A blower fan is a powerful electric machine that provid […]
A blower fan is a powerful electric machine that provides ventilation or air circulation for appliances or buildings that need air flow. A blower fan might be as small as the matchbook-size device in a laptop used to keep the processor cool or as large as a truck, installed in a large factory to provide ventilation.
The flow and pressure properties are the main differences between a fan and a blower. While fans deliver air in an overall direction that is parallel to the fan blade axis, blowers deliver air in a direction that is perpendicular to the blower axis. Hence, fans can be configured to deliver a high flow rate, working against low pressure while blowers to deliver a relatively low flow rate against high pressure. Centrifugal blowers can be squirrel cage type, have a forward curved wheel or a backward curved wheel.
Another major difference is in the mechanism regarding restriction to the air-flow. In a blower, it has an opposite effect on the same motor driving a fan blade. For instance, the load on the motor decreases when the motor is driving a squirrel cage blower. As the system becomes clogged, the blower speeds up. On the other hand, the load on the motor increases and the fan slows down as the airflow system becomes clogged with fan blades.
Very common as exhaust fans in industrial and commercial buildings, blower fans have become more prevalent in residences. More and more frequently, home builders and home owners have looked to conserve energy, making homes as airtight as possible. Homeowners insulate walls and attics, seal cracks and holes, wrap their homes in house wrap and install weather-tight doors and windows to conserve energy and prevent expensive loss of heat or cooling air. These energy-saving tactics, however, greatly reduce home air quality. Thus, blower fans have been introduced to provide improved home air ventilation, to supply a regular supply of fresh air and to exhaust heat from the home during hot weather.