Tom, my ring of fire gasifier did folow the lmbert dimension chart, the air jets still had a velocity of about 25m/s. I just decided to try and cross the air curtain incinerator with a gasifier. It worked fine, no question there, but l think its not worth the effort. Standard 7 nozzle gasifier worked just as well.
Drue has made a modified FEMA. Only upgrade is the reaction zone is somewhat more fixed thain at stratified FEMA design.
Drue, in a lmbert, the idea behind nozzles is they blast sir in at high speed, createing a turbolent enviroment for the tars to mix with air and burn.
You might get by by not useing air jets with your long reaction zone, but unfortunaly you will not get by with no restriction on such a small engine. In a way, you now have a 6" restriction. I had a 4" restriction on my 136hp engine, just for comparison of how narroe you need to go.
Ading a restriction will make a gasifier a whole lot better.
Uuummmm!! Some times you get into a discussion and a little voice in your head says, âjust shut up and listen because others know much better than you (me)â". The little voice has spoken but I donât know enough to listen
Yep Kristijan, your nozzles did follow the Imbert dimensions and your ring of fire was just auxiliary air to burn tar that may have escaped between the nozzles. ( that is my interpretation of what happened) Drue, with no nozzles is working more like a WK design. He really doesnât design for a particularly high velocity air coming out of the nozzles. There fore he isnât looking to penetrate the charcoal column to or near to the center. It just comes out of the nozzle and bends down and in the long distance to the restriction it works its way through the entire column which as it goes down is diminishing in diameter as it approaches the restriction. Drueâs ring of fire does like Mr. Wayneâs, it penetrates the column but mostly, bends, blends in and oxidizes on its way down.
Yes Drue has made a modified FEMA. And yes adding the ring of fire has âfixedâ the oxidation zone. I believe the moving oxidation zone was the reason for tar not burning in the FEMA.
I am all for a ârestrictionâ but first lets see if this will work HIS way with out it. Iâve said it three times already, but one more time, Drue is confusing himself/and us, by NOT knowing how hard he is pulling on the gasifier with the shop vac. My impression he is pulling very hard ( or as we say âoverpullingâ) Overpull will burn tars. He has a valve to cut down the amount of vacuum. I am not sure he IS cutting the vacuum pulling on the grate/reduction zone/ring of fire. Maybe my thinking is incorrect but; If you have 2 pieces of 4in dia pipe connected by a piece of 1in dia pipe and you pull 50 in. H2O on the end of one 4 in. pipe, you will NOT get 50 in. H2O at the other end of the other 4 in dia pipe ( if the other end is open. if closed another story). I believe that is what he is doing with the ball valve he thinks is restricting his vacuum. He could have 50 in. H20 at the shop vac. Then it goes into a 1 in dia pipe and then back out to about a 2 in. dia pipe. ( 2in.- 1in.- 2in.) At the end of the second 2 in. pipe he will NOT get 50 in of vacuum but may 30 or 40in. H20. That would still be over pulling his gasifier, thus getting a blue tar free flame. For a good running gasifier I believe we need to run at 10 to 15 in. H2O vacuum. To get that in the 2in. pipe at the gasifier, the ball valve would have to drop the vacuum in the 1 in. pipe to about 20 to 25 in. H20.
All of these figures are just stuff off the top of my head but the point I am trying to make is, when he turned the ball valve towards OFF I did not see the flame diminish, did you?
I did see him run the snow blower, which in my thinking is WAY underpulling his gasifier and yet he didnât gum the valves up. So as of yet, I donât think we can say his design is a failure or needs modification. I donât know how he is getting away with out a restriction but heck, one guy on here stopped putting a GRATE in his design-- I have a problem understand how he is getting away with that. TomC
Thanks Max; I tried to find it on the internet. 2 use copies in the US for $244.68. In the UK 1 used copy for 288 something ( I think pounds) A little steep for my blood. I believe they are only in German.
Alte Technik mit Zukunfit: Die Entwicklung des Imbert Generator
Hang on to your copy-- it must be a collectors item. TomC
Thanks for all the suggestions? I put a restrictor plate in the bottom of my burn tube on that ledge. Cut it down from 6" to 2" was able to start it with an air mattress pump. Little snow blower pulls on it good now. Iâm gonna run it for a few hours then look at the valves and carb
Drue,
I think a restriction sized for the engine is a fundamental gasifier thing. Sometime after running for a good long time, let the gasifier cool down and unload the fuel and char a level at a time to see what your char bed looks like. Kind of a post-mortem thing. Several inches of char is what you want with no unburned fuel pellets in that area.
And a person would be able to get a rough idea of dimensioning from the iImbert tables. There is also some good info on calculations to arrive at all the info based on engine flow. An internet search should provide that mathematical basis. @gasman had just provided that info a while ago.
Iâm no authority, but itâs good to start from a rational basis, and then make minor adjustments. It appears you have lucked out exceptionally well on a first attempt. I agree with earlier analysis that you have basically built an improved FEMA, and that it seems likely that tar is being burnt from overpulling, or condensed in your very cold and long cooler.
Any which way, itâs working decently, excellent start, now as they say, the 75% - learning, refining.
Drue, Just thinking about your flare being hard to extinguish. Your shop vac may not be over- pulling the gasifier, but it might be sucking in some outside air at the lid of the shop vac, mixing with your seemingly very clean gas, making a nice burnable blend.
Well, if it has been running for 2 hours, the gas must be pretty good. Tar, if bad, will stick your valves open when the engine cools off. I know Matt Ryder will run some gasoline at shut down to clean the engine. If you want to check for tar, Iwould think 2 hours is enough. Someone with more experience might disagree.
After shutting down the gasifier, just let the snow blower sit until tomorrow morning or so. Then turn it over by hand, turning the fly wheel. If it is tared up you will reach a point where the fly wheel will lock up. Doing this by hand will prevent the momentum on the flywheel which can bend a push rod. If it turns over a few times go ahead with the starter or rope pull. I think you are going to be ok. TomC