A vacuum cleaner is a device that uses an air pump to create a partial vacuum to suck up dust and dirt, usually from floors. Most homes with carpeted floors in developed countries possess a vacuum cleaner for cleaning. The dirt is collected by a filtering system or a cyclone for later disposal. Booth started the British Vacuum Cleaner Company and refined his invention over the next several decades. Though his "Goblin" model lost out to competition from Hoover in the household vacuum market, his company successfully turned its focus to the industrial market, building ever-larger models for factories and warehouses. Booth's company lives on today as a unit of pneumatic tube system maker Quirepace Ltd.
Hoover is also notable for an unusual vacuum cleaner, the Hoover Constellation, which is a canister type but lacks wheels. Instead, the vacuum cleaner floats on its exhaust, operating as a hovercraft, although this is not true of the earliest models. They had a swivel top hose with the intention being that the user would place the unit in the center of the room, and work around the cleaner. Introduced in 1952, they are collectible, and are easily identified by the spherical shape of the canister. They tended to be loud, had poor cleaning power, and could not float over carpets. But they remain an interesting machine; restored, they work well in homes with lots of hardwood floors.
Vacuum cleaners working on the cyclone principle became popular in the 1990s, although some companies (notably Filter Queen and Regina) have been making vacuum cleaners with cyclonic action since 1928. In 1959 Amway patented the first 'bagless' cyclonic vacuum, called the CMS 1000. Modern cyclonic cleaners were adapted from industrial cyclonic separators by British designer James Dyson in 1985. He launched his cyclone cleaner first in Japan in the 1980s at a cost of about US$1,800 and later the Dyson DC01 upright in the UK in 1993 for £200. It was expected that people would not buy a vacuum cleaner at twice the price of a normal cleaner, but it later became the most popular cleaner in the UK.
Cyclonic cleaners do not use bags: instead, the dust collects in a detachable, cylindrical collection vessel. Air and dust are blown at high speed into the collection vessel at a direction tangential to the vessel wall, creating a vortex. The dust particles and other debris move to the outside of the vessel by centrifugal force, where they fall because of gravity, and clean air from the center of the vortex is expelled from the machine after passing through a number of successively finer filters at the top of the container. The first filter is intended to trap particles which could damage the subsequent filters that remove fine dust particles. The filters must regularly be cleaned or replaced to ensure that the machine continues to perform efficiently. Since Dyson, several other companies have introduced cyclone models, including Hoover, and the cheapest models are no more expensive than a conventional cleaner.
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