Adventures with a horizontal feed

[satamax]

Aug 28, 2012 23:30:37 GMT -8 docbb said:

Peter do you think the metal part of the "P"channel matters?
did I say "plasma"?

Have you seen any change in the iron plate, like transforming into a magnet ?

Docbb, iirc, metal demagnetises with the heat, not the contrary.

[peterberg]

Sept 7, 2012 8:51:12 GMT -8 satamax said:

Peter, two other questions, would increasing the flow speed be beneficial? I'd like to make the entrance into the heat riser tangential, so it spirals instead of "ram horning" ;D

There's one thing I've found out during me wrestling with tangential feeding. As long as the flame is following the circular wall, the burn is relatively clean. But once the flame won't follow the wall and go more or less straight to the exhaust, you're stuck with a dirty burn.

On the other hand, my setup will burn clean in 3 minutes, utilizing a very weak draft. It will burn clean already when the flame is straight and short. My point is, the ram's horn pattern is just one of several conditions during which a clean burn is obtained.

Sept 7, 2012 8:51:12 GMT -8 satamax said:

Another thought, i wonder if rounding the bricks edges around the "venturi" wouldn't be beneficial too!

Maybe yes, maybe no, I honestly don't know. My guess: it will make very little difference.

[satamax]

Hi Peter, thanks for your replies and patience.

With such à contraption, what would be your opinion, 6 or 8 incher? Or more?

I have a 36 suare metres flat. A huge 50 or 60cm wall and the chimney (brick duct) about 11m high.

What do you reckon?

Thanks a lot.

Max.

[peterberg]

Sept 8, 2012 2:20:43 GMT -8 satamax said:

With such à contraption, what would be your opinion, 6 or 8 incher? Or more? I have a 36 suare metres flat. A huge 50 or 60cm wall and the chimney (brick duct) about 11m high.

You're living in the Alps, close to the Italian border. The region of Briancon perhaps? Can be very cold in depth of winter. You mention the thickness of the wall, so there's no insulation in there?

With the stoves in mind I've seen here, a batch box rocket of 6 inch system size would be probably too much for a 36 square meter apartment. Please build a simple trial version outside, when you still can. This will tell you how powerful this thing will be. Much, much more than the 6" RMH "by the book". This is because it will burn a larger amount of fuel in a shorter time. The combustion efficiency is very high.

[peterberg]

Largely as the result of a lot of talking to some people at the demo location I've changed the way the p-channel is constructed. Instead of a U-shaped piece of steel, it's a piece of small rectangular duct now. Plus a simple horizontal channel running over the top plate of the stove. More or less analogue to the layout Canyon and Donkey used at the start of this thread.


High res:

No problems with fixing it in place, because it's just lying there. It's welded to its vertical part, forming a simple L-shape. No leaking from the sides as well, it's a closed duct.


High res:

In order to get the right overhang, I've cut out a small piece out of the back side of the vertical part.


High res:

This way, the whole channel is a single piece. Running the stove like that, the horizontal part won't get hot at first despite it should conduct the heat out. Cooled by the incoming stream of fresh air. When there's the occasional puff of smoke, it will be largely sucked into this channel. Later on, when the top plate gradually warm up this will take up some heat as well.

I've let it run this way, a piece of Neoceram glass and some bricks in front. The total opening, one at front bottom and the other at front top summed up to a little bit more than a quarter system size. Could be less, I presume, maybe even skipping the top opening. Size of the p-channel is exactly 5% of system size, by the way. The stove's been loaded full, little bits and pieces. And this is the result.


High res:

Not bad, not bad at all. My only actions during this run: closing the top air entrance at 24 minutes and poking very carefully at 30 minutes to counter measure the bridge-forming of the fuel. The impact wasn't very important or long lasting, as is visible.
Averages of this successful run: O2 13.5 %, eff. 77.7 %, CO 685 ppm, Tr 227 C.(441 F.)

One important aspect has been coming clear during the last week: the riser has to be very uniform in shape and c.s.a., otherwise the stove won't reach its maximum burn rate. So a change of a rectangle to a circle is not done, irrespective of the c.s.a. being the same. Moreover, the lower this change in shape will be situated, the more the stove will slow down.

[satamax]

Hi everybody.

Peter, i live 15km away from Briançon. The outside walls are insulated, a bit. This is inside load bearing wall. No insulation, and all the chimneys of the 3 flats on top of each other running through it. A 6 incher batch load being too big? Heyhey, i might try à four incher! The french 111mm stove pipe costs nothing. I need to buy some vermiculite. Two things, you said, the batch box needs to be taller than wide? Or square would do? I can do a V shape bottom.

What i envision right now, landini or tomason sell square refractory tubing

Check page eight. One piece of 25x25, i know they have some at blanchet, next door. Place it horizontaly. Cut a semi circular shape at the end of top back edge. Cut a slot in the vertical refractopry tube. Big prob, they only have 160mm as the smallest round. Tho, i can order 120mm. www.landinispa.com/landini/resources/user/file/Listino_camini_argilla_eurogas_comignoli_legante_n39_pr17_rev1_maggio2010.pdf

Again on page 8. I'off to sketchup my idea.

[satamax]

Something along thoses lines. I would let the back around the tube fill up with ashes. One metre heat riser, could do 1.5m too.

Attachments:

[peterberg]

Sept 8, 2012 8:02:33 GMT -8 satamax said:

Something along thoses lines. I would let the back around the tube fill up with ashes. One metre heat riser, could do 1.5m too.

OK Max, this could be done. Not sure about the fireproof qualities of the chimney parts. A couple of corrections if you don't mind.

The V-shaped floor isn't any good like that, make it 45 degrees, that's enough. What you propose will be prone to bridge forming, the fuel will "hang" and underneath the burn could stop this way.

The back of the riser will not fill with ashes by itself. Maybe you could do that another way, because the lightest ashes will go up in the riser to whatever you have there to catch the heat.

I'm entirely unsure about the effect of the cylinder inside the firebox. It could be beneficial to have half of the cylinder inside and the other half protruding out the rear. It will probably run without any insulation, but for prolonged burns it's better to have it around the back end of the firebox and the riser.

Proportions are nice, firebox front is about 3 times the riser, opening is 70%. Maybe I would make the tunnel opening a little bit higher and narrower, perhaps even a bit smaller, say 60% or 65%. The length of the riser above the tunnel is about 80 cm, that should be perfectly adequate.

Are you implementing a p-channel as well or are you going to use this as an open fireplace?

Edit:
As an afterthought: it's best to make a little slope at the back of the riser. This way ashes won't collect easily. I know, this is difficult in a cylindrical riser.

[satamax]

Hi peter.

Well, i'm trying tu use the refractory parts available to me. But sure i can do a vermiculite/refractory castable mix at the back to enclose the the bottom of the heat riser. Or even vemiculite, and a thin layer of castable in front. It's perfectly possible to do half in half out too. The heat riser tube is 160mm ID. If i use smaller, i would have to order. I might pop round the suplier on monday. I already have one piece of tubing. And used another one. They're tough. It's the same stuff as firebrick, only tougher imho. You're giving me food for thoughts. I was thinking of using a P channel. But i'd rather have an open front. Thought if i can put glass in front, that would be as good. Do you think this system can push much horizontal tube lengh with the draft created by the 11m of chimney? I'd say yes. I think i can do about 5 to 7.5 or may be ten metres of horizontal tubing. Depending on diameter of the tube. I have access to cheap'ish aluminized steel. In 111mm, 139mm and 156mm. I have no clay over here, so i was thinking about sand for teh mass. Yes? No? I know the general consensus is sand is not that good. Well, you got me seriously thinking.

[matthewwalker]

Max,
My neighbor used sand for temporary mass on his RMH, and it was unsatisfactory to say the least. Once dry, it was a very good insulator. Maybe just rocks and your local dirt to fill the gaps?

[satamax]

Thanks a lot Mathew. Well, rocks, i can get aplenty. It's the infill in between which is the problem. No clay over here. I'm at 1500m, in glacier land. And the mass will have to be removable, for whenever i need to move to my home. May be cast concrete around the tubes, something like 8"x8" or 10"x10" by 6ft long. 260kg to 204kg each depending on tube size, either 111mm or 156. X4. Well, that sounds like a fair bit hey!

[peterberg]

@max,
So you're in glacier land, 1500 meter above sea level, about 15 km from Briançon and close to the Italian border. Let me guess... maybe your residence is located in the Vallée de la Clarée, maybe even Plampinet? I am cherishing good memories about that valley, more specific Névache and Fontcouverte.

Oh those days... however, back to business. The chimney length you'd mention will create a draft of about 0.05 to 0.10 mbar. That's excellent, and enough to let the batch box take off. But, perhaps your chimney is one of those horribly wide and antique French channels, very rough inside and lots of mass. In case I'm right, before you'll build anything else, insert a stainless steel flexible duct and fill up the rest of the space with vermiculite. This way, you'll be able to feed a horizontal duct of nearly ridiculous length without a problem at all.

[satamax]

Hi Peter.

Well, next valey, serre chevalier, the top resort called Monetier. Just next door. But doesn't change any, there's no clay The chimney actualy has a lot of mass, but, is smooth as à baby's but, being earthware. Refractory or not? Dunno! I can't tube it. I've tested this morning, and i have a nice draft. With the miror, i can see light on top, so it's straight, and it's 50+cm above the apex of the roof. I don't want a ridiculous lengh of horizontal tubing, i don't know what to do for mass. It has to be removable with minimal effort! When i get permission to build my workshop and flat above in the industrial estate.

What about concrete flower pots for mass? What do i fill theses up with?

Or may be stuff like this?



It's always the same, how to get good contact between mass and tubing? When you have no clay.

[peterberg]

Sept 9, 2012 7:37:14 GMT -8 satamax said:

Well, next valey, serre chevalier, the top resort called Monetier. Just next door.

What a disappointment... ;D

About the chimney, how wide is it? Smooth earthenware is alright, straight also.

Now about the bench or whatever. Maybe you have to treat it as a bell containing less mass. The supplier of those chimney liners, doesn't he sell large square ones made of cheap earthenware? You could use these on its side, the only problem is how to get it airtight.

Or, you could think of building one or two upright bells from those liners beside each other, feeding and exhausting at floor level. With superwool between the parts instead of mortar and closed off at the top with a refractory plate or something like that. You could even place the batch box rocket in one of the bells. Easy and quick to build, and certainly movable.
How does that sound?

[satamax]

Ney bad an idea Peter, ney bad!

I didn't think of this!



Two stacks of thoses behind the actual stove, aranged in a bell, and i'm done.

Flue from the barrel, into the bottom of the first concrete flue stack, then from the top of this one into the top of the second one, then from the bottom of the second one into the chimney. What do you think? With your ideas, we'll end up knowing every trick to make cheap rocket mass heaters