Quote:
Originally Posted by Chateau_Nomad
The local outfit where I get my propane explained it this way - after I noticed it wasn't completely full according to the tank gauge:
"FULL" in a propane tank takes into account the expansion and internal pressure of the tank. Propane is stored as a "liquid propane gas" (LPG) which changes from a liquid to a gas before it is expelled under pressure from the tank. That conversion happens VERY quickly - as does expansion of the tank contents from external heat.
There is what's called the "80% Rule" with propane. 20% of the tank MUST be available for expansion - both to allow for the conversion from liquid to gas, AND for expansion from external heating of the tank and contents. Thus, tanks should never be filled to more than 80% of capacity.
Anyone who fills beyond that 80% point is both ignorant of the extreme explosion risk, and doesn't respect common safety procedures.  |
That is what the bleed valve is all about. There are tubes in tank that travel up into the 20% vapor area. The output for the coach is one and all the appliances only use vapor and not liquid. The bleed valve should be opened when filling the thank and when the liquid reaches the 80% mark liquid will come out of the bleed valve. That is when the tank is full leaving 20% above the liquid for vapor.
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