Method and apparatus for dry particle analysis
First Claim
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1. A dry particle analyzer comprising:
- means for drizzling particles from a bulk sample thereof, means for providing a downward flow of first sheath ambient air around said drizzling particles in a flow regime of laminar bulk flow with a surrounding viscous boundary layer, means for suddenly changing the flow regime of said drizzling particles and first sheath air to a flow regime with a surrounding second sheath of high velocity air causing high shear and acceleration of said drizzling particles and first sheath air flow and with admixture of said second sheath air, means for columnating and decelerating said particles and said admixture of first sheath air and second sheath air, means for providing a downward and columnar flow of third sheath ambient air around said columnated drizzled particles and first and second air flows admixed together and substantially in velocity union therewith, and means defining a vertically downwardly extending optical analysis cell passage receiving the unified downward flow of drizzled particles and admixed first and second sheath air surrounded by said third sheath air for columnated downward flow therein, whereby the drizzled particles flow downwardly continuously from said bulk sample and through said analysis cell passage.
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Abstract
A dry particle analyzer includes a vibrating sieve cup drizzling particles downwardly with first, second, and third sheath air flows being provided to separate the particles from boundary walls and to form the drizzling particles into a columnated flow for optical analysis. The particles drop vertically as a drizzle with gravitational assistance from a bulk sample to an analysis chamber. Along the way to the analysis chamber, the particles are subjected to an interval of high air flow shear, and to high turbulence of the air flow to break up agglomerations of particles.
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Citations
22 Claims
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1. A dry particle analyzer comprising:
- means for drizzling particles from a bulk sample thereof, means for providing a downward flow of first sheath ambient air around said drizzling particles in a flow regime of laminar bulk flow with a surrounding viscous boundary layer, means for suddenly changing the flow regime of said drizzling particles and first sheath air to a flow regime with a surrounding second sheath of high velocity air causing high shear and acceleration of said drizzling particles and first sheath air flow and with admixture of said second sheath air, means for columnating and decelerating said particles and said admixture of first sheath air and second sheath air, means for providing a downward and columnar flow of third sheath ambient air around said columnated drizzled particles and first and second air flows admixed together and substantially in velocity union therewith, and means defining a vertically downwardly extending optical analysis cell passage receiving the unified downward flow of drizzled particles and admixed first and second sheath air surrounded by said third sheath air for columnated downward flow therein, whereby the drizzled particles flow downwardly continuously from said bulk sample and through said analysis cell passage.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A dry particle analyzer apparatus comprising:
- means for providing a cloud of drizzled particles gravitationally descending in a relatively low-velocity laminar bulk flow of surrounding ambient first sheath air with a surrounding low-velocity viscous boundary layer, and a de-agglomerator for affecting attrition of agglomerations of said particulates, said de-agglomerator including;
a Coanda type aspirator defining an opening through which said bulk flow of drizzled particles and first sheath ambient air is received, said aspirator receiving pressurized air and defining an annular radial gap surrounding said opening and from which a high-velocity second sheath air flow is discharged axially of said opening, thereby to apply a sudden high air flow shear to said particles and first sheath air flow. - View Dependent Claims (17, 18, 19, 20)
- means for providing a cloud of drizzled particles gravitationally descending in a relatively low-velocity laminar bulk flow of surrounding ambient first sheath air with a surrounding low-velocity viscous boundary layer, and a de-agglomerator for affecting attrition of agglomerations of said particulates, said de-agglomerator including;
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21. A method of de-agglomerating particles for optical dry particle analysis, said method comprising steps of:
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drizzling particles from a bulk sample thereof; providing a downward flow of first sheath ambient air around said drizzling particles in a flow regime of laminar bulk flow with a surrounding viscous boundary layer; suddenly changing the flow regime of said drizzling particles and first sheath air to a flow regime with a surrounding second sheath of high velocity air; using said second sheath of high velocity air to cause high shear and acceleration of said drizzling particles and first sheath air flow; effecting admixture of said second sheath air with said first sheath air; columnating and decelerating said particles and said admixture of first sheath air and second sheath air; providing a downward and columnar flow of third sheath ambient air around said columnated drizzled particles and admixed first and second sheath air flows and substantially in velocity union therewith; and receiving the unified downward flow of drizzled particles and admixed first and second sheath air surrounded by said third sheath air into a vertically downwardly extending optical analysis cell passage for columnated downward flow therein. - View Dependent Claims (22)
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Specification