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Post by Vortex on Nov 24, 2014 2:41:29 GMT -8
Vortex, so good to get some confirmation! I assume you must have a PvdB Batch in addition to your vortex stove, or did you put a similar secondary air tube in the vortex cook stove? This is in my Vortex stove, I just copied as near as I could what you've done there but in my stove. The effect is just as you described it even though there's no port behind it. I'll definitely be experimenting with this more. |
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Post by captainchaoss on Nov 24, 2014 5:37:43 GMT -8
As a Noob, I've been studying all the threads, videos, and books. Like many, I've had to learn which designs were good, and which were "crapulent" ( love that term, thanks Eric & Paul )
To further add to my dilemma of what size to build, configuration, cast or stacked, etc. now you guys are constantly innovating new ports and doors ! Different mass options - bells, benches, barrels, cob lasagna ( thanks Satamax ) till I think I'm FURTHER from starting my heater, rather than closer. That's ok, I'd rather continue to learn so I can build as good a fit for our home as possible. I'm beginning to think a batch hooked up to a bench may be more suitable, so I'm trying hard to understand all the trains of thought you guys are throwing out.
I understand the secondary air supply needs to be heated before introduction to the fuel stream, and it's taking approximately 10 minutes for it to reach a stable burn. Wouldn't it be better to keep the channel at the top of the burn chamber where the hottest gases are ? Sorry if this was already discussed and I missed it. I usually can't study this stuff till late at night after the kids are asleep. I fall asleep reading at times, and things don't always register.
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Post by matthewwalker on Nov 24, 2014 9:30:44 GMT -8
Capt.C, I don't know about the air channel on top. Maybe? My gut tells me it's hotter in the coal bed, but I don't know. It's easy to set it on the floor, that's for sure.
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morticcio
Full Member
"The problem with internet quotes is that you can't always depend on their accuracy" - Aristotle
Posts: 371
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Post by morticcio on Nov 24, 2014 10:58:19 GMT -8
Matt,
Could you confirm the dimensions for v5 please.
I have a 1m length of 50.8mm OD stainless exhaust pipe I could use to try one here. Thickness is 2mm.
Thanks
Andy
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Post by matthewwalker on Nov 24, 2014 11:04:56 GMT -8
No problem Andy.
Dimensions I.D.:
Horizontal is 2.25"w x 1.25"h
Vertical is 2" dia. round
Inlet csa is 2.8"sq., outlet is, uh, well, the slot is 2.25"sq. but the top is open, so available outlet csa is the total of the tubing, 3.14"sq.
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Post by DCish on Nov 25, 2014 8:29:25 GMT -8
Vortex, I'd love to see a pic of your implementation. I wonder if the best location in your stove might be along the top of the burn chamber right before or at the point where the smoke exits the firebox. This would put it injecting secondary air at a point where it is dedicated solely to re-burn, much like many modern box stoves do. (Apologies if this should be on the vortex stove thread)
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Post by grizbach on Nov 25, 2014 9:23:52 GMT -8
Vortex, I'd love to see a pic of your implementation. I wonder if the best location in your stove might be along the top of the burn chamber right before or at the point where the smoke exits the firebox. This would put it injecting secondary air at a point where it is dedicated solely to re-burn, much like many modern box stoves do. (Apologies if this should be on the vortex stove thread) DC, I believe this to be true. I am not having any secondary air enter the lower port on the try-outs I am making for Matt. Also, there will be a higher vacuum at the top of the port as opposed to the bottom. Terry |
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Post by matthewwalker on Nov 25, 2014 12:01:40 GMT -8
Peter, your sizing recommendations were right on. v5 is very nice, stable and predictable. The O2 is at the same level as before so I'm inclined to think the secundary supply is still too large. Maybe you could stuff the top and the bottom holes with superwool? When that doesn't yield the right effect then it's time to restrict the inlet side of things slightly in order to see what's happening. Well, I've run a full battery of tests with the top half of the slot and the top closed. I'm sorry to say, this is terrible. I have also played a bit with obstructing the inlet side. While there are times it can handle a bit less air, I am of the mind that the 2.8"sq. is about the right number. It leaves headroom for large fuel loads, but runs stable and predictable throughout the cycle. I believe that achieving lower excess air numbers won't be attained by reducing air at this point. As you know Peter, after a point that has the opposite effect, and I believe we have hit that point. The trick now will be to control the gas flow to supply just enough gas to keep things relatively low, without overfueling. A delicate matter. I'm quite happy with v5, I think it's pretty much there to my mind. It is slow to warm up, and perhaps there is some operator element there, like closing the secondary and opening primary until the stove is warm. I've been playing with that a bit, but would like to settle on a configuration that requires only one setting adjustment from start to cruise. Overall though, in normal use, just feeding three splits every hour to two hours, this thing runs great. I was working outside most of the day these last two days and the chimney was clear the whole time, without me trying very hard to achieve good results. Just burning like a normal stove, put wood in, close the door, walk away. It's a very useable configuration. I'm looking forward to trying what you are working on Terry, I'm fairly confident that I'm 90% there with v5, but we won't know until we try some other ideas. |
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morticcio
Full Member
"The problem with internet quotes is that you can't always depend on their accuracy" - Aristotle
Posts: 371
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Post by morticcio on Nov 25, 2014 17:15:17 GMT -8
Thanks for the update and your time and effort Matt.
Just a thought, would a sleeve which rotates to cover/uncover the vertical slot help to fine tune/adjust the amount of secondary air be of any use? This could be operated by a rod with 3 settings say 100%, 60% & 30%. Similar to manual chokes we used to have on cars back in the day. Or would closing the feed at the door have the same effect?
Did you install a P Channel in this when you converted it? If so, is it removed or just blanked off for these experiments?
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Post by matthewwalker on Nov 25, 2014 17:26:37 GMT -8
Andy, there is a standard P-channel in this one, and yes, it's blanked for these tests. At some point in the near future I'm going to go back to the standard configuration and live with it for another day or two and make sure I'm not way off in the weeds on this one. I'm digging it currently, and have been very warm with a small amount of wood, but it does have it's moments of frustration as well. If you try to shut it down before it's warm it's a bad time.
I do think that an adjustable thingy would be cool, and my neighbor speculated on that as well. The best idea we came up with was a split sleeve over the outside of this tube that you could rotate to adjust slit openings. It induces other differences though, so that makes it hard to use as a test device. I think the simplest is just to change them out. They are dead simple to make.
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Post by grizbach on Nov 25, 2014 18:40:35 GMT -8
Thanks for all the details Matt. It lets me fine tune things over here. I'll shoot for 2.8 then.
I'm squeezeing it in when I can. I'm guessing about 2 more days.
I adjust my intakes for each phase of burn.
Zero secondary and half damper for start up.
Open damper when wood catches.
open secondary when flames half fill port.
close secondary at coal phase.
I tend to use a very small amount of kindeling. I should increase this to quicken startup.(expecially with wet wood)
A "one setting for all" is a great goal to strive for but for cold start and coal phase, secondary air is hurting.
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Post by grizbach on Nov 25, 2014 20:25:42 GMT -8
Hey Matt,
It just occured to me, do you have the back of your tube about 1" away from the back wall?
The farther away your secondary intake is from the port, the less vacuum it will feel.
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Post by matthewwalker on Nov 25, 2014 20:43:58 GMT -8
Yeah Terry, I was thinking the same thing on the vacuum relationship with distance. I am guessing it's more like 2" at this stage. I would like to scoot it closer, but I cut it too short. If you leave the test pieces 19" long, I can try various configurations.
Good input on the air settings, thank you for that. I really appreciate all the input, from all of you. It helps immensely.
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Post by ivehadenough17 on Nov 27, 2014 7:52:38 GMT -8
Matt, I am a machinist by trade and would like to help with what you need made up.I have a good working relationship with a steel supplier, If it's standard size tube most of the time I am given drops for free. What I would require from you is a print of what You need.Hand drawn would be fine.You have helped me, I would like to reciprocate and help you if at all possible.
I am obviously new to this board, and I am still figuring it out. I just stumbled across this thread by accident. You can message me the print through this board or Youtube.
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Post by matthewwalker on Nov 27, 2014 9:33:07 GMT -8
Matt, I am a machinist by trade and would like to help with what you need made up.I have a good working relationship with a steel supplier, If it's standard size tube most of the time I am given drops for free. What I would require from you is a print of what You need.Hand drawn would be fine.You have helped me, I would like to reciprocate and help you if at all possible. I am obviously new to this board, and I am still figuring it out. I just stumbled across this thread by accident. You can message me the print through this board or Youtube. That's a very kind offer, I appreciate it and may take you up on that as we finalize things. Terry is sending some test designs, which will keep me busy for a bit. Once we move on to the next refinements I may send something your way. I'm glad you are posting, it's good to see you here! |
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