US3834818A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Continuous measurement of the fineness of a pulverulent material
Assignee: CENTRE D ETUDES ET DE RECH LIANTS HYDRAULIQUES FR
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Filing: 1973-03-26
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Granted: 1974-09-10
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Expires: 1993-03-26
Abstract
Abstract In order to measure the degree of fineness of a pulverulent material, the pulverulent material is placed in suspension in a gaseous fluid and a converging laser beam from an optical source is passed through the fluid. The luminous flux of the diffracted light is measured by two or more photoelectric cells in the focal plane of the optical system, the cells being at different distances from the optical axis. The fineness of the material is calculated on the basis of the result of these measurements.
Inventors
- 👤 J Meric
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 07:01
CPC Classifications
G; G01; G01N; G01N15/00; G01N15/02; G01N15/0205
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
89 words
A method of determining the fineness of a pulverulent material, comprising: placing the pulverulent material in suspension in a gaseous fluid; passing through the fluid a converging laser beam issuing from an optical system, the beam being diffracted by the material; measuring the luminous flux of the diffracted light at at least two points situated in the focal plane of the optical system, outside the focus of the beam, and at difFerent distances from this focus; and calculating the fineness of the material from the result of these measurements.
Claim 2
Independent Claim
89 words
A method of determining the fineness of a pulverulent material, comprising: placing the pulverulent material in suspension in a gaseous fluid; passing through the fluid a converging laser beam issuing from an optical system, the beam being diffracted by the material; measuring the luminous flux of the diffracted light at at least two points situated in the focal plane of the optical system, outside the focus of the beam, and at difFerent distances from this focus; and calculating the fineness of the material from the result of these measurements.
Claim 3
Dependent Claim
51 words
A method as claimed in claim 1, in which one of the said points lies inside a diffraction cone whose half-angle at the apex is 0.8/d radian, d being the material particle diameter selected to characterize the fineness of the material, another of the said points lying outside the said cone.
Claim 4
Dependent Claim
15 words
A method as claimed in claim 2, in which the said half-angle is 0.1 radian.
Claim 5
Dependent Claim
85 words
Apparatus for determining the fineness of a pulverulent material, comprising means for placing the pulverulent material in suspension in a gaseous fluid, a laser for generating a laser beam, an optical system arranged to cause the laser beam to converge and for the convergent beam to pass through the suspension of pulverulent material in the gaseous fluid, and at least two photoelectric cells disposed in the focal plane of the optical system, outside the focus of the beam and at different distances from this focus.
Claim 6
Dependent Claim
85 words
Apparatus for determining the fineness of a pulverulent material, comprising means for placing the pulverulent material in suspension in a gaseous fluid, a laser for generating a laser beam, an optical system arranged to cause the laser beam to converge and for the convergent beam to pass through the suspension of pulverulent material in the gaseous fluid, and at least two photoelectric cells disposed in the focal plane of the optical system, outside the focus of the beam and at different distances from this focus.
Claim 7
Dependent Claim
50 words
Apparatus as claimed in claim 4, in which one of the cells is disposed inside a diffraction cone whose half-angle at the apex is 0.8/d radian, d being the material particle diameter selected to characterize the fineness of the material, another of the cells being disposed outside the said cone.
Claim 8
Dependent Claim
20 words
Apparatus as claimed in claim 5, in which the said cone has a half-angle at the apex of 0.1 radian.
Claim 9
Dependent Claim
38 words
Apparatus as claimed in claim 4, in which the means for placing the pulverulent material in suspension comprises a compressed air duct having an inlet for the material, and a convergent-divergent nozzle at the outlet of the duct.
Claim 10
Dependent Claim
25 words
Apparatus as claimed in claim 7, in which the nozzle is surrounded by a secondary air inlet conduit discharging at the extremity of the nozzle.
Claim 11
Dependent Claim
72 words
Apparatus as claimed in claim 7, in which the means for placing the pulverulent material in suspension further comprises a disc having an annular groove, means for rotating the disc, means for supplying the pulverulent material onto the disc so that it fills the groove, and a hollow needle, one end of which extends into the groove whereas its other end is connected to the material inlet of the compressed air duct.
Claim 12
Dependent Claim
18 words
Apparatus as claimed in claim 9, in which the groove has a triangular cross-section with a rounded bottom.
Claim 13
Dependent Claim
30 words
Apparatus as claimed in claim 9, in which the end of the needle in the groove is provided with a bevel facing in the direction of rotation of the disc.
Claim 14
Dependent Claim
31 words
Apparatus as claimed in claim 9, in which the means for supplying the pulverulent material comprises a funnel whose wall has a slot through which the disc projects into the funnel.
Claim 15
Dependent Claim
20 words
Apparatus as claimed in claim 9, further comprising at least one scraper arranged to level the material in the groove.
References Cited (Backward Citations)
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US3328587A
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US3467471A
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Cited
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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) | 1977-09-09 | 1978-03-11 | 1978-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-09 | 1982-03-11 | 1982-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-09 | 1986-03-11 | 1986-09-10 | $7700.00 | Window Closed / Lapsed |