Moving Materials with a Sustainable Focus

Moving Materials with a Sustainable focus

Products like low-friction bearings can extend the life of conveyors and lifts and help to boost sustainability in the material handling sector, says Jerome Pommereul, Global Business Engineer at SKF.

The climate meeting in  Paris proved that politicians are capable of coming to agreement  on important issues. While they can   be commended   for their diplomatic skills, the hard work of implementing environmental targets will largely be down to industry.

SKF’s Director of Corporate Sustainability, Rob  Jenkinson,  recently said that industry will need to Roll up its sleeves and plot a way forward in putting these commitments into practice. This needs to begin straight away, by investing in lower- carbon technologies and addressing specific sustainability needs

The materials handling sector encompasses everything from elevators in skyscrapers, cranes, light conveyors (like baggage handling lines)  and conveyors in mines.  Each part of  the industry is very different but has similar underlying sustainability concerns – such as boosting energy efficiency, extending service life and lubricant disposal.

grease disposal

At one time, lubrication grease was simply disposed of but now it must be recycled. This, however, is not so easy to achieve. For this reason, there is a concerted effort to cut the use of grease in applications such as lifts, conveyor pulleys, and cranes. Less grease  means less  disposal, which ultimately means less pollution.

One solution  is to use bearings  that do not need  re-lubrication. In bearings with solid oil, the lubricating  oil leaves the oil saturated    polymer material onto the bearing raceways. The part is then lubricated for life – which has the added advantage of cutting the need for maintenance operations.

In the   heavy conveyor’s application, another popular way to solve the problem is to use a ‘three barriers’ solution. The solution consists of: a housing with a   seal,  a  sealed bearing, and grease   filled in the space between the bearing and the housing seal. The solution has environmental benefits since the use of grease is significantly lower because you no longer need to purge the bearing clean with grease. The bearing itself needs small quantities  of grease to function.    Furthermore,  the bearing life is significantly   improved because it is working in a protected and clean environment. In a conveyor pulley, this means that the life of the bearing system is longer or equal to the lagging on the pulley thus no longer a bottleneck.

Added efficiency

A far more pressing concern is energy efficiency – as it is for many sectors. Elevator manufacturer KONE estimates that up to 10% of a building’s energy consumption comes from the elevators, which makes it a key target for efficiency gains. There are already ways of clawing back some of this energy, through regenerative drives for example, or through traffic analysis optimizing the flow of people and number of elevators.

The move   towards more   sustainable and energy efficient products  in lifts and elevators is partly accounted for by the strict LEED certification required for new building. This informs everything from building materials to construction methods. Regarding lifts, customers can specify the type of system they want and there is a definite trend in that they are increasingly demanding ones with higher standards of efficiency.

A third and crucial element of sustainability is to extend the working life of a product and its components. Every time you scrap a component, you are not just throwing away the material it is made from – but all its embedded energy and carbon all the way back up the value chain. For this reason,  lengthening lifecycle is of huge benefit.

Within material  handling, many lift  manufacturers now insist that components last the life of the product. This can be achieved by specifying low- friction bearings – such as SKF Explorer bearings.

SKF  recently introduced a  new range of small, sealed SKF Explorer spherical roller bearings that can prolong – or even eliminate – service intervals. Fitted with a gearless traction motor in a heavy-duty elevator, it lowers energy consumption by around 145kWh per year – equating to a CO2 emission saving of two tons over the motor’s  life cycle.  These cut friction by as much as 20%, with a subsequent up to 20 degrees Celsius reduction in working temperature, extending bearing life to match that of the lift system itself. This helps   deliver the   ‘maintenance- free’ regime that is important to lift manufacturers. The sealed SKF Explorer spherical roller bearings form part of SKF’s Beyond Zero portfolio of products, which are designed to impart real sustainable benefits in their applications.

There are   many examples   of how sealed bearings extend the service life of elevators: one Asian elevator manufacturer switched its entire production to sealed SKF Explorer spherical roller bearings, as a low- maintenance solution that would last for at least 20 years.Similarly, a European elevator  manufacturer  used  them  with  adapter  sleeves  when it needed a quickly mountable bearing on its first high-rise gearless traction machine

Handling Baggage

There is no particular sector within material handling  that leads  the way on embracing  sustainability.  Rather, there are individual companies that are taking the lead. A good example of this is Vanderlande, which has designed a baggage handling system using a ‘Cradle to Cradle’ (C2C) approach. It is an excellent illustration of a company developing a product with sustainability in mind.

Its ‘Blueveyor’ system – which has been running at Amsterdam’s Schiphol Airport since June 2014, consumes around half the energy of a conventional baggage system.  C2C  principles require the product to be fully recyclable at the end of its life, meaning that SKF had to adapt its Y-bearing unit slightly to accommodate this. It meant removing all polymer from inside the seal and lubricating the bearing with biodegradable grease.

The bearings are used in belt conveyors on the handling line, with four used on each conveyor.Vanderlande specified the C2C guidelines to SKF, which was then responsible for developing the bearing solution based  on this  approach.  The two companies have worked together extensively in the past,  and  SKF  has a similarly progressive attitude to sustainability as Vanderlande.

Engineers love a challenge and there is none greater than helping to protect the planet and create a more sustainable future for all.  Ultimately it is the  role of engineers in projects like those demonstrated earlier, that will be crucial in helping to arrest the effects of climate change. 

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