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A "bladeless" fan blows air from a ring with no external blades. Its blades are hidden in its base. It was invented by a Japanese company in 1981. Dyson claims that its bladeless fans (U.S. Patent 8,454,322) produce a more constant airflow than traditional fans.
The air is drawn in by a fan in the base and then directed up into a ring. It comes out of a crack all around the ring and passes over a shape like that of an aircraft wing. Industrial designer Sir James Dyson named his fan the Air Multiplier.
Dyson sued Chinese companies because they began selling bladeless fans for much less than Dyson. The Chinese responded that Dyson can not patent an invention that has already been invented, that Toshiba invented the fan in 1981 and its patent expired after 20 years.