With oil prices hitting US$100 per barrel and the tsunami effect it has been having on gas prices at the pump, I think this bit of info I got in my email might be helpful.
1. Fill up your car or truck in the morning when the temperature is
still cool. Remember that all service stations have their storage tanks
buried below ground; and the colder the ground, the denser the gasoline.
When it gets warmer gasoline expands, so if you're filling up in the
afternoon or in the evening, what should be a gallon is not exactly a gallon. In the petroleum business, the specific gravity and temperature of the fuel (gasoline, diesel, jet
fuel, ethanol and other petroleum products) are significant. Every
truckload that we load is temperature-compensated so that the indicated
gallonage is actually the amount pumped. A one-degree rise in
temperature is a big deal for businesses, but service stations don't
have temperature compensation at their pumps.
2. If a tanker truck is filling the station's tank at the time you want
to buy gas, do not fill up; most likely dirt and sludge in the tank is
being stirred up when gas is being delivered, and you might be
transferring that dirt from the bottom of their tank into your car's
tank.
3. Fill up when your gas tank is half-full (or half-empty), because the
more gas you have in your tank the less air there is and gasoline
evaporates rapidly, especially when it's warm. (Gasoline storage tanks
have an internal floating 'roof' membrane to act as a barrier between
the gas and the atmosphere, thereby minimizing evaporation.)
4. If you look at the trigger you'll see that it has three delivery
settings: slow, medium and high. When you're filling up do not squeeze
the trigger of the nozzle to the high setting. You should be pumping at
the slow setting, thereby minimizing vapors created while you are
pumping. Hoses at the pump are corrugated; the corrugations act as a
return path for vapor recovery from gas that already has been metered. If you are pumping at the high setting, the agitated gasoline contains more vapor, which is being
sucked back into the underground tank, so you're getting less gas for
your money. Hope this will help ease your 'pain at the pump'
1. Fill up your car or truck in the morning when the temperature is
still cool. Remember that all service stations have their storage tanks
buried below ground; and the colder the ground, the denser the gasoline.
When it gets warmer gasoline expands, so if you're filling up in the
afternoon or in the evening, what should be a gallon is not exactly a gallon. In the petroleum business, the specific gravity and temperature of the fuel (gasoline, diesel, jet
fuel, ethanol and other petroleum products) are significant. Every
truckload that we load is temperature-compensated so that the indicated
gallonage is actually the amount pumped. A one-degree rise in
temperature is a big deal for businesses, but service stations don't
have temperature compensation at their pumps.
2. If a tanker truck is filling the station's tank at the time you want
to buy gas, do not fill up; most likely dirt and sludge in the tank is
being stirred up when gas is being delivered, and you might be
transferring that dirt from the bottom of their tank into your car's
tank.
3. Fill up when your gas tank is half-full (or half-empty), because the
more gas you have in your tank the less air there is and gasoline
evaporates rapidly, especially when it's warm. (Gasoline storage tanks
have an internal floating 'roof' membrane to act as a barrier between
the gas and the atmosphere, thereby minimizing evaporation.)
4. If you look at the trigger you'll see that it has three delivery
settings: slow, medium and high. When you're filling up do not squeeze
the trigger of the nozzle to the high setting. You should be pumping at
the slow setting, thereby minimizing vapors created while you are
pumping. Hoses at the pump are corrugated; the corrugations act as a
return path for vapor recovery from gas that already has been metered. If you are pumping at the high setting, the agitated gasoline contains more vapor, which is being
sucked back into the underground tank, so you're getting less gas for
your money. Hope this will help ease your 'pain at the pump'
