Patent ID: 7571871

Claim:
A shear application system for applying substantially uniform amounts of shear to a powder sample, said shear application system comprising: a cylinder assembly, comprising: an inner cylinder having an external cylindrical surface; a housing having (i) an internal cylindrical surface concentric with said external cylindrical surface, said internal and external cylindrical surfaces forming an annular chamber therebetween, (ii) a cover, and (iii) a base, said housing configured to contain the powder sample within said annular chamber; and a plurality of projections extending from said external cylindrical surface and said internal cylindrical surface for imparting shear to the powder sample in said annular chamber, said projections extending from said external cylindrical surface forming a first set of gaps with said internal cylindrical surface, said first set of gaps having a first distance, said projections extending from said internal cylindrical surface forming a second set of gaps with said external cylindrical surface, said second set of gaps having a second distance substantially equal to said first distance, each one of said plurality of projections extending from said external cylindrical surface being spaced apart by a third distance from each one adjacent thereto of said plurality of projections extending from said internal cylindrical surface, said third distance being substantially equal to said first and second distances; drive means mechanically connected to said inner cylinder for inducing rotation of said inner cylinder in a direction of rotation; and control means electrically connected to said drive means for control thereof; wherein said projections extending from said external cylindrical surface have angled forward edges having leading edges facing in the direction of rotation.