Equations
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Symbols
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GPM = gallons per minute |
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CFS = cubic feet per second |
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Lb. = pounds |
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Hr. = hours |
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BBL = barrel (42 gallons) |
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Sp.Gr. = specific gravity |
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H = head in feet |
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psi = pounds per square inch |
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In. Hg. = inches of mercury |
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hv = velocity head in feet |
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V = velocity in feet per second |
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g = 32.16 ft/sec2 (acceleration of gravity) |
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A = area in square inches |
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I.D. = inside diameter in inches |
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BHP = brake horsepower |
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Eff. = pump efficiency expressed as a decimal |
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Ns = specific speed |
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N = speed in revolutions per minute |
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v = peripheral velocity of an impeller in feet per second |
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D = Impeller in inches |
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Nc = critical speed |
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f = shaft deflection in inches |
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v = peripheral velocity of an impeller in feet per second |
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P = total force in pounds |
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L = bearing span in inches |
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m = constant usually between 48 and 75 for pump shafts |
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E = modules of elasticity, psi – 27 to 30 million for steel |
