Progress pictures ------- Puff back valve & modified bell. Any opinions whether this valve is sufficient or not? Will make adapter flange with desired
reduction hole.
Peter C
Hi Mike, Thanks for the specs. Tomorrow i am going to try to finalize my new dimensions. Thanks to you guys, there is a lot to choose from. At least now i can make somewhat of an educated decision.
Peter
Hi Gary, I appreciate all the information. At least when i fire this up next time, i will have much more of an understanding of what is happening. Great idea about leaving a lip. I will fab one & weld it to my reduction hole adapter plate.
Peter
Here Pete, This is the (MP series II gasifier) Im building. Im sure its hard to tell the geometry from a top shot. It usually looks 2D. But it has a 4" restrictor and from restrictor to jet tips is 4.5". My jets are sloped, so they need to be a little higher. The hearth is taperd from 12" at the top and 10" at the bottom. The restrictor openning is aligned with the bottom of the tapered hearth. The reduction bell is 4" tall and has an 8" openning at the bottom. Then there is a 10" reduction tube that is 4" deep. The grate fits inside this and is adjustable up and down.
Hi Peter, Iām glad you found something, I was almost at the end of the list. On that same note I took another look and I wonder how air tight your grate shaker handle is. It could be sucking in air and relative humidity.
The upper part of your bell is 2.5" high and is 2" below the nozzles for a semi total of 4ā5". Now add about .5" to bring you up to the C/L of the nozzle (the spec reference location). This gives you h= 5", the distance from your flange to the C/L of the nozzles. You propose to add another flange with a diam of 5" also and bolt them together. This satisfies the general dimensional relationship here. That seems a logical choice and one I would try.
Try temp plugs in 3 nozzles so the others will have greater velocity for deeper penetration into the combustion zone for higher temp. Note there are only odd numbers of nozzles in the chart.
Keep the lower part of bell and lower the grate as much as practical to give as large a char bed as possible.
Donāt use silicone here. Airtight wood stove rope gasket is needed, machining aside (not to detract from your machining), 1300 degrees F can do funny stuff to the flanges especially. Add centrifugal fan to the want list.
There are a lot of variations that work, this one will also I feel.
Good luck, Pepe
Matt, Your unit looks great. Very hard to get prospective on everything. Sure wish i could see it in person. I still have yet to physically see a gasser of any kind !! Does anyone know of a gasser in my area?
Thanks for the information
Peter
Peter, This creates a bigger glowing char pile that the gas passes through. The longer it takes the more complete the reactions to produce the combustible gases. In my unit this is the R + H value(10+") I had to design into the burner. Higher quality gas, I believe.
You can try it as is, itās a bit experimental at this point.
Pepe
Pepe, My grate shaker handle is a .250in rod in a .258in hole. The plate that it is going through is .375in. Is this too much leakage? If so, how do you seal up moving shafts? The dimension i ended up with is 4.00in from flange to nozzles. I was thinking 4.50in hole in my new flange. What diameter rope seal do you recommend? Should i make the sides on my grate higher & lower the grate?
Peter
Hi Guys
There WERE fossile coal mobile gasifiers developed before and during WWII. So it is possible. All Iāve been able to read on started up first with wood charcoal or burnt prepared coke.
Iāve seen the pictures and puzzled through some translating. But NO post WWII further developing that Iāve ever seen or read. I think because then liquid Dino fuels became so cheap and available. And the DYIāers like us were only interested in grow it in your own back yard wood fuels.
Chris Seymour has the old system pictures archived and Max gasman probably knows of the fossil coal fueler systems.
Regards
Steve Unruh
Hi guys,
Can anyone tell me how to make a tight seal on a moving shaft in a hot area? Such as shaker rods.
Thanks, Peter
Iāve heard of people using graphite powder between capped ends. Iāve never had that problem as our small unit doesnāt have a grate shakerā¦ just a threaded rod that holds the grate up there. Havenāt had any problems with air sucked through that threads.
I was thinking threads also. This way you can adjust the grate height also. Or just turn it back and forth to give it a little up and down motion.
Another way I have thought about would be to have a small pipe come off the gasifier and where it is cool enough use a part of a tire innertube to make a tight but flexible connection to a rod. This will allow it to move in and out without letting air in.
anthony
Arvid,
I have a grate suspended by chain. A .250 rod comes out the side linked to the grate. After re-measuring the clearance today, the hole is .250 the rod is .246. The plate that the rod goes through is .375. (all dimensions are in.) Wondering if this leak is insignificant.
Peter
Anthony,
In videos, i have seen operators reaching down, & shaking the screen with a handle. Apparently, the grate is hooked to a linkage that pierces the gasser.
Just wondering how this is commonly constructed.
Peter
Hi Peter, Iāve only done this once, hereās a picture of it ready to screw down.These parts are from a 3/4" or 1" gate valve (just had it for years). It has a bushing insert for sealing the shaft, hmmm thatās cool. The brass pipe is part of the valve also. I used both ends of the original shaft and added the length I needed to make the grate connection.
I added the packing around the shaft just under the cap just because. I ran the unit twice for an hr or so each time and experienced no pops, puffs or blow backs, but Iām not sure that makes it air tight.
Later I brazed the cap to the rod since the inside connection would rotate in the slot. Screw it airtight, Unscrew it, do your push pull, screw it airtight. You just need that inner connection to be able to rotate.
My GEK type has the rotating grate which I like a lot. It seals tight and did away with the push rod and the sled grate but I had the luxury of room to do it, but on the other hand my unit is approaching two stories! Also, I would buy new bushing inserts or if not available( and they werenāt for this one) a new gate valve. I ended up brazing the cap so I could screw it down airtight.
Maybe the .004" (.002") you have may be Ok, I donāt know.
Hope this helps. Pepe
Peter, I saw this setup somewhere, canāt remember where. It was for a turning grate also but it was simple and uses parts readily available. You fill the caps and the pipe and when they are screwed together it makes everything tight in there. Not sure how this would work for sliding in and out though.
Don M
Hi Don, I think this will work given how a tube of silicone hardens in the tube and doesnāt seem to shrink at all. Sure is a lot simpler and quicker than what I did. It may take a while for the RTV to set up in the pipe, I suspect.
I may put together a small prototype just to try the fit. I have a couple of caps already drilled out from a previous trial. Iāll get back on the resultsāmaybe some days yetāgarden is busy.
Pepe
Guys, I just had to try this. I greased the inside of the tube before I filled it. Filling is easier if you put the plug with rod in one end and extend the spout to the bottom of the tube( piece of small tubing over spout) between the rod and wall and pull it back as the tube fills. Weāll see what it looks like. Iām going to wait 2-3 days before I try the pull test. Pepe
