Staying Ahead of MRF Tech

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Today’s material recovering facility is a multimillion-dollar marvel of technology and automation. With its variety of screens, rollers, wheels, magnets, eddy-current separators, sorters, compactors, and balers, automation has replaced most of the human labor in all but one critical area: maintenance. And as capacity rates of 25 tons per hour become common, a breakdown can be nothing less than disastrous. Moreover, there’s the reputation of the equipment manufacturers, and as you’ll see, they stake their reputations on preventative maintenance, so they’re eager to share their strategies for keeping the plant humming.

A sound maintenance strategy is especially important to a facility planning to expand production or start an additional shift. And considering the steady growth of recycling in the US, it’s a likely scenario. For example, the Institute of Scrap Recycling Industries reported in May 2011 that the industry grew 40% in terms of monetary value, since 2009, and added 10,000 jobs from the first quarters of 2010 to 2011.

Bay Area Single-Stream
California has long been a strong market for industry growth, and preventative maintenance is critical for a new 45-ton-per-hour, dual-line recycling system at Shoreway Environmental Center, in San Carlos, CA. Designed, manufactured, and installed by Bulk Handling Systems (BHS), of Eugene, OR, the 70,200-square-foot facility is operated by South Bay Recycling and owned by South Bayside Waste Management Authority (SBWMA), representing 12 communities in San Mateo County. Company officials predict the new MRF will boost recycling in those communities by an additional 15% to 20%. According to Ed Hurlburt, parts and service manager at BHS’s newly expanded Priority Support Department, Shoreway represents one of the largest municipally owned recovery centers in North America.

The plant processes recyclables through a 25-ton-per-hour, single-line, residential, single-stream system, plus a 20-ton-per-hour commercial system that incorporates the latest in patented screening, air, and optical technologies to attain maximum recovery and purity. How pure? The recovery rate should exceed 95%, and, according to the SBWMA, the new facility is “a national model for sustainable building practices and innovative recycling and material handling operations.” There’s even an education center that includes tours of the processing system. The company expects a steady stream of visitors, from local schoolchildren to waste industry leaders worldwide.

As a showplace for the county’s recycling effort, it’s not surprising that the SBWMA expects nothing less than optimum performance, and that’s one of the reasons it contracted with BHS for a 10-year maintenance program. Says Hurlburt, “We’ll begin with a quarterly review of the system, and they will be with us and learning and making their adjustments, and keeping that system running at optimum efficiency for the duration of its operations.”

Training with hands-on demonstrations and working with a plant’s existing maintenance staff is important to a successful program, as are customized maintenance courses. “We travel to the site and spend one to three days in a combination classroom and plant environment,” says Hurlburt. “Our customers are very talented maintenance people but they need to understand the proper way to make adjustments and to analyze equipment to determine how it’s operating. These classes give us an opportunity to train the customers to be experts on their equipment.”

The need to handle a commercial wastestream presents some unique equipment demands that start before the waste enters any MRF operation, according to Scott Cloud, sales representative at Keith Manufacturing Co., of Madras, OR. A MRF operation expects to see scrap unloaded quickly when large truck-and-trailer rigs arrive with tons of commercial scrap, and the Keith Walking Floor system was designed for the self-unloading of nearly any bulk material in minutes. Keeping the floors in top shape is mostly preventive maintenance, but there’s also room for training operators in the concept of preventing abuse.

“It’s typical to see a loading operator throwing in items that are heavier than what the system is recommended for,” says Cloud. “For example, I have seen engine blocks literally dropped onto trailers from 15 feet up. You can do that a couple of times, and after that the floor starts breaking up, as does the trailer. That being said, Keith does design systems for nearly every application, so contacting the local sales rep is always a good way to go when dealing with an extreme application”

Beyond providing a quick course in the laws of gravity, Cloud notes that it’s good to stay on top of the hydraulic oil that flows through the power system. “We’ve done a good job in building a system that traps dirt and grime, but when you start getting pieces of metal, such as shavings or particles of material from the pump, that’s when you start seeing problems,” says Cloud.

The solution is fairly simple: Keep the oil clean and cool, and keep the filter up to date. Because trucks typically unload within five to seven minutes, and it is typical to see about five loads per day, the oil has time to cool down in the reservoir as long as the system is properly sized. “We recommend for trailers that if you’re pumping 30 gallons a minute to maintain your speed of unloading, then you should have a 30-gallon reservoir,” says Cloud.

So if a trailer or truck is on a quarterly inspection schedule, inspect the oil level and cleanliness, pressure settings, and pump operations. “If you notice above-average heat or longer unloading times, that would indicate some sort of a bypass in the system that’s losing a volume of oil, and most likely the pump is spinning more but generating less flow,” says Cloud. “We recommend that operators visually inspect the drive daily. If oil is dripping on the ground, that means trouble.

As for the slats that compose the Walking Floor systems, they are made of aluminum unless the customer transports a highly abrasive material. The discharge end of a slat tends to see a higher rate of wear, and Cloud notes that slat life can be extended significantly by rotating them, a process similar to that of rotating tires on a car to get even wear. The slats ride on plastic bearings. Rough movement, unusual noise and vibrations, or large deformations in the slats can indicate a broken bearing that needs replacement. Deformed slats should also be removed and straightened.

Keith offers a variety of service programs to suit a company’s maintenance requirement. Service technicians are available for contracts that include regularly scheduled inspections, repairs, and parts. “Here at Keith, we really try to focus on the end user of our product. Our regional sales reps go the extra mile to help out our customers and offer free service clinics to trailer manufacturers, service centers, and end users. We also have a technical department that will walk customers through troubleshooting.” Keith customers could be racking up many more tons on their systems in the future, since scrap metal recycling is on the rise, according to the IRSI. Seventy-four million metric tons just in the category of iron and steel for 2010, up from 70 million metric tones in 2009.

Maintenance and Safety
Growth in scrap paper recycling was almost as strong. Nearly 46.8 million metric tons for 2010, an increase from 45.4 million metric tons in 2009. But the growth in automated technology for sorting the metals, paper, plastic, and more is even more impressive. For example, look at the range of materials sorted by CP Manufacturing Inc., of National City, CA. The company’s technology handles curbside, commingled, fiber, MSW, commercial and industrial, waste-to-energy, and construction and demolition.

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Photo: CP Manufacturing
Because of its complexity in a harsh environment, MRF separation equipment needs careful attention.

Single-stream MRF continues to grow in tonnage, and to keep up with the growth, companies are offering broad lines of products. In the case of CP, that includes the company’s NEWScreens, as well as container/paper screens, V-screens, scalping screens, glass breaker screens, fines screens, and OCC disc screens, plus Multiwave, Sapphire, Aladdin, and glass optical sorters.

“This industry was very small in the beginning, but now it’s larger and much more complicated,” says Hans Ouellet, sales director with CP Manufacturing. “If people don’t do weekly and monthly maintenance, there will be trouble. In some areas it should be done daily or twice a shift, such as the wrapping shaft. The wrapping disc can get clogged, and it’s all part of the maintenance routine. We provide all the information as far as preventative maintenance, and the staff gets trained onsite when we do the commissioning. And that’s both verbal and live demonstrations. CP owns a recycling facility, so we know both sides of the operation.”

Such training is a valuable resource for MRF companies, and Ouellet says that they are very positive towards preventive maintenance and have a staff because they recognize the critical need. “If you’re dealing with good people, they can see or hear a vibration and shaft or bearing that’s defective, and you can hear the noise.”

Safety awareness is also part of the training. “You need to make sure the machinery has all the safety equipment that’s required by OSHA, like hand guards,” says Ouellet. Violation fines from OSHA can be costly. The agency recently fined a recycler in Florida $425,000 for allowing workers to operate machinery with a broken guard designed to keep workers from being exposed to amputation injuries. Additional violations included failure to train employees on machinery hazards and safety procedure, storing propane tanks in a dangerous area, allowing employees to handle corrosive chemicals without a proper eye-flushing station, and exposing employees to electrical hazards.

Among its preventive maintenance offerings, CP has technicians that can be scheduled at flexible monthly intervals to give advice onsite, conduct updated training sessions, order spare parts, and upgrade equipment. “A project is never finished,” notes Ouellet. “This equipment can last for 20 years and more because we’re doing continuous follow-up.”

The technology for sorting plastics has advanced rapidly, with CP and other manufacturers offering near-infrared sensor technology to analyze and classify polymers, aseptic packaging, and paper by their unique signatures. But according to Hurlburt, such technology items as the optical readers are typically the least understood technology for MRF maintenance staff. “They use light and sensors to detect infrared signature of materials and reject plastics based on that signature and HD color,” says Hurlburt. “So because there’s software and electrical technology involved, they are more misunderstood than screens and conveyors and other hardware that have been around for quite some time. We offer programs to provide additional service and support on those.”

Sorting Out Metals
Metal sorting is another area of sophisticated technology that continues to improve, and it’s driven by a rising demand for metals worldwide. In 2010, the United Nations Environment Program reported a substantial shift in metal stocks from belowground, to use in applications within society aboveground. As metals are inherently recyclable, the metals stocks in society can serve as huge mines aboveground. However, the UN found that the recycling rates of many metals are very low, and warned that the recycling rates of some rare metals used in such applications as mobile phones, battery packs for hybrid cars, and fuel cells are so low that unless recycling rates rise dramatically, these critical metals will be unavailable for use in modern technology.

Products such as those from Steinert US, located in Erlanger, KY, demonstrate the evolution and efficiency of the technology used to recover such metals. The company’s MTE Drum Magnets are designed to yield clean and consistent ferrous metal products as well as nonferrous raw materials. The XSS series sorters X-ray metal then separate nonferrous into heavy and light alloys. The NES eddy-current separator has a self-cleaning/adjustable rotor design for nonferrous metal recovery.

“The equipment is tough and durable, and it’s going to give you years of trouble-free service, but it must be maintained,” says Charles Winum, waste and mining market manager, Steinert US. “Nothing is bulletproof, and all of the items that are typical in conveying and material handling systems have the same rules. Bearings need to be greased, there’s no way around that, and we offer a preventive maintenance contract where our guys provide service on a predetermined schedule for things such as greasing bearings, aligning belts, and making sure that the electronic settings on equipment are set to the optimal operational potential.

Preventive maintenance agreements are far and away the best way to be sure that machines will operate and pay for themselves over and over, adds Winum, but there’s also a benefit in having the facility’s staff adopt a policy of equipment awareness. Says Winum, “When operators are around equipment it’s always good to listen for noises and get comfortable with the typical sounds in the machine so you can recognize something unusual. With something like vibration it’s certainly worth noting the normal vibration threshold on a platform so you can recognize a change and notice that maybe it’s time to check those bearings and see that they’ve been greased properly. If there are vibrations in a particular area such as the motor or pulleys, or a belt is not tracking properly, those are the types of indications that should be watched after establishing a baseline.”

On eddy-current machines the control panels have indicators that signal problems. So when operators start their shifts they can look at the fault indicators and see a history of the machine’s behavior. “Maybe the second shift restarted the unit and there’s a history of what occurred,” Winum explains. “So if there’s a pattern of problems like belt tracking being off, they would know that there is something more than normal that requires a service technician to investigate.”

It’s also wise to keep an eye on conveyor belts and the discharge hood of the eddy-current machine. For belts, abrasive materials such as glass can cause wear. And how that material is fed onto the conveyors is important. Rather than dropping from excessive heights, it’s best to minimize the drop or use a ramp that reduces the impact and extends belt life. On the eddy-current separator there is a discharge hood that adjusts with a splitter built into it in. At the recovery split point stray material such as paper can collect on its edge. “If you see a pattern and it builds up, you need to check it,” says Winum. “The whole point of the splitter is to create a barrier between the nonferrous and other material, and if it collects waste material you’re throwing nonferrous metals into the reject material, and you don’t want to do that.”

Steinert offers service contracts, and technicians are scheduled based on the MRF’s operation and type of application. “We do the installation, and follow-up service includes a full inspection of the machine and critical elements,” says Winum. One final word of advice from Winum is based on his observation of the customer’s desire to attain the maximum recovery and efficiency in metals. “If you want to make sure that you’re getting the biggest bang for your buck, the whole secret to material separation of metals is in the presentation of the material to the magnetic zone,” says Winum. “Spread the material out so that by the time it goes to the field you don’t have three or four layers of material stacked on top of each other. The way to do that is to use a vibratory feeder just in front of the eddy current. It will improve the performance dramatically.”

Feeding, Sorting, and Baling
General Kinematics Corp., in Crystal Lake, IL, is one of a number of companies that specializes in vibratory feeders, and also mechanical, optical,

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Photo: Bulk Handling Systems
A BHS Metering Bin (green) is seen at left; bunkers for final products are located at middle and right.

and manual sorting systems and equipment. “This feeder is a natural-frequency machine and very energy efficient,” says Dick Reeves, industry sales manager for General Kinematics. “With the springs we have, which are reactor and drive springs that connect from the shaft, it can take absorption and abuse. I tell our customers that these machines run quiet when you start them empty, so they should listen because a noise could mean a spring or rocker is loose.”

The other area of concern is the displacement on the drop-and-bouncer section. “Once a week or every day, the staff can mount a little plate on each unit, and a portable strobe meter can be used to get a digital reading off that plate,” Reeves explains. “Natural-frequency machines rely on displacement, and that’s recorded on the strobe or digital meter. If you get a buildup of material, you may have lost a spring but you can’t physically hear it. Yet you’d see a change in the readout from the strobe.” If the strobe shows a problem, start with physical inspection of the machine for any buildup of material, followed by a look at the spring mechanisms.”

When all the various material streams have been sorted, there’s still the final step of baling, and balers should get the same level of attention as any other equipment, says Gary Brooks, sales director, Nexgen Baling Systems, Vernon, AL. “With every Galaxy 2 Ram that we sell, we send a factory technician to the facility for three full days for startup and operator training,” notes Brooks. “That’s our way of ensuring that the maintenance practices take hold. It’s one thing to leave a manual with the machine, but operators often don’t take the time to read through these manuals like they should. As an added value service, we send a factory technician out, and they demonstrate the best practices and procedures and periodic maintenance schedules for all the tasks required. Most of it is based on hourly operations, because that’s how we gauge the usage on the machine.” Equipment manuals come with forms to check off maintenance items as required.

“We try to educate the customer on the critical nature of maintenance because maintenance and cleanliness of the machine definitely define its life span,” adds Brooks.

It starts with good housekeeping. Basic things should be done every day, such as keeping the unit clean, and material shouldn’t build up on the ramp. A visual inspection should look for leaks in hydraulic feeds and lines. Listening also plays a role.

“Once the operators are familiar with the machine, they know how the baler is supposed to sound,” says Brooks, “and a lot of times, if you have a hydraulic issue, it’ll make a distinctive noise, or sometimes there’s an unusual vibration that can be a red flag.”

Another area to watch is the shear gap. “It’s one of the most critical things that people ignore, yet the shear bar on the body and on the ram have a tight tolerance set at 15-thousandths of an inch. As a shear gap increases, you create undue stress on the shear nest and the ram/floor, because materials get torn rather than cut. As the gap increases, it causes premature wear on the ram bottom and the floor of the machine, because you’re creating downforce.”

Historically, Nexgen has seen that the shear gap adjustment has been neglected because it was difficult for the operator to get into the machine and unbolt the sheer bar from the body and correct the problem. “Nobody enjoys getting in there and doing that,” says Brooks. “But we designed an external adjustable shear bar with a row of bolts on top of the shear that’s accessible from the outside. It makes it so much easier and we see that people don’t neglect the settings anymore.”

There are no belts on Nexgen balers, but there are hydraulic power units that require periodic oil sampling. “A lot of these machines will have a 300- or 400-gallon hydraulic oil reservoir, and you don’t need to change it unless it’s breaking down,” says Brooks. “It has a filtration system, and the control panel warns if a filter change is required.” Additional lubrication points on the machines are outlined in the manual.” For factory service, Nexgen products have modems that allow technicians to diagnose equipment remotely. Onsite service is available when needed, and the company has an 800 number for the service department.

Pay Attention to the Specs
From the balers all the way back to the loading dock, it’s clear that today’s MRF is truly the sum of its many parts, yet the various components must all work together to send those bales on out to the shipping dock. And it’s worth asking the question: Is there an overall philosophy that should be considered when looking at an MRF’s operations?

Most certainly, according to Boudewijn Beukenkamp, field startup specialist at Van Dyk Baler & Lubo USA in Stamford, CT. “What I see in the industry is a desire to go faster than the recommended specifications,” says Beukenkamp. “So a customer buys a 25-ton-per-hour system, and we successfully prove to them that it runs at 25 or more. Then I come back for a visit and see that they’re running 35 tons an hour. Of course, they are pushing the envelope, and the problem is that the envelope gets bigger and bigger and they don’t realize that it’s beyond the breaking point. The quality goes down while the downtime goes up. Then they try to go faster and make up for lost time and completely forget that it’s not how it works.”

Van Dyk Baler is the exclusive North American distributor of Bollegraaf Recycling Machinery, consisting of balers, sorting systems, shredders, conveyors, screens, packing presses, roll cutters, and more. Beukenkamp notes that in terms of service, the company offers complete coverage and service technicians/engineers are trained on every part of the equipment, rather than employing different engineers for different aspects of the system. Technicians are located in four cities in the US, and Toronto, Canada. Free phone support is available six days per week.

One of the common threads in proper maintenance has been to keep these very expensive machines clean, and that includes controlling the dust that every facility must contend with. Wet mist suppression is an effective method for controlling and suppressing dust and smoke. By creating a wall of micron-size water droplets, airborne dust and smoke particles bond to it, then become heavier and drop to the ground. In the case of the Buffalo Turbine Monsoon, manufactured by Springfield, NY-based Buffalo Turbines, water filters out of a mesh screen, called a “Gyratory Atomizing Nozzle,” and is distributed into the air by a turbine-force wind. The turbine can be powered by gas, diesel, electric, hydraulic, or a vehicle’s power takeoff unit.

“Maintaining the product is basically keeping it clean, such as cleaning any debris from the blower wheel and atomizing nozzle,” says Brad Wesley, Monsoon sales and marketing, at Buffalo Turbine. “The problem is a dusty environment; therefore, you have to make sure to do the proper engine maintenance or electric motor maintenance. If somebody brings our turbine into their shop and never changes the oil, they can take it from a six- to 10-year life expectancy down to about two to three.” On the company’s newest diesel unit, the high-volume, heavy-duty air filter has a pop-up signal that indicates when a change is due, and an automatic shutoff engages if the filter is overcome with debris.

From simple automatic shutoff functions to remote diagnostics, the technology for MRF equipment continues to evolve. Already in place on BHS systems, SCADA (supervisory control and data acquisition) continues to become more sophisticated, making it possible for operators to fine-tune a system for maximum recovery. “We’ve been building SCADA into our systems,” says Hurlburt. “It provides data on operational effectiveness of the system and allows us to capture information on downtime, see the status of our equipment at remote locations, and then make changes and recommendations on how to run the hardware more efficiently.”

The aption of SCADA technology will have a significant impact on MRF operations, however, the need for awareness and understanding of daily operations and routine maintenance will remain. And when proper maintenance methods aren’t applied, the need for advice, service, and repairs, will also remain. Msw Bug Web

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