# Bladeless fans launched !

#### pixel01

Here is the news:
Who can explain to me what is behind the fan?

Thanks

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#### mgb_phys

Homework Helper
The fan is in the base - it pushes air through the circumference of the ring where it comes out along the axis through tiny holes.
The idea is a smoother airflow and no whirling blades - so quieter and safer

#### pantaz

There's a write-up on Wired:

"The unit is essentially one of Dyson’s vacuum cleaners working in reverse. The gray base station sucks up air and forces it through the circular blue thing that sits atop the rig. When the air jets through the front of the circle, it creates a suction behind and to the sides that draws more air through the loop and makes the fan more powerful. Dyson claims the Multiplier increases pressure 15-fold and spews 118 gallons of air every minute."

"The Air Multiplier will go on sale on this fall and will cost $300 -$330."

#### FredGarvin

That is an insane amount for an air inducer with iPod styling. This is one item I will wait for the Chinese to get a hold of and reverse engineer for 1/10th the price. I give Dyson credit for his vacuum, but he is losing touch with reality.

#### Topher925

So the thing isn't really blade-less is it? Its just that the fan itself is housed in the base. Wouldn't a regular fan be a lot more efficient (along with cheaper) than one of these iFans?

#### pixel01

So the thing isn't really blade-less is it? Its just that the fan itself is housed in the base. Wouldn't a regular fan be a lot more efficient (along with cheaper) than one of these iFans?
The inventer just wants to have a smoother fan for the first reason.

#### FredGarvin

I know. I can't think of how many times I have sat in front of a fan and said "Gee...I wish the flow from my fan was smoother."

The only things he's got going are possible energy savings and safety.

#### seb7

I'm assuming that the moving air lowers the pressure in the centre thus dragging in more air to move with it.

Looking at this, I'm wondering, can the same principle be applied to an electric current. Could a small DC electrical current be applied in such a way as to creates a current flow 15 times more greater?

#### mgb_phys

Homework Helper
Not quite.
It drags more through the hole at low speed by having a very high speed airflow at the edges - you don't gain any extra airflow. In fact it's less efficenct because of the energy lost as the high pressure air expands out of the small holes.

In electrical terms it's like short circuiting something - you get a lot more current flowing at a reduced voltage. But you don't get something for nothing

#### DaveC426913

Gold Member
OK, technically the "bladeless" claim is false, but functionally (i.e. as a user uses it), it is true. I think that is a valid claim, since he's selling a product, not an engineering design. All the user-focused things relevant in a bladed fan do not exist in this device. And that's what's important.

Tell me, would anyone likewise cry foul at the claim that a hovercraft is a wheelless vehicle? I could probably find hundreds of wheels in a hovercraft, yet...

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#### Blenton

Still, what a conversational piece to have.

#### minger

OK, technically the "bladeless" claim is false, but functionally (i.e. as a user uses it), it is true. I think that is a valid claim, since he's selling a product, not an engineering design. All the user-focused things relevant in a bladed fan do not exist in this device. And that's what's important.

Tell me, would anyone likewise cry foul at the claim that a hovercraft is a wheelless vehicle? I could probably find hundreds of wheels in a hovercraft, yet...
I don't really think you're talking apples and apples here. Sure, in a hovercraft, there may be wheels that support secondary systems and such; the wheels aren't integral to the concept and idea of a hovercraft.

When I think of a fan, or even an "air moving device" that has claims of "bladeless", then I sure as hell don't expect circular ducting sitting on top of a normal desk fan.

#### mgb_phys

Homework Helper
Well zero emission vehicles have emissions - they are just hidden somewhere else that you cant see them. Same principle really.

#### DaveC426913

Gold Member
I don't really think you're talking apples and apples here. Sure, in a hovercraft, there may be wheels that support secondary systems and such; the wheels aren't integral to the concept and idea of a hovercraft.

When I think of a fan, or even an "air moving device" that has claims of "bladeless", then I sure as hell don't expect circular ducting sitting on top of a normal desk fan.
My point is that, as a product, it is a bladeless fan.

It does not operate like a bladed fan; it does not have the dangers or annoyances of a bladed fan. (Also, I'll bet dollars to donuts it is not a normal desk fan in the base.)

He's selling a product, not trying to wow physics buffs with some alleged new technology.

#### minger

I'm not trying to argue for the sake or arguing, but I guess this does bring a decent conversation in claims. At what point does it go from bladeless to blades then?

Right now a fan drives flow through a perforated torus (essentially), and we call it bladeless.

If the torus becomes simply a torodial opening, is it still bladeless? What if the opening becomes circular, essentially making it a ducted fan, is it still bladeless? What if the ducting shortens to just a protective shroud over the blade?

To me, it's analagous to saying that things like biodiesel and hydrogen are clean energy, when it requires an abundance of "dirty" energy to make them.

#### FredGarvin

I think I'll still stick with the "rip off" label myself.

#### DaveC426913

Gold Member
I think I'll still stick with the "rip off" label myself.
What is it being ripped off of?

#### FredGarvin

What is it being ripped off of?
I mean a rip off in terms of $300 for a cheap fan. #### DaveC426913 Gold Member I mean a rip off in terms of$300 for a cheap fan.
How do you know it's cheap?

#### FredGarvin

How do you know it's cheap?
Please. It's a DC brushless motor in a plastic housing with a plastic hoop on the top.

#### russ_watters

Mentor
My point is that, as a product, it is a bladeless fan.

It does not operate like a bladed fan; it does not have the dangers or annoyances of a bladed fan. (Also, I'll bet dollars to donuts it is not a normal desk fan in the base.)

He's selling a product, not trying to wow physics buffs with some alleged new technology.

#### FredGarvin

I own a Dyson vacuum and I give them credit for that. It's the best vacuum (and the most expensive) I have ever owned.

I did have to laugh at the GPM performance. I gave them benefit of doubt in that how many people know what an SCFM is? Heck, I know engineers that have a tough time with that.

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