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Mining, Process Plant, Maintenance & Safety Training
PERFORMANCE ASSOCIATES INTERNATIONAL
Excellence in Mining, Process Plant, Maintenance, and Safety Training Performance Associates International, Inc. (PAI) is the world leader in online and on-site training for the mining industry. We provide organizations with a single source for assessments, skills training, continuing education, safety training and compliance mandates, and more. Our first-class content guides your staff to gain the critical knowledge they need to work safely and efficiently today. Our proven, leading-edge industrial training programs improve performance in existing operations and ensure success during the start-up of new operations. Our training programs have saved companies millions in personnel accident prevention, production loss, and equipment damage. We partner with our customers and consult collaboratively to provide the analysis and content development to meet your needs. Services PAI Offers Plant Operator TrainingOur three-tier concept for effective plant operator training starts with fundamental knowledge and progresses to plant-specific concepts that are reinforced through detailed animations and interactive simulations. Maintenance TrainingWe custom build state-of-the-art maintenance training programs using exploded graphics, explanatory text, detailed procedures, and management systems. Mobile Equipment Operator TrainingOur first-class training program focuses on operator controls and indicators, safety, and performance optimization. It also includes operating, emergency, and troubleshooting procedures.Commissioning and Start-UpWe can identify, track, and control the thousands of activities that must occur for the successful commissioning and start-up of a process plant. There is no shortcut to a successful start-up.Testing and Tracking SystemsWe can help manage and track the performance of employees to improve the overall performance of the mine and plant industrial training programs. Our testing and tracking systems provide invaluable assistance in safety and operational compliance. Introductory and Safety TrainingOff-the-shelf introductory and safety training packages are an excellent source for mine and plant industrial training courses. They provide fundamental knowledge and basic training concepts. Now offering online courses!E-Learning, Animations, and SimulationsOur interactive e-learning keeps trainees focused and engaged. Our experienced in-house multimedia team develops state-of-the-art graphics, virtual and mixed reality training, stunning 3D animations, and technically engineered simulations of real-world scenarios.Other ServicesWe also provide many services relevant to planning, analyzing, and evaluating process plants, including:·         Operations readiness plan.·         Planning studies.·         Quality management.·         Systems implementation.·         Statistical process control.·         Reliability-based asset management.·         Productive capacity studies.·         Surveys and needs analyses.·         Economic life analysis.·         Process control strategies and methods.·         Debottlenecking and process optimization.·         Spare parts inventory and analysis.·         Feasibility studies.·         Consulting assistance.Consulting * Gap Analysis * Content Development * LMS * On-Site * Train-the-Trainer * E-Learning * Process Plant Optimization * Training * Safety * Mine Training * Plant Operator Training * Maintenance * Mobile Equipment * Competencies * Commissioning
Mining, Process Plant, Maintenance & Safety Training
PERFORMANCE ASSOCIATES INTERNATIONAL
Excellence in Mining, Process Plant, Maintenance, and Safety Training  Performance Associates International, Inc. (PAI) is the world leader in online and on-site training for the mining industry. We provide organizations with a single source for assessments, skills training, continuing education, safety training and compliance mandates, and more. Our first-class content guides your staff to gain the critical knowledge they need to work safely and efficiently today.  Our proven, leading-edge industrial training programs improve performance in existing operations and ensure success during the start-up of new operations. Our training programs have saved companies millions in personnel accident prevention, production loss, and equipment damage. We partner with our customers and consult collaboratively to provide the analysis and content development to meet your needs.  Services PAI Offers  Plant Operator Training Our three-tier concept for effective plant operator training starts with fundamental knowledge and progresses to plant-specific concepts that are reinforced through detailed animations and interactive simulations.  Maintenance Training We custom build state-of-the-art maintenance training programs using exploded graphics, explanatory text, detailed procedures, and management systems.  Mobile Equipment Operator Training Our first-class training program focuses on operator controls and indicators, safety, and performance optimization. It also includes operating, emergency, and troubleshooting procedures. Commissioning and Start-Up We can identify, track, and control the thousands of activities that must occur for the successful commissioning and start-up of a process plant. There is no shortcut to a successful start-up. Testing and Tracking Systems We can help manage and track the performance of employees to improve the overall performance of the mine and plant industrial training programs. Our testing and tracking systems provide invaluable assistance in safety and operational compliance.  Introductory and Safety Training Off-the-shelf introductory and safety training packages are an excellent source for mine and plant industrial training courses. They provide fundamental knowledge and basic training concepts. Now offering online courses! E-Learning, Animations, and Simulations Our interactive e-learning keeps trainees focused and engaged. Our experienced in-house multimedia team develops state-of-the-art graphics, virtual and mixed reality training, stunning 3D animations, and technically engineered simulations of real-world scenarios. Other Services We also provide many services relevant to planning, analyzing, and evaluating process plants, including: ·         Operations readiness plan. ·         Planning studies. ·         Quality management. ·         Systems implementation. ·         Statistical process control. ·         Reliability-based asset management. ·         Productive capacity studies. ·         Surveys and needs analyses. ·         Economic life analysis. ·         Process control strategies and methods. ·         Debottlenecking and process optimization. ·         Spare parts inventory and analysis. ·         Feasibility studies. ·         Consulting assistance. Consulting * Gap Analysis * Content Development * LMS * On-Site * Train-the-Trainer * E-Learning * Process Plant Optimization * Training * Safety * Mine Training * Plant Operator Training * Maintenance * Mobile Equipment * Competencies * Commissioning  
All You Need to Know About: Vertical Shaft Impactor (VSI) Primers
Stedman Machine Company
All You Need to Know About: Vertical Shaft Impactor (VSI) Primers By Eric Marcotte, Inside Sales Manager, Stedman Machine Company Vertical Shaft Impactor What Is VSI? All roads, you might say, lead to the Vertical Shaft Impactor (VSI) because these crushers make it possible to create roadways and just about everything else. Francis E. Agnew of California patented one of the first Vertical Shaft Impactors in 1927. His configuration stacked three VSIs atop each other to produce sand, thus starting the VSI evolution. Today, VSI crushers – and the folks who rely on them – have produced many configurations to include everything from the addition of cascading material into the crushing chamber, to air swept separation of lighter product. One version suspends the shaft from above like a sugar centrifuge. It’s also one of the most feature-patented crushers, so some of the things mentioned here might be unique to a single manufacturer. VSIs apply a large amount of energy to crush material and that’s why it’s one of the most versatile crusher configurations today. View our VSI Machine Specifications, and get a quote today! VSI Benefits When it comes to producing materials such as aggregate for road making, VSI crushers use a high-speed rotor and anvils for impact crushing rather than compression force for the energy needed for size reduction. In a VSI, material is accelerated by centrifugal force by a rotor against the outer anvil ring, it then fractures and breaks along natural faults throughout the rock or minerals. The product is generally of a consistent cubical shape, making it excellent for modern Superpave highway asphalt applications. The rotor speed (feet per minute) controls final particle size. The VSI’s high cubical fracture percentage maximizes first-pass product yield and produces tighter particle size distribution. It has a high-throughput capacity ideal for beneficiation (elimination of soft material). Properly configured the VSI accepts highly abrasive materials. It has simple operation and maintenance. You can quickly change product size by changing rotor speed or cascade ratio. Some models have reversible wear parts to reduce downtime. The VSI typically has low operating costs even in high-moisture applications because of reduced energy costs and low wear cost per ton. VSI Disadvantages There are some feed size limitations with a VSI because of the small feed area available in the center of the rotor. Tramp material in the feed such as gloves, tools, etc. can cause problems with imbalance. The high RPM and HP require careful balance maintenance such as replacing shoes on both sides of the rotor at the same time. High wear part cost may be a problem for some hard abrasive materials, but the VSI may still be the best option. VSI Applications Major limestone applications are for Superpave asphalt aggregates, road base, gravel, sand and cement. Industrial uses include: corundum, corundite, ferro silicon, glass, refractories, silicon carbide, tungsten carbide and zeolite. Mining applications include: bauxite, burnt magnesite, iron ore, non-ferrous metal ore, perlite and trona sulfate. VSIs are excellent for everything from abrasive materials to waste and recycling applications. Verticl Shaft Crushers VSI Crushing Method The VSI is typically used after a primary or secondary crusher. This makes a VSI ideal for making sand and for making coarse and medium aggregates for concrete/asphalt production. Feed size and characteristics will affect the application of a VSI. The feed size is limited by the opening in the center of the rotor. Normally less than 5-inch material is desired, but very large VSIs can handle up to 12-inch feed. Another feature that will affect application is moisture, which can make the feed sticky. Required production capacity is the final limiting criteria. Large primary horizontal shaft impactors can output up to 1600 TPH and more. 1000 TPH is about the maximum for a VSI because of the limiting motor size and the rising G-force of a high-speed rotor, which is calculated by multiplying the radius times the square of the RPM. Shoe configurations are many: rock on rock, groups of rollers, special tip wear parts and many others. The metallurgy of the shoes is also highly varied. Rotors can have three to six shoes. The number of shoes is typically governed by the diameter of the rotor. The larger the diameter rotor, the more openings are possible. Computational Fluid Dynamics (CFD) mathematical models are utilized to simulate the flow and collision forces to reveal solutions for lower wear cost, consistent final product, and higher energy efficiency. The material to be crushed is fed into the center of an open or closed rotor. The rotor rotates at high rpm, accelerating the feed and throwing it with high energy into the crushing chamber. When the material hits the anvil ring assembly, it shatters, and then the cubical shaped product falls through the opening between the rotor and the anvil and down to the conveyor below. The rotor speed (feet per minute) controls final particle size. Speeding up the rotor will produce more fines, slowing it down will produce fewer fines. Feeding Methods Center feed The typical VSI is fed, from above, into the center of its rotor. The material is then flung across an open void to the crushing chamber. It then impacts the outer anvil ring. This crushing action imparts very high energy to the material and is very effective on most types of material. It gives a very uniform and consistent grade of product. Cascade feeding V-Slam Impactors In cascade feeding, material bypasses the rotor and enters the crushing chamber from above. It’s called cascade feeding because as material fills up a large feed bowl, with an outer diameter larger than the outer diameter of the rotor, it spills over the side and falls into the crushing chamber from above, bypassing the rotor. The effect of increasing feed through cascade is similar to slowing the rotor. Cascade feeding in amounts up to 10 percent may have no effect on particle size distribution or quality. The product gradation curve and product shape will change, if an increased amount of cascade feeding is used. Vertical Shaft Impactor for Aggregates (Above: Vertical Shaft Impactor, No Cascade vs. With Cascade Feed, Particle Size Distribution Chart) Rotor and Anvil Configurations The VSI features multiple rotor/anvil configurations for various applications. From open or enclosed rotors to the tubular rotor, each machine is configured for their unique application. In many cases the rotor table, rotor assemblies, anvil ring or rock shelf are interchangeable, allowing maximum application flexibility. Crushers for Aggregate Industry Open top metal rotor shoe on metal anvil The open top metal rotor is good for large feed or medium to very hard material, but it will work best for softer materials. It can handle medium abrasive, dry or wet, but not sticky materials. High reduction ratios are common, which are excellent for sand and gravel production in closed loop systems. Shoe shape can change the production size range. A straight shoe face design produces finer product, and a curved shoe face design produces coarser material. Stedman VSI Impactor Tubular metal rotor shoe on metal anvil The tubular rotor creates higher tip-speeds, which increases first pass yield with tighter particle size distribution and also reduces the recirculation loads. One unique feature is that the rotor rotation is reversible, allowing wear on both sides of the tube. Rotating the tube itself one-quarter turn also doubles the wear. Vertical Shaft Impactor Benefits Enclosed metal rotor shoe on metal anvil The enclosed top plate on a rotor primarily prevents material from escaping from the top of the rotor, which could happen with an overfed open top rotor. Vertical Shaft Impactor Applications VSI Crushers (Above: Rock shelf when VSI at rest. In operation, the brown rock fills the chamber to the upper roof ring. Rock impacts rock in operation.) Enclosed autogenous rock rotor table on autogenous rock shelf Any time the material or rock is used as an impact wear surface the term autogenous is used. Putting a top on the rotor table and shoes allows autogenous use. During operation of the VSI, a bed of material can be designed to build up inside the rotor against each of the shoe wall segments. The bed, which is made up of material that has been fed to the rotor, extends to a wear tip. The bed protects the shoe wall segment from wear. Concerning the rock shelf anvil, it forms a near vertical wall of material upon which the accelerated material impacts. “Rock-on-rock” crushing reduces maintenance but can require up to 30 percent of material recirculation before meeting size requirements. Also, the rock shelf anvil absorbs energy that could otherwise be used for breaking, which may reduce efficiency. More RPM may be needed to achieve the same result as a solid metal anvil. Good for medium abrasive materials, rock-on-rock configurations of either or both rotor and anvil may produce consistent material with low-wear cost and can handle wet but not sticky conditions. Reduction ratios from 2:1 to 5:1 can be expected. It’s widely used for quarried materials, such as sand and gravel. Due to the many configurations of the VSI feed, rotor, anvil and open- or closed- system design; testing is the only way to ensure proper application of a VSI crusher. V-Slam Supplier Summary The VSI is one of the most versatile crushers available on the market today. Even with some limitations, like feed size and output capacity, VSI features have been and continue to be developed to maximize first-pass yields and lower operating costs. If you test your process on full-scale equipment before choosing your VSI, you won’t be disappointed. About the author: Eric Marcotte joined Stedman Machine Company and its affiliate Innovative Processing Solutions in 2010. He has a Mining Engineering Degree from the University of Kentucky.
All You Need To Know About Cage Mills
Stedman Machine Company
All You Need To Know About Cage Mills Cage Mills have a high ratio of size reduction after a single pass through the cages. Here's why, and how. Hands down one of the most versatile size reduction machines and one of the hardest working is the cage mill. There are several varieties of cage mills, but their similarities are more numerous than their differences. They all are internally fed impactors that can crush, grind or pulverize many different materials to specified degrees of fineness. History By 1900, Nathan Stedman had built more than one hundred cage mills designed exclusively to crush coal. Soon other applications were discovered, leading to the increased use of cage mills for crushing such products as chemicals, clay and fertilizer materials. Multiple-row cage mills – two-, four- and six-row -- were commonplace. It was not until the 1930s that the true value of cage mills in the production of agricultural limestone and the crushing and beneficiation of stone and gravel was realized. Cage Mill Pulverizers The cage mill was so popular the Stedman Machine Company became part of farming vernacular -- farmers began referring to agricultural limestone as “Stedman Lime” due to the cage mill's unique capability to create the proper material fineness in just one pass through the crusher. Single-row cage mills were used extensively in the construction of the pioneered Pennsylvania Turnpike, primarily for the beneficiation of aggregates. Beneficiation is an elementary process, but it still is one of the most widely practiced applications of single-row cage mills. Gravel is passed through the mill and the softer, undesirable particles; -- breaking more readily than the harder ones; -- are screened or washed away, leaving a hard, high-quality aggregate. Versatility New uses are constantly being discovered for these versatile workhorses, but the nature of cage mills is such that improvements in them tend to be gradual and evolutionary instead of dramatic and revolutionary. The cage mill can be applied to effectively crush, grind and pulverize a broad array of abrasive and non-abrasive materials, including wet sticky types. The latest technology incorporated in these high-efficiency design mills insures greater crushing capacities, finer grinds and cleaner, safer operation. Fundamentally, cage mills are crushers capable of reducing or disintegrating many kinds of materials to small pieces. They reduce materials solely by impact and range in size from as small as 18 inches to as much as 72 inches in diameter. However, custom units may range as high as 96 inches in diameter. In general, the larger the mill, the lower the cost of operation when measured against tons of output. Operation Cage Mill Size Reduction Equipment A typical cage mill has only one part that moves - the rotor assembly. The material to be crushed is fed into the center of the rotor, or cage, through an intake hopper. The massive bars of the spinning cage aligned in rows strike the material and smash it into particles. The particles are then thrown against subsequent rows, other particles and the cage housing where they impact against breaker plates. Every impact - against cage bar, breaker plate or another particle - tends to reduce the original matter further, into more numerous and smaller pieces. By the time the material finally escapes from the cage mill, it has been thoroughly crushed. The major difference compared to other size reduction methods is the absence of close clearances between the crushing part and the breaker plates, allowing for less maintenance and higher efficiency of the machine. Also, they do not require grate bars as the principal source of impact in the cage mill are the pins of the revolving cages. Impact crushing, particularly impact crushing that uses the most suitable cage mill available, has a number of advantages over compression crushing. Cage mills produce a more cubical product of consistently high quality and they are capable of a very high ratio reduction. There is no decrease in quality of the product even after long periods of operation. Cage mills represent a lower initial investment than most other types of crushing equipment and maintenance is easy and inexpensive to perform. Application Cage Mill Manufacturer The wisest and most effective use of cage mills depends on a proper understanding of them, of how they are made and what they will and will not do. Multi-row mills typically consist of an even number of cages: two, four or six. The cages are arranged concentrically, with each row spinning in the opposite direction from that of the row adjacent to it. Two motors are required. They are mounted on opposing sides of the mill, where they turn in opposite directions. One, two or three rows may be mounted on each shaft. A multi-row cage mill utilizes multiple stages of selective impact reduction. The material to be reduced is fed into the center of the innermost cage, where it is struck by the massive spinning pins and distributed 360 degrees around the cage. Centrifugal force and the impact of the pins causes the material, now reduced to smaller pieces, to pass through the cage into the pins of the next row, which is spinning in the opposite direction. The farther away from the center cage the particles travel, the more their impact velocity is increased. In the process of being thrown from row to row the particles also strike each other. They finally are thrown against tough breaker plates that line the inside of the housing. After many violent strikes against the pins, the breaker plates and each other, the much-reduced particles are caught by the outer housing and allowed to drop through the discharge at the bottom of the housing. Size Control Properly presetting the speed of the cages allows the succeeding rows, moving from the innermost outward, to act principally on the particles that have not yet been reduced to the desired size. Particles that have been crushed sufficiently tend to pass through the subsequent rows without being materially affected. Thus, over crushing or under crushing is effectively controlled by adjusting the speed of the cages. All cage mills are fed internally - - the material to be crushed is dropped into a hopper, from which it travels by chute into the center of the innermost row. It falls from the chute onto the spinning pins of the cage, which strike the falling pieces of feed and explode them into many smaller pieces. The particles are propelled by centrifugal force from the innermost cage into the pins of the adjacent row, which is spinning in the opposite direction. Cage Mills for Aggregates Particles that are still too large are struck by the pins of the second row and reduced further. The reduction process continues through any additional rows that may be part of the machine. The impact velocity of the particles increases as the centrifugal force carries them outward from one cage to the next until they finally strike the mill housing and drop toward the large discharge opening at the bottom of the housing. Controlling the speed at which the cages revolve allows the operator to control the amount of reduction that takes place. That is, if the speed is properly preset and controlled, the material will be reduced to its desired size at some point during its trip through the cage mill and then virtually no further reduction will have to take place. The selective impact crushing that is a characteristic of cage mills minimizes the amount of oversize and undersize particles to be found in the finished product. The design of the cages controls the path that the material will flow through the machine. This makes it possible to concentrate the wear on the pins, which are made of very hard alloys to give maximum possible service before they have to be replaced.
Teamwork Helps Integrate Design, Manufacture and Installation of Size- Reduction Systems
Stedman Machine Company
Teamwork Helps Integrate Design, Manufacture and Installation of Size- Reduction Systems By Eric Marcotte, Inside Sales Manager, Stedman Machine Company Designing and deploying size-reduction systems takes experience. Many people can collect and install some of the pieces they feel are needed to create a working system, but experience with the interrelationships between components is harder to find. And to ensure safety and performance, crushing, screening, storage and handling systems need to be professionally engineered. A system is always more than just a collection of parts; they must work together whether it’s a properly designed chute or an elaborate processing plant. Retrofitting new crushers, conveyors, screens or other pieces of equipment is also not always an easy process. Even if drawings and specifications no longer exist, plant designers need to make sense of what is there and know what it takes to make new pieces fit in an existing puzzle. If continuing production during the upgrade is required, system bottlenecks will need to be prevented. For example, raw material or finished product stockpiles may be required to keep downtime to a minimum. Also, access and space requirements need to be confirmed and double-checked. First - Assemble a Team Engineering and expertise in a variety of areas are required to develop size reduction systems, including: crushing, screening, structures, conveyors, chutes, hoppers, dust collection and storage, whether for a small equipment retrofit or a large turnkey facility. CAD and process design software applications are must have. Limit multiple layers of personnel. Work directly with the engineers and personnel to select the equipment and design the system. Project management, installation, scheduling and tracking experience will be needed. Be sure supervisors and installers are MSHA trained and have experience in fieldwork. Second - Process Design While most projects present new challenges, a widely experienced team will bring in ideas from other industries. Typical projects involve the following processes and types of equipment. industrial crusher Load out and material receiving This can be a feed hopper with an apron feeder, belt feeder, vibratory or screw feeder, truck dump or railcar unloading system. Bulk material transportation Designing, building or procuring belt conveyors, stackers, apron conveyors, screw conveyors, and pneumatic handling conveyors. Crushing Crushing is the basic building block of a size-reduction system. Experience with a large range of crushing equipment offers many solutions. Properly feeding material into the crusher greatly increases its efficiency, contributes to even wear and maximizes wear metal costs. Bulk material storage Specifying, providing and installing a range of silos, hoppers or other bulk storage solutions. aggregate crusher Screening Experience with many screening manufacturers to include the right screening solution into the system. Dust Collection Including the proper dust collector and dust collection system is a key component to allow a crushing system to work properly. Experience with many dust collection vendors will facilitate properly sizing, connecting and installing the best dust-collection system solution. Controls and Electrical Components To make sure that all components of a system work together, work with control system engineers, panel builders and electrical contractors to create a working, integrated system. Buildings, Foundations and Structure Design, procurement and specifications for buildings, foundations and structures for the equipment supplied on any system. Third - How to Do It Every project has a different set of circumstances that are unique to it. Try to follow a simple checklist to ensure the best possible solutions to the problems. Initial project team meeting. Crusher and screening testing as required. Define required scope for the system. Create preliminary concepts and drawings. Review with operators and supervisors. After receiving feedback, fine-tune the drawings, concepts and put forth a detailed proposal. Set up kick off meetings as required. Proceed with the purchase of major components. Proceed with a detailed system arrangement. Detail major assemblies. Assemblies put out for detail drawing creation. Drawings are self-checked and then crosschecked for accuracy. Assemblies are re-entered into system layout from detail assemblies to verify fit. Approval drawings sent out as required. Vendor drawings checked and approved. Items checked as they are received. Work with vendors and shipping to verify shipment accuracy. Pictures are taken of all shipments for record purposes. Installation supervisor works with install crew to identify, locate and erect items as needed. As installation finish date nears, begin check of motor rotations, sensors etc. Final customer acceptance – formal reviews to finalize “punch list,” follow up items and document the system is performing as specified. Example - Typical Quarry Expansion A limestone quarry running since the 1950s and producing 500,000 tons per year wanted to increase yearly production capacity up to 1.5 million tons with a new automated plant. The new design needed to have the capability to stockpile hundreds of thousands of tons of finished product. The focus was on creating a state-of-the-art plant with designed-in flexibility to do different product sizing. The automated plant needed to have the ability to run production all day as well as to be able to change the product sizes within 10 minutes. The design and fabrication of a new plant may take up to two years to complete as each idea is considered and "wish lists" are sorted out. You don’t want to come back and say we should have done this or done that. Get the very best of everything you can get into the plant for longevity. The project will include numerous conveyors, sensors, controls, vibrating screens, feeders and other equipment. size reduction machine Installed electronics and control systems feed a programmable logic controller. Each conveyor at the plant is equipped with terminal strips that are all wired to communicate information to one main processor, bringing all of the information together in one place to make it easy to operate. All of the feeders and conveyors are monitored to collect all of the information required to operate the plant. With the ability to monitor the speed of the conveyors and feeders, the quarry can keep an eye on production and troubleshoot maintenance issues. The reason for having an automated control system is that if something goes wrong on one of the conveyors, you’ll see it fast enough to prevent a catastrophe that might require digging out a conveyor. If something does go wrong, the computer can take over and begin dropping conveyors, discharging material and shut the feeder down. Since the quarry can now monitor the conveyors moving, the speeds and the tons per hour, limitations can be set to help catch problems before they become too serious. If something is going wrong, say conveyor 2A is slowing down, you can put limits on how much you want to allow it to slow down before the feeder is paused and then limit how long that feeder stays paused. In the end, the quarry was able to more than double their production capacity with the help of the automated plant. The plant was built, delivered and installed as planned with no problems. This is an ideal situation if a quarry is sitting on huge reserves of limestone and plans to operate the crushing plant well into the future. Projects such as this are successful when the customer’s needs are defined and understood, and the project team – including the customer and all supplier partners work to accomplish the project goals.
Expect More from your Horizontal Shaft Impactor
Stedman Machine Company
By Eric Marcotte The mineral processing industry usually evolves rather than revolutionizes, but the Horizontal Shaft Impactor (HSI) has revolutionized the crushing process in numerous industries.32 IMPACTOR 400 There are several varieties of the HSI, and their similarities are more numerous than their differences. All varieties feature externally fed horizontal rotors with breaker bars, which propel material into a series of apron-mounted breaker plates that crush or pulverize many different types of materials to specified degrees of fineness. In 1946, Dr. Erhard Andreas of Muenster, Germany, patented the “Andreas Impact Crusher System.” His design utilized old torpedo tubes and steel from decommissioned tanks. Since then, there have been many unique features of the design patented, but they all operate similarly. This article reviews current techniques employed to get the most from this versatile design. Versatility Reduction ratios of up to 30:1 are achievable in a single stage. The simple design offers low capital and operating cost. Low headroom requirements make it easy to install. Product sizes may be varied by changing rotor speed and the clearances between rotor breaker bars (also called blow bars or hammers) and apron breaker plates. HSI applications have gone beyond soft and nonabrasive materials such as limestone, phosphate, gypsum and weathered shales, to harder minerals thanks to the introduction of alloy steel rotor breaker bars. Typical alloy steels contain manganese and/or high or medium chromium content. There are many different crushing chamber designs on the market, and proper selection will depend on the knowledge of the application for proper feed, crushing chamber configuration, metallurgy of the crushing chamber components, gap setting and rotational speed. Finally, computer controls can automatically adjust HSI settings on the fly to adjust for wear or changing specs. Operation HSIs have a lined crushing chamber with rotating breaker bar rotor on a horizontal axis. The size reduction takes place quickly along short fracture lines, producing a more cubical product to meet aggregate specifications. This fast impact fracture is different from the slow compression breaking in cone or jaw crushers that produce more slabby or flat material (5:1 length to height ratio). 32 IMPACTOR2 400Feed enters the primary crushing chamber and meets the rotor breaker bars, which impel the feed against the first apron lined with breaker plates. Impact with the rotor, the breaker plate, and inter-particulate collision all contribute to comminution. Material is reduced in the primary chamber and passes by the front apron breaker plate gap, entering the secondary and, in some configurations, tertiary chambers, for final reduction. A high percentage of the initial size reduction comes from the first impact with the rotor breaker bar. Aprons are shaft suspended at the front and from a spindle in the rear, allowing for continuous gap adjustment as wear progresses. Unlike hammer mills, the open discharge impactor has no screens or grates holding material inside the crusher; material is efficiently processed at high rates for low costs. The rotor breaker bars operate best at specific speed ranges for maximum results. As the total processing capacity and rotors get larger, the number of breaker bar rows increases. On smaller sizes, there are only two rows; on larger rotors, there are four or more rows of rotor breaker bars. The optimum configuration has material delivered to each row of rotor breaker bars in a continuous bed over the width of the rotor for optimum performance and consistent wear part utilization. Some rotor interiors are open, and some are closed depending on feed conditions. For example, concrete recycling requires a closed rotor so rebar doesn’t get entangled. Application The HSI is used for all types of material with compressive strength less than about 20,000 lb. per sq. in. It’s widely used for sand and rock for roads, railways, reservoirs, electrical grid isolation, building materials and many industrial applications such as metal reclamation and recycling.34 IMPACTOR3 400 Wear part metallurgy is critical to proper applications and performance. It’s a good idea to keep a log of these items to determine the best wear part selection and maintenance schedule: feed and discharge information, throughput rates, change out records and measurements of worn parts. Proper selection of wear part metallurgy will result in optimum production rates; longer maintenance cycles and fewer changeouts, which reduce costs in labor, increase the wear part’s life as well as reduce downtime. Materials with high moisture content can be successfully handled by using heaters and air cannons to reduce and dislodge material adhering to the crushing components and chamber. Size Control The spacing between rotor breaker bars and breaker plate aprons can be adjusted to produce different products within one crusher. It is possible to crush soft raw material limestone or high-grade harder limestone for cement or asphalt applications with one crusher by externally adjusting the breaker bar and plate settings. Gap adjustment between the rotor breaker bars and breaker plates by manual or computer controlled systems adjusts the crushing gap so that product particle size distribution remains constant. Maintenance HSIs have multi-turn breaker bars for extended life before changeout. Design simplicity offers safe and easy access for breaker bar replacement and access to all areas of the crushing chamber. Front-opening models eliminate the need for a crane in some cases. Rear-opening models can allow unique installation applications. Summary 34 IMPACTOR 400 HSIs have evolved from humble beginnings through improved crushing chamber design and metallurgy advancements to automation controls. HSIs have proven they are capable of size reduction of all types of material sizes and hardness with minimal maintenance and excellent cubical particle size distribution control. Stedman Machine Co., www.stedman-machine.com Eric Marcotte is inside sales manager for Stedman Machine Company
Gold Mill Grinding—Example of a Detailed eLearning Operator Training Module
PERFORMANCE ASSOCIATES INTERNATIONAL
This video provides an example of the content and structure of a Performance Associates International computer-based operator training program. In this video, we focus on the user experience of our eLearning module for operators in a gold mill grinding circuit. This example demonstrates the following program features: • Language toggle controls. • Interactive process flowsheets. • Process descriptions. • Principles of operation. • Workbook feature. • Equipment (SAG mill) 3D animation. • Process variables. • Control loops. • Interlocks. • Alarms. • Interactive plot plan. The grinding circuit is just one of 11 modules included in the complete plant operator training program. Each individual module covers the technical aspects of a specific plant area. The program also contains modules presenting basic introductions to many applicable unit operations and a variety of basic mechanical skills. Additionally, detailed maintenance training modules cover each significant piece of equipment in the plant. A comprehensive training component to develop supervisory skills is included as well. Building, running, and maintaining a new plant is a significant investment. A work-force well-trained from top to bottom is the best way to protect that investment by ensuring a successful start-up and continued operations at peak performance. If you are building a plant and preparing your operators and supervisors for start-up and operation, please stop and ask the question “what components of this training program do I NOT want my operations team to be thoroughly familiar with?”