US3696673A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and means of measuring velocity fluctuations in unsteady flow
Assignee: University of Toronto
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Filing: 1968-04-01
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Granted: 1972-10-10
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Expires: 1988-04-01
Abstract
Abstract A gauge for measuring flow unsteadiness comprising a lift-sensor element having a lift-sensing surface to be presented to flow velocity disturbances perpendicular to a main stream flow to develop a time varying lift force with corresponding displacement responsive to time variations of the velocity disturbances, and means to translate the displacement variations into an alternating current to operate an indicator, and the method of measuring flow unsteadiness utilizing the principle of liftsensing to detect flow velocity disturbances.
Inventors
- 👤 Herbert S Ribner
- 👤 Thomas E Siddon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:12
CPC Classifications
G; G01; G01P; G01P5/00; G01P5/02; G01P5/04
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
142 words
A gauge for measuring the flow unsteadiness or the like comprising a rigidly supported unitary cantilever beam, liftsensor means rigidly direct coupled to said beam and presenting a surface to be exposed to flow velocity disturbances perpendicular to a main stream flow to develop time varying lifting forces on said cantilever beam to effect time varying beam displacements in response to rapid time variations in such velocity disturbances; means rigidly direct coupled to said beam to translate time varying beam displacements into an alternating current signal, and indicator means responsive to said alternating current signal, said beam being internally uninterrupted between the points of coupling of said direct coupled lift sensor and translating means and having a fundamental resonant frequency greater than the frequency of the time varying lift force corresponding to the highest frequency velocity disturbance time variation to be measured.
Claim 2
Dependent Claim
142 words
A gauge for measuring the flow unsteadiness or the like comprising a rigidly supported unitary cantilever beam, liftsensor means rigidly direct coupled to said beam and presenting a surface to be exposed to flow velocity disturbances perpendicular to a main stream flow to develop time varying lifting forces on said cantilever beam to effect time varying beam displacements in response to rapid time variations in such velocity disturbances; means rigidly direct coupled to said beam to translate time varying beam displacements into an alternating current signal, and indicator means responsive to said alternating current signal, said beam being internally uninterrupted between the points of coupling of said direct coupled lift sensor and translating means and having a fundamental resonant frequency greater than the frequency of the time varying lift force corresponding to the highest frequency velocity disturbance time variation to be measured.
Claim 3
Dependent Claim
35 words
A gauge as claimed in claim 1 in which said translating means comprises a transducer providing an alternating current signal in response to changes in beam displacement with time, while ignoring time independent beam displacement.
Claim 4
Dependent Claim
19 words
A gauge as claimed in claim 2 in which said transducer is a piezoelectric element associated with said beam.
Claim 5
Dependent Claim
17 words
A gauge as claimed in claim 3 in which said piezoelectric element is embedded in said beam.
Claim 6
Dependent Claim
19 words
A gauge as claimed in claim 2 in which said transducer is a strain gauge connected to said beam.
Claim 7
Dependent Claim
29 words
A gauge as claimed in claim 2 in which said transducer is a capacitance associated with said support and providing variations in airgap corresponding to variations in beam displacement.
Claim 8
Dependent Claim
32 words
A gauge as claimed in claim 2 in which said transducer comprises a magnetic reluctance device associated with said beam and providing a reluctance path variably corresponding to variations in support displacement.
Claim 9
Dependent Claim
23 words
A gauge as claimed in claim 2 in which an a.c. amplifier is provided to amplify the a.c. signal generated by said transducer.
Claim 10
Dependent Claim
15 words
A gauge as claimed in claim 8 in which said indicator means comprises an oscilloscope.
Claim 11
Dependent Claim
16 words
A gauge as claimed in claim 8 in which said indicator means comprises an r.m.s. meter.
Claim 12
Dependent Claim
30 words
A gauge as claimed in claim 1 in which protective shroud means are provided to enclose said beam and isolate same from external forces except those applied through said lift-sensor.
Claim 13
Dependent Claim
21 words
A gauge as claimed in claim 1 in which said beam has a resonant frequency above about 10,000 cycles per second.
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) | 1975-10-10 | 1976-04-10 | 1976-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-10 | 1980-04-10 | 1980-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-10 | 1984-04-10 | 1984-10-10 | $7700.00 | Window Closed / Lapsed |