HomeProtein PurificationConverting from Flow Velocity to Volumetric Flow Rates

Converting from Flow Velocity to Volumetric Flow Rates

It is convenient when comparing results for columns of different sizes to express ﬂow as ﬂow velocity (cm/h). However, ﬂow is usually measured in volumetric ﬂow rate (ml/min). To convert between ﬂow velocity and volumetric ﬂow rate use one of the formulae below.

From ﬂow velocity (cm/h) to volumetric ﬂow rate (ml/min)

 Volumetric ﬂow rate (ml/min) = Flow velocity (cm/h) 60 × column cross sectional area (cm2)

 Volumetric ﬂow rate (ml/min) = Y 60 × π × d2 4

where

Y = ﬂow velocity in cm/h
d = column inner diameter in cm

Example:

What is the volumetric ﬂow rate in an XK 16/70 column (i.d. 1.6 cm) when the ﬂow velocity is 150 cm/h?
Y = ﬂow velocity = 150 cm/h
d = inner diameter of the column = 1.6 cm

 Volumetric ﬂow rate (ml/min) = 150 × π × 1.6 × 1.6 60 × 4 = 5.03 ml/min

From volumetric ﬂow rate (ml/min) to ﬂow velocity (cm/h)

 ﬂow velocity (cm/h) = Volumetric ﬂow rate (ml/min) × 60 column cross sectional area (cm2)

 ﬂow velocity (cm/h) = = Z × 60 × 4 π × d2

where
Z = volumetric ﬂow rate in ml/min
d = column inner diameter in cm

Example:

What is the linear ﬂow in a Tricorn 5/50 column (i.d. 0.5 cm) when the volumetric ﬂow rate is 1 ml/min?
Z = volumetric ﬂow rate = 1 ml/min
d = column inner diameter = 0.5 cm

 ﬂow velocity = 1 × 60 × 4 π × 0.5 × 0.5 = 305.6 cm/h

From volumetric ﬂow rate (ml/min) to using a syringe

1 ml/min = approximately 30 drops/min on a HiTrap 1 ml column
5 ml/min = approximately 120 drops/min on a HiTrap 5 ml column

Materials