Method and apparatus for decorticating plant stalks

Abstract

Method and apparatus for decortication of plant stalks, involving flattening the plant stalk into two substantially planar stalk sides adjoined at their edges; splitting the two substantially planar stalk sides one from the other; bending the flat stalk piece with the hurd on the outside of the bend and bast on the inside of the bend; separating the segments such that the bast pulls away from the hurd and spans the gap between the two segments; bringing a stripper into abutment with the spanning bast and moving the stripper so as to draw the bast, which strips the bast away from the hurd; and removing the bast from the stripper.

1 . Apparatus for decorticating a piece of plant stalk having an outer bast and an inner hurd, the apparatus comprising:
 a) a splitter for splitting the piece of plant stalk lengthwise to create a plurality of plant stalk sections, each section having a bast side, a hurd side and two ends;   b) a bend member about which to make a bend in a one of the plant stalk pieces, with the hurd on the outside of the bend and bast on the inside of the bend, so as to break the hurd layer without severing the bast layer;   c) a turn member for moving along the bast from the vicinity of the bend member, thus causing a turn to move along the bast, separating the bast from the hurd as the turn passes, resulting in a portion of bast spanning a gap between the bend member and the turn member; and   d) a stripper member for passing through the gap between the bend member and the turn member, so as to fold the bast about the stripper member and draw the bast past the bend member and the turn member, so as to cause turns to move along the bast to the ends of the plant stalk section, thus separating the bast from the hurd as the turns pass.   
     
     
         2 . The apparatus of  claim 1 , further comprising an infeed assembly for flattening the piece of plant stalk and bringing the flattened piece of plant stalk into engagement with the splitter. 
     
     
         3 . The apparatus of  claim 1 , wherein the stripper member is a first stripper blade mounted at a first end of a rotatable beam and the first stripper blade is curved with a constant radius about an axis of rotation of the rotatable beam. 
     
     
         4 . The apparatus of  claim 1 , further comprising a second stripper blade mounted at a second end of the rotatable beam opposite the first stripper blade. 
     
     
         5 . The apparatus of  claim 1 , wherein the bend member comprises a movable draw bar. 
     
     
         6 . The apparatus of  claim 1 , further comprising an assembly for removing bast from the stripper member. 
     
     
         7 . The apparatus of  claim 6 , wherein the assembly for removing bast from the stripper member comprises a rotatable belt positioned so as to engage a leading edge of the stripper member about which the bast is folded. 
     
     
         8 . The apparatus of  claim 6 , wherein the assembly for removing bast from the stripper member comprises a shoe-type extractor.