Abstract:

The invention relates to a rotary pelleting machine comprising a driveable die block provided with a defined number of dies distributed over the periphery thereof, bottom rams and top rams which are associated with the dies and rotate about a common rotational axis, synchronously with the die block, along a bottom ram guide and a top ram guide, at least one filler device for filling the dies with a material to be compressed, and a compression device for acting on the rams with a compression force. According to the invention, the filler device (18) comprises at least two independently chargeable filling chambers (24) which can be successively brought into a defined filling position. The invention also relates to a method for producing a multi-layer pellet by means of a rotary pelleting machine.

Claims:

1. Rotary pelleting machine with a driven die block having a defined number of dies distributed over a periphery of the die block, bottom plungers and top plungers associated with the dies and rotating along a bottom plunger guide and a top plunger guide about a common rotation axis synchronous with the die block, with at least one filling apparatus for filling the dies with a material to be pressed, and a pressing device for applying a pressing force to the plungers, characterized in that the filling apparatus (18) has at least two filling chambers (24) which can be filled independent of one another, wherein the filling chambers (24) can be moved sequentially to a defined filling position.

2. Rotary pelleting machine according to claim 1, characterized in that the filling chambers (24) can be moved in the filling position sequentially and continuously during the rotation of the die block (12).

3. Rotary pelleting machine according to claim 2, characterized in that the filling apparatus (18) has at least two sequentially accessible filling chambers.

4. Rotary pelleting machine according to claim 3, characterized in that the filling apparatus (18) is a rotatable chamber feed shoe (20) having at least two filling chambers (24).

5. Rotary pelleting machine according to claim 4, characterized in that the chamber feed shoe (20) has six filling chambers (24) which are arranged in star-shape about a rotation axis (22) of the chamber feed shoe (20).

6. Rotary pelleting machine according to claim 1, characterized in that the chamber feed shoe (20) is operatively connected with a drive which enables in combination a rotary and a linear motion.

7. Rotary pelleting machine according to claim 1, characterized in that a rotary drive of the chamber feed shoe (20) is a drive (48), a pneumatic drive and the like.

8. Rotary pelleting machine according to claim 1, characterized in that the pressing device (26) of the rotary pelleting machine (10) comprises a main pressure roller pair (30).

9. Rotary pelleting machine according to claim 8, characterized in that the pressure rollers (30) are arranged for height adjustment with respect to the die block (12).

10. Rotary pelleting machine according to claim 9, characterized in that the device for height adjustment comprises at least one drive (48), a pneumatic drive and the like.

11. Rotary pelleting machine according to claim 1, characterized in that the guide tracks (40, 42) for the bottom plungers and/or top plungers are height-adjustable relative to the die block.

12. Rotary pelleting machine according to claim 11, characterized in that segments of the guide tracks (40, 42) are height-adjustable independent of one another.

13. Rotary pelleting machine according to claim 11, characterized in that the height adjustment comprises at least one drive (48), a pneumatic drive and the like.

14. Rotary pelleting machine according to claim 1, characterized in that only a single plunger pair associated with the die (16) to be filled is provided.

15. Rotary pelleting machine according to claim 14, characterized in that additional dies (16) of the die block (12) are implemented as dummy dies.

16. Method for producing a multilayer tablet with a rotary pelleting machine , wherein the various layers and/or inserts are introduced in a die of a rotor and pressed, characterized in that the individual layers and/or inserts are introduced in the die sequentially in a continuous process at a common predefined filling position.

Description:

[0001]The invention relates to a rotary pelleting machine and method for producing a multilayer tablet.

[0002]Rotary pelleting machines are commonly known. A rotor of the rotary pelleting machine is set into rotation using a drive machine. The rotor includes dies arranged along a periphery which are associated with top plungers and bottom plungers. The dies are filled with a material to be pressed via at least one feed shoe and, depending on the angular position of the rotor, the bottom plungers and top plungers, which are guided via guide tracks, move axially with respect to the dies. The bottom and top plungers pass at least one pressing station, typically a pre-pressing station and a main pressing station. The top and bottom plungers are controllably guided past stationary pressure rollers, so that a pressing force can be applied to the material to be pressed introduced into the dies.

[0003]Rotary pelleting machines are known which can be used to produce so-called multilayer tablets, i.e., tablets containing several layers and/or inserts. Several feed devices and pressing stations are sequentially arranged along the periphery of the rotor. The rotor must therefore have a correspondingly large circumference which depends on the number of layers and/or inserts. Consequently, a rotary pelleting machine requires a large installation space.

[0004]Conventional rotary pelleting machines operate very inefficiently, in particular, when producing small quantities of multilayer tablets, for example in laboratory-type production setting or for tests pressings.

[0005]It is therefore an object of the invention to provide a rotary pelleting machine of the aforedescribed type and a method for producing a multilayer tablet, which can be used to produce multilayer tablets in a simple manner, and more particularly also in small quantities.

[0006]The object is attained with the invention with a rotary pelleting machine having the features recited in claim 1 and a method for producing a multilayer tablet with the features recited in claim 16.

[0007]Advantageously, a rotary pelleting machine for the production of multilayer tablets with a small footprint can be constructed by employing a filling apparatus with at least two filling chambers that can be filled independent of one another, wherein the filling chambers can be moved sequentially to a defined filling position, wherein preferably the filling chambers can be continuously and sequentially brought into the filling position during the rotation of the die block. A corresponding layer or an insert of the multilayer tablet can produced or brought into position during each complete revolution of the die block (rotor) by moving the filling chambers which can be filled independently of one another sequentially into the filling position. As a result, particularly the circumference of the die block can be reduced to the minimum dimension necessary to fill and press (optionally pre-press and main-press) the dies. This approach obviates the need for producing and positioning the layers and the inserts, respectively, sequentially during a revolution of the die block. The number of dies and plunger pairs is also reduced significantly. More particularly, such small-size rotary pelleting machine can be used as laboratory machines or test machines.

[0008]According to an advantageous embodiment of the invention, the filling apparatus includes several, i.e., at least two, sequential chambers which can be accessed individually (sequentially). The chambers are filled under production conditions. Filling and sequential addressing are hereby integrated into the temporal sequences of the overall process. Accordingly, one chamber is always brought into the filling position, thereby providing a continuous process flow.