Prill combustion air

So I'd still use a thermostat, but the repeat cycle timer would only allow the stove to run X percentage of the time the t-stat was calling for heat? I hadn't thought about that. Might work too.

Got to thinking though - my fan and stoker are run off the same motor. I'd still have to separate the two, so that I could still run the combustion air after the recycle timer turns the stoker off. This is complicated.

Steinke, can you mount a small jackshaft and double reduce the belt ratio ?? I don't have a mental picture of the drive motor and gearbox relationship, can you post a photo??

You could add an auxilary fan that blows into the inlet of the existing fan, this would force air through the fire even when the coal is not being fed to the pot.

Greg L.

ALL:

I always thought a separate motor for the fan and the feed made a lot more sense than

a single unit,way more flexibility. A small blower is all thats needed,with the feed circuit

the cyclic timer using the feeder you already have,maybe even a rheostat on the fan or

even simpler a flapper gate on the blower inlet to limit the air flow.This setup gives almost

unlimited control of the fire.


BigBarney

Your work sounds very interesting to me. I also purchased a used prill 100 furnace this summer. Have installed my new chimney. I was told that this unit will also burn wood pellets. I will begin installing the furnace on monday, so have all the bugs worked out by then so you can walk me through my install (if it were only that easy).

I hope you get your flame out of your chimney....chimney fires are deadly.

I live between the Utah and Wyoming mines and have yet to purchase coal....going to experiment with coal from different mines.

We really need to talk. I have other install instructions from the mfgr. Its late, I'm tired, but I will watch the thread and for messages.

the repeat cycle timer would work, but you'd still be losing efficiency. the furnace will operate (and produce less soot) when it's firing for longer periods of time and thouroughly heat soaks the heat exhanger. greg is absolutely right, you don't want the flames contacting the metal; if you think you have too much air, you probably don't, open it more. i'd separate the air/stoker drive motors, i did it on mine and am happy that i did. switch the pulley on the gear box AND the motor to obtain the lowest feed. i don't know what size motor drive shaft you have (and can't remember what mine is either right now) but i found pulleys at the local hardware store as small as 1" for mine. i'm using about 1.5" adjustable pulley currently.

Not sure what Greg means by "mounting jackshaft and double reducing the ratio". Do you mean adding an idler pulley so that I'm not wrapping the belt as sharply around a smaller motor pulley?

The motor shaft is 5/8" keyed. Smallest pulley I can find is 2" diameter with that size bore. 1" would be good to try, but I can't find one. I think my gearbox pulley is about 6" diameter, I could only go to about 7" or maybe 8" before i ran out of room. Moving from a 6" to an 8" pulley isn't going to change things much.

Attached is photo of the factory setup, with my 2" pulley added.

I hate hacking on the stove. I'm pretty slow and cautious.

Steinke

Steinke, you have a lot of room.. and you won't have to use a jack shaft.. I'd buy a 8" pulley.or larger, it looks like you have room for larger... from 6" to 8" will be 33% decrease in the stoker shaft speed. I think my math is correct..

A jackshaft is a separately supported shaft with in your case, probably a 4" pulley driven by your motor, and a 2" pulley that then drives the stoker pulley,, this would give you a 1:2 reduction in the stoker rpm. with full speed on the motor and fan. You would need to make a bracket to support two pillow-blocks for the jackshaft to run in, and some slotted mounts for belt tensioning..

But I'd try the larger stoker gearbox pulley first, it is the easiest and quickest to try.

Greg

Greg, could he swap the pulleys? Large on the motor, small on the gearbox, or would that be too hard on the motor and slow the feed down too much?

rockwood wrote:Greg, could he swap the pulleys? Large on the motor, small on the gearbox, or would that be too hard on the motor and slow the feed down too much?

Big pulley driving little pulley will increase the speed of the driven. I think he is trying to slow it down.

Gambler is correct, Steinke needs to slow the stoker gearbox, probably by 1/2 would be about right.. but the motor which runs the combustion fan, needs to stay at full speed..

Greg L.

.

Right. What a dummy, I don't know what I as thinking.

Well, I really don't have room to put a bigger pulley on the gearbox. The current gearbox pulley is 6" dia. I only have about 3/4" between the pulley and bin wall. So I cannot fit an 8" pulley, and I don't think I can find a 7" pulley (not to mention that it wouldn't change things much).

So I guess I'm going to try building a Jackshaft. I've got some ideas how to do it now. Headed back to Nebraska to my parents farm for Thanksgiving week, where I have access to lots of tools, welders, mills, etc. I'll get something fabricated and post back with the results.

Thanks for your help.

Steinke

Steinke,, can you mark the 'bin wall' where the pulley is close?? and remove the bin wall and take it with you?? I'd cut a 2" wide slot in the bin wall and put a curved insert/cover in the slot.. you'll have to fabricate the curved cover.. this would give you lots of room..

If your choices of pulleys are made from aluminum, chuck one in a lathe and turn it down to a smaller diameter.. Making a nice 'V' on the lathe may require making a special cutting tool, but it can be done.. I'll look and see what my local hardware has.. I may be able to turn down a 2" or 1.5" aluminum pulley for you and mail it to you.. you said 5/8" shaft, with keyway right??

Snow fluries today.. I guess winter is here..

Greg L

My solution would be to remove the gearbox drive from the existing motor and hang a variable speed motor under the existing motor which would belt drive the gearbox.