US3693438A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Karman{40 s vortices generating device
Assignee: Yokogawa Electric Corp
•
Filing: 1971-04-23
•
Granted: 1972-09-26
•
Expires: 1991-04-23
Abstract
Abstract A vortex generating element of the type used in flow metering apparatus and having a generally elongate cylindrical shape mounted in a stream of flowing fluid so as to produce Karman''s vortices at a rate proportional to the velocity of the flowing fluid, with means detecting the production of vortices to give a linearly related measure of fluid velocity. To improve the correspondence of vortex production rate with flow velocity over wide conditions of flow, the element is formed on opposite sides thereof with recessed surface portions meeting the upstream surface of the element in an edge which lies substantially where the boundary layer of the fluid separates from the element surface during low velocity conditions of flow. The recessed surface portion meets the downstream surface of the element inwardly of said edge, whereby said edge forms an outer extremity of said element to said fluid flow and compels boundary layer separation.
Inventors
- 👤 Hiroo Yamasaki
- 👤 Yoshio Kurita
- 👤 Yutaka Ishikawa
- 👤 Takehiro Sawayama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:33
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/05; G01F1/20; G01F1/32; G01F1/325; G01F1/3209; G01F1/3218
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
173 words
A vortex generation element of the type used in flow metering apparatus and having a generally elongate cylindrical shape placed transversely in a stream of fluid to produce on opposite sides of the element vortices which are shed in alternating fashion, the flow metering apparatus having means for measuring the frequency of vortex production to determine the velocity of the fluid stream, such element being characterized in that: the element has formed on opposite sides thereof a recessed surface portion meeting the upstream surface of the element in an edge located at an angle, measured from the edge to the cylinder center to the cylinder stagnation point, lying within the range of angles at which the boundary layer of the fluid separates from the surface of an unrecessed cylindrical element at fluid velocities for which the rate of vortex production is substantially linearly related to fluid velocity; and meeting the downstream surface of the element inwardly of said edge, whereby said edge forms an outer extremity of said element to said fluid flow.
Claim 2
Dependent Claim
173 words
A vortex generation element of the type used in flow metering apparatus and having a generally elongate cylindrical shape placed transversely in a stream of fluid to produce on opposite sides of the element vortices which are shed in alternating fashion, the flow metering apparatus having means for measuring the frequency of vortex production to determine the velocity of the fluid stream, such element being characterized in that: the element has formed on opposite sides thereof a recessed surface portion meeting the upstream surface of the element in an edge located at an angle, measured from the edge to the cylinder center to the cylinder stagnation point, lying within the range of angles at which the boundary layer of the fluid separates from the surface of an unrecessed cylindrical element at fluid velocities for which the rate of vortex production is substantially linearly related to fluid velocity; and meeting the downstream surface of the element inwardly of said edge, whereby said edge forms an outer extremity of said element to said fluid flow.
Claim 3
Dependent Claim
34 words
An element as claimed in claim 1 wherein said edge is located at an angle of between approximately 70* and 105* measured from the edge to the cylinder center to the cylinder stagnation point.
Claim 4
Dependent Claim
18 words
An element as claimed in claim 2 wherein said angle is within the range of 75* to 85*.
Claim 5
Dependent Claim
20 words
An element as claimed in claim 1 wherein said recessed surface portion is formed of at least one flat plane.
Claim 6
Dependent Claim
44 words
An element as claimed in claim 4 wherein said recessed portion is formed of two flat planes, the rear one of which is parallel to the direction of fluid flow and the front one of which is perpendicular to the direction of fluid flow.
Claim 7
Dependent Claim
17 words
An element as claimed in claim 1 wherein said recessed portion is formed of a curved surface.
Claim 8
Dependent Claim
15 words
An element as claimed in claim 1 wherein said cylinder is a right circular cylinder.
Claim 9
Dependent Claim
14 words
An element as claimed in claim 1 wherein said cylinder is an elliptical cylinder.
Claim 10
Dependent Claim
26 words
An element as claimed in claim 1 wherein said element further comprises means extending through said element between said recessed portions for communicating fluid fluctuations therebetween.
Claim 11
Dependent Claim
25 words
An element according to claim 9 wherein said communication means comprises a row of openings in said recessed portions arranged parallel to said element axis.
Claim 12
Dependent Claim
36 words
An element as claimed in claim 9 wherein said communicating means comprises a pair of interior cavities separated by a partition having a passageway therethrough, an opening means connecting said cavities with said recessed surface portions.
Claim 13
Dependent Claim
16 words
An element as claimed in claim 11 wherein said opening means comprises a row of holes.
Claim 14
Dependent Claim
14 words
An element as claimed in claim 11 wherein said opening means comprises a slot.
Claim 15
Dependent Claim
15 words
An element as claimed in claim 11 wherein said passageway comprises a row of holes.
Claim 16
Dependent Claim
21 words
An element according to claim 11 wherein said measuring means is mounted in said passageway for detecting the fluid fluctuations therein.
Claim 17
Dependent Claim
23 words
An element as claimed in claim 9 wherein said measuring means is mounted in said communicating means for detecting the fluid fluctuations therein.
Claim 18
Dependent Claim
25 words
An element as claimed in claim 1 wherein said measuring means is mounted on the downstream surface of said element for detecting fluid fluctuation therealong.
Claim 19
Dependent Claim
51 words
An element according to claim 1 wherein said measuring means is located downstream of said element, said measuring means comprising means transmitting a sound impulse transverse to the path of said vortices, and means responsive to variations in the transmission times of said impulses caused by the passage of said vortices.
References Cited (Backward Citations)
US3116639A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-09-26 | 1976-03-27 | 1976-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-26 | 1980-03-27 | 1980-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-26 | 1984-03-27 | 1984-09-26 | $7700.00 | Window Closed / Lapsed |