| 摘要 |
A dry particle size distribution measuring apparatus comprises a measurement flow cell (2) provided with light transmissive windows (3,4), a first conduit (10) for introducing a particulate sample (5) into the flow cell along a flow axis (27), a laser (7) emitting a laser beam (6) for irradiating the particulate sample (5) flowing through the flow cell in a carrier gas flow, a detector (8) for detecting light scattered or diffracted by the particulate sample, and processing means (28) for deriving a particle size distribution from the detected light. In order to disperse the particulate sample before it enters the measurement flow cell, the apparatus further comprises primary dispersion means (12,17a) providing a peripheral gas flow (30) converging on the flow axis, thereby generating a turbulent zone for dispersing the particulate sample, and secondary dispersion means (17b) downstream of the first dispersion means, said secondary dispersion means providing a lateral gas flow (31) intersecting the converging zone of the peripheral gas flow, thereby providing secondary dispersion of the particulate sample. Optionally, the apparatus further comprises means for providing a sheath flow (16) enveloping the particulate sample flow as it enters the flow cell. <IMAGE>
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