|
|
Post by peterberg on Oct 23, 2019 0:59:43 GMT -8
Scott,
As I said before, 25% tolerance to the depth/width ratio of the port wouldn't be a problem at all. As I see it, depth in your case would be 10 mm more with a port width of 54 mm, so that's roughly 20%. Well within tolerances, I would say.
Please don't chamfer the sides of the port, there's a stiff chance it will destroy the proper working of the afterburner function.
As for the firebox dimensions: don't worry about it too much. If you are building a 6" batchrocket, take the width of the brick as the base figure (B) which would be 4.5", isn't it? With larger bricks, all dimensions will slightly increase the same percentage this way. You'll see that the width of the firebox will increase the same percentage as the height and depth, port will be slightly higher and wider, riser wider as well. A 6" chimney is already slightly larger than a 150 mm one, so this looks like a happy coincidence also.
To sum up: firebox width 2B, height 3B, depth 4B, port height 2.2B, port width 0.5B, riser 6" diameter or slightly more, according to my calculation it would be 6.2" diameter or square 6.2".
Incidentally, the Mallorca core build turned out to be smaller because of the smaller size of the bricks. I just adapted it to the brick dimensions. The drawings aren't the holy grail, the proportions are. So adjust to your convenience as long as the ratios are correct, within reason of course.
|
|
|
|
Post by scottiniowa on Oct 23, 2019 16:41:15 GMT -8
Very good Peter, and many thanks for your work/testing and designing. I will proceed with expected good results and with nothing being actually built on the latest as of yet, all is good to now carry on.
The cold is setting quick this year, so should be good to get this started fairly soon.
thanks again.
Scott
|
|
|
|
Post by scottiniowa on Oct 23, 2019 16:45:50 GMT -8
And yes, 4.5" is the base width for fulls and splits, with 2.5" and 1.25" for thickness widths.
|
|
|
|
Post by BenAlexanderT on Nov 6, 2019 12:01:36 GMT -8
I'm getting reading to cast a new dsr2 core and I was thinking of extending the firebox length within the 25% margin you're suggesting; but I read somewhere that when you extend the firebox, you essentially increase the wood load and by extension the air intake requirements. Is there a formula that I can use to calculate how much I should increase the primary air? For example, if I increase the length by 10%, should I also increase the primary air by 10%? Someone here, in the forum, with increased length of the firebox, had a problem with his stove and i saw someone suggesting increased primary air. P/S: How thick should the castslabs be? At the momment they are 50mm in my drawings. photos.app.goo.gl/1JJJTgQkNx1seLgX6 |
|
|
|
Post by independentenergy on Nov 11, 2019 19:37:06 GMT -8
if the open system has to work with a draft regulator on the cimney it would be possible to use a smaller diameter of the chimney compared to the diameter of the system, for example, a 180 system and a 150 chimney?
|
|
|
|
Post by peterberg on Nov 12, 2019 2:15:57 GMT -8
I'm getting reading to cast a new dsr2 core and I was thinking of extending the firebox length within the 25% margin you're suggesting; but I read somewhere that when you extend the firebox, you essentially increase the wood load and by extension the air intake requirements. Is there a formula that I can use to calculate how much I should increase the primary air? For example, if I increase the length by 10%, should I also increase the primary air by 10%? There might be formulas to tune the size of the air inlet, but I would be very surprised if there's a simple one. In order to really calculate something like this would require a lot of parameters such as the chimney draw in different circumstances, whether or not there are retrictions somewhere in the system, the moisture of the fuel, air tightness of the house or the lack of it to name just a few. Due to a lot of differences between materials, chimney size and quality, fuel etcetera it's practically not doable to have a simple formula. What I do myself is starting the fire, open the air inlet fully and leave door open just one finger thickness. As soon as the fire catches on, the chimney temperature will rise and the draw increases. At about 90 ºC I'll close the door a bit further to compensate for the stronger draw. Most of the time the chimney temperature will drop somewhat at this point and start to rise again soon after. When above 90 ºC again, I'll close the door fully and leave the heater running by itself until glowing phase is almost over. But then, this works for me, my heater and its circumstances. This doesn't mean it would work for you. How thick should the castslabs be? At the momment they are 50mm in my drawings. Using a proper bought refractory castable I'd regard 40 mm as about strong enough. One remark: don't lay the floor channel in a trench. You will need to cast the 45 degree sides in the firebox anyway. So it would be very practical to just lay the floor channel on the floor and use two fill pieces left and right. |
|
|
|
Post by peterberg on Nov 12, 2019 2:20:53 GMT -8
if the open system has to work with a draft regulator on the cimney it would be possible to use a smaller diameter of the chimney compared to the diameter of the system, for example, a 180 system and a 150 chimney? No it won't. The crux here is the time of startup. Using a smaller chimney than system size you'll run into problems during that phase. I used a draft regulator for the development stage, yes. But that doesn't mean it couldn't be run without it. My own red bell never had a draft regulator, although it might be easier to run it using one. |
|
|
|
Post by esbjornaneer on Nov 13, 2019 0:33:48 GMT -8
if the open system has to work with a draft regulator on the cimney it would be possible to use a smaller diameter of the chimney compared to the diameter of the system, for example, a 180 system and a 150 chimney? No it won't. The crux here is the time of startup. Using a smaller chimney than system size you'll run into problems during that phase. I used a draft regulator for the development stage, yes. But that doesn't mean it couldn't be run without it. My own red bell never had a draft regulator, although it might be easier to run it using one. Correct me if I am wrong (or delete this post). I have a memory of the draft regulator being used in a 150mm chimney when you were working on the 120 or 125mm CSA core. |
|
|
|
Post by peterberg on Nov 13, 2019 6:41:03 GMT -8
I have a memory of the draft regulator being used in a 150mm chimney when you were working on the 120 or 125mm CSA core. That's true, the DSR2 in my workshop. Reason for this: official tests in the EU call for a stable draft throughout the burn of 12 Pascal +- 2. Originally I was doing this development with the possibility of commercial use as background idea. Not that it did bear fruit but hey, that's life. |
|
|
|
Post by independentenergy on Nov 14, 2019 4:58:30 GMT -8
so in reality it is possible
|
|
|
|
Post by peterberg on Nov 14, 2019 6:26:54 GMT -8
so in reality it is possible In the sense of: the core could be run on a bigger chimney provided there's a draft limiter installed. Only necessary in high winds, it prevents the core to switch to thermal runaway. |
|
|
|
Post by independentenergy on Nov 14, 2019 16:39:58 GMT -8
ok i understood thanks
|
|
|
|
Post by scottiniowa on Nov 18, 2019 10:01:21 GMT -8
I'm getting reading to cast a new dsr2 core and I was thinking of extending the firebox length within the 25% margin you're suggesting; but I read somewhere that when you extend the firebox, you essentially increase the wood load and by extension the air intake requirements. Is there a formula that I can use to calculate how much I should increase the primary air? For example, if I increase the length by 10%, should I also increase the primary air by 10%? I must have missed something along the line. I thought the open system (for this version), was just that, completely open with NO door on the fire box, in fact no secondary air tube either? In my haste, perhaps I jumped to the conclusion that a lot of these things were not needed with this system? I did a dry stack and cut just a few brick to make the dry stack work well (fit together) I of course had the front face of the upper chamber closed off with glass, and all the other dimensions very closely followed. The burn went well. Then I read the above, with the question part about the "air intake" requirements.... and think, I must have really missed this part as all the drawings were shown with the brick layout in sketch up. And I did not see any of them "at the end" with primary or secondary air doors or adjustments. No harm done as I am still just in the dry stack level of making this work. While I am asking the questions, The "white portion" shown in sketch up, on the inside of the firebricks, is to be insulation? This is shown at three sides? and I assume this is pretty important to the whole stove? Just trying to get the final details of the stove correct. Thanks |
|
|
|
Post by peterberg on Nov 18, 2019 11:50:19 GMT -8
I must have missed something along the line. I thought the open system (for this version), was just that, completely open with NO door on the fire box, in fact no secondary air tube either? In my haste, perhaps I jumped to the conclusion that a lot of these things were not needed with this system? No mistake, you are on the right track. I did a dry stack and cut just a few brick to make the dry stack work well (fit together) and it went well. I of course had the front face of the upper chamber closed off with glass, and all the other dimensions very closely followed. The burn went well. Then I read the above, with the question part about the "air intake" requirements.... and think, I must have really missed this part as all the drawings were shown with the brick layout in sketch up. And I did not see any of them "at the end" with primary or secondary air doors or adjustments. No harm done as I am still just in the dry stack level of making this work. While I am asking the questions, The "white portion" shown in sketch up, on the inside of the firebricks, is to be insulation? This is shown at three sides? and I assume this is pretty important to the whole stove? Just trying to get the final details of the stove correct. Thanks In essence, I did the development of the DSR2 parallel in open and closed versions. The closed one obviously has doors, air intakes and a floor channel. It runs as reliable as the open version although its efficiency level is somewhat higher, only to be expected. That white three-sided portion in the drawing is 1" superwool but one could use insulating firebrick or split hard firebrick to achieve the same thing. To be honest, I never tested the thing without this riser liner so for the time being we need to stick to what is really tested. It pleases me to hear just a dry stacked core went well. Expect a proper sealed one to be even better, as long as the recipe (excuse the pun) is followed to the letter. |
|
|
|
Post by Karl L on Nov 21, 2019 1:19:21 GMT -8
Peter, do you think it would work to construct a 120-125mm core from 25mm thick insulating firebrick?
Or would 25mm not provide enough insulation?
(Clearly the riser would be thicker than 25mm -- more like 50mm)
|
|
