Apparatus and methods for the comminution of botanical feedstock

1. An apparatus for the comminution of a botanical feedstock, the apparatus comprising:

(i) a vessel having a top and a bottom, the bottom comprising a first feedstock outlet;

(ii) a screen positioned in the vessel above the first feedstock outlet and spaced from the top of the vessel, the screen having an upper surface and a lower surface; and,

(iii) a blade rotatably mounted above and generally parallel to the screen and configured to be rotated in a direction of rotation, the blade having:

a) a radial blade length that extends in a radial direction between an axis of rotation of the blade and a blade tip;

b) a leading side, at least a portion of the leading side having a cutting edge; and

c) a trailing side in the direction of rotation, at least a portion of the trailing side having a downwardly extending trailing portion, the downwardly extending trailing portion having a lower edge that extends in the radial direction, the lower edge having a plurality of discontinuities,

wherein the cutting edge is spaced from the upper surface of the screen by a first distance and a lowermost portion of the lower edge is spaced from the upper surface of the screen by a second distance.

2. The apparatus of claim 1 , wherein the plurality of discontinuities comprises radially spaced apart downwardly extending sections of the lower edge, each section having a top and a bottom, wherein the radial extent of each section narrows towards the bottom of the section and a gap between adjacent sections increases towards the bottom.

3. The apparatus of claim 2 wherein the lower edge is generally saw toothed in shape.

4. The apparatus of claim 2 wherein the lower edge is generally sinusoidal in shape.

5. The apparatus of claim 1 wherein the first distance is from 31 mm to 54 mm.

6. The apparatus of claim 1 wherein the second distance is from 7 mm to 30 mm.

7. The apparatus of claim 1 wherein the screen has an aperture size of between 2 mm and 15 mm.

8. The apparatus of claim 1 wherein the vessel defines a volume overlying the blades and the volume is uninterrupted.

9. The apparatus of claim 1 further comprising a feedstock inlet in communication with the vessel and comprising an openable feed port.

10. The apparatus of claim 1 wherein the first feedstock outlet is connectable in fluid communication with a source of negative pressure.

11. The apparatus of claim 1 wherein the blade has a rate of rotation and at the rate of rotation, the downwardly extending trailing portion is operable to draw at least some feedstock positioned on the upper surface of the screen from the upper surface of the screen towards a plane of rotation of the cutting edge.

12. The apparatus of claim 11 wherein the downwardly extending trailing portion extends at an angle of between 30 degrees and 60 degrees to the plane of rotation.

13. The apparatus of claim 1 further comprising a cyclonic separator positioned downstream from the first feedstock outlet, the cyclonic separator being in flow communication with a separated material collection region and a fluid outlet.

14. The apparatus of claim 13 further comprising a filter positioned downstream from the fluid outlet.

15. The apparatus of claim 1 wherein the blade comprises a plurality of blades.