Apparatus for solids blending
First Claim
1. A particulate solids blending apparatus comprising, in combination, a vessel containing a settled bed of particulate solids to be blended consisting of an upright top section to which is joined a funnel type bottom section, a draft tube vertically disposed with respect to said top section with lower end in open communication with said funnel type bottom section and upper end in open communication with the top of said top section, means fluidizing a well-mixed fraction of about 0.01 to 0.20 of said solids in the region adjacent said lower end of said draft tube, means entraining solids upwardly through said draft tube, and solids flow-constricting means spaced inwardly from the inside wall of said upright top section disposed in the gravity flow paths of solids contained within said bed maintaining different residence times of separate weight fractions of said solids within said settled bed having residence time ratios in the range of about 1.5 to 5.0 while withdrawing said solids in downward gravity flow from said settled bed to said region adjacent said lower end of said draft tube provided with said means fluidizing solids.
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Accused Products
Abstract
Apparatus for the blending of a bed of particulate solids operating cyclically by selectively regulated downward gravity flow of a fraction of the solids, fluidized mixing outside of the bed, followed by recycle to the top of the bed.
22 Citations
10 Claims
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1. A particulate solids blending apparatus comprising, in combination, a vessel containing a settled bed of particulate solids to be blended consisting of an upright top section to which is joined a funnel type bottom section, a draft tube vertically disposed with respect to said top section with lower end in open communication with said funnel type bottom section and upper end in open communication with the top of said top section, means fluidizing a well-mixed fraction of about 0.01 to 0.20 of said solids in the region adjacent said lower end of said draft tube, means entraining solids upwardly through said draft tube, and solids flow-constricting means spaced inwardly from the inside wall of said upright top section disposed in the gravity flow paths of solids contained within said bed maintaining different residence times of separate weight fractions of said solids within said settled bed having residence time ratios in the range of about 1.5 to 5.0 while withdrawing said solids in downward gravity flow from said settled bed to said region adjacent said lower end of said draft tube provided with said means fluidizing solids.
- 2. A particulate solids blending apparatus comprising, in combination, a vessel containing a settled bed of particulate solids to be blended consisting of an upright cylindrical top section to which is joined an inverted frusto-conical bottom section, a draft tube disposed substantially coaxially with respect to said cylindrical section with lower end in open communication with said frusto-conical bottom section and upper end in open communication with the top of said cylindrical section, means fluidizing a well-mixed fraction of about 0.01 to 0.20 of said solids in the region adjacent said lower end of said draft tube, means entraining solids upwardly through said draft tube, and solids flow-constricting means spaced inwardly from the inside wall of said upright top section disposed in the gravity flow paths of solids contained within said bed maintaining different residence times of separate weight fractions of said solids within said settled bed having residence time ratios in the range of about 1.5 to 5.0 while withdrawing said solids in downward gravity flow from said settled bed to said region adjacent said lower end of said draft tube provided with said means fluidizing solids.
Specification