|
Post by daniel on Nov 16, 2015 23:47:54 GMT -8
Hi Exo, the bells looks good, I am a little worried about the cold joint wall that sits above the firebox, how well it is supported, etc. With a single layer of bricks and on edge there could be hairline cracks in the mortar here and there. I would plan on another layer of high temp plaster just to make sure you don't have any leaks in the long run. I tried to avoid cold joints wherever I could and let the firebox float independently of the rest of the stuff around.
|
|
|
Post by dustylfc on Nov 17, 2015 8:03:10 GMT -8
How far into the 2nd bell will the 8 inch chimney sit ? Going by the pick will sit within the bell ?
|
|
|
Post by exoplasmic on Nov 17, 2015 10:40:06 GMT -8
To Daniel and Dustific Daniel, The bricks on top of the firebox are for aesthetics only. They should never touch smoke. They touch, barely, the side walls, but there are a lot of gaps. I plan to stuff rock wool in those cracks and fill in the space between the facade and the firebrick with perlite. That way it might make the heat riser hotter and more efficient burning the wood gases and semi volatile tars and such. Recall that at the top of the heat riser is a floor that extends outward in all directions. The only bricks that will get hot are the fire bricks above the floor (12 inches between "floor" and ceiling).
Dustific I hope to put the metal chimney about 1 foot from floor, right in front of the clean out door. I will put a couple loose bricks between the opening from the 1st bell so that the heat is directed upwards and not directly into the chimney. I can remove the bricks for cleaning ashes. If I had thought about this before, I'd have made the bell longer so the chimney wasn't right in front of the flow of exhaust.
When I build the nice heater for the main floor I'll make a lot of changes. Maybe I'll find the metal firebox is a mistake. But, right now I sure like how sturdy the door slams shut and locks. I'm rough on things and prefer sturdiness more than most people I know.
Mike
|
|
|
Post by daniel on Nov 17, 2015 11:13:40 GMT -8
Nice, I ended up encasing the box into the bell since I did not have to insulate it, the firebox would be in the hot area of the bell and would also help the burn with its heat as I see it. Also a very important reason why I chose this is because of the simplicity of the design. I used to and still think in a perfectionist manner but try to make it simple and efficient. From this perspective I encourage you with your project. As far as the cleaning of the bricks if you used clay that would be easily washed with a sponge in a rotating motion. If it is dried first wet it. Also if it is dry you could wet it a bit and brush it off with medium bristle brush in a rotating motion.
|
|
|
Post by dustylfc on Nov 17, 2015 11:32:45 GMT -8
Just thinking of the chimney / flue would it be easier to run it on outside of bell For ease of maintenence if any ? And would it make a difference to the way it performs? ?
Not criticising just wondering
|
|
|
Post by exoplasmic on Nov 17, 2015 16:02:34 GMT -8
Dusty Yes, I think it would be easier to run it outside.
At first I was going to have a small brick box on the floor with the chimney out the top of it, right in front of the clean out door. But then I thought: why not make the box into a 2nd bell?
I wish I could have found a plan online for a batch rocket heater with 2 bells. Something verified that I could copy. But nooooo, I had I experiment with my own design. It's in my nature to do it my own way and learn by making mistakes. Oh well, c'est la vie!
As to servicing the chimney: I think the chimney sweeper can fit into the clean out hole as long as it is semi-flexible to make the turn up into the chimney. I imagine the sweep is like a drain snake for unplugging sewage pipes. I'm guessing it has a brush that rotates as it gets pushed up the 34 feet of chimney. Hopefully I'll get clean combustion and I won't have to sweep it often.
I may need to disassemble the chimney sections for more serious service. But those are connected by 4 screws. The slab ceiling tiles of the bells all float on top of rock wool gaskets.
I haven't cast that final slab with the 9 inch hole for the chimney. I hope to measure it tonight. Build the mold tomorrow, paint it with latex paint to seal the wood as a non-stick surface, then cast it the next day. 24 hrs later I can place it on top of bell #2. Then light this baby on fire.
|
|
|
Post by daniel on Nov 17, 2015 23:23:41 GMT -8
as far as the chimney sweep goes there are a few ways to do it, reach from below with a semi ridgid cable and a flexible bristle brush, from above with a weight and a brush attached to a chain (the way I do it) and I have seen a chain fixed permanently inside the chimney (this works well for metal chimneys I don't recomend for refractory chimneys) which you grab and shake around.
|
|
|
Post by exoplasmic on Nov 24, 2015 12:58:45 GMT -8
Finished. It drafts great.
I've been gradually increased the size of fire over the last couple days. I'm at medium small fires. Tonight I'll start a medium size fire and try to keep it at that size for at least 2 hours. Am I worrying too much about steam blowing up my casted parts?
I saw steam from the fire box prisms (2 sloped bottom lengths) where the red hot coals were touching the sloped side right next to the air hole in front. The steam eventually stopped coming out so I increased the size of the fire. The one part that cannot have a break is the heat riser. If that part has a major explosion of steam and mortar I'd have a hell of a time to repair it.
|
|
|
Post by exoplasmic on Nov 25, 2015 3:32:30 GMT -8
|
|
|
Post by exoplasmic on Nov 25, 2015 3:33:44 GMT -8
|
|
|
Post by daniel on Nov 25, 2015 8:01:50 GMT -8
Looks good, is the P-channel going to be insulated? You should have no problem with the casted parts if they were dried when you put them in and if the water quantity was according to instructions
|
|
|
Post by exoplasmic on Nov 25, 2015 9:02:45 GMT -8
I'd like to insulate the p-channel but I can't think of anything that makes sense. It would eventually heat up if I put a layer of bricks on top of the firebox enclosing the p-channel. That's if the brick got hot. The p-channel is not touching the hot metal top of the firebox except at the back, and that's above the refractory ceiling of the firebox.
I'm going to get hot air through the p-channel somehow, but I don't know how yet.
So that's a flaw.
Another flaw is no damper. However, the guy who put my chimney in has one for my pipe size. He said he'd drop it off on Friday. Luckily my chimney pipe is adjustable so I can slip it it without too much trouble.
|
|
|
Post by daniel on Nov 25, 2015 9:11:52 GMT -8
The air will be drawn in, you don't need to do anything to get it through, just insulate so that the air it will get warmer. The air does not need to be extremely hot just preheated, if the firebox has only metal above it will heat it too much and it will have difficulty travelling downwards in the box. As insulation you could put some firebrick, rockwool, perlite etc.
|
|
|
Post by peterberg on Nov 25, 2015 10:55:20 GMT -8
I'm going to get hot air through the p-channel somehow, but I don't know how yet. So that's a flaw. No, it isn't. Provided the p-channel is like the original design there's a vertical piece of about 4" inside the firebox. That will get awfully hot so the air will be preheated, rest assured. Also, the rest of the duct could get warm by conduction of the metal duct. Try with a lighter when the thing is running, the flame will be sucked in. All caused by the Bernoulli effect which predict the pressure in the port is lower than in the firebox or the riser. As long as the chimney pull is going there will be an underpressure in the port and in the p-channel as well. Lots of people ask me why there's no smoke back through that duct.
|
|
|
Post by exoplasmic on Nov 26, 2015 7:37:43 GMT -8
Thanks Peter. So i may shorten the p-channel so I can put a kettle on top of the stove. Here's what the fire looks like at high burn rate. www.dropbox.com/s/br14iu1i4pjsqxs/2015-11-25%2018.34.06.mov?dl=0It seems to be an efficient burn because the visible emissions from the chimney seem to be showing water vapor and no smoke. I'd show a video of chimney but it's raining now and 48F (9C). Happy Thanksgiving! Family, Food and a warm house. Peace to all you Rocket Stovers!
|
|