(1) Single-paddle powder feeder:
Improves filling compared to a gravity feeder, with a minimum of energy input.
(2) Vibra-fluid feeder:
A vibratory device improves the flow of difficult powders.
(3) Gravity feeder:
For fragile powders, the gravity feeder can be the best option.
(4) Small-dosage feeder:
To avoid feeder jamming, a very precise measurement of the powder level in the feeder triggers the powder in-feed.
(5) Powder dosing valve or PDV:
Presses are often fed from IBCs or silos. As these run empty, the powder pressure in the press feeder and hence the die varies, resulting in tablet weight variations. The tablet weight control system on the press or the operator can adjust the die fill, but the PDV is a much easier way to keep the feeder pressure constant. A sensor detects the powder level in a transparent tube and controls the motor of the powder scraper. When the scraper does not rotate the powder flow stops. In addition to keeping the powder pressure constant, the PDV prevents powder segregation. Another advantage is that the PDV can be used with abrasive powders.