Maintenance in Uptime Pays Off in Downtime

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Ensuring that the 50,000-square-foot Tri-County Single-Stream Recycling facility in Appleton, WI—one of the largest publicly owned material recovery facilities (MRFs) in the country—stays operational is of utmost importance. The facility serves more than 60 communities and at least 200,000 households throughout Outagamie, Winnebago, and Brown counties in northeastern Wisconsin by processing more than 50,000 tons of containers, plastics, metals, old corrugated cardboard (OCC), newsprint, small-paper fiber, and glass per year. The facility was recognized with a SWANA Gold Recycling Systems award in 2010.

“Full shutdowns for maintenance—that’s a big issue,” says Phil Stecker, director of solid waste for Outagamie County. “We can’t afford many full shutdowns; that affects our daily and weekly production.”

Like his MSW manager peers across the nation, Stecker is fully aware of the deep, severe recession. Like many others, he realizes that major capital investment in equipment will probably remain low for a while. Publicly held companies face lower tax revenues, while privately held firms are confronting lower volumes of some refuse that one would expect to result from tepid consumer confidence. Many MSW managers in both groups are putting off major equipment purchases for as long as possible. So keeping existing equipment operating reliably has taken on greater importance than ever.

“We are facing the same challenges that everyone else is,” Stecker says. “We see ourselves in a growth mode. We have a new facility here, and we’re finding strong interest from other customers around the state to send us materials, so we envision that our annual tonnages and annual revenues will grow in future years. As we face those questions about expenditures, we certainly have to make sure that whatever we’re thinking about is a necessary project, but we also try to do the smart thing for the long term.”

Stecker and the county have plenty of equipment to look after. The machinery in the MRF includes a BHS metering bin, a BHS/NRT MultiSort optical sorter for polyethylene terephthalate (PET) plastics, a Dings Co. electromagnet and BHS eddy-current separator for metals, a BHS OCC Separator, BHS NewSorter No. 1 and No. 2 disc screens for newsprint, a BHS polishing screen, a BHS glass cleanup system, Keith Walking Floors for OCC and newsprint collection areas, a BHS dust-control system, and an IPS two-ram, 200-horsepower baler for multiple commodities.

Some equipment has been customized for the MRF. Stecker reports that several small modifications have been made to some of the equipment to improve production and reduce downtime. Belt scrapers were added in some locations to improve throughput and reduce wear. Access panels were added to the pneumatic conveyors to lessen the time needed to unplug them. To allow more frequent cleaning, an access point was added to the magnet and eddy-current separator, which pulls small pieces of paper out of an airstream that is incorporated into the glass-processing system. The access point is a hole cut into heavy steel plating that was sealed with a makeshift door. The equipment has been adjusted from time to time since startup to provide more efficient throughput. For example, the rotation speeds of the disc shafts are adjusted and the incline angle of the disc screen is adjusted in half-degree increments, according to Stecker. He adds that the speed of the tipping floor infeed belt has a large effect on how well the disc screens perform and may require adjustments throughout the day as material changes.

The county maintains a preventive maintenance schedule on the facility’s equipment. Belts are inspected and tracked, and disc screens and shafts are cleaned daily. Drive-chain wear and disc wear are checked for, and equipment is greased, once a month. Four times a year, equipment mounting bolts are checked for proper torque and gear-reducer fluid levels are checked. All routine maintenance items are tracked through Mainsaver software. The staff programs the frequency of preventive maintenance, and the program issues a work order for the maintenance staff.

Stecker points out that all preventive maintenance is based on recommendations by the manufacturer of the equipment, Bulk Handling Systems, which provided the staff with a thick operating manual, complete with maintenance schedules. Additionally, the manufacturer visits the facility four times a year to audit maintenance, provide advice on how to improve machine uptime, check settings, and inspect wear points. “It’s very helpful because they have a lot of experience with their equipment—they know what to look for as far as wear points that need special attention,” says Stecker. “Also, if we should ever have any new personnel in the plant who are learning the maintenance techniques, the visits provide an opportunity for the new person to meet with them and learn from them. They also provide training for our people when they come to visit. This is important to us as a county operation,” says Stecker, noting that a single facility serves three counties and downtime must be avoided at all cost.

The staff treats each piece of equipment with a customized maintenance approach. The metering bin is cleaned daily; the bearings are greased, drum alignment is verified, and mounting bolts are torqued monthly; and gear reducer oil level is checked and oil is replaced annually. On the optical sorter, the light bar and receivers are cleaned daily, bearings are greased monthly, and air valves are tested daily. Belts are inspected daily, bearings are greased monthly, and reducer oil levels are checked and oil is replaced annually in the electromagnet and eddy-current separator. Discs and shafts are cleaned and inspected on the OCC separator daily. Stecker reports that the discs are changed monthly, on a rotating basis. Drive chains are inspected for backlash and bearings are greased monthly and reducer oil is checked and oil is replaced annually. The same schedule holds for the disc screens and polishing screen.

The Glass Cleanup System is a very high-wear piece of equipment, notes Stecker, so the vibratory screen is cleaned and belts and drop plates inspected daily. It is subject to the same monthly bearing lubrication and reducer oil level check and oil replacement schedule as the other equipment. “Any place in the plant that experiences the presence of glass tends to be more problematic,” he points out. “This system receives a lot of attention for two reasons: One is that it receives very abrasive material, and the other is that it receives a lot of small-paper fiber, which, for the most part, is confidential shredded material. We have had some challenges with just the presence of a larger amount of this shredded paper than normal, and that causes difficulties in separating it from the glass. The system, which has an aspirator that pulls the paper off and makes it fall to the bottom, requires a relatively high level of maintenance to stay running.”

The Keith Walking Floors periodically require debris to be cleaned from underneath, slats to be checked for wear, photo eyes to be cleaned and inspected, hydraulic fittings to be checked for tightness, and oil samples to be taken. Stecker says that hydraulic hoses must be checked for leaks and repaired, and oil samples might indicate a pending problem or excessive part wear. The air compressor is periodically cleaned and inspected, the rotary actuator is inspected for proper function and the gauge checked to ensure the proper pressure drop across the filter system on the dust-control system. On the baler, the staff cleans behind the cylinders daily, inspects the cutting edge four times a year, cleans the cooling system, and changes the oil and air filters three times a year.

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Stecker reports that the county manages to have 75% of routine maintenance taken care of by the in-house maintenance employee, while the other 25% requires additional help either from other county employees or from a maintenance service. “We have found that it’s more cost effective generally to use in-house staff if we can, but there are some things that are very specialized, so we hire out of house for those,” he says. “An example is hiring an electrical contractor to clean our electrical panels, and we have Ingersoll-Rand come in to maintain our air compressors on a quarterly basis. Another thing we’re planning to do is have a contractor do a general cleaning of the plant.”

Plans exist to keep the plant running in the event of a major equipment problem. Examples include the aluminum and PET pneumatic conveyor plugging up with items that the sorters on the container line occasionally miss. Cut belts are sometimes caused by items that get by presort. If a belt is not torn too severely, the staff might use belt lacing or cleats to hold the belt together until shutdown. Another occasional problem is the vibrating glass shaker plugging up due to the presence of excessive shredded paper in the stream.

Problems that can lead to a full facility shutdown include motor failure, belt failure, and gear-reducer failure. Depending on the severity of the breakdown, the equipment is repaired by in-house staff or an outside maintenance service. “Typically, there is enough room on our tipping floor to accommodate a lengthy downtime period,” Stecker says. “If the floor is completely empty at shutdown, we could be down for a little more than three days and continue to take incoming material. But usually, we can hold our lengthy downtime to under eight hours.”

A wide variety of replacement parts is kept in stock at the facility: belts, motors, bearings, discs, shafts, drive chains, hydraulic valves and cylinders, transition plates, variable frequency drives (VFDs), and specialty parts for the optical sorter.“Many of them are wear items, but we also have what we call strategic parts,” says Stecker. “If we have a breakdown and we don’t have a replacement part, the plant might be shut down for a while, so we try to stock as many of those as possible. One example is our baler—there’s a main hydraulic manifold, and we had trouble at one point with that clogging and malfunctioning. So we are now stocking spare parts for that. We could replace that within a couple of hours and get back up and running.” Management also realizes that the reliability of the facility’s automation had to be addressed, so efforts are made to keep in stock at least one replacement unit of each Rockwell Automation programmable logic controller and VFD. Just as important, Stecker adds, the warranties on these units become effective when they are placed in operation, not at the date of purchase. Under this arrangement, the facility also automatically receives replacement units when the technology is upgraded.

Strict C&D Equipment Maintenance
Call the operations staff at MBL Recycling Inc., Palatine, IL, fanatics about equipment maintenance, and they would probably thank you for the compliment. The company, a major Chicago-area construction-and-demolition (C&D) debris recycler that spun off of Lenzini Excavating in 2005, constantly monitors its processing equipment.

Such vigilance is crucial: Despite the depressed national residential construction sector, the C&D recycler has kept its 52,000-square-foot facility processing 98,000 tons annually during the past couple of years. “Roofing has become huge this year—just this year,” observes office manager Wendy Gold, who owns the company along with her siblings Robert, Gina, and Lisa Lenzini. “The interesting part of this, so we’re told, is that with a lot of hail damage in the area over the past couple of years, the insurance companies are paying out claims. That’s been a real plus for us, the tear-offs of old shingles. Almost two years ago, we made an 11,000-square-foot addition to our building just to house shingle processing.”

Prior to the unexpected uptick in residential C&D volume, the company rolled along largely due to diversification. “We were very fortunate in the past couple of years, when things hit the skids, that we were focused on a lot of commercial and not so much in residential,” Gold says. “Now we are seeing a little bit of a slowdown on the commercial side. Luckily, we have a couple of very big homebuilders, like Cambridge Homes, that we do business with—they are still booming.”

Still, like many solid-waste processing companies, “We have not purchased any new equipment in the past year, due to the economic environment, and we do not anticipate any capital investments in the near future,” Gold says. “We have always focused on routine maintenance. The upkeep of our existing equipment is very important to us, and it always has been.”

Robert Lenzini and Dan Schmidt, operations manager, seem to eat, sleep, and breathe routine maintenance.

“Early in the morning when I get there, or late in the afternoon after everybody has shut down and gone home, I just walk through the plant—it might take me 10 minutes or half an hour—and I just look at things,” says Schmidt. “I know if something is wrong or out of place, or if I’m walking through the plant, while the equipment is running, I’ll hear a noise that’s out of place—those are the kinds of things I look for.” Schmidt reports that, beyond this attention to detail before and after startup, the company has a defined preventive maintenance schedule.

Heavy maintenance means lubricating the entire operation once a quarter. At this interval, the staff oils the drive chains on an apron conveyor, which a front-end loader keeps charged with C&D debris from the tipping floor. Schmidt adds that gearbox oil was also changed on this unit twice within the first three years per the manufacturer’s recommendations—the first time following a break-in period of several months. The company does not have problems with equipment failures due to overheating, according to Schmidt. “Most of the plant doesn’t have a problem with heat buildup, because when they built the plant they used the right equipment, the right bearings, they didn’t undersize anything,” he says of Sherbrooke OEM Ltd. and General Kinematics. “So we don’t have a tendency to have heat buildup to where we’d have breakdowns.”

The apron conveyor feeds a vibrating “finger screen” that uses multiple sizes of separating decks to segregate materials at 6 inches and 6-inch minus. The finger screen carries the 6-inch material to an “A” line above, and the 6-inch-minus material falls between the decks to a “B” line below. Schmidt reports that during its four-and-a-half years of life, the finger screen has required replacement of a bearing on the main shaft due to a bearing failure—roughly in line with its five-year life. On the B line, an overhead magnet-conveyor removes such materials as nails and rebar. A bearing failure occurred on the magnet, and the belt and bearing were replaced since the facility opened. Schmidt says that some metal pieces apparently had gotten caught in the belt, which had a small rip, largely contributing to the bearing failure.

Vibrating screens further segregate materials on the A and B lines. On the A line, workers assigned to specific types of nonmetallic materials—e.g., wood, cardboard, plastic, and roofing shingles—pick them off of the belt and place them into hoppers. Since the facility opened, the only component that the company has replaced on a vibratory screen for the A line has been “marshmallow springs” used for support. These are replaced about every year and a half, Schmidt says.

The facility also has a Dual-Knife De-Stoner that combines vibratory action and high-velocity, low-pressure air streams work to separate such heavy materials as concrete chunks and bricks from light materials such as paper. The “air knife” pulls the light materials upward, separating them from the heavy materials and depositing them onto the floor. The heavy materials fall off the end of the conveyor and onto a chute that diverts them into a bin. “That has been one of our no-maintenance pieces of equipment,” Schmidt says of the Dual-Knife De-Stoner. “Other than regular maintenance on bearings and stuff like that, we have never really had any problems.” So far, the only components that the company has replaced are rubber expansion boots on the air knife.

Schmidt says that the company’s preventive maintenance schedule was developed from experience and from manufacturers’ recommendations. In addition to quarterly heavy maintenance, monthly light maintenance of all equipment involves visual checks and such tasks as spraying chains with oil. For the most part, the staff diagnoses potential problems by sight, sounds, and touch, although Schmidt can think of one more sophisticated method. “Sometimes we take amperage draw on the electric motors,” he says. “That tells us if the motor is starting to go bad or if something is creating a heavier draw in the motor. If we see a spike in the amperage, we know there’s something to look for.”

Gold reports that about 90% of equipment breakdowns are related to belts. “We have never been shut down for more than a half a day at a time, due to belts or electrical failures,” Gold says. “The equipment has a control panel that includes four components for each piece of equipment, and a main computer board. Fuses need to be replaced at times, and motor starters need to be reprogrammed. Any other major repairs are performed after the plant is shut down for the day or weekend.” For repairs, the company has a 10,000-square-foot shop for tools and supplies. Belts are stored there, as well as lacing to tie belts together and repair tears or holes in them.

Insourcing and Outsourcing Maintenance
Adam Weitsman, president of Upstate Shredding LLC, Owego, NY, relies on two major concepts to keep his steel-recycling facility in operation: Keep a full inventory of spare parts on hand so that the in-house maintenance staff can perform routine repairs, and call in factory-trained technicians to perform major maintenance when needed.

Every year, Upstate Shredding processes about 750,000 tons of ferrous metals and 100 million pounds of nonferrous metal, with vehicles accounting for roughly half of the incoming refuse and light iron making up the remainder. The company, the largest privately owned scrap metal processor on the East Coast, recently acquired Weinstein Scrap Metal in Jamestown, NY, and is also planning to open a scrap metal facility in Scranton, PA. Upstate has invested $25 million in new high-tech equipment, consistent with Weitsman’s philosophy of expanding during a downturn, when capital is less expensive. The equipment includes a massive 10,000-horsepower Riverside Engineering 122-inch Mega Shredder that can shred entire vehicles and engine blocks at 450 tons per hour, a polishing drum magnet system that removes electric motors containing copper armatures from vehicles, four dynamic ferrous-metal separation systems that segregate nonferrous metals from ferrous metals, and optical color sorters that separate yellow metals from red metals. In addition, the company built a proprietary $8 million wire-recovery system that uses inductive metal detection and near-infrared scanning to recover and process copper wire encased in plastic insulation.

“Copper wire is something that we’ve landfilled since inception,” said Weitsman. “Seeing the trucks pulling out and paying to get rid of it—that’s a tough pill to swallow. This new system should generate $20 million of extra income a year.”

For Weitsman, maximizing return on assets is not just about a relatively inexpensive purchase price. He fully recognizes that steel processing is a maintenance-intensive business. “Every process in the shredding business is extremely high-maintenance,” he observes. “I’d say you’re doing 15 minutes of maintenance for every hour that you run equipment.”

Equipment downtime has a huge impact on the bottom line, Weitsman adds. “Downtime is the biggest expense in our whole company, next to payroll and equipment,” he says. “Most of the time, we sub out a lot of our maintenance, even though service contracts are pretty expensive. We just feel that it’s so much cheaper than to do it ourselves.” Factory-trained technicians periodically visit the facility and provide the in-house maintenance staff with tips on keeping equipment clean and properly lubricated.

“The biggest part of downtime is not having the spare parts on hand, so we make sure that we have a spare part of everything—small motors, gears, pulleys,” Weitsman points out. “It’s expensive, but in the long term it’s good to do it. If the factory doesn’t have the part, or if the delivery service screws up, you’ll have everybody sitting around. All of this equipment works in sync, so if you have something that breaks down, it really hurts the rest of your plant. “There’s always going to be downtime—we just try to minimize it.” MSW

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