Propane fill question
OK I am officially confused. I took one of my 40lb. propane cylinders out of my new RV to have it filled. A note on the door of the propane compartment said do not fill over 80%, could cause fire,e...
Forum Discussion
When filled to 100% the pressure rises over partial pressure since there ain't no space for vapor. Anytime there is both liquid and gas, the pressure is based on the temperature. http://www.engineeringtoolbox.com/propane-vapor-pressure-d_1020.html
We have OPDs today since 100% filling was not impossible.
Overfill when cool and then let it warm up and the cylinder is overfull (all liquid). When warmed, the pressure rises (liquid expands), the gas condenses into liquid, 100% liquid and the pressure rises sharply since there is no more gas to compress, eventually the relief valves opens (since the liquid doesn't compress much).
Using the proper liquid level gauge (not the fixed ones in cylinder valves), one can fill to 95% by volume if the liquid is 130F, this is equivalent to 80% by volume 40F.
40# is 40# at zero F, 40F or 100F. 40# @ zero F is less volume than 40# @ 100F.
We have OPDs today since 100% filling was not impossible.
Overfill when cool and then let it warm up and the cylinder is overfull (all liquid). When warmed, the pressure rises (liquid expands), the gas condenses into liquid, 100% liquid and the pressure rises sharply since there is no more gas to compress, eventually the relief valves opens (since the liquid doesn't compress much).
Using the proper liquid level gauge (not the fixed ones in cylinder valves), one can fill to 95% by volume if the liquid is 130F, this is equivalent to 80% by volume 40F.
40# is 40# at zero F, 40F or 100F. 40# @ zero F is less volume than 40# @ 100F.
