Electric preshredder offers advantages to auto shredder operator

Buffalo, New York-based Wendt Corp., the U.S. distributor for MTB Recycling of France, sold an EZR Pre-Shredder to Rochester Iron and Metal, Rochester, Indiana, in 2021 that features shrink discs made by MAV S.p.A.

The scrap metal processor worked with Wendt to install a 60-inch automobile shredder in 2012. After that machine had an incident with an unshreddable in 2018, causing multiple days of downtime, Rochester Iron & Metals President Jason Grube has said he decided to make some changes to the way the business operates, including the installation of the EZR Pre-Shredder.

The preshredder uses low-speed, high-torque technology to homogenize hammermill feedstock, allowing the primary shredder to achieve full-box shredding, increasing tons per hour while decreasing the wear on castings, according to Wendt. Operators also have the ability to catch and remove unshreddables prior to the material going to the primary shredder, reducing the chance for catastrophic failure. They also can puncture explosive containers without creating an ignition source, helping to reduce the number of explosions in the hammermill shredder, the supplier says. 

In addition to these benefits, the EZR offers energy efficiency by using synchronous high-torque electric motors that feature shrink discs made by Italy-based MAV, a product line of Fenner Drives.

The MAV 3208 shrink discs, which are mounted on the extraction and feeding rotors, helped to achieve electrification of the unit. The shrink discs connect the gearbox’s hub to the rotor’s shaft, allowing MTB to use gearboxes with hollow, low-speed shafts and a compact design, saving weight and space in the EZR.

The MAV shrink discs have a clearance-fit mounting and require no keyway making, them easier to install and remove, according to the company. In addition, the high contact pressure between the parts creates a stronger connection and a longer useful lifetime, especially in applications like shredders, with shock or reversing loads. It also eliminates fretting corrosion.

Previous generations of preshredders relied on hydraulics because of the large amount of power required, MAV says. In addition, the electric units have a smaller footprint and are less complex than hydraulic models.

“We are basically going to become an 80-inch mill without the installation costs,” Dan Zeiger, controller for Rochester Iron and Metal, said when the addition of the preshredder was announced. “From a financial perspective, the payback estimations are in months, not years.”