Without question, the shredder plays a central role in the ever-evolving business of recycling and waste management, not only for processing metals, ELVs and tires but also for size reduction of an increasingly wide range of materials. The latest models easily handle everything from plastics and fibre, e-waste and ASR (auto shredder residue) to organics and biomass, as well as C&D debris and solid waste for refuse-derived fuel (RDF) applications.
In contrast to large, stationary shredders designed to process mostly homogenous materials such as ferrous metal, today's multi-material mobile units (1,000 to 4,000 hp models, or even smaller) in particular have become more and more common.
Mobile shredders (mounted on tracks, trailer- or skid-mounted) are most commonly available in dual-shaft (or twin-shaft) configurations, as well as in single-shaft. Units can run at slow- or high-speeds, and are available with hydraulic, electric or hybrid drives, or with Tier 4 diesel engines and alternative fuel options. The latest offerings are designed to provide longer-lasting wear parts, ease of maintenance, much improved noise and dust reduction technology, high levels of safety for operators and the ability to produce very specific output at high capacity.
With so many variables involved when a recycler is thinking about how best to integrate a shredder into their operation, we asked three established manufacturers - Lindner America, Terex Ecotec and Shred-Tech - to provide some insight on the development of their latest mobile models, trends in the sector and what to think about when considering a purchase.
The Evolving Shredder
Jonathan Gilmour, with Terex Ecotec, says that during the last ten years there has been a much greater focus placed upon sustainability and environmental awareness in all industries, which has been part of the driving force behind the evolution of shredders.
"Recognizing the untapped potential contained in waste, many processors have started to change their approach to dealing with it," he says. "The increase in RDF demand and biomass-fuelled power plants, for example, has opened up outlets for waste which would otherwise be landfilled. With this in mind, Terex Ecotec has developed a range of mobile machinery that is equipped for this change of attitude."
Gilmour says the Terex Ecotec TDS V20 medium-speed shredder, as an example, is able to produce a finished RDF or biomass product in a single pass while protecting itself from damage caused by contamination. "Using cutting knives and a sizing screen, this machine creates a uniform product that contains minimal fines."
According to Lindner America president Andreas Schwarz, Austria-based Lindner-Recyclingtech GmbH introduced the first recycling shredders to the marketplace about 30 years ago.
"Even though we delivered industrial heavy-duty built machines that would last decades, it became apparent that serviceability and safety needed to be the focus for our future generations of shredders," he says. "Lindner has developed stationary and mobile shredding machines that are particularly suitable for RDF, plastics and biomass applications, each one being distinctly different and optimized to minimize the cost-per-ton operating expense, while making the machines safe and easy to maintain."
Schwarz adds that the technology has evolved mostly into specialized machines for particular applications. "Shredders are sometimes thought of as ‘one size fits all' but that is definitely not the case," he says.
Chris Howard, GM of operations for Lindner America, emphasizes that Lindner is very much an R&D and engineering company that manufactures everything in-house, with a focus on very high-end machines. "We work closely with the customer to determine what their needs are, what they are looking for in terms of output, and match machines to those needs," he says.
"Lindner offers several models of mobile shredders, both in the fully mobile category (track machines controlled by remote) as well as machines designed to be easily moved with our customer's equipment. Howard adds that all Urraco models have Tier 4-compliant motors, to over 700-hp, are designed to meet mid- to large-volume needs and feature multiple shaft options, as well as a double tilting hopper system and control system that monitors input feed rate to optimize throughput along with consistency in material output. "These models also feature software controls that automatically sense the torque load in the hopper and forward/reverse the drive shafts to continually maintain operation and output," he says.
Lindner's Urraco 95 model is a primary, mobile, two-shaft shredder designed with a powerful engine, long working length and aggressive input. Units provide high throughput and low fuel consumption, powerful hydraulics, and a heavy, remote-controlled track system with two speeds and intuitive joystick controls.
"Multi-material shredders is a very good way to describe our line of mobile machines," says Howard. "There are not a lot of limitations with the Urraco. It can handle a very broad range of materials, from railroad ties to metal, produces a high-quality finished product and is a leader with respect to market share in Europe, especially in RDF applications."
Based out of Ontario, Shred-Tech is a manufacturer of twin-shaft shredders - mainly smaller to mid-sized stationary machines used in metal recycling and for secondary applications requiring precision cutting, or in cases where a finer, controlled output is required.
In May of 2016, Shred-Tech began a distribution partnership with HAAS, the Germany-based manufacturer of high-volume, primary mobile shredders designed for applications in MSW, C&D and metals, as well as biomass and RDF shredding. Shred-Tech is now the exclusive distributor for HAAS in North America and Australia.
Sean Richter, Shred-Tech's sales manager, shredding and recycling systems, admits that it is tough to put a finger on monumental changes that have occurred in the shredding industry over the last several decades, but that it has been more of an evolution of advancements in small increments.
"There has been a lot of changes in terms of knife design, in cutting chamber design, allowing users to have specific knives for specific applications," he explains. "And there have been a lot of changes in drive applications. Shredders are not simply just electric- or hydraulic-drive any more. We also have DC servo drives, where we can get feedback from a processing line, we can match the speed of material coming off the line, and shred at a certain rate. We can also stop shredders (dead positive) and start up in forward motion, with full torque. This is done using DC drives rather than traditional AC drives."
The German-made HAAS Tyron mobile shredder is available with 1,500-, 2,000- and 2,500-mm length chambers, with horsepower ranging from 350 to over 770, and is available in static or mobile configurations, tracked, trailer-mounted or skid-mounted.
Richter says Haas twin-shaft shredders are unique because the shafts are independently driven in terms of rotational speed, rotational direction and the time sequence that they spend in either forward or reverse.
"The cutting chamber is constantly self-cleaning with the forward/reverse tearing action of different rotational speeds," he continues. "This feature allows them to process a very wide range of feedstock and prevents materials like fabrics, plastics and wire from wrapping on the shafts."