As experts in all aspects of dust control system specification, design and installation, including the duct work, we can make sure you have the right configuration for your process.

However, if you would like to take a look yourself, either at your current system or perhaps look into a new one, you may find these following calculations handy.

 

DUCT SIZING

 

UNITS USED

Air volumes are usually in – m³/hr.

For duct sizing it is better to be in – m³/sec (divide m³/hr by 3600 to obtain m³/sec).

 

DUCT VELOCITY

For conveying airborne dust, to ensure dust does not drop out of the airflow this should be 18 – 20m/sec for most dust types.

Consideration can be given to velocities higher or lower than this band bearing in mind the following:

  • Velocities can be lower if the dust load is very light or is a light bulk density
  • Velocities can be higher if the dust load is heavy and/or the product is a heavy bulk density

When selecting duct sizes, be aware of the duct type and manufacturer – some have differences in their size range.

 

CALCULATIONS

The following formulae includes all the values used in duct sizing:

 

DUCT AREA

Area (m²) = π (3.142) x Duct Radius² (m)

 

DUCT VELOCITY AND AIR VOLUME

Air Volume (m³/sec) = Duct Area (m²) x Air Velocity (m/sec)

These can be transposed to:

Area (m²) =  Volume (m³/sec) ÷ Velocity (m/sec)

Velocity (m/sec) =  Volume (m³/sec) ÷ Area (m²)