Giorgio and Tone,
Dave & Brian, @d100f, seem to have good success with a tungsten carbide nozzle.
I think silicon carbide would also work well because if is used for foundry crucibles.
Rindert
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Hello Giorgio , love your build , i have not had a chance yet to test out a downdraft , so its hard to 100% give advice on the longevity of downfacing nozzles , but if i were a gambling man i would have a bet on a flute type down facing made of very thick walled steal pipe , and the Hexoloy carbide lasting a good long time .
My one and only Hexoloy is still inside my reactor and still working after 3 years although its now spring and so i wont use it that often now during the hot season here in Australia .
Here is the link to the same type that i and a few others have now bought , the postage may work out a bit pricey , but when you weigh it up over the years its still running then its a very cheap part of the gasifier .
Dave
https://www.ebay.com/itm/303217180639?hash=item469926ffdf:g:YXYAAOxyVLNS8m55
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hello rindert , hello dave and brian,
thanks for the information, looks interesting…
quality is always the cheapest way…
my first nozzles were only for the first tries, here in the italian outback it is alway difficult to get pieces and first i take what i can find on my backyard scrap place…
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I’m one of the people Dave turned on to those hexaloy nozzles Giorgio. I don’t run my gasifer every day but so far there has been no noticable damage to those tubes. The just slide into a piece of pipe. I could melt a pipe nozzle in a couple of runs. For anyone else interested. I have bought four of those nozzles now and the seller shipped them immediately with no issues.
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How do you guys attach them? Glue it with refractory?
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Mine just slide into a pipe coupling. I think inch and a half. All my pictures are on a different computer. I look for one later.
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Since it has a decent ID I might try to use one for a downdraft charcoal gasifier for a car.
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Well, they are good to just have around for experimenting with if nothing else. I think shipping was only 50 cents more for the three I purchased together than when I order just one.
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Silicon carbide is used for many things. It is also called carborundum. It is used as an abrasive. Many grinding wheels are made from it. I think you will find pieces of it in most scrap places.
Rindert
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How would you go about making some kind of nozzle out of those grinding wheels Rindert? Like you say, they would be pretty easy to find if push came to shove.
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Hi Tom,
I think I would try to use stone mason’s methods and tools. Stone mason’s hand point chisel. Maybe i could start with a cold chisel and reshape it in my forge so that it would function like a real hand point chisel. Old style star drill. Perhaps a hammer drill. I have a grinding wheel dresser (not diamond) that I got at HF, so I would study how it works. I spent a few hours cutting flag stone last spring. I learned a little bit. I would try to build on that. Of course youtube would have a ton of stuff.
Rindert
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Here’s another partial answer to how to work silicone carbide. I was able to use a cheap Chinese diamond hole saw, for tile, to cut the center out of this cup grinding wheel. I will use this as the restriction for a small engine gasifier based on Joni’s plans.
Rindert
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I actually have a set of those cutters. My wife was looking for something and saw them on sale, wanted to know if I wanted them. I never say no.
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I have a Starret brand of those kinds of hole saws. They work good on steel as well. I got them for large diameter holes because I didn’t want jagged teeth catching thin barrel steel and bucking the drill out of my hands.
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Do you think you could splice a tyre cold like you would to fix a conveyor belt?
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I don’t really know Wallace. I’d like to know a lot more about it though. I know contact cement holds well to splice leather but not sure about rubber. I have use two part butyl caulk and once that set up you can hardly cut it.
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here we modyfied a bit our first gasifier (summer 2020)…the primary air tube was situated before inside of the hopper - advantage: easily to make modifications of nozzle hight…
BUT the heat conduction to the outer shell not exists and heat convection is only with the pipe, and seems not enough, the nozzle soffers a bit…
so, actually , because the right nozzle hight has been found, i fixed a new stainless steel nozzle(how in my other gasifiers) direct with the outer shell for better heat convection, how in my other gasifiers…
the startup-lighting vessel is also now outside and works well…
last days we cut a lot of firewood with the bandsaw, 5 to 6 hours dayly without interruption, after this time is needed filter cleaning.
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