Popular proven solutions, adapted with comparably minimal capital expenditures and infrastructure or process upgrades, can help cut costs and improve production
By Jesse Morton, Technical Writer
Suppliers in the coal crushing and screening space say adoption of certain comparatively small solutions can bring big benefits to a plant. The benefits include reduced capital and maintenance costs, and improved plant performance. Most of these solutions are field proven and can be adopted with relatively minimal disruption or updates to existing infrastructure or processes.
McLanahan reported its sizers are a cost-effective crushing-circuit solution that can help an operation improve efficiency and productivity, and better field challenges posed by supply chain and labor market constraints.
Smaller than a crusher, McLanahan DDC-Sizers “incorporate two rolls with teeth that rotate either toward or away from each other at lower speeds in order to minimize fines generation and overall plant operating costs,” the company said. “McLanahan offers many different roll designs, tooth configurations and material selections that are engineered to maximize a sizer’s efficiency and wear life and to minimize the cost of ownership.”
Cost-effective, compact, and configurable, sizers add to the efficiency of a circuit. “McLanahan DDC-Sizers offer producers the ability to adjust roll settings in order to compensate for wear or to change product size requirements,” McLanahan said “Inward rotating sizers, primary, secondary and tertiary, feature hydraulic product size adjustment, while the outward rotating tertiary sizers are equipped with adjustable sizing combs.”
Sizers cut costs by reducing the wear on and workload of downstream machines. A sizer effectively serves as “a rotating screen, allowing undersized material to simply pass through and only breaking the material required to be crushed,” said Lee Hillyer, director of sales, mineral systems. That prevents further inter-particle crushing, reducing operating costs for downstream equipment, the company said. “DDC-Sizers run with low roll speeds to ensure minimum fines and dust generation.”
Sizers save on installation costs. With a direct drive arrangement, a sizer entails minimal capital installation costs compared to a small crusher.
With high-capacity throughput, DDC-Sizers can help a plant increase productivity. A sizer “can achieve very high productivity with a very small installation footprint,” Hillyer said. A sizer can achieve the throughput of a crusher four times its size.
The DDC-Sizer also adds value by efficiently processing problematic material. “It is designed to handle clay and other materials, which are often big factors in plant downtime,” he said. “The sizer simply crushes material and shreds the clay in one single process, preventing unnecessary downtime spent washing out the machine.”
That capability gives the DDC-Sizer a “very high availability, especially when processing wet sticky clay material, when other crushers would tend to bog, which can often cause extensive downtime,” Hillyer said.
With a small footprint and high efficiency, a sizer can help a miner meet sustainability goals and regulations. “Sizers are smaller, more compact, weigh less, and have a much smaller crushing station than that of other crushers,” Hillyer said. Because of the compact design, adoption and installation requires less earthwork and construction. That “offers a much more positive effect on the environment and future rehabilitation.”
DDC-Sizers draw comparably less power. “They run on a lower absorbed power than other crushers, consuming less electricity for the customer,” he said.
The sizers are designed for ease of maintenance, which can help a miner attain some safety goals. “DDC-Sizers have a fully enclosed direct-drive configuration with a low-profile design that can be mounted on rails and rolled out from under a hopper or feed chute for easier, safer access during maintenance or to remove uncrushable tramp material,” Hillyer said. “This allows operators complete access without having to crawl into feed chutes, work in confined spaces or having to work at elevated heights.”
Parts commonality and the modular design of the sizers means wear components “are fully interchangeable throughout the machine,” McLanahan said. “Parts and assemblies that do not require routine maintenance have been designed so that they can be replaced in the least amount of time using standard tools without the need to disassemble the entire machine,” the supplier said. “We also offer off-the-shelf gearboxes that are directly available from the gearbox manufacturer.”
Backed by the McLanahan service network and organization, the DDC-Sizers can help a miner better contend with both labor market and supply chain constraints. “As a global business we have engineering and supply chain resources around the world,” Hillyer said. “This allows us as a business to lean on different areas of the organization and supply chain to meet the demands of our customers in a labor-constrained market,” he said. “Using our global network allows us to share the workload within the company to de-risk ourselves and our customers when particular areas of the world could be more constrained from labor resources than others.”
With a standard range of products and parts, McLanahan offers the capability to “quickly execute projects, commence engineering earlier, and reduce lead times to our customers,” Hillyer said. “Therefore, with our strong portfolio of key suppliers coupled with our standard range of products, we are well placed to cope with minimal supply chain constraints and disruptions, ensuring our customers get their products on time and on budget.”
Pin-less Polyurethane Panels
Elgin Separation Solutions said the Tabor-Thane polyurethane screens do extremely well in a dewatering machine where the transition area leaves a section of exposed metal. “The system allows this area to be protected, and therefore reduces wear on the deck frame,” said Tim Lilly, vice president, business development.
The screens can be used on almost all OEM vibrating screens for sizing, rinsing and dewatering. “The Tabor-Thane system provides precise separation of material and we have a wide variety of sizes available,” he said.
Typically sold as 12- x 12-in. panels, the screens can be as thick as 2 in., and with apertures as small as 0.25 mm or as large as 3 in. “Our modular system has the capability to mix and match types of screen media without having to modify the customers screen deck or machine,” Lilly said. “The customer can use urethane panels, profile wire panels, woven wire panels or perforated panels in the same deck at the same time if they desire,” he said. “This gives the customer options for their screening needs.”
The screens are pin-less, a feature that offers several benefits. “The pin-less system allows for easier and faster replacement of panels,” Lilly said. Without pins or plugs, panel change-out is simplified and expedited.
“Easier and faster replacement equals less downtime for the machine,” he said. “Only one person is needed for replacing panels, so it would be less labor changing the modular system compared to conventional 2- x 4-ft panels or hooked screens.”
Another benefit offered is longevity. “By using urethane, the life of the panel is extended,” Lilly said.
Elgin stocks many sizes. This helps “to reduce lead time and to eliminate supply chain issues,” he said.
The screens are for use on a deck system with 2-in. square tubing and 15/16-in. holes on 4-in. centers. “This is a typical deck for a Tabor vibrating machine,” Lilly said. “However, competitor deck frames can most likely be converted to this system with no issues.”
The screens first launched in the 1980s with the original Tabor-Thane system and with the pin-and-leg design. “The pin-less system was patented November 18, 2014,” he said. Since then, feedback from customers proves the screens to be “a better product that helps customers be more efficient in their operations with better screening capabilities and reduced maintenance costs.”
Separately, Elgin Separation Solutions said it will release the HVC-750-101 in Q2.
Development of the new centrifuge launched when a customer adopted a larger HVC model that proved to be too big for the space allotted, the company said.
“Last year we allowed a customer to test the HVC-1000 for their application and they were very pleased with the performance and test results,” said Cory Fulkerson, engineering manager. “Unfortunately, due to existing constraints, the HVC-1000 footprint was too large to replace the equipment they are targeting.”
The unit’s production exceeded the requirements. “Therefore, after discussion with the customer, we decided to scale down our HVC even more, and developed the HVC-750-101,” he said.
The first unit is being assembled and will be delivered in late April.
“This machine is intended for smaller feed rates with operations that have limited space and want lower capital and maintenance costs,” Fulkerson said. “The HVC lineup is the smoothest operating centrifuge available on the market,” he said. “Replacing existing equipment with an HVC machine will reduce stress on the supporting structure and reduce the plant’s maintenance cost.”
The horizontal vibratory centrifuge is used to separate liquid and solid mixtures for further processing, recycling, or to decrease transportation weight. “Compared to our HVC-1400, 1500, or 1700 machines, the HVC-750 offers the same technology in a smaller footprint, which lends itself to be better suited for low-throughput applications,” Fulkerson said.
HVC machines can be configured based on feed material characteristics, performance needs and maintenance goals. “The variability of the HVC allows an engineer or operator to hone in on a rotational speed and vibration level setting that establishes peak liquid-solid separation without causing excessive wear or strain on the machine,” he said.
“With simple sheave changes, the rotational speed of the screen can be increased or decreased to adjust the G-force levels exerted on the material,” Fulkerson said. “Likewise, weights on the vibration system can be adjusted to increase or decrease material retention time on the screen.”
The centrifuges feature drive unit bearings that operate in an oil bath, nixing the need for a separate oil system that could include pumps, filters, and pressurized lines. “By eliminating an external oiling system, we have eliminated a separate system that requires regular maintenance that could fail and cause downtime and prove costly for repair,” he said.
On HVC machines, “all maintenance is performed above the floor, eliminating the need to lock out belt lines below the machine or for access to confined spaces below the floor,” Fulkerson said. “Simply open the front door in order to inspect and replace wear components as necessary.”
The centrifuges are designed to limit the amount of energy that is transferred to surrounding equipment. “The vibration system is isolated via composite springs,” he said. “Therefore, our equipment operates smoother and doesn’t violently shake structural components and nearby equipment to the point of failure.”
Elgin Separations Solutions equipment is manufactured and assembled in the U.S.A. “Many of the components are manufactured in house or at local suppliers, putting us in direct control of product quality and lead times,” Fulkerson said.
Adoption of the new HVC-750-101 could require “modifications to existing structure and chute work,” he said.
“To facilitate equipment change outs and to minimize any major structural modifications, Elgin can design adapter plates for most installations, should the customer desire,” Fulkerson said. “The HVC will require the necessary power supply to the drive motor and two vibration motors, which vary in horsepower depending on the size of the machine.”
Spray-on Protective Coating
Polydeck Screen Corp. reported PROTEX UC is quickly becoming the standard for equipment preservation in highly abrasive and corrosive applications. “We are seeing increased demand and inquiries for this from our coal and mining customers,” said Aaron Boggess, sales director.
The spray-on sealant is the culmination of recent advances in urethane coating technology, and offers “a more durable, weather-resistant, and UV-resistant protective covering for equipment, frames, and stringers,” said Trey Rollins, marketing director.
Beyond sealing the equipment, “rust formation under or around the edges of the coating is further controlled chemically by the addition of a rust inhibitor with the surface primer,” the company said.
“Through testing, PROTEX UC has demonstrated superior durability and resistance to weathering, chemical and water exposure, and wear and tear, and offers a wider range of flexibility and customization than other protective coverings such as rubber lining,” Boggess said. “It is considered a flexible and reliable solution that can be applied to a variety of surfaces and can be customized to suit the specific needs of the application.”
Compared to a rubber-based sealant, PROTEX UC is easier to use. “PROTEX UC is applied using a proprietary method that allows for a quick and even application,” Rollins said.
“Rubber lining, on the other hand, is typically applied by hand and does not fully-encapsulate a frame,” he said. “Rubber lining is also not able to be applied to stringers, which are exposed to abrasive conditions, which cause them to wear out more quickly.”
Compared to a rubber-based solution, PROTEX UC is more durable. “Rubber linings are also durable but may not have the same level of resistance to impact, abrasion, and chemical exposure,” Boggess said. It is also “more flexible than rubber lining and can adapt better to the movement of the metal frame structure, which can help to prevent cracking and damage to the coating.”
Benefits can include significant cost savings. “Equipment, frames, and stringers last longer,” Rollins said.
“A mine manager or company executive would want to adopt the use of PROTEX UC because it can increase the life of their equipment, saving on maintenance and replacement costs,” he said. “Support frames coated with PROTEX UC have proven to last up to 33% longer than uncoated frames, and up to 50% longer than uncoated frames in certain applications.”
That additional longevity can help customers challenged by labor market and supply chain constraints, Boggess said. “With skilled labor being in short supply, Polydeck is always looking for ways to add value to products for the industries that we serve.”
The sealant can also contribute to safety improvements. “It reduces noise level 5 to 7 points per mm of thickness,” Rollins said. “The thickness of PROTEX UC can be adjusted based on how extreme the application is,” he said. “The most common use is 1/8 in., but in some cases 1/4 in. is used.”
Polydeck recommends PROTEX UC for new frames and stringers deployed to wet applications or in corrosive environments. “It is most effective in abrasion protection when used in slurries containing particles smaller than 1 in.,” the company said.
The solution is one example of the results of the company’s efforts at continuous improvement of its offerings, Boggess said. “Polydeck invests heavily in R&D to develop innovative technologies that we can incorporate into current and new products,” he said. “We are committed to designing products that solve problems and provide the best solutions to our customers.”