corn stove combustion fan

Does anyone know how big the combustion fan is in a corn stove?

Obviously it is dependent on the size of the unit, but I am trying to determine how big(CFM) the fan is.

I am considering building one myself, but am unsure as to what sort of airflow they are creating. I would guess it is 40-50 cfm, but would not be surprised to learn it is much higher.

Any ideas?

thanks

JW

Reply to
jw
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Diameter and pitch should do it for volume

Reply to
wws

I've been playing around with the same thing. I know they are using a blower to speed combustion, but I'm having trouble making it work.

I made a little burn box (2" diameter pipe, air supplied to the bottom) then I applied air to from my air compressor. I adjusted the air flow with a ball valve. Then, I attempted to light the corn with a propane torch. Regardless of the volume of air, I couldn't get it to light. Then, I took a 6" pipe and started a wood fire in it. Applied corn to the existing fire, and it burnt quite nicely.

Let me know what you come up with.

Reply to
Dave Lyon

???

diameter, pitch of what? Wouldn't speed be relative as well?

Diameter would be easy enough to measure, but how do you determine pitch of a fan blade?

JW

Reply to
jw

Get a flat surface under the fan... ie piece of sheet metal etc. Measure the angle of the blades from this flat surface = pitch

Another idea is to go to a shop that sells them and ask for the information as if installing.

Reply to
Greg Krynen

This assumes that it is an axial fan. Also that it is possible to get to this without dissassembling the unit.

What I have seen are generally squirrel cage fans.

JW

Reply to
jw

The combustion air flue blower even in a 100,000 BTU/hr furnace is not very big. I'd guess that 50 cfm would be plenty for a corn stove, probably would need to be throttled some.

Reply to
Don Foreman

Sounds good. I was planning on throttling it via a PWM and/or some other driver circuitry. Damper doors would also work, but would be harder to control automatically.

Eventually I plan to develop a controller for this so that it is relatively automatic in regulating itself.

Does anyone have any idea where to source a small(2") auger to be used for the feed auger?

JW

Reply to
jw

Look in the garden stuff section of a big-box store (like Homely Despot). They sell small augers for planting seeds, intended to be drill-powered. Cheap, even.

Reply to
Fred R

Cannibalize a pellet stove? For that matter, anyone ever try burnin' corn in a pellet stove? It's already got everything you'd need.

Snarl

Reply to
snarl

4" is quite common in soils testing equipment. Gerry :-)} London, Canada
Reply to
Gerald Miller

If I had a pellet stove to cannibalize this would all be a relatively moot point.

Around here they are not available new(6-8 mo waiting list). Used they are just as scarce(or expensive).

JW

Reply to
jw

My guess is that the blower is much smaller than 40 cfm. W.W. Grainger sells a high efficentcy gas furnace that outputs 94,000 btu/ hour that has a 2 inch diameter flue.

Dan

Reply to
dcaster

Where are you located?

Out here in th' PNW there's tons of 'em, cheap, if one looks around a bit. There was one in Craigslist that sold for $50 a couple weeks back. I've seen 'em free in there as well.

It took a good friend of mine 4 months to give one away. It worked perfectly. Th' guy who took it removed th' auger and other bits to build a Traeger style smoker bar-b-que.

Snarl

Reply to
snarl

Hi JW,

There are quite a few manuals available in pdf form that you can download. This one is interesting, but I didn't see the CFM value listed for the combustion fan. Lots of good general info though:

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Take a look at this google search:

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I looked through a few manuals, but I didn't stubble across any CFM values. Most of them seem to use variable speed fans/controls for what it is worth...

Reply to
Leon Fisk

I can't give you a good answer, however, my son is currently in the process of replacing the fan/motor in his pellet stove. The fan is a disk of approximately 6" diameter, with radial vanes on it, however, the vanes are only about 1/2 to 3/4 "wide" with a little lip on the outside edge to kind of catch and hold the air that it throws. There must be about 14 or 16 vanes. The motor is marked at

3100 rpm. However, there *is* a damper of sorts to control the amount of air that flows. The fan in on the "output" side of the fire, and draws air into the stove through about a 1-1/2" tube, then up through the fire, then into the fan chamber and finally blows the exhaust out the vent pipe. I believe it is set up this way to keep a negative pressure on the door gasket, etc. The damper is on the input side to the firebox and can throttle down the amount of air needed to make the fire burn well. Hope this helps. Ken.
Reply to
Ken Sterling

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