[Gasification] tests to design a new cheap gasifier fan

Fri Nov 12 18:25:44 CST 2010

Jim, isn't eight inches a bit high? We use a lot of Cincinnati and Granger 
fans successfully and find their designs well presented and worth emulation 
and learning from their engineering, since we lack the time to rediscover 
wheels and sliced bread. (Thank you, Mark!)

Respectfully,

Bill Klein,
3i

----- Original Message ----- 
From: "jim mason" <jim at allpowerlabs.org>
To: "Discussion of biomass pyrolysis and gasification" 
<gasification at lists.bioenergylists.org>
Sent: Friday, November 12, 2010 5:13 PM
Subject: Re: [Gasification] tests to design a new cheap gasifier fan

here's some update on the fan tests, including a picture of many
rotors tested: http://gekgasifier.com/forums/showthread.php?p=1664#post1664

the suggestions from all of you were very intersting.  especially the
toby and greg suggestions to try a second plate on the inlet side of
the rotor, and an inlet tube to minimize the space between the inlet
and rotor.  thank you for these suggestions toby and greg.

we've now built these variations and many others for our 10-11" rotor
@4000rpm solutions.  sadly, there is has not been any great bumps in
vac with any of these.  efficiency may change a bit, but in the
pursuit of higher vac, they are not proving to be worth the effort.

so far the only thing that seems to matter is tip speed.  you get this
through either rpm or diameter, or both.  as we are working with a
power limited 12vdc motor, which will top out rpm wise in relation to
rotor bite, varying rotor bite has quite a bit of impact.

the other surprising impact is seemingly the space between the rotor
and the housing.  one would assume a tight fit between the rotor and
the housing is good.  we've found the opposite to be true.  a 1.5"-2"
or so open space on this rotor size vs .25" has made one of the
biggest impacts on vac potential.

this open space between the rotor and fan housing is typical in the
professional fans you see from cincinnati fan and the like.  i decided
this was counterproductive for vac generation and changed it.   turns
out it is important.

otherwise, we remain topped out at about 8" of h2o with the current
12vdc fan motor.  this is the highest power automotive/truck type fan
motor we can find.

we'll post the actual numbers in more detail soon.  in the interim,
the picture of many of the rotor blades and housing variations are
here: http://gekgasifier.com/forums/showthread.php?p=1664#post1664

thank you goes to nathaniel at apl for running all these tests.

jim

On Sat, Oct 2, 2010 at 7:39 PM, Greg Manning <a31ford at gmail.com> wrote:
>
>
> Greetings Jim, and list members.
>
> Jim, if you want a better fan, (and cheaper), simply make 2 disks (one
> mounts on the shaft, the other has the larger hole for the inlet.)
>
> then use strips of heavy tin (or light gauge metal) and form them into a Z
> shape (well, an L with a dog leg the other end, and the opposite way,
> somewhat like a "90 degree Z")
>
> take these and pop rivet with STEEL rivets (NOT aluminum ones) so they are
> sandwiched between the two disks in a radial fashion (like your welded
> version on your site, BUT with the extra disk on the inlet side of things.
>
> the extra disk should run as close as it can to the outer housing the
> Bernoulli principal will help stabilize the outer disk, and the outer disk
> will add about 25% more suction to the unit for the same RPM (therefore 
> the
> entire unit could be built smaller and lighter).
>
> Greg Manning,
> Canadian Gasifier Ltd.
> Building Hi-Performance Gasifiers, Since 2001
>
> Brandon, Manitoba, Canada
> 1 (204) 726-1851
>
>
>
> -----Original Message-----
> From: gasification-bounces at lists.bioenergylists.org
> [mailto:gasification-bounces at lists.bioenergylists.org]On Behalf Of jim
> mason
> Sent: Saturday, October 02, 2010 4:58 PM
> To: gasification at bioenergylists.org
> Subject: [Gasification] tests to design a new cheap gasifier fan
>
>
> we've been doing some work lately to design a new fan/blower that will
> produce the needed vac and heat tolerance for gasifier operation. as
> we all know, there is not an inexpensive source for such a thing from
> other industries and applications. thus we had to build one for the
> early gek kits.
>
> the original gek fan proved to not be strong enough once we finally
> characterized the vac numbers that produce the flow/heat rates that
> correspond to full tar conversion. the ejector/venturi solution we're
> using currently produces plenty of vac and is very flexible, but
> requires compressed air. this is not good for many off grid
> situations. thus we still need a good fan/blower source. and one
> that works on 12vdc, not an ac source.
>
> here's the info an pictures of our recent tests to produce this. we
> are working towards a much simplified solution that also gets rid of
> the welding to make it. this is based on the common car/truck fasco
> type fan motor.
>
> http://gekgasifier.com/forums/showthread.php?t=455
>
> jim
>
>
>
> --
> ----------------------------------------------------------------------------
> --
> Jim Mason
> Website: http://www.whatiamupto.com
> Current Projects:
> - Gasifier Experimenters Kit (the GEK): http://www.gekgasifier.com
> - Escape from Berkeley alt fuels vehicle race: www.escapefromberkeley.com
> - ALL Power Labs on Twitter: http://twitter.com/allpowerlabs
> - Shipyard Announce list:
> http://lists.spaceship.com/listinfo.cgi/icp-spaceship.com
>
> _______________________________________________
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-- 
------------------------------------------------------------------------------
Jim Mason
Website: http://www.whatiamupto.com
Current Projects:
- Gasifier Experimenters Kit (the GEK): http://www.gekgasifier.com
- Escape from Berkeley alt fuels vehicle race: www.escapefromberkeley.com
- ALL Power Labs on Twitter: http://twitter.com/allpowerlabs
- Shipyard Announce list:
http://lists.spaceship.com/listinfo.cgi/icp-spaceship.com

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