Cubic Feet Per Minute
Cubic feet per minute (CFM) is an often confusing term because it has no single definition that applies to all instances. In the most basic sense, CFM means cubic feet per minute. Unfortunately, gases are compressible, which means that a figure in cubic feet per minute cannot be compared with another figure when it comes the mass of the gas. To further confuse the issue, a centrifugal fan is a constant CFM device or a constant volume device. This means that, provided the fan speed remains constant, a centrifugal fan will pump a constant volume of air. This is not the same as pumping a constant mass of air. Again, the fan will pump the same volume, though not mass, at any other air density. This means that the air velocity in a system is the same even though mass flow rate through the fan is not.
Read more about this topic: Standard Cubic Feet Per Minute
Famous quotes containing the words cubic, feet and/or minute:
“Mining today is an affair of mathematics, of finance, of the latest in engineering skill. Cautious men behind polished desks in San Francisco figure out in advance the amount of metal to a cubic yard, the number of yards washed a day, the cost of each operation. They have no need of grubstakes.”
—Merle Colby, U.S. public relief program (1935-1943)
“The sugar maple is remarkable for its clean ankle. The groves of these trees looked like vast forest sheds, their branches stopping short at a uniform height, four or five feet from the ground, like eaves, as if they had been trimmed by art, so that you could look under and through the whole grove with its leafy canopy, as under a tent whose curtain is raised.”
—Henry David Thoreau (1817–1862)
“The minute you or anybody else knows what you are you are not it, you are what you or anybody else knows you are and as everything in living is made up of finding out what you are it is extraordinarily difficult really not to know what you are and yet to be that thing.”
—Gertrude Stein (1874–1946)