Optimizing Vibrating Screens for Industrial Applications

Learn how optimizing vibrating screen performance using Ansys Rocky.

Vibrating Screens

Vibrating screens play an important role in many bulk material handling processes, providing efficient particle separation and classification.

They are particularly common in mining, quarrying, construction, recycling, and food processing industries. Their design and operation require careful consideration of material properties, process requirements, and environmental factors to achieve optimal performance.

The use of Vibrating Screens provides different advantages such as the High throughput capacity, relatively low energy consumption, ability to handle a wide range of particle sizes, and finally, the Vibrating Screens can be used for wet or dry screening.

The performance is mainly affected by the Screen angle and deck configuration, the Vibration frequency and amplitude, the Material feed rate and characteristics, the Screen media type and aperture size, and the Moisture content of the material.

Description

Vibrating screens use mechanical vibration to move material across a screening surface (typically a mesh or perforated plate). The vibration causes particles smaller than the screen openings to pass through, while larger particles move across the surface. The classification may be presented as follows:

• Linear Motion Screens. Move material in a straight line path.
• Circular Motion Screens. Move material in a circular path.
• Elliptical Motion Screens: Combine linear and circular motions.
• Multi-Slope Screens. Use different angles along the screen length.

Some applications

• Sizing and classification of ores, aggregates, and minerals
• Dewatering of slurries
• Scalping (removal of oversized particles)
• Product purification and de-dusting

Simulation of Vibrating Screens

DEM (Discrete Element Method) is a numerical simulation technique that models individual particles in granular materials. It calculates particle motions and interactions, providing detailed insights into bulk material behavior in various industrial and natural processes. It reduces the need for physical prototypes, saving time and resources in the development process. Simulating vibrating screens with DEM is crucial for several reasons:

• It provides detailed insights into particle trajectories, segregation, stratification, and material flow patterns, which are difficult to observe in real-world operations, helping to design better feed and discharge systems.
  
  
• The screening capacity and efficiency can be accurately predicted under various operating conditions and for different material properties.
  
  
• Assessment of the complex interactions between particles and the screen surface to optimize screen design, vibration parameters, overall efficiency and high-wear areas.
  
  
• DEM simulations can be integrated into broader process simulations like the FEA-coupling.

Demo

The screen shown below is part of a simulation using Ansys Rocky. The geometry of the vibrating screen is given in STL format. Feed particles are defined by a particle Size Distribution (PSD) at the inlet. The screen's action results in overflow and underflow flows of particles that allow to calculate the screen efficiency. Translational vibration is defined by the amplitude, frequency, and phase.

Part I: Performance. In the following video, you will learn how to set up the model and use the results to calculate the screen efficiency for the given operating conditions. The postprocessing tasks allow to determine the screen efficiency is 67%.

Part II: Optimization. The setup of the previous simulation is now used as the starting point for the optimization in Ansys OpstiSLang. The video shows the procedure to define the input and output variables and obtain the screen efficiency, which reaches 98%.