Propane empty or not?
 

I have a plastic BP propane gas tank of 10 liters.
I was all ready to go and make some beads, and I ran out of gas. This is the first tank that I finshed, and I will exchange it for a full one. The thing that surprises me, though, is that there is still quite a bit left in there. Because it is a plastic tank, I can see through it. It looks to me like maybe 10% of the gas is still in there. When I unhooked the regulator (50 mbar) and opened the main cap, there was also still plenty of gas coming out. (quickly closed it ofcourse).
The regulator is supposed to lower the pressure to what your torch needs, right? Does it also stop the flow completely of the pressure falls below the needed pressure? That would mean that because the pressure is low, because most of the gas is used, I need to get a new one, even when it is not completely empty? I think most people that use these tanks for household things use it with a regulator for 30 mbar, so they would probably be able to use it longer.

Anyway....the trick now is to get it exchanged. No car, and these tanks are not allowed on public transport.

My experience is the tanks always have some unusable left in the bottom (kind of like a car gas tank).

If you truly run it completely empty (or its a brand new, never filled tank) they have to do something to it above the norm. (can't remember the term at the moment).

Keep in mind that the additives settle at the bottom of the tank.

Thanks for your replies. Probaby will head to the shop next week. I'm sure they'll also be able to tell me if something isn't what it is supposed to be.
I just thought I still had plenty.....and t have it suddenly run out is pretty annoying. However, I did not expect it to last me this long to begin with. I think the GTT cricket perhaps is a torch that does not use the gas that quickly. Or perhaps I do not have a clue, since it is the only one I ever worked on ;-)

Just like you all said, this is how all of these gastanks are returned. Guess it is never much of an issue with the regular gas tanks, as you cannot see some is left. People at the shop told me it does vary with temperature and what they use it for, but they are never completely empty.

Should not be much left in bottom of tank if any at all.... Propane is kept as a liquid when under pressure.... At approximately 70° f. (21 C.) tank pressure should be about 125 psi (1.01 bar) as tank pressure drops some and liquid boils off and tuns to vapor (typical LPG process of turning liquid to vapor), and you draw off vapor... This should process should continue to point where liquid is all gone... Regulator should continue to function till tank pressure is at same pressure regulator is adjusted to in other words no moer liquid to boil off into a vapor....

IF you have approx 10% liquid remaining in tank, either it is not propane (water?) of you have a tank valve or regulator problem.... You need to consult with "qualified" LPG technician to see what is going on with tank...

Dale

Dale, that is odd. The people selling the tanks, told me that all tanks come back to be switched with some still visible liquid remaining. The amount I had (may be less than 10%) was well within the range of what they consider normal. I have a set regulator, at 50 mbar, so it does not give any readings.

I have a fiberglass tank, and I can actually see the level of the liquid gas that is still left. On my first tank, I would mark it every month or so, to get an idea of how quickly I was using it. Very happy with these types of tanks. Also a lot less heavy than the metal ones.