2012 June 01, 09:00 GMT
With energy always a high cost on any plant balance sheet, engineers need to extract the maximum efficiency from the power they pump into their machinery. One way to enhance energy efficiency is by selecting the right drive belt, says Phil Burge, Country Communication Manager for SKF.
Component technology across industry is constantly being refined to enhance performance and boost efficiency, and belt drives are no exception. Though they may appear to be relatively simple components that are common in the engineering workplace and unlikely to differ greatly from one brand to another, the truth is that beneath the surface, belts have undergone significant changes in recent years and are worthy of closer examination from any operator who wishes to optimise their equipment and extract the maximum effort from the power ploughed into belt driven machinery.
There are inherent losses with any drive but with today’s most advanced belts the energy loss is minimal; for example, there are now some exceptionally robust belts on the market that can deliver up to 97% efficiency. Such belts enable operators to maximise equipment and make a marked difference to plant productivity, especially within aggressive environments and demanding, stop-start applications.
Synchronous or timing belts offer strong potential to deliver accurate, powerful transmission. These toothed belts synchronise with toothed pulleys to enable high torque drive and the best of the current crop are constructed in highly resilient polyurethane with steel cords to deliver high levels of efficiency and performance.
Chain drives offer the ability to deliver high power even when dealing with heavy loads and come specified for many demanding applications. Corrosion-resistant coatings for drive chains provide robust protection in the extreme conditions in which these heavy duty components are frequently found, while extra strength models are available to cope with higher shock loads. Engineers can also cut maintenance costs by specifying chains that require no lubrication.
However, it is not only within the most extreme conditions that we have seen improvements in belt performance; V or wedge belts, have also undergone some significant enhancements that have enabled operators to seriously cut their costs. SKF recently brought such cost savings to Belgian zinc recycler Rezinal via a belt upgrade. Previously, Rezinal were replacing belts at the unacceptable rate of approximately once every two months, which was causing unplanned downtime and mounting maintenance costs. By recommending SKF Xtra Power Belts, we were able to extend the gap between belt replacements to more than ten times that demanded by the previous components to deliver two years’ service.
So, why do high quality belts such as SKF Xtra Power Belts provide such robust, reliable service? One explanation lies in the ability to resist common faults; for example, polyester-coated internal tension members reduce problems of elongation and incorrect tensioning. These features, plus the addition of abrasion-resistant cover fabric, reduces pulley groove wear, which occurs when an incorrectly tensioned belt slips out of position and becomes hardened by friction heat. The hardened V belt wears the pulley groove into a U shape and this compromises power transmission efficiency when a new V belt is installed because contact between the V-shaped belt and the U-shaped pulley is significantly reduced, and can only be properly remedied by replacing the pulley. A system that allows pulley groove wear is not only inefficient energy-wise but also adds to costs, since pulleys and belts require frequent replacement. In contrast, the resistance of SKF Xtra Power Belts to the conditions described above results in an efficiency rating of up to 97%, while the extended belt lifespan also makes welcome cost savings.
Of course, components and machines are only as good as the engineers that install, maintain and operate them and today we can sidestep many potential pitfalls, and enhance the lifespan of all belts, by employing a series of tools such as belt drive calculation software to ensure the right specification is made, plus gauges that ensure accurate belt tension and drive alignment throughout the life of the machinery.
So, while drive belts are, and will remain, a familiar feature across the engineering industry, it is important to remember that there are some powerful innovations taking place beneath their deceptively simple surface. Like many other components in today’s engineering environment, drive belts have benefited from a range of improvements and the engineer who takes note of these changes and specifies the most appropriate components can reap the rewards of enhanced energy efficiency, reduced downtime and significant cost savings.
Technical article above was published in the June 2012 edition of Drives and Controls magazine.