Blower
Fans
Fans utilize power from a motor to generate
a volumetric flow of air at a given pressure, and are considered
low-pressure air pumps more often than not. A propeller converts
torque (turning force) from the motor (typically permanent
split capacitor AC induction motors or brushless DC) to increase
static pressure across the fan rotor and to increase the kinetic
energy of the air particles.
Fans are classified into propeller, tube axial and vane axial
styles, and each type has different characteristics. Propeller
fans consist of only a motor and propeller and therefore are
the simplest. Tube axial are similar to propellers but has
a venturi around the propeller to reduce the vortices. Vane
axial fans are equipped with vanes that trail behind the propeller
in the airflow to straighten the swirling flow.
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.
Blowers provides detailed information about blowers, backpack
blowers, blower fans, blower motors and more. Blowers is the
sister site of Electric Pressure Washers.
Article Source: http://EzineArticles.com/?expert=Ken_Marlborough
|