[Stoves] Up-date

[Harry Ha]

Dear Gus,
I like to see your video, but I can't find the link. Can you send it to me?
Regards,
Harry

From: crispinpigott at outlook.com
To: invfalcones53 at yahoo.com; psanders at ilstu.edu; harryha at sympatico.ca; ameripham at click1.net; peter.schild.mittelamerika at gmail.com; solarbobky at yahoo.com; art.donnelly at seachar.org; jonnygms at gmail.com; christa-roth at foodandfuel.info; biochar at yahoogroups.com; rongretlarson at comcast.net; tmiles at trmiles.com; stoves at lists.bioenergylists.org
Subject: RE: Up-date
Date: Tue, 27 May 2014 11:22:25 -0400

Dear Gus Many thanks for bring this product to my attention by video.  I will provide some comments because there are a couple of design issues that you can easily address. When the flame is first started in the stove (the canister is put into place) it can be seen that the flames emerging from the gasifier are ‘lazy’ and seeking oxygen. It is therefore a ‘diffusion flame’, short of air and the gases cannot burn to completion because there is no air supplied to them at the point where they exit the lower chamber through the ‘concentrator disk’.  The gas stream is only burning on the outside. Not good. There is a ring with secondary air holes in it above the gas entrance however they are so far from the flame they are unable to penetrate the gas stream (at all) resulting, even far into the burn, in a flame that is running underneath the plancha still looking for air. The air is there, but not mixed with the gases.  All the time they running under the plate, they are cooling off, making PM and CO. Not good.  Good clean burning does not come from flames running under the plate – it comes from burning the gases to completion in a low excess air environment.  This diffusion flame problem is very common in simple gasifiers because not enough attention has been paid to getting the produced gas burned to completion before the heat is applied to the working surface. In short, a flame running alongside a pot or under a plancha is a no-no. It has not finished burning yet but it is prematurely being asked to perform work. The flame can only be burned really well, to completion, if there is no metal or ceramic object in contact with it. That is best accomplished over as short as distance as possible. If you look at the flames coming out of an LPG stove they are small, short and intense. The reason is the gas is well-mixed with air in the right proportion, even though all the mixing is taking place outside the gas head. There are no ‘normal’ gas stoves with long, lazy flames reaching into the air 5 or 10 inches trying to find oxygen. They would fail the CO benchmarks if they did. Many of the elements of your system are really good, however the critical issue of the final burner needs to be addressed. I suggest that you replace the removable concentrator disk, just as an experiment, with two things: 1.       Put the concentrator disk inside the fuel chamber down perhaps 20 or 25mm so the function of homogenising the gas is performed.2.       Put a large central disk held in position by 2 or three metal bars where the concentrator disk currently sits. Make it about 30 mm smaller in diameter than the secondary air entrance cylinder. This will create a 15mm wide gap between the disk and the se4condary air holes forcing the gases out to the edge where the secondary air enters. The disk should be below the secondary air holes.  The idea is to get the gases to mix well with secondary air at the entrance holes ‘by force’. There is draft available from the chimney so the air should be pulled in well. The flames cannot be seen if the top is opened as that breaks the draft, so perhaps make a spy-hole in the top surface to see what the flames look like. Cover it with a piece of glass so you can get your eye close to the hole. Wear glasses. The result should be a number of inward-pointing flames surrounding each of the streams of incoming secondary air, all flames pushing towards the centre just above the central disk. This should create a number of much smaller and more intense flames. If you have the number of holes right, and the size right, and the shape right, there will be complete combustion without high excess air (something that can only be tested with a combustion analyser).  The flamelets, we can call them, should be fairly low to the central disk, then rise centrally towards the pot or plancha, then turn outwards radially. It will have the effect of heating the centre of the plancha most, but not excessively on one spot as an LPG burner head would do. The pot is probably far too close for the flame to burn well – raise it up without creating a channel for additional air to enter the combustion area. If you can get this structure to work, it will go a long way towards assisting others to make better burners. It is important to homogenise the gas so one side does not burn better than another – hence the use of a concentrator disk, but also it is important to get the secondary air into the gases as they burn.  Paul Anderson is recommending the use of a concentrator disk. Paul Olivier is recommending the use of a ring of flamelets (his are vertical). I am suggesting that both are needed if you want to get the flame length under control and to eliminate the problem of diffusion flames running under a large cold surface. Outcome: If it is working (you should be able to see the ring of inward pointing flamelets) the pot should heat water faster, and when you open the pot hole cover plate (a little to peek inside) you should never see any long, lazy flames passing underneath the plancha. The temperature of the plancha should rise more rapidly and the whole system should run hotter for the same burn rate. If this is the result, you can reduce the primary air supply a little and extend the burn because the system efficiency will have increased. Please let me know if you are able to get this result. It might be invisible to the user, but will result in better performance. Nice work.Crispin  From: Inversiones Falcon [mailto:invfalcones53 at yahoo.com] 
Sent: Tuesday, May 27, 2014 10:05 AM
To: Paul Anderson; Harry Ha; Thong - Haiti EmailUser Ameripham; Peter Schild - El Salvador; Bob Fairchild; art.donnelly at seachar.org; Jon Anderson; CHRISTA ROTH; Biochar Yahoo Group; Crispin Pemberton-Pigott; Ronal W. Larson; Tom Miles; Discussion of Biomass Cooking Stoves
Subject: Re: Up-date Dear Paul I have been working on our project, but until now I found the way to send you a good video, we can adjust any TLUD to all our frames (even desing new model for street vendors) I will like to tried to make an oven but at this moment I`m short of budget fot something like this, pleas send comments on this video Best Regar Gus 		 	   		  
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