Fan (implement)

Fan (implement)

A fan is a device used to create flow within a fluid, typically a gas such as air. The fan consists of a rotating arrangement of vanes or blades which act on the air. The rotating assembly of blades and hub is known as an impeller, rotor, or runner. Usually, it is contained within some form of housing or case. This may direct the airflow or increase safety by preventing objects from contacting the fan blades.

History

The earliest known fans date back to around 3000 BC during the Ancient Egyptian era. The Egyptians used fans as ceremonial devices that were waved over the Pharaoh to keep him cool. The Chinese also have a long history with fans and used them as decorative devices as well as cooling mechanisms. The folding fan was invented in Japan, with date ranging from the 6th to 9th centuries.

Types of Fans

There are many different types of fans, including: axial, centrifugal, cross-flow, and bladeless fans. Each type of fan has its own applications and uses, which can range from cooling electronics to moving air in HVAC systems.

Axial-flow Fans

Axial-flow fans are designed to move air in a direction parallel to the axis of rotation. They are used in a variety of applications, including air conditioning systems, industrial ventilation, and in wind tunnels.

Centrifugal Fans

Centrifugal fans use the kinetic energy of the rotating impellers to increase the volume of the air stream, which in turn moves against the resistance caused by ducts, dampers, and other components.

Cross-flow Fans

Cross-flow fans are often used in air conditioning systems. They are characterized by their cylindrical shape and the way they direct air perpendicular to the air intake.

Bladeless Fans

Bladeless fans, popularized by the company Dyson, use a brushless electric motor to intake air and then blow it out over an airfoil-shaped ramp.

Uses of Fans

Fans are used in a variety of applications, including ventilation, cooling, particulate removal, and drying. They are also used in heating and air conditioning systems to circulate air.

See Also

• HVAC
• Wind tunnel
• Dyson