US3668931A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Measuring the velocity of flow of an electrically conductive fluid
Assignee: Kent Instruments Ltd
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Filing: 1970-07-20
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Granted: 1972-06-13
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Expires: 1990-07-20
Abstract
Abstract An electromagnetic velocity meter is described, of the type in which an electric signal is generated in response to relative motion between the velocity meter and a conductive fluid in a magnetic field generated by means in the velocity meter, to provide a measure of the velocity of the relative motion. The velocity meter is particularly useful as a ship''s log, and may be arranged to be retractably mounted in a ship''s hull. A preferred form of the velocity meter is circular in cross section and has a pair of electrodes for sensing the electric signal, the electrodes being disposed on the flow meter in a manner tending to minimize misalignment error. It also has boundary layer trips to make the signal generated/velocity characteristic more nearly linear. Another preferred form mounts three or more electrodes for measuring components of the flow velocity in different directions, whereby the drift angle and velocity of the ship may be computed.
Inventors
- 👤 Klaus Joachim Zanker
- 👤 Derrick Norman Harrison
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:40
CPC Classifications
G; G01; G01P; G01P5/00; G01P5/08; G01P5/086
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
138 words
A velocity meter for providing an electric signal dependent on the speed of movement thereof relative to an electrically conductive fluid, the velocity meter comprising a housing having a passage therein with at least one open end, a casing movable in the passage between an inoperative position within the housing and an operative position projecting from the open end into the fluid, the casing containing means operable to produce a magnetic field in the fluid in the operative position of the casing, and a pair of electrodes carried on a portion of the casing of substantially circular cross section for contact with the fluid in the operative position to sense the electric potential difference due to the relative movement to provide the sigNal, the casing and the housing cooperating to prevent ingress of the fluid through the passage.
Claim 2
Dependent Claim
138 words
A velocity meter for providing an electric signal dependent on the speed of movement thereof relative to an electrically conductive fluid, the velocity meter comprising a housing having a passage therein with at least one open end, a casing movable in the passage between an inoperative position within the housing and an operative position projecting from the open end into the fluid, the casing containing means operable to produce a magnetic field in the fluid in the operative position of the casing, and a pair of electrodes carried on a portion of the casing of substantially circular cross section for contact with the fluid in the operative position to sense the electric potential difference due to the relative movement to provide the sigNal, the casing and the housing cooperating to prevent ingress of the fluid through the passage.
Claim 3
Dependent Claim
51 words
A velocity meter according to claim 1, wherein at least one further electrode is provided on said portion of the casing, the electrodes being equally spaced around the periphery of said portion to provide a plurality of electric signals dependent on components of the speed of relative movement in different directions.
Claim 4
Dependent Claim
26 words
A velocity meter according to claim 2, having two pairs of electrodes disposed at the ends of two perpendicular diameters of said portion of the casing.
Claim 5
Dependent Claim
25 words
A velocity meter according to claim 2, wherein one electrode of the pair is disposed on each of the two leading quadrants of said portion.
Claim 6
Dependent Claim
34 words
A velocity meter according to claim 4, wherein a boundary layer trip, extending parallel to the axis of the casing, is located on each of said leading quadrants of said portion of the casing.
Claim 7
Dependent Claim
39 words
A velocity meter according to claim 5, wherein the radius of said portion of the casing passing through each strip subtends an angle of approximately 80* to the radius of the casing passing through the front stagnation point thereof.
Claim 8
Dependent Claim
92 words
A velocity meter for providing an electric signal dependent on the speed of movement thereof relative to an electrically conductive fluid, the velocity meter comprising a casing, means in the casing for producing a magnetic field in the fluid, and a pair of electrodes carried on a portion of the casing of substantially circular cross-section for contact with the fluid to sense the electric potential difference between the electrodes due to such relative movement to provide the signal, one electrode being disposed on each of the two leading quadrants of said portion.
Claim 9
Dependent Claim
92 words
A velocity meter for providing an electric signal dependent on the speed of movement thereof relative to an electrically conductive fluid, the velocity meter comprising a casing, means in the casing for producing a magnetic field in the fluid, and a pair of electrodes carried on a portion of the casing of substantially circular cross-section for contact with the fluid to sense the electric potential difference between the electrodes due to such relative movement to provide the signal, one electrode being disposed on each of the two leading quadrants of said portion.
Claim 10
Dependent Claim
47 words
A velocity meter according to claim 7, wherein at least one boundary layer trip is provided on the surface of said portion of the casing for decreasing the transition fluid velocity at which the flow in the boundary layer of the casing changes from laminar to turbulent.
Claim 11
Dependent Claim
41 words
A velocity meter according to claim 8, wherein a pair of boundary layer trips is provided, each trip being parallel to the axis of the casing and one trip being located on each of the two leading quadrants of the casing.
Claim 12
Dependent Claim
36 words
A velocity meter according to claim 9, wherein the radius of the casing passing through each trip subtends an angle of substantially 80* to the radius of the casing passing through the front stagnation point thereof.
Claim 13
Dependent Claim
21 words
A velocity meter according to claim 9, wherein each boundary layer trip comprises a slot in the surface of the casing.
Claim 14
Dependent Claim
23 words
A velocity meter according to claim 9, wherein each boundary layer trip comprises a straight wire mounted on the surface of the casing.
Claim 15
Dependent Claim
22 words
A velocity meter according to claim 9, wherein each boundary layer trip comprises a roughened area on the surface of the casing.
References Cited (Backward Citations)
US2969673A
Cited
US3308659A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-13 | 1975-12-13 | 1976-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-13 | 1979-12-13 | 1980-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-13 | 1983-12-13 | 1984-06-13 | $7700.00 | Window Closed / Lapsed |