I just did read an add for a "bladeless fan", a so called air-multiplier 
made by Dyson.

When I read the add I clicked on to find out more. Dyson would surely not 
lie to us - so I was really interested in how they build a wonder like this.

Any electric fan, easy to clean, no blades? How is it done? Electromagnetic 
fields? I simply had to see...

Now take a look at this thing and tell me - should I ROTFL or start to weep 
for the poor fools who buy this?

http://www.dyson.com/technology/airmultiplier.asp

Besides: do US laws allow for blatant lies in ads? Bladeless - my ass! And 
easy to clean? I doubt you can clean the real fan-parts at all.

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TC wrote:

> Now take a look at this thing and tell me - should I ROTFL or start to weep 
> for the poor fools who buy this?
> 
> http://www.dyson.com/technology/airmultiplier.asp
> 
> Besides: do US laws allow for blatant lies in ads? Bladeless - my ass! And 
> easy to clean? I doubt you can clean the real fan-parts at all. 

What makes you think it's a lie?

http://en.wikipedia.org/wiki/Air_Multiplier#Dyson_Air_Multiplier

It doesn't have blades; it uses an impeller. And although I can't recall 
the name for it now, I've seen a device similar to this that passively 
accelerates airflow.

They had a rocket motor blow into a bag, and it did inflate, but quite 
slowly. Then they added this compression ring, and when the rocket motor 
starts blowing, the ring causes air from the surroundings to be sucked 
in as well, causing the bag to fill much more rapidly.

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"TC" <do-not-reply@i-do get-enough-spam-already-2498.com> wrote:
> I just did read an add for a "bladeless fan", a so called air-multiplier
> made by Dyson.
>

Put my hand through one in the store.

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> It doesn't have blades; it uses an impeller. And although I can't recall 
> the name for it now, I've seen a device similar to this that passively 
> accelerates airflow.

I don't have much doubt that the shape of the ring actually amplifies 
airflow. And airflow is probably not as chopped up.

However, I think that there is small functional difference between a 
fan-blade and what is used in the impeller. It all boils down to rotating 
structures pusing air molecules forward. I expected something >new<.

And I really doubt that cleaning the impeller is easier than cleaning a fan.

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> Put my hand through one in the store.

Sure - but the impeller (hidden in the base) is still based on rotating 
mechanical objects. Or am I wrong here? Did I miss something? If so - my 
apologies.

I see small difference (in priciple) between it and a fan. Nothing really 
new, apart from the ring-geometry used to amplify airflow.

And I really doubt that the impeller is more easy to clean than a 
conventional fan. What if enough dust is sucked inside the impeller? >Can< 
you even clean it?

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TC wrote:

> However, I think that there is small functional difference between a 
> fan-blade and what is used in the impeller. It all boils down to rotating 
> structures pusing air molecules forward. I expected something >new<.

A fan pushes air forwards by using flat blades to fan it. An impeller 
pushes air *outwards* by centrifugal force. That's an entirely different 
mode of action. (Although of course impellers aren't exactly new either.)

What _is_ new is that by using clever air currents, you can make the 
draft much bigger with less effort. And I guess it looks kinda neato.

> And I really doubt that cleaning the impeller is easier than cleaning a fan. 

 From what little I've seen, fans tend to get dusty when they're not in 
use, because they're exposed to the air. An impeller, by definition, is 
internal. When it's not running, there's very little air to get it dusty.

Still, at the end of the day, if you don't like it, don't buy one. :-)

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On 6/4/2010 8:26 AM, Invisible wrote:
> TC wrote:
>
>> However, I think that there is small functional difference between a
>> fan-blade and what is used in the impeller. It all boils down to
>> rotating structures pusing air molecules forward. I expected something
>> >new<.
>
> A fan pushes air forwards by using flat blades to fan it. An impeller
> pushes air *outwards* by centrifugal force. That's an entirely different
> mode of action. (Although of course impellers aren't exactly new either.)
>
> What _is_ new is that by using clever air currents, you can make the
> draft much bigger with less effort. And I guess it looks kinda neato.
>
>> And I really doubt that cleaning the impeller is easier than cleaning
>> a fan.
>
>  From what little I've seen, fans tend to get dusty when they're not in
> use, because they're exposed to the air. An impeller, by definition, is
> internal. When it's not running, there's very little air to get it dusty.
>
> Still, at the end of the day, if you don't like it, don't buy one. :-)


The reverse sides of the fan blades get dusty too, even when the fan is 
in use.

-- 
http://isometricland.com

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Don't know about how you'd clean the fan I saw, if anything it's a greater
mildew risk for the mechanics trapped inside.

But the device was bladeless in the sense that I couldn't imagine a 3 year old
hurting himself with it unless they bit on the power cord.



"TC" <do-not-reply@i-do get-enough-spam-already-2498.com> wrote:
> > It doesn't have blades; it uses an impeller. And although I can't recall
> > the name for it now, I've seen a device similar to this that passively
> > accelerates airflow.
>
> I don't have much doubt that the shape of the ring actually amplifies
> airflow. And airflow is probably not as chopped up.
>
> However, I think that there is small functional difference between a
> fan-blade and what is used in the impeller. It all boils down to rotating
> structures pusing air molecules forward. I expected something >new<.
>
> And I really doubt that cleaning the impeller is easier than cleaning a fan.

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Invisible wrote:
> It doesn't have blades; it uses an impeller.

http://en.wikipedia.org/wiki/File:Pump_Impellers-1.jpg


Looks like blades to me.  I'm not really sure what the difference between 
"blades" and "impeller" is, tho.

-- 
Darren New, San Diego CA, USA (PST)
    Eiffel - The language that lets you specify exactly
    that the code does what you think it does, even if
    it doesn't do what you wanted.

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On 2010-06-04 08:17, TC wrote:
> I see small difference (in priciple) between it and a fan. Nothing really
> new, apart from the ring-geometry used to amplify airflow.

There is nothing new, only modifications and improvements upon existing 
things and concepts.

--
Tim Cook
http://empyrean.freesitespace.net

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