Crushing/discharging device for materials being dried in a multistage type vacuum drying apparatus

A vacuum drying apparatus, comprising:

• an enclosure having an internal vacuum chamber;
• a plurality of endless conveyor belts disposed within said vacuum chamber, each of said conveyor belts having a substantially horizontal upper reach, said upper reach having a feed end and a discharge end, each of said conveyor belts having a lower return reach and return portions respectively connecting the opposite ends of said lower return reach to the feed end and discharge end of said upper reach, the upper reaches of said conveyor belts being substantially parallel with and vertically spaced from each other;
• supply means for feeding the material to be dried onto the upper surfaces of said upper reach of each of said conveyor belts near to the feed end thereof so that the material moves with said upper reach of said conveyor belt to the discharge end thereof;
• heating means associated with said upper reach of each of said conveyor belts for heating the material to assist in drying the material;
• a casing mounted adjacent to the discharge end of said upper reach of each of said conveyor belts;
• a crushing device disposed within each of said casings, said crushing device comprising a first, fixed, cutter blade extending longitudinally away from said discharge end of said upper reach and adapted for peeling off the material from said upper reach and directing it into said casing, said cutter blade having a multiplicity of transversely spaced-apart teeth on the end thereof remote from said discharge end of said upper reach of said conveyor belt, said crushing device also comprising a rotary cutter mounted for rotation about a substantially horizontal axis extending transversely to said upper reach of said conveyor belt, said rotary cutter comprising a multiplicity of substantially radially extending, axially spaced-apart cutting pins which are interdigitated with said teeth so that rotation of said rotary cutter crushes the material by moving said cutting pins through the interstices between said teeth;
• a screw conveyor disposed within each of said casings below said fixed cutter blade and said rotary cutter and adapted for receiving the crushed material, said screw conveyor being rotatable about a substantially horizontal axis that extends transversely to said upper reach of said conveyor belt, said screw conveyor having a helical screw flight for moving the crushed material in a direction transverse to said upper reach of said conveyor belt, said cutting pins being interdigitated with said screw flight so that said cutting pins move through the spaces between adjacent convolutions of screw flight so that the crushed material is smoothly and continuously moved into said screw conveyor.