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 stairway is not
a thing of gleaming strands
a radiant evanescence
for angels’ feet that only glance in their tread, and need not
touch the stone.”
—Denise Levertov (b. 1923)
“Every day, in this mostly male world, you have to figure out, “Do I get this by charming somebody? By being strong? Or by totally allowing my aggression out?” You’ve got to risk failure. The minute you want to keep power—you’ve become subservient, somebody who does work you don’t believe in.”
—Paula Weinstein (b. 1945)