I’m going to turn my attention back to the grate and remove the solid fence. This will be replaced with a taller heavy screen fence. This comes after reading Jim Mason’s GEK 5.0 revelations. Thanks Jim and team for an amazing “turn” of events. I figured I’d get a similar longer residence, higher fuel density if I had a larger volume of char similar to the grate basket shown here.
I just refound this pic that shows a cast in place grate basket circa 1970. The article is in the History category titled “Early woodgas from Australia”, post 14. Love the post numbering system. Go to Forum, on the upper left side of the screen click on All categories, then click on History scroll to “Early woodgas from Australia” post 14. You can enlarge the picture there for a better view of the “grate basket”.
My basket will take up most of the “H” dimension of 4". Probably 3 1/2" as shown by the cross sectioned grate.
Update- The diameter is 13 1/2". I used a 3" wall. The original wall was 2" so this increased the volume from 286 cubic inches to 429 cubic inches or 50%.
The new grate basket wall will be made from this heavy screen. Since my grate is 13 1/2" I can use a small properly emptied propane tank to heat form the new grate basket.
Hey Pepe,
I like the idea. I have an abnormally long reduction tube and I am experiencing almost no char to speak of after a good run. My grate seems to breath good too with no shaking. I think the char in place helps because my temps leaving the gasifier into my drop box are only around 350 F (temp taken externally on pipe)and my temps in the hearth are 2000 +. I think you will find that your char held in place will give you more gas and less char for cleanout… Just a guess. I can’t wait to see it go! Gordon
Hi Gordon,
I was experiencing quite a bit of over spill of charcoal into the base, that’s why the original 2" solid wall. Carbon that doesn’t make it to carbon monoxide. I’m thinking this is a sure plus. I’m getting anxious for a firing, too. I’ve got several more fixes though and I have to go at them uninterrupted to do the best job. Gordon, how is your temp probe mounted and where in the hearth area. I have a lighting port I thought I could use.
Pepe
Hi Pepe,
I just slide it in the lighting port. Luckily my port is almost a straight shot into my hot spot. I haven’t mounted my thermocouple permanent yet so maybe someone on the site can give a tutorial on the best way. Good to get that job done while it’s apart.
Gordon
Hi Guys and Gals,
I continue on from post 361 (aren’t the post numbers great), the grate basket case. This screen is not welded together so when you cut it short the pieces are loose in the weave. Yup, weld all the cut edges to keep the screen intact. I spent over a half hour on the first strip. Shown is my first completed strip and the edge it was cut from. I’ll scavenge the the ragged edge with a cutting disk for links to fill in walls. This screen is from a sand and gravel sifting machine. It is 3/8" squares.
That’s all the play time I had today. It was time consuming doing the cleaning, but the welding went pretty quickly. Hopefully, I’ll be able to finish this tomorrow.
Pepe
Hi All,
Got into the shop early this morning and finished the grate basket. I lined up and clamped one of the basket side pieces to the propane tank form. Note angle iron “legs”. This was quite a stable platform. Then I heated a section until it wrapped around with just hand pressure. I started at the back edge and worked forward always keeping the flame pointed on the entire heated portion. If you go the other way, you are continually backing up to reheat the spot you moved away from wasting time and gas. Continue working around the full length. I have a 3+ minute real time vid of bending screen section. I’ll post it soon. It’s a MOV file and I’ve never used youtube editor, so it’s bound to be slow, but it will get posted.
Pepe
Update-video as promised:
Start the next wall section. When you get near the end you can cut it for length. Too long, cut more. Too short, fill it with weld. Add lengths of 1/4" round stock to fill in any gaps in screen.
Install grate basket in char base. Update- The diameter is 13 1/2". I used a 3" wall. The original wall was 2" so this increased the char volume of the “basket” from 286 cubic inches to 429 cubic inches or 50%. That’s good, but what I think is significant is the surface area exposed to penetration by the gas. The solid wall had no flow through. The basket wall has 127 square inches, 85 square inches (the area of the solid wall) of which is now available for flow through. I’m convinced that will make a positive difference on the reduction side.
Hello Gasifier Enthusiasts,
Today I finished my upgrades on my char base. I made this tool to manually rotate my grate to clear it and any spill over between the basket and the char base wall. I cut a 3/4" section off a deep well socket and welded it to a cutout I made in a piece of 1’2" steel pipe. This is much easier than the vise grips I had clamped to the rod.
I ran into an ex QA team member and his friend at Lowe’s this week. Had a nice conversation about alt energy and gasification, They alerted me to the stone wool insulation shown here. It says it’s good to 2150 degrees F. A little pricey and a lot of insulation, but it sure looks like a gasifier candidate. I’m going to spring for a package and I’ll show you what it looks like unwrapped. More tech info at roxul.com
I used it too Bill and Pepe, both for fire tube housing and gasket material. 1& 1/4 inches around the fire tube housing allows me to hold my hand on the outer housing and rustoleum paint does not burn off. Works good. Wish it came in smaller packages though.
I used the rock wool on my 94 Ram and it seems to be good stuff.
Chris was down this week and we went out for a drive in it and at about 30 min in the drive I had him to touch the fire tube housing to show the insulating ability . The temp was very close to ambient.
As more time passes the temps will go higher but has always been cool enough for a quick touch
Good morning All,
Thanks for all your comments. I’ll be insulating my present burner shell, maybe the char base and preheat shroud and preheated air delivery tubes. Some of it I plan to wrap in sheet metal removed from water heaters. That sheet metal is painted on the outside and already circular for ease of fitting around tanks. Picking away at any performance enhancements I can. I know this stuff is pricey, but without having to pay shipping and handling it’s competitive and as Bill says I’ll have enough for my next 5-10 gasifiers. Optimist!
Don, I’m curious where did you use it as a gasket material? Thanks.
Pepe
“For the gaskets I pulverized a chunk of mineral wool in a 5 gallon pail with a high speed electric drill with a wire whip and used a continuous 1/4 inch layer as a gasket with RTV above and below as a binder. It kind of mushed together and formed a high temp gasket that seems to seal very good under high heat.”
Hi Don,
Thanks for the repost, I do remember reading it. Now that I’ve read about the temp resistance of the rock and mineral wools it seems like a good way to go. I thought I might combine it with the high temp latex caulk that Tom C. uses.
Regards,
Pepe
