Apparatus for vaporizing a particulate material, comprising a metering apparatus including: a reservoir; a housing having an internal volume and first and second openings for respectively receiving and discharging the particulate material; a rotatable shaft disposed in the internal volume, the shaft...http://www.google.com/patents/US8101235?utm_source=gb-gplus-sharePatent US8101235 - Vaporization apparatus with precise powder metering
