Process and apparatus for separating sand from botanical materials

Abstract

Apparatus is provided for the separation of sand and botanical materials, particularly tobacco, the apparatus including a fluidized bed and a porous support for the mixture of sand and botanical materials. The method incorporates the apparatus and aids in the separation, the method potentially including a pulsed fluid flow superimposed on a steady fluid flow in the system.

I claim: 
     
       1. An apparatus for the dry separation of sand particles from botanical fines in which substantially all of the sand particles and fines have a size which .[.is less than.]. .Iadd.will be retained on .Iaddend.about .Iadd.a .Iaddend. 100 mesh .Iadd.screen .Iaddend.comprising a. a substantially enclosed chamber;   b. supports means positioned at the bottom of said chamber for permitting the discharge of sand from said chamber, said support means including a plurality of substantially spherical bodies having a diameter of 2 to 5 mm and a tolerance of ±20 percent and constrained into substantially 3-center close packing;   c. first means for supplying a mixture of sand and botanical fines having a size .[.less than.]. .Iadd.which will be retained on .Iaddend.about .Iadd.a .Iaddend.100 mesh .Iadd.screen .Iaddend.into said chamber above said support means;   d. second means for moving an upwardly flow of gas through said support means into said chamber at a steady velocity sufficient to fluidize the mixture of sand and botanical fines above the support means; and   e. vibrating means for vibrating said support means.   
     
     
       2. The apparatus of claim 1 in which a third means superimposes a pulse flow on a steady flow of gas having a velocity of 1.2 to 41 feet per second. 
     
     
       3. The apparatus of claim 2 in which said third means superimposes the pulse flow at a velocity of 15 to 88 feet per minute for a pulse duration of 0.5 to 10 seconds and at a pulse frequency of one-half to sixty per minute. 
     
     
       4. The apparatus of claim 1 having a baffle means positioned within the chamber and adjacent the center of said support means for directing the air flow away from the center of said column.