The rotor closing the bottom of the filling chamber has eight dosing holes. From the center of the wheel, dosing pistons, which determine the filling volume, are threaded into these holes. The rotor is periodically rotated by 1/8 of its volume after each cycle, the dosing holes are set above the filling chamber, and the powder is sucked into the holes under vacuum. After two cycles, the outer surface of the filling wheel is cleaned with a doctor and the excess powder is sucked off. Two further cycles bring the rotor into alignment with the neck opening of the prepared vial. The powder is discharged into the bottle by a short pulse of compressed air. Bosch is developing a new generation of sterile powder dispensing machines with a key feature in the dosing module. The machine’s dust-tight protection allows air conditioning (temperature and humidity control) in the dosing and capping areas. Due to its compactness, the machine can be equipped with an isolator.

The central unit of AFG machines is a dosing unit using the vacuum and compressed air principle. With this dosing principle, the widest range of powders can be processed without dust formation and with great precision. Using vacuum, the powder is sucked into the dosing chamber and then blown back into the vial using sterile compressed air. After each dosing, the chamber is cleaned with sterile compressed air. Like all other parts of the machine in contact with the product, the dosing wheel is very easy to sterilize. Using a patented system, the dosing wheel can be replaced directly during the production of a single batch with complete sterility and without spilling powder from the feed hopper. In the feed hopper, the powder is stirred continuously by means of an agitator. The dosing accuracy depends on the filling volume and the properties of the powder. With the vacuum dosing method it is 1.5 % of the dosing volume. Machine for dispensing sterile powders. The dosing accuracy with the vacuum method is 2-3 times higher than with other technologies such as screw dosing.