Cryogenic Processing System for Plant Material

A method of separating small particles from plant stock, wherein said plant stock comprises large particles and small particles, said method comprising the steps of:

• providing a particle separation system comprising a sifting tray assembly comprising (a) an inlet end with an inlet for large particles and small particles, (b) a means for separating the large particles from the small particles, (c) an outlet end with an outlet for discharge of the large particles and an outlet for discharge of small particles, (d) a first container in communication with the outlet for discharge of the large particles for collection of the large particles and (e) a second container in communication with the outlet for discharge of the small particles;
• passing large particles and small particles into the sifting tray assembly;
• injecting a cryogen at cryogenic temperature into the particle separation system to cool the plant stock to cryogenic temperatures to solidify the small particles, wherein, at least after injection, the cryogen comprises a gaseous cryogen;
• operating the sifting tray assembly to separate the small particles from the large particles;
• passing the large particles to the first container and passing the small particles to a second container;
• and
• drawing the gaseous cryogen from the particle separation system with a first pump;
• and
• operating the first pump to force the gaseous cryogen through a filter means to remove any small particles entrained in the gaseous cryogen drawn from the particle separation system.

A method of separating small components from larger components of plant stock comprising, said method comprising:

• providing a sifting system for separating small components from larger components of plant stock comprising;
• a plurality of sifting tray assemblies, including at least a first sifting tray assembly and a second sifting tray assembly, wherein each sifting tray assembly comprises:
• an upper enclosure with an inlet aperture located at a first, inlet end of the upper enclosure, and a large particle outlet aperture located at a second, outlet end of the upper enclosure;
• a sifting screen below the upper enclosure
• a cryogen injector disposed proximate the first end of the upper enclosure, said cryogen injector configured to supply a cryogenic fluid to plant stock entering the upper enclosure 6;
• a bottom pan with a first end and a small particle outlet aperture located at a second end of the bottom pan, and a top open to the sifting screen, and a bottom with a closed surface;
• wherein the sifting screen is disposed between the upper enclosure 6 and bottom pan;
• a filter system in fluid communication with the sifting system, said filter system comprising
• a first pump for drawing cryogenic fluid from the sifting system;
• a filter for filtering any small particles entrained in the cryogenic fluid drawn from the sifting system and forced through the filter by the first pump;
• and performing the steps of:
• depositing plant stock into a first sifting tray assembly, through upper enclosure with an inlet aperture located at a first, inlet end;
• and
• vibrating the first sifting tray assembly to (1) separate a first population of small particles from the larger particle of the plant stock in the first tray, and (2) cause or facilitate movement of the larger plant stock particles downwardly, over the sifting screen and within the upper enclosure and toward the large particle outlet aperture 8 of the first sifting tray assembly, and (3) cause or facilitate movement of a first population of small particles downwardly within the pan bottom of the first sifting tray assembly toward the small particle outlet aperture 5 of the first sifting tray assembly, and
• spraying cryogen, using a cryogen injector of the first sifting tray assembly, over the plant stock within the first sifting tray assembly, or within the inlet or outlet tube 15 of the first sifting tray assembly while vibrating and moving the stock toward the outlet apertures of the first sifting tray assembly,
• passing the first population of small particles from the first sifting tray assembly to a second sifting tray assembly;
• vibrating the second sifting tray assembly to (1) separate a second population of small particles from the first population of small particles in the second sifting tray assembly, and (2) cause or facilitate movement of the larger plant stock particles downwardly, over the sifting screen and within the upper enclosure and toward the large particle outlet aperture 8 of the second sifting tray assembly, and (3) cause or facilitate movement of a second population of small particles downwardly within the bottom pan of the second sifting tray assembly toward the small particle outlet aperture 5 of the second sifting tray assembly, and
• spraying cryogen, using a cryogen injector of the second sifting tray assembly, over the plant stock within the second sifting tray assembly, or within the inlet or outlet tube of the second sifting tray assembly while vibrating and moving the stock toward the outlet apertures of the second sifting tray assembly,
• passing the second population of small particles from the second sifting tray assembly;
• drawing the gaseous cryogen from the sifting system with a first pump;
• and
• operating the first pump to force the gaseous cryogen through the filter to remove any small particles entrained in the gaseous cryogen drawn from the sifting system.