I appreciate this good reply very much.
Your last two paragraphs are excellent explanations of what has been called “human-centered design.” A great reminder to give attention to the end user and the context in which the device/solution will be deployed.
Phapang design criteria is also a good advertising motto: “run whole day full load and maintenance is done in the blink of an eye.”
Thank you sharing your wisdom.
Hi Koen
With your oil bath filter, do you use other filters, cyclons, safety filters …?
Thierry
Hi Thierry,
On the pickup and Tuktuk, i only used the combined oilbath filter, a final safety filter could be a good idea, but i don’t have soot in my system so i don’t bother.
In the short run small engines, i just use foam
I can put any filter ( original paper, swimmingpool, or dirtbike filters) in line.
Its up to the machine i use and the purpose i am using said machine/engine
Since i never use the long term before maintenance schedule, it works just fine for me.
I really like this filter. it has a lot of advantages. It is compact, airtight valve, pressure relief valve, indicator of presence of water in the gas and probably low pressure drop … Have I forgotten something?
How about the temperature range? Looks easier to build than a bag filter.
No Thierry, you nailed it.
Yes Jeff, easy to build, easy to clean, and can be build for higher temperature if using some tin can materials.
Koen,
I’m considering trying your oil bath filter on my Toyota like the one on your Tuktuk—that is, if I have the skills to build it with readily available materials without welding. I get the idea from your diagrams how it works. Could you give more details regarding size of parts, suggested materials to use, and how to connect it all together?
Hi Steve,
I actually don’t have “fixed” sizes, i use any materials i have on hand. I do however make sure that i don’t choke the desired flows.
If my piping from the gasifier is 2" then any obstructive device is sized 3 times ( as example )
In the tuk tuk, the pvc pipe, vertical that is, was 4"
Just try to calculate the amount of oil, the level, above the slots, so that this does not requires a lot of vacuum to open those slots.
Koen,
Thanks for your reply. If I make the filter I would like it to only need minor changes to perform well. So, please excuse my many questions. Most of the gas flow lines in my system are 1.5 inches ID and I’m running a 1.6 liter engine.
Would a 5 gallon metal container with clamp lock lid be large enough for my purpose? I have a 7 gallon version, if that would be better. Does it work for the inlet and outlet to be through the removable lid? Is the outlet pipe with slots closed at the bottom? Do the stainless scrubbers go down where the slots are? If not, then how far above the slots would you suggest starting with the stainless scrubbers? I think you mention another filter material also. Where is it located? What depth of oil do you suggest I start with? Approximately how long are the slots? Why are they shown at an angle in your drawing? I notice that your starting blower doesn’t pull gas through the oil filter. Would it work to start up by pulling through the filter or does it require more vacuum than the typical start up blower would have?
Hope I’m not too much of a bother. Looking forward to your reply.
i use a VW oil bath filter as the last line of defence b4 it goes into my throtle body (front and center pic) very little restriction but very good filtration and renewable the housing is something to be desired but i supose i could build one of my own but this was on hand all ready
Hi Koen
I built an oil bath filter (inspired by yours) for the gasifier of my pickup. I don’t have fiber wands in the space between the gas supply and the oil bath. what are these fibers used for?
note: the oil quickly loads of impurities despite the two upstream cyclones of the filter.
Thierry
Hi Thierry,
I use the fibers as a kind of “magnet” for carbon particles, after i sprayed/soaked the fibrous materials with oil.
Yes, the oilbath is quite effective to clean the gas.
You say downstream, but do you mean the cyclone’s between gasifier and oilbath filter ? ( then i call that upstream )
you’re right i was talking upstream … Nothing escapes you my friend 
These oil bath filters are available on ebay and other places. Do you think they would work well as a final filter for charcoal gas and could it handle the volume of gas needed for my 1.6 liter Corolla engine?
I can answer the last part the volume wouldn’t be a peoblem they filter the volume of air needed by an engine that size on the orginal application. I would just go to tractor data and compare the engine spec of the motor you want to use with that displacement of the tractor motor the filter was designed for before buying. I would wait for @k_vanlooken to weigh in on using them the filtering ability he is probably one of the most knowable here on charcoal.
Oh I forgot to mention if you buy an oil bath filter make sure the metal screens are there. I don’t know if they sell them with the filter or separate but they definitely won’t work without the screens.
Ive had really good luck with the ammo box filters I make. I use pipe flanges to attach the pipe fittings. These flanges are used to make hand rails and things like that out of pipe fittings. They work well with sealant applied and mounted to a flat surface. Although the small ammo boxes maybe to small for you application but could go the larger ones and maybe use chainsaw dust in it. I use dust from my chop saw so its a bit finer.
I put kerosene mixed in with it to get the wood stove going. I might try this kero saw dust mixture in the filters as well but I dont think it really needs it. I still get a small amount of soot but no dust gets past this filter.
