Example: determine the pressure drop of a
valve with Kv = 0,5 , air flow rate ~6,5 Nm3/h and relative
upstream pressure 1 bar.
Solution: the absolute upstream pressure is
P1 = 1+1 = 2 bar absolute. On the chart start from the ordinate Q,
value 6,5 Nm3/h, go on horizontally until it crosses the
inclined line of Kv = 0,5 draw a vertical line until it crosses the
curve of the absolute upstream pressure P1 = 2 bar; and then you
continue horizontally until you read the pressure drop
Dp = 0,115 bar corresponding to ~ 1150 mmH2O.
Q =
flow rate in Nm3/h Kv = flow factor P1 = upstream absolute pression in bar P2 = downstream absolute pression in bar d = fluid density (air = 1)
