US Patent 7652247 Aerodynamic lens

An aerodynamic lens, comprises a cylindrical body having an inlet and an outlet; and a convergence-divergence lens portion inside the cylindrical body, having a lens hole formed at the center of the convergence-divergence lens portion, through which a carrier gas and particles pass, a convergence slant surface at a convergence angle (α) with a central axis of the aerodynamic lens at the front of the lens hole, and a divergence slant surface at a divergence angle (β) with the central axis of the aerodynamic lens at the rear of the lens hole.