Boyles gas law and a good flow meter such as a Deleval milk house vacuum guage kit.

Air temperature also plays a huge role that can not be overlooked! ■

Minimum conveying velocity is not only a function material properties it is also dependent on pipe diameter. For materials with bulk densities up to1400 kg/m3 and particle size less then 1 mm 15 m/s in a 4 inch pipe is a safe starting point.

This is not a rule of thumb and there are some exceptions !!! ■

dear JimLee,

Use the search function in this forum.

(second button from the right in the second row of buttons at the top of the page) using

keyword : suspension velocity

and

search forums : pneumatic conveying

and you will be presented with 25 Topics

success

teus ■

Minimum conveying air velocity is not a design parameter that can readily be calculated. 15 m/s, as Mantoo says, is a good starting point, but only if the material has a wide size distribution. If it is a material like granulated sugar with a very narrow size distribuition then 18 m/s would be a better bet.

But that is for dilute phase suspension flow. If you have a high pressure gradient available, and the material has either very good air retention or very good permeability, you should be able to convey the material in dense phase, non suspension flow, at a very much lower velocity - say 5 to 8 m/s. ■