From WikiPedia:

http://en.wikipedia.org/wiki/Vacuum_cleaner

“Recent developments about Vacuum cleaner

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 model is no more expensive than a conventional cleaner.”

所以，在这里，渦卷式-- Cyclonic vacuum cleaners ； 免紙袋 -- without paper bag。在国内， 很多厂商翻译成“旋风式吸尘器”，比如， http://apply.cpst.net.cn/news/flash/1027477872.shtml
http://ivproe.com/viewarticle.php?id=23182

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Note added at 3 hrs (2006-07-18 14:16:13 GMT)
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Cyclonic vacuum cleaners without paper bags. 写少了个S。