Graywolf
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The principle is the same. I have generated up about 45 psi in our test sled, setting the collection pot in hot water at boiling and read that someone's Tamisium generated 55 psi.
I personally design to 3X of maximum operating pressure, so I am planning a 150 pound system for our next generation of pumped recovery. The weak link in my new system is the o-ring gaskets, but I will install a 150 psi rupture disc. I would use a simple pressure relief safety valve, but most pressure relief valves are not also rated for vacuum.
I looked at stainless fire extinguisher bodies, but didn't use it for a collection tank, because It would be hard to remove the oil from and clean.
I am also trying to stay with a short fat tank, so as to have the maximum surface area exposed to the heat and vacuum, to optomize boiling.
I didn't consider an extinguisher as a butane storage and recovery tank, because tanks made for fuel gas are so readily available and inexpensive. Since they will only have butane in them, they don't have to be stainless either.
Extinguishers are also made to hold moderate pressure, but are usually not heavy walled enough to allow pulling a hard vacuum on without collapsing them. There are some stainless pressure tanks available on line new and used that are heavy enough, but none of them offer good access for cleaning.
Because I haven't found the perfect lower collection vessel at a reasonable price, I am presently planning to make ours out of 304 SS 10" Schedule 10 pipe, with a 3/8" plate on the bottom and a 1/2" plate for the lid. I have had those prints out for bids, but if I found a stainless paint pressure pot at a reasonable price, I would use it in a heartbeat. Alas so far I have not.
Here are three new columns, with triclamp closures, destined for our next prototypes.
