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EP0590841A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Particle size measuring device

Assignee: Shimadzu Corp
•
Filing: 1993-09-20
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Granted: —
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Expires: 2013-09-20
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Abstract

Abstract The device includes a laser (21) photo-sensors (23) for measuring the spatial intensity distribution of diffracting and scattering light from the specimen (22), an arithmetic unit (24) for calculating particle size distribution, a first judging means (25) for monitoring outputs from selected photo-sensors so as to see if the monitored outputs exceed a first reference (X₁) so as to know that the specimen is present in the optical system, a second judging means (26) for storing the outputs of all the photo-sensors when the specimen is present in the optical system, and seeing if a maximum value of the outputs falls within a range defined by a second and a third reference (X₂ - X₃) so as to know that the concentration of the specimen is optimal for measuring, a storage (28) for storing the outputs of all the photo-sensors as effective data only when the maximum value falls within the reference range, a third judging means (27) for seeing if predetermined sets of effective data have been stored in the storage, wherein the arithmetic unit is operated when it is found that the predetermined sets of effective data are stored in the storage.

Inventors

  • 👤 Takeshi Niwa

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-24 17:43
CPC Classifications
G; G01; G01N; G01N15/00; G01N15/02; G01N15/0205; G01N15/0211; G01N21/00; G01N21/17; G01N21/47; G01N2021/4704; G01N2021/4711; G01N2021/4716

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 234 words
A device for measuring particle size distribution of powdery solids, the device comprising: a laser for radiating laser beam upon a specimen of the powdery solids; an optical measuring system including a plurality of photosensors for measuring the spatial intensity distribution of diffracting and scattering light upon the specimen; an arithmetic unit for calculating a particle size distribution of the specimen on the basis of the spatial intensity distribution measured by the photo-sensors; a first judging means ror monitoring outputs from a predetermined number of photo-sensors and seeing if the monitored outputs exceed a first reference so as to know that the specimen are present in the optical measuring system; a second judging means for storing the outputs of all the photo-sensors after the first judging means ascertains that the specimen is present in the optical measuring system, and seeing if a maximum value of the outputs falls within a range defined by a second reference and a third reference so as to know that the concentration of the specimen is optimal for measuring; a storage for storing the outputs of all the photo-sensors as effective data only when the second means ascertains that the maximum value falls within the range defined by the second and third references; and a third judging means for seeing if predetermined sets of effective data have been stored in the storage so as to operate the arithmetic unit.
Claim 2
Dependent Claim 89 words
The device according to claim 1, further comprising a fourth judging means for seeing if a difference between the maximum value of all the outputs of the photo-sensors and the previous maximum value is equal to or smaller than a fourth reference, during the period of time when the second judging means ascertains that the concentration of the specimen falls within a required range, wherein the storage stores all the outputs of the photo-sensors as effective data when the difference is equal to or smaller than the fourth reference.
Claim 3
Dependent Claim 30 words
The device according to claim 1 or 2, wherein the photosensors are constituted by ring detectors having different radii arranged concentric of an optical axis of the optical measuring system.
Claim 4
Independent Claim 125 words
A method of measuring particle size distribution of powdery solids, wherein the powder is suspended in a gaseous medium and the spatial intensity distribution resulting from diffraction and scattering of a laser beam incident on the suspension is measured by means of photo-sensors, the particle size distribution being calculated as a function of the spatial intensity distribution, characterized in that the outputs from a predetermined number of photo-sensors are monitored to determine whether a powder specimen is present in the laser beam, the outputs from all the photo-sensors are monitored to determine whether a desired range of concentration of the powder is present, and the outputs of the sensors are stored for subsequent processing only when a powder specimen is present at a desired concentration.

References Cited (Backward Citations)

FR2300337A1 Cited
EP0369654A1 Cited

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