[Gasification] tests to design a new cheap gasifier fan

Arnt Karlsen arnt at c2i.net
Sat Oct 2 20:41:43 CDT 2010

On Sat, 02 Oct 2010 19:58:19 -0400, Alex wrote in message 
<4CA7C71B.9000301 at kingston.net>:

> Hi Jim,
> We did something similar to make a high temp blower. We grooved the
> hub and backing plate to set the vanes in. Then countersunk holes in
> the back of the grove to weld through and then grind smooth.

..welding means it bends, on my 2'nd wheel I used rivets.

..I have strong reservations on "hanging" fan blades 
"on one side only", when they can be hung on 2 sides.

..spin up a fan wheel and play with a stroboscope and
watch the fan wheel _bend_. ;o)  
Once an inner spot weld gives way, mayhem and fan parts 
heeds the 9/11 Flight 93 battle cry "Let's roll!", and
on _your_ ass.

..hanging the fan blades on 2 sides simply means weld on 
"another wheel" around the inlet hole so air can enter the 
fan wheel channels formed by the fan wheel walls and the 
fan blades. 

..spinning it up, means both wheel walls stretch by about 
the same amount, which again means the fan blade loads will 
be carried by both wheel walls and bend the "back wall" a 
lot less than with your current 1-sided fan wheels.

..bonuses includes less air friction and less air leaks 
over the fan blade edges, as air is trapped by the front 
wall, which means higher pressure from the same size fan 
wheel at the same speeds.

..disadvantages: a bit harder to clean, especially with 
bent fan blades, (I've only done straight blades) and
a large diameter bearings around the inlet is needed 
if you wanna support the wheel "at both walls."

> What is your temperature target? What will the needle bearing
> tolerate?
> Thanks for sharing it.
> Alex
> On 10/2/2010 5:58 PM, jim mason wrote:
> > 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

..med vennlig hilsen = with Kind Regards from Arnt... ;o)
...with a number of polar bear hunters in his ancestry...
  Scenarios always come in sets of three: 
  best case, worst case, and just in case.

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