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Fan (machine)

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A fan is a powered machine designed to create airflow.

Hatari 18 inch fan
Hatari 18 inch fan

It functions by using rotating vanes, or blades, to act upon the air. These blades are typically constructed from materials like wood, plastic, or metal. The central assembly of these blades and the hub is called an impeller, a rotor, or a runner. Most fans are enclosed within a housing or a case. This structure directs the airflow and provides safety by preventing objects from touching the blades.

Patent, Mechanical Fan, 1830
Patent, Mechanical Fan, 1830

Mechanically, a fan moves a high volume of air at a low pressure. This process differs from a compressor, which moves a low volume of air at a high pressure. Most modern fans are powered by electric motors. However, other power sources can be used, such as hydraulic motors, handcranks, or internal combustion engines. The movement of air is a two-way street in physics. While fans push air, a moving air-fluid stream can also cause a blade to rotate. This principle is why devices like wind turbines and anemometers share similar designs with fans.

There are three main mechanical types of fans used for moving air: axial, centrifugal, and cross-flow. Axial-flow fans feature blades that force air to move parallel to the shaft of rotation. These are used in everything from small computer cooling fans to massive industrial cooling towers. Standard axial fans often have diameters between 300 and 400 mm, or much larger at 1,800 to 2,000 mm. They can operate under pressures up to 800 Pa.

Luefter y.s.tech pd1270153b-2f
Luefter y.s.tech pd1270153b-2f

Other types, like centrifugal or radial fans, move air in different patterns to suit specific industrial needs.

Fans have a long and diverse history. In ancient Egypt and India, people used handheld fans made from plant fibers or bamboo strips. Around 180 CE, a Chinese engineer named Ding Huan created a manual rotary fan. This device featured seven wheels and measured 3 meters in diameter. During the Tang dynasty, the Chinese used hydraulic power to rotate these wheels for air conditioning. By the 17th century, scientists like Robert Boyle and Robert Hooke established the principles of airflow and vacuums. In 1727, John Theophilus Desaguliers demonstrated using fans to remove stagnant air from coal mines. This was vital to prevent asphyxiation among miners.

Patent, Mechanical Fan, 1830
Patent, Mechanical Fan, 1830

The industrial era brought massive steam-powered machines. In 1849, William Brunton designed a steam-driven fan with a 6-meter radius. This machine was exhibited at the Great Exhibition of 1851. Later, in 1851, Dr. David Boswell Reid installed four steam-powered fans in a Liverpool hospital. These fans used pressure to force incoming air upward through ceiling vents. The transition to electricity changed everything for the average person. Schuyler Wheeler invented the electric fan between 1882 and 1886. Philip Diehl developed the first electric ceiling-mounted fan in 1882.

Elektrische ventilator van het merk Calor - INDUS V09832
Elektrische ventilator van het merk Calor - INDUS V09832

Today, fans serve many specialized roles. They are used for climate control, personal comfort, and vehicle engine cooling. In computers, they prevent hardware from overheating by exhausting hot air. They are also used in winnowing to separate chaff from grain, or in vacuum cleaners to remove dust. Interestingly, fans do not actually lower the temperature of the air. Instead, they provide cooling through evaporative cooling of sweat. The airflow increases heat convection away from the body. However, fans become less effective if the air is very humid or near body temperature.

Modern innovations continue to improve efficiency. In 1998, William Fairbank and Walter K. Boyd invented the high-volume low-speed (HVLS) ceiling fan. These fans use very long blades that rotate slowly to move massive amounts of air while using less energy.

Ceiling fan with lamp
Ceiling fan with lamp

This makes them excellent for large spaces. From ancient handheld bamboo strips to high-tech industrial systems, fans remain essential for managing heat and air in our world.

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🖼️ Images & Media (9)
File:Hatari 18 inch fan.jpg
Hatari 18 inch fan.jpg
File:Patent, Mechanical Fan, 1830.png
Patent, Mechanical Fan, 1830.png
File:Elektrische ventilator van het merk Calor - INDUS V09832.JPG
Elektrische ventilator van het merk Calor...
File:Ceiling fan with lamp.jpg
Ceiling fan with lamp.jpg
File:Luefter y.s.tech pd1270153b-2f.jpg
Luefter y.s.tech pd1270153b-2f.jpg
File:Cross-flow fan schematic patent.png
Cross-flow fan schematic patent.png
File:Tangential-flow-coloured-labels.png
Tangential-flow-coloured-labels.png
File:XinHui 新會碧桂園 Country Garden 大潤發 RT-Mart Fresh Food 01.JPG
XinHui 新會碧桂園 Country Garden 大潤發 RT-Mart...
File:UMA 2.JPG
UMA 2.JPG
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