US3874221A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transducers
Assignee: SALARTRON ELECTRIC GROUP LIMIT
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Filing: 1972-05-03
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Granted: 1975-04-01
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Expires: 1992-05-03
Abstract
Abstract A transducer, e.g., for measuring gas density, comprises a sensing element consisting of a right cylindrical shell, means for maintaining hoop-mode vibrations in the shell and means for producing a signal whose frequency is dependent upon the frequency of these vibrations. At least one end of the shell is open and free to vibrate, so that a circumferential antinode may be formed at this open end. This reduces the range of operating frequencies of the transducer, thereby reducing the error introduced into density measurements by variations of the velocity of sound in the gas or gases whose density is being measured.
Inventors
- 👤 David John Deverill Lockie
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:30
CPC Classifications
G; G01; G01L; G01L9/00; G01L9/0001; G01L9/0008; G01N; G01N9/00; G01N9/002
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
119 words
A transducer for use in measuring a physical property of a fluid, the transducer comprising: a substantially rigid casing; a tubular hollow body disposed within said casing, said body being open at one end and having a tubular resilient wall of uniform thickness spaced from the casing to permit vibration of said wall; means for defining an inlet in said casing for permitting entry of fluid into said casing; means for elastically deforming said wall to excite bell-like vibration thereof; means for providing a signal representative of a frequency of the said vibration; and circumferential node-forming means at the other end of said body, said tubular wall of uniform thickness extending from said open end to said node-forming means.
Claim 2
Dependent Claim
119 words
A transducer for use in measuring a physical property of a fluid, the transducer comprising: a substantially rigid casing; a tubular hollow body disposed within said casing, said body being open at one end and having a tubular resilient wall of uniform thickness spaced from the casing to permit vibration of said wall; means for defining an inlet in said casing for permitting entry of fluid into said casing; means for elastically deforming said wall to excite bell-like vibration thereof; means for providing a signal representative of a frequency of the said vibration; and circumferential node-forming means at the other end of said body, said tubular wall of uniform thickness extending from said open end to said node-forming means.
Claim 3
Dependent Claim
57 words
A transducer according to claim 1, wherein said casing is provided with means defining an outlet for fluid, the outlet means being so arranged that fluid can pass from the inlet means to the outlet means though the hollow body and the space between the casing and the said wall without compressing or expanding the said body.
Claim 4
Dependent Claim
208 words
An improved transducer for use in measuring the density of a gas, the transducer comprising: a rigid casing; means in said casing for defining a gas inlet and a gas outlet; a sensing element comprising a right circular cylindrical tubular portion open at one end thereof; a circumferential node-forming structure at the other end of said element; means for securing said node-forming structuRe to said casing with said tubular portion of said sensing element spaced from the interior surface of the casing; means defining a flow path for gas between the gas inlet and the gas outlet whereby the interior and the exterior surfaces of the said tubular portion are equally exposed to gas; electromagnetic means mounted within said tubular portion for exciting and sensing hoop-mode vibration of said tubular portion, the sensing element being formed of ferromagnetic material; means for supplying electrical power to the said vibration exciting means; and means for coupling signals generated in the said vibration sensing means to output terminals; and wherein the improvement is that said tubular portion is of uniform wall thickness from said node-forming structure to said open end, whereby the sensing element is adapted to vibrate in the hoop-mode in which antinodes are present at the said open end.
Claim 5
Dependent Claim
208 words
An improved transducer for use in measuring the density of a gas, the transducer comprising: a rigid casing; means in said casing for defining a gas inlet and a gas outlet; a sensing element comprising a right circular cylindrical tubular portion open at one end thereof; a circumferential node-forming structure at the other end of said element; means for securing said node-forming structuRe to said casing with said tubular portion of said sensing element spaced from the interior surface of the casing; means defining a flow path for gas between the gas inlet and the gas outlet whereby the interior and the exterior surfaces of the said tubular portion are equally exposed to gas; electromagnetic means mounted within said tubular portion for exciting and sensing hoop-mode vibration of said tubular portion, the sensing element being formed of ferromagnetic material; means for supplying electrical power to the said vibration exciting means; and means for coupling signals generated in the said vibration sensing means to output terminals; and wherein the improvement is that said tubular portion is of uniform wall thickness from said node-forming structure to said open end, whereby the sensing element is adapted to vibrate in the hoop-mode in which antinodes are present at the said open end.
Claim 6
Dependent Claim
86 words
A transducer for measuring a physical property of a fluid, the transducer comprising a casing having an inlet and an outlet for fluid; a hollow cylindrical body open at at least one end thereof and substantially uniform in wall thickness throughout its axial length, whereby an antinode of vibration may be established at said one end; means for mounting the cylindrical body for vibration within the casing, means for exciting hoop mode vibration of said cylindrical body; and means for sensing the frequency of said vibration.
Claim 7
Dependent Claim
86 words
A transducer for measuring a physical property of a fluid, the transducer comprising a casing having an inlet and an outlet for fluid; a hollow cylindrical body open at at least one end thereof and substantially uniform in wall thickness throughout its axial length, whereby an antinode of vibration may be established at said one end; means for mounting the cylindrical body for vibration within the casing, means for exciting hoop mode vibration of said cylindrical body; and means for sensing the frequency of said vibration.
Claim 8
Dependent Claim
39 words
A transducer according to claim 4, wherein said cylindrical body is open at both ends thereof; and wherein said means for mounting is arranged to permit the establishment of respective antinodes of said vibration of both of said ends.
Claim 9
Dependent Claim
35 words
A transducer according to claim 5 wherein said means for mounting includes a flexible interconnecting member extending between said casing and each end of said body to support said body and permit free vibration thereof.
Claim 10
Dependent Claim
37 words
A transducer according to claim 4 wherein said means for mounting comprises at least one flexible interconnecting member extending between an end of said body and said casing to support said body and permit free vibration thereof.
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) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |