Overview
The Forced Draft Tray Dryer uses an electric heater and blower to circulate hot air at controlled velocity across multiple trays of wet solid material. Forced convection significantly accelerates drying compared to natural draft and allows study of the effect of air velocity, temperature, and humidity on drying rates. Students measure moisture loss at timed intervals to plot drying curves and rate curves, determine critical moisture content, and calculate the drying constant in the falling rate period. The apparatus simulates industrial hot air dryers used in food dehydration, pharmaceutical granule drying, and ceramic drying.
Specifications
| Number of trays | 4 to 8 |
| Temperature range | ambient to 150 degrees C |
| Air velocity | 0.5 to 3 m/s |
| Blower | centrifugal with speed control |
| Temperature controller | PID |
| Weighing | online load cell or manual balance |
| Heater | electric, 1 to 3 kW |
| Power supply | 220V AC, 50 Hz |