WEBA CHUTE SYSTEMS ELIMINATE MATERIAL DEGRADATION

Uncontrolled discharge of bulk materials is undeniably linked to increased material degradation. And material degradation, in turn, affects final product quality and the bottom line. Weba Chute Systems has proved that correct design of transfer points will greatly reduce product degradation and in some cases, even eliminate it.

Custom engineered for individual application requirements, Weba Chute Systems are successfully moving materials in all commodity sectors worldwide. Managing director, Mark Baller explains that the company has always has a systems approach to bulk solids handling design and this is the foundation of the company’s successes.

In-depth understanding of material transfer as well as an insight into the differing operational characteristics of individual plants allows this transfer system OEM to configure solutions to suit particular application requirements.

“Our system uses a ‘supertube’, with a cascade scenario, where 95% of the material runs on material at the same time in a tumbling motion creating a boundary layer, rather than sliding down the chute,” Baller says. “Sliding particles cause extensive wear, while the tumbling or rolling motion created in Weba Chutes causes far less wear.”

The company has taken this a step further by designing the internal angle of its transfer chutes to match the product with the belt speed. Baller explains that by doing this, the product degradation can be significantly reduced or completely eliminated.

The Weba Chute System uses a streamlined scientific approach to the dynamics of bulk materials handling taking all aspects such as belt speed, belt width, material size, shape and throughput into account. The custom design allows control of the direction, flow and velocity of a calculated volume and type of material in each individual application and at the same time drastically reduces dust.

“It is this absolute control of material while being transferred that eliminates degradation but designing transfer points to achieve this requires an in-depth understanding of how material needs to be transferred taking factors such as changes of direction and the impact during these changes into account,” says Baller.

“The geometry of the system should be such that material is moved through the chute system with gradual directional changes and controlled velocity. This minimises impacts that lead to material degradation and dust generation,” he says.

In addition, discharge onto the conveyor system must be correctly controlled and be as close to the belt speed as possible. Controlling the transfer of material onto the conveyor belt guarantees increased cost savings as well as improved health and safety performance.

“Global best practice in Weba Chute Systems emphasises the incorporation of transfer chutes that have been designed and engineered to suit the specific application, with optimised plant design considering each element within the process flow,” Baller concludes.

TRAFO SUPPLIES TRANSFORMERS FOR DATA CENTRE APPLICATION

Data centres are energy hungry beasts that operate with a high power demand, and it is important that the most appropriate transformers with the requisite protection devices are specified for this robust application.

David Claassen, managing director of Trafo Power Solutions, explains that it is important to understand data centre applications and especially the load which the transformer will be supplying as well as the type of switchgear that will be feeding it. “This,” he says, “is important from a voltage transient perspective.”

Trafo Power Solutions recently supplied two 2000 kVA 11,6kV/415V dry-type transformers to a large data centre in the Cape Town. Manufactured under stringent quality control conditions at Italian transformer OEM TMC, these specialised units are low loss transformers which conform to the European Directive EU 548-2014 and will provide greater energy savings in this application.

“Dry-type transformers are ideal for data centre applications, and correct upfront design played a role in ensuring that these transformers will meet the application requirements,” Claassen says.

The design was important in terms of the transformers windings as well as the core changes in this type of application where there is a high percentage of non-linear or harmonic load. He says that in this case the design K-factor for these transformers is 13.

These transformers were designed differently to a standard distribution load transformer and have an electrostatic shield which diverts noise to ground as well.

Trafo Power Solutions was able to assess the application requirement and provide a solution that could be delivered within a tight delivery time frame, which was an added advantage to the end-user.

QUALITY IMPERATIVE IN ENGINEERED WALKWAY PRODUCTS

In any working environment where the safety of people depends upon the quality of the products used for walkways, cutting corners could be a recipe for disaster.

As a leading local manufacturer, Andrew Mentis has over 65 years’ experience in the manufacture of walkway products and the company is probably best qualified to comment on this. This is according to Lance Quinlan, national technical sales consultant at Andrew Mentis, who stresses that the use of a quality manufactured product is imperative.

“We have a solid track record of quality manufacture when it comes to engineered walkway materials including RS40 grating, expanded metal and Die Line. We simply do not compromise when it comes to quality,” he says.

Quinlan explains that when it comes to walkway products, it is a case of horses for courses. Probably the most commonly-known of all walkway products in industry is the Mentis RS40 40/40 floor grating.

“This is our number one premium brand, and is often considered the floor grating to have,” he says. He notes that the product has the kind of top-of-mind awareness in its market similar to which Hoover has enjoyed in the vacuum cleaner market.

The most important factor in flooring is the load-bearing capacity of the product. The design, engineering and manufacture of steel floor grating products have particular relevance to their structural integrity, and floor grating should always be viewed as an engineered product. It is formed through a process of compressive locking of the load bearing flat bars (bearer bars) and the round bar transversals to form an exact 40 mm2 pitch with openings of 35,5 mm x 32,4 mm and is designed with specific load-bearing characteristics.

Quinlan notes that expanded metal also has a wide range of flooring applications, and is ideal for catwalks, conveyor and access walkways and platforms. Good examples are walkways on large billboards, which need to ensure safe access to the billboard, as well as maintenance walkways on process plants.

Expanded metal walkways are lightweight and self-cleaning, have non-slip surfaces, interlocks at the joints, and hence no butt welds, as well as allowing the passage of air and light. Durable industrial flooring with excellent underfoot conditions is possible with expanded metal walkways and flooring from Andrew Mentis.

As a complete industrial flooring supplier, the company can help customers identify the most appropriate flooring solution for their application requirements.

Another of its products, which is ideal for incline conveyor walkways in particular, is Die-Line. This lightweight and economical walkway system offers flexibility in walkway design, is easy to erect and has excellent non-slip characteristics.

This range of positive grip-pressed section walkways is designed as complete walkway sections with integral kick-plates formed as a single unit. The elimination of heavy stringers or separate kick plates makes Die-Line quick, easy and safe to erect. The sections are designed for longitudinal spans and have a high strength-to-mass ratio.

“Emerging contractors are also increasingly using the company’s products as they become more aware of the safety concerns when it comes to walkway products,” he concludes.

ON SAFE PATHS WITH LEUZE

When using the principle of triangulation for navigating automated guided vehicles (AGVs), vehicles are often equipped with two different scanners – one for safety and one for navigation. Now there is a more cost effective alternative – the new Leuze RSL 400 safety laser scanner.

This innovative safety laser scanner not only ensures that AGVs are operated safely by means of protective and warning fields, but also simultaneously captures the measurement values for the navigation software. This means that only one scanner is needed for both safety and navigation.

Available from leading sensor specialist, Countapulse Controls, the Leuze RSL 400 safety laser scanner makes use of the latest technology resulting in measurement values with an extremely high angular resolution and accuracy.

The measurement value output of the device is optimised for navigation software which functions in according with SLAM (Simultaneous Localisation and Mapping). These characteristics allow the Leuze RSL 400 to precisely determine the position of the AGV.

The navigation software contains an image of the operating area including all fixed boundaries. The current position of the AGV is calculated by comparing the measurement values to this map. This concept is referred to as natural navigation.

With each revolution of its deflection unit, lasting 40 milliseconds, the safety laser scanner emits 2700 light pulses. These are scattered in all directions, and parts of the scattered light are transmitted back to the scanner. These are used to calculate the distance to an obstacle.

The more detailed and exact the measurement values of the scanner, the more precisely the AGV can navigate. With an angular resolution of 0.1, the Leuze RSL 400 can capture the environment in detail over the entire measurement range up to 50 metres.

This is achieved through a particularly narrow laser spot that maintains its perpendicular shape over the entire scanning angle. It also reduces incorrect measurements, the likes of which can occur on edges.
In addition to the angular resolution, distance values are also important. The Leuze RSL 400 offers an error accuracy of less than 30 mm resulting in high precision. Use of technology in the device has ensured that the values are not affected by the reflectance of the object, whether it is a reflector or a black wall.

The additional output of the received signal strength value for each beam allows autonomous detection of reflectors by the navigation software. When beams strike a reflector, the values differ greatly from any other environment. This makes simple and reliable detection possible.

Safety is also optimised with the Leuze RSL 400 scanner. The device offers up to 100 switchable protective and warning field pairs. The protective fields can be adapted to the respective movement and load conditions of the AGVs.

For example, in 4-field mode with 50 switchable field sets, the Leuze RSL 400 device can monitor up to four protective fields simultaneously. This enables safe and reliable reduction of the speed of the AGV. With its scanning angle of 270°, the device can also cover the front and side areas of AGV at the same time, i.e. it can see around the corner.

With these features and a maximum operating range of 8.25 metres, even large AGVs can be fully safeguarded used only two Leuze RSL 400 scanners.

Available various models with nine functional variants, three of which have data output for AGV navigation, the Leuze RSL 400 safety laser scanner offers four operating ranges – 3.0, 4.5, 6.25 and 8.25 metres. Models available with PROFIsafe/ PROFINET interfaces make it much easier to integrate the devices, particularly when many different protective field configurations are used.

OMV RAISES OUTPUT AND QUALITY AT GYPSUM PLANT

After significant upgrades and expansions to its manufacturing facility at Potchefstroom, leading gypsum supplier OMV has boosted its supply capacity while improving its gypsum quality.

OMV produces synthetic gypsum from the phosphate waste-product of the fertilizer industry, supplying the cement, agricultural and industrial sectors. According to OMV mechanical engineer Marinus van den Berg, the company has upgraded and automated its washing plant, while also adding a kiln drier and a calcining plant.

“The redesign of the washing plant included changing to a continuous lime batching system,” van den Berg says. “This improves the controllability of the process and the product quality. Standard deviations of the pH levels – a primary control parameter – are now down to 0,2 pH points.”

The washing plant upgrade meant full automation and higher availability. It also included a completely new laboratory, now staffed with a chemical engineer and chemical technician to focus on quality control. He emphasises the peace of mind that comes with a product of consistent quality. For industrial customers in particular, a dependable standard means less need to adjust their process in response to variabilities in the gypsum feed.

A key enhancement of the gypsum facility has been the addition of a rotary drying kiln. This allows reliable supply to customers even during the rainy months.

“The kiln reduces the moisture content in our gypsum by an extra 10%,” he says. “This has made our year-round supply more reliable, while the drier material also saves on road transport costs.”

An important part of the technology employed in the kiln is optimised fuel economy for lower carbon emissions. Along with the kiln installation has come the construction of an undercover gypsum warehouse with 30,000 tonne capacity. Dedicated stockpiles within the warehouse further enhance the customer experience.

“All these facilities operate within our total quality management system,” he says. “We continually optimise processes so we can pass the cost savings on to customers.”

Most recently completed is the calcining plant, which adds value to the gypsum product by producing a high quality Plaster of Paris. After extensive research into available technologies, OMV was able to construct and commission the plant in less than a year. It has also enhanced certain automation elements in the calciner.

“Once again, our focus has been on low process variability,” says van den Berg. “Through strict controllability, we have achieved high-quality and consistent output to open new markets.”

NOT JUST ANY PUMP WILL DO FOR A FILTER PRESS

As a mission-critical system in the mineral concentration process, the filter press demands a carefully selected pump to ensure optimal performance and uptime.

According to Marnus Koorts, product manager for slurry pumps at Weir Minerals Africa, the role of a filter press in recovering valuable saleable product is an important consideration for a mine operator. The high pressures associated with operating a filter press, however, often lead the pump to underperform.

“The operation of a filter press involves a wide spectrum of pressure and flow conditions within each cycle,” Koorts says. “This ranges from high-flow, low-pressure conditions when slurry is initially being pumped into the press, to low-flow and high-pressure when full.”

He emphasises that it is not enough to simply specify a pump for the average of this range of conditions. Rather, it is vital to establish the minimum and maximum values on the spectrum, and to specify accordingly.

“Filter presses in the market can demand pressures of up to 45 bar,” he says. “In many cases, therefore, the application requires high-pressure pumps such as the Warman AHPP high pressure range. Where lower pressure requirements are present, the newer technology of the Warman WBH could be used as it is generally a more efficient pump with longer wear life of spare parts.”

Failure of the pump to deliver enough pressure to the filter results in the solid-liquid separation process being inefficient. The selection of the right size of pump is therefore an important starting point in ensuring optimal operation.

With decades of experience in this field, Weir Minerals Africa has developed the expertise to advise on the best selection. It also offers a wide range of pumps suitable for application with filter presses.

The next key aspect of the customer’s selection, Koorts says, is the choice of sealing arrangement. This aspect of the pump can often lead to issues in the plant, when valuable product is lost through leakage.

“An expeller seal is not usually recommended, as the pressure it generates to seal the pump is generally not sufficient in a filter press application,” he says.

The stuffing box option can be used under certain conditions. However, the pressure of the surface water needs to be higher than the pressure inside the pump. This means that it would usually be suitable on a low-pressure pump for a low-pressure filter press.

“When the filter press requires a higher pressure, then the plant will have to provide a water line with a higher pressure to feed the gland, or it will not seal properly,” he says.

The preferred sealing option is a mechanical seal. While more costly, the mechanical seal can offer the customer substantial savings by preventing product being lost and downtime being incurred.

“While the benefits of a mechanical seal far outweigh its cost, it must be properly installed by a specialist,” he warns. “It is a unique piece of equipment and we see plenty that fail due to incorrect installation.”

A further consideration is the level of corrosive aspects of trace elements in the slurry. This can lead to rapid corrosion of mild steel pumps, and many applications require stainless steel options.

Comprehensive technical backup needs to underpin each step in this process, emphasises Koorts. For Weir Minerals Africa, this begins with its high quality local manufacturing process. This integrated process includes foundries for casting components, through to local componentry manufacture and assembly capability.

“This quality control and capacity feeds into our spares availability and service exchanges for refurbished pumps,” he says. “The result is quick supply through our strategically located branch network with 12 offices in South Africa and eight through the rest of Africa.”

NEW AGENT IN TURKEY TO BOOST MULTOTEC PRESENCE

Mineral processing specialist Multotec has appointed Istanbul-based Turbo Ltd as its new agent in Turkey, according to Bart Malan, Multotec’s international business development manager for Eurasia.

Malan says that while Multotec is not a newcomer to Turkey, having supplied a range of equipment over the past 19 year, there is a renewed focus on this region with the intention to expand its product footprint significantly.

“Over the years, Multotec equipment has been installed in the chrome, gold and coal sectors, and through the appointment of Turbo Ltd we will be able to extend our reach and include a larger range of proven Multotec solutions to the mining and minerals processing industry in Turkey.”

He says Turbo Ltd, an established company of 30 years’ standing, has a strong technical foundation underpinned by the requisite facilities to support its wide customer base. “Having skilled and qualified engineers as well as a strong support team and well-resourced technical capability was a critical consideration when appointing an agent in this important region as this we believe this is what is required to provide the level of support to Multotec customers,” he says.

“We also plan to collaborate with Turbo Ltd in setting up a fully operational laboratory in Turkey,” he continues. “This will give us the advantage of offering mineral test work and sampling for customers.”

Malan highlights that this facility will assist Turbo Ltd in their plant flow designs, supporting customers in maximising the efficiency of their mineral processing operations. While Multotec has historically marketed mainly cyclones and spiral concentrators in Turkey, the future will see a growing range of equipment include samplers, screening systems, flotation components, pumps and magnetic separators.

Turbo Ltd is active in the mining, metallurgy, construction, petroleum and natural gas sectors. With its head office in Istanbul and a branch office in Ankara, it also has a subsidiary in the UK and a logistic supply bureau in the US. The company has a strong focus on high quality aftersales service, and its Istanbul workshop is certified by the Turkish Standards Institute.

“We believe the Turkish market holds considerable potential for Multotec and we will work closely with our new agent to grow our market share,” Malan concludes.

LOCAL TECHNOLOGY AT THE CUTTING EDGE OF PROXIMITY DETECTION

With mine safety legislation getting progressively tighter, Booyco Electronics continues to ensure compliance with its proudly South African proximity detection system (PDS).

According to Pieter Janse van Rensburg, Booyco Electronics area manager for Mpumalanga, legislation coming into force in 2020 will mean the extended application of Level 9 safety standards. This level requires ‘full intervention’ from a PDS on trackless mining machines (TMMs) to avoid man and machine related incidents.

Booyco Electronics’ PDS can facilitate such collision avoidance, with automatic slow-down and even safe-stop of mining machines.

The system uses VLF antennae on a vehicle to create fields within a danger zone around the vehicle. The size of each field can be determined by the customer, to suit their specific operating environment and addressing identified risk.

An RFID tag installed on the pedestrian’s cap lamp alerts them – through a light and sound alarm – when they enter this zone. The light changes colour from green to orange and then red, the closer the pedestrian is to the vehicle.

The vehicle itself also receives a warning from the PDS, with the operator being alerted that a pedestrian is in the proximity. If equipped and configured appropriately, the vehicle can also be automatically slowed down at a certain distance from the pedestrian, and similarly brought to a safe stop.

One of the most significant advantages of the Booyco Electronics PDS is that it can effectively detect as many as seven TMMs and 20 pedestrians within one field, in the underground environment.

“Our technology prioritises the safety of the pedestrian in mines, whether underground or opencast,” says Janse van Rensburg. “Our mission is to save lives, and to ensure that every worker returns home safely every day.”

The company’s market leading systems are intrinsically safe, working on a clean 12 Volt power supply that will not ignite methane gas or coal dust. Customers value the complete turnkey solution that Booyco Electronics can provide, says Janse van Rensburg.

“Our combined technology includes a very low frequency (VLF) signal that penetrates rock walls underground,” he says. “This ensures that the pedestrian will still be warned of an approaching vehicle even if it is out of sight around a corner.”

The PDS can be applied to older ‘non-intelligent’ machines on a mine as well as the newer, controller area network (CAN) bus enabled models.

“Our data logging capacity is able to capture all information relating to the interactions between the pedestrians and the vehicles, and also between vehicles themselves,” he says. “This provides the mine with a ‘road map’ to track how any incident occurs, making it easier to report and to improve practices.”

The Booyco Electronics Asset Management System (BEAMS) gives mines the ability to extract useful data on risk areas. This can feed into focused training of staff for more effective safety behaviour.

With 13 years of experience in PDS, Booyco Electronics has supplied in excess of 5 000 sets of mining vehicle equipment around southern Africa, as well as 50 000 pedestrian sets of equipment.

INVESTMENT BY METRIC STRATEGIC CONTRIBUTION TO ENGINEERING CAPACITY

In a boost to South Africa’s engineering capacity and quality, Metric Automotive Engineering has added a new-generation Rottler three-axis CNC machining unit to its workshop. Featuring linear rails for greater accuracy, the machine is the first of its kind in Africa, according to Metric Automotive Equipment operations director Andrew Yorke.

“This technology represents a significant advance in our industry,” says Yorke. “It enables us to conduct wireless probing for measuring and set-up, as well as using CAD drawings to machine components to high levels of precision.”

The scale of the new machine allows it to work on engines up to 20 cylinders in size. The three-axis capacity facilitates the standard machining processes for engine block remanufacture, and also enables salvage repairs. The new unit joins the company’s two larger three-axis machines already in operation. The machines are dedicated mainly to the rail sector.

“A locomotive engine spends considerable time on our machining centres, so our new addition provides much-needed additional capacity for other work,” Yorke says. “On any given day, we can now have up to five V18 engines being machined at our facilities side by side.”

Yorke highlights the value of the new Rottler unit in the continuous quality improvement of local remanufacturing capacity and expertise. As a function of process repeatability and machining accuracy, the quality of output is being constantly raised to the benefit of local customers.

“Our investment in machines like these represents a strategic contribution in support of local original equipment manufacturers (OEMs) and state-owned enterprises (SOEs),” says Yorke. “This fosters the country’s capacity to conduct large engine remanufacturing, which is vital to affordability, economic growth, job creation and conserving our foreign exchange.”

Rottler equipment is not for general engineering purposes but is specifically designed for high-precision machining of engine blocks, he emphasises. This ensures that the quality of remanufactured engines complies in every respect with OEM’s demanding specifications and standards.

The focus of Metric Automotive Engineering’s remanufacturing technology is on large engines used in sectors such as rail, earthmoving, mining, power generation and marine.

IMPROVED DESIGN AND EFFICIENCY TIPS BALANCE TOWARD HV MOTOR REPLACEMENT

The applications knowledge of Zest WEG Group, coupled with the design capability of parent company WEG, now make it easier than ever for old high voltage (HV) motors to be replaced with new, improved HV machines within the customer’s existing footprint and operational configuration.

Compared to HV machines designed 20 to 30 years ago, advances in technology allow for these HV units to often be manufactured smaller than the originals, says David Spohr, Zest WEG Group’s newly appointed business development executive. He works with customers to optimise their HV motor operations.

WEG’s HV motors are typically purpose-built to meet the precise needs of the customer. While smaller in dimensions compared to the original older HV motors, these motors still deliver the required performance at even higher output and efficiencies.

“As a leading technology provider of a wide range of motor products, we have the capability to design a replacement motor to match the footprint of the original unit,” Spohr says. “This means it is not necessary for the customer to modify mechanical infrastructure or electrical design to accommodate an upgraded motor.”

He notes that, with the design lifespan of electric motors which ranges between 20 to 30 years, there are still many old units in operation around South Africa. Technological improvements in motor design and efficiency, however, present a compelling case for the replacement of old units rather than repeated repairs.

Spohr highlights that the cost of a major motor overhaul could be up to 60% of the cost of replacement. The advanced technology of the new units, however, bring important benefits. Key among these are reliability and efficiency, which means improved operational performance and direct savings in energy consumption

“When motor failures occur, Zest WEG Group has the ability to conduct a detailed on-site analysis,” Spohr says. “Based on a root-cause analysis, we can provide a failure assessment which will enable the customer to make an informed decision.”

The assessment includes an energy consumption analysis conducted with specialised software. In the light of the machine’s application, Zest WEG Group recommends enhancements for greater control and efficiency. These include motor control options such as variable speed drives (VSD) for applications such as fans and pumps.

“There are also significant productivity benefits from a new, more reliable motor,” says Spohr. “Unplanned downtime can severely erode plant performance, reduce output and risk supply relationships with customers. All this needs to be considered in the decision to continue repairing old motors.”