But that's been the idea well all along. Modern central vacuum systems I knew of as early as the 1960s were bagless and used cyclonics, though possibly not referred to as that, for dust collection. The idea was that the central vacuum could be used without bags -- a selling point -- and required infrequent emptying. This meant a large dust container. The estimation for emptyiing was usually given as two time or so per year. If I recall correctly there was usually a conical baffle within the main unit that allowed incoming air to spin and shed most of the dirt it carried before being blasted outdoors.
Changes have been made in recent times because though the idea of a central vacuum system is appealing it may not be easily workable in some situations due feasibilty of exhaust placement. Thus came the central units we're seeing now that use large bags for dust collection plus exhaust filtration devices.
Please note that though Vacu-Flo produce a "filtered cylonic" system that does not require outside venting, saving on replacement bags, I wonder at the practicality considering the situation. You'd still have to do either filter clean-up or replacement to maintain the unit. Check out the links below especialy the PDF bearing the operators manual.
http://www.vacuflo.com/products_filteredcyclonic.html
http://www.vacuflo.com/pdf/FC300.pdf
Venson
This message was modified Feb 2, 2008 by Venson
Hey Dude, I really dont care about the Junk thats pushed in the U.K. , when the inventor going to reinvent a central vacuum with cyclonic suction?