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Post by salamandre on Oct 15, 2018 12:45:45 GMT -8
Hi, First of all I am french, so excuse me if the english is approximate. I have the project to build a rocket batch box 150mm with barrel and piped bench of 5m. The construction must take place next weekend. So i have made a model and start a fire inside. I think that the fire is not very strong and that there is smoke. You can see the picture with the link above. www.dropbox.com/sh/nxdp3wnbr2fd3te/AAAHbxcRHZ3Ryqg29eXWJxbla?dl=0I respected the measures, put a cobra at 15mm of the port. In first i started the fire with the little wood (5 or 6 pieces of 2 _4 cm of diameter) and after i put larger piece of wook that you can see on the pictures. May be i did not put enough wood to see the double vortex or the operation of the model is right considering the leaks while the bricks are not joined or i need to put a grid under the wood... So i would be sure my model is right before to make the "real" stove. I will try to make a stronger fire, with more woods tomorow. Thanks in adavance Good day
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Post by satamax on Oct 15, 2018 17:16:05 GMT -8
Yep, try with a bigger fire, not too many sticks. And adding a makeshift door would help. As sealing the joints with mud too Well, i guess you're not near me, seeing how flat is it where you are!
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Post by salamandre on Oct 15, 2018 20:44:51 GMT -8
Hi,
thanks, i will try this. I am in south Haute-Vienne between Limoges and Perigueux...
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Post by satamax on Oct 15, 2018 23:40:00 GMT -8
Hi, thanks, i will try this. I am in south Haute-Vienne between Limoges and Perigueux... Well, near a place from where a part of my family comes. Belleix, near Bellac, Voutezac, Objat, in Corèze, but nearly next door. Some from Oradour. It's been a loong time since i've been there. I used to live further south, Bétaille, in the Lot, and Mauzac in Dordogne. Now in the alps!
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Post by peterberg on Oct 16, 2018 1:18:23 GMT -8
Salamandre, start with stacking the bricks with clay slip or clay sand between them. The batch box, and for that matter the J-tube, is very picky about leakage through walls. I can't make out what is in the back of the box, does that floor channel ends in a narrower vertical part, together called the cobra?
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Post by salamandre on Oct 16, 2018 13:16:47 GMT -8
thanks, i put some clay on the joints between the bricks and i made a bigger fire. It was a little long to start well but after there was a fire without smoke so i think it is good and i can pass to the next step. I have a cobra like explain in batchrocket.eu : the horizontale is 60x30 and the verticale is 35x35. There is 16 mm between the vertical piece and the port.
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Post by peterberg on Oct 17, 2018 0:36:30 GMT -8
So the cobra is to specifications, that's good. Avoid in all circumstances to stick a piece of fuel in the port, however small. This will disrupt the double vortex and causes the thing to smoke.
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Post by salamandre on Oct 20, 2018 5:34:21 GMT -8
Hi, i uploaded some new pictures: www.dropbox.com/sh/nxdp3wnbr2fd3te/AAAHbxcRHZ3Ryqg29eXWJxbla?dl=0I look at the installation of the stove in the house. Obviously few questions call me and of course i planned to build it tomororw... - The barrel arrives at 60 cm (23 inch) from a large oak beam and 50 cm (19 pouces) of the bottom of the chimney. Do you think it is good ? - I want to make a bypass at the level of the connection barrel / bench (in reality under the barrel, made by rax earth bricks), bypasse made by a métal piece powered by a métal rod through the bench in cob. Have you some advice to make something impervious while it moves ? Thanks good day
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Post by satamax on Oct 20, 2018 10:38:31 GMT -8
Salamandre, the norm in france, is, any piece of wood more than 18cm from a piece of heated steel from the chimney is considered fine.
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Post by salamandre on Oct 20, 2018 11:00:37 GMT -8
ok i prefer to be sure since somebody say the barrel can be very hot... thanks satamax i can sleep peacefully
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Post by salamandre on Oct 22, 2018 11:52:08 GMT -8
Hi,
after making the box respecting the specification as much as possible, max 3mm of gap except the longer to allow to put 50 cm logs.
I am making the part under the barrel in adobe (raw earth brick), a half decagone.
www.dropbox.com/sh/nxdp3wnbr2fd3te/AAAHbxcRHZ3Ryqg29eXWJxbla?dl=0
If I understood correctly what I read, in this part of this stove it is necessary that the passage of the smoke is at least twice as large as the section of the riser. In my case, it is a 150mm, so the section is 17 670mm2 . In the decagone I left blank a passage of 150mm wide, so the height must at least 236 mm. Am I right ? And if anyone has a remark, an advice when seeing the pictures, it is with great pleasure
I am sorry if I ask questions that seem simple, but after several months to read about the rocket and the batch box, it is necessary to clarify some "details". Espacially when it comes his first batch box... It is fabulous to be able a very good stove thanks people sharing their experience. I hop to be able to help other people after, by this forum or more near. I am trying to "convert" my neighbours or my friends to the rocket...
Thanks
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Post by peterberg on Oct 22, 2018 13:05:21 GMT -8
A low and wide opening is better than a high and narrow one and in general the wider the better. This has to do with the gases coming mostly from above and are forced to go around a 90º corner. A funnel-like shape would be the best. See also some older information about the subject and how to calculate it. donkey32.proboards.com/thread/337/helpful-hintA very successful heater is the one described here: Scroll down the page to post number 7, this explanation came out quite nice.
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Post by salamandre on Oct 22, 2018 13:24:07 GMT -8
Ok, i will try to change the opening, may a steel linte if the bricks are not enough wide.... When you are talking about a funnel-like shape, that means, i gradually fill the bottom around the riser (between the adobe and the riser in my case) in the aim to make a "toboggan" for the smokeuntil the opening ? It is better to fill with insulating material or massive material (the riser is made with insulatin bricks) ?
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Post by peterberg on Oct 23, 2018 1:04:32 GMT -8
salamandre, What you say is making a funnel down to the exit and go through the 90º bend after that? That's the other way around, the 90º bend should be twice as wide in my opinion. What I meant is down, getting wider and once the gases are through that bend restrict to the system size again.
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Post by drooster on Oct 23, 2018 12:20:13 GMT -8
There is a great description of a smooth bell-to-'bench' transition in that Permies Mag-Rocket writeup but I don't have a quick link ... I may try ... Credit to F Styles at Permies, this diagram shows a smooth 'ramp" cast at the base of the barrel ; (I'm sure there's a photo too, but I missed it.)
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