MechChem Africa March 2017

⎪ Products and industry news ⎪

Surface aerator impeller vanes are used to pull wastewater up from the tank and discharge it horizontally outside of the impeller rim. Air and oxygen are continuously mixed, dissolved and circulated through the wastewater being treated. Inset: a layout diagram of the Meyerton aeration systems.

DINmotor specifications, which is among the most rigorous of quality standards. Other key features include a compact andmodular design, making thesemotors exceptionally easy to couple to both new and legacy SEW-Eurodrive gearboxes. “We have local stock holding and service capability and the range covers applica- tions all the way from 0.75 to 315 kW in voltages from 240 to 690 Vac,” he adds. While the DRN range has been launchedwith competitive pricing in com- parison to competing premium efficiency alternatives, the real price advantage, according to Swanepoel, comes because of the ability to quote the complete drive- train systems, including any SEWgearbox, DRN motors and, where required, SEW VSDs too. A whole system price can be significantly less expensive than a solu- tion involving several different suppliers,” he notes. SEW is increasingly moving towards offering holistic solutions: “Take a ball mill in the minerals processing sector, for example. We can supply the drive gearbox from our X-series industrial gear unit range, a DRN motor with a VSD to control the speed.We cannowalso supply the girth gear, itself, so the design, instal- lation, servicing and maintenance of an entire mill drive system can be supplied from SEW-Eurodrive as a single-source solution,” Swanepoel points out. Returning to the additional customisa- tion work for these aerator systems, he says that the units also had to be custom- ised with instrumentation specified by the client. Oil flow switches were fitted to manage the lubrication pumps. “The MC range is fittedwith amechanical shaft-end

biological activationprocess and toomuch is a waste of energy,” he says. Reducing energy consumption is the key reason for choosing the newDRN IE3 motors for this application. “This is thefirst supply of these motors into a big project in South Africa. These are IE3, premium efficiency asynchronous motors, which offer energy efficiency advantages over previous-generation standard efficiency (IE2)motors,whicharebeingphasedoutin many parts of theworld,” says Swanepoel. In the European Union (EU), all two-, four- and six-pole asynchronous motors with power ratings of 7.5 to 375 kWmust now meet the requirements of the IE3 energy-efficiency class. “While South Africa does not face the same regulatory pressure, we have decided to raise the benchmark bymaking theDRN series our standard offering here too,” he points out. The single source advantage “Having long been one of the preferred gearbox suppliers for mixing and aeration applications in thewater industry, our abil- ity to couple our gearboxes with our own premium efficiency motors means that there is no longer a need to have multiple suppliers and warranties to cover the drive-end of these systems,” Swanepoel suggests. “We can nowsupply complete systems with a single warranty and a common ser- vice agreement – all because of our new DRNmotor offering,” he tells . By meeting the IE3 efficiency stan- dards, customers can be assured that these motors are as efficient as any pre- miumefficiencymotorsmadeanywhere in theworld, and theyalsocomply toGerman

pump that is mounted underneath the gearboxtocirculatetheoilbackup.”Hence the reason for fitting the flow switches. These are necessary because the boxes are hanging vertically, so the oil has to be circulated back up to the top bearing. Splash lubrication is inadequate in these situations. The motors were fitted with high accuracy PT100 temperature sensors, which send temperature data back to the controller for continuous temperature monitoring; and thermostat-basedmotor protection that cuts out internally when dangerously high temperatures are being experienced. “Strip anti-condensation heaters were also incorporated to protect the motors from damp, along with rain canopies to protect the systems from theworst of the weather. All of theequipmentbeingusedis IP65 rated–100%protectionagainst dust ingress and low pressure sprayed water.” “We succeeded in meeting all the de- livery dates andwe nowhave the common stock in South Africa, so going forward, we will be able to customise any motors with these additional features here in South Africa. Concluding, Swanepoel says that SEW- Eurodrive’s mixer, agitator and aerator systems’ offering is now much stronger. “From a quotation and selection point of view, we doour own calculations basedon any client application and recommend an optimumdrive solution – one that is com- petitively priced with a single warranty from a single service provider. “We offer German quality solutions at lifecycle costs that will be difficult to beat,” he says. q

March 2017 • MechChem Africa ¦ 37