Publish Time: 2023-06-02 Origin: Site
A fan is a powered machine used to create airflow.A fan consists of a rotating arrangement of blades or vanes, usually made of wood, plastic, or metal, that act on the air.The rotating assembly of blades and hub is called the impeller, rotor or runner.Usually, it's contained in some form of casing or casing.This can direct airflow, or improve safety by preventing objects from touching the fan blades.Most fans are powered by electric motors, but other power sources are also available, including hydraulic motors, hand cranks, and internal combustion engines.Mechanically, a fan can be any rotating blade or blade used to create an airflow.Fans produce airflow at high volume and low pressure (albeit above ambient pressure), as opposed to compressors producing high pressure at relatively low volume.Fan blades typically rotate when exposed to air-fluid flow, and devices that take advantage of this, such as anemometers and wind turbines, often have a fan-like design.Typical applications include climate control and personal thermal comfort (e.g., powered desks or pedestal fans), vehicle engine cooling systems (e.g., in front of radiators), mechanical cooling systems (e.g., inside computers and audio power amplifiers), ventilation, smoke extraction , winnowing (e.g., separating chaff from chaff), dusting (e.g., suction in a vacuum cleaner), drying (often in conjunction with a heat source), and providing ventilation for fires.In the case of industrial heat exchangers, some fans may be used indirectly for cooling.
While fans are effective at cooling people, they don't cool the air but rather work through evaporative cooling of sweat and increased convection of heat into the surrounding air due to the fan's airflow.Therefore, if the surrounding air temperature is close to body temperature and the humidity is high, the fan may be less effective in cooling the body.
Steam
In 1849, William Brunton's 6m radius steam-driven fan was commissioned at the Gelly Gaer coal mine in South Wales.The model was exhibited at the Great Exhibition of 1851. Also in 1851, Scottish physician David Boswell Reid installed four steam-powered fans in the ceiling of Liverpool's St George's Hospital so that the pressure generated by the fans forced incoming air up and through Vents in the ceiling.The technique was improved by James Nasmyth, Frenchmen Theophile Guibal and J. R. Waddle.
Electric
In 1882, developed the world's first electric ceiling fan.During this period of intense innovation, fans powered by alcohol, petroleum, or kerosene were common in the early 20th century.In 1909, Japan's KDK took the lead in inventing mass-produced household electric fans.In the 1920s, industrial advancements allowed steel fans to be mass-produced in different shapes, which lowered the price of fans and made them more affordable for more homeowners.In the 1930s, the first Art Deco fan ("Silver Swan") was designed by Emerson.By the 1940s, Crompton Greaves of India was the world's largest manufacturer of electric ceiling fans, selling primarily in India, Asia, and the Middle East. By the 1950s, table and standing fans were brightly colored.Window and central air conditioning in the 1960s led many companies to stop producing fans but in the mid-1970s, as people became more aware of the cost of electricity and the amount of energy used to heat and cool their homes, a switch was made to- Century-style ceiling fans gain popularity again as decorative and energy-saving fixtures.In 1998, William Fairbank and Walter K.Boyd invented the High Volume Low Velocity (HVLS) ceiling fan, which was designed to reduce energy consumption by moving relatively large volumes of air through long fan blades spinning at low speeds.