Redrawing The Curve

Static screening technology has played a foundational role in coal processing for decades. The conventional sieve bend, also known as the DSM screen, is a widely used design that relies on curved, stainless steel wedge wires to classify particles in slurry flows without requiring any mechanical energy. Its static nature and simplicity have made it a mainstay in applications such as dewatering, desliming, and fine coal recovery. However, limitations in screen capacity, durability, and long-term efficiency continue to constrain its performance, particularly in modern, high-throughput coal preparation plants. Recognising these challenges, Derrick Corporation has developed a next-generation static screening system that significantly enhances performance while maintaining the zero-energy principle of traditional designs. The Derrick static screen introduces modularity, higher open area, and improved wear resistance, providing a superior practical alternative to conventional DSM screens. This article outlines the technological basis of Derrick’s latest innovation and presents field performance data from recent coal industry applications.

Limitations of traditional DSM screens

The curved profile and gravity-fed flow of DSM screens enable effective particle separation within a narrow size range. Yet, the design suffers from several well-documented issues:

• Material buildup and blinding: Over time, particles blind the openings and accumulate between wedge wires, reducing open area and decreasing efficiency.
• Wear of sharp edges: The stainless-steel wedge wires experience rounding and abrasion, dulling the separation interface and lowering throughput.
• Limited capacity: The physical constraints of wedge wire fabrication limit screen area, especially for fine aperture sizes, reducing the unit’s ability to handle larger slurry volumes.
• Frequent maintenance: Cleaning, replacing, or rotating screens imposes significant downtime and safety risks.

Although DSM screens remain widely used, these constraints often make them bottlenecks in plants seeking to expand capacity, reduce ash content, or improve recovery from fine coal streams. Unfortunately, little to no innovation has been made to this age-old technology.

Read the article online at: https://www.worldcoal.com/coal/22122025/redrawing-the-curve/