BioCycle October 2007, Vol. 48, No. 10, p. 25
Preventive maintenance programs are critical for successful composting operations to avoid lost revenues while maximizing performance.
WEIGHING, grinding, mixing, turning, screening, blending and shipping. These are the normal operations performed every day, all day by moving machinery at compost facility operations. Those who sell bagged products have fillers, sealers and palletizers to operate as well. The reliable performance of all this equipment is critically important to either profitable private or under-budget public facility success.
The variety of elements in all this equipment that needs regular maintenance can be daunting. Mobile equipment includes transport-related items like tires, batteries, engine lubricants and, all too frequently, parts replacement. Materials handling equipment has, in addition to engines and tires or tracks, teeth, flails, chains, bearings, hydraulic lines and function-unique items like trommel screen panels and windrow turner drums. Due to the abrasive and corrosive nature of compost production, worn parts replacement is a frequent operating expense.
Maintaining equipment regularly should be a top priority in any composting operation. Not only is it less expensive to maintain equipment than to repair it, if a critical piece (like a windrow turner) breaks down, it can cause process control difficulties like anoxic (low oxygen) conditions in windrows, which, when eventually turned, may release odors that become a public nuisance. Preventive maintenance programs (PM for short) will not eliminate all potential for unexpected breakdowns, but they will greatly reduce how often breakdowns occur.
PREVENTIVE MAINTENANCE CHECKLIST
A good PM program should include: a list of required maintenance and when it should occur for each piece of equipment (developed from the manufacturer’s maintenance guide); a way to track equipment operating hours so you know when to service each machine; a method of performing the service (i.e. do-it-yourself, bring in a service contractor or take it in to a repair facility); and a complete service and repair history of each machine (essential if you ever sell the machine). A good PM program is more than just tracking and recording all that information. It is a mindset among good operators, who are always on the lookout for problems before they become problems. PM starts with careful and thorough observations of each piece of moving equipment before that equipment is started up in the mornings. Figure 1 lists steps every equipment operator should do before start-up, after start-up and after shut down. This checklist should be tailored to the types of equipment in use at the facility.
A checklist like this is used daily by the equipment operators at Novozymes, N.A. (an enzymes manufacturer outside of Raleigh, North Carolina with an on-site residuals composting facility), according to Frank Franciosi, the composting department manager. “The completed checklists get turned in to the office at the end of the day,” says Franciosi. “My office staff compiles the data using Excel spreadsheets, which I review weekly.” He notes that PM has definitely reduced the amount of time lost to unanticipated breakdowns and that it is a component of Novozyme’s ISO 14001 Environmental Management System.
A wood waste grinder is a very high-maintenance piece of equipment. The following recommended checklist for grinders (see “Summertime Tips for Grinder Maintenance” in the June 2001 issue of BioCycle, available at www.biocycle.net) could be applied to all composting equipment: 1) Wash the machine with a high-pressure power washer (protect electrical equipment by wrapping in a plastic bag) to clean out potential fire hazard materials. This also helps to identify any oil leaks; 2) Check for oil leaks (both engine and hydraulic) by moving the machine onto a concrete pad (like the maintenance shop floor) – this allows you to see leakage you might not see when the machine is sitting out in the field; 3) Conveyor belts are driven by drive pulleys and guided by idler pulleys, both of which should be free of debris and aligned so the belt tracks straight. A misaligned belt will quickly wear out the belt and strain the belt splice, guaranteeing several hours of downtime while the belt is repaired; 4) Make sure the fire extinguisher is in good working order.
Fire prevention is an important part of preventive maintenance. Gro-Bark, Ltd. (Ontario, Canada) is a compost producer who, in concert with their insurance company, wrote fire prevention guidelines for its grinding operations that are incorporated into the employee training program. Daily grinder maintenance at Gro-Bark includes removing debris and accumulated oil, grease and other flammables, and pressure washing the machine. There are also post-shut down maintenance procedures to be followed to minimize fire potential, such as checking for smoldering debris, standing the rear discharge conveyor vertical to remove dust and debris, and checking all bearings for excessive temperatures. Fire prevention guidelines spell out a post shut down inspection for fire hazards. They include moving a grinder away from the area of operation into a clear area at least 50 feet from other equipment. A truck is kept on the site at all times to move the grinder as needed.
WARRANTIES AND SERVICE PLANS
All equipment used in composting comes with a warranty by the manufacturer against defects, which covers parts and labor costs in the event of breakdown of a warrantied item. The coverage and length of these warranties varies with the type of equipment and manufacturer, but most offer buyers the option to purchase longer, more extensive warranties. “The standard Backhus (German windrow turners) warranty is one year or 500 hours, with the exception of wear items, glass and rubber,” said Lyndell Pate of N40 LLC, Inc., the North American representative for Backhus. “That is the standard warranty, but if anything on the turner fails and that failure is due to poor workmanship or faulty parts, it is replaced with no questions asked.”
Similarly, there are several different service plans available from most manufacturers, at different cost structures depending on length and extent of coverage. Pate noted that Backhus offers several different service plans to its customers. “Under these plans, we send factory-trained technicians to customer sites to perform maintenance activities as prescribed by the manufacturer. Our plan levels include labor only, parts only, and both labor and parts. We bill for services only after the work is done so there are no annual charges for services not received,” he explains. Franciosi at Novozymes (which has a Backhus turner) notes, “We have Backhus take care of all the maintenance on our turner because I feel it increases its value, should we decide to sell it someday. And as I don’t have a dedicated maintenance technician, I’d rather have my operators focus on making product.”
Third-party equipment maintenance contractors are an established service industry in the construction business and many composters use them as well for frequent and necessary repairs, such as engine work or repairing flat tires on loaders. “We used to have dedicated maintenance staff, but we’re spread out among 12 sites, so the bulk of our expenses were wages and windshield time,” says Ken Tritz, General Manager of Resource Recovery Technologies based in Bloomington, Minnesota. “We now use third-party service companies for 90 percent of our maintenance work and our ‘mechanically’ savvy operators do light maintenance.”
DIAGNOSTICS AND REPAIRS
Smart maintenance is, not surprisingly, increasingly dependent on computer-based diagnostics and remote troubleshooting. Morbark, a manufacturer of tub and horizontal grinders, has a computer-based IQAN system that offers both process control and a satellite linkage to the factory for diagnosing machine functions in real time.
Similarly, each Backhus turner is designed from the ground up to be self-diagnosing. An array of system status and warning lights are mounted on the console. Each light not only indicates potential problems, but also informs the operator/technician of exactly what problem exists. This is accomplished by a series of blink codes, which when matched with the cross reference in the maintenance manual, will indicate the problem and the recommended fix. Software also monitors the hydraulic system, checking the temperature, fluid level, pressure and level of hydraulic filter contamination. A laptop computer can be connected to the turner to download status, alarm and service files. Adjustments to the engine, hydraulics and operator controls can be made via laptop connection. Remote diagnostics are available via an optional modem, enabling the service provider to communicate with the turner remotely.
Several of the loader manufacturers, like Volvo and CAT, require owners to take samples of the oil when doing 250-hour oil changes and to send those samples in to the factory for lab analysis. “We get a small sample bottle and a postage paid envelope to send the sample in,” says Ken Newman of Royal Oak Farm in Evington, Virginia, who has three Volvo loaders. “We get the lab results back in about one week, and they tell us about abnormal wear, too much dirt in the oil, all sorts of things.”
Knowing what spare parts to keep on hand takes some careful planning. Franciosi recalls that when the facility started in 2005, they went through each equipment manufacturer’s parts list and inquired about the availability of overnight delivery for each part. “All the major equipment guys offer overnight delivery on most parts,” he says, “so we didn’t have to spend cash on spare parts just lying around on a shelf in the shop in the event they’re needed.”
Steve Elliott, who runs the yard trimmings compost facility for Mecklenburg County, North Carolina, keeps all wear parts in stock for the site’s four grinders: bearings, tips, hammers and conveyor belts. “We also keep all filters and fluids for each piece of equipment,” he says. “When we have to order a spare part, we go ahead and buy at least one extra of that needed part. For example, our three loaders were all purchased at the same time and are one serial number apart, so when a part fails on one of the loaders, we’re reasonably sure that same part will fail on another of the loaders in the near future.”
Elliott went on to note that the County’s procurement specifications usually require an equipment dealer be located no more than 50 miles from the composting facility, which he said greatly facilitates getting spare parts quickly.
Craig Coker is a Contributing Editor to BioCycle and a Principal in the firm of Coker Composting & Consulting in Roanoke, Virginia. He can be reached at (540) 904-2698 or by email at firstname.lastname@example.org.
October 25, 2007 | General
Smart Series: Equipment Maintenance
BioCycle October 2007, Vol. 48, No. 10, p. 25