System and method for polishing capsules

1. A system for polishing capsules comprising:

an inlet;

an outlet;

a wall arranged around an axis (Z) extending from said inlet to said outlet;

a brush located at least partially inside the wall and comprising bristles arranged around said axis (Z) to form a helical conveying ramp for said capsules, from said inlet to said outlet,

each of said bristles comprising a free end facing an inner face of said wall; and

a mechanical unit configured to generate a rotational movement of said brush about said axis (Z) to convey said capsules from said inlet to said outlet;

wherein:

a distance between said axis (Z) and said free end of a first bristle of said brush, and a distance between said axis (Z) and said free end of a second bristle of said brush differ by at least 2 mm;

said system comprising at least one protrusion;

at said inner face of said wall, and arranged to bend at least some of said bristles of said brush during said rotational movement of said brush around said axis (Z).

2. The system according to claim 1 , wherein:

the first bristle configured to support said capsules;

said free end of said second bristle is configured to contact said capsules; and

said protrusion is configured to contact said capsules to influence a trajectory of said capsules during said rotational movement of said brush around said axis (Z).

3. The system according to claim 1 , wherein said bristles are arranged along straight line segments orthogonal to said axis (Z) to coincide with said straight line segments;

said straight line segments corresponding to cross sections of circular helicoids supported by said axis (Z), said cross sections being made along planes orthogonal to said axis (Z);

said circular helicoids having the same pitch and the same inner radius;

an outer radius of a first one of said helicoids differing by at least 2 mm from an outer radius of a second one of said helicoids.

4. The system according to claim 1 , wherein said free ends of said bristles included in a cross section of said brush along a plane comprising said axis (Z) are arranged along four to twenty straight lines parallel to said axis (Z), symmetrically aligned on said plane, on either side of said axis (Z);

a distance between said axis (Z) and a first one of said straight lines, and

a distance between said axis (Z) and a second one of said straight lines,

differing by at least 2 mm.

5. The system according to claim 1 , wherein said free ends of said bristles included in a cross section of said brush along a plane comprising said axis are substantially arranged along:

similar half ellipses of axes parallel and/or orthogonal to said axis (Z); and

along two straight lines parallel to said axis (Z), symmetrically aligned on said plane, on either side of said axis (Z).

6. The system according to claim 1 , wherein:

said wall is cylindrical and symmetrically arranged along said axis (Z);

said wall comprises:

a lower cylindrical section comprising an inlet opening mechanically coupled to said inlet, and

an upper cylindrical section surmounting said lower cylindrical section and comprising an outlet opening mechanically coupled to said outlet ( 3 B);

said inner face is cylindrical of radius R;

said system further comprising a central cylindrical portion arranged symmetrically along said axis (Z) and comprising a cylindrical outer surface of radius r <R;

each of said bristles of said brush comprising an end fixed to said central cylindrical portion.

7. The system according to claim 1 , wherein said wall comprises a plurality of sections mechanically coupled to each other, and in that said at least one protrusion comprises at least one protrusion section facing two of said sections, and fixed to at least one of said sections.

8. The system according to claim 1 , wherein in that said at least one protrusion comprises at least one protrusion portion fixed to an additional element configured to be mechanically coupled to said wall, so as to at least locally conform to a shape of said wall;

said at least one protrusion portion being configured to enter a passage passing through said wall when said additional element is mechanically coupled to said wall, so that said at least one protrusion portion is arranged at least partially inside said wall.

9. The system according to claim 8 , wherein:

the system comprises a suction unit adapted to evacuate dust from the inside of said wall;

said wall comprises at least one hole with a diameter capable of being strictly smaller than a diameter of said capsules;

said additional element comprises a conduit,

a first end of said conduit being mechanically coupled to a portion of said wall comprising said at least one hole,

a second end of said conduit being mechanically coupled to said suction unit;

said conduit being arranged to transport said dust.

10. The system according to claim 9 , wherein it further comprises at least one seal fixed to an inner face of said additional element, said at least one seal describing a curve on said inner face of said additional element, said curve being configured to locally conform to said shape of said wall, so as to surround an outer surface of said portion of said wall comprising said at least one hole, when said additional element is mechanically coupled to said wall.

11. The system according to claim 1 , wherein it further comprises:

a lower plate arranged perpendicularly to said axis (Z), mechanically coupled to said wall and to a lower end section of said brush;

said lower end section of said brush being configured to convey said capsules from said inlet to an upper section of said brush surmounting said lower end section of said brush during said rotational movement of said brush;

said upper section of said brush being configured to convey said capsules from said lower end section of said brush to said outlet during said rotational movement of said brush;

at least one lug at a surface of said plate bordering the inside of said wall, said lug being capable of driving at least one of said capsules from said plate to said lower end section of said brush, during said rotational movement of said brush.

12. The system according to claim 11 , wherein:

the system further comprises a suction unit configured to evacuate dust from the inside of said wall;

said plate comprises at least one orifice having a diameter smaller than a diameter of said capsules; and

said suction unit comprises a conduit mechanically coupled to said plate, said at least one orifice of said plate surmounting an opening of said conduit;

said conduit being configured to transport said dust.

13. The system according to claim 1 , further comprising:

an antistatic polymer tube mechanically coupled to said outlet and configured to convey said capsules from said outlet;

a detection unit mechanically coupled to said tube and configured to detect metal intoxication of said capsules as said capsules are conveyed through said tube.

14. A method of polishing capsules comprising the steps of:

(i) providing a system for polishing said capsules according claim 1 ;

(ii) generating a rotational movement of said brush around said axis (Z) with said mechanical unit;

(iii) introducing said capsules into said system through said inlet;

(iv) conveying said capsules from said inlet to said outlet on said conveying ramp formed by said brush in rotational movement around said axis (Z);

(v) discharging and collecting said capsules through said outlet.

15. A production line for capsules comprising the system for polishing said capsules according to claim 1 .