A ZZ Power Zerdirator – the biggest and most powerful shredder in the Lindemann range – has been installed and commissioned at S. Norton’s scrap metal recycling facility in Manchester, UK. The ZZ Series shredders are renowned for their high throughput capacities paired with low specific energy requirements – which support profit maximization for operators. The system can now process up to 130 tons of recycled metal an hour.
The all-new processing line is part of a £20 million investment by S. Norton, which also includes an EtaRip pre-shredder from Lindemann. Thanks to much greater throughput than the line it replaces, the new shredders increase the company’s capacity to process waste metals. It also produces higher quality ferrous and non-ferrous scrap metals, and significantly increases the company’s capacity for processing waste electrical and electronic equipment (WEEE). The plant went live in October and is now fully operational.
Variable frequency drive
The centrepiece of S. Norton’s new scrap processing line is its 3,000 hp Lindemann ZZ Power Zerdirator shredder, which is one of the most efficient in the world. It is fitted with the optional Shredder Drive Assistant (SDA), which supports the feeding process and optimizes the utilization of the shredder capacity – and is the first shredder of-its-kind to be fitted with Lindemann’s sophisticated Variable Frequency Drive (VFD) system. Exclusively developed in partnership with Mitsubishi Electric, VFD is a medium voltage system that ensures the shredder drive remains highly consistent, thanks to the integration of low maintenance frequency inverters on three phase asynchronous motors.
VFD: how it works
The rotor in a shredder must cope with constantly changing performance demands, due to the intermittent nature of material feeding into the machine. When the shredder rotor is loaded with scrap metal to process, the rotor speed briefly decreases. The motor then tries to quickly accelerate the large and heavy rotor back to its normal speed. This constant change between slowing down and speeding up of the shredder rotor places high demands on the motor. The efficiency of shredder operation is therefore largely determined by the quality of motor load monitoring and speed control. The aim is to return to the normal motor speed as quickly as possible – and this is where VFD excels, resulting in energy savings of up to 30%
‘Do the job once – and do it right’
Founded in Liverpool in 1962, S. Norton Group collects, processes and distributes approximately 1.5m tons of recycled metals each year. It also recycles more than 95% of all materials it processes via shredding, with a target of sending zero waste to landfill.
“We have always believed that we should do the job once – and do it right,” said David Hobson, Group Capital Projects Manager for S. Norton. “We've got a strong relationship with Lindemann, and have done for decades. They have supported us all the way through this project.”
“Working on this project with S. Norton has been a very challenging but also very rewarding experience,” agrees Lindemann’s project manager Manuel Eickhorn. “The excellent collaboration and working as a team with our customer have ultimately made this project a success for both of us.”
When asked why the VFD option was chosen on the ZZ Power Zerdirator he said: “The main reason is the improvement in performance. It gives us complete control over the rotor speeds, which is something which we've never been able to do previously. Then there is the energy efficiency savings. Finally, in comparison with our previous shredder’s drivetrain the VFD is very simple and low maintenance – almost a direct coupling into the rotor.”
“This all-new installation represents the best-in-class for shredders worldwide,” said Nikolas Sachinopoulos, UK general manager Lindemann. “It’s also a great advertisement for the significant advantages offered by the variable frequency drive’s motor load monitoring and speed control systems. We are pleased that our relationship with S. Norton – which already dates back more than 40 years – is set to extend well into the future, thanks to this new installation.”
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