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Patent US3904876A successfully refreshed from Google Patents.
US3904876A
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Determination of paper ash content by X-ray absorption analysis
Assignee: NewPage Wisconsin System Inc
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Filing: 1974-09-20
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Granted: 1975-09-09
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Expires: 1994-09-20
Abstract
Abstract Paper containing unknown amounts of a plurality of different minerals, such as titanium dioxide, calcium carbonate, and clay, is subjected to x-ray absorption analysis to quickly determine the weight of each mineral per unit area of the paper. The quantities of the heavier elements are determined by x-ray absorption-edge spectrometry, and the clay is determined by using a single absorption measurement, combined with the data for the heavier elements and the measured mass per unit area of the paper. The technique is adaptable to determine ash content during production of the paper, wherein the necessary readings are obtained with respect to a moving web.
Inventors
- 👤 Frank P Arendt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 08:20
CPC Classifications
G; G01; G01N; G01N23/00; G01N23/02; G01N23/06; G01N23/16; G01N23/083
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
99 words
A METHOD FOR QUANTITATIVELY DETERMINING THE CONSTITUTENTS OF PAPER CONTAINING CELLULOSE, CLAY AND FROM NIL TO A SIGNIFICANT AMOUNT OF OTHER ELEMENTS HAVING AN ATOMIC NUMBER GREATER THAN 16, COMPRISING THE STEPS OF DETERMINING THE AMOUNT OF SAID OTHER ELEMENTS BY X-RAY ABSORPTION-EDGE ANALYSIS, MEASURING THE TOTAL MASS PER UNIT AREA OF THE PAPER, AND DETERMINING THE AMOUNT OF CLAY BASED ON (1) THE ABSORPTION BY THE PAPER OF MONOCHROMATC X-RAYS HAVING AN ENERGY GREATER THAN ABOUT 2.6 KEV., (2) THE PREVIOUSLY DETERMINED AMOUNT OF SAID OTHER ELEMENTS, AND (3), THE TOTAL MASS PER UNIT AREA OF THE PAPER.
Claim 2
Independent Claim
99 words
A METHOD FOR QUANTITATIVELY DETERMINING THE CONSTITUTENTS OF PAPER CONTAINING CELLULOSE, CLAY AND FROM NIL TO A SIGNIFICANT AMOUNT OF OTHER ELEMENTS HAVING AN ATOMIC NUMBER GREATER THAN 16, COMPRISING THE STEPS OF DETERMINING THE AMOUNT OF SAID OTHER ELEMENTS BY X-RAY ABSORPTION-EDGE ANALYSIS, MEASURING THE TOTAL MASS PER UNIT AREA OF THE PAPER, AND DETERMINING THE AMOUNT OF CLAY BASED ON (1) THE ABSORPTION BY THE PAPER OF MONOCHROMATC X-RAYS HAVING AN ENERGY GREATER THAN ABOUT 2.6 KEV., (2) THE PREVIOUSLY DETERMINED AMOUNT OF SAID OTHER ELEMENTS, AND (3), THE TOTAL MASS PER UNIT AREA OF THE PAPER.
Claim 3
Dependent Claim
50 words
The method of claim 1 wherein the step of determining the amount of said other elements comprises the steps of conducting monochromatic x-ray intensity loss measurements through the paper, said x-rays having respective energies which are respectively above and below the x-ray absorption edge characteristic of the respective other elements.
Claim 4
Dependent Claim
42 words
The method of claim 2 wherein at least one of the monochromatic x-rays has an energy falling between the respective absorption edges of two of said other elements, said one x-rays being used as a factor to determine both of said elements.
Claim 5
Independent Claim
140 words
A method for quantitatively determining the amount of constituents of paper consisting essentially of unknown amounts per unit area of cellulose, clay and from nil to a significant amount of calcium and titanium, comprising the steps of conducting respective x-ray absorption measurements with the chromium K Alpha , titanium K Alpha and calcium K Alpha , using the chromium K Alpha and titanium K Alpha absorptions to determine the mass per unit area of titanium, using the titanium K Alpha and calcium K Alpha absorptions to determine the mass per unit area of calcium, measuring the total mass per unit area of the paper, and determining the amount of clay based on the absorption of the calcium K Alpha energy, the amount, if any, of previously determined titanium and calcium, and the total mass per unit area of the paper.
Claim 6
Independent Claim
140 words
A method for quantitatively determining the amount of constituents of paper consisting essentially of unknown amounts per unit area of cellulose, clay and from nil to a significant amount of calcium and titanium, comprising the steps of conducting respective x-ray absorption measurements with the chromium K Alpha , titanium K Alpha and calcium K Alpha , using the chromium K Alpha and titanium K Alpha absorptions to determine the mass per unit area of titanium, using the titanium K Alpha and calcium K Alpha absorptions to determine the mass per unit area of calcium, measuring the total mass per unit area of the paper, and determining the amount of clay based on the absorption of the calcium K Alpha energy, the amount, if any, of previously determined titanium and calcium, and the total mass per unit area of the paper.
Claim 7
Dependent Claim
29 words
The method of claim 4 wherein the mass per unit area of the paper is determined with respect to the degree of absorption of beta rays by the paper.
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) | 1978-09-08 | 1979-03-10 | 1979-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-08 | 1983-03-10 | 1983-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-08 | 1987-03-10 | 1987-09-09 | $7700.00 | Window Closed / Lapsed |