US4372165A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for measuring fluid flow
Assignee: ITT Inc
•
Filing: 1980-09-10
•
Granted: 1983-02-08
•
Expires: 2000-09-10
Abstract
Abstract A fluid flowmeter of the vortex shedding type. The vortex frequency is determined from variations in the internal reflectivity of a prism 16 mounted in the fluid and coupled to a light source 13 and to a detector/frequency meter 14 via an optical waveguide arrangement 15. Passage of a vortex adjacent the prism 16 causes a temporary change in the local fluid refractive index and hence a change in the intensity of light internally reflected by the prism.
Inventors
- 👤 Gillies D. Pitt
- 👤 Roger J. Williamson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:27
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/05; G01F1/20; G01F1/32; G01F1/325
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
138 words
A fluid flowmeter of the type in which the flow velocity of a fluid is determined by measuring the frequency at which vortices are shed from a bluff body arranged in the fluid stream, comprising: a prism mounted on said bluff body in the fluid stream; a light source and means for directing light into said prism so as to provide an internally reflected beam; means for measuring the intensity of said reflected beam; and a frequency meter coupled to the output of said intensity measuring means to determine the rate of variation of said reflected beam intensity, said prism being constructed with respect to said light directing means so that the reflectivity of at least one surface of said prism varies in response to variations in the refractive index of the fluid caused by passing fluid vortices.
Claim 2
Dependent Claim
138 words
A fluid flowmeter of the type in which the flow velocity of a fluid is determined by measuring the frequency at which vortices are shed from a bluff body arranged in the fluid stream, comprising: a prism mounted on said bluff body in the fluid stream; a light source and means for directing light into said prism so as to provide an internally reflected beam; means for measuring the intensity of said reflected beam; and a frequency meter coupled to the output of said intensity measuring means to determine the rate of variation of said reflected beam intensity, said prism being constructed with respect to said light directing means so that the reflectivity of at least one surface of said prism varies in response to variations in the refractive index of the fluid caused by passing fluid vortices.
Claim 3
Dependent Claim
17 words
A flowmeter according to claim 1 in which said light source is defined as a monochromatic source.
Claim 4
Dependent Claim
27 words
A fluid flowmeter as claimed in claim 2, and wherein said prism is so constructed that light strikes at least one facet substantially at the critical angle.
Claim 5
Dependent Claim
20 words
A fluid flowmeter as claimed in claim 2 or 3, and wherein said light source is a semiconductor light-emitting device.
References Cited (Backward Citations)
US2807976A
Cited
US3572117A
Cited
US3732731A
Cited
US3733897A
Cited
GB1483818A
Cited
FR2301808A1
Cited
JPS5251988A
Cited
US4206642A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-02-07 | 1986-08-09 | 1987-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-02-07 | 1990-08-09 | 1991-02-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-02-07 | 1994-08-09 | 1995-02-08 | $7700.00 | Window Closed / Lapsed |