In waste processing facilities nationwide, sizing and recycling incoming material streams are routine operations. Facility managers utilize sizing equipment to decrease material volume, separate reusable items, and produce valuable end products. Selecting the most efficient processing equipment is essential for managing specific material streams effectively.

Low-speed shredders and high-speed grinders are common equipment types for handling wood, construction and demolition (C&D) materials, and municipal solid waste (MSW). Understanding the distinctions between these machines and their optimal material processing capabilities can greatly enhance a facility's throughput.

Types of Waste Sizing Equipment:

Low-speed shredders and high-speed grinders are frequently employed to process various materials. Low-speed shredders are categorized based on the number of shafts, which range from one to four. High-speed grinders include both horizontal grinders and tub grinders.

The decision between these machines depends on multiple factors, such as the material's type, size, and shape, the facility's location, and the desired end product. For instance, shredders are ideal for recycling operations and handling materials with potential contaminants like metal objects. Conversely, tub and horizontal grinders are often preferred for processing clean organic wood waste due to their efficient size reduction capabilities compared to most shredders.

Advantages of Low-Speed Shredders:

Low-speed shredders are versatile and excel at processing contaminated materials due to their low rotor speed and high torque. They can manage various material streams, including C&D debris, contaminated green waste, MSW, storm debris, and land clearing operations. These shredders are typically used as primary grinders because they are less likely to suffer damage from ferrous contaminants in the material stream.

Additionally, shredders are highly effective at handling materials like railroad ties and heavy C&D debris. Equipped with cross magnets, they can remove ferrous metals, enabling companies to process a broader range of materials and potentially generate new revenue streams. After metal removal, horizontal or tub grinders can be used to size the final product. Shredders also efficiently process certain synthetic materials mixed with other streams, making them suitable for smaller waste facilities or urban areas. They offer fuel efficiency, quiet operation, minimal dust production, and a lower likelihood of projecting objects long distances.

Drawbacks of Shredders:

Despite their advantages, shredders' slow rotor speed results in longer processing times compared to high-speed grinders. Shredders produce chunky, inconsistent product sizes that may require further processing depending on the final product's intended use.

Maintenance accessibility is another concern. Many shredders have limited access to engine compartments, rotors, and combs. However, models like the Vermeer LS3600TX low-speed shredder emphasize serviceability. The LS3600TX design provides clear access to components, including large engine bay doors, multiple ladder points, and a service platform. It also features a reversible mechanical transmission for efficient power transfer and a torque limiter that automatically disengages the drive at maximum torque, protecting critical machine components.

Benefits of High-Speed Grinders:

High-speed grinders, including tub and horizontal grinders, are engineered for speed and productivity. They utilize hammer mills that spin rapidly, from 800 to 1,300 rpm, allowing faster material processing than low-speed shredders. This makes them ideal for facilities that prioritize throughput. These grinders deliver consistent material sizing with interchangeable screens, allowing for the production of various material sizes based on operational needs.

Limitations of Grinders:

The high rotational speed of grinders makes them more susceptible to component damage from contaminants. They also produce more noise and can project objects further (especially tub grinders) than low-speed shredders, necessitating more operating space.

Combining High-Speed Grinders and Low-Speed Shredders:

Facilities can benefit from using high-speed grinders and low-speed shredders together. Using a low-speed shredder at the initial shredding stage, contaminants can be safely removed before the material is processed by high-speed grinders for final sizing. This combined approach can extend the lifespan of wear parts on secondary grinders by removing contaminants early, thus reducing excessive wear and tear.

Ultimately, efficient execution of these operations ensures that the investment in waste-sizing equipment, fuel, and labor is justified by the benefits. The GrinderCrusherScreen team is proud to offer its expertise in helping you find that balance.

See our current inventory of Low-Speed Shredders, Horizontal Grinders, and Tub Grinders