Re-constructed fire box design

Pics 10 - 11 of secondary air

Pics 1 - 3 of new grate

Pics 4 - 5 of new grate.

Your "old" pics look like the firebox on my boiler!

I think you may have about 20% more heat with that setup. My only concern is the rebar, I don't think it will live a long time. I would be on the lookout for a cast iron replacement. (cast iron catch basin grate?)

Nice work rich! I have a few questions, the old grate looks like it rocked left/right around a center shaft. What shaking action will the new grate have?? Will it slide for and aft?

You did a nice job securing the firebrick, the steel looks like possibly stainless, or maybe cold-rolled mild steel.??

For the heated secondary air pipe in the base of the fire, is this regular black pipe? or is it cast iron pipe? I found that the pipe in my attempted secondary hot air system deteriorated from the heat very quickly. I was trying to find some Stainless or cast pipe, but never found it.

Berlin uses rebar for his grates with good success, but I think he has the top layer of rebar at 90* to the motion of his sliding shaker mechanism. the bars at 90* act like teeth on a very coarse file to shave off the stubborn ash on the bottom of the coal pile.

Do you have air being forced through the secondary air pipe? or is it drawn by chimney draft??

I'm looking forward to hearing about your new improvements in use!

Greg L

You may want to run the secondary air pipe through the back wall overhead. Keeping it way above the fire and much cooler should prevent its deterioration.

Hi Ian, actually the secondary air has to be heated very hot to burn the soot and volitiles coming off the Bituminous coal. I tried just introducing outide air, it didn't work.

With the heated air, the effect was like a blowtorch, the soot/volitiles turned into an amazing amount of flames. I guess the cool outside air dropped the temp too much to allow ignition of the fumes.

Greg L

That makes sense. Maybe a loop around the top prior to venting? That pipe in the coal fire can't last long.

Hello Greg,
The old grates were cast iron and did shake left to right on a shaft. I had a problem with handle keep braking on me. When a clinker got caught I would try to shake it and broke the handle off of it numerous times. I welded it back on and it just broke in a different place every time. The new shaker grate slides from front to back and not side to side like Berlins. I have a total movement of 3 - 4 inches of slide to break up the clinkers. I wasn't quite sure how the grate was constructed from Berlins design and he was suppose to get me pics of it, but it is starting to get cold out and I didn't want to wait till the dead of winter to start the changes so I couldn't wait any longer. The angel iron holding the brick is 1/4" 3" X 2" stainless. I have the angel iron wleded to the front of 1/4" plate which is how I made the walls vertical. I've lost a lot of space from doing this modification, but hoping that it burns much better this year. The secondary air pipe is regular black pipe and not forced air. I'm relying on the draft to bring the outside air in. I'm hoping that it doesn't deteriate all too fast. I'm not sure of the thickness of it, but it seems like it should last a while? Thanks for your input!! Is there anything that you can see that is missing that I can do to make it burn better?

...Rich

Hi rich, nope, it looks pretty good, you might try finding a small fan to force air through the pipe, this might keep it cooler. Since you don't have this in the current setup, you must have inlet holes in the bottom pipe to draw air in from below??

With the vertical sides, the firebox will work much better, you should have fewer clinkers, the coal should bridge less, and burn down to the grates better. It now looks like a 'real' coal stove, not a compromise wood/coal firebox.

Looking good!

Greg L

Greg,
So in order for the secondary air re-burn system to work you're saying that I need holes in the bottom pipe that runs through the coal bed? how big and far apart should these holes be? what are the chances of them getting clogged by the ash? Thanks for your input. I'm not sure what I would do if it wasn't for you and all of the other informative members of this site!! People like you make life a lot easier easier for us less knowlegable coal burners!!

...Rich

HI rich, where is the air getting into the pipe now?? I assume you have drilled some holes in the upper pipes to distribute the heated air over the fire.

I see a threaded on cap on the external part of the pipe, is this where you planned on getting air into the pipe?? Or is it just capped off here?

I was thinking of some holes drilled in the bottom of the lower pipe where the air from the ash pan would enter through the grate. I don't think ash could get in from the bottom. Or, if you plan on letting air in via the capped end, that will work too.

Greg L

LsFarm wrote:I was thinking of some holes drilled in the bottom of the lower pipe where the air from the ash pan would enter through the grate. I don't think ash could get in from the bottom. Or, if you plan on letting air in via the capped end, that will work too.
Greg L

External air from the capped end will work best as you will get the most pressure differential between the outside of the stove and the top of the firebox - hence maximum airflow potential. If you use the ashpan air, you've already lost pressure due to the restriction through the draft control and it may not allow enough airflow to do any good.

My $.02. Basically I'm using Berlin's plans for his bituminous burner as a guide.....

Chris

I was thinking air from below the grate because rich's stove has a forced combustion fan on the ash pan door. So the area under the grate should be under pressure when the fan is running.

I made my secondary hot air set right on a gap in my grate, it had a forced combutstion fan pressurizing the ash pan area. It worked well while the steel tubing held up.

Greg L.

Good point on the forced combustion air, Greg.

Definitely be a good thing if Rich could find some stainless tubing, or he'll be replacing that steel tube pretty often, no?

But, stainless will be $$$$$ and a bugger to drill.

Chris