A mixing silo for free-flowing finely divided solid materials, in particular for powdered, fibrous and/or granular mixed material, especially polymer granules, specifically suited for mixing polymer granules, having an excellent mixing quality and at the same time a simplified and improved suitability for washing out in order to avoid cross contamination. The mixing silo may be used for homogenizing possibly inhomogeneous polymer granule batches in the form of a stream of product from a process producing polymer granules.
1. A mixing silo comprising,
a cylindrical container, having a container wall and a conical outlet;
a plurality of curved partition walls vertically arranged in the cylindrical container, connecting a central middle pipe, running in the direction of the longitudinal axis of the cylindrical container, and the container wall to one another, wherein the plurality of curved partition walls and the container wall of the cylindrical container form a plurality of chambers, separated from one another, the plurality of chambers being fillable with granules from above and each chamber having an emptying opening at the conical outlet for removal of the granules, and wherein all the emptying openings open out into the conical outlet and the emptying openings cannot be closed off; and
a filling device configured to distribute the granules into each chamber.
2. The mixing silo according to claim 1 , further comprising one or more devices configured to flush regions of interior space of the mixing silo with liquid to remove remains of product from the mixing silo.
3. The mixing silo according to claim 2 , wherein the one or more devices for flushing are arranged fixed in place or in a flexible and telescopic manner.
4. The mixing silo according to claim 1 , wherein the filling device is of the rotary tube distributor type, is disposed centrally on a roof of the silo, and comprises a rotatable tube, having a length and curvature suitable for the mixing silo.
5. The mixing silo according to claim 4 , further comprising initiators configured to establish filling positions.
6. The mixing silo according to claim 1 , wherein a mixing space formed from below the chambers to a shut-off valve has a volume of at most 2% and at least 0.1% of a total volume of the silo, wherein the total volume of the silo is the sum of volumes of all chambers the mixing space.
7. The mixing silo according to claim 6 , wherein the mixing space volume is at most 1% and at least 0.2% of the total volume of the mixing silo.
8. Use of a mixing silo according to claim 1 , characterized in that polymer granules are filled into the silo chambers and the polymer granules are subsequently let out.
9. Use of a mixing silo according to claim 8 , characterized in that, after letting out the polymer granules, the chambers are flushed out.
10. The mixing silo according to claim 1 , wherein the plurality of curved partition walls is formed without acute angles between adjacent chamber walls.
11. The mixing silo according to claim 1 , further comprising segments positioned between each curved partition wall and the container wall to avoid the creation of acute angles between adjacent chamber walls.