Are you talking about a Rocket Mass Heater, Giorgio? I have one in my greenhouse. I’ll take some pictures. The people that run this site have lots of information. Down a ways on the page is some free plans.
Also. https://donkey32.proboards.com/
If I built another one I’d go with a batch heater. This guy is the authority
I know the principals and a few good designs.
It all depends on what you are trying to do with it.
Heat resistant packing rope.
99% of the time you can pick away at it and un-weave it to get strings.
You can mix and match different combinations of strings to make what ever size rope you need
Does not specifically matter where or what brand you buy you mix and braid it to fit the valve as required and snug up the valve to make a seal.
These things loosen up with use and you must adjust, repack valves to ensure a minimum of leaks.
Yes they will leak a tiny amount around the stem be aware…
This is what you are trying to create inside the valve
hello jacob and all others thanks for answers…the rocket stove should only be for emergency cooking outside, on google imagines there are a lot of pictures, but personally experiences count much more…so if you have some good plans i would be very happy…
my cooking gasifier works well now, the blower works with battery power from our household batteries system, or also with a simple photovoltaik paneel, but when the batteries are flat and when is cloudy sky, a rocket stove would be interesting…ciao giorgio
This guy has about a hundred stove builds Giorgio. You have probably already seen them.
I am not home for the rest of the week. When I get home I will post some pictures and designs.
I have several. Some very simple others built better and lasting longer.
Giorgio, l have found that much like with a engine, its important for a woodgas burner to have a lot of hydrogen in your gas to maintain good flame speed. Even thugh the gas is caloric, if the speed of combustion is low, heat transfer from flame to the pot is bad. Flames just lick the bottom and roll away from the side.
Second, l had the same problem. Once in a while bad gas came and away goes the flame. When l get back to this, l think what lm gonna do is add a pilot burner. Just a copper pipe with some cotton rope inside, leading to a small container with ethanol or something, and the tip of this “candle” being lit next to the woodgas burners. Does this make sence?
The -basic- design is a 1:3 ratio. 1 inlet 3 height.
If you are going to cook with it outside. I always like this one. 
I think this one is on wheels.
This is something along the same lines but he is using it indoors to make charcoal.
Note: it is on wheels, and he rolls it out of his shop to cook with I think in a different video.
I haven’t watched these in years though, and I am surprised I actually found them.
kristian, thanks for tipps, the aktual model with the 4 nozzles seems have a shure fuel flow, hours without interuption continuos flame, with 3/4" pipes on the stove…this seems shure for use, in opposit to the try with 1 nozzle, what creates easily bridging…than gas burning interruption.
with the hydrogen could be a good idea, with a dripper on the air inlet, there is very hot , could work. maybee one drop in second.
the next days when the cooker is ready i will make a try how much time is needed to bring a liter of water to boil…
my opinion is the burner lids of the propane stoves, though with updrilled holes like thoose i have modyfied, makes a ostacle for the heat transfer to the pot…
i think the security valves are not the solution for indoor use, because they are to narrow and for self made bigger diameters the magnet and the spring maybee too weak.
but for indoor use maybee a kind of cooking in the chest could work… around the cooker is a airthight -to the room -box, with a hermetic sealed door, when you cook, the door is open, and when you must go away for a while and let it cook, you close the door, and when you return you see if the flame yet burns or has gone of…no gas goes in the room if the flame for some reasons has gone off…the chest needs of course a air feed pipe in the bottom what comes from outside for the combustion air when the door is closed, and on top another pipe where the cooking vapours can go outside…this requires only a gasifier what burns shure without interruption…
you have suggested onc a simil system where the burner is inside of a mini stove, all hermetic closed to the room, this can also work, but i think with direct fireing under the pot is more effective instead heating a metall plate from underneath where the pot stands on…
Excuse the dirth, but this is how our stove looks like
When we cook, we take the rings off. There is plenty of draft so nothing gets out and lm sure l can safely install a woodgas burner in this stove.
with this chimney draft seems optimal., also when gas flame goes off, the poisoness gas goes through the chimney away…
we have only a short chimney on our house stove, very less draft, yesterday we modyfied the cooker pipes with 3/4"
Giorgio, what kind of machine is this?
Thanks for reminding me, on the edge of our property is a semetery and next to it a garbage container for cemetery waste, but people throw all sorts of stuff in. I salvaged 2 microwawes for transformers, perfectly good kids bicycles… yesterday l saw in it a hevy heat exchanger, with a fan. Shuld be great for heating a shop or for a dryer.
The North family have a good solar drier, chimney style. Perhaps @JocundJake culd take a picture for you?
Other thain that, l found air flow is much more important thain heat. You only need to heat air a litle bit to drop its humidity. We dry apples most of all fruit. Its our kids favourite snack.
Plumbs we dry too but not many as we dont fancy them that much, only a kilo or two for flavouring a venison roast gravy or goulash.
My mother has luck with making fruit leather. You blitz your fruit in a pulp, then spread thinly on baking paper and dry to a firm, leather like form. Cut and roll in to small rolls to be eaten as a snack. Works with plumbs too!
the machine is a old normal meat cutter for sausage making…the gear i made by myself , otherwise only with the crank handle your arm fall off because it has not the right speed.
we use for tomatos, figs , all fruit.
this kind of plums is relative small, but really honey sweet, so, a bigger quantity to have is not wrong… other races of plums are more sour, we have planted a lot of different races, for to see what grows well and tastes good also
.the apples here soffers much because of too dry climate, nearly nothing to use now…
in the 90ties they were nice, now not more.
the leather recipe of your mum is interesting…will try
the dryer of north family is interesting for me, jacob will send me also some designs for rocket stoves, when he return at home…so i will ask him also for the dryer…
you are lucky with the garbage container nearby!!
for me, without car, is all mostly out of reach…
Tom, was faster.
Wanted to give this link
It is translated in Italian and he really is an authority. I know him in person. He dedicated his life for developing the batchrocket and is about to get it certified here in the EU. Lots of rules , emission etc. Like the WK gasifier, you know what you get/ are building.
