Today’s bulk conveyors are moving a more punishing mix of raw materials, into more places, than ever before. Meanwhile, at the opposite end of the scale, conveyors in food and beverage must maintain performance while offering enhanced product safety. To meet these demands, conveyor OEMs are looking for ways to optimise design, development and production to enhance industrial conveyor efficiency.
Drawing on decades of material handling experience, the designers and engineers behind the components that drive conveyors are helping OEMs to build machines that reduce the high costs of unplanned downtime, maintenance and energy, says Phil Burge, Country Communication Manager, SKF.
Heavy duty conveyors
Whether transporting raw coal or metals at a mine, or bulk materials and finished goods at a port, heavy (or bulk) conveyors often endure abrasive contaminants under dirty, wet conditions that challenge component reliability.
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The surging population, rapidly growing economies and burgeoning global development, particularly in areas such as the Asia-Pacific region, are the main drivers behind an ever increasing consumption of mineral commodities and ore bodies.
In order to meet the rampant demand, raw material suppliers the world over are now under heightened pressure to ensure that sufficient supply is in place to satisfy the need.
And there is further pressure in the form of tightening regulatory requirements and rising energy, raw material and waste disposal costs that only serve to compound the issue. Consequently, these challenges see many plants being forced to drive down energy consumption and emissions in order to remain environmentally responsible and commercially competitive.
Increasing productivity and reducing costs are the keys to success in surviving the sector and, as a result, many organisations are now increasingly looking to contain and reduce costs to sustain profitability, primarily through improvements in machine performance, reliability and efficiency.
In many cases, the key to achieving these goals lies not just in addressing the performance of larger systems, such as engines and gearboxes, but by taking a holistic view and evaluating the system as a whole. By focussing on the components of the conveyor, operators of mining plant and equipment can realise significant cuts in operating and maintenance costs, while maximising equipment performance and life in service.
A range of products and services are now available that optimise conveyor performance and efficiency, including lubrication, alignment and housing solutions.
For example, where a conveyor tracks substantially off course whilst feeding the belt through the idler system, poor tracking is often the result of poor pre-alignment of the pulleys and idlers. In such cases, geometric alignment of the entire conveyor assembly – including drive trains, pulleys and idlers – may be required.
Precision conveyor alignment can be achieved using a combination of techniques and several laser alignment tools ranging from advanced geometric alignment to basic belt alignment lasers.
As a result of the precision geometric alignment, conveyor belt commissioning times can be reduced considerably when compared to conventional methods of belt tracking where idlers have to be adjusted continuously in order to train the belt along its pathway.
The benefit to the customer after the alignment process is an extremely smooth start-up with only minor adjustments needed in order to be fully productive.
The precision alignment also results in a greatly reduced risk of belt damage during the commissioning and training period. Further expected benefits are longer operational life of the idlers and pulleys, as unnecessary stresses have been removed from these components prior to full production operation.
Components such as bearings are present in virtually every piece of industrial machinery, so when a breakthrough in bearing technology is made that offers notable energy savings, the benefits can be applied across industry.
Improvements made to just one piece of equipment, such as the ubiquitous conveyor, which often incorporates many hundreds of bearings for pulleys and idler rollers and in drive motors, can have a profound impact on energy consumption.
With this in mind, a range of highly efficient, low friction bearings that cut frictional torque has now been developed. The new bearings reduce friction, and thus energy consumption, by as much as 50%, depending on the application. Perhaps as importantly, bearing life can be increased to give a major reduction in total cost of ownership.
Similarly, the latest high performance seals are perhaps more effective than ever at providing protection against the intrinsically harsh operating environments of mining applications, preventing system contamination resulting from the ingress of particulate matter and moisture. Furthermore, a correctly specified seal provides low levels of friction, retains the lubricant and essentially extends bearing service life.
Conveyors in food and beverage
In proving ovens, high pressure wash-downs and humid operating conditions cause premature failure to conveyor chains and bearings, leading to an increased risk of product contamination and unnecessary maintenance and re-lubrication costs.
Under these conditions, moisture, water and cleaning fluid will creep into bearings, resulting in reduced lubrication. This is because the bearing grease will absorb the water and emulsify, changing the consistency of the grease and allowing it to wash out. Along with corrosion accelerated by the humid environment, this can cause the guide wheel bearings of proving oven conveyors to fail.
Prompted by customers that have experienced similar difficulties the designers and engineers of conveyor components have worked with OEMs to review the system and minimise such maintenance issues in the future. An efficient solution that has emerged from this collaboration is the use of air-assisted oil projection lubrication systems to address issues connected to manual chain lubrication.
An air-assisted oil projection lubrication system enables reliable and effective lubrication of the conveyor chain, eliminates related downtime and reduces maintenance costs. Through accurate oil projection, the system prevents lubricant waste and reduces environmental and operator safety issues created by excess oil.
Volumetric piston pumps precisely deliver a metered volume of lubricant to the points of friction while the chain is in operation, while a control unit can be preset to the preferred timing for lubricant application. Because the projection nozzles have no mechanical contact with the chains, dirt accumulation and applicator wear are prevented.
The chain does not need to be stopped for re-lubrication, so productivity is increased, while longer service life is achieved due to decreased chain wear and reduced friction lowers energy consumption.
In food and beverage applications such as this, an air-assisted oil projection lubrication system also helps support the HACCP process in producing safe food by preventing contamination from the lubricant.
