Translations:Pumpen, Betriebs- und Regenwasserwerke/150/en

$V_{n}={\frac {0.33\times 4.2\ {\frac {m^{2}}{h}}\times (6\ bar+1)}{((6\ bar\ -2.5\ bar)\times {\frac {20}{h}}\times 1)}}=0.139\ m^{3}=139\ l$