When designing a pneumatic conveying system, be aware of the consequences of compromise.
It is important to match the system design to the products you want to convey when designing a system, according to Jack Hilbert, principal engineering consultant with Pneumatic Conveying Consultants LLC.
“Too many times, that matchup is lacking or the end user settles for a compromise and then is forced to accept the consequence,” said Hilbert.
Hilbert discussed the ins and outs of pneumatic conveying at Powder & Bulk Solids Texas in October, as part of his conference presentation, “Pneumatic Conveying in the Room: System Design & Optimization Guidelines.”
During the presentation, Hilbert used a tabletop working pneumatic conveying system to demonstrate various principles of pneumatic conveying, conveying modes, and the consequences that can result if conveying lines are not correctly installed.
Hilbert’s intent was to show conference attendees the principles of pneumatic conveying and show the participants what happens with a working system.
“In my experience, when participants actually get to see the principles being demonstrated and they can make physical changes to the convey line routing and immediately see how the flow pattern changes – the understanding and retention of what is seen is more firmly imbedded in their memory,” said Hilbert.
Hilbert discussed some of the troubleshooting areas of pneumatic conveying, such as correcting convey line geometry problems and issues around the proper venting of the conveying system and components. He estimates that 95% of the problems with pneumatic conveying systems can be solved and corrected but another factor to consider is the cost to correct versus the cost to replace.
In Hilbert’s last 10 years of consulting, he estimated there has only been one case where a pneumatic conveying system was completely replaced because the cost and time to fix it was prohibitive.
Hilbert says that one of the keys to avoiding pneumatic conveying issues is for users to “talk to their material” before they design a system or select a component for that system. “Talk to the material” means that users should do some basic tests to determine the necessary physical properties of their material such as testing for bulk density, particle density, particle size distribution, how the material fluidizes and retains fluidization, and particle shape. Once a user knows more about their product, the user can group the material into one of four Geldart Classes that will provide guidelines as to what type(s) of systems to use, what type(s) to avoid, and where there may be some crossover.
And knowing more about your material makes a huge difference – it can very often mean the difference between success and failure, said Hilbert.