Make a note of this pump's F number, also known as its Flow Fluctuation Figure. Use the F number with the % residual fluctuation required figure from the smoothness shown for each type of application. These two figures, the F figure and the % figure, applied to the size selection formula give you the smallest practicable damper size. See below for figures
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Find the "F" Valve of Your Pump - "F" is a correction Factor on the square of number of displacers.
Example, Centrifugals are intrinsically good - have a high F, Sandwich diaphragm metering pumps have a low F.
F = 1.8
The F figure assumes that the air supply to the A.O.D.D. is enough to ensure no return stroke delay.
An air operated double end diaphragm pump empties a 40 gals. drum in 4 mins., on a 2 second cycle
10 gals per minute x 231 in3 per gallon / 2 diaphragms per cycle x 30 cycles per min. = 38 in3 per end
@ 1.0 Hz.
Find your % residual fluctuation required figure
from the smoothness shown for each type of application. GO TO