| Popis: |
Fans are essential for effective air mixing and ventilation in poultry housing. Although performance data useful in selecting or comparing fans can be measured by qualified testing services, onsite measurements of fan speed and power use are also useful in evaluating operation of a given fan. In order to assess variation in fan operation, fan speed and power consumption were measured on thirty-five poultry farms in North Carolina. Both belt and direct drive fans up to 5 yr in age ran at nearly rated speeds. As fan age increased, variability in fan speeds of older fans increased due to factors such as variation in fan maintenance and fan and motor quality. Belt wear alone reduced the speed of one fan by over 20%, even though the worn belt appeared to have the proper tension. Since fan airflow rate is proportional to fan speed, the timely replacement of fan belts is essential and measurement of fan speed may be necessary to diagnose ventilation problems. The fans consumed considerably more power than their nominal power rating, so appropriate adjustments must be made to predict fan energy costs accurately. |
