Patent ID: 11872593
Assignee: AGT-USA, INC.
Field: Chemical engineering (Chemistry)
Classification: CPC B | IPC B

Claim 0:
1. 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 1 comprising a grinding mill 35 with an outlet to a sifting tray assembly 2, said sifting tray assembly comprising (a) an inlet end 12 with an inlet 7 for large particles and small particles, (b) a means 4 for separating the large particles from the small particles, (c) an outlet end 13 with an outlet 8 for discharge of the large particles and an outlet 5 for discharge of small particles, (d) a first container 44 in communication with the outlet for discharge of the large particles for collection of the large particles and (e) a second container 42 in communication with the outlet 5 for discharge of the small particles;
passing large particles and small particles through the grinding mill 35 and into the sifting tray assembly 2;
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 2 to separate the small particles from the large particles;
passing the large particles to the first container 44 and passing the small particles to a second container 42 or a second sifting tray assembly 2; and
drawing the gaseous cryogen from the particle separation system with a first pump 50;
operating the first pump 50 to force the gaseous cryogen through a filter means 49 to remove any small particles entrained in the gaseous cryogen drawn from the particle separation system.