A cut above

Written by: Steed Webzell | Published:
Blue Group Doppstadt AK 560 Eco Power

Steed Webzell reviews some of the recent and most eye-catching market entrants in the world of mobile shredding technology, discovering a multitude of useful innovations for waste management professionals from companies spanning UNTHA, Terex, Hammel, Doppstadt, Bomatic and AXO

As the well-recited phrase goes, if the mountain won’t come to Muhammad then Muhammad must go to the mountain. Alright, so in this instance the mountain is a veritable pile of waste that needs to be shredded, but even so, the sentiment supports the reason why there is ongoing demand for mobile shredding machinery, and why the developers of this technology continue to evolve their designs.

A case in point can be seen at UNTHA, which has recently launched what it claims is the world’s first electrically driven mobile shredder. The XR mobil-e is said to be the first machine of its kind to shred with a low-power electric drive and, thanks to its on-board auxiliary power pack, can be easily moved around a production facility and plugged back into the power supply. Importantly, the XR mobil-e can process a variety of materials, including household rubbish, construction and industry waste, demolition waste, wood and other bulky wastes, to produce a wide number of fuels for the waste-to-energy, cement, gasifier and biomass markets.

A series of interchangeable screens and cutters are available that enable the shredder to be configured according to the output specification, with homogenous particles of 30-400mm achievable.

The electro-mechanical – rather than diesel-hydraulic – drive reduces the fire risk and hence insurance premiums, while further benefits of UNTHA’s electric mobile shredding technology include no fuel emissions, noise levels as low as 80dB(A), and the absence of pulleys and drive belts to help minimise maintenance requirements.

“The XR mobil-e is the result of a nine-month engineering project that concluded with trials in Austria and Germany,” says Peter Streinik, UNTHA’s head of business unit waste. “These trials revealed throughputs as high as 70 tonnes per hour, foreign object removal in minutes and machine reconfiguration to handle different material streams in as little as two hours.”

Of course, the latest mobile shredding technology is aimed at forward-thinking waste management companies that want to start producing alternative fuels from the valuable resources they process, as well as existing alternative fuel producers who want to increase their throughputs, reduce operating costs and achieve plant flexibility by investing in just one, moveable capital asset.

Terex TDS V20

With this in mind, another new shredder offering something a little different is the Terex TDS V20 medium speed model.

Available in the UK from Warwick Ward, the double-shaft shredder chamber has been developed by Vecoplan specifically for the mobile industry. It benefits from an independent hydrostatic drive and 8m³ product sizing screens. This screen system, which is available in different sizes, comes complete with an intelligent protection system, allowing a desired particle size to be produced while still being able to cope with foreign objects.

The TDS V20’s ability to produce a controlled product size in one pass is of benefit to the user as it saves both time and fuel.

It can shred materials such as wood waste, green waste, domestic and industrial waste, and is particularly suited to producing refuse-derived fuel.

So, what of the technology behind the performance? Well, the shredding unit itself features a pair of 630mm-diameter shafts measuring 2,000mm in length, served by a tilting feeder. Inside, the bolt-on, aggressive cutting teeth can be rotated in order to maximise the life of parts. Driving the shredding unit is a choice of Scania engines, either a DC13 Tier 4 Final (368kW) or Scania DC13 Tier 3 (371kW).

Hammel VB 1500DK

Stepping up another notch altogether in terms of size and capacity is the recently introduced Hammel VB 1500DK, which is possibly the world’s largest mobile shredder. This monster of a machine houses two Caterpillar C18 Diesel IV interim engines, producing an eye-watering 1,119kW of power and 1 million Nm of torque at a maximum 1,900 rpm.

A two-sided transmission drives the bespoke intertwining shafts, with material handling achieved via a pair of individually controlled tilting infeed hoppers. Needless to say, with power output and torque on these levels, applications include car bodies, engine blocks and aircraft wrecks.

Further R&D efforts at Hammel can be seen with the recent introduction of a pair of Alligator shafts optimised for the processing of different wood types.

With an end size material of 0-150mm, the company is able to achieve throughput of 20-25 tonnes/hour using the new shafts in a Hammel VB 750D shredder. The shafts are also said to be applicable for the processing of municipal and industrial waste.

Doppstadt AK 560

Retaining the topic of recycling organic waste, Doppstadt says its latest AK 560 Eco Power and AK 560 Eco Power Plus models not only achieve a higher capacity in a shorter time, but consume less energy and fuel than the previous models. Serial production of the machines began in January, with UK availability from Blue Group.

“The mobile machines are designed for continuous operation in the field of recycling,” says product manager Thomas Diekmann. “With their high throughput capacity and load-sensing material infeed they are suitable for waste wood, wooden pallets, green waste, logs, root timber, bio-waste and RDF.”

Eco Power shredders seize the material at the impact edge and then reduce it at a baffle plate equipped with Hardox teeth, or with a replaceable cutter bar. The operator determines the final material structure and grain size using the fine shredding basket in the discharge area of the shredding chamber.

For different materials and shredding structures there are baskets available from 30-400mm mesh size. Doppstadt says they can be replaced in a few minutes without tools and, since they are driven hydraulically, do not collect contaminants.

A Mercedes-Benz MTU diesel engine 6R1300 drives the whole unit and complies with Tier 4 Final without the need for a diesel particulate filter.

The engine, which offers 2,000rpm working speed and 390kW power, is said to achieve high torque thanks to the electronic engine management system. Furthermore, the new automatic tensioning mechanism eliminates the requirement for frequent, manual tensioning of the power belt, reducing maintenance demands on the machine.

Quick-change, free-swinging Dopp-Lock shredding tools can be replaced in a matter of minutes, while a new long-life baffle plate helps ensure operating longevity, even when shredding contaminated input material.

To waste industry professionals, shredding clearly brings to mind a whole spectrum of equipment and, nowadays, a whole host of new technologies to consider.

Static but emphatic

With regard to static shredding machines, recent innovations include the Bomatic Rotacrex R750, R1200 and R1600 models that are available in the UK from Fercell. Unlike the majority of Bomatic shredders, which use knives and blades to cut material, the principle of operation of the R series is impaction, and as such is virtually unaffected by foreign materials.

Repeated contact with the rotating impact tools subjects the process material to centrifugal forces which collide feed material both against itself (accounting for approximately 80% of reduction) and the chamber impact plates. Featuring eight steel impact blades, it is claimed that “any material is shattered within seconds”. This vertical-shredding technology is certainly a radical departure from the conventional shredder design of horizontal single-, two- or four-shaft technology.

With dimensions of up to 1.6m in diameter and output up to 20 tonnes/hour (material-dependent), the Rotacrex shredder series features impact blades which are specially toughened and use anti-shock mountings. The shredder crushes industrial materials such as electronic scrap, wire, metal and toner cartridges, as well as more unusual inputs such as abattoir waste (including bones), automotive plastics and catalytic convertors.

Another interesting static shredder innovation can be seen with AXO’s Fatso range, specifically HH series shredders, which indicates hard-drive specific models with replaceable concave Hard-Heads.

The Hard-Head system was said to have been developed by Bedfordshire-based AXO to lower the cost of shredder ownership.

The Hard-Heads are attached to each cutter, fixed from the rear with

a cap-screw. Because of this

they can only be fitted to cutter widths above 20mm.

The Hard-Heads can be removed and rotated after the leading edge has worn. In fact, according to AXO, they can be replaced while the cutter shafts are still in the shredder block.

As a point of note, the Hard-Head material and treatment process is specifically developed for AXO to increase cutter life and reduce overall wear cost.

Hard-Heads have a convex face with sharp points, so they keep the shredder grabbing and pulling in more material for a longer time, says AXO.

This makes them suitable for hard-to-grab applications such as plastics, drums and paper roll cores.

Higher-wear applications such as paper pre-shredding, biomass and multistream waste are also targeted by this technology.


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