The process
Withering troughs blow a large volume of ambient or warmed air through green leaf for hours. The trough fan is an axial fan at low pressure, often with a hot air mixer, run for long hours and cleaned often.
The gas
Warm, humid air through withering troughs and dryers with light leaf dust. Large volume at low pressure; the fan is cleaned often, so access matters.
Fans in this process
| Duty | What it does here | Type usually selected |
|---|---|---|
| Trough Fan | Blows a large volume of ambient or warmed air through the bed of green leaf on a withering trough. | Axial |
| Hot Air Fan | Circulates or supplies air at elevated temperature to a dryer, oven or kiln. | Backward curved and backward inclined |
| Ventilation Fan | Moves air through a plant or building for fresh air supply, heat removal and fume dilution where the system is ducted. | Backward inclined and forward curved |