Device for capacitively measuring the powder fill level in a filling apparatus of a rotary press

A rotary press comprising:

• a rotor configured to be rotated by a rotary drive, wherein the rotor comprises,
• an upper punch guide,
• a lower punch guide, and
• a die plate defining a plurality of cavities and positioned between the upper punch guide and the lower punch guide;
• a plurality of upper punches configured to be guided by the upper punch guide;
• a plurality of lower punches configured to be guided by the lower punches, wherein
• the plurality of upper and lower punches interact with the plurality of cavities of the die plate;
• at least one upper pressing apparatus and at least one lower pressing apparatus;
• a filling apparatus configured to dispense a powder material to be pressed into the plurality of cavities of the die plate, wherein the filling apparatus comprises a filling pipe extending along a longitudinal axis, and wherein the at least one upper pressing apparatus and the at least one lower pressing apparatus are configured to interact with the plurality of upper punches and the plurality of lower punches to press the powder material in the cavities of the die plate;
• an ejection apparatus configured to eject pellets generated in the cavities;
• a device for capacitively measuring a fill level of the powder material in the filling apparatus, the device comprising,
• an electrically non-conductive holding portion positioned on the filling pipe,
• a first measuring electrode supported by the electrically non-conductive holding portion and extending along the longitudinal axis, the first measuring electrode configured to form a first electrical capacitor with a reference electrode that extends along the longitudinal axis, wherein an electrical field is configured to be formed between the first measuring electrode and the reference electrode,
• wherein the first measuring electrode is covered by an electrically conductive protective shielding on a side facing away from the filling pipe, and wherein the electrically conductive protective shielding is maintained at a ground potential, and
• a second measuring electrode positioned on the filling pipe and extending along the longitudinal axis,
• wherein the second measuring electrode extends over no more than 15% of a length of the first measuring electrode and is positioned in a region of a lower end of the first measuring electrode,
• wherein the second measuring electrode and the reference electrode form a second electrical capacitor,
• wherein an electrical field is configured to be formed between the second measuring electrode and the reference electrode, and
• wherein a measuring region of the second measuring electrode is covered by the powder material located in the filling pipe during operation of the rotary press.