US4741200A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for measuring viscosity in a liquid utilizing a piezoelectric sensor
Assignee: Ford Motor Co
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Filing: 1986-07-11
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Granted: 1988-05-03
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Expires: 2006-07-11
Abstract
Abstract A piezoelectric element energized to exhibit thickness-shear mode vibration is utilized to measure the viscosity of liquids. Electrodes, of an inert material are bonded to the major faces of the disc shaped crystal and are of a lesser diameter than the crystal surfaces so as to provide a concentric ring area of the crystal that is unenergized.
Inventors
- 👤 Robert H. Hammerle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 08:19
CPC Classifications
G; G01; G01N; G01N11/00; G01N11/10; G01N11/16
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
80 words
An apparatus for measuring the viscosity of liquids comprising: piezoelectric means containing a thickness shear mode crystal with opposing major surfaces, opposing electrodes mounted on said major surfaces and lead wires correspondingly connected to said electrodes for suspending said thickness shear mode crystal and conveying electrical drive energy to said electrodes; energization means for supplying AC electrical drive energy to said piezoelectric means; and detection means for monitoring electrical characteristics of said piezoelectric means when driven by said energization means.
Claim 2
Independent Claim
80 words
An apparatus for measuring the viscosity of liquids comprising: piezoelectric means containing a thickness shear mode crystal with opposing major surfaces, opposing electrodes mounted on said major surfaces and lead wires correspondingly connected to said electrodes for suspending said thickness shear mode crystal and conveying electrical drive energy to said electrodes; energization means for supplying AC electrical drive energy to said piezoelectric means; and detection means for monitoring electrical characteristics of said piezoelectric means when driven by said energization means.
Claim 3
Dependent Claim
36 words
A viscosity measuring apparatus as in claim 1, wherein said thickness shear mode crystal has a circular disc shape and said electrodes are thin films of conducting material disposed on portions of said circular major surfaces.
Claim 4
Dependent Claim
58 words
A viscosity measuring apparatus as in claim 2, wherein said opposing electrodes are substantially circular in shape but of a lesser diameter than said thickness shear mode crystal and concentrically mounted on said thickness shear mode crystal so as to provide an outer circular ring on said thickness shear mode crystal in which the electrodes are not opposing.
Claim 5
Dependent Claim
58 words
A viscosity measuring apparatus as in claim 3, wherein said opposing electrodes each have a portion extending from said circular shape in opposite directions to diametrically opposite edges of said thickness shear mode crystal and said lead wires are connected to said opposite edges of said thickness shear mode crystal and to said extended portions of said electrodes.
Claim 6
Dependent Claim
50 words
A viscosity sensing apparatus as in claim 4, wherein said energization means has an adjustable frequency output and said detection means indicates when the thickness shear mode crystal has reached a resonant vibrational state in response to said energization means providing a known frequency of drive energy to said crystal.
Claim 7
Dependent Claim
23 words
A viscosity measuring apparatus as in claim 1, wherein said piezoelectric means further includes an insulating mount means for supporting said lead wires.
Claim 8
Independent Claim
83 words
A method for measuring the viscosity of liquids comprising: providing piezoelectric means containing a thickness shear mode crystal with opposing major surfaces, opposing electrodes mounted on said major surfaces and lead wires correspondingly connected to said electrodes for suspending said thickness shear mode crystal and conveying electrical drive energy to said electrodes; providing energization means for supplying AC electrical drive energy to said piezoelectric means; and providing detection means for monitoring electrical characteristics of said piezoelectric means when driven by said energization means.
Claim 9
Independent Claim
83 words
A method for measuring the viscosity of liquids comprising: providing piezoelectric means containing a thickness shear mode crystal with opposing major surfaces, opposing electrodes mounted on said major surfaces and lead wires correspondingly connected to said electrodes for suspending said thickness shear mode crystal and conveying electrical drive energy to said electrodes; providing energization means for supplying AC electrical drive energy to said piezoelectric means; and providing detection means for monitoring electrical characteristics of said piezoelectric means when driven by said energization means.
Claim 10
Dependent Claim
41 words
A method of measuring viscosity as in claim 7, wherein said thickness shear mode crystal is provided in a circular disc shape and said electrodes are provided as thin films of conducting material disposed on portions of said circular major surfaces.
Claim 11
Dependent Claim
61 words
A method of measuring viscosity as in claim 8, wherein said opposing electrodes are provided as substantially circular in shape but of a lesser diameter than said thickness shear mode crystal and concentrically mounted on said thickness shear mode crystal so as to provide an outer circular ring on said thickness shear mode crystal in which the electrodes are not opposing.
Claim 12
Dependent Claim
62 words
A method of measuring viscosity as in claim 9, wherein said opposing electrodes are each provided to have a portion extending from said circular shape in opposite directions to diametrically opposite edges of said thickness shear mode crystal and said lead wires are connected to said opposite edges of said thickness shear mode crystal and to said extended portions of said electrodes.
Claim 13
Dependent Claim
56 words
A method of measuring viscosity as in claim 10, wherein said energization means is provided with an adjustable frequency output and said detector means is provided to indicate when the thickness shear mode crystal has reached a resonant vibrational state in response to said energization means providing a known frequency of drive energy to said crystal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-05-03 | 1991-11-02 | 1992-05-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-03 | 1995-11-02 | 1996-05-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-03 | 1999-11-02 | 2000-05-03 | $7700.00 | Window Closed / Lapsed |