tacktical mass catering with vandenberg venturi
Jan 29, 2017 11:35:30 GMT -8
matthewwalker, DCish, and 2 more like this
Post by jono on Jan 29, 2017 11:35:30 GMT -8
this is a quick documentation of an extreamly time pressured build. the goal was to make a rocket stove cooker that I could carry, take on a train, which could feed 100+ people fueled by twigs. The project started after dinner on thursday. I made these two shapes out of cardboard
my wife bought those two bottles of cider from the corner shop because they are exactly the same external diameter as the steel pipe i will use, which meant i could work inside. it was dark and raining. the cardboard shape that is already taped to the bottle is the internal mold, the larger shape above is the external mold, it was taped to the bottle then cut to create a seam that allowed me to spoon reafractory concrete into the mold, and tamp it down into the corners, taping up the seam as i filled the mold. here I am looking very smug about the process
and here it is on my vibrating table. note the shoe wedged in between the washing machine and the wall. this is very bad for the bearings in your washing machine, only a complete idiot would do such a thing
thats thursday evening. on friday morning i demoulded the refractory secondary combustion chamber (the cardboard came out very easily as it was substantialy softened by the moisture it absorbed form the concrete. Then I made the metal fire box out of a piece of 3.5inch heavy guage metal pipe, a piece of plate metal, an angle grinder and . this is what it looks like
I tied the still green secondary combustion chamber on to this fire box and got a fire going in it to speed cure the refractory concrete with heat. this is how the two components fit together, followed by a view in to the secondary combustion chamber
whilst the secondary combustion chamber was curing, i set to work modifying a barrel pot stand. it used to work with a long chimney and be a full size barrel with a different firebox that fell to pieces through use. well, the sequence in which i did the work is probably not relevant. by friday evening i had this
which, though not the easiest thing to lug around, is much more transportable than the previous version. so, on satarday about a hundred people were protesting outside a coal fired power station, and where fed by this (the above, assembled for use)
you can see the metal fire box into which wood is fed. here is what it looks like from above with the pot removed. you can see the slots around the perimiter of the pot stand out of which the combustion gasses escape, and in the center you can see the top of the heat riser, right down into the venturi slot between the firebox and the secondary combustion chamber.
here is what it looks like from bellow. i have wrapped the firebox in ceramic insulation which is held in place with aluminum tape. not a robust long term solution, but as a temporary fix it got the job done
it needs a lot of refinement of course. when i get time ill add a secondary combustion air feed and encase the firebox/secondary combustion chamber and heat riser in insulation with a sheet metal surround. what i can say is that, even as unfinnished as this was, it was a pleasure to cook on. burnt smokelessly most of the time, the fire was easy to see and to refuel without bending, it got hot very quickly and consumed very little fuel to get there and the pot surround stayed reasonably cool (ie, not hot enough to burn anyone)
my wife bought those two bottles of cider from the corner shop because they are exactly the same external diameter as the steel pipe i will use, which meant i could work inside. it was dark and raining. the cardboard shape that is already taped to the bottle is the internal mold, the larger shape above is the external mold, it was taped to the bottle then cut to create a seam that allowed me to spoon reafractory concrete into the mold, and tamp it down into the corners, taping up the seam as i filled the mold. here I am looking very smug about the process
and here it is on my vibrating table. note the shoe wedged in between the washing machine and the wall. this is very bad for the bearings in your washing machine, only a complete idiot would do such a thing
thats thursday evening. on friday morning i demoulded the refractory secondary combustion chamber (the cardboard came out very easily as it was substantialy softened by the moisture it absorbed form the concrete. Then I made the metal fire box out of a piece of 3.5inch heavy guage metal pipe, a piece of plate metal, an angle grinder and . this is what it looks like
I tied the still green secondary combustion chamber on to this fire box and got a fire going in it to speed cure the refractory concrete with heat. this is how the two components fit together, followed by a view in to the secondary combustion chamber
whilst the secondary combustion chamber was curing, i set to work modifying a barrel pot stand. it used to work with a long chimney and be a full size barrel with a different firebox that fell to pieces through use. well, the sequence in which i did the work is probably not relevant. by friday evening i had this
which, though not the easiest thing to lug around, is much more transportable than the previous version. so, on satarday about a hundred people were protesting outside a coal fired power station, and where fed by this (the above, assembled for use)
you can see the metal fire box into which wood is fed. here is what it looks like from above with the pot removed. you can see the slots around the perimiter of the pot stand out of which the combustion gasses escape, and in the center you can see the top of the heat riser, right down into the venturi slot between the firebox and the secondary combustion chamber.
here is what it looks like from bellow. i have wrapped the firebox in ceramic insulation which is held in place with aluminum tape. not a robust long term solution, but as a temporary fix it got the job done
it needs a lot of refinement of course. when i get time ill add a secondary combustion air feed and encase the firebox/secondary combustion chamber and heat riser in insulation with a sheet metal surround. what i can say is that, even as unfinnished as this was, it was a pleasure to cook on. burnt smokelessly most of the time, the fire was easy to see and to refuel without bending, it got hot very quickly and consumed very little fuel to get there and the pot surround stayed reasonably cool (ie, not hot enough to burn anyone)
