This subject has always been a bit of as black art with rules of thumb, phrases like pick up velocity, solids loading ratio, particle acceleration at pickup and and re acceleration after bends.

I am greatful to Amrit Agarwal

Consulting Engineer

Pneumatic Conveying Consulting Services LLC

polypcc@aol.com

for sending me a copy of his calculation method published in Powder Handling and Processing magazine in its April 2005 issue, which gives the theory and all of the equations that are internally used in computer programs to do lean phase pneumatic conveying.

Amrit's paper describes all the forces and frictions subjected to the gas and product and goes onto descibe how all the formulas can be placed in an Excell spread sheet to calculate out your system.

I have not yet had time to fully understand all the formulas nor try them in a spread sheet but have found the first read very interesting and informative.

Anyone interested in the artical should contact Amrid direct as the information sent to me was to be for my use only.

Thank you again Amrid for enlightening me a little on this mystical subject. ■