Manual for the Design of Pipe Systems and Pumps - GEA ...

8.6 SI - Units
Legal units (Abstract for centrifugal pumps)
Designation Formula Legal units not admitted Conversion
symbols (the unit listed first units
should be used)
Length l m
km, cm, mm
base unit
Volume V m3 cm
cbm, cdm
3 , mm3 , (Liter)
Flow rate Q m 3 /h
Volumetric flow V m 3 /s, I/s
Time t s (second)
ms, min, h, d
base unit
Speed n 1/min
1/s
Mass m kg (Kilogram)
g, mg, (Tonne)
pound, centner base unit
Density ρ kg/m 3
kg/dm 3 , kg/cm 3
Force F N (Newton = kg m/s2 )
kN, mN
kp, Mp 1 kp = 9.81 N
Pressure p bar (bar = N/m 2 ) kp/cm 2 , at, 1 bar = 10 5 Pa = 0.1 MPa
Pa m WS, Torr, 1 at = 0.981 bar = 9.81 x 10 4 Pa
1 m WS = 0,98 bar
Energy, W, J (Joule = N m = W s) kp m 1 kp m = 9.81 J
Wort, Q kJ, Ws, kWh, kcal, cal 1 kcal = 4.1868 kJ
Heat amount 1 kWh = 3600 kJ
Flow head H m (Meter) m Fl.S.
Power P W (Watt = J/s = N m/s) kp m/s, PS 1 kp m/s = 9.81 W;
MW, kW 1 PS = 736 W
Temperature, T K (Kelvin) °K, grd base unit
t-difference °C
Kinematic ν m2 /s St (Stokes), °E,… 1St = 10-4 m2 /s
viscosity mm2/s 1 cSt = 1 mm2/s Approximation:
mm2/s = (7.32 x °E - 6.31/°E)
ν = η ρ
Dynamic η Pa s (Pascal seconds = N s/m 2) P (Poise), … 1P = 0.1 Pa s
viscosity
45
GEA Tuchenhagen