Quote:
Originally Posted by petek
and remember that a perfect vacuum is only 14.7 psi (and you'll never get perfection).
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This remind me of a something my transport (fluid dynamic) teacher told us once. When he got out of college he went to work in St. Louis in a plant right off the Mississippi. There was a recent fire at the plant and the fire pump truck tried to use water from the river but were unable to. One of my teachers first job was to figure out what went wrong. Aparently the pump truck had tossed a hose down into the Mississippi expecting to be able to pump it up to put out the fire, but the water was 90 feet below the pump truck. Since a perfect pump could only draw 33.9 feet of water (or 760 mm Hg, 14.7 psi, etc.) the pump truck had no chance of pump 90 feet up to the fire.