July/August 2015 Consider after-market products and services to enhance conveyor safety and performance.
By Kenneth A. Hooker
Conveyor systems are the workhorses of many scrapÂyard operations, moving materials from intake points through processing stages to storage areas to outgoing shipments. Their specific uses and configurations vary widely from one facility to another, so they are almost always custom installations. Depending on the scrapyard owners’ needs and budgets, the same manufacturer could equip two conveyors quite differently. In every case, though, conveyors that run smoothly, safely, and efficiently can help ensure the success of a recycling business.
Recyclers will sometimes add after-market products to conveyor systems to adapt to new requirements, reduce or facilitate routine maintenance, or increase operator safety. Here’s how scrapyards are using several such products.
Customize Conveyors for Safety
As powerful pieces of equipment that run almost constantly during a work shift, conveyors pose some particular safety challenges. People working near conveyors can easily become careless around them, contributing to serious or even fatal accidents. An arm, a leg, or an article of clothing can quickly get caught in a conveyor’s moving parts, with disastrous consequences. The Occupational Safety and Health Administration (Washington, D.C.) requires that conveyors less than 7 feet above the ground have shields or guards on them to prevent accidental contact with moving parts, but manufacturers do not always supply these guards as original equipment.
“It’s up to the end user to make sure that the proper guarding is in place, and you can’t just assume that the manufacturer will provide it that way,” explains the safety director of a large recycling company in New England. “If you communicate with the manufacturer, they’ll usually help you with that, [but] … often the manufacturer will sell you a conveyor system that just consists of the frame, the return rollers, the belt, the head and tail pulleys, and the motor that drives it, and that’s it. They have no idea how you’re going to use it, whether you’re going to hang it 20 feet in the air, add it on to an existing system, or what.”
This safety director recommends inviting the manufacturer or supplier to come out to your facility to see how you plan to use the equipment. This also will give you a chance to ask for the necessary safety guards. “There will be some cost involved, but maybe less than what you’d pay to fabricate and install everything on your own,” he says.
It’s very rare for guards on the return side of a conveyor to be part of an original installation, according to an Ohio dealer who handles conveyor belts and other supplies. “It’s something you almost always have to purchase separately or at least ask for when you’re buying the conveyor system,” he says.
Such purchases don’t always need to be custom-fabricated, however. Several manufacturers produce after-market guards and cages to prevent accidental contact with return idlers and other moving parts. These come in a range of standard sizes and configurations suitable for different conveyor setups.
When considering what guards to buy, look for evidence that they comply with OSHA requirements. Potentially useful features include slotted designs that can help prevent material from building up within the cage, as well as hinged attachment points that make it easy to open and close the cage for conveyor maintenance.
Other add-on equipment options can stop conveyor systems in an emergency. For example, loader or crane operators should be able to spot trouble on a conveyor and shut it off remotely, says a dealer for the mid-Atlantic region. “There are also personnel-safety systems with switch-equipped vests,” he notes, which trigger the machine to shut off if someone working on the conveyor loses his or her balance and falls. “The vest has a sensor that’s tied in with the [emergency]-stop system on the baler or shredder. It’s also important that the e-stop systems for all components of the system are tied in together—not just the shredder or baler, but the conveyors, too.”
Other emergency stopping systems include pull cords and palm switches, which need to be properly positioned “where a worker can activate them and stop the conveyor if they see something wrong,” says one conveyor manufacturer in Illinois. Some cable stops “run the full length of the conveyor, particularly if there are catwalks along the conveyor inviting someone to walk along the machine. Then it’s wise to have a cable-pull e-stop on the side with the walkway.”
Conveyor manufacturers might not provide the electrical components for conveyor systems, he says, because the end user prefers to use certain brands or is working with an electrician who wants to choose and install them. Thus, you must ensure the installer has included emergency shut-down equipment in his electrical plans.
Simplifying Upkeep Reduces Downtime
Performing routine preventive maintenance is one way to keep conveyor equipment running smoothly and efficiently, but it’s also a chore that a busy recycling facility can sometimes neglect. Automating parts of the maintenance procedure is one option.
You can install central lubricating systems and program them to lubricate conveyor parts automatically at specific intervals, or when you trigger them to do so. Manufacturers cite several benefits to using these automatic greasers: reduced labor, by automating an otherwise manual process; added efficiency, because you can lubricate the equipment while it’s running; and accurate lubricant delivery even in extreme temperatures. They also greatly reduce the chance that your maintenance team will miss a crucial lubrication step.
Keeping conveyor belts clean is another maintenance chore that can help prevent equipment damage and unscheduled downtime, but maintenance tends to be something people get lax with when cutting costs, says a conveyor manufacturer in Missouri. Manufacturers have created after-market products such as hinged guards that are easy to take off and put back in place to make the job easier.
“Some [customers] have added scrapers to help keep the belts clean, or brushes to serve the same function on cleated belts,” he says. “These things can help keep material out of the pulleys, out of the sides, and out from under the belts. There’s a cost to that, too, but [such equipment] can be helpful and can be added later” to spread out the expense.
Others question the value of belt scrapers in recycling operations. One reason is that metal is more likely to get stuck in the conveyor belt, according to the equipment dealer from Ohio. “And when that piece of metal comes around and hits the scraper, it’s either going to take the scraper out and ruin it, or, worse yet, cause the scraper to put a hole in the belt,” he says. “I tell people in the scrap industry not to use scrapers, because it’s not beneficial at all.” Exceptions might be lines that are discharging automobile shredder residue or other products that contain little or no metal, he adds.
Instead of a scraper, he recommends using a simple wing pulley, which “will do a pretty good job of getting the mud and other material off [a belt] before it comes around and gets reloaded,” he says. “A wing pulley is an open pulley with ribs in it, so that when a belt goes around it, the ribs knock off excess material. This is normally considered a standard item, but one company offers an upgraded pulley with chevron-shaped wings that might be added as an after-market item. It’s better at keeping material from getting wedged between the pulley and the belt.”
The manufacturer of this pulley says the chevron-shaped ribs deflect material out and away, reducing the incidence of wings bending and increasing belt life. The company also claims the chevron pulley vibrates less and is much quieter than a conventional wing pulley, reducing noise levels by 50 dB.
Better Belts Prevent Problems
The Ohio dealer calls the conveyor belts themselves the main add-on product for conveyor systems. A fairly basic belt can keep initial costs down, he says; then customers can choose an upgrade when replacing the belt.
“The ones we find the most popular are the single-ply 440 belts. The nice thing about the single-ply belts is that they’re designed to stop lateral rips,” he says. “The carcass will be made of polyester and nylon, basically four layers combined into a single ply. Usually there will be a 1/4-inch top cover made of rubber and a 1/8-inch bottom cover, also made of rubber, to help protect the ply. Most scrapyards can get about a year of use out of that type of belt, if they practice good preventive maintenance. It’s an upgrade I’d recommend to increase belt life, especially for a scrapyard’s No. 1 discharge line, which typically would handle a lot of metal.”
On the other hand, sticking with the same type of belt they used initially might make more sense to some users, the Illinois conveyor manufacturer observes. “In the scrap metal business, you don’t necessarily wear a belt out the way you would in an agricultural environment. Instead, you basically kill it [due to damage] one way or another before it wears out,” he says.
What belt you need will depend on your application, this manufacturer suggests. “With ferrous or frag recycling,” he says, “you’re going to want the toughest belt coming off the shredder—that’s where you’ll have oversized pieces coming out, and they’re hot. That belt will be taking the worst of it, and that’s where you should be considering a heavier carcass. Downstream from there, usually the stuff is split through magnets and air systems … and the burdens are lighter, so it’s not as necessary to put as much money into belts.”
Other types of equipment introduce different challenges for belt wear, he continues. “Where you’re cutting scrap with shears, that’s even worse, because you have giant, heavyweight razor blades, and it’s important that the transition from one machine to another is as smooth as possible,” he says. “It has to be designed so that you don’t have large chunks of scrap nose-diving into belts. Those belts usually need to be a little bit above the ordinary, with a heavier carcass—just heavier all the way around. If necessary, some [of] these belts have to be cleated to prevent rollback, especially when the incline might be a little steeper than ideal.”
Don’t Forget to Cover Up
In some conveyor system installations, it is advantageous to provide covers for all or part of a conveyor’s length. Covers can protect the line against inclement weather—snow and ice tend to be bigger problems than rain. In other facilities, conveyor covers are installed to contain dust, dirt, and fluff the recycling process generates.
Conveyor covers may be site-built structures or products manufactured and sold specifically for that purpose. One such system consists of modular one-half, three-quarter, or full arched sections of corrugated material, available in aluminum; galvanized, lacquered, or stainless steel; and fiber-reinforced polyester, which is mainly used in highly corrosive environments. The rigid covers are typically hinge-mounted along the conveyor structure with no need for additional bracing.
Adding Services Can Enhance Operations
Beyond these conveyor accessories, many providers also offer services to support conveyor performance long after the initial installation. Whether you purchase the conveyor system directly from a manufacturer or through a dealer or distributor, the original supplier generally takes responsibility for overseeing the installation and for training the end users to operate and maintain it.
Some conveyor manufacturers offer customers refresher sessions to train newly hired operators and remind longtime operators of the finer points. Manufacturers and distributors might offer follow-up inspection and maintenance contracts to equipment owners.
“Some of our distributors [have contracts] with their customers to come around periodically and inspect their equipment and make recommendations,” says one manufacturer. “They’ll check on the guards, they’ll check the lubrication, check that they’re cleaning properly, check to see if there are parts that need to be replaced. We think it’s a great idea and wish everybody did it. It is another cost, but I think it pays off in the long run.”
Kenneth A. Hooker is a writer based in Oak Park, Ill.