"gregjohn" <pte### [at] yahoocom> schrieb im Newsbeitrag 
news:web.4c0917b8fc7ba212a00085090@news.povray.org...
> 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.

Granted. ;-)

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

To my untutored eye it is the same, shaped a bit differently, maybe.

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> 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.)

It is the reverse mode of action.

My computer's power-source has what I would call a fan. In fact, everybody I 
knows calls it this. Yet it impells air into the unit. So should it be named 
impeller?

> 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.

Yes. That's what caugt my eye. It does look good, and at first glance one 
wonders how it is done. Hence my disappointment when I found out. ;-)

> 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.

Look into your computer. If it is older than a year, examine the fans. Now, 
that is what I call dirty. The little impeller sucks in air. It will get as 
dirty, won't it?

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

Have you looked at the price? $329.99 - this is surely innovative. ;-)

http://www.dyson.com/store/fans.asp

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On 4/06/2010 8:14 PM, TC wrote:
> 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.
>
>
>

There are a couple of points that make it quite nice.

The air flow is created by a really neat impeller and high power 
electric motor.  I believe it was adapted from the Dyson 'airblade' hand 
dryer.  If you have not seen and used one of those you are in for a 
surprise!  Wow that thing is good.

In regard to dust being accumulated in the impeller, consider that it is 
a lot smaller than the blades of a conventional fan but generates a lot 
higher speed airflow.  Dust simply doesn't have a chance to build up on 
the working part.  How concerned are you about dust building up on the 
impeller of a turbo-charger in a car engine?

Then you might appreciate that the air that goes through the impeller is 
filtered.  This is used to entrain a larger air mass that doesn't pass 
through the impeller.  So whatever the final volume of air that is 
moved, less goes through the critical part of the Dyson than passes 
through the blades of a conventional fan - by more than an order of 
magnitude.

Dyson after all does know a bit about air flow and dust.

I guess that dust and fluff would build up on the leading edge of the 
annulus.  This would however be much easier to clean than on a 
conventional fan.  Just wipe it.  My current desk fan has a wire cage 
around the blade.  That collects dust and you have to remove the front 
part and take the blade out to properly clean it.

The other 'air multiplier' benefits are the quiet operation and steady 
airflow.

If they weren't so expensive I'd get one.  Still will if I see one on 
sale.  I do have a Dyson vacuum cleaner and it is so much better than 
any other type I have used.  A great alternative concept to how the 
whole thing should be done, brilliant design, brilliantly engineered 
with quality materials.  Absolutely the best and not one fault with it 
that I can see.

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this is it!  I name it the "WTF thread of the day" of yesterday.

And it is a fan and will get dirty, except you quite likely won't be able to
clean it except by getting it to maintenance.  Lesson to be learned here:
underneath all shiny and neato things there's always a lot of dirt. :P

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On 5/06/2010 3:39 PM, nemesis wrote:
> this is it!  I name it the "WTF thread of the day" of yesterday.
>
> And it is a fan and will get dirty, except you quite likely won't be able to
> clean it except by getting it to maintenance.  Lesson to be learned here:
> underneath all shiny and neato things there's always a lot of dirt. :P
>
>

I take that 'WTF' as disagreeing with me.

Your only point that seems specific is that fans get dirty and you imply 
that this will be a problem that can only be fixed by maintenance? 
Correct me if that isn't what you were saying.

So lets see.  I have a Dyson vacuum cleaner.  It is used pretty much 
once a week to clean a 4 bedroom house with carpets everywhere except 
the wet floor areas.  I've had it for about 6.5 years.

By its nature there is a large amount of dusty and dirty air being 
passed through the device.  Number of trips to maintenance thus far is 
zero.  Apparent loss of functionality due to the inevitable (you say) 
buildup of dirt is zero.

We bought it on the recommendation of commercial carpet cleaners who use 
uprated models of the same thing.  I specifically asked about 
reliability and they said they had never had a problem and never had to 
do any maintenance on them.  That was based on heavy duty use and many 
units in the same company.

A traditional fan has large slow moving blades that all of the air that 
they move passes through.  Around that they have a wire cage covering 
both the in and out sides.  They are pretty good at collecting dust and 
fluff.  Very poor at shedding it.  In fact the dust that they collect 
seems to help collect more.

You shouldn't generalise from there to all fans in all devices. 
Especially when they are substantially different and designed by people 
who specialise in the field.

Now I can't say that the Dyson fan is equally as good as the model of 
Dyson vacuum cleaner that we have.  Seems like there isn't the same sort 
of problem to justify such an expensive solution.  I haven't tried one 
to see if it is indeed quieter or better in any way.

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>> 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.)
> 
> It is the reverse mode of action.
> 
> My computer's power-source has what I would call a fan. In fact, everybody I 
> knows calls it this. Yet it impells air into the unit. So should it be named 
> impeller?

A fan works by having blades with a uniform cross-section, but angled to 
accelerate air parallel to the plane of rotation. If you spin the blades 
one way, it blows forwards. If you spin them the other way, it blows 
backwards.

An impeller uses centrifugal forces to blow air *outwards* (i.e., away 
from the center of rotation - usually meaning that air is sucked into 
the impeller through a port near the center and exits the impeller from 
the edges). If you spin the impeller the other way, the air still flows 
in the same direction.

>> 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.
> 
> Yes. That's what caugt my eye. It does look good, and at first glance one 
> wonders how it is done. Hence my disappointment when I found out. ;-)

I can understand that. ;-)

>> 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.
> 
> Look into your computer. If it is older than a year, examine the fans. Now, 
> that is what I call dirty.

True. Then again, the entire inside of my PC is carpeted in dust; why 
not the fans? I guess somebody more qualified than me can explain why 
fans get dusty...

>> Still, at the end of the day, if you don't like it, don't buy one. :-)
> 
> Have you looked at the price? $329.99 - this is surely innovative. ;-)

Ouch! o_O

OK, definitely don't buy one...

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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Paul Fuller wrote:

> The air flow is created by a really neat impeller and high power 
> electric motor.  I believe it was adapted from the Dyson 'airblade' hand 
> dryer.  If you have not seen and used one of those you are in for a 
> surprise!  Wow that thing is good.

We have a Dyson Airblade at work. It is THE most useless thing I've ever 
encountered!

When I was a child, it never ceased to amaze me that hand driers 
actually work. I mean, sure, it blows hot air on your hands. The 
principle makes sense. But surely you're going to have to wait a hell of 
a long time before your hands become *dry*, right?

But no, without fail it always manages to dry your hands in seconds. I 
mean, *really* dry!

...and then we come to the Dyson Airblade. Now I don't know if this 
particular one is just faulty (wouldn't surprise me; everything else in 
this building is!), but it is *hopeless*. The air it blows at you is 
utterly freezing on your wet hands. It blows so hard that you can 
actually see it flobbling your flesh around. And it's deafeningly loud.

I'm not even kidding. I took a sound meter in there and measured the 
sound level. The reading came back as 98 dB (A-weighted) or 93 dB 
(C-weighted). Apparently that's in the range that's supposed to cause 
temporary hearing damage.

And, quite apart from making your hands extremely cold and mashing your 
skin around quite unconforably, IT DOESN'T DRY YOUR HANDS! Which, given 
that this is the entire purpose for which the device exists, qualifies 
it as an unmitigated failure IMHO.

> Dyson after all does know a bit about air flow and dust.

What they definitely know how to do is design products that look 
"innovative" and "sciency". Fair play; I couldn't do that.

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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On 5/06/2010 6:07 PM, Orchid XP v8 wrote:
>
> We have a Dyson Airblade at work. It is THE most useless thing I've ever
> encountered!
>

Strange how our experience can be so different.  I was surprised how 
fast it was and would say it was the best I've used.  No wait to heat 
up.  No failure to register that my hands were in position.  Done in 
about 10 seconds.  Didn't notice that it was loud although it may well 
have been.

>
> What they definitely know how to do is design products that look
> "innovative" and "sciency". Fair play; I couldn't do that.
>

Yes they do that.  He should be designing spacecraft for SF book covers 
and movies.  Still I find (based on the vac) that it is very well made 
and works extremely well.

I understand that some of the original patents protecting the Dyson 
vacuum cleaner have expired.  Now there are lots of cheap knock offs on 
the market that emulate the 'bagless' aspect.  The couple I've seen up 
close looked cheap and frail plus lacked a lot of the nice secondary 
features.

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On 05/06/2010 9:07 AM, Orchid XP v8 wrote:
> We have a Dyson Airblade at work. It is THE most useless thing I've ever
> encountered!



hands still wet. On the other hand <groan> the air blades are warm and 


-- 

Best Regards,
	Stephen

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