Different materials are capable of giving totally different conveying characteristics in a pneumatic conveying system pipeline. In dilute phase, suspension flow, conveying material flow rates can differ by as much as three to one for identical conveying conditions in terms of pressure drop and air flow rate for a given pipeline. In low velocity, dense phase, flow they can differ by more than twenty to one.

If you have a range of different materials to convey through the one pipeline you will have to set the material feed rate to the lowest value and the air flow rate to the highest value for the pressure drop that you have available if you have no control over the mix of material being fed into the pipeline.

In dilute phase conveying the residence time of the material in the pieline is very short and so just a small batch of a 'difficult' material, in the mix, will cause a rapid rise in pressure drop and could easily result in pipeline blockage. ■