Typical Design Data on ha, U, 
t, 
t, | Direct contact (convection) | |||
| ha | (t-tm)lm |  |
|
| Pneumatic conveyor | 2000~6000 | 70~200 | 40~60 |
| Rotary dryer | 100~400 | 80~300 | 40 ~60 |
| Through-circulation | 700~2000 | 40~60 | 45 ~60 |
| Tunnel dryer | 200~300 | 30~70 | - |
| Indirect contact (conduction) | |||
| U | (tk-tm)av | |
|
| Cylinder or drum dryer | 100~200 | 50~80 | 50~80 |
| Rotary dryer (heating tube) | 60~130 | 50~100 | - |
