What started out as a simple bearing selection turned into a complete shaft redesign, manufacture and assembly for leading South African small-sized mill OEM, Energy and Densification Systems (Pty) Ltd. (EDS), thanks to the combination of SKF’s competent Project Engineering team and the company’s quality turnkey product portfolio.
When EDS, who owns the proprietary design for a new small-sized material processing mill concept, started experiencing contamination ingress and premature failure on their beatings and Jaw couplings, they decided to approach bearing and rotating specialist, SKF, for a solution.
The design of the compact, multi-shaft, vertical mill, which has the capability of processing various materials, features a few horizontal shafts with strengthened flinger attachments that agitate the product as it passes through the mill. The milling action combines several processes such as crushing, milling, densifying, blending and attrition to provide an output product that will coincide with various specifications within a variety of applications in sectors such as mining, energy, steel manufacture, waste reprocessing, environmental rehabilitation, agriculture as well as general milling.
The SKF Project Engineering team donned its collective thinking cap to find the best solution for EDS. “We proposed a complete redesign of the entire shaft assembly which includes bearing selection, improved seals as well as a new housing design,” explains SKF Application Engineer, Cody Petersen.
The new shaft assembly incorporates SKF’s superior, case-hardened spherical roller bearings. “We selected these particular bearings given their special design which is highly suited for high vibration and shock loading applications,” notes Petersen. “The locally manufactured shaft and housings were machined, and quality controlled by SKF to ensure that our bearings reach their intended lifespan.”
The improved sealing solution included the addition of an internal double lip seal as well as an improved labyrinth seal design incorporating a special cup and O-ring system that provides dynamic sealing against contaminant ingress and prevents lubricant loss.
The complete scope of work by SKF on a total of ten shafts, including one spare, comprised of 22 bearings, 22 rotating and 22 stationary labyrinth seals, 11 clamping rings, 33 radial shaft seals and 10 non-drive end and 10 drive end housings. “We also proposed to our customer a complete SKF grid coupling which is more forgiving and better suited to the milling speed than the existing couplings that were on the shafts,” adds Petersen.
SKF’s all-inclusive solution which showcases the company’s full basket of premium brand products, increased reliability on the customer’s design, improved supply chain reliability and increased turn-around time. Product and technical support from SKF Application engineering added further value for EDS.
“Proof of the project’s success in building trust with this new customer in the SKF brand as well as in the company and our Project Engineering team is evident in the fact that we have received an order from EDS for an additional twelve shaft assemblies,” concludes Petersen.
SKF’s mission is to be the undisputed leader in the bearing business. SKF offers solutions around the rotating shaft, including bearings, seals, lubrication, condition monitoring and maintenance services. SKF is represented in more than 130 countries and has around 17,000 distributor locations worldwide. Annual sales in 2019 were SEK 86 013 million and the number of employees was 43,360. www.skf.com
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