A switch from DC to AC drives at European recycling company Govaerts Recycling of Belgium has resulted in major maintenance savings with the bonus of a dramatic cut in production noise.  The new high-tech extrusion lines have at their heart modular Unidrive SPMA drives from Control Techniques.

With five production lines, Govaerts Recycling, based in Alken, has an annual output of around 8,000 tons of high quality plastic and rubber products – for street and park furniture, decking and flooring for instance.  When the company’s five DC driven production lines were facing the need of refurbishment, owner Eddy Govaerts couldn’t find suitable replacements, so set out to build his own extrusion lines.

Granules of polyofines are blown into the weigh and mixing section, mixed with colouring pigments and other additives to give the mechanical qualities required.  This is extruded at 200ËšC and injected into special moulds.  Each extruder has 12 moulds.  The moulds are water-cooled , the profiles are ejected and, after about 48 hours, are cut to length to produce a wide range of 100% recyclable products for the street, park or garden.

“Our first extruder lines had DC motors and drives,” says Eddy Govaerts.  “We bought an off-the-shelf extruder in 1996 to make our first planks and boards for horse stables, but it wasn’t very successful, required many modifications and proved very unreliable.  With our wealth of in-house experience in mechanical engineering and automation, we decided to make our own, with huge success.  For each part of the operation we found the very best components on the market and worked closely with our suppliers, who we consider technology partners.

“This policy continued when we decided to switch from DC to AC for two reasons.  From our existing extruders, we learnt that most of the maintenance was in the motors and the belts.  But we also wanted to improve the overall efficiency of the complete drive assembly – motor, belts, couplings and gearbox.  By switching to direct AC drive, a lot of this could be eliminated,” he says.

To keep the motor / gearbox assembly as compact as possible, Govaerts Recycling opted for an original concept, whereby four 37kW water-cooled AC motors are all direct-connected to the shaft of the gearbox, effectively giving total power of 148kW, but with a total size only 25% of before, eliminating drive belts and improving overall efficiency by 10%! 
 

This new assembly is completely maintenance free, with no belts or couplings to fail, no air filters, no lubrication required and, what’s more, completely safe, so no protection covers are required, cutting build costs.>>>>>>>>