Koen, if you can figure out the multi-nozzle puzzle, that will be awesome. I’m surprised they don’t have weighted check-valves for this kind of thing. I just did a quick Google search, but found nothing…
I start my build on Saturday. Going with a propane tank… Updraft.
Troy
We have a “how you call it if you are the first one to publish” situation 
You may very well be the first… We would call that “an inventor” 
I tried a different Google search, and this page is a bit more interesting:
https://www.google.com/search?q=weighted+check+valves&rlz=1C1CHFX_enUS436US436&es_sm=93&source=lnms&tbm=isch&sa=X&ei=mzJjU7q2BJfboATQuoLgCw&ved=0CAkQ_AUoAg&biw=1536&bih=764#q=air+nozzle+check+valves&tbm=isch
Also, it’s easier for me to buy long TIG cups (welding cups) for the nozzles… Very similar to ceramic electrical fuzes, and rated for 3000 C+ … Might be harder to find than fuses, though…
https://www.google.com/search?q=long+tig+cup&rlz=1C1CHFX_enUS436US436&es_sm=93&tbm=isch&tbo=u&source=univ&sa=X&ei=PzNjU-GRPMv_oQTC5IGYDQ&ved=0CDcQsAQ&biw=1536&bih=764
Troy
These long tig cups look great…
Will try to find some here…
I wonder how brittle those TIG cups are? Maybe we’d need to build up some sort of protection around them to keep them from getting broken off.
I’ve thought about casting the nozzles into a refractive cement base to lock them in place and also overcome the softness of the refractive that wears away slowly. No time til fall to play with my toys though.
Best regards, David Baillie
Brian,
My buddy is a welder/fabricator that use a TIG torch every day… | suggested we use a terraccota clay pot that comes already with a 1-inch center hole on the bottom. The top of the tig cup would be flush – or sticking slightly above flush – with a couple mm if spacing in between. The idea was to protect the tig cup from a 55lb barrel of charcoal crashing down. Also, the concave structure of the vitrified clay pot would reflect and insulate the heat… much like firebrick. The heat would get reflected back into the combustion/reduction zone to help with efficiency, and to keep the combustion zone at a minimum of 1500 C.
But after this plane, he said all that wasn’t needed. a bag of char crashing down would do nothing… He’s said they’re super tough… In fact, he’s dropped his welding gun – tip and all – and landed on the cups, and they didn’t break. He said they do break from a 4 foot fall on concrete, but only rarely. Needless to say, we’re stoked about using these, and will report back with data. We anticipate a lot of testing, reporting, tweaking, and testing again…
At this point, I will not use the pot. I might eventually get to that point in the future, but i want to start with the simplest system, and only enhance components of the system when it aids in total thermal integration, and made from readily-available, off-the-shelf parts. Ultimately, I need to find resonance with efficiency, affordability, availability, simplicity, and utility. I really like the direction Koen is taking his journey, and along with Gary, are two very influential and inspiring people.
We’re going to start with some open-source plans of a very simple, efficient, and available… Affordability is relative, but we think under $700, and that’s if you pay retail, and didn’t cherry pick deals on Craigslist 
Google SketchUp drawing coming…
Troy
Here is the concept so far…
– Standard 100 lb. propane tank
– Tank inverted with welded legs
– 10 inches above ground level
– Standard stainless pipe nipple with TIG welding cup nozzle
– Light from bottom with torch
– 6 inch PVC drain with stainless mesh filter
– Also serves as a re-fueling port, just pull out
– Shop vac wet/dry 2.5 HP motor with media filters
– Venturi burner
– Onan 4.0Kw BFA 1800 RPM generator
Hi Troy,
Welcome to the site and thanks for the check valve reference. I have an imbert style gasifier sized for running a 30 + HP engine ( line D, 90 M3 per hour ideally for 45HP. I used 70% factor or 31.5 HP) Right now I only have an 8 HP engine to play with (working on an 18 HP), so I’m producing way too much gas. Dan Cox suggested running both the flare and engine off the same line. He noted and I agreed that I was under pulling the system. I’ve thought about installing a tee in the line and using the flare to generate steam from my large pressure cooker. This would be valve fed into the hearth zone of my gasifier for experimenting. Gas for the engine would come from the tee also. That’s where my need for check valves comes in. For safety, I felt I needed a check-valve in each feed. Very interesting looking site.
Pepe
Troy looking at your Sketchup for a charcoal unit you should probably run your shopvac off of a “t” to the line running to the engine and valve it closed once you get a good flare. Some people do do the inline blower but a shopvac is too leaky for that. Some raw wood gassers use the inline blower method to flare off a portion of the gas to keep the gasifier hot as they run a small engine but you won’t have that problem with charcoal. Trust me you want to introduce as few routes for air leaks as possible as they will drive you mad running them down.
David Baillie
Hi Troy, Really like the sketch up. “A picture is worth a thousand words” A few comments on your plan. What about taking a 3” pipe nipple, cut it in half and weld this to the bottom of your tank. (make sure you also have a hole cut through the tank) A 3” cap will then be screwed onto this nipple. This 3” cap will have a 1.25” hole drilled in it and a 1” pipe coupler welded in that hole. A 1” pipe about 3” long (the nozzle) is screwed into that coupling so that when the cap is screwed in place the nozzle will extend into the interior of the propane tank. I find that welding two bars on the cap makes it easier to screw and unscrew.
The nozzle pictured is designed to go on the side of the tank, therefore the nozzle is longer than what you need. In my hand is a stainless steel sleeve that helps protect the steel nozzle from oxidation.
With this setup, you will be able to empty the tank from time to time to dump accumulated ash.
I am concerned with the use of the shop vac to pull suction. That is WAY more pull than your engine will require. It may even pull some charcoal from your gas generator and over heat the oxidation zone. How about throttling down the amount of vacuum somehow. Be careful about sucking charcoal gas into any container. It is explosive if mixed with some oxygen.
Looks like you are well on your way to getting a charcoal gasifier up and running.
Until later, Gary in PA
Gary, I miss you in Argos 2014 already.
Yes Doug ,
I miss Gary also and the event is over a week away.
Troy, I really like the sketch up! However, I see an issue. I would not use pvc ANYWHERE that isn’t below 100 degrees. If your gasifier runs low on charcoal, it will melt the pvc. Use a 4 inch iron pipe nipple with an iron cap. Gary is absolutely right about welding a pipe on a cap to use as a handle. It works, believe me. And just use hard iron pipe as your pipe to the filter. Why not? I believe a heavy duty dimmer switch would throttle the vacuum down some. I will post some pics of my setup very soon! It is a wood downdraft with a couple of twists.
Gary,
When I build my personal system, not only will I do something very similar to what you’ve illustrated in the images above, but I’d also like to address some variable nozzle flow characteristics, exhaust control, steam control, ash clean-out, etc. Ideally, that whole bottom bung assembly will comprise of multiple sub-components.
For this round – and in the spirit of trying to make a viable system with no welding required – we are going to test our hypothesis that a simple (not ideal) solution can be reached with off-the-shelf parts. We’re hoping that the nozzle assembly in the attached photo will be far enough away from the propane tank wall to avoid the high temps at and above the nozzle tip. Hopefully, we can use it as a lighting port too (I’m worried about this one, but we’ll see), and a removable/changeable platform for different sized nozzles.
I welcome all constructive criticism, and I’m sure the “vision” will need many rounds of improvement before I can say “It works!” Let’s keep the communication flowing, as I am learning so much from you, Koen, and many others on DOW.
Regards,
Troy
Note: Ideally, all these nipples would be stainless, but they weren’t in stock, so we’re going to test with the 3 metals you see in the pic (stainless, black pipe, and brass). the order is already in for all stainless pieces.
That looks like a great nozzle Troy. For starting with the long nozzle I was using wd40 with the long thin straw. Turn the fan on squirt up for a few seconds then the torch… acts like BBQ fluid…
Have fun, David
Thanks David!
That’s a great tip about WD40 and the long straw… Will try it.
Troy
Here is a little update to the “OpenFire” charcoal gasifier concept…
Definitely not very pretty But… No welding required, and all with off-the-shelf parts. Hopefully it works!
Jonathan, we’re going to use ABS instead of PVC… Once I get this “open source” concept done, tested, modified, and working… I will switch to a purpose-built unit for myself… Stainless steel, fully fabricated, etc.
The challenge here is how to do this with zero welding… It’s difficult! but i think this may work with some hi-temp RTC silicone.
As for the dimmer switch, we’re going to try a variac, or maybe just a plain old light dimmer… need to look into that a bit more.
Send your pics up when you get a chance.
Thanks!
A word of warning on using a dimmer-switch for your shop-vac: Some motors don’t like spinning slower than normal at all (less speed = less internal cooling fan speed) and some are very picky about their slowing methods (might run very inefficiently causing more heat production). I ran into one (or both) of these problems with my small electric forge-blower (salvaged from furnace). Once I used a ball-valve to control my draft (instead of the dimmer-switch) and just left the blower at full-speed, it ran much cooler.
I’d also be a bit concerned about how air-tight the shop-vac is. I know many people use them for start-up but then remove/isolate the vac from the system to avoid leaks, either Carbon Monoxide out, or more likely, air into the gas stream making a explosive mixture before one wants it to be.
Not to be nit-pick, but if you want to have a “zero-welding” system, you should probably find a leg/stabilizing system that isn’t welded on. You could probably get away with a few L-brackets and some sort of retaining rings/bands. I don’t have time right now but I should be able to sketch up a diagram of what I’m talking about later, if needed.
