We all like to say tar is impossible to filter out of woodgas, Mr Wayne even has a good expresion for it wich l forgot exactly, but is that realy the case?
I have been thinking about this for a long time, all starting when tar filters for cigarettes were popular. We used them for a while, they were like litle plastic mouthpeace that you put a cigarette in and dissasemble after each use, wipe off tar and put in pocket for further use. They worked amazingly well, to well sometimes. Harvesting a full drop of tar after each cigarette but allso robbing the smoke of most flavour.
How they worked was they had 3 tiny jets inside. Smoke went trugh them and hit a acrilic pipe wall, the high velocity smoke slamed the surface and you culd visualy see tar fall out.
The other day l tested the new gasifier with positive pressure wich it is not built for. The hopper is designed to be cool and smoke free with alowing some air to be sucked in and push smoke down, obviously not possible with positive pressure. Anyway, there was smoke in the hopper. After a while l stoped flareing and checked it all out, found a pinhole in the hopper weld with a strem of tar dripping out. But here is a interasting thing. There were cooler surface on that hopper with zero tar deposit, just some water droplets. But the high gas velocity pinhole did a good job at extracting tar!
Thinking further, this makes lots of sence. We see signs of tar in gas in the most turbolent parts of the engine first. Throtle plates, intake valves… but the question is, can this effect be utilised to be usefull to us? If nothing else, as a tar detector rather thain filter?