I don’t use the cyclone anymore. I switched from 1/4", crushed charcoal to bigger stuff, just as it comes out of my TLUD. 1/4" - 2", I guess. I did a little write-up at First gasifier project - #2 by r_wesseling
Rindert
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I always carried a small mirror on my lawn tractor to see the nozzle instead of looking at it without protection.
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Well- Ive seen other people use em. I would be reticent to use them with wood but on charcoal I should have no issues. This one was at the dump so the price was right
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Yes Im keen to drill out my lighting tube plug so I can cement in a circle of hi temp shott glass and be able to see my hearth under load
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A little update - I wanted to be testing this today-Thursday. But Im still waiting on a few things that are in the courier system.
The main jobs Ive knocked out is the hot side piping which was really enjoyable. You will see it all flanged up but not fitted yet as Im waiting for Hi temp silicone and stove door rope.
Ive riveted a biscuit-cookie tin to my bracket to house the electrics when they get added.
My PVC bits arrived and Im assembling the cold side.
Jobs to do before test run- lighting port, air inlet, burner nozzles, grate and shaker, insulate hearth. looks like that wont happen until after the weekend.
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Monday: Ive pulled it all apart. For the 34th time. Thankfully the entire build is rivnutted and only uses one size of bolt so the entire strip down takes about 3 minutes and one tool. A drill driver fitted with a 10mm socket.
I have just built the shaker grate and painted all the PVC pipes so that they dont look like PVC. That is really important. 
Earlier today I began wiring the pyrometers and the blower. I’ve run extra wire in the loom In case I want to run a grate shaker, hopper vibrator or cooling fan on the heat exchanger. Tomorrow morning Ill mix up some of my own DIY refractory cement made from crushed pumice, plaster and wood ash in equal parts by volume. That will get packed around the terrocotta flower pot reaction zone and will fill the upper half of the 9kg LPG tank. The lower half is the ash box.
Other jobs tomorrow are fit the ignition port and the air intake and burner nozzle.
After that- put it all back together again- wheel it outside and set fire to it.
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I think it’s finished. Im waiting on the fire cement to cure. It has 12 litres - 4 gallons of fire cement around the the reduction zone. a good 100mm thick of solid insulation. It will take 4 days or so to cure as its in a steel casing. Ive made my ignition port and air inlet and nozzle. Its 40mm pipe with 5 ceramic 12mm nozzles. Ive reassembled it with hi temp silicone on all the joins and pipe flanges. and run the wiring though.
Tomorrow - Ill make a barrel of charcoal!
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3 hours ago I fired up my gasifier for the first time. my charcoal is a bit chunky 30- 50mm. I only have a reactor core temp of 300C. no bridging, 500ml of condensate in my jar on the bottom of the cyclone already. Inside of fuel hopper wet with condensation. the condensate was black- now amber brown
It lit easily- It’s producing a small whisp of smoke that wont light after 3 hours. the view in the ignition port is bright orange. It’s only produced a teaspoon full of ash so far. the fan is a 3amp 12v squirrel cage fan. it sounds lazy and dull. I think I might need a second fan or a more powerful one. (battery showing 13.8v, terminals tight, wire is 1.5mm2)
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I needed to post a meme to cheer myself up! Ive spent all day watching my infrared thermometer tell me that my reactor is too cold- now its dark. So Im on EBay looking for more powerful fans- who here has had fan lethargy problems? I think that the finned radiator may be causing too much restriction, although- Each fin has 5x 6mm passages. That’s 11 fins x 28mm open area. that is 308mm passage volume, so not a lot of restriction.
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Congradulations on your first run. Even thugh not sucsessfull, its still a start.
I might sound a bit harsh but its all in best motive. Constructive critic.
You jumped in the water head first without checking if its deep enaugh. What l mean to say is you went all in and designed a brand new style gasifier, instead of going the usualy reconended path, start with simple, prooven concept and improve upon them. Wich is fine! Once in a while someone does “invent” a new style, but unfortunaly 99% of people do not and end up doing it the old, prooven way.
We here are all eager to help each other and give out as much tips, tricks and experiances as we can so that the person in need of help dont get headakes. But it only works out if the person implements the input.
Now to the practical part. Dont worry about that temperature. I asure you its way over 300c, thats a measurement error. IR temhermometers only work accurately on dark, non reflective surfaces. Charcoal emits a lot of IR rays and it will mess up with the sensor.
A cast hearth is a huge heat sink. In the case of hearth design the best way is also the most simple and cheap, as l described in the beggining of the thread. The ashcone. Self repairing and insulative.
I also explained the importance of fuel preparation. Wich leads us to the most probable cause of your failed atempt. Fuel size is extremely important when it comes to gasifiers! In this case you want what we call “engine grade charcoal”. Crushed, dust sifted out and the peaces being between 3-15mm.
Your fuel simply didnt have enaugh surface area for the gases to react/reduce, also that explains the condensate. A well designed and fueled downdraft charcoal gasifier shuld never produce anything but rich dry gas.
Try doing this first and l asure you you will get a flare in 3 minutes not 3 hours. Tops.
Char gasifiers dont generaly need much draw to sustain a good flare, so l dubt your fan being week is a problem. Most fans however do not seal and are designed so that they pull a part of the air trugh the motor to cool it. In this case the gas will be too diluted to burn. You can tape down the air slits.
This is only true if you pull on the gasifier. If you push air in it makes no difference.
Best of luck and l hope you take this as it is ment, wishing only the best!
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Thanks Kristijan, I know how you mean about jumping in with both feet with no experience. Ive been guilty of that all my life- but thats how I learn- by innovation- not by copying. I don’t want to do what has been done when I can see what the results are already. You are right that a heavy steel wall burn pot will hold a lot of heat- but I know that refactory mix does the same. Thank you for taking the time to offer these comments.
The fuel is an easy fix, Ill remove it and crush and grade it. Ive just started making a rotary trommel- It will get used lots for other jobs too. Mushroom substrate preparation - compost prep. I have a lot going on here.
The fan pressure is dismal! The draught exiting the flare pipe is not enough to flutter a cigarette paper.
Is anyone here running double fans ? I could go parallel or in series.I wonder which would have more effect? the simplest way would be to insert an inline bilge blower straight after the squirrel cage blower in line and immediately entering the flare tube?
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Idealy you want a nice mix of fine and corse particles, you want the voids between larger peaces to be filled with finer stuff if that makes sence.
I understand your thod process perfectly as l was the same. Not so much anymore, l learnt it suits me better to skip things up and stand on the sholders of people before me.
You can also just use an compressor to blow air in the intake. You can get huge airflows that way (venturi effect). A temporairy test solution
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Yes - that was my first thought- but was nervous about causing a ‘woof’ - my partner is watching from behind the curtains. I must remain to appear competent haha. Tomorrow I will do this- then the booster blower if it improves. Ive played lots with forced air oil burners- https://youtu.be/A-KYIjcucrY
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Stuie,
I’m very much with Kristijan. Learn from others mistakes. Life is too short to make them all yourself. We could try building our projects out of rocks and trees, but I’d rather not. Well, I guess trees are not so bad. Still a lot of work though.
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Squirrel cage blowers aren’t really the best for a gasifier IMO, something like an inline bilge blower or a shopvac would be better at least for testing. Bilge blowers are what most of the truck and car guys use.
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LOL. My pipe gasifier did that for me. I looked at @k_vanlooken’s Some school Thailand thread and made my old Briggs geni run the very first time. I had no blower of any kind. I just used the suction from the engine. That old time mixture screw allowed me to wean it off liquid fuel as the gas started to come in. I came away feeling that I couldn’t miss. But I realized later that one MUST have at least 24 inches of char above the nozzle for it to work. As @KristijanL says 1/8-3/4 inch char works best, but I started with 1/2- 1-1/2 and it worked. I only got ~20 minutes run time at first, but as I screened out fines and added fresh char to the used, smaller pieces run times got a little longer.
Rindert
P.S. I had I cyclone filter on there at first but got rid of it later. Not needed.
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Morning Rindert- Its howling with wind and lashing rain here so I won’t be out there. Im pleased with the cooling effect of the cyclone, It’s stripping out the condensation well.- Granted- If I had not stored my char outside in the rain then I would have less moisture. My region is known for its high rainfall and constant 70% moisture. Now that I am a ‘Pyrologist’ 
I have to up my game. Ill build a roof, a trommel and Ill copy Matt’s char retort design that uses the flare to heat itself. Then I’ll have decent fuel.
Next- get a decent fan on board. As I was building it I was dubious that the 3 amp fan could pull though all that pipework- I discovered ages ago that when you slightly restrict the inlet of a squirrel cage fan - you absolutely kill the output. Thats why I questioned earlier why negative pressure is used. This weeks farmers market income will get misappropriated and spent on a big 4" inline fan
Thanks to everyone’s help Im understanding more and more.
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Save time go to big W or Kmart and buy a mattress inflator pump , or make a injector with your compressor , charcoal lights so easy and makes gas pretty damn fast so i would look at changing other area’s first , remember charcoal its self is the best insulator so the fastest way to to get some life into your machine would have to start with reducing the size of your charcoal .
The next issue is the 500 ml of condensate , was your charcoal damp ? did you leave it uncovered out side in wet or misty conditions ? I live half way up a mountain and i get low cloud in my garden most mornings everything is wet to the touch ,but my charcoal is in its drums stays dry and very little condensation , i also stopped using a cyclone i think sheep’s wool is one of the best ways at trapping the fine dust , The fan does not need to be as large as a bilge blower for charcoal in my opinion , but maybe your build is so different from the norm .
I am no expert everyone else on this site is smarter than me i can only say what i know from running Charcoal gasifiers that run flat out making power since 2012 and a blink of the eye now running wood gasifiers .
Only change 1 thing at a time .
Dave
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Thanks Dave - I appreciate the input- Yes my charcoal was in two fish bins pushed under the Land Rover to stay dry- not successful obviously!- Ive ordered a 10 amp 4" bilge blower- should be big enough to power a small hovercraft lol.
Uggh!- K Mart! I wont shop in a place that has no shop assistants but has 3 security staff on the doors!
Honestly- the air coming out the 50mm flare tube won’t even flutter a cigarette paper!
If this rain stops Ill get out there and shove the compressor hose down its throat - see what I get then
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Hey Stu, how far above that center hole of the hearth are your nozzles? I had imagined you’d put the nozzle tips right at the level the terra cotta pot begins.
Just judging from the perspective of the picture, it looks like the nozzles only have a few inches above that hole. Doesn’t give the reaction much distance to reduce through inert char. I’m surprised your gas temps aren’t a lot higher.
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