Higher production demands across all stages of bulk shipping require increased efficiency at the lowest operating costs, in the safest and most efficient manner possible. As conveyor systems become wider, faster and longer, more power and better control capacity will be required. To this, we must add increasingly stringent environmental regulations and plant managers who understand the costs will closely look at how new equipment and designs match. with their long-term goals to achieve the best return on investment (ROI).
Safe with higher conveyor speeds
Safety is likely to become a new source of cost reduction. The percentage of mines and processing facilities with robust safety systems is likely to increase over the next 30 years until it becomes the norm, not the exception. In most cases, with just a small adjustment of conveyor speed, operators quickly detect unexpected problems in existing equipment and keep the workplace safe. These incidents are typically identified by larger spills, increased dust emissions, ice deflection, and more frequent wear/equipment failures.
More material transported on ice can cause more material to spill and hover around the system, which can present a tripping hazard. According to the US Occupational Safety and Health Administration (OSHA), falls account for 15% of all workplace deaths and 25% of all workplace injury claims. .1 Furthermore, higher ice speeds make constriction and tilt points on the conveyor more dangerous, as reaction times are dramatically reduced when a worker becomes trapped by clothing, tools or limbs. due to random collision.2
Figure 1: When the conveyor is not properly loaded, the weight of the material conveyed is lighter towards the load. ® Martin Engineering 2022.
The faster the conveyor belt runs, the faster it deviates from its travel and the harder it is for the belt tracking device to compensate, causing material to overflow along the entire conveyor route. Caused by improperly centered conveying, jammed belt rollers or other factors, the conveyor can quickly come into contact with the main frame, tear off the edge and potentially cause a fire. Friction. In addition to the workplace safety consequences, conveyors can carry fires throughout a plant at extremely high speeds.
Another hazard in the workplace, one that is increasingly being regulated more closely, is dust emissions. An increase in material conveyed means more weight at higher conveyor speeds, more vibration on the system and reduced air quality due to dust. In addition, the cleaning wiper efficiency tends to be reduced as the amount of conveyed material increases, causing more airborne dust emissions during the return journey of the conveyor. Corrosion particles can adhere to moving parts and cause them to become trapped, increasing the potential for frictional fires. It also increases maintenance costs and causes downtime. Furthermore, poorer air quality can result in fines and inspection being forced to shut down equipment.
Eccentric alignment before that happens
As conveyor belts get longer and faster, modern monitoring technology becomes imperative, with the ability to detect slight changes in conveyor travel and quickly compensate before weight, speed and force. drift can bypass the monitoring device. Usually installed on the return stroke and the load sides for each 20 - 50m segment - before the unloading pulley on the feeding side and the end pulley on the return side - upper and lower tracking devices use the technology innovative multi-torque, multi-spindle with a directional sensing boom assembly that detects slight changes in the conveyor route and immediately adjusts the flat rubber single tension roller to bring the conveyor back on straight position.
Figure 2: Design of a roller with a brake guide that holds the conveyor belt and uses resistance to bring it back into alignment.
Modern drainpipe design
To reduce costs per ton of material transported, many industries are turning to wider and faster conveyors. The traditional trough design will likely remain the standard design. However, with the shift to wider and higher-speed conveyors, block processors will require significantly more reliable components, such as tension rollers, impact-resistant supports. and discharge pipes.
A major problem with the most standard drain hose designs is that they are not designed for growing production needs. Unloading material from the conveyer pipe onto a fast-moving conveyor can divert material in the discharge pipe, causing the load to become eccentric. This increases the spillage, causing the material to float and cause dust generation after leaving the settling area.
Newer conveyor tube designs concentrate material in the center of the ice in a well-sealed environment, achieving maximum throughput, limiting spills, reducing airborne dust and minimizing risks of damage. common injuries in the workplace. Instead of falling material hitting the conveyor directly, the lowering of the material is controlled to increase conveyor durability and prolong the life of the impact support and tensioning rollers by limiting loading forces. of material in the loading area. Reduced turbulence favors wear-resistant linings and edge guards and reduces the risk of suspended material getting between the fender and conveyor belt, which can cause friction damage and cause ice fraying. load.
Figure 3: Modern static zone performance components are designed to reduce maintenance and improve safety.
Longer and taller than previous designs, the modular static zones give the material time to settle, giving more space and time for the air to slow down, so more dust settles. Modular designs easily adapt to future capacity changes. The outer wear-resistant lining can be replaced from the outside of the discharge pipe, instead of requiring access to the inside of the hazardous discharge pipe as in previous designs. The drain cover with internal dust screens controls the downward flow of air along the length of the duct, causing dust to accumulate on the screens and eventually fall back onto the conveyor in larger clumps. And dual flanged seals with primary and secondary seals in a double-sided elastic band help prevent spillage and dust escape from the discharge hose sides.
Reconsider conveyor cleaning
Faster ice speeds can also cause higher operating temperatures and damage the cleaning wipers. Larger amounts of material approaching at high velocities hit the main wipers with greater impact force, causing some structures to wear out rapidly and resulting in more feed back and increased spillage. out and the amount of dust dispersed increases. In an attempt to compensate for reduced equipment life, manufacturers can reduce the cost of ice cleaners, but this is an unsustainable solution as it does not eliminate additional downtime. involves frequent cleaning and changing of the wipers.
As several wiper manufacturers are struggling to keep up with changing production needs, industry leaders in conveyor solutions have reinvented the cleaning machine industry by providing High-strength polyurethane (PUR) wipers are made to order and cut in the field to ensure the latest and most durable product.
Using a torsion, spring or pneumatic tensioner, basic cleaners bypass conveyors and joints but are still highly effective at removing return stuff. For the largest power applications, the basic cleaner design consists of a combination of tungsten carbide vanes installed diagonally to form a three-dimensional curve around the head pulley. Field Service has determined that it typically offers up to 4 times the service life of basic urethane cleaners, without the need for re-stretching.
Figure 4: Single-core generator with enough electrical power to run a variety of accessories.
When using tape cleaner technology in the future, an automated system will increase wiper life and belt durability by eliminating wiper contact with the tape whenever the tape is removed. load idling. Pneumatic tensioners are connected to the pneumatic system and are equipped with sensors to detect when the conveyor is idling and automatically retract the wiper, minimizing unnecessary wear. for both tape and cleaning equipment. In addition, it also reduces supervision and frequent tensioning of the lever to ensure maximum efficiency. The result is consistent maintenance of standard wiper tension, reliable cleaning performance and longer blade life, all efficiently managed and without operator intervention.
Systems designed to operate at high speeds over large distances are generally supplied with power only where necessary, such as the head pulley, regardless of the power required to power “intelligent systems.” self-propelled, sensors, lights, accessories or other devices along the length of the conveyor. Running auxiliary power can be complicated and expensive, requiring transformers, cable ducts, junction boxes and oversized cables to accommodate the inevitable voltage drop over time. prolonged activity. Solar and wind power can be unreliable under some environmental conditions, particularly in mines, so operators need reliable alternative power generation facilities.
By fitting a small patented generator to the belt tensioners and utilizing the kinetic energy generated as the belt moves, accessibility obstacles are encountered in powering the systems. backend is now fixable. Designed to be stand-alone power stations that can be retrofitted to existing tension roller support structures, these generators can be used on almost any steel roller.
The design uses a magnetic coupling that attaches a 'drive ratchet' to the head of an existing roller, which matches the outside diameter. Rotated by the motion of the belt, the drive ratchet is connected to the generator through the machined drive tabs of the housing. Electromagnetic bonding ensures that electrical or mechanical overload does not force the coil to stop, rather that the magnets will dislodge from the winding surface. Thanks to the generator placement outside the feed line, this new design avoids damage caused by heavy loads and floating fuel.
Transport of bulk materials, safety and automation in the future
Automation is the solution of the future, but as experienced maintenance workers retire, younger workers doing the job will face special challenges, with maintenance and safety skills is becoming more and more complex and necessary. While basic mechanical understanding is still required, new maintenance personnel also need to have a more advanced technical understanding. This division of work requirements will make it difficult to find people with a wide range of skills, cause operators to outsource some specialized services, and make maintenance contracts more common.
Conveyor monitoring for safety and preventive maintenance will become increasingly reliable and widespread, helping conveyors automatically operate and predict maintenance needs. Finally, professional autonomous vehicles (robots, drones, etc.) will take on some dangerous jobs, especially during underground mining because of ROI for safety. all further adjustments are made.
Ultimately, the inexpensive and safe transportation of large quantities of bulk materials will lead to the creation of many new and more productive semi-automated bulk feeders. Formerly supplied by trucks, trains or barges, the long-overground conveyors that transport raw materials from mines or quarries to storage or processing facilities can even impact to the transport sector. Reaching great distances, this long bulk carrier network has been built in some places with poor accessibility but may soon become ubiquitous in many parts of the world.
R Todd Swinderman, CEO Emeritus, Martin Engineering
Nguyen Thi Kim Lan translated from Global Cement Magazine February 2022 issue
Source: Vietnam Cement Association
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