Issue link: https://www.e-digitaleditions.com/i/1252179
June 2020 / 17 For further reading Find more information on this topic in articles listed under "Agglomeration" in Powder and Bulk Engineering's article index in the December 2019 issue or the article archive on PBE's website, www.powderbulk.com. Greg Mehos, PE (greg@mehos.net, 978-799-7311), is a chemical engi- neering consultant who specializes in bulk solids handling, storage, and processing and is an adjunct professor at the University of Rhode Island. He received his BS and PhD in chemical engineering from the University of Colorado and his masters from the University of Dela- ware. He's a Fellow of the American Institute of Chemical Engineers. and the ring's top should be chosen so that the particles impact either the teeth in the ring or fall through the gaps between. Designing the dispersion cone device so that the ring's location can be moved is recommended. Also, discrete ele- ment method (DEM) modeling can be used to fine-tune the device's design but isn't required to do so. DEM is a software-operated numer- ical method for modeling the bulk behavior of granular materials, including those with a distribution of particles. PBE References 1. Lyn Bates, User Guide to Segregation, British Materials Handling Board/Bar- tham Press, London, 1997. reaching the ring and is dependent upon the ring's placement, should be chosen such that the particles impact the extensions from the ring. Combining equations for X and Y and then simplifying yields Y = X tanα + g X 2 2 V 2 cos α where Y is still the vertical distance the particles travel after leaving the cone and reaching the ring. [Editor's note: For a list of each variable and its meaning, see Table I.] When determining the cone and ring size and placement, there are a few important things to keep in mind. The cone's diameter, D, should be approximately one-third of the bin's diameter. Then, the distance between the cone's bottom Variable Value V 0 Velocity before impact (free-fall velocity) g Acceleration due to gravity h Drop height V 1 Velocity after impact θ Impact angle ϕ′ Angle of wall friction (the inverse tangent of the friction coefficient) a Particle acceleration α Cone's angle (measured from horizontal) V 2 Velocity upon reaching the cone's end s Distance the particles travel D Cone's diameter H Cone's height X Difference between the radii of the cone and the ring t Time Y Vertical distance the particles travel after leaving the cone and reaching the ring TABLE 1 Legend for equation variables KEEP THE LATEST INFORMATION AT YOUR FINGERTIPS. WWW.POWDERBULK.COM/SUBSCRIBE