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Post by ronyon on Sept 5, 2019 20:03:39 GMT -8
Magnificent work as always Peter.
I especially like the air feeding door frame.
I was thinking I could use 1 5/8 inch steel studs and/or track to build the door frame.
I think it's (roughly) the right size, it's cheap and easy to find and work with, but it might be too thin skinned at 20 gauge, roughly 0.81mm.
What do you think?
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Post by Lucian on Sept 6, 2019 2:05:42 GMT -8
Thank you Orange for sharing this. One question though: the formula for port depth in this calculator is "port width x 0.8". Is this right? The table on batchrocket.eu shows a fixed value of 50mm for all system dimensions. I wonder if the port depth will influence the burn much. This has been on for debate some time ago. In a very early stage (of the batchrocket concept) I tried deeper ports and found adverse effects when the port was deeper than twice the width. Making it shallower than width meant nothing happened until it was below half of the width. So I concluded port depth should be close to width- say within a margin of 25%- in order to get the right proportions. As it happened, I used firebricks for those experimental builds of just over 50 mm (2"). The system size at the time was 150 mm or 6", and I arrived at the port's about 2" width by trying a number of different widths and heights. So in that configuration the port was as deep as it was wide. That said, in 2014 I built an 8" version where the port was slightly wider than deep and the thing performed admirably. So there is some tolerance in there. Does this answer your question? Yes, all clear, thank you very much. |
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Post by josephcrawley on Sept 13, 2019 9:46:21 GMT -8
Peter do you have an opinion on the door frame tubing scaling with the size of the stove. For example if the sketchup is scaled up to a 200mm this brings the frame tubing up to 81x54 which seems awfully large to me. Would it ok to keep it at 50x50?
thanks
Joseph
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Post by peterberg on Sept 17, 2019 11:09:44 GMT -8
Peter do you have an opinion on the door frame tubing scaling with the size of the stove. For example if the sketchup is scaled up to a 200mm this brings the frame tubing up to 81x54 which seems awfully large to me. Would it ok to keep it at 50x50? I'm afraid you need to scale the frame up together with the firebox. The 50x50 duct would look decidedly thin on such a large firebox and it would be too cramped to function as an air frame. |
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Post by Jura on Sept 21, 2019 11:55:43 GMT -8
First calculate the desired scale: 125/150 = 0.8333. Then select the whole core. Then hit 'S' for scale and start dragging one of the corners: the scale varies with the mouse movement. At this point you can enter the scale you want *numerically*, in this case type the digits: "0.8333". Then hit Enter and it applies that exact scale. I remember myself to have committed such mistake with scaling in sketchup. I haven't paid attention to a mere fact that scaling method changes not only the total size of the object but the size of the brick as well which in my case resulted in a lot of troubles and additional cutting. btw. Welcome back to everyone here after my long absence. I'm plodding through a 9 months backlog of posts |
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Post by smartliketruck on Sept 22, 2019 7:03:50 GMT -8
Where to add length to top box? I'd like to make the firebox longer and have the top box the same length as bottom, so where to add length to the top box, between riser stub and stumbling block, between stumbling block and second port or add on to the dead end?
Edited to add:
I've been scaling the drawings by using the tape measure tool, for instance if you want to scale based on riser size click on one corner in the riser and then click the next corner, type the number you want it to be, hit enter and sketchup will ask you if you want to resize the whole drawing.
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Post by peterberg on Sept 22, 2019 11:09:40 GMT -8
Where to add length to top box? Maybe you didn't have a look at the last drawings. The latest, hopefully final, drawings shows a top box with the same depth as the firebox. There are four drawings: start with page 21 and work your way through. Those four are: open system in cast slabs, open system in firebricks, open system in split firebricks with one inch CFB around it and closed system with doors, air inlets, the works. |
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Post by smartliketruck on Sept 22, 2019 11:39:11 GMT -8
Maybe you didn't have a look at the last drawings. The latest, hopefully final, drawings shows a top box with the same depth as the firebox.
Sorry, I was unclear, I'd like to extend the firebox longer than standard say by 15 to 20% and thus extend the top box to match.
Depth of only 11 3/8" for a 4" system calls for some pretty short pieces of fuel.
This would also be good to know for converting various system sizes to best utilize whatever size bricks you happen to have available.
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Post by peterberg on Sept 22, 2019 12:12:01 GMT -8
Sorry, I was unclear, I'd like to extend the firebox longer than standard say by 15 to 20% and thus extend the top box to match. Depth of only 11 3/8" for a 4" system calls for some pretty short pieces of fuel.
This would also be good to know for converting various system sizes to best utilize whatever size bricks you happen to have available. Ahhh... you would like to extend the firebox and a top box to match. What you need to do is simple: the exit port is a quarter of the depth from the front and the stumbling block is halfway, that's all. Just stretch the depth in SketchUp and it's done. Note: 25% extra depth is within reasonable tolerances. Not sure what would happen if you stretch it more than that. |
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kpl
New Member
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Post by kpl on Oct 4, 2019 2:43:59 GMT -8
Any idea, would it also work the other way? Shortening the top box would allow it to fit inside the circumference of a barrel, upper barrel would not need that cutout any more.
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Post by peterberg on Oct 5, 2019 0:04:05 GMT -8
Any idea, would it also work the other way? Shortening the top box would allow it to fit inside the circumference of a barrel, upper barrel would not need that cutout any more. Yes, it would work. In fact I did this earlier and results were quite good. The end port should be at the front of the top box in that case. Have a look at the start of this thread. Size of the end port as per the latest drawing of course. |
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Post by josephcrawley on Oct 14, 2019 16:03:36 GMT -8
Does the roof of the fitrbox need to insulative or could it be hard brick? I imagine this would slow the heating of the top box a bit.
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Post by peterberg on Oct 15, 2019 0:17:29 GMT -8
Does the roof of the fitrbox need to insulative or could it be hard brick? I imagine this would slow the heating of the top box a bit. It could be hard firebrick, no problem. In fact, in case one would need the top box as an oven it would be best to use refractory bricks or slabs throughout. That's what I did and it works for sure. |
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Post by esbjornaneer on Oct 17, 2019 8:08:26 GMT -8
Thank you for all the updates and drawings. Good on you!
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Post by scottiniowa on Oct 22, 2019 13:06:16 GMT -8
This has been on for debate some time ago. In a very early stage (of the batchrocket concept) I tried deeper ports and found adverse effects when the port was deeper than twice the width. Making it shallower than width meant nothing happened until it was below half of the width. So I concluded port depth should be close to width- say within a margin of 25%- in order to get the right proportions. As it happened, I used firebricks for those experimental builds of just over 50 mm (2"). The system size at the time was 150 mm or 6", and I arrived at the port's about 2" width by trying a number of different widths and heights. So in that configuration the port was as deep as it was wide. That said, in 2014 I built an 8" version where the port was slightly wider than deep and the thing performed admirably. So there is some tolerance in there. I have built a few stoves (RMH's) and they worked well, and I would like to build one more...I have a great deal of fulls and splits, but when comparing american to metric bricks, I find they are a bit different in some measurements So then go back through these pages, to see if the question has been ask, and I just missed it. So I will pose it here. Going over each of the sketch up drawings, I find a few differences in the measurements do to difference in the actual brick size. they are as such. (all based on the 6" sketch up drawings) for full bricks here, I end up with 215mm width vs 216 fire box so little difference height of 342 vs 324mm so wondering and 457 vs 432mm deep, so from what I can read this will be no problem? but on the port the % difference is a bit different with full, i'm at 63.5mm depth because of the full width vs 54mm on sketch up (I can cut back the edges to get to the depth required, which sometimes promotes a venturi effect) depending on cuts and front or back side these cuts. and I can make height 228mm to what ever is required with max of course the 342 and of course the width to exactly what is wanted. Lastly, it shows if with splits, the port depth of only 30mm, and mine would 31.75 because of split width in my area. And the drawings show the one with splits insulated but the fulls NOT insulated. I can do either... I am fairly sure I will go after the open design as it looks like a great fit for my all cement basement and its darn simple but proven working ability. if this is exactly called out and I have missed, I will gladly go to this given area to find. thank you in advance. |
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