I like the idea of an old canner-pressure cooker, particularly since we were "gifted" with a couple of big ones (even though we already HAD one).? It seems that few use them these days.? At least for canning/cooking :)? But that means they should be relatively easy to find at the thrift store or Goodwill.? Seals for the major brands still are available -- typically the seals on old pressure cookers are pretty much toast.
My scheme using a shop vac isn't suited for sucking out flammable stuff, since the shop-vac motor is right there and likely is a brushed type that generates lots of sparks (ka-BOOM!).? For that kind of thing I'd look at a so-called "elephant's head", basically a two-hole stopper arrangement -- one of the holes is to admit pressurized gas and the other for the liquid being pushed out of the container.? Clearly, the stopper must make a decent seal to the container opening.? I made one for moving home-made wine around, and the pressure source was a bicycle pump.? If THAT generates sparks you're doing something very wrong....
In the wine industry, the pressurized gas used to operate the elephant's head typically is nitrogen or carbon dioxide.? Either one would be pretty good for pushing flammables around as well.? Keeping oxygen away from your wine is desirable, hence the N2 or CO2.
Mark
