Thread: Gas science?

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I was reading my local newspaper yesterday, and it had a story that seemed hokey to me, but then again im not by any means educated in science and chemistry, so i will let you guys toss it around, and maybe someone can help my feeble brain wrap around this theory.


Basicly the story was that were getting screwed at the pump cause gas is measured as i think it was 361 cubic inches at 60 degrees is one gallon of gas, and that is what the pump is calibrated to, but in higher temps the gas expands so it takes more gas to equal the same energy, plus the pump is somehow shorting you gas , they said if you fill up at night when its cooler, you get more gas than if you fill up when its 100 degrees out, does this make any sence to you?

Well, I don't care about the science, but I know that my local gas "pusher" has "temperature compensated pumps", and now my tank that holds 15 Imp. Gallons will hold 17 or so. Can we say, "RIPOFF!"

1) Gasoline pumps compensate for termperature and density. Although it reads out in gallons the pump actually is measuring out the mass that goes through it.

2) Storage tanks are generally underground where the temperature does not fluxuate more than a couple degrees pretty much year around.

Your paper gets my BS flag.

Kitz

Your paper gets my BS flag.


Well there we have it!

I dont understand , if gas expands in hotter temps, then how come when you keep a gas can in the storage shed, it does not burst, if its full.

You guys have really got my attention with this point of fuel loss. My seminars and classes I have to attend cover a lot of this subject. I find my head nodding off in a sleep woven state and don't recall and have not taken the proper notes to fall back on. So, in the interest of my own curiosity, I asked my wife to pull some of her reg's from Valero. She is one of many fuel managers for the company. Interesting readings that the public doesn't recieve. Vaporization and fuel rates across the "reader" are not Accounted for. It is broken down by simple math and it is true you do lose a small amount of what you paid for in the "heat". Very miniscule at the time of purchase, But it does add up over a period of time such as a year's worth of fueling up. Just food for thought.

You probably lose more on the ground when you pull the nozzle out. Quit spilling.

[QUOTE=hotroddaddy]I was reading my local newspaper yesterday, and it had a story that seemed hokey to me, but then again im not by any means educated in science and chemistry, so i will let you guys toss it around, and maybe someone can help my feeble brain wrap around this theory.


Basicly the story was that were getting screwed at the pump cause gas is measured as i think it was 361 cubic inches at 60 degrees is one gallon of gas, and that is what the pump is calibrated to, but in higher temps the gas expands so it takes more gas to equal the same energy, plus the pump is somehow shorting you gas , they said if you fill up at night when its cooler, you get more gas than if you fill up when its 100 degrees out, does this make any sence to you? [/QUOTE
I'm pretty sure one gallon equals 231 cubic inches.

I'm pretty sure one gallon equals 231 cubic inches.

Hey at least i got the one right, thats why i said i think it was.

Let's have some fun with this...... Richard, and all of you that reside here in "HOT" Arizona. Fill when ever you wish and try to put your hand on the nozzle. Burns don't it?....

Here is an interesting page from Omega's site. Omega makes measurement equipment of all kinds.

http://www.omega.com/techref/flowmetertutorial.html

The comment in the article regarding the 24 hr stability of underground tanks is important.

mike in tucson where it's 102F right now and wonderful

Originally Posted by robot

mike in tucson where it's 102F right now and wonderful

Heck, all the snowbirds are gone . . . right?

Gotta love it here in the greater southwest. Denny, I filled two plastic gas cans@ 2:30 A.M. this morning. It was cool to the touch until the fuel hit the nozzle. We have to make jokes about our heat here to survive.

"Burns don't it?"
And how!

'Up here, it's nice and cool when you touch the metal part of the nozzle."
Yeah, but down here we don't have to shovel sunshine in the winter.

Originally Posted by hotroddaddy

I was reading my local newspaper yesterday, and it had a story that seemed hokey to me, but then again im not by any means educated in science and chemistry, so i will let you guys toss it around, and maybe someone can help my feeble brain wrap around this theory.


Basicly the story was that were getting screwed at the pump cause gas is measured as i think it was 361 cubic inches at 60 degrees is one gallon of gas, and that is what the pump is calibrated to, but in higher temps the gas expands so it takes more gas to equal the same energy, plus the pump is somehow shorting you gas , they said if you fill up at night when its cooler, you get more gas than if you fill up when its 100 degrees out, does this make any sence to you?

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I have noticed that one local bulk supplier has painted their above ground storage tanks black. In the summer around here, I imagine the temp of whatever is stored in them is substantial. I have wondered if it was to take advantage of thermal expansion to increase bulk. If they are selling tens of thousands of gallons annually, I wonder if there is any meaningful profit to be gained. Seems that loss due to evaporation would be significant in that situation. Unless, they have some kind of vapor recovery system.