SKF focuses on solutions for rotating conveyor applications such as head and tail pulleys, bend and take-up pulleys, as well as idlers. The solutions entail bearings and housings, lubrication systems and lubricants, seals and condition monitoring. Jonas Kjellberg, Segment Manager, Global Material Handling Segment, spoke to Milton D'Silva, Editor, Industrial Products Finder, about the company's products for this segment. Excerpts:

While conveyors move materials, what about the elements that keep the conveyors moving? What are the SKF products for this application?

SKF offers a wide range of bearings for conveyors, and not just the bearings but related products that today form the five platforms of the company: Bearings and Units; Seals; Lubrication Systems; Mechatronics; and Services.

From small precision products in dust-free cleanrooms to the dusty environment of mines and construction sites, conveyors come in a wide size range. What are the solutions on offer?

SKF bearings come in a wide size range to match the application, depending on the load and the operating environment. Conveyors operate in clean as well as harsh environments and there are many different ways to enable trouble free service.

Lubrication is often a weak link in the complex mechanism of the conveyor systems. How effective is the lubrication system?

Firstly, there are sealed bearings that are pre-lubricated at the factory and in most cases no other lubrication is required when using sealed bearings. For lubricated bearings, there are two ways for lubrication - manual and automated. In the manual system, one has to actually reach the hub and lubricate it. In the long run this is not an effective system. Then there are automatic lubricators, pre-engineered lubrication systems and the centralised lubrication system. In centralised lubrication, the system is almost maintenance free, with only the reservoir needing to be topped up with the lubricant and an occasional visual inspection.

For harsh operating environments, SKF offers the three-barrier solution, which is a combination of the integral bearing seal, the housing seal and the housing grease that fills in between these two and acts as a contaminant barrier. The housing seal is the standard labyrinth seals and for heavy conveyors in extremely harsh environment, the taconite seal, which is even more effective. So, together, these various systems offer a very reliable solution for lubrication needs.

Is the lubrication system dependent on the human element, which again is prone to errors of over or under lubrication?

Manual lubrication involves working with tools, and this makes it even more hazardous. It has been observed that 30% of the work-related injuries occur during maintenance work, so this is a health and safety hazard. So, as far as the conveyor systems are concerned, the best thing is to avoid manual lubrication completely. The centralised lubrication system is the best option here. Some of the conveyor bearings are large diameter bearings of 600-800 mm dia and there are small central lubrication systems designed for these.

For a rugged conveyor system running across stretches, does lubrication call for a stoppage of the system and thereby halt in production?

SKF offers a number of reliable and automated solutions that work while the conveyor is operating. So there is no need to stop the system just for lubrication. But having said that, it must be noted that about one-third of the problems in conveyors are attributed to bearing related troubles or the lack of bearing maintenance. So it is very important to select the right bearing and then follow the routine maintenance schedules.

A good bearing is only half the job done. What about the housings for these bearings? Can it withstand the load and wear & tear?

For conveyors, as with other applications, SKF has a good range of bearing housings and related seals, with high load carrying capacity and excellent resistance to shock loads. The housings are easy to mount and align even out in the field. Correct tolerances are very important, which otherwise cause shaft elongation and subsequently, bearing seizure. These housings are also compatible with the various lubrication systems, manual or automatic, and condition monitoring systems. A wrong choice of housing can ruin a good bearing, and it would not be prudent to cut costs on this front as it will certainly prove to be very expensive in the long run.

Seals are another area where bearings take a beating. Would ordinary seals withstand the harsh environment of heavy conveyor loads? What are the recent trends in new materials?

The three-barrier solution mentioned earlier is a very good option when working with sealed bearings, which even otherwise prolong the life of the bearing. The combination of a standard labyrinth seal and the integral bearing seal with grease packed between the two effectively keep the contaminants out. The concept is to have grease in the right place, keep the grease in and dust/dirt out. Then, other than the standard labyrinth seal there is Taconite seal for bearings operating under very arduous conditions. Grease enhances the sealing effect, which is helpful in the presence of taconite, and therefore extends the service life of the seals.

Preventive maintenance is an important factor built into maintenance schedules today, with automation being the facilitator. What are the tools from SKF for this vital requirement?

There are many tools and systems for preventive maintenance, right from basic manual hand held instruments to completely automated processes. Basically, such tools literally enable 'listening' to the bearing and reading the correct signals, and then carry preventive maintenance work. Then there are the various condition monitoring systems, including 24/7 online and remote monitoring systems that are excellent for conveyor systems spread across long stretches. These systems work with various sensors for picking up the data, and analysers to interpret it and then indicators to read the possible problems. The data can be downloaded on regular basis for corrective action. This also minimises manual intervention in hazardous areas and enhances safety. So depending upon the criticality of applications, a suitable system may be selected.

Another tool is the SKF Client Needs Analysis, which, in combination with Asset Management (CNA-AM), uses the SKF experience in reliability-focused maintenance with the client's knowledge of plant conditions to help provide useful and actionable information to focus on improving the plant's performance.

Customers today are not merely satisfied with products. The emphasis is on solutions, and all major players are aspiring to be complete solution providers. So is SKF the one-stop-shop for all these requirements?</p>

Yes, with over 100 years of experience and a wide range of products, some of which are discussed here, SKF is certainly a one-stop-shop for the five product platforms the company is operating in: Bearings and Units; Seals; Lubrication Systems; Mechatronics; and Services. Together, these can cater to the toughest and most demanding conveyor and other applications.

Finally, it all boils down to cost. How does the cost of ownership over the life cycle compare with the competition?

The cost is not just of the product at the buying stage, but rather the cost over the lifecycle time of the product, its maintenance, servicing and realising the optimum performance. It is all about providing value to the customer. And on that front, the cost is very competitive.

How is the present business environment?

It is fairly good, can be better! Though the recovery is happening, it is not uniform across the globe. Asia, in particular China and India are doing well, and in conveyors segment the demand is a bit ahead of the market.

What are the future plans?

The company will continue to provide value to customers as a premier supplier of bearings and solutions. For heavy industrial conveyors there will be better products and solutions. The three-barrier concept can deliver huge value for customers as seen from the response from the customers who have adapted this solution of opting for sealed spherical roller bearing in place of open bearings.

Another development is the energy efficient bearings that consume up to 30% less energy. With growing awareness as well as stringent statutory requirements, use of energy efficient products is on the rise. SKF has certain edge over the competition in this area, with 50-70% less friction. So innovations will continue.

At the forthcoming CeMAT Exhibition in Mumbai, Mr Jonas Kjellberg will be holding a Conference on December 15, 2010 from 10:00-13:00 hrs, at the SKF Stall: D 101, Hall # 5, Bombay Exhibition Centre, Goregaon, Mumbai. For more information kindly contact: Ms Aparna Dahanukar, SKF India, Mumbai. Tel: 022-66337787. Email: aparna.daha nukar@skf.com