US4019066A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Measuring the surface roughness of a moving sheet material
Assignee: Domtar Inc
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Filing: 1975-03-25
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Granted: 1977-04-19
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Expires: 1995-03-25
Abstract
Abstract The invention is concerned with measuring "on-line" the surface roughness of a moving sheet material, e.g. a paper web. The method comprises illuminating the moving web, preferably at a low angle, suitably collecting the light reflected from the moving web and processing the light by means of a sensitive photo-electrical system. The electrical signals thus obtained are divided into an AC and a DC component, the components are separately measured and their ratio used as an index of roughness. An apparatus for carrying out roughness measurements on a moving paper web, e.g. on a paper machine, is described.
Inventors
- 👤 John M. Lucas
- 👤 Serge Gracovetsky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 03:57
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/30; Y; Y10; Y10S; Y10S162/00; Y10S162/09; Y10S162/10
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
167 words
An apparatus for the on-line measuring of the surface roughness of a moving web which comprises; illuminating means for projecting a beam of light obliquely onto the surface of said web; collector means disposed to collect scattered light reflected at a non-specular angle from a small area of said surface; a support structure adapted to be placed adjacent said surface, said illuminating means and said collector means being fixedly set in said support; means providing relative movement between said web and said support thereby to collect reflected light from a multiplicity of small areas sequentially appearing in front of said collector means; photoelectric means for converting the light collected from the said small areas into electrical signals; and analyzer means for converting said electrical signals into an index of roughness, said analyzer means comprising means for dividing said electrical signals into a direct component and on alternating component and for computing the ratio of said alternating to said direct component, said ratio providing said index of roughness.
Claim 2
Independent Claim
167 words
An apparatus for the on-line measuring of the surface roughness of a moving web which comprises; illuminating means for projecting a beam of light obliquely onto the surface of said web; collector means disposed to collect scattered light reflected at a non-specular angle from a small area of said surface; a support structure adapted to be placed adjacent said surface, said illuminating means and said collector means being fixedly set in said support; means providing relative movement between said web and said support thereby to collect reflected light from a multiplicity of small areas sequentially appearing in front of said collector means; photoelectric means for converting the light collected from the said small areas into electrical signals; and analyzer means for converting said electrical signals into an index of roughness, said analyzer means comprising means for dividing said electrical signals into a direct component and on alternating component and for computing the ratio of said alternating to said direct component, said ratio providing said index of roughness.
Claim 3
Dependent Claim
14 words
The apparatus of claim 1 further comprising means of displaying said index of roughness.
Claim 4
Dependent Claim
27 words
The apparatus of claim 1 wherein said illuminating means is set to project a beam of light an an angle to the surface between 5° and 50°.
Claim 5
Dependent Claim
36 words
The apparatus of claim 1 wherein said collector means is provided with an aperture limiting the light collected by said collector means to that reflected from an area of said surface having dimensions about 0.01-2 mm.
Claim 6
Dependent Claim
28 words
The apparatus of claim 1 wherein said photoelectric means comprises a detector responsive to light intensity variations up to a frequency of the order of 100,000 per second.
Claim 7
Dependent Claim
33 words
The apparatus of claim 1 further comprising means for finding the value of said direct component while said beam of light is extinguished thereby to set a "zero" value of said direct component.
Claim 8
Independent Claim
96 words
A method of measuring the surface roughness of a moving web which comprises; projecting a beam of light obliquely onto said surface; collecting scattered light reflected at a non specular angle from a small area of said surface; continuously moving said web thereby to collect scattered reflected light from a continuous sequence of small areas of said surface; converting the collected light to electrical signals; analyzing said electrical signals into a direct component and an alternating components; computing the ratio of values of said direct and said alternating components said ratio providing an index of roughness.
Claim 9
Independent Claim
96 words
A method of measuring the surface roughness of a moving web which comprises; projecting a beam of light obliquely onto said surface; collecting scattered light reflected at a non specular angle from a small area of said surface; continuously moving said web thereby to collect scattered reflected light from a continuous sequence of small areas of said surface; converting the collected light to electrical signals; analyzing said electrical signals into a direct component and an alternating components; computing the ratio of values of said direct and said alternating components said ratio providing an index of roughness.
Claim 10
Dependent Claim
15 words
The method of claim 7 wherein the angle of incidence is between 5° and 50°.
Claim 11
Dependent Claim
15 words
The method of claim 8 wherein the angle of incidence is between 15° and 30°.
Claim 12
Dependent Claim
36 words
The method of claim 7 wherein the light continuously collected is the one reflected from a continuous sequence of areas on the surface of the paper said areas having dimensions of the order of 0.01-2 mm.
Claim 13
Dependent Claim
21 words
The method of claim 7 wherein the magnitude of said alternating component is measured as the RMS of said alternating component.
Claim 14
Dependent Claim
25 words
The method of claim 7 wherein the index of roughness is calculated as the ratio of the magnitudes of said direct and said alternating components.
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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) | 1980-04-18 | 1980-10-18 | 1981-04-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-18 | 1984-10-18 | 1985-04-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-18 | 1988-10-18 | 1989-04-19 | $7700.00 | Window Closed / Lapsed |