Dyson was the brand that first introduced bladeless fans to the world. As one of TechRadar’s Homes editors, I regularly find myself writing about the best fans on the market, but I’ll be honest – I’ve never quite understood how these machines actually work. Where is that blast of air coming from?
On a recent visit to Dyson’s campus in Malmesbury in the west of England, I got the chance to pick the brains of Sophie Harold, an acoustics and vibration engineer at Dyson. Here’s what I learned…
The terms that Dyson employees use to refer to the brand’s bladeless fans are ‘Loops’, ‘Amps’ (short for ‘Air amplifiers’), or, occasionally, ‘Race tracks’. This is the traditional Dyson aircare product format.
“They’ve got a gap in the middle [and] slots on the side, and they’ve got fast air out of the plastic outer loop,” says Sophie. This, she explains, causes something called ‘entrainment’, where the loop pulls in air from elsewhere in the room, to create an effect the brand calls ‘air multiplication’.
“It means that… say you put the new CF1 on the desk, the air that you feel at your face is even more air than the motor or the compressor itself is generating, because it’s dragging in air from the room as well,” Sophie continues.
Compact cones
The Loop is just one of the formats Dyson uses to wrangle air. It also makes many of the best air purifiers on the market. In fact, a number of its models act as fan-purifier combos, because the processes required are so similar.
Some of Dyson’s more recent purifiers use a ‘Cone’ rather than a Loop. This looks a bit like a bowl, and appears on the likes of the Dyson Big+Quiet. Because there’s no need for an empty space in the middle, these kinds of products can be a bit more compact in shape, and shorter. Or, they can cram an awful lot of power without being absolutely massive – as is the case with the Big+Quiet.
“They use Coanda, so that’s causing [air]flow to adhere to a surface. That’s the same tech that the Airwrap barrels use to cause the hair to swirl around and get that nice curl shape,” says Sophie.
“What it does here is it uses the surface to direct the air so where you would have to oscillate a Loop fan, with a Cone, you can just vary the strength of the jet at the top and the bottom, and it moves the flow up and down. That’s the primary thing that that shape can do.”
Starry eyed
The newest air purifier in the Dyson lineup – the HushJet Purifier Compact – doesn’t use a Loop or a Cone, it uses a ‘Star’ nozzle.
The new Star nozzle is interesting because it causes entrainment without having to have the big gap in the center (as Loops do), so it can have a more compact shape than an amp fan. The HushJet is Dyson’s first compact air purifier.
“It drags air from the rest of the room with it, making a really powerful jet, and it does that by having that star shape,” says Sophie. “By having the kind of bending edges, it’s still encouraging air from the surrounding region to join in with the fast jet.”
“It also means the air is quite fast,” she continues. “Similar to the Air amps, which have very narrow slots, this has a contraction into the star shape, smaller than the motor is, which means the air can go really quickly, mix well and purify the room.” I’ve heard it likened to a jet engine, or perhaps more relatably, the Concentrator nozzle on a hair dryer.
Fans and filters
As I said earlier, many of Dyson’s fans can also function as air purifiers. However, not all models are pulling double duty. I asked Sophie how the designers’ approach differs depending on what the appliance needs to do.
“[For a] purifier, you might focus on mixing the air in the room, rather than directing the air flow at your face. It’s much more important to get good filters on the product,” she explains.
“Whereas things like the CF1 [fan], they don’t have filters on, and that’s because it means you can run the motor more efficiently, get lower running costs, and just get the cool flow on your face, rather than focusing on really getting all the air through and purified.”
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