US4791353A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Scanning combination thickness and moisture gauge for moving sheet material
Assignee: IMPACT SYSTEMS Inc SAN JOSE CALIFORNIA A CORP OF
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Filing: 1987-08-14
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Granted: 1988-12-13
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Expires: 2007-08-14
Abstract
Abstract A combination caliper/moisture sensor in the form of a scanner in the cross-direction of sheet material being manufactured by a papermaking machine includes a pair of capacitive plates on opposite sides of the moving sheet material and in substantial contact with it which are utilized for measuring capacitance between the juxtaposed plates which are spaced in accordance with the caliper of the paper. Then a magnetic circuit which provides a flux path through the paper is utilized for measuring caliper which is the independent variable of the capacitance equation which, when solved, yields the dielectric constant. Since there is a known relationship between percent moisture and the dielectric constant, the percent moisture of the sheet material can be determined.
Inventors
- 👤 Pekka Typpo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 09:52
CPC Classifications
G; G01; G01R; G01R27/00; G01R27/02; G01R27/26; G01R27/2617; G01R27/2635; G01R27/2641; G01B; G01B7/00; G01B7/02; G01B7/06; G01B7/08; G01B7/087; G01N; G01N27/00; G01N27/02; G01N27/22; G01N27/223; G01N33/00; G01N33/34; G01N33/346
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
121 words
A scanning combination thickness and moisture gauge for moving sheet material comprising: a pair of conductive plate means adapted for substantially contacting opposite sides of said moving sheet material and forming a capacitor whose capacitance is proportional to moisture in said sheet material and inversely proportional to thickness (caliper) of said sheet material between said plate means; means for measuring said capacitance; magnetic means integrally associated with said plate means for providing a magnetic flux path through said sheet material for measuring said thickness including passive magnetic means, carried by one of said pairs of plate means, for forming a part of said magnetic flux path; and electrical processing means responsive to said measured capacitance and thickness for determining said moisture.
Claim 2
Dependent Claim
121 words
A scanning combination thickness and moisture gauge for moving sheet material comprising: a pair of conductive plate means adapted for substantially contacting opposite sides of said moving sheet material and forming a capacitor whose capacitance is proportional to moisture in said sheet material and inversely proportional to thickness (caliper) of said sheet material between said plate means; means for measuring said capacitance; magnetic means integrally associated with said plate means for providing a magnetic flux path through said sheet material for measuring said thickness including passive magnetic means, carried by one of said pairs of plate means, for forming a part of said magnetic flux path; and electrical processing means responsive to said measured capacitance and thickness for determining said moisture.
Claim 3
Dependent Claim
40 words
A gauge as in claim 1 where said magnetic means comprises active magnetic means including a U-shaped pole piece having two legs with ends each of them terminating in an aperture in the other of said pair of plate means.
Claim 4
Dependent Claim
29 words
A gauge as in claim 1 where said passive magnetic means has a dielectric constant greater than 10 to make it electrically transparent to said measurement of said capacitance.
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) | 1991-12-13 | 1992-06-13 | 1992-12-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-13 | 1996-06-13 | 1996-12-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-13 | 2000-06-13 | 2000-12-13 | $7700.00 | Window Closed / Lapsed |