Hot new fan tech goes to 11 !
Posted 01 December 2010 - 05:13 AM
i ordered some samples to test out. here's the doc on the one i'm getting: http://gekgasifier.p...erAssembled.pdf they can manufacture special 12vdc ones too. hopefully they are as good as the doc suggests. we'll see.
the main company that developed these is ebm-pabst in germany. see here: http://www.ebmpapst....?s_17,ss_51,p_2 they have lots of them. all ebm pabst does is make blowers. look at the 3d curved centrifugal blades they have going. very fancy. they've taken things a couple steps beyond where our musings left off.
here's the basic doc on the one we're getting to test.
(2700 Pa = 10.8 inches h2o)
it seems that older one or two speed boiler systems are being replaced with infinite speed variation units for better load tracking and efficiency. these new boilers have also gone to premix systems where the fuel/air is blown in already mixed, and don't rely on late in situ mixing in the combustion chamber. this makes a cleaner burn and smaller combustion envelope, which makes the whole boiler unit smaller.
the ability to premix fuel/air on a gasifier flare helps many things. this is what we do with the ejector venturi and swirl burner on the gek. such is not usually possible with a fan as the flame backs up into the housing and makes a very inefficient turbine (before melting the motor). seems these are designed to not back up flame into the housing. extremely helpful. hope it works with woodgas too.
these new blowers are also usually done with brushless dc, with pwm control built in. the motors are very high efficiency and quiet. they advertise power comsumption in the 1/3-1/2 of what previous gen things do. the performance to amp specs at the link above suggest they are not blowing smoke either.
you can read all about this HOT NEW BOILER TECH in the boiler industry white papers and news releases at links below.
who ever knew fans could be so interesting! (ok, i'll stop now).
Posted 01 December 2010 - 09:33 PM
If these fans turn out to be as good as you hope, and they are as cheap as you say...then I suggest you stock up on them, because with the long-term direction the dollar is moving against other currencies in the world, and since I assume they are foreign-made, they won't stay cheap in dollars. Getting a number of them now is free money.
Just a word to the wise.
Posted 01 December 2010 - 10:36 PM
Posted 16 December 2010 - 07:08 AM
these numbers are tolerable and about what we wanted, though still not ideal. we currently have them down the street with peef to attempt some winding and component optimization to see is we can get a bit more umph and rpm out of them.
otherwise, i'm very impressed. the housing is nicely cast alumimum, with a fabulous full o ring seal. no gas can leak. they are quiet and low power consumption (only 50 watts). eb pabst has done some impressive engineering on these.
the most surprising thing on them is the motor and rotor are soft mounted to the housing. they attempt to keep the vibration from the moving parts out of the housing, and thus out of the boiler closet. i'd never seen a fan with this type of component separation. this comes at the cost of a silicone flex gasket, which will limit heat tolerance.
we're going to see if we can hot rod this 12vdc wound version a bit, then spec back to the maker how to make them like that. if not, we'll go with this 9-11" solution. it's good enough and the best i've found to date.
Posted 13 February 2011 - 10:39 PM
They look like a good possibility... I would sure be interested in getting one or more depending on the price. It is a possibility the gasket material could be made out of some high temp RTV sealant. I have had some good luck with it holding up under heat and still being pliable.
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