We describe a quantitative, non-invasive capacitance detector providing a rapid signal that varies continuously with powder level and/or mass holdup in the metal feed tube of a tablet press. We outline the principle of its processing electronics, provide an algorithm for the accurate interpretation of its signals, pose general design guidelines for embedding the instrument in the tube, and show how the detector can be paired with another non-invasive reference probe to operate with varying powder blend and moisture. We illustrate a control strategy that keeps powder level constant with a process example.

• Cornell University
• Merck & Co., Inc

• PAT
• Oral solid dose

1. Capacitance instrumentation
2. Continuous pharmaceutical processing
3. Level control
4. Level sensor
5. oral solid dose
6. Other
7. pat
8. Powder moisture measurement