The Stedman V-Slam™ is the vertical shaft impactor for all your coarse-to-fine crushing needs. It offers significant savings over higher-priced competitive crushers. The V-Slam, with its low horsepower per ton of throughput, minimizes operating costs. Our vertical shaft impactors feature multiple rotor configurations for various applications. From open and enclosed rotors to the Stedman Patented Tubular Rotor, each machine is configured to provide customers exactly what is needed for their unique application.The V-Slam has a wide speed range as well as the highest rotor tip speed allowing a high degree of process control.The new Patented Tubular Rotor provides many benefits over the standard shoe and anvil designs as well as rock-shelf applications. The easily replaceable and indexable rotor tubes, cut your total operating cost and maintenance time in half, making V-Slam the easiest VSI to maintain and one of the best impact crusherson the market.Vertical Shaft Impactor ApplicationsLimestoneSand & GravelGlassFerro Silicon & Silicon CarbideAluminum Dross & Other SlagsBurnt MagnesiteTungsten CarbideTrona SulfateBariteBakery WasteZeoliteand much more...Click here for information on retrofitting your existing VSI to the NEW Stedman Tubular RotorGive Your Materials a Spin in our Test Facility VSIThe Stedman Testing & Toll Processing Facility is the place to test your material in our full size VSI. If it can be crushed, ground, pulverized or mixed, chances are we’ve done it. We have more than 10,000 test reports to help get you to the best solution quickly. To learn more about what to expect from testing, read this article that ran in POWDER BULK ENGINEERING magazine.

A solid performer since its ground-breaking introduction, the Stedman Mega-Slam horizontal shaft impactor effectively handles large feed sizes - beyond the range of secondary HSI crushers. Horizontal Impactor ApplicationsAluminum DrossAsphaltBrickGravelLimestone Impact Crusher Lead SlagShaleClick here for more applicationsMega Slam Features and BenefitsReduction ratios up to 20:1360° Bearing contact = long bearing lifeFeatures 2” thick housing linersSolid Rotor with 3 or 4 breaker bar rowsDependable product control and rugged wear partsManual or power assist apron adjustmentMax-Yield™ automatic apron adjustment systemMega-sized processing requires more than guesswork.Stedman’s unique, full scale Testing and Toll Processing Facility takes the guesswork out of selecting particle size reduction technology and equipment. Contact Stedman to schedule your testing in our full-size HSI. To learn more about what to expect from testing, read this article that ran in POWDER BULK ENGINEERING magazine.

Impact size reduction incorporates striking to pulverize material. The primary types of impact crushers include -- horizontal shaft impactors (HSI), cage mill pulverizers, and vertical shaft impactors (VSI). Each impactor can be further designated as primary and secondary rotor crusher as well as tertiary and quaternary crushers. This particular designation is dependent on which processing stage the equipment is being utilized. Crusher Throughput ProductionFeed enters the crushing chamber and meets the breaker bars or plates propelling feed against the breaker plates resulting in impact reduction. There are no screens or grates holding material inside impact crushers, so material is efficiently processed at high rates for low costs.Secondary Impact Crush ApplicationsLimestoneGravelClay & ShaleFrac SandCoalSlag (Aluminum Dross, Copper, Steel, etc…)Fired ClaysRAP – Asphalt recyclingConcrete without RebarFloor Tile GlassConcrete BlockStone CrusherResidential, Commercial & Paving BricksGranite

Get More Performance Out Of Your Crusher impactor maintenanceThere’s an urban legend out there about the company whose maintenance crew mistakenly installed a new crusher with the rotor spinning backwards. It still worked! And you think you have issues? To get the most from your equipment investment, you need to put in the time. Yes, a crusher costs a bit more than your average automobile, but that doesn’t mean it’s maintenance-free. An automobile needs oil changes too, right? Performing regularly scheduled maintenance on impact crushers is crucial for guaranteeing day-to-day reliability and optimum product output. Did you know you can boost output and quality by doing just a little bit more? Even daily cleanups and inspections can increase service life. It’s a no-brainer, though possibly easier said than done. Here are some steps and practices to incorporate in your ongoing operations and maintenance. Beginning with maintenance team education, parts logs, and general maintenance record keeping, plus troubleshooting, these guidelines will help your crusher go the distance. Training: Proper training for consistent maintenance is one of the most fundamental requirements for successful, reliable production. Begin with the crusher’s operation and maintenance manual. Incorporate the manual’s suggested routine maintenance schedule into the maintenance team’s duties. Appoint a “lead person” for each crusher as the go-to for that machine. This person is the historian for the unique operational adjustments the producer has incorporated for raw feed and product requirements. Daily log (document the following every 8 hours): Amperage draw: See if it changes from day to day. If amperage is exceeding normal levels, it could be a signal of bearing problems, loose belts, or general feed issues. Coast-down time: You’re going to need to know (and log) how long it takes the machine to come to a complete stop after shutdown. Here’s why: If the time starts to shorten, this could indicate a bearing problem. Oil pressure: You’ll want to record performance in a variety of operating conditions. This will allow you to identify trends and help to detect problems before they cause costly damage or downtime. Daily maintenance (every 8 hours): Check oil level, sight glass, grease appearance, and other lubrication schedules. Check high temperature or low hydraulic pressure indicators and switches. Check wear parts. Tighten bolts. Inspect belts. Remove dirt and debris from crusher frame surfaces and areas around the machine. Check intake/discharge chutes for any obstructions and/or build up. Check alarms. If electrical changes are made or programs are altered in automated systems, verify that all alarms and interlocks function properly. Don’t be afraid to replace switches or timers that appear damaged or are in poor condition. This is more economical than a major overhaul, but never disable or alter any alarms or interlocks! Lubrication: Completely drain and thoroughly clean out the inside of the oil tank (if you have one) to eliminate any contaminants before refilling. Find contaminant sources. Contaminants such as dust particles and water can get in where oil leaks out. Inspect hydraulic systems and tag any leaks for corrective action on the very next maintenance cycle. Use the proper grade of oil. Use the proper specification of filters. Keep the oil breathers clean. Understand grease versus oil lubrication. Grease requires less-intensive maintenance than that of oil-lubricated systems. Automatic oil lubrication systems or sealed cartridge bearings are for higher speed crushers like vertical shaft impactors, air swept fine grinders, or high-speed cage mills. Most horizontal shaft impactors, hammer mills, and cage mill applications are below 1,000 rpm and grease is sufficient. Maintain a scheduled oil sampling program. By creating a baseline of normal wear, it helps indicate when abnormal wear or contamination is occurring. The exact condition of a mechanical assembly is reflected in the oil. Belts: Inspect V-belt drives for damaged belts or loose belt tension. By replacing cracked, glazed, torn, or separated belts, plus maintaining proper belt tension, you’ll optimize your plant’s performance. Wear parts: Don’t overextend wear parts. Avoid running them so long that they become too worn. You may find that you can no longer rotate breaker bars or interchange wear plates to lower wear areas — and now, you’ve lost half of the wear. Guards: Rubber and chain curtains located in the feed and discharge openings of the crusher are subject to wear and tear. Since they are a first line of protection, it’s important to inspect them regularly and to establish a schedule of regular maintenance. Electrical: When (or if) electrical changes are made, you’ll need to verify that all alarms and interlocks still properly function. Same goes for programs when altered in automated systems. Always check with the manufacturer before making any modifications. Spares recommendation: Keep the recommended spares on hand and order replacements as soon as they are used. A list of recommended spares may be included with your equipment operations manual. If not, contact the manufacturer for recommendations. Update your equipment: All equipment evolves, and the recommended manufacturer upgrades are a good investment for increased life and better crusher performance. Check with the manufacturer for any possible updates. Unapproved modifications: Manufacturer design engineers have considerable field experience, which helps them as they calculate the design and perform prototype testing. Their engineering tasks include calculating bearing loads and bearing clearances. They’ve also worked to maximize throughput by establishing the most efficient speed and setting combinations to optimize impact on the material undergoing reduction. So when plant personnel suggest modifications that alter the intended design, these changes will more than likely hurt the purpose of the original design. As a result, you’ll have a less productive and reliable crusher due to potential damage and overload. Since the manufacturer has a vested interest in how well the crusher performs, contact them before making any modifications Cage Mill Operation and Maintenance Requirements for optimum production and wear part utilization include the following: sleeve wear patterns cage wear pattern identification To increase multi-cage sleeve life, cage rotation should be reversed regularly, if possible. (Some cage mills can be reversed, while others cannot.) By reversing the cage direction, sleeves will be worn from both sides, thus extending wear life. Wear parts: Index and or replace sleeves periodically. Inspect or replace hopper ring and shaft protector, if needed. Cage rebuilding is an option. Bearings: Follow the manufacturer’s recommended specifications and schedule for lubrications, temperature, and vibration ranges of spherical roller bearings in pillow block housings. Horizontal Shaft Impactor Operation and Maintenance Variables affecting product gradation include the following: Rotor speed – Higher rotor speeds produce finer product output.Breaker bar wear & new edges crush finerBreaker bar changes. Apron gap settings – Closer gaps retain the feed longer producing a finer product. Breaker bar wear – Regular inspection and turning will lower operating costs. Throughput (tons per hour) – Overfeeding a crusher can make the output more coarse, but it also causes a number of wear and longevity issues making overfeeding a major concern to avoid. Moisture – Moisture cushions the impact, producing a coarser product. Apron wear – Worn plates can be replaced or moved to areas of lower wear. Spring bridge operation – Spring set height is critical to maintain proper operation of spring bridges. Spring bridges return the aprons to their original positions after an overload situation. The use of altered or non-specified springs can cause equipment damage or catastrophic failure. Requirements for optimum production and wear part utilization include the following: Protect inlet and outlet. Restrict maximum feed size. Maintain feed rate within allowable limits. Check rotor rotation. Use metal detection (required). Check for wear. Follow recommended breaker bar rotation setting sequence. Check rotor breaker bar, wedge, and stop block or jack screws. Check liners and breaker plates. Vertical Shaft Impactor Operation And Maintenance The vertical shaft impactor uses high rotor speeds (1,000 to 3,000 rpm) to apply high energies to the material, and since Energy + Material = Size Reduction, it can create sand from 2-inch feed. Requirements for optimum production and wear part utilization include the following: optimized parts in rotor tube Limit feed size. Use metal detection (required). Observe any vibrations with the use of continuously monitored vibration sensors. Listen to the equipment, if something sounds unusual, shut down and inspect. Limit recirculating product in a closed system. If using water for dust suppression, introduce it into the discharge area if possible. Introducing water in the intake will increase wear. Place weight match shoes opposite one another. The image above shows rotor tubes indexed 90 degrees providing a new wear surface. Wear parts include the following:recommended parts for vertical shaft impactors Shoes and tubes Anvil ring or other inserts Housing liners Rotor table liners and assembly Spares recommendation: Shoes (one complete set) Table liner Anvils (one complete set) Discharge plate The spare parts inventory shown above is recommended for vertical shaft impactors. Hammer Mill operation and Maintenance Up running hammer mills combine impact and shear to reduce material. Down running hammer mills primarily use shear by immediately taking feed to the screen or grate bars where hammers shear the material, until it passes through the openings. Requirements for optimum production and wear part utilization include the following: Lubricate bearings regularly. Regularly inspection (unclamp or unbolt front upper half housing for access to screens and hammers) liners, hammers, hammer bolts, rotor discs, grate bars, and screens. Spares recommendation: Hammers Screens Liners Grinding plate Summary A partnership begins between the manufacturer and the customer when the crusher is installed in the field. The manufacturer needs the customer’s help as much as the customer needs the manufacturer’s help to achieve the highest performance possible. Maintenance service after the sale, although mentioned last, is a central part of crusher system performance. And just in case, the manufacturer will have the people and the parts available 24/7 to assist with any problems. Regardless of the field application, the training of personnel is key to successfully and optimally operating equipment. For the size-reduction industry, crusher maintenance problems are mostly related to inadequate training. This exists at plants both large and small. The most effective education is a current and ongoing program for crews — and that’s what will result in legendary performance.

New plant, automation system double operation’s production capacity By Loretta Sorensen| November 10, 2017 Four generations of the Duff family have overseen quarry operations for the past 67 years at Duff Quarry Inc. in Huntsville, Ohio. Among the reasons for their long-term success is a focus on high-quality, economic throughput. “That’s one of our focal points,” says Ross Duff, vice president. “For the past 10 years, automation has allowed us to maximize safety, improve ease of maintenance and have direct oversight of material quality.” Photo courtesy of Duff Quarry Duff Quarry was bare farm ground when the late C.E. Duff purchased it in 1950. Its abundant limestone deposit runs about 400 ft. deep and covers around 400 acres. Today, with three locations, Duff Quarry includes Ohio Ready Mix and Mr. Concrete Builders Supply, employing more than 60 people in Huntsville, Russells Point and Bellefontaine. Customers come from within a 25-mile radius of Huntsville. New era The Huntsville quarry contains bluish-gray dolomitic limestone, which is ideal for construction materials like concrete and asphalt production, the company says. Upper layers of the quarry’s limestone deposit have a high magnesium content, giving the stone a reddish hue. Lower limestone layers, in laminated sheets, are dark gray. The quarry’s limestone is crushed and used in a number of construction projects, including private and business drives in the area. Duff Quarry customers also purchase a variety of crushed limestone products, riprap, concrete sand, mason sand and gravel. In 2005, when Duff Quarry was responding to increased product demand, it purchased a new limestone crushing plant from Stedman Machine Co. At the time, Duff was updating the plant it had used since 1956, seeking equipment that would offer flexibility with product size. The Duff family first learned about Stedman around 1956, when it purchased a Stedman 48-in. four-row cage mill to process agricultural lime at its old quarry. In 1994, Duff purchased a Stedman Mega-Slam crusher for a different location because the company believed it was a superior crusher with its portable plant. Over two and a half years, a Stedman affiliate, Innovative Processing Solutions, designed and fabricated the new automated system, which utilized Stedman’s 5460 Mega-Slam and 6460 Grand-Slam size reduction impact crushers. Innovative Processing Solutions specializes in custom solutions for bulk material handling systems, using equipment from Stedman and other manufacturers to create a variety of systems. The extended system design timeframe gave the Duff family the opportunity to develop a system that can serve them for many years. “We bought the plant in 2005, installed it ourselves and completed construction in 2007,” Ross says. “It was more than 95 truckloads of steel. Apex Engineering set up our automation. The plant uses twin Stedman impact crushers, a Deister grizzly feeder, scalping screen and twin finish screens.” Twelve employees kept the old plant running while the new plant was designed and installed. Prior to installing the new system, the quarry’s annual processing average was about 600,000 tons of limestone. With the new system, production averages 1.5 million tpy when running at full capacity. Customized crushing From left: Plant Operator Jason Beecraft, Mine Foreman Bill Page, President J David Duff and Vice President Ross Duff. Photos courtesy of Duff Quarry The quarry’s automated system includes a fiber linked A. B. Rockwell PLC system run by redundant Windows-based computer control rooms. Quarry operators manage the automation by utilizing an application that runs through two iPads. The system is set up so only one iPad can make system changes at any one time. The plant operator can access the automation system from anywhere on the mine site. “When we designed our plant, we wanted to avoid having our plant operator watch quarry activities from a remote control room,” Ross says. “Using the iPad allows the plant operator to have direct oversight of material quality and make immediate changes as necessary. “It also eliminated the need to contact the person in the main control center,” Ross continues. “A delayed response is not always the safest way to operate. If the plant operator is right there they can stop or start the plant and inspect any equipment to identify maintenance needs.” The iPad used to control the system uses a WiFi signal generated by a router installed in the quarry. Signal strength can vary but is always strong enough to make iPad use viable, Ross says. “You could even control our plant from an iPhone,” he adds. “Because of the phone’s screen size, that isn’t realistic. But in an emergency I could shut the plant down with my phone.” Initial concerns about dust affecting iPad operation were allayed because the iPad has no vent holes or keyboards that could collect dust from the quarry. “No proprietary software is loaded on the iPad,” Ross says. “It’s basically a touchscreen remote for the main control computer that runs Windows.” Although Duff Quarry’s automated system can be connected to the Internet for updates and other resources, it’s only connected for short periods of time to address a specific need. “Our primary network is an intranet,” Ross says. “We avoid Internet connections as much as possible to reduce hacking potential. Programmers can access our system remotely to adjust it, but we’re very cautious with that.” Precise products Stedman’s Mega-Slam is a primary impact horizontal shaft impactor that effectively handles large feed sizes. The machine is built to handle thousands of materials, ores and chemicals in wet and dry applications. Mega-Slam’s design offers safe and easy access for breaker bar replacement and access to all other areas of the crushing chamber, according to the company. The machine’s front opening feature eliminates the need for a crane. The Grand-Slam secondary impact crusher, meanwhile, is built to handle the same type of materials as the Mega-Slam. Through design simplicity, employees have safe and easy access to breaker bars and all other crushing chamber areas. The twin impact crushers give Duff Quarry the cube-shaped rock that provides greater psi strength when used in concrete mixes, which represents a significant portion of their business. Integrated with an automated variable frequency system, the grizzly feeder provides the variable speeds that allow for maximum throughput without overloading the crushing plant. “Our plant has amperage and motion sensors on every conveyor,” Ross says. “Belt scales directly control throughput on the feeder so production runs at maximum speed without overloading belts. We also use tramp metal detection and pneumatically controlled discharge gates to dump material. In the event that metal makes its way into the plant, our automation system empties all belts to protect the crushers.” Quarry-wide benefits Photo courtesy of Duff Quarry The dolomitic limestone at Duff Quarry is desirable for construction materials like asphalt and concrete. With its automated system, Duff Quarry can also manage electricity meter spikes because the system will automatically cut feed rate if production exceeds 840 tons for more than five seconds. Each crushing plant conveyor is equipped with terminal strips wired to communicate production information to one main processor, allowing one staff member to monitor conveyor performance. All feeders and conveyor operations data are also recorded for use in evaluating the system’s overall performance. The new plant system allows Duff Quarry to crush rock in a variety of weather conditions, including heavy rain. Pumps and drain lines under the plant ensure that flooding cannot occur. The Duff family expected to reduce maintenance issues by at least 50 percent with the new plant because automated data management provides evidence of equipment issues well ahead of a breakdown. Since the plant can now be operated with just two staff members, the company no longer shuts production down for lunch hours. Adjusting product size takes just minutes, and the same conveyor can be used to handle different product sizes. Doubling output Overall, Duff Quarry more than doubled production capacity with its automated system and new plant. “We also have brilliant staff operating the plant,” Ross says. “Bill Page, a foreman here for more than 40 years, is a great example of that.” Over the years, Page tried different methods to prevent screen media clogging. He never found an effective product or method, so Page developed his own: the Blinding Buster. “We wanted to ensure our material quality on the finish end was automated, too,” Ross says. “Bill patented an invention to eliminate screen blinding. Every screen media, by nature, will blind, given the right conditions. The Blinding Buster continuously sweeps blinding off finish screens while we’re in production.” The Blinding Buster consists of two major components: the control assembly and motor assembly. The control assembly wires are designed to connect to the normally open auxiliary contact of a screen’s magnetic starter. The screen can be set up to start manually if the motor start isn’t available. The motor assembly includes a standard 20-ft., 3/8-in. chain that can be cut to any length or extended to accommodate all screen sizes. Installing the Blinding Buster takes a 2-in. black steel pipe mounted level approximately 6 in. above the screen opening. The pipe has to be affixed so it doesn’t vibrate with the screen. “The Blinding Buster allows us to screen in subpar conditions when we normally wouldn’t be able to,” Ross says. “We are also able to dry screen finish products without washing. We’re so happy with this product that we’ve made it available to other quarry producers.” Loretta Sorensen is a freelance writer in Yankton, South Dakota. She produces material on a variety of topics, serves as a ghostwriter and has authored her own books.

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.

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

Stedman “H” Series Cage Mill Efficiently crush, pulverize, blend and mix abrasive or non-abrasive wet, sticky or dry materials Stedman's "H" Series Cage Mill can crush, grind, pulverize, blend and mix abrasive or non-abrasive - even wet, sticky or dry materials - more efficiently than any competitive machine. They also provide a finer, more uniform grind. The "H" mill is engineered and built to operate at or near peak efficiency for a longer period of time, and continues to provide a greater return on your capital investment over its extended useful life. • Four standard "H" mill sizes provide capacities up to 240 tons-per-hour of crushed product. • Quick-opening feature for periodic inspection and maintenance. • Compact, unitized construction, occupies up to 45% less floor space. • Positively seals the housing. • Provide optimum utilization of crushing components.

The Stedman V-Slam™ is not only an excellent option for your coarse to fine crushing needs, but with a significant savings over high priced competitive units, the value is clear. The Stedman V-Slam™ minimizes operating costs with a low horsepower requirement per ton of throughput. Operating at one of the lowest wear costs per ton in the industry, the Stedman V-Slam™ is the solid choice.

Stedman Machine Company, Grand Slam Secondary impact Crusher • High crush count with cubical product• Low initial investment • Interchangeable wear parts • Exclusive rotor lock table for easy serviceability • Adjustable product control • Low operating cost

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For over 100 years, Telsmith, Inc. has been providing the global mining and aggregate industries with crushing and vibrating equipment, modular stations and portable plants through integrated solutions designed to improve efficiency, profitability and safety. A global network of dealers and factory representatives are available to provide the right solution for aggregate, mining, industrial, or recycling needs, as well as the parts and service to keep Telsmith products running for decades.