Coand{hacek over (a)}-effect vegetable material dryer

An apparatus for drying vegetable material, the apparatus including:

• a drum defining an interior, the drum in operation rotating about its axis in sealed rotatable engagement between;
• a feed-end structure, the feed-end structure defining:
• an infeed hopper defining an infeed port for admitting vegetable material into the drum,
• an exhaust port through which, in operation, an exhaust blower draws an exhaust volume of heated air and dust from the interior of the drum, and
• a plenum through which an intake blower blows an intake volume of heated air into the drum for drying vegetable material, the intake volume selected not to exceed the exhaust volume, the plenum being in fluid communication with a nozzle, the nozzle opening in a rectangular slot extending in its longest dimension substantially the length of the drum, the plenum and nozzle being housed to form a Coand{hacek over (a)}-effect nozzle body having a tear-shaped housing, the housing comprising two Coand{hacek over (a)} surfaces situated in opposed relation and terminating at the nozzle, the Coand{hacek over (a)} surfaces to guide air to be entrained, in operation, with a jet of air issuing from the nozzle to form a combined flow;
• and
• a discharge-end structure defining a discharge chute for removing vegetable material from the interior of the drum;
• and
• the exhaust blower connected to blow the exhaust volume of heated air and dust into a cyclone separator, the cyclone separator allowing the heated air to escape to the ambient and to drop dust into the infeed hopper to mix with vegetable material as the vegetable material is admitted into the drum.

A method for drying vegetable material comprising:

• providing a drum defining an interior, wherein the drum further comprises a plurality of vanes within the interior extending radially into the drum, and extending axially substantially the length of the drum the drum driven, in operation, to rotate about its axis such that the plurality of vanes convey vegetable material from a lowest point in the interior of the drum to a highest point in the interior of the drum, there to drop the vegetable material from interspaces between the plurality of vanes downward within the interior of the drum situated in sealed rotatable engagement between;
• a feed-end structure, the feed-end structure defining:
• an infeed hopper defining an infeed port for admitting vegetable material into the drum,
• an exhaust port through which, in operation, an exhaust blower draws an exhaust volume of heated air and dust from the interior of the drum, and
• a plenum through which an intake blower blows an intake volume of heated air into the drum for drying vegetable material, the intake volume selected not to exceed the exhaust volume, the plenum being in fluid communication with a nozzle, the nozzle opening in a rectangular slot extending in its longest dimension substantially the length of the drum, the plenum and nozzle being housed to form a Coand{hacek over (a)}-effect nozzle body having a tear-shaped housing, the housing comprising two Coand{hacek over (a)} surfaces situated in opposed relation and terminating at the nozzle, the Coand{hacek over (a)} surfaces to guide air to be entrained, in operation, with a jet of air issuing from the nozzle to form a combined flow;
• and
• a discharge-end structure defining a discharge chute for removing vegetable material from the interior of the drum;
• rotating the drum;
• feeding vegetable material through the infeed hopper into the interior of the drum;
• blowing an intake volume of heated air into the plenum to form an escaping jet of escaping air having a rectangular cross-section extending substantially the length of the drum, the escaping jet entraining air in the interior of the drum into a Coand{hacek over (a)}-effect combined airflow;
• providing a hopper plate extending substantially the length of the drum, which in cooperation with the Coand{hacek over (a)}-effect nozzle body forms a hopper;
• catching, in the hopper, vegetable material dropping downward from the interspaces between the vanes within the interior of the drum, the hopper directing the caught vegetable material into the Coand{hacek over (a)}-effect combined airflow, the Coand{hacek over (a)}-effect combined airflow combining with the vegetable material to form an aerosol.