Simulation of Vibrating Screens

We will examine two screen models that are based on the traditional method that is used to size screens for industrial applications. These models are based on a series of capacity factors that can be used to determine the tonnage of a particular material that can be handled by a screen of specified mesh size. The traditional method does not attempt to make a realistic calculation of the size distribution in the oversize and undersize products from the screen. However this traditional model is convenient for preliminary simulations particularly in the early stages of a project when not much data is available and the precise details of the screens that are to be used are not known.

A useful modification to the traditional model was made by Dr. V.K. Karra who used an extensive collection of industrial data to model the actual screening process in terms of the physical parameters that define the screen operation. This model is to be preferred when simulating a screening operation for which the physical properties of the screen are known such as the simulation of a screening operation in an existing plant. The Karra model has proved to be reliable when compared against industrial operating data and is the recommended screen model for real plant simulation.

These models are described in Technical Notes 4 - Vibtrating Screens. The more fundamental kinetic model for screening is also described in these notes but its use will not be covered in this course because there is as yet insufficient operating data to make good estimates of the specific transmission rates for typical industrial screens. It is hoped that these data will become available in the future.

The traditional model is demonstrated in exercise 3-1 and the Karra model is demonstrated in exercise 3-2.