Hi Eodtek and EOD,Just a hunch,could it be the chemical container that fitted into the old conical type (like the "Pyrene") fire extinguishers,something similar was suspended in a cage inside the case of the extinguisher and when the plunger at the top was pushed it broke the glass and allowed the contents to mix with the liquid inside which caused a build up in pressure,the pipe feeding the nozzle went all the way to the bottom of the of the extinguisher whatever was inside,possibly just water then squirted out under pressure,much like shaking a can of coke then putting just a small hole in it,I could of course be barking up the wrong tree,if I am,my apologies,
regards,
Don,