How to determine duct sizes from calculated pressure drops?

[oaskar]

I'm trying to redesign a pneumatic transport system, so I know that the optimum velocity to move my product is 5000 fpm and i know our production rates, my question is how do i know if the current duct sizes are suitable for the new air volume that i assumed

 

[SeanB]

If you know the current duct size you can calculate the cross sectional area. Using that and your production rate you can calculate the velocity throught the duct.

 

[siretb]

Have a look at Perry's handbook, fifth edition, on pages 7-21 and 7-22 you will find useful nomographs that answer your question.