grate question

[Bricklayer]

I've noticed in most auf/aof arches that guys have gone with a solid fire brick firebox floor and drilled the brick out for nozzles. Can this be done on an arch just running AUF? I'm using a squirrel cage blower right now. I can probley make some kind of manifold to get the air through the nozzles, would I have to go with a hp blower like in aof to use a grate system like this?

[Bucket Head]

You probably could but you would need more holes, since it's the only source for air. And that air would be at a lower pressure with the cage blower. More holes will feed a larger volume of air.

Steve

[Bricklayer]

Any idea how big of hp blower I would need to get enough air. And how.many holes?

[nymapleguy607]

I can't tell you how many holes would work but I would say make the holes large enough so the don't fill or bridge over with ash. My arch has 3/4" holes. Blower should be around 200-300 cfm.

[DocsMapleSyrup]

Jeff;

I've got a similar situation, but I have a 500cfm AUF blower. How did you support the firebrick? Were they splits or full? What did it take to drill the 3/4" holes. Thanks.

Chad

[Bricklayer]

I welded angle iron flat side up 6" out from all sides. Gives me a full firebrick layed flat all the way around and room for arch board and splits up the side of firebox. If I go with a nozzle type grate I am going to cut a piece of 14 Guage steel with arch board on top to keep it from warping and lay it in first and drill the nozzles holes into that for the manifold for auf. Then if I dont.like it I can remove it without grinding welds. Fire brick drill easy with a masonry bit. Just don't use a hammer drill or it will break. Especially drilling a 3/4" hole

[DocsMapleSyrup]

Than bricklayer. I was going to split 4" sewer pipe and drill it full of holes but from what I'm hearing from other guys is that the stuff is tuff on blades and I don't have the bits to drill all the holes so I'm looking for a better and easier way of doing it.

[Bricklayer]

If I do go with just normal grates and stay with my squirrel cage blower I am going to get a tin banger at work to make me a small plenum that is the same size as my grate opening. Then either drill holes in that or cut 3/8" channels in it to line up with the grate openings. For his shop to make it it's $25. I'm sure if you wanted to add a hp blower to this setup then instead of slots in the plenum you could install nozzles. Then just put arch board and bricks over the plenum. Might need a support or 2 in it to support the firebox weight. I will post a pic when I get mine if I go that route

[DocsMapleSyrup]

I finished my grate today. I used 2x2x1/4" angle with the V open at the top. I will fill them with ash or sand and cover them with brick. The bricks line up so that the AUF will come up between the grates and will exit out the fire brick on top of the grates through 3/4" holes in the brick.

[Bricklayer]

Can you post some pics of it?

[DocsMapleSyrup]

Here's what I ended up with. The brick's holes will line up between the grates. The entire grate system sets on the rails but is elevated so I can remove it if needed. I don't have any photos just of the grate but you can see the concept in the photos.122121221312214

[DocsMapleSyrup]

Oops. Don't know how to rotate photos

[Sugarmaker]

feychad,
That may work well with the bricks on top. Keep us posted.
Regards,
Chris

[Bricklayer]

Would this setup work with a squirrel cage blower for AUF. Or would the holes in the firebrick get plugged with ash?

[DocsMapleSyrup]

I'm hoping it will push are through the bricks. If it doesn't, Ill rearrange my high pressure blower and run it underneath as well. I do know that when I visited Smokey Lake Maple, their arch floors were split sewer pipe without air space between them but with 3/4 inch holes drilled in them and a squirrel cage blower for AUF.

[Bricklayer]

So the grates were cast iron sewer pipes? What diameter.? Just trying to imagine that. And how was the blower set up. Just blowing into the back of the arch? Or was there something to direct the air up through the grates?

[DocsMapleSyrup]

The pipe was 4" cut in half lengthwise and laid with the dome up. Holes were drilled into the pipe. I didn't pay much attention to the size but I would imagine 1/2-3/4". After getting a piece of pipe, and attempting to cut it and a pilot hole, I gave up. It's not easy to work with. Here's what I ended up with. As to the AUF question. A squirrel cage fan is what Smokey Lake attaches directly to the back of the firebox. You can see it on their Silverplate evaporator photos on their website. That motor blows air under the pipe and out the holes. Jim said it would put out 80 gph with the hood and preheater with AUF only and stack temps around 1300 degrees. They don't produce a unit with AOF in the 2' wide evaporators. I'm adding a AOF to improve wood burning efficiency, went with a longer firebox, and am hoping to reduce the stack temps as a result. You'll notice that I still have to pull the fire grate and put the sheeting in the firebox floor;

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