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Post by esbjornaneer on Nov 25, 2017 1:19:01 GMT -8
The oven back wall is not thigh and maybe the fume lateral exits are a little too small, but it is the idea to have an hot oven sole Hi Doc, Not sure if you are meaning thick or high with regards to back wall? |
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Post by independentenergy on Nov 29, 2017 15:41:38 GMT -8
perhaps the problem has already been addressed.
There may be the problem of ash being introduced by the riser in the oven.
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Post by rakettimuurari on Nov 29, 2017 23:34:16 GMT -8
perhaps the problem has already been addressed. There may be the problem of ash being introduced by the riser in the oven. This is true, although it is more like a compulsory feature... This year I burn spruce, which produces even more ash so the issue is noticeable indeed. However, in cooking it does not matter as oven is only used after the fire (and airflow) has ceased. When baking bread however, I usually clean the oven with ash vacuum-cleaner before the fire in order to maximize oven's heat absorbing capability (ash acting as insulate). With other cooking I just sweep the floor with moist rag. Any ideas about how to catch the fly ash? |
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Post by satamax on Nov 30, 2017 0:09:03 GMT -8
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Post by independentenergy on Nov 30, 2017 0:21:26 GMT -8
Rakettimuurari, I also thought of these solutions.
He is thinking of a barrier to block the ash particles, which are heavy, and by inertia they should crash and settle down.
just like the ramp at the base of the riser in the batch box system.
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Post by independentenergy on Nov 30, 2017 0:22:34 GMT -8
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Post by satamax on Nov 30, 2017 4:46:51 GMT -8
Cyclonic heat riser?  |
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Post by Orange on Nov 30, 2017 6:52:26 GMT -8
titanium filter! ? ! ?  |
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Post by rakettimuurari on Dec 2, 2017 0:07:28 GMT -8
titanium filter! ? ! ? Developing to promising direction... I'll be on watch  |
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Post by rakettimuurari on Dec 2, 2017 1:57:55 GMT -8
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Post by esbjornaneer on Dec 4, 2017 4:36:44 GMT -8
Hello Antti,
I had a thought drop in last night relating to the oven you have...
I have been checking my chimney temps more during my burns the last few days and found that they go down rapidly at the end of the flaming part of the burn. I assume that the chimney still draws a similar volume of air through the fire box and oven at this point, compared with the height of the flames and also during the coaling phase. So if my assumption is right it seems that a lot of cooler air is pulled through the oven during the coaling phase which is transferring heat originally captured in the oven and move it into the bell.
... so if there was a by-pass/valve that could let the gasses go through the oven until the end of the flames, and then direct the gasses straight into the bell while the coals are burning out, the oven temps should stay up. Does this make sense? I have not tried it and am not sure how it would be possible to make it. A metal flap would die quite quickly at the end of the heat riser. A brick/split would be tricky to operate from the outside. So my thoughts go to a piece of ceramic glass, but again how to make the design to operate it?
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Post by rakettimuurari on Dec 8, 2017 0:23:57 GMT -8
Hello Antti, I had a thought drop in last night relating to the oven you have... I have been checking my chimney temps more during my burns the last few days and found that they go down rapidly at the end of the flaming part of the burn. I assume that the chimney still draws a similar volume of air through the fire box and oven at this point, compared with the height of the flames and also during the coaling phase. So if my assumption is right it seems that a lot of cooler air is pulled through the oven during the coaling phase which is transferring heat originally captured in the oven and move it into the bell. ... so if there was a by-pass/valve that could let the gasses go through the oven until the end of the flames, and then direct the gasses straight into the bell while the coals are burning out, the oven temps should stay up. Does this make sense? I have not tried it and am not sure how it would be possible to make it. A metal flap would die quite quickly at the end of the heat riser. A brick/split would be tricky to operate from the outside. So my thoughts go to a piece of ceramic glass, but again how to make the design to operate it? Holla Esbjorn, Your thought drop sounds reasonable to me too. I have my first thermometer in the middle of the oven exhaust and I can confirm the same. At climax phase of good full batch burn the thermometer goes all the way tho 400'C (usually 320-370), it will be some 225'C when flames disappear, 175'C when air inlets are closed and 150'C when I close the chimney damper. I think your idea would be of some remedy but lie u write, the implementation is really hard. I have been digging little more around traditional Russian/Finnish baking ovens and there could be something to utilize too. Normally the fire is burned directly in those and after suitable amount of burning wood the embers are swiped (in bread baking scenario) already in the beginning of the coaling phase through the "ember hatch" (located on oven floor) into the separate ember chamber below the oven while still in full glow. Ember Hatch is then immediately closed and so is the damper on the main gas channel/ chimney, effectively fully stopping the gas flow through the oven. Meanwhile the embers will coal all the way in their separate chamber below the oven, which has adjustable air inlet in its main door and a small 3-4 cm separate smoke duct directly to chimney, bypassing the damper. Thus the embers will still add on heat of the mass without the airflow cooling the oven itself. I think this implementation could be also tried in my kind of design with the actual firebox. All what is needed would be a couple of cm diameter hole from the ash box (below the actual firebox) to the lower bell + closable ash hatch in the bottom of the firebox. When the flames disappear, the embers are dropped into the ash box, the separate smoke duct is opened there and all air inlets except the ash box door inlet and ash hatch are closed. I will be probably trying this later. More immediate modification will be a specifically cut baking stone slap of 2-3 cm. I a case of bread baking it will be inserted vertically in the oven before the fire, effectively making a full wall between the back of the oven and the exhaust slot to eliminate the short cut of the gas stream. A system CSA sized slot is cut in it, in the floor level in order to bring the exhaust to meet the oven floor before its exit. When starting to bake, this standing and preheated stone slap is gently lowered on the oven floor to receive bread directly on it. This mod I expect to try in few weeks. |
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Post by esbjornaneer on Dec 8, 2017 5:50:57 GMT -8
Hola, eller Hej (I am Swedish though living in Spain with an English partner:)), I am not sure of you came across this thread donkey32.proboards.com/thread/2362/building-stove-doors-dampers-hardware in the video Matt is talking about how he makes a by-pass valve. I found it after posting the last message here. It is just about dreaming up a design that makes it possible to use it... Best of luck with you 'fixes'! Every time I have build something I have learnt I should have done it differently. :/ |
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Post by rakettimuurari on Dec 21, 2017 14:18:27 GMT -8
can you compare effects of damper vs closing the air inlet? for the oven, you might need some metal or chamotte plate directly above the riser as the baking surface, should get higher temps. Here u go Orange: |
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Post by Orange on Dec 22, 2017 2:57:22 GMT -8
thanks for the illustration. Bell does the job. If you're a pro and want 5-10% more heat, play with damper  |
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