Vacuum maker Dyson unveils its latest household device - a fan with no rotor

He is the man who brought us the vacuum cleaner without the bag.

Now Sir James Dyson has unveiled his latest household invention - the fan without the rotor.

Called the Dyson Air Multiplier, it is able to create a powerful, cooling breeze seemingly from thin air.

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Launching the product yesterday, Sir James explained that he got the idea while developing his Air Blade hand dryers, which force air though a tiny slit to 'brush' water from wet hands.

'We noticed that the hand dryer was drawing in a lot of air from its surroundings,' he said.

'So we started to think about how we might be able to put this effect to use.

We thought about creating an air moving device with no propeller or fan blade. Three years of development plus another year of testing later and this is the result.'

The Air Multiplier works by pushing air through a 1.3millimetre-wide slit that runs along its circumference.

As it is forced through the circle, the volume of travelling air increases by up to 15 times and its speed rises to 22mph.

Crucially, according to Sir James, the resulting air flow is smoother than that produced by normal fans.

He said: 'The amount of air it produces is up there with the very best of fans. We are not claiming that you get more air. But it's much better quality.

'Because there are no blades to "chop up" the air, it doesn't annoy you and it doesn't buffet you. But it cools you as it is a constant air stream.'

The machine comes in two sizes and a range of metallic colours. All models cost £199.

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Like most desk fans, it can oscillate through 90 degrees, but unlike other fans it has a dimmer-switch control.

And, of course, there are no rotor blades to get covered in dirt - or endanger the fingers of curious children.

The Air Multiplier, already available in specialist design shops and Harrods and Selfridges department stores, will be widely stocked across the country early next year.

Estimated to be worth around £500million, Sir James, 62, became one of Britain's best-known inventors after the success of his bagless vacuum cleaner in the 1990s.

Watch one excited user with their new Dyson fan...