Rotary reactor for uniform particle coating with thin films
A reactor for coating particles includes one or more motors, a rotary vacuum chamber configured to hold particles to be coated, wherein the rotary vacuum chamber is coupled to the motors, a controller configured to cause the motors to rotate the rotary vacuum chamber about an axial axis of the rotary vacuum chamber such that the particles undergo tumbling agitation, a vacuum port to exhaust gas from the rotary vacuum chamber, a paddle assembly including a rotatable drive shaft extending through the rotary vacuum chamber and coupled to the motors and at least one paddle extending radially from the drive shaft, such that rotation of the drive shaft by the motors orbits the paddle about the drive shaft in a second direction, and a chemical delivery system including a gas outlet on the paddle configured inject process gas into the particles.
1. A method for coating particles, comprising:
dispensing particles into a rotary vacuum chamber;
rotating the rotary vacuum chamber along an axial axis of the rotary vacuum chamber in a first direction, comprising maintaining a particle bed formed by a portion of the particles dispensed within the rotary vacuum chamber that remain in a lower portion of the rotary vacuum chamber;
evacuating the rotary vacuum chamber through a vacuum port in the rotary vacuum chamber
rotating a paddle assembly in a second direction such that a plurality of paddles orbit a drive shaft; and
injecting a process gas into the particles through a plurality of gas outlets located on the plurality of paddles wherein, continuously as the plurality of paddles orbit the drive shaft, at least one paddle of the plurality of paddles extends into the particle bed such that at least one gas outlet of the plurality of gas outlets is located within the particle bed formed by the particles to percolate the process gas through the particles held within the rotary vacuum chamber.
2. The method of claim 1 , wherein injecting the process gas into the particles through the plurality of gas outlets further comprises delivering the process gas via chemical supply passages located within the paddle assembly.
3. The method of claim 2 , wherein the chemical supply passages deliver the process gas through a base shaft and plate portion of one or more paddles of the plurality of paddles.
4. The method of claim 1 , wherein the vacuum port is aligned on the axial axis of the rotary vacuum chamber.
5. The method of claim 1 , wherein rotating the rotary vacuum chamber along the axial axis of the rotary vacuum chamber in the first direction comprises:
rotating a cylindrical portion of the rotary vacuum chamber at a rotation speed less than a threshold rotational speed such that a portion of the particles dispensed within the rotary vacuum chamber provide a particle bed that remains in a lower portion of the rotary vacuum chamber.
6. The method of claim 5 , wherein rotating the rotary vacuum chamber along the axial axis of the rotary vacuum chamber in the first direction comprises:
rotating the cylindrical portion of the rotary vacuum chamber at a rotation speed such that the particles undergo tumbling agitation.
7. The method of claim 6 , wherein the rotation speed is about 6-15 RPM.
8. The method of claim 1 , wherein rotating the rotary vacuum chamber along the axial axis of the rotary vacuum chamber in the first direction comprises:
rotating a cylindrical portion of the rotary vacuum chamber at a rotation speed greater than a threshold rotational speed such that the particles form a toroidal bed of particles on an inner wall of the rotary vacuum chamber.
9. The method of claim 8 , wherein at least one of the plurality of gas outlets is located on a portion of a paddle of the plurality of paddles within the toroidal bed of particles as the plurality of paddles orbit about the drive shaft.
10. The method of claim 8 , wherein the rotation speed is greater than 15 RPM.
11. The method of claim 10 , wherein a rotation speed of the drive shaft relative to the rotary vacuum chamber about the axial axis is at least 4 rpm.
12. The method of claim 1 , comprising coating the particles by atomic layer deposition or molecular layer deposition.
13. The method of claim 1 , comprising coating the particles by initiated chemical vapor deposition.
14. The method of claim 1 , wherein the particles comprise an active pharmaceutical ingredient.
15. The method of claim 12 , wherein the particles comprise a core containing a drug.
16. The method of claim 1 , further comprising depositing an organic or inorganic coating over the particles.
17. The method of claim 16 , wherein the organic or inorganic coating comprises an inorganic metal oxide.
18. The method of claim 16 , wherein the organic or inorganic coating comprises an organic polymer.
19. The method of claim 1 , wherein the first direction is opposite of the second direction.