Screw feeder with multiple concentric flights
First Claim
1. A screw feeder for particulate solids having, in combination,a chamber having an end wall and wall portions extending downwardly and terminating laterally at said end wall,a cylindrical feed tube external to the chamber and communicating therewith through an opening in said end wall, the feed tube extending from said end wall to a discharge opening,feed screw means comprising coaxial helical inner and outer flights of differing outer diameters, each flight extending from within the chamber through said opening and the feed tube to the discharge opening, the outer flight being confined by the feed tube with a minimum nonbinding clearance, andmeans to rotate the flights in directions whereby one flight feeds the solids in the direction from the chamber toward the discharge opening and the other flight tends to feed the solids in the opposite direction.
1 Assignment
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Accused Products
Abstract
A compound screw feeder for uniform volumetric flow rates of particulate solids, suitable for low, nonpulsating feed rates, comprises coaxial inner and outer screw flights. The flights both extend throughout the feeder section and produce a net discharge flow rate dependent on their respective feed directions and rates of feed. Various forms of the feeder may be employed in a loss of weight screw feeder system.
73 Citations
14 Claims
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1. A screw feeder for particulate solids having, in combination,
a chamber having an end wall and wall portions extending downwardly and terminating laterally at said end wall, a cylindrical feed tube external to the chamber and communicating therewith through an opening in said end wall, the feed tube extending from said end wall to a discharge opening, feed screw means comprising coaxial helical inner and outer flights of differing outer diameters, each flight extending from within the chamber through said opening and the feed tube to the discharge opening, the outer flight being confined by the feed tube with a minimum nonbinding clearance, and means to rotate the flights in directions whereby one flight feeds the solids in the direction from the chamber toward the discharge opening and the other flight tends to feed the solids in the opposite direction.
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12. A screw feeder for particulate solids having, in combination,
a chamber having an end wall and wall portions extending downwardly to a trough, the lower portion of the trough conforming to a cylindrical sector, said trough terminating at said end wall, a cylindrical feed tube external to the chamber, having substantially the same inside diameter as said sector and being coaxial therewith, the trough and one end of the feed tube communicating through an opening in the end wall, the feed tube extending from said end wall to a discharge opening, feed screw means comprising coaxial helical inner and outer flights of differing outer diameters, each flight extending from within the trough through said opening and the feed tube to the discharge opening, the outer flight being confined by the feed tube with a minimum nonbinding clearance, and means to rotate the flights in directions whereby one flight feeds the solids in the direction from the chamber toward the discharge opening and the other flight tends to feed the solids in the opposite direction.
Specification