I was planing on using a ultrasonic sensor for the fuel level since that is what Im used to, but I might have to rethink that since the temperatures up there might get too high, a regular flapp lever might be the easy way.
I have a few stiring motors laying around that I was planing on using to prevent bridging, shaker would probably do the trick too but the noice and mecanical wear would be higher.
I have found some interesting documents regarding grid connection, production units under 20kW are concidered unsignificant and have way less paperwork to get approved.
The document in Norwegian, but you can read it Jan-Ola.
If you use a vibrator and use a small starter motor, it will last you a very long time. They are designed to withstand the side loading and as long as you dont make it to aggressive it wont be any loader than your engine running. You just want a high frequency to keep the fuel from hanging up, its better to have short burst with a milder shaker than a big thumping thing scaring the crap out of everyone. 
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Hehe yes that is true, what about automatic ash cleaner? Would a auger system be best?
Yes but its more things that can break and requires more power. Just build your ash bin large enough to go for a day with an easy clean out system. If you look at our systems I build them so they have a full access door and can be cleaned very quickly. If you have grid back up then shutting down of a few minutes is no big deal the unit will fire right back up.
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Ill only run the gasifier 7-10 hrs a day in the beginning so in short runs it wont be a problem, and I have no idea of ash production yet on the two litre engine at 10-20kW load.
Probably should be large enough capacity of around 10 gallons of char. Just a guesstimate based on the V8 machines we used to produce.
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What about wear of the heart area and the nosles there? do you use nosles that goes in to the heart or just short ones just through the wall?
I have never seen any wear inside our hearths. The nozzles can melt a bit over time but last a very long time if the machine is always kept under control. I use SS for my nozzles and also our hearth bowl. The hearth bowl is 1/4" thick wall and I have yet to see one degrade. The inner shell generally if cleaned out will look almost as if it were sand blasted but no wear, corrosion or heat degradation. Leave it outside and let moisture and air inside then yes you will ruin it.
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Your hopper vessel and your filter or anywhere moisture can drop and come in contact with the metal are all prone to corrosion. This especially a concern when its in operative. The hopper is always subject as you will expose oxygen inside every time you open the lid. The rest of the filter while under operation is oxygen free; however if it sits it will most likely get some exposure. I use an industrial coating on the inside of all filtration that is not subject to intense heat. Basically every part that follows the gasifier even the cyclone gets this treatment.
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Most of my gasifier is going to be made of 316ss or 306ss, but my main chip storage is on the roof of the container and that would only have steel plates and wood walls.
Ill auger from the roof down to the 306ss hopper.
I might have to use ss floring since I plan on predrying the wood chip up there.
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If my translation is correct and my knowledge up to date, then its about the exciting current for the coils. If no grid power, your async generator will not produce electric. Only if you have a selfexiting sytem or a selfmagnetizing coil, then a automated system to cut the connection is needed.
a: However, the less then 3 % slip rule, lessens the efficiency or the power output for the generator.
b: The correct speed governor is the weak link and thus going to be your focal point, hence join the club.
c: I think Matt is the closest to perfection regarding governing and controlling, the market available controls are not realy suited for woodgas use and lack the ability to maintain the governed speed with gasfluctuations as is the case with fresh woodgas.
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So you´re good to go. Plug and play 
Oh, and from what I understood the maximum 3% rule was about voltage. No problem with your âunsignificantâ generator. The grid won´t notice, no more that running the motor in a normal way.
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Hi Koen,
on a: this is that you need to be within 3% of the voltage of the grid, this is no problem at all since my tiny 10-20kW generator cant do much of anything to the rigid grid, your motor protection would trip way before that.
When it comes to b: there is almost no need for governing a asynchron generator, you set the load your motor is comfortable with, about 30% flutuation of the rpm before you stop producing.
C: Yes I agree that he has great talent and experience with this, hopefully I can learn some tricks from him too 
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Yes Jan-Ola this is great news, as long as I stay under 20kW production, the need for documentation is bareable, also proof of concept is within what I can document.
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I guess you could use about the size gasifier i use on the Rabbit. I stopped emptying char from the dump last spring. I empty a mix of char and soot from the cyclone collector. About one liter for every hour of runtime.
I use ss and I haven´t noticed any wear yet in 15000 km. However that´s only equivalent to a week or two of running 24/7.
My nozzles protrude less than one cm. I use thin 2mm protective shields flush to the firetube wall. The shields may not be necessary but it should be a quick fix to change them out if I they do get worn out.
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What do you think of the size of my materials for the gasifier Jan-Ola, I havent decided 100% yet the size of heart, I hear you guys dont use a metal hourglas shape heart.
I could use threaded ss rod bored up as my nosles and counter nut on the inside.
I have a lathe at home and larger ones at work to make most of what I need.
Found your 8" builder page and studying that now.
First of all I´d like to say I don´t recomend you copy my build. It´s my first build and it´s very experimental. I don´t want to lead you down the wrong path.
Also it´s dimentioned for about 5 cm dia chunks. I get the feeling you should go with smaller internals if you want to run chips. Using chips you get a larger total fuel surface area and you may have trouble running hot enough to avoid tar if the heart volume is to big.
There are a few others on the site running chips. They may be better suited to give advice about heart size.
I see right now you found my thread.
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I think that if I use longer nosles toward the heart it should be ok for wood chips.