistors are disposed within the flow stream. The calibrator includes a potentiometer circuit operative to establish an electrical signal proportional to the velocity of fluid flow past the probe sensors. The output signal of the measuring apparatus may then be compared to the signal produced by the calibrator potentiometer circuit and the measuring apparatus adjusted to bring the signals into desired phase and magnitude relation.
Inventors
- 👤 Allen R Grahn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:33
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/68; G01F1/684; A; A61; A61B; A61B5/00; A61B5/02; A61B5/026; A61B5/0275; A61B5/028
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
268 words
Apparatus for measuring instantaneous fluid flow velocity comprising, in combination, a probe having an elongated tubular body and an end portion adapted to be inserted into a fluid flow conduit, said end portion having a first opening, said tubular body defining a longitudinally extending passage therethrough intersecting said first opening, said probe body further having a second opening in the peripheral surface thereof axially spaced from said first opening and intersecting said passage, senSor means including fluid flow velocity, temperature and direction sensor thermistors supported by said probe for insertion into the fluid flow conduit to sense the velocity, temperature and direction of the fluid flow being measured, and circuit means associated with said sensor means and adapted to produce a continuously temperature compensated velocity output signal proportional to the flow velocity of the fluid being measured, said circuit means including amplifier means adapted to directly and continuously maintain said velocity sensor at a predetermined temperature differential relative to the temperature of the fluid being measured, said circuit means being further adapted to compute the electrical power required to maintain said velocity sensor at said predetermined temperature differential, said circuit means including means associated with said direction sensor thermistor to alter the polarity of said velocity output signal dependent on the direction of fluid flow being measured, said velocity sensor thermistor and said direction sensor thermistor being supported generally outwardly from said first opening and being connected to said circuit means through said first opening, and said temperature sensor means being supported generally adjacent said second opening and being connected to said circuit means through said second opening.
Claim 2
Dependent Claim
268 words
Apparatus for measuring instantaneous fluid flow velocity comprising, in combination, a probe having an elongated tubular body and an end portion adapted to be inserted into a fluid flow conduit, said end portion having a first opening, said tubular body defining a longitudinally extending passage therethrough intersecting said first opening, said probe body further having a second opening in the peripheral surface thereof axially spaced from said first opening and intersecting said passage, senSor means including fluid flow velocity, temperature and direction sensor thermistors supported by said probe for insertion into the fluid flow conduit to sense the velocity, temperature and direction of the fluid flow being measured, and circuit means associated with said sensor means and adapted to produce a continuously temperature compensated velocity output signal proportional to the flow velocity of the fluid being measured, said circuit means including amplifier means adapted to directly and continuously maintain said velocity sensor at a predetermined temperature differential relative to the temperature of the fluid being measured, said circuit means being further adapted to compute the electrical power required to maintain said velocity sensor at said predetermined temperature differential, said circuit means including means associated with said direction sensor thermistor to alter the polarity of said velocity output signal dependent on the direction of fluid flow being measured, said velocity sensor thermistor and said direction sensor thermistor being supported generally outwardly from said first opening and being connected to said circuit means through said first opening, and said temperature sensor means being supported generally adjacent said second opening and being connected to said circuit means through said second opening.
Claim 3
Dependent Claim
42 words
Apparatus according to claim 1 including means electrically insulating said thermistors from the fluid flow being measured, said insulating means serving to seal said longitudinally extending passage at said first and second openings so as to preclude the entry of fluid therein.
Claim 4
Dependent Claim
130 words
A probe for use in measuring instantaneous fluid flow velocity comprising a generally elongated tubular body member having at least one open end portion and defining a longitudinally extending passage intersecting said open end portion, electrical conductor means extending within said passage, fluid flow velocity sensor means supported by said body member outwardly from said open end portion and electrically connected to said conductor means, fluid flow temperature sensor means supported by said body in longitudinally spaced relation from said velocity sensor means and electrically connected to said conductor means, and means electrically insulating said velocity and temperature sensor means from the fluid flow being measured, said insulating means serving to seal said longitudinally extending passage at said open end portion so as to preclude the entry of fluid therein.
Claim 5
Dependent Claim
130 words
A probe for use in measuring instantaneous fluid flow velocity comprising a generally elongated tubular body member having at least one open end portion and defining a longitudinally extending passage intersecting said open end portion, electrical conductor means extending within said passage, fluid flow velocity sensor means supported by said body member outwardly from said open end portion and electrically connected to said conductor means, fluid flow temperature sensor means supported by said body in longitudinally spaced relation from said velocity sensor means and electrically connected to said conductor means, and means electrically insulating said velocity and temperature sensor means from the fluid flow being measured, said insulating means serving to seal said longitudinally extending passage at said open end portion so as to preclude the entry of fluid therein.
Claim 6
Dependent Claim
16 words
A probe as defined in claim 3 wherein said velocity and temperature sensor means comprise thermistors.
Claim 7
Dependent Claim
29 words
A probe as defined in claim 3 wherein each of said velocity and temperature sensor means comprises comprises a single thermistor having leads connected to said electrical conductor means.
Claim 8
Dependent Claim
62 words
A probe as defined in claim 5 wherein said elongated tubular body includes a second opening spaced longitudinally from said open end portion and communicating with said longitudinally extending passage, and wherein said temperature sensor thermistor is disposed within said second opening so as to lie generally in the plane of the peripheral surface of said body member adjacent said second opening.
Claim 9
Dependent Claim
38 words
A probe as defined in claim 3 including fluid flow direction sensor means supported by said body member in proximate relation to said velocity sensor means, said direction sensor means being being electrically connected to said conductor means.
Claim 10
Dependent Claim
39 words
A probe as defined in claim 7 wherein each of said direction, velocity and temperature sensor means comprises a single thermistor, and including means on said body member electrically insulating said direction sensor thermistor from the fluid being measured.
Claim 11
Dependent Claim
32 words
A probe as defined in claim 8 including means on said body member sealing said body member adjacent said second opening so as to prevent fluid from entering said longitudinally extending passage.
Claim 12
Dependent Claim
41 words
A probe as defined in claim 8 wherein said velocity sensor thermistOr is supported approximately 1 to 2 mm. outwardly from said body open end portion, and said direction sensor thermistor is supported less than 0.5 mm. from said velocity thermistor.
Claim 13
Dependent Claim
24 words
A probe as defined in claim 8 wherein said velocity, temperature and direction sensor thermistors are generally spherical having diameters of approximately 0.005 inch.
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) | 1974-07-26 | 1975-01-25 | 1975-07-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-26 | 1979-01-25 | 1979-07-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-26 | 1983-01-25 | 1983-07-27 | $7700.00 | Window Closed / Lapsed |