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Thread: Is there a future for fan blades?

  1. #9
    More than 30 posts! Scrutineer
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    Default Re: Is there a future for fan blades?

    This technology has been around for years, anyone in the agricultural / farming business uses them all the tine for moving grain along long pipes. Small compressor supplies air to an anulus just inside the belmouth.

    I had a 75mm dia one to play with about 15years ago but you do need quite high pressure air > 100psi to really create a good airflow


    Keith

  2. #10
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    Default Re: Is there a future for fan blades?

    I've also seen this before (quite a few years ago) in a barn where compressed air was used to move grain along a pipe. I recall it being rather noisy and a *lot* of compressed air to make it work. I suspect the fan in the base of Dyson's 'new' invention is making quite a racket and using a fair bit of power (if it's really moving as much air as they claim it is). In addition, there appear to be quite a few inefficient bends and turns the air has to make from the fan to the annular exit.

    Bob

  3. #11
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    Default Re: Is there a future for fan blades?

    I agree with all of you, BUT, it looks FUNKY, so it will sell I am sure of it.
    In the beginning there was the Cube; I know where is came from and it has the power to create Hover life. But with great power comes great Fun.

  4. #12
    Forum God > 400 posts Club Member Jon Pert's Avatar
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    Default Re: Is there a future for fan blades?

    Quote Originally Posted by Keith Oakley View Post
    'Chunky air' = air turbulence= noise. So at first glance this should be quieter, but the Dyson website makes no claims as to noise. Is it because the high pressure fan in the base isn't quiet?
    Is the website suggesting the fan in the base is shifting 27 litres/min then because of the 15X amplifier effect the whole thing is shifting 400 litres/min?
    So why isn't this applicable to a hovercraft thrust 'fan'?
    Keith
    Make your own mind up on the noise front! Video here. http://www.telegraph.co.uk/technolog...eless-fan.html
    Cheers

    SixpackPert



    "Computer games don't affect kids. If Pacman would have affected us as children, we would now run around in darkened rooms, munching pills and listening to repetitive music"

  5. #13
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    Default Re: Is there a future for fan blades?

    Well it certainly sounded noisy to me! I couldn't hear a thing when they turned on the conventional fan and they also remarked that the Dyson was set at its lowest setting!

    Bob

  6. #14
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    Default Re: Is there a future for fan blades?

    They also confirmed that both fans had the same 40watt power consumption. I can't believe the Dyson shifts 15 times more air for that 40watts - it would be too strong in the office!
    Keith

  7. #15
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    Default Re: Is there a future for fan blades?

    It's just marketing spiel Keith. It uses 1/15th of the volume of air to move the remainder - it is no more efficient (and may even be less efficient) than a conventional axial fan (they wouldn't have missed the chance to say so if it was more efficient ).

    It's still a cool looking device!

  8. #16
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    Default Re: Is there a future for fan blades?

    Quote Originally Posted by Keith Oakley View Post
    They also confirmed that both fans had the same 40watt power consumption. I can't believe the Dyson shifts 15 times more air for that 40watts - it would be too strong in the office!
    Keith
    It can't be more efficient. The air coming from the annular ring is at high velocity, and the power is proportional to V^2. On top of this, there will be significant losses as the high velocity air entrains the low velocity air - its a submerged jet, just a funny shape, like the submerged jet at the heart of the servovalves we make. It's not an efficient system...

    Ian
    Ian Brooks
    Gloucester, UK
    http://www.hoverclub.org.uk

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