Carrying the bulk load -keeping up with conveyor belt technology

Improved maintenance reduces risk, raises profitability in conveyor operations

Few would argue with the assertion that a single serious conveyor accident can cost more money and anguish than virtually any safety programme. Most people would also agree that employees in conveyor-relayed industries deserve to have the safest workplace that is reasonably possible. Yet as downsizing trends advance and the economy continues to struggle, there is a temptation to postpone maintenance activities and safety upgrades in an effort to preserve profitability.

Unfortunately, there are a number of subtle expenses that typically result from this approach, ultimately costing far more than the savings from service and safety cutbacks. And many of the concerns are the same issues that conveyor operators first identified in the 1930s. The primary difference is that conveyors are larger, longer and faster in today’s operations, with greater power and risk potential. When coupled with increasing productivity demands, particularly on aging equipment, plant owners can put themselves and their earnings at unnecessary risk.

THE PATH TO INJURY

Conveyors apply large amounts of mechanical energy to what is essentially a giant elastic band, stretched tight and threaded through a maze of components. This stretched band is burdened with a heavy load of material and moved at high speed, sometimes with drive motors as large as 600HP (450kW).

Given the inertia and kinetic energy, enormous forces are involved. The human body, able to generate less than 1HP, is simply no match.

A report from the Mine Safety and Health Administration found that over a recent four-year period, more than 40% of injuries were caused while a worker was performing maintenance or checking a conveyor. Nearly as many more were hurt while the subject was cleaning or shoveling near a moving belt.

In another study of more than 200 fatal mining accidents, data compiled by MSHA and the U.S. Department of Labor observed that 48 of those involved conveyors. Activities most often leading to conveyor-related fatalities were maintenance (such as replacing idlers or clearing blockages) and cleanup (including shoveling or hosing). Together they accounted for more than 50% of the total.

In 2007, the National Safety Council in the United States estimated the average cost of a work-related death to be around $1.2 million, a figure that’s likely to be even higher now. The accounting included medical expenses, wage and productivity losses and administrative costs, but not property damage.

TRAINING

The single most critical element in conveyor safety and efficiency is training, beginning with management. While managers are often too busy to take a course on conveyor systems, they’ll frequently require attendance by an employee who has little or no influence in the decision-making processes that affect the safety and efficiency of the plant. The commitment to reduced risk must be initiated by managers and supervisors, if they expect the troops to buy in to the concept.

Many industries require specific amounts of training for new employees, and some demand continuing education, a good practice for reducing risk and maximizing productivity. These programmes typically provide an introduction to the work environment, and may also include topics such as hazard recognition, risk avoidance and health/safety. Unfortunately, there are few standards that focus on conveyor training, and in light of the number of conveyor- related accidents each year, it appears that existing programmes have not accomplished their mission.

As part of a good training programme, operators will learn the importance of observing the speed limit and capacity rating on any conveying system, ensuring that design specs are not exceeded. A safety ‘walk-around’ will become second nature any time inspection or repair is performed, so that all tools and work materials are removed before re-starting the conveyor. In a well- designed system, emergency shut-offs and controls will be located close to the belt, with ready access that is unobstructed by debris.

It’s important that only competent, well-trained personnel — equipped with the proper tools — perform conveyor service and maintenance. These individuals should be trusted veteran

employees empowered with the authority to shut down a conveyor for minor repair that is likely to prevent a major outage or equipment expense. One way to optimize maintenance is to document standard procedures for performing each task, ensuring that it’s completed in the safest and most efficient manner possible.

A computerized maintenance management system (CMMS) is an excellent tool for archiving these service procedures. The specialized software will administer work orders and manage information, so the maintenance staff can perform tasks according to priority. Most systems will also track expenditures, an essential element in justifying equipment upgrades or purchases.

BELT SELECTION

While it might sound basic, improper belt selection remains a common problem in conveyor systems, decreasing belt life and creating potential hazards. Belt conditions such as cupping and camber are often a result of improper specification, which leads to spillage, mis-tracking and improper loading. Belt selection must be based not only on the system length, width, material conveyed and angle of incline, but also on the parasitic drag of components such as idlers, bearings, belt cleaners and skirt board seals.

In specifying the correct belt, thicker is not always better. It should be selected to deliver the proper pounds per inch of width that it’s intended to carry, as well as the optimum trough angle, aspect ratio and cover material. While many suppliers are simply middle men who will sell whatever stock belt is best suited to the application, a better match will usually be obtained by using a quality software programme to design and select the belt according to specific criteria.

FUGITIVE MATERIAL

One of the primary approaches to reducing risk and improving profitability is to manage fugitive material. There are many ways that fugitive material from belt conveyors can create hazards, the most apparent being that it creates the need for personnel to perform maintenance around moving conveyors. Any time that employees are in close proximity to the moving belt, even minor or inadvertent contact can become a serious injury or fatality in just seconds.

By nature, spillage costs money. If people are cleaning up fugitive material, they’re wasting labour. If material is escaping, it’s wasting a valuable resource or product. While some operations can return the spilled material to the process, it often contains impurities that can raise product quality issues.

In other facilities, the material must be discarded or washed away, a particularly expensive approach if the conveyor’s contents have already undergone some amount of refining by the time they reach the spill point. In an example not uncommon in bulk materials handling, one facility conveying 800tph (tonnes per hour) was found to be literally washing an estimated $1.2 million worth of material down the drain every year. An effective system of fugitive material control that is properly installed can drastically reduce waste, often paying for itself in as little as 6–12 months.

Another problem caused by fugitive material is flow restrictions. Chute or bin blockages can bring even a large-scale process to a standstill, causing thousands of dollars in downtime, corrective measures and lost production. Blockages can also cause material boilover and sudden surges, as large amounts of material suddenly break free and drop through a receiving vessel and onto the belt. Both conditions are major contributors to spillage, which can also introduce belt tracking error that can damage equipment and increase the risk of injury. A well-designed conveyor system will often employ skirtboards for reducing spillage and dust, used to contain the load as material is placed on the belt and until it assumes a stable profile. Skirtboards at each transfer point must be engineered to match the characteristics of the material, the receiving conveyor, drop height and transfer point design.

Another form of fugitive material is dust, whether settled or airborne. In addition to the potential fall hazard, risk occurs primarily when fine, lightweight particles are sufficiently disturbed to launch them into the air, where their low mass causes them to hang suspended and travel in the wind.

Dust inhaled by workers or members of the surrounding community can irritate airways and exacerbate conditions such as asthma. From a purely financial perspective, when equipment air intake includes significant amounts of dust, it can lead to more frequent maintenance and greater engine wear, causing operating costs to rise. Conveyor dust can also generate complaints from local residents and businesses, affecting community relations, creating obstacles to future operating permits or leading to increased scrutiny.

As material escapes, it accumulates on idlers and other components, contributing to premature failure. Once a bearing seizes, the constant belt movement can wear through an idler shell with surprising speed, leaving a razor- sharp edge that poses a threat to workers and the belt itself.

Spillage can also contribute to the risk of fire by interfering with pulleys and idlers and by providing potential fuel. Most conveyor fires are ignited by friction-generated heat from a pulley turning against a stalled belt or a belt moving over a seized idler. A conveyor belt fire of any size is a serious issue, not only because the belt or its contents may burn, but also because the length and movement of the belt can spread a fire a great distance in a very short time. One overheated bearing and a small amount of powdered material can quickly turn into a large-scale event. Even worse, in confined spaces, airborne particles can create the right ingredients for an explosion.

An elastomer edge seal is often used to prevent the escape of fines, typically constructed from steel plate. In addition to managing the bulk material to control spillage, the skirtboard and sealing system form a settling zone that contributes to effective dust management. In this zone, the air current travelling with the material stream is slowed and controlled, allowing airborne particles to fall back into the bulk material.

When a conveyor has multiple loading points relatively close together, it may be advisable to install a continuous skirtboard between the loading zones. An experienced supplier of conveyor technology should be well-versed in the design options and able to provide sound advice on optimum features to suit an individual application.

The symptoms of carryback are most often seen as return roller buildup that causes belt tracking problems. Often, an employee will try to clean the return roll while the belt is running, a highly dangerous and potentially fatal decision.

Absent or inefficient belt cleaning is both a safety hazard (because an employee is typically required to somehow remove the carryback) and an efficiency drain (because this material isn’t getting delivered to the desired destination). While it may seem like a small amount of inevitable waste, in reality it’s a preventable loss. If it’s material that has already been processed in some way, then an even greater investment has been made without any return. Belt cleaning systems can drastically reduce the amount of carryback. Unfortunately, many bulk material handling systems exhibit symptoms of all forms of fugitive material: spillage, carryback and dust, complicating the effort to correctly identify the sources and apply effective remedies.

GUARDING

It’s essential that pinch points be equipped with well-designed guards to prevent accidental or unwise encroachment by employees. This includes rotating components like pulleys and idlers, as well as equipment that may create sudden movement, such as gravity take-ups. Many plants are beginning to totally enclose hazardous spaces as a way of protecting employees and visitors using walkways and inspection points, with heavy guards fabricated from metal mesh or screen that permits observation of moving parts without posing an opportunity for injury.

Safety guidelines for the US are published in ASME Standard B-2.1-2006: Safety Standard for Conveyors and Related Equipment and in B15.1: Safety Standard for Mechanical Power Transmission Apparatus. While almost every nation has individual requirements that apply to the placement of guards, local and general industry standards should also be consulted and implemented.

SCHEDULED INSPECTION & MAINTENANCE

It’s easy to focus on the fact that companies make money only when the conveying system is loaded and running, especially if employee compensation is tied to plant performance. As a result, there’s a reluctance to shut down a running line until there’s a compelling reason, which creates a ‘We’ll fix it when it breaks’ attitude.

What some managers fail to recognize is that this approach will change their conveyor service from scheduled maintenance to crisis management. Such short-term thinking is an almost certain path to component failure — probably catastrophic — which will ultimately cause more system downtime, higher repair costs and more labour investment than if a sensible plan had been created and followed from the outset.

It’s critical that the production schedule allows adequate system downtime to perform necessary inspections and maintenance. A formal inspection and service schedule must be developed for the material handling system and followed religiously. This programme should include review of emergency switches, lights, horns, wiring and warning labels, as well as the conveyor’s parts and accessories, such as chutes, cleaners and other components.

There are certain conveyor safety practices that should always be observed, regardless of the size, design or operating environment. Lockout/tagout/blockout/testout procedures must be established for all of the belt’s energy sources, as well as accessories and associated process equipment. Bulk material handling systems can still present a hazard from the energy that is stored in a stretched belt after its motion has stopped, which can cause the conveyor to move suddenly, even when the system is de-energized.

SAFETY BY DESIGN

The most efficient way to address conveyor safety and maintenance is by building the system from the outset with those features in mind. But even without that luxury, a thorough evaluation of the conveyor system will help identify potential problems and upgrades, whether performed by a qualified staff member or by an experienced independent supplier.

While any conveyor supplier can build a system to transfer material from one place to another, adding safety and fugitive material control as critical elements will complicate the equation for some manufacturers. For optimum safety and productivity, a conveyor system should be designed for easy installation, maintenance, repair and cleanup. Specifiers should look for standardized components that can be easily serviced; maintenance access points at strategic locations; comprehensive barrier guards at all pinch points; and upgradability options to meet future requirements.

The design should provide adequate walkways, platforms and utilities such as water, electricity and compressed air to facilitate maintenance and service. Modular components such as track- mounted pulleys can deliver slide-in/slide-out convenience. Even if a procedure is only required infrequently, the time and money savings can be significant.

Dust-resistant structures, engineered flow chutes and properly designed skirtboards all contribute to fugitive material control, helping to reduce maintenance and downtime. Common features such as wear liners, seals and belt cleaners help minimize waste and maintain consistent belt tracking, while customized designs may include specialized chutes and belt-washing systems. Modern 3-D drafting and fabrication techniques now allow conveyor suppliers to build and arrange components in non-traditional ways, without greatly increasing the costs.

CONTRACT SERVICES

When the economy lags, plants often reduce their head count. In an effort to concentrate the efforts of remaining staff on core activities and stabilize maintenance costs, many bulk materials handlers are entrusting their conveyor installation and service to outside contractors. Most will find the best success with specialty contractors whose sole focus is conveyor systems and bulk material flow. These specialists, employed by a proven manufacturer, trained and certified to specific standards, will have conveyor expertise which exceeds that of a general contractor.

Having an outside expert opinion often helps to identify problem areas that plant personnel may have come to view as normal. Some suppliers will offer to ‘walk the belt’ and provide a state-of-the-system report from observing it in operation. While no repairs should ever be attempted with the belt in motion, watching and listening to the system will help an experienced conveyor mechanic to identify components in need of attention, often before a catastrophic failure or safety incident occurs.

Trustworthy parts/service providers will provide upfront quotes on the equipment and labor they supply, as well as performance guarantees to ensure customer satisfaction. They should be skilled in conveyor science and safety, able to identify opportunities for system improvements and quantify the potential benefits. Some will also offer operator training programmes and continuing education, helping to facilitate a company-wide commitment to safety and preventive maintenance, while fostering a culture of continuously reducing risk and enhancing plant performance.

At the core of Rulmeca’s high- quality rollers, motorized pulleys and components for belt conveyors are three brands steeped in history, innovation, international development and research. Founded in 1962 by the entrepreneurial Antonio Ghisalberti and still guided by Emilio Moreschi (Group President), RULMECA S.p.A. has been able to harness and employ the experience and expertise acquired by worldwide expansion. Today the Rulmeca Group consists of more than 20 companies that provide manufacturing, sales and distribution capabilities to most of the major global markets and the Rulmeca, Melco and Precismeca brands are globally recognized for excellence.

Globalization has for many years been an integrated part of Rulmeca identity.

With the manufacturing strategically placed in Europe, Asia, Africa and the Americas, the Group of Rulmeca Companies offers competitive products that meet the highest international standards as close to the customers or project site as possible. Locally they have the necessary commercial, product and application knowledge required to provide a full consultancy service, ranging from planning of new projects to aftermarket and troubleshooting.

At Bauma 2013 Rulmeca will display the complete range of idlers/rollers and motorized pulleys: special focus will be given to the new belt tracking roller, to the anti runback roller and to the 1000HD motorized pulleys.

Widely used in the mining industry and other conveyor related industries, the Rulmeca belt tracking roller responds instantly to the misalignment of the belt and does so without special modifications to the structure. The Rulmeca belt tracking roller accommodates belts ranging from 450–2,300mm.

newly developed motorized pulley with an outstanding power range of 160–250kW, making it the largest and most powerful motorized pulley available from any supplier globally.

Dirty deeds in the conveyor belt industry?

Most of us have long been aware of the increasing trade in counterfeit goods. Such activities are usually associated with famous ‘designer’ brand names within the fashion industry and also illegal duplications within the world of music and film. Many consumer protection organizations are reporting a huge increase in complaints fuelled by the economic crisis with the food industry being particularly hard hit. But counterfeiting and ‘misrepresentation’ is even affecting the normally unglamorous and unexciting world of conveyor belt manufacturing. Because of the potentially serious consequences to many of our readers we decided to take a closer look by talking to senior managers at one of the most famous brand names of them all, Netherlands- based Dunlop Conveyor Belting.

“Conveyor belt manufacturing has always been a highly competitive industry and that can only be a good thing for the end-users,” explained general sales manager Les Williams. “But what isn’t a good thing for users of conveyor belts is that we are seeing a growing trend where lower quality belts, often of very dubious origin, are being bought by some unscrupulous traders and distributors and then sold on as being manufactured by one of the relatively small number of ‘big name’ brands. I can’t speak for others but we are certainly victims of this practice; and the problem is growing.”

WHAT IS HAPPENING?

So, what is actually happening? Well it appears that the major manufacturers are unwitting victims of these dirty deeds. No evidence has yet been found which points to a manufacturer falsely branding its products. In other words, there is no sign of actual counterfeiting. What does seem evident, however, is that large scale ‘dumping’ of belting, primarily from Asia is now taking place on an unprecedented scale. And with the trading and fitting of conveyor belts to end users worth many millions each year, it is hardly surprising to find some who are willing to deceive in

order to earn bigger profits. Rather than buy direct from the manufacturer, a large

proportion of belts are purchased by end-users from traders as well as from vulcanizing companies and distributors who supply and fit the belts. This is a long-standing practice and according to Dunlop, the majority of traders and distributors operate perfectly honestly. However, Dunlop maintains that it is finding more and more cases where its customers believe they have actually been supplied with genuine Dunlop belts but which in reality have actually been manufactured elsewhere and are invariably of inferior quality or below the required international standards.

End-users are increasingly insisting that their belts should be made in Europe rather than, say, in Asia. However, even this approach can be prone to malpractice with belts imported into Europe, housed in a warehouse and then re-shipped to customers using certificates that state the country of origin as being European.

IDENTITY THEFT

Dunlop recently discovered that it has become a victim of another illegal practice that virtually amounts to identity theft. An organization in India (as yet unidentified) has created a website using the Dunlop Conveyor Belting name and has even copied text extracts from Dunlop’s own website to create the illusion that it is Dunlop’s official Indian operation. This enables it to attract enquiries from would-be Dunlop customers who innocently believe that they are buying genuine Dunlop quality at lower prices.

SERIOUS CONSEQUENCES

Not only are such practices illegal, they also have very serious consequences not just for the big name manufacturers but also for their customers and authorized distributors. Sales and marketing director Andries Smilda has worked in the industry for more than 20 years and he believes that the problem has a very widespread impact. “Dunlop has established a worldwide reputation over many generations for producing conveyor belts of the highest quality and naturally that is of enormous importance to us,” said Smilda. “If our customers buy belts of inferior quality in the mistaken belief that they are using Dunlop then that will not only result in lost sales but also damage our good name and the good name of our authorized distributors, agents and service partners. Using inferior quality belts also puts our customer’s operational efficiency at risk.”

It has long been standard practice for Dunlop to carry out exhaustive laboratory tests to measure performance qualities and conformity to recognized international industry standards. These tests are not only performed on the company’s own belts but also those of its competitors. “We have to know precisely what we are competing against so that we can maintain quality and continue to develop even better products. We must also enable our salespeople and distributors to prove the superiority of our products,” explained Smilda. “You would be amazed at the differences between our belts and those of other manufacturers. The difference in vital qualities such as resistance to abrasion or heat can easily be up to 50% or more. Conveyors can carry tonnes of material at quite fast speeds. If these belts fail or if they are not sufficiently resistance to fire for example then the results can potentially be very dangerous.”

Several examples were pointed out by the Dunlop technicians including one where a unique specification of Dunlop belt (UsFlex) had more than three times greater rip and tear resistance compared to what they referred to as ‘cheap imitations’. One of the problems seems to lie with the fact that, at first glance, industrial conveyor belts all look very similar — big long lengths of thick black rubber! According to Smilda, to the untrained eye it is almost impossible to tell just by looking at the belt. “The end user who thinks he has bought a quality belt at a cheap price can often face paying a heavy cost in the longer term because the belts do not last so long and/or they incur lost production and higher maintenance costs.”

MORE LEGISLATION?

Does the answer lie with extra legislation of some kind? The Dunlop management certainly do not think so. They argue that the law in most countries, especially within Europe, provides sufficient recourse if malpractice can be proved. Somewhat surprisingly, they lay much of the responsibility on the doorstep of manufacturers including themselves. Research and development director Dr Michiel Eijpe says that permanent branding during the production process has not always been consistent. “I think that perhaps we [Dunlop] have been a little complacent in the past but times have obviously changed. During the past few months we have introduced new branding methods using coloured rubber compound vulcanized into the belt that describes the belt type and also includes the wording “Made in Holland”. We also place much more emphasis on the use of branded packaging, again making the fact that the belts have been made in Holland very visible”.

BUYER BEWARE!

Dunlop’s advice to all who buy conveyor belts, regardless of supplier, is never assume that the belt being delivered is precisely what was ordered. It urges caution and recommends that unless the belt has been delivered directly from the manufacturer then a few basic checks should be carried out before fitting. “If the original manufacturer’s packaging has been used then that is a good sign but unless it is a full sized roll then there may not be any packaging,” explained Les Williams. “The most important check is to inspect the top and bottom surfaces of the belt to see if the manufacturer’s branding can be seen.”

Schenck Process systems ideal for handling bulk commodities

Schenck Process belt conveyors can be used for the handling of dry bulk products. Some of the company’s systems are detailed below.

MULTIDOS® WEIGHFEEDER

The MULTIDOS® weighfeeder (see pictures) can be used in an extremely wide variety of ways for continuous gravimetric feeding, and it excels due to its high level of accuracy of ±0.5%. It is integrated into the MULTIDOS® product family, with application-specific series to fit every need. The MULTIDOS® E series weighfeeders are specialized for many applications and

Solutions package

A flatbelt conveyor optimized for precise weighing, a three-phase AC drive system with speed sensor, and integrated weighing sensors.

Quality features and design consistency

Reliability, accuracy and a consistent ‘less is more’ design pay off time and time again: the measuring roller that is placed directly on two load cells and the mechatronics concept ensure stable, long-term feeding results. Lifetime lubrication of the bearings and a weighted belt tensioning system make the system remarkably low maintenance.

MULTIDOS® VDP

This is an apron weighfeeder for poorly flowing and ‘sticky’ materials. In the past, transporting ‘sticky’ bulk materials presented an almost insoluble challenge. However, achieving the impossible has never been an obstacle to Schenck Process’s development specialists. With the MULTIDOS® VDP, it has developed an ideal economic solution.

There’s no such word as “impossible”! MULTIDOS® VDP reliably feeds even sticky materials such as clay, marl, trass or  sludge with the high degree of accuracy that a weighfeeder can provide.

More precise feeding is possible, with stable, reproducible quality improvement.

The weighing technology has been integrated into the track of the VDP apron weighfeeders. Silo discharge and gravimetric feeding functions are now united in a single unit. This results in significantly better feeding accuracy compared with volumetric extraction apron feeders in the past.

The result: stable, repeatable quality improvement in the mixing plants. This represents quality which is well worth it, thanks to its low investment costs and high feeding accuracy of +/- 1%, compared with the actual feed rate.

MULTIBELT^®

Maintenance-free, flexible and precise weighing on a moving conveyor belt. Flexibility is required to measure continuous, different material streams. This is a requirement which Schenck Process conveyor belt scales meets extremely well. They can be used virtually anywhere: in the pit and quarry industry, in heavy industry, or in the foodstuffs and chemical industries.

The right solution for every application

The applications include production and logistics, throughput and consumption rate measurement for production systems, internal balancing of supply and withdrawal, load limit signalling, batching at loading stations or pre-feeder control and legal-for-trade weighing. Schenck Process belt scales are as precise as required — with an accuracy of +/- 0.25%.

Multi-idler belt scales

MULTIBELT^® BMP is an dual-idler belt scale for feed rates up to approximately 15,000tph (tonnes per hour), whereas MULTIBELT^® BMC is a multi-idler belt scale for feed rates up to around 20,000tph.

Single-idler belt scales

MULTIBELT^® BEM is a single-idler belt scale for feed rates up to approximately 4,000tph, whereas MULTIBELT^® BEP is a single- idler belt scale for feed rates up to around 6,000tph. Finally, MULTIBELT^® BED is a single-idler belt scale for feed rates up to approximately 15,000tph.

MOVEMASTER^® EN-MASSE CONVEYING AND ELEVATING GENTLE HANDLING OF BULK MATERIALS

Movement of the chain when buried in the material will induce the whole mass to move forward gently in a solid, placid column ‘en-masse’. Material dragging, particle tumbling or rolling does not occur. MoveMaster® Conveyors are manufactured in a standard range of sizes from 200mm wide upwards, enabling them to meet every requirement. Multiple inlets and/or outlets for conveyor intake or discharge. ‘Two-way’ conveyors will convey in both directions.

Movement of the chain when buried in the material will induce the whole mass to move forward gently in a solid column. The eleveyor design permits the column of material to be moved vertically or on an inclined plane. Eleveyors are manufactured in a standard range of sizes from 200mm wide upwards, which enables them to meet every requirement.

Cost effective

Capital costs prove very competitive with other forms of handling equipment, thus giving quicker ‘payback period’. Power running costs are significantly lower than most other forms of equipment, i.e they can be as low a 1/10 of dense phase conveying. Maintenance costs are also low. Heavy duty rigid construction in simple modules, high strength chain, choke detectors, overload and underspeed switches all ensure easy maintenance at infrequent intervals.

Labour saving

Manual to fully automatic control of single or multiple machine systems provided by proven BASIC control systems. No specialized maintenance staff required.

Environmentally acceptable

Totally enclosed machines and transfer points of dust-tight and weatherproof construction. Safe as all moving parts are totally enclosed.

Versatile

Specialized features of ‘en-masse’ equipment offer versatility to plant layout. Handles virtually all types of dry bulk products.

Size

Size and duty comparison with alternative forms of handling equipment.

Gentle handling

Materials moves ‘en-masse’ slowly in a solid placid column with the conveying elements; thus degradation is virtually eliminated. Chain design permits material column to change direction through bends, without degradation.

Conti^®Protect Belt Rip Detection detects longitudinal slitting early on and prevents extensive damage, reducing repair costs and accident risks.

Longitudinal slitting in conveyor belts can be costly. Sharp objects always end up on the conveyor belt together with the materials conveyed, especially in the mining industry, in wood processing, or in recycling plants. “If they fall in an unfortunate position during belt loading, they may get caught up and split the moving conveyor belt longitudinally. In the worst-case scenario, the belt can be written off completely,” asserts Dr.Andreas Jungk, application engineer at ContiTech Conveyor Belt Group. More protection against failures and expensive repairs is provided by the new electronic monitoring system Conti^®Protect Belt Rip Detection, which has only been on the market for a short time. It detects longitudinal slitting early on, minimizes damage, and thus cuts cost and reduces the accident risk. This makes it possible for the conveyor belts to be used for even longer. Conti^®Protect Belt Rip Detection can therefore contribute to reducing operating costs and protecting the environment.

AUTOMATIC STOP PROTECTS CONVEYOR BELT

Monitoring takes place via conductor loops, which are vulcanized into the conveyor belt. These loops transmit a high-frequency signal between a transmitter and receiver. If a loop is damaged, the signal will break down on the receiver end. The system control then stops the conveyor belt automatically. How long the system needs to come to an emergency stop is determined by the distance between the conductor loops, which can vary between 20 and 50 metres. During an initial learning cycle, these distances are recognized and saved by the system.

The new monitoring system is also extremely easy to use. “All the signal sequences can be called up electronically so that, if necessary, one can conclude from them about the quality of the loops. An Ethernet connection means that the system can be controlled via a PC and also via the Internet,” explains Jungk. Many of the systems allow ContiTech specialists to connect to the system on request to carry out remote maintenance. All of the components used in the Conti^®Protect Belt Rip Detection system are extremely robust, which enables them to meet the high demands of the mining and bulk material industries.

Conveyor belts can do more than just transport unit loads or bulk cargo from A to B, writes Michael Labbé of REMA TIP TOP Latin America Spa. They form the backbone of efficient production processes, particularly when faced with current economic challenges such as raw material shortages and exactly synchronized global value-add chains. Conveyor belts and conveying equipment are thus a central influencing factor for companies’ competitiveness. To maintain their peak performance over the long term, regular maintenance is a must. The timely exchange of worn components can effectively prevent a sudden failure of the conveyor belt. A project in the Chilean Los Pelambres copper ore mine, however, demonstrates how such economic loss can be avoided. Here, while still in operation, two of the heaviest-duty conveyor belts in the world — with a total length of 23km — were completely replaced.

Whether in mining or general industry, conveyor belt systems nowadays form an integral part of both the raw material extraction and modern production. They optimize transport routes, make complex logistics processes more efficient and bridge short or medium distances for the transportation of goods. The demands on the conveyor belts concerned are many and high. As well as high levels of conveying performance and load-carrying capacity, factors such as low wear and maintenance costs and a high degree of production safety play an important role. Another main goal of the operators of conveyor systems is to have the conveyor belts run as efficiently as possible over a long service life and avoid downtimes to the greatest possible extent.

FLEXIBLE SYSTEM SOLUTIONS FOR COMPANIES

In addition, every industrial sector assesses the characteristics of the system differently. Conveyor belts in the raw materials industry, for example, need extremely high levels of tensile strength and operational safety as well as extreme resistance to wear to be able to cope with the load caused by the transported materials over long distances. To meet these differing operator requirements, custom-made and flexible system solutions are required that are matched to that particular location of the conveyor system, its type of use and the range of tasks involved. Flexible solutions for the construction of plant equipment therefore also require a flexible approach to the repair or maintenance of these systems.

For conveyor systems used for raw material extraction, the belt and other components must be changed after a certain operating time. Conveyor systems used in opencast mining are exposed to particularly difficult conditions that affect the structure of the belt and thus limit its life expectancy. On the other hand, the extraction of natural resources, particularly in regions that are geographically exposed, has again become very lucrative. High demand from the industries of economically emerging nations, the resulting scarcity of certain resources and their increase in price are making conveying projects that were only a few years ago classed as unprofitable again attractive. In this case, the materials and equipment used are often exposed to extreme temperatures, higher levels of insolation or high humidity levels.

REPLACING THE HEAVIEST-DUTY CONVEYOR BELT IN THE WORLD

An example of this is the replacement of two conveyor belts in the Chilean Los Pelambres copper ore mine, one of the most profitable copper mines in the world. This opencast mine lies in the Andes at a height of 3,300m. More than 8,000 tonnes per hour of copper ore are transported for further processing at a height of 1,600m by means of steelcord conveyor belts. At times this means downhill transport gradients of up to 10% for the conveyor belts. Together with the mine operator, REMA TIP TOP developed an approach which would allow the replacement of both conveyor belts without long plant downtimes, the goal being to keep production losses to a minimum during the maintenance work. “The normal method of changing a belt, making a splice and pulling it in roll by roll would have meant a downtime of over nine weeks” explains Jan Severing, Reliability Engineer at REMA TIP TOP. “Taking into account the then copper price of at least US$6,000 per tonne, an immense production loss of around US$250,000 an hour threatened.”

To keep the production loss as low as possible, a REMA TIP TOP team of experts created a sophisticated technical solution that permitted both belts to be simultaneously exchanged in parallel with the running operation. Both old belts were replaced by the new ones directly on site. In the first phase, half of the belt length was vulcanized together for each belt. The kilometre-long belt loops made in this way were positioned in pits made for this purpose and later attached to the existing belt. This process was then repeated for each second belt half.

A smooth sequence of events is decisive, particularly in critical phases such as this that directly affect the production operation. To ensure this, and taking into account the high weight of around 44 tonnes per belt length and the length of the splice, 13 people were permanently assigned to each belt. By having the trained personnel operate in two shifts, and through the high degree of work efficiency and the use of state-of-the-art materials and tools, both conveyor belts — a total length of 23km — could be simultaneously and successfully exchanged. The specialist team worked in the copper mine from October 2010 to March 2011.

“In addition to the high requirements regarding quality and work protection, the efficiency of the work processes was also right at the top of the priority lists for this project,” notes Michael Labbé, REMA TIP TOP Latin America Spa. “This meant that we had to use find and use tools and machines that were state-of-the-art, above all for time-consuming work such as the rubbing down of cover plates, the stripping and brushing off the steelcord or the filling of steelcord interstices. Only the assembly of the vulcanization process — with 10 heating plates and 48 beams — could not be accelerated through the use of machines. “Here the fitters were actually even faster than using a crane,” continues Labbé.

TAIM WESER reports on recent belt conveyor contracts

TAIM WESER has been supplying bulk handling solutions for over 100 years. Today, the company is able to provide optimum solutions for its clients within all industries including power sector, ports, iron and steel, fertilizers, mining and cement industries. Its solutions can be used to handle a wide range of materials including, grain, fertilizers as well as coal and minerals.

With an emphasis on innovation and technology,TAIM WESER has its own in-house R&D and design teams that create new products and develop projects using proprietary patterns and state of the art technology. TAIM WESER supplies its products on a turnkey basis and has specialized workshops equipped with state-of-the-art machinery that manufacture key components to the most demanding quality standards.

TAIM WESER provides either individual specialized equipment or turnkey installations, integrating all key elements and auxiliary equipment giving its clients tailor-made solutions. The company works with the latest technology and its product range covers all the necessary equipment for unloading, conveying, storing, reclaiming and loading of bulk materials.

TAIM WESER has consolidated its international position within the bulk handling market with various projects undertaken all over the world and in the last few years in Europe, South America, the Middle East and North Africa. Its bulk material conveying systems can be found in main industrial sectors, with lengths up to tens of kilometers and capacities of up to tens of thousands of tonnes per hour.

In this field,TAIM WESER has recently supplied and received order for various conveying system projects, such as two complete storage plants — one for petroleum coke and the other for sulphur — at a Spanish refinery. The scope of supply consists of two complete storage facilities, and includes the stockyard machinery. The petcoke storage facility is intended to transport the raw material produced in the drums and temporarily store in piles, to be taken later to the port facilities. In this case,TAIM WESER’s supply will include the petcoke crushing, transport, stockpiling, reclaiming, storage and truck loading operations. The longitudinal stockyard has a capacity of 75,000 tonnes and stockpiling and reclaiming capacities are 500tph (tonnes per hour) and 600tph, respectively.

The sulphur storage facility transports the solid particles generated during the solidification process at the plant and temporarily stores them in storage piles to be taken later to the port facilities. This operation also includes crushing, transport, stockpiling, reclaiming, storage and truck loading. In this case the longitudinal stockyard has a capacity of 30,000 tonnes and stacking and reclaiming capacities are 400tph and 500tph respectively.

CURRENT BELT CONVEYING PROJECTS

At the moment, the bulk material handling business unit of TAIM WESER is working on several recently awarded contracts related to conveying equipment. It will supply the iron ore conveying systems and stockyard machinery for the Super Porto Sudeste, the new port terminal which is being constructed in the Sepetiba Bay, Itaguaí, Brazil. Here,TAIM WESER will supply all the equipment needed for conveying operations, storage and loading of iron ore at the port stockyard. The equipment consists on the one hand of a complete conveyor belt system — from reception area to its loading onto ships, with a capacity of 12,000tph and a total length of 13,000m. On the other hand, the contract

includes four combined stacker/reclaimer machines with a stacking capacity of 10,000tph and a reclaiming capacity of 12,000tph to be installed in the two new iron ore storage yards.

In addition and also in South America, TAIM WESER is developing two new linked projects for the new loading and exportation port terminal for concentrated minerals (copper, zinc and lead) located in Puerto del Callao, Peru.

The first project comprises the concentrated minerals reception, storage and warehouse filling systems as well as the conveying systems for minerals sending to the open access point of the port terminal, for its onward transportation to the export area. The supply includes belt conveyors, trippers and feeders with capacities from 600tph to 2,400tph, and the project has been designed to provide a safety service both in the respect of the environment as well as the belt conveying.

The second project comprises the complete concentrated minerals loading and export systems. The scope of supply includes the belt conveyor system, capacity 2,500tph, to the wharf where the loading terminal and a rail-mounted shiploader (capacity 2,500tph, for vessels up to 60,000dwt) can be found.