time
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Post by time on Aug 8, 2015 2:44:49 GMT -8
Just curious if it is known what will happen to performance if i makes longer batch box?
i/e the 180mm batch box calculator calls for a batch box that is 259 wide, 389 high, 518 Deep batch box. what effects should i expect from a 259x389x788 batch box?
Time.
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Post by satamax on Aug 8, 2015 4:41:37 GMT -8
Time, you will have to experiment.
There's one thing i can tell you, long fireboxes are not practical stuffing wood in the end for startup in front of the port, cleaning etc are not that easy. Especialy with a long firebox, as you're proposing.
Plus, i'm not absolutely sure, but i think Peter said once, max 30% increase in firebox lenght. Tho i might be completely wrong.
The limits are practicality, and overfueling.
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time
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Post by time on Aug 14, 2015 22:27:20 GMT -8
Decided against it.
Started on an all metal build today using peters dimensions.
3mm pressed steel bell, 10mm pressed steel burn/batch box with S-Portal, 180mm 15mm steel riser wrapped in 50mm superwool blanket.
But i have 2 options for the flue. 2.5m of 8in or 2.5m of 10in
My understanding is that the 10in will be better, is that the general consensus?
Time.
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Post by satamax on Aug 14, 2015 23:35:56 GMT -8
Metal is doomed!
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time
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Post by time on Aug 15, 2015 0:01:56 GMT -8
yeah...but what size flue.
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Post by alanloy on Aug 16, 2015 14:05:31 GMT -8
Sorry Time don't know about flue size.
To help explain Satamax's shout here is a quote from Peterberg (2012)
No numbers either. But there's more to tell about whether or not a rocket stove will eat mild steel. Simply put, it's a combination of high temps, low CO and high O2 levels. We all do know by now, a rocket stove is able to generate very low CO levels. Subjected to high temps (1830 F and more) the oxygen is extracting carbon out of the steel, reducing it to rust. A great deal of spalling will occur, visible by dull grey flakes on top of the steel surface. Leave one of the conditions out and nothing disastrous will happen.
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Post by satamax on Aug 16, 2015 21:39:01 GMT -8
Thanks alan.
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time
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Post by time on Aug 28, 2015 0:41:23 GMT -8
Thank you all for your help. Ended up with a 6in system but a 7.5in size batch box (to fit a large side glass door). Seems to work beautifully well. smokes for 3-5minutes on startup form cold then burns very hot and clean there after.
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time
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Post by time on Sept 12, 2015 2:33:37 GMT -8
Some pics of the completed burnt in All metal batch box rocket. One batch of hardwood burns for about 3 hours. Great Draft with 3m Flue. Keeps a small court yard very warm and a nice flickering visual.
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time
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Post by time on Sept 27, 2015 0:55:04 GMT -8
HI,
So i have been using the rocket for some time now and it is performing well. However, i'm finding i get quite a lot of creosote build up in the batch box.
any thoughts on how to stop this?
Time.
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Post by satamax on Sept 27, 2015 3:29:25 GMT -8
Not enough primary air? Too slow a burn? Not enough draft? Not enough insulation on the firebox?
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time
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Post by time on Sept 27, 2015 14:52:51 GMT -8
Well, the air calculations seem to add up so do the draft numbers. but there is no insulation in the firebox at all.
hmm.
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Post by shilo on Sept 30, 2015 10:35:43 GMT -8
add the insulation and you can say goodbay to the mettal
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time
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Post by time on Oct 1, 2015 15:54:32 GMT -8
Solved, Longer hotel burns was all that was needed. no more half loads.
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time
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Post by time on Jan 25, 2016 15:06:47 GMT -8
A Quick Update.
This Little fire is just a wonderful performer.
I have noticed a few things others might find useful
1. It must be lit from close to the primary air for fastest smoke free condition (15minutes) 2. filling the batch box 80% achieves hottest flame and best burn time 3. Chet style portal is starting to deform from heat but is functioning extremely well and certainly acts as intended 4. The riser is 1200mm 10mm wall hydraulic pipe, it has suffered spalling for 800mm of it's length, which hot spots from 100mm to 400mm particularly affected 5. Stainless steel rack that i use to seperate the ash/small coal from the burning wood, melts and spalls away after 30 hours. 6. Opening the side door to refill the batch box once the batch has burned 40-50% leaves sufficient draft to make sure no smoke exists the box and is still hot enough to ensure no smoke leaves due to new added wood. 7. the higher density the wood the smaller the pieces must be for full combustion. i.e. 600kg/m3 i can get away with 10-15cm cross section, but the 1200kg/m3 i have most access to must be 5-10cm cross section to burn completely without smoke. larger pieces can only be added once there is a VERY significant coal bed.
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