Mysterious Propane "Leak"
Sorry about the length but I hope with enough details someone can explain what is a mystery to me. After 5 years or so my propane pigtails had hardened. Since the regulator was the original from...
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PV=nRT applies to all gases including propane. I showed the calculations above for the variation in temperature that occurred for my last leak test. Temperature for the universal gas law is expressed in degrees Kelvin. A drop of 10 degrees F was only about a drop of a bit over 1% in Kelvin degrees so the pressure would have dropped by that same small amount.
The tables cited by 3tons are for vapor pressure over liquid and would not apply for a leak test with no liquid in the system and the tank valve closed. The tables are quite useful for other purposes. As we can easily experience vapor pressure of gaseous propane over liquid propane changes greatly with temperature. This reflects a decrease in the rate at which gas can be produced from liquid propane. The tables show a substantial drop in the ability of various sized propane tanks to provide gas for heating or other purposes. The drop is so bad I long ago stopped trying to use a propane BBQ in the winter months.
The tables cited by 3tons are for vapor pressure over liquid and would not apply for a leak test with no liquid in the system and the tank valve closed. The tables are quite useful for other purposes. As we can easily experience vapor pressure of gaseous propane over liquid propane changes greatly with temperature. This reflects a decrease in the rate at which gas can be produced from liquid propane. The tables show a substantial drop in the ability of various sized propane tanks to provide gas for heating or other purposes. The drop is so bad I long ago stopped trying to use a propane BBQ in the winter months.
