Interesting alternative to sierra wood stove: wood gazifier

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Interesting alternative to sierra wood stove: wood gazifier

New postby James on Fri 20 Jul 2007 10:02

Looking on the net, I found this:

http://www.youtube.com/watch?v=pyofhLYY ... ed&search=
:doubleup:

http://www.woodgas-stove.com/


Sold arround 50$ so not very expensive. It seems to work pretty well, better than the sierra models, I am getting one for tests, will report how it compares to a sierra design later....
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Re: Interesting alternative to sierra wood stove: wood gazif

New postby boaty on Fri 20 Jul 2007 11:23

Great find!

They've got some other videos on YouTube as well - these four demonstrate gasification of various bits and bobs in drinks-cans (and the stove JM found re-appears in part 4)

http://www.youtube.com/watch?v=OYA-Er2zmbE
http://www.youtube.com/watch?v=i5lUVYy37TY
http://www.youtube.com/watch?v=akwI_zs1QDU
http://www.youtube.com/watch?v=FBmk8MNAuvQ

Gonna do this for the kids if it ever stops raining...
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Re: Interesting alternative to sierra wood stove: wood gazif

New postby James on Fri 20 Jul 2007 16:28

yep got news hat UK is under heavy rain.
Here is sunny, warm, and much too dry.
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby Jimbo on Fri 20 Jul 2007 18:15

I think I must be missing something..
Yep I use old cake tins to heat up cloth to make charcloth and burn off gas that comes out of hole on top. I've even experimented with new and old fashioned ways of making charcoal. I'm sort of guessing that these stoves recirculate gases from incomplete combustion of wood.
With a properly made can stove, though, with insulated chamber and good directed air flow, you are going to get pretty well complete combustion - no fans required.
Interestingly enough, before the middle of the last century, they were using boiler contractions to heat wood, in order to use wood gas to run vehicles.
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby James on Sat 21 Jul 2007 08:02

The amount of heat produced is probably what you are missing. I never could get any simple box do as well as these furnaces. it also depends of what you burn... ;-)
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby tuxdaddy on Sat 21 Jul 2007 16:08

Hey Jimbo,

I sent you a PM on this ..
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby Jimbo on Sun 22 Jul 2007 01:54

A lot of differences we see will be due to different conditions and wetness of wood. Whether we see differences or not, a good understanding is worthwhile because of advantages to us, and advantages in third world countries where fuel is not easy to get. If a person can develop a better stove, then people somewhere will benefit.

There is no denying the advantages of forced air. Here I can make an open framework of wood and have a terrific fire going in no time - if the wind is blowing hard. I've even made a narrowing funnel structure from rocks to concentrate the wind onto the fire - and all of us have waved hats etc, to fan a fire.
Because of damp wood here, I've found that it takes a lot of split wood to make such a fire provide a good bed of ashes in order that I then have a usable fire to cook, etc. Since I have many millions of tonnes of wood to use, that's no problem, but splitting it takes work and time.
With can stoves I found that the chimney effect with holes in bottom and heat causing air to rise and creating suction was sufficient to get things started. I still had problems with wet wood being added as incomplete burning slowed things down and created ashes which clogged air vents in base.
My quick and easy solution was to use two cans, one inside the other, so that a 1/2" gap was left all around. I then drilled four small holes through the bases of the cans and pop riveted. Next I drilled a whole bunch of larger holes through the bottoms of both cans. On arriving at the beach, I'd fill the gap around the side with sand, even wet sand, and light a fire in the can. The heat dries out any moisture in the sand fast and then the insulating effect on the sides keeps heat in the burning chamber. Things get really hot and so ashes produced are fine and don't clog.

What I found by that ten minutes' work solution was how much heat was being lost out of the sides of the burning container. It seems silly to use wet sand as an insulator - but it's amazing how fast that sand dries and then does provide insulation. Due to the insulated container and higher temps, wood was sufficiently dried to burn properly and ash falling to the base was fine and loose enough that air could pass easily and was super heated on its way upward.
With drier and better wood, I'd probably see advantages to forced air, but here convection is sufficient, or I'd be refilling the inside can every few minutes - or much less!
It's still a complicated affair. I found that the size of the holes in the base are critical, and are generally best to be smaller than what a person might think appropriate. I believe that this increases air velocity (as with a fan) and causes combustion to be much more intense in the base as air is super heated by hot ashes. Oxygen is used up in base and the rest of the hot air rising then helps to properly dry wood before starting it burning. So too much of a blast of air might be counter productive here. It's not the same situation as a forge with charcoal where more air = higher temps.
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby Stew on Sun 22 Jul 2007 12:08

Wow!

That's certainly interesting. It's kinda like how a trangia burner works but the air needs to be forced out to get the gas burning.

At that price I'm tempted to get one to play with.

Unless of course someone has plans on how to make one ourselves?
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby Stew on Sun 22 Jul 2007 12:32

Looking at this some more, I wanted to check if I have this right.

The diagram they give shows the basic airflow.

Image

but if I understand it right, the 2 stages are like this.

Stage 1 with the fan on slow 'feeds' the wood to make it burn hotter.

Image

There is some leakage of air coming out of the top holes but this is not a problem at this stage.

Stage 2, the fan is turned up to high. This pushes the air through fast, causing it to come out of the top holes and sucking the gases out of the main chamber.

Image

Do I have this right?
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby James on Sun 22 Jul 2007 14:21

I have the plans and made a few sierra like models last year(here attached). they are like your diagram, except there is no upper holes, only a limited amount of air passes in the high area, in order to push the flames toward the center. Right that the price is fair, the weight is a bit high to be really interesting for hiking. I'll see when I have one. it is possible that my current sierra copy can be modified to match this mode of burning.
Attachments
kscan_0019.jpeg
kscan_0020.jpeg
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby Stew on Sun 22 Jul 2007 15:18

I had forgotten that you had made your own Sierra mate!

I still haven't bought one as I was waiting to see if I could get one cheap on ebay.

Weight is not too much of a problem as a lot of my camping is done out of a car and I expect it would be lighter than a bottle of petrol + stove that I normally use anyway!

Looking at your threads on the Sierra, you have this pic of the air flow.

Image

Now, being the cretin that I am, I need a little help truly understanding what's happening. Is the air all gettting heated first? I can' see how that would be moving gases from the wood around!

Oh, and the first diagram I posted before was from the stove site. I added the red lines in an attempt to understand better.
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby James on Sun 22 Jul 2007 19:13

Yep, the sierra has air preheating, which allows it to burn almost everything once hot, including wet wood. But then it is not a wood gazefier stove, it is just a very efficient air pulsing stove (or a small portable forge :D ). However, I suppose that by making a few holes, it may fall in the same kind of working. I still have a steel sheet proto left, so i'll be able to play.

I doubt actually that there is much air in the bottom, it is possible also that they made semi-closed windows that would draw the air while it goes up to the higher exhaust, thus creating a rotative movement between the fire pit and the walls... I really do not now, these matters are complex, and unless I can see it...

If you really want one, mate, I'll probably have an extra one, and transport to UK may not be too silly from here, I'll give a price when it is here.

Sure Jim, that it looks like a good and economic way to do cooking in third word countries, so the initiative is, by example more interesting than that of a sierra stove. If it can help save some forests instead of turning them to charcoal, it cannot be bad.
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An easy to make wood gas stove without a fan

New postby DavidEnoch on Mon 23 Jul 2007 15:55

Here is a link to the Garlington WoodGas Stove. It does not have a fan and looks easy to make. I have been meaning to make one. I have collected the materials needed.

http://www.garlington.biz/Ray/WoodGasStove/

David Enoch
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby Jimbo on Mon 23 Jul 2007 19:38

That link provides a great start, David, but essentially it's not much different to the way I do things. I often pack a can stove and light from the top. I'd figure it to be a partial gasification stove, since what I'm really counting on is hot ashes falling to base to get everything going fast. I'd do things that way when I want to set up and leave can stove to get going on its own without feeding wood in.
I even light regular fires that way as shown here:
http://www.oldjimbo.com/pics/fire/

This page might show a feasible gasification stove:
http://journeytoforever.org/teststove.html

I'm thinking that if the top from the inner can is kept, and the edges smoothed, then it's pop riveted to base so that it can turn and regulate air, then it might be a fast way of testing the idea. It's going to be difficult to play with hot stove without lots of pliers to hold it with, but it'll sure be interesting to see whether it works. If it works then there will be charcoal left, not just ashes.

I'm sure learning from this thread. The Imbert wood-gas attachment for motors doesn't work the way I'd imagined:
http://www.webpal.org/b_recovery/3_alternate_energy/woodgas/contents.htm

Here my problems dealing with wet wood are very much different, but it's great to know that there's lots more to burning wood than I'd ever have imagined. And the more one knows about the principles of burning, the further a person is likely to get with their designs.
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby Stew on Tue 24 Jul 2007 16:47

James wrote:Yep, the sierra has air preheating, which allows it to burn almost everything once hot, including wet wood. But then it is not a wood gazefier stove, it is just a very efficient air pulsing stove (or a small portable forge :D ). However, I suppose that by making a few holes, it may fall in the same kind of working. I still have a steel sheet proto left, so i'll be able to play.


Certainly worth a try. Looking at the picture you drew of the air flow, it looks like the flow may be going the wrong way if you add holes at the top.

James wrote:I doubt actually that there is much air in the bottom, it is possible also that they made semi-closed windows that would draw the air while it goes up to the higher exhaust, thus creating a rotative movement between the fire pit and the walls... I really do not now, these matters are complex, and unless I can see it...


Yes. We are just guessing from little information.

James wrote:If you really want one, mate, I'll probably have an extra one, and transport to UK may not be too silly from here, I'll give a price when it is here.


Sounds good. Let me know if the extra becomes spare! :thumb!: This has really got me interested.

DavidEnoch wrote:Here is a link to the Garlington WoodGas Stove. It does not have a fan and looks easy to make. I have been meaning to make one. I have collected the materials needed.

http://www.garlington.biz/Ray/WoodGasStove/

David Enoch


Well done David. More ideas to think on. Would love to have the time to spend trying different things.

Jimbo wrote:That link provides a great start, David, but essentially it's not much different to the way I do things. I often pack a can stove and light from the top. I'd figure it to be a partial gasification stove, since what I'm really counting on is hot ashes falling to base to get everything going fast. I'd do things that way when I want to set up and leave can stove to get going on its own without feeding wood in.
I even light regular fires that way as shown here:
http://www.oldjimbo.com/pics/fire/

This page might show a feasible gasification stove:
http://journeytoforever.org/teststove.html

I'm thinking that if the top from the inner can is kept, and the edges smoothed, then it's pop riveted to base so that it can turn and regulate air, then it might be a fast way of testing the idea. It's going to be difficult to play with hot stove without lots of pliers to hold it with, but it'll sure be interesting to see whether it works. If it works then there will be charcoal left, not just ashes.


Jimbo,

Going back to your '2 can with insulation stove', that's definitely one to try. I'm curious if you did any design alterations before coming to this set-up.

I have an idea to overcomplicate the design but wonder if it would improve it.

I think I should go do a drawing.....
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby Stew on Tue 24 Jul 2007 17:07

Ok,

So as per Jimbo's design, we have a large can with a smaller can riveted inside. There are holes through the base of both cans and an insulating material is packed in the gap between the two.

My wondering is if air channels could be made through the insulation to get gas from the bottom to the top.

Some rough 'fins' could be welded in place to the inner can before putting the two together. A cap on the top of each air channel could be welded on afterwards.

A truly air tight seal would not be achieved but I doubt it would make a big difference.

The red on the diagram is where the insulation is located and the black is the air channels.

Image

Looking side on, a hole drilled at the bottom and top of each channel to allow the airflow.

Image

I realise this isn't forced air so woldn't work the same, just wondering along.

I wonder if it would work better if the air channels had a hole under the base to suck air up from outside?
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How about using fiberglass insulation between the cans

New postby DavidEnoch on Tue 24 Jul 2007 17:46

I was thinking about Jimbo's design and wonder if fiberglass could be used instead of sand? Fiberglass is very heat tolerant and is even used to insulate kitchen stoves. It weighs so little as to be a non-factor and would eliminate the need to fill and empty sand from the stove.

Those cupped stamped sheet metal or aluminum tent stakes could be used to create the air channels for the gasification that Stew was asking about. Just glue them to the outside of the inner can with JB Weld (a high heat epoxy) to create a passage from top to bottom. Holes would need to be drilled in the bottom and top of the inner can in line with where the tent stakes would be glued in. Or, if you placed the stake channels inside the inner can instead of outside the inner can, no holes would have to be drilled at all and the insulation could be continuous around the inner can.

I have seen another can/wood stove that uses a battery powered aerator that is used to keep minnows alive in bucket while fishing. http://www.backpacking.net/makegear/falk-woodstove/

Here are are couple other interesting wood stoves: http://www.backpacking.net/makegear/smitycampstove/ , http://www.littlbug.com/

Fun things to think about and play with!

David Enoch
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby James on Tue 24 Jul 2007 18:28

welding insulation would work.
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby Jimbo on Tue 24 Jul 2007 19:04

Going back to your '2 can with insulation stove', that's definitely one to try. I'm curious if you did any design alterations before coming to this set-up.


Other than trying a raised grate on the inside can, no. It works well enough, and is certainly simple and fast to make if you have two appropriately sized cans. I was going to experiment with making a much taller setup to see how draft was affected, but I decided to work with rocks instead.
The trouble is that here, if it's wet enough to require a stove to get wood burning well, you also need a fire to warm and dry off, and a can stove with insulated sides is sort of counter productive. Luckily the rocks on local beaches are schistose, so rocks are flat sided. I built a base wall with small air vents, then used four huge flat slabs to make the chimney, and packed the corners to prevent air getting in. Basically the mother of insulated sided can stoves. That thing would burn anything, and ashes never caused problems due to complete burning. Once I had a pile of super hot ashes, I knocked down the side slabs and had an open fire that I could throw anything on and have it burn - and could even cook on the hot slabs. It was a lot of work finding big slabs, shaping them, and hauling, but waves couldn't move them much so they were handy for next time at fire site. It can be a tedious and smoky affair gradually building up a fire in wet times here, and that speeded things up when Lyssa wanted a big fire right away.
So - simple chimney effect for draft and keeping heat in burning chamber to dry wood, give more heat, and so more draft due to convection sucking in air through base. It would actually be too effective for most places, since with dry wood, you'd go through fuel too fast. One of my friends makes these from old logging truck brake drums, and he cuts out designs on sides:
Image
It works far better than it should, and mostly because of the heat built up in the steel promoting draft. Without the picturesque cutouts on the sides it'd work too well! The whole idea is that it works well enough to quickly dry big chunks and has enough upward draft and heat to make smoke go up rather than in a persons face every two minutes.

So basically, other than learning, my needs take me in a completely different direction from gasification, in that I pretty much only deal with really damp wood - but I have lots available. At this time of year when things are driest, I actually have to make less efficient can stoves which burn smoldering rotten wood. I have those fitted with coat hanger bails so that I can easily place them so that while I don't suffer from smoke, black and deer flies are kept away.

I'm sure that better insulation would improve a double can stove, but I'd be careful about anything which might produce toxic fumes. Those cans get pretty hot!
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby James on Tue 31 Jul 2007 19:41

Well, I have received the stove. It is a camp stove, not a hiking stove, but it is extremely well built to last. It works well, and thows less flames than a sierra, though all depends of the type of fuel used. I could cook everyday of my life on that, no trouble.

Image

I'll make a review of that soon.

BTW, I have spare for sale in trading.
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby Stew on Wed 01 Aug 2007 09:46

I know you're going to do a quick review but can you tell me how high it is and what it's diameter is as well please?
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby tuxdaddy on Wed 01 Aug 2007 11:56

If you don't mind me asking, whats the difference between a hiking and camping stove ?? :bah: :bah:
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby Stew on Wed 01 Aug 2007 12:30

tuxdaddy wrote:If you don't mind me asking, whats the difference between a hiking and camping stove ?? :bah: :bah:


I suspect it's big and heavy so a pain to carry if hiking.

Camping implies not having to carry it on your back.
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby James on Wed 01 Aug 2007 21:07

Yeah, I should have said camp stove. it is two pounds, not really lightweight.

Total Height: 6.5" (16.5 cm)
Total Diameter: 5" (12.7 cm)
Fire Pot Height: 4" (10.1cm)
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby Taky on Thu 02 Aug 2007 03:17

I started my how design ont he sierra, but to busy, to many progects...

still, if you want to experiment I've found much easier to work with exagonal folded prototypes, than curving and riveting...

extremelly interesting discussion, the fan is a pain, we should be able to work something with out it... even if i t means to blow trought a tube a bit to get the fire/draft strated
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby James on Thu 02 Aug 2007 07:57

Ha ha, now you get all my attention. Yop, anything without moving parts is a must. I'll have to go into can stoves like Jim does, but I do not eat things in cans ;)
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby Stew on Thu 02 Aug 2007 08:13

Biggest problem I'm finding is sourcing two cans of different sizes!! :rollin:
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby James on Fri 03 Aug 2007 08:07

Yep, I hate the taste of canned food, so I never get the cans...
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby Stew on Sat 04 Aug 2007 13:44

Aha!!

So I was browsing youtube and came across:

Rocket Stove Workshop

which is very similar in design to Jimbo's idea he put forward but with a side entry for refuelling.

A bit more searching and.....

http://rocketstoves.org/ (not to buy from but to look at a few pictures)

Larry Winiarski's Rocket Stove Principles
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Re: Interesting alternative to sierra wood stove: wood gazifier

New postby tuxdaddy on Sat 11 Aug 2007 03:18

You know ?? After checking out that youtube on rocket stoves it made me wonder about what could be used inn the wood stoves to lighten it up a bit(weight wise that is)...

How about using wood ash like in the rocket stove.. The way I'm thinking, you'd put a layer of sand in the bottom(wet or damp), then fill up with ash to the last half inch or so, and then maybe another layer of sand(damp again).. Once you get things hot in there it'd seel the ash in place ...

How's it sound to you all ??

:confused: Tux
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