|Pipe Diameter (in)||Cross1Area (ft2)||Airflow (cfm)2|
|1. Cross sectional area of inside air duct, not necessarily circular.|
|2. Airflow through duct in cfm = A x v|
Most aeration systems are designed with downward airflow through the cottonseed. This helps minimize moisture condensation and accumulation in the top layers of cottonseed, which can occur when warm, moist air moves upward into the cold top layers of seed. In addition, temperature and odor of the exhaust air from the fan can give an indication of cottonseed condition.
To select a fan, the required volume of air to aerate the number of tons of seed must be known as well as the static pressure. Static pressure or resistance to air flow is measured in inches of water and depends on the depth and density of the seed. Static pressures for different airflow rates and cottonseed depths are shown in Table 3. Knowing airflow and static pressure, a fan and motor can be selected from a supplier's catalog to meet the design specifications.