Earlier bagless vacuums, including Dyson's, deposit most of the collected dust into the drum - but the really fine particles remain in the airstream until they are caught in the exhaust filter or filters.
As those filters collect dust the airflow becomes obstructed and the suction decreases, much as happens when an old-school vacuum bag becomes full. Cleaning a filter is a messier and more unpleasant job than just emptying a bagless vacuum's canister.
How did Dyson manage to dump the dust filter? Senior design engineer Martin Peek told iTWire that the project took six years from the original brief.
The solution was to fit a flexible tip to the nozzle. The tip then oscillates in the spinning airflow, and that movement keeps it clear.
But the degree of flexibility had to be exactly right. Too stiff, and blockages still occurred. Too flexible, and the nozzle collapses like a blocked drinking straw.
Getting the tips right took around three years, but it was worth it: the final design - dubbed 'Cinetic' (pronounced 'kinetic') - was tested to the equivalent of 10 years of domestic use and showed no loss of suction.
"It's an amazing achievement - you buy it, you use it; that's it," said Mr Peek.
Please read on for more on the DC54's performance, and news of Dyson's latest cordless vacuum.
The IEC standard for testing vacuums requires less than one canister-full of dust to be collected, which is not enough to affect the filters in older designs, so they can get away with 'no loss of suction' claims that aren't matched in real-life use, he explained.
That IEC standard calls for a specific type of replica dust containing particles and fibres of particular sizes. "We ran the supplier dry" during testing, Mr Peek said. In the last two years, Dyson used over two tonnes of dust, which is supplied in 3kg tins.
The exhaust air is free of particles down to 0.5 micron, which means mould spores and pollen are collected in the canister.
Mr Peek claimed that in some cities the Cinetic's exhaust stream is cleaner than the ambient air.
Dyson has also introduced the Digital Slim DC59 cordless vacuum featuring a redesigned motor and a two-stage multi-cyclone design that provides three times the suction of any other cordless vacuum product, he claimed.
Company officials said the DC59 provides the same performance as a mains-powered vacuum.
A new nickel/manganese/cobalt battery provides greater power density, allowing 20 minutes use per charge, and this battery/motor combination is said to deliver practically constant suction until the battery is exhausted.
The DC59 comes in two variants, the $649 Animal model and the $599 Multi-floor version.