SKF Rotary Shaft Seal range - Sealing the Deal on Optimised Sealing Ability & Seal Life
2013 August 14, 09:56 Africa
SKF, the only bearing company to also manufacture seals globally, has invested substantially in a special rotary shaft seal range that offers best-in-class quality, optimised sealing ability and wear resistance for ultimate increased seal life or mean time between failures (MTBF).
“SKF rotary shaft seals have, over the past four years, enjoyed tremendous success with leading OEM gearbox and electric motor manufacturers globally,” reports SKF Seal Platform Manager for Southern Africa, André Weyers, adding that these successes have been mirrored in South Africa. “The OEMs have done their homework and research on quality and they know what they want when it comes to reliable sealing solutions. Designed in accordance with ISO 6194 and DIN 3760 specifications, our rotary shaft seal range outperformed other top European brands during extensive independent testing. Small wonder they meet the OEMs discerning requirements on all fronts - range, quality, reliability, life span and price.”
Weyers notes a number of reasons for the company’s global success in sealing solutions. “Seals are part if our global core technologies – bearings and units, mechatronics, power transmission, condition monitoring and related engineering services. SKF is currently the fifth largest seal manufacturer worldwide and as part of our growthplan to become one of the largest international seal manufacturers, we have embarked upon an aggressive acquisition drive. This includes the proven Chigaco Rawhide (CR) brand which was successfully integrated into SKF. Our successes in sealing solutions can be further attributed to our impressive global presence. With representation in more than 130 countries and 18 seal manufacturing units around the world, we have the ability to not only supply a very wide range of superior quality seals but also to offer customers unrivalled product support.”
“Maintaining sealing integrityis vital to preventingequipment failurewhichcan cause serious harm to the environment, operators and manufacturing processes,”continues Weyers.
“The quality of a seal is directly related to the quality of the seal material. Here, overall lip design, operating conditions such temperature and pressures, as well as correct seal selection all play a vital role in seal performance”
With the development of two new optimised seal material compounds, nitrile (NBR) and Viton FKM, SKF effectively addressed the wearing of the seal lip by optimising the spring tension and lip flex. Although we have no control over shaft surface finishes it remains a vital aspect that can significantly reduce the lifespan of a seal and lead to premature failure. In addition to offering higher wear resistance, NBR and FKM are ideally suited to adverse i.e. hot and/or wet environments.
The rubber outside diameter of the SKF rotary shaft seal provides optimised sealing ability in the housing as well as considerable surface roughness. The nitrile rubber compound features good resistance to ageing, excellent compatibility to synthetic oils, good pumping ability and wear resistance. “For applications with temperatures beyond the limits of nitrile rubber, we recommend FKM,” adds Weyers.
Additional features of the SKF rotary shaft range include a spring loaded and trimmed sealing lip which contributes to a quick response to handle dynamic run-out and to maintain the sealing ability. The well balanced sealing lip and flex section achieve good shaft follow-ability to withstand high dynamic run-out and shaft-to-bore misalignment.A beaded outside diameter provides an improved sealing ability and a secure retention in the bore. It also prevents spring back during assembly. The secondary sealing lip is designed with zero lip/shaft interference to create additional friction resulting in heat generation and energy loss.
Featuring one design across the range, SKF rotary shaft seals are successfully used in coaxial, worm geared, right angled, parallel shaft, input and output shaft motors, but Weyers also points out that the seal range is not limited to gearboxes and electric motors. “They can be and are used successfully in any rotating equipment application. Our two year growth plan has been so successful that we will soon be extending the standard range, which is currently available from 6mm up to 250mm shaft diameter, up to 540mm diameter. This will enable us to offer sealing solutions to previously untapped markets and applications.”
“Equally important as the seals themselves,” says Weyers, “is the availability of stock. To optimise supply chain and keep customer downtime to an absolute minimum, we work closely with and listen to our customers’ requirements; we analyse their demand frequencies and base our stock holding around our customers’ needs and production schedules. In addition, we are able to bring our comprehensive rotary shaft seal range to our customers’ doorsteps through our countrywide network of authorised SKF distributors.”
As an internationallyrespected knowledge engineering company, sharing engineering knowledge is part of SKF’s value proposition. “Therefore our sealing solution extends far beyond just product supply. Through our solutions approach, we deliver added value by supporting our customers in selecting the correct materials to suit the particular application, and offering advice and training on correct handling, storing and installation processes.The excellent design features of our rotary shaft seals makes our seal solutions the preferred option for any customers who is serious about quality and brand awareness,” concludes Weyers.