May/June 2016
Vibratory feeders can help you shake out better value from the material you are already running through your scrapyard—but only if you have the model that is right for your operation.
By Megan Quinn
Whether it’s ASR, mixed metals, or plastics, vibratory feeders can accurately maintain the stream of your material and shake it safely and evenly onto another conveyor or sorter. Vibratory feeders use a vibrating force to meter out a precise amount of product. That evenly spaced flow makes it easier to separate tangled-up bits of wire, differently sized pieces of metal, or other materials.
A vibratory feeder can be an investment, but manufacturers say it will help scrapyards get better yields from the materials that already come through the yard. “When the economy is down, you want to get as much out of the material you already have,” says a marketing representative from an Illinois manufacturer. Scrap facilities use vibratory feeders for many applications, including for automobile shredder residue, she says. When bits of wires, plastic, metal, and dirt shake into more uniform, separated items, it can be easier to see, identify, and recover valuable commodities from the otherwise-clumped stream. “When all those tangly parts come apart, it’s separated in a way that is better presented to an optical sorter, for example,” she says.
Regardless of the application, vibratory feeders can be a valuable complement to machinery you already own, such as sorting machines. “It increases the value of your product,” says the vice president of sales for an Ohio manufacturer. “When you have a vibratory feeder, it thins out the material, which allows the [sorting] machines to be much more accurate.”
The Right Model for the Right Job
Vibratory feeders are designed for a wide variety of purposes and industries—everything from gently shaking baby carrots or candies onto a conveyor at a food packaging plant to handling the metal or plastic that falls through the grates of an auto shredder. Though manufacturers have some standard models to choose from, vibratory feeders generally are custom-made for your unique application. That’s why it is important to take into consideration a list of factors that will match you with the best machinery for your job.
Type and size of material. Are you dropping ferrous or nonferrous metals onto the feeder? Automobile shredder residue? Plastics? Even cement or gravel chunks? The type of material you handle—and how large each piece tends to be—is an important factor when determining the right model. Some scrapyards might need a heavy-duty feeder to handle ferrous scrap, while others may need to handle lighter-density nonferrous material or ASR. A Pennsylvania manufacturer that makes vibratory feeders suitable for materials such as metals or glass offers a selection guide and a hotline to help answer your questions about matching your feeder to your material. Another manufacturer in Illinois says it recently released a new feeder designed to enhance the recovery or purity of scrap metals.
Capacity and speed. What is the typical volume and weight of material you need to process, and how fast should the material move from the feeder to its next destination, such as a conveyor or sorter? Do you need to move 10, 100, 300, or 1,500 tons an hour? Check with the feeder’s manufacturer to make sure it matches your requirements. Some larger models made for scrap applications may start at 80 tons an hour and go up to as much as 1,820 tons an hour or more, depending on the material’s size and shape, the Pennsylvania manufacturer says.
When deciding what size feeder to get, know that the volume of material and the size of the pieces also can affect the price, says a representative from an Oregon manufacturer. For example, a small operation processing about 10 tons an hour might consider buying a new feeder that can handle twice the capacity in case the operation expands. Yet scrapÂyards should take a close look at the math before making that purchase, he says, because the larger feeder could cost twice as much as one that fits the existing demand. “You really need to know your application and know your budget. From my experience, people sometimes overexaggerate their capacity requirements, so you need to be realistic about the type and amount of material you’re really handling.”
Amplitude and frequency. How forcefully and rapidly does your feeder need to shake in order to achieve the best separation? Material that makes its way across a vibratory feeder might look like it’s flowing along in a uniform stream, but it’s actually making a series of very small “jumps” where each piece bounces ever so slightly toward the end of the feeder. Depending on the model you choose, you might be able to adjust your feeder’s amplitude and vibration frequency to decide how your material jumps and how far forward it throws the material. Base those adjustments on how big your material is and how fast you need the material to move forward from the feeder to its next destination. Yet you also should calibrate your feeder so the vibration best separates your material without clumping it back together or throwing it around unnecessarily. If you’re replacing your current vibratory feeder, you may already have a good idea of how much your material needs to be shaken up, but since newer models might have different features or adjustments, manufacturers say it’s important to discuss those details with a sales rep or service department so your new machine is just as well-calibrated.
Material destination. Once the material leaves the feeder, where is it going? Many manufacturers make feeders designed to work well with other equipment. One Ohio manufacturer, for example, makes a double-magnet feeder that meters the material so the magnet can remove ferrous material, but it also makes a feeder designed to fit well with some types of sensor sorters.
Environment. Most vibratory feeders are meant for plenty of wear and tear. If you are working in environments that are very hot, cold, rainy, or dusty, however, make sure your feeder can handle those conditions. These factors can sometimes affect the machine or the product that hits the vibratory feeder. For example, wet conditions might make some of your material more sticky, which affects how well it meters, manufacturers say.
Cost. With such diverse factors come diverse costs. Smaller, lighter-duty models could start at just $10,000, but they might not work for many scrapyard applications. Undermill vibratory feeders could be between $50,000 and $100,000, but that price could be higher or lower depending on the size of the feeder, its output, and whether you require larger motors or multiple motors.
Energy Savings
The vibratory feeder’s function hasn’t changed much in the last 20 years, but some newer models aim to reduce the amount of energy it takes to vibrate your materials down the chute or pan. If energy costs are among your concerns, ask about models that may use less energy to achieve the vibratory intensity, speed, and capacity you need.
Several manufacturers say their two-mass (sometimes called indirect-force or natural-frequency) feeders are good for energy savings without affecting your daily operations because they typically have a single motor that uses less horsepower to do the same amount of work as a model with two motors. The Pennsylvania manufacturer says its two-mass feeders use a smaller force, which is amplified through a spring, to generate the required vibratory motion instead of attaching the motor directly to the pan. Instead of using a 10-hp motor, one of its two-mass models could do the same job with a 2-hp motor, it says.
These two-mass models differ from a brute-force or single-mass model, which sometimes uses two motors mounted directly to the feeder pan. Brute-force models typically have more horsepower and work well for heavy impacting applications, the Pennsylvania manufacturer says. These models use more energy and experience a decrease in power when heavily loaded. These models also could be prone to higher stress and wear forces, the Illinois manufacturer says. Yet many manufacturers still offer brute-force or twin-motor feeders, in part because the design has been around for many years, making it a familiar style for operators to use that is considered less expensive to purchase and easy to repair. The Ohio manufacturer says it has improved the traditional design by making some of its brute-force feeders lighter than previous models, which reduces stress and makes them more reliable because they need less force to operate.
Testing Your Material
There are two valuable ways you can make sure you buy the correct feeder for your uses: Either borrow a model straight from the company, or send the company a sample of your material so it can run it through different machines.
Ask manufacturers if you can have a trial period in your facility for your feeder once you pick a model you think you like. That way, you can accurately test-drive the model’s capabilities for your yard’s specific environment and needs. “Testing it out and getting the hands-on knowledge helps you know the difference” about which models will work better, the Illinois sales representative says.
If it is too much work or not logistically possible to try out a feeder before buying it, consider asking your sales representative if the company offers off-site testing instead. The Illinois manufacturer says many feeder manufacturers have testing labs that will take samples of your materials. This option, she says, is much more popular with her customers than borrowing an entire unit. “We have a lab and R&D so we can check it for you,” she says. Depending on the application, the company will send back a video or a document with a process warranty. In some cases, you can come and watch the testing, too. A resource recovery director for the Illinois manufacturer says his company more commonly tests for density separation or to determine how materials behave in “more challenging environmental conditions.”
Other vibratory feeder manufacturers or distributors also tout this testing service as a great way to see results without having to commit to a model right away. The Ohio manufacturer asks for 1 cubic foot of material, which it can return to you after testing. Regardless of which option you choose, manufacturers say they offer these services for a good reason: So many factors go into finding the right feeder, and materials vary so widely, that testing often is a necessary part of the calibration process. “We don’t want people buying something they end up not needing or liking,” the Ohio salesman says.
Proper Care and Maintenance
Vibratory feeders typically have a simple design, and “without so many moving parts, service should be minimal,” the Ohio salesman adds. A properly maintained vibratory feeder could last about 15 to 20 years, possibly even longer with the right maintenance, manufacturers say. Like any other piece of equipment, wear and tear varies depending on how often your vibratory feeder is on, how often it moves material, and what types of materials it handles. Keep an eye out for needed repairs, even if those repairs seem more minor than what other machines in the yard require. At the very least, remember to replace the wear liners and to keep the motors greased, says the chairman of a Texas-based shredder company that supplies scrap shredders, processing equipment, and replacement parts. “All of them have some bearings and some electric motors that need routine attention to be kept lubricated and clean, but that is not excessive” in terms of maintenance requirements, he says. This maintenance pays off for daily operations, but also when it’s time to either sell or repurpose your equipment, he says. A used feeder or conveyor “has a good value and can easily be adapted for a slightly different application.”
Vibratory feeders are meant to be somewhat quiet by design, so an out-of-place sound might be a sign of a loose bolt or another problem. Be sure to listen for uncharacteristic clanging, ticking, or tapping from the springs on the feeder, the Oregon manufacturer says.
When buying your vibratory feeder, ask the manufacturer or distributor about maintenance and repair services, such as whether the company has a full-service repair department that can easily respond to your repair needs. Some companies also offer training classes to help scrapyards make the most of their new vibratory feeders. Even if you already know how to operate your current vibratory feeder, a class can help teach you the ins and outs of a new model and help you avoid mistakes that can reduce the value of your material or cause accidental damage, the Illinois marketing manager says.
Other manufacturers have tried to reduce the need for repairs by making their vibratory feeders hardier than previous models. The Ohio salesman says his company changed how it mounted the motor to the feeder, for example. In older models, the motor was mounted directly to the feeder, so if the feeder cracked, the entire machine had to be replaced. Newer models have a bolt-in mounting plate, which absorbs most of the stress. “Now, if there is a crack, it’s in the [plate], and you don’t have to replace the whole thing.”
Yet even the toughest feeders can experience damage when misused, manufacturers say. One common misuse is to overfill the hopper above the feeder or overfill the feeder itself. That can cause the system to clog or work more slowly, and it may not result in an even, well-separated layer of material. That might mean your sorter system will miss critical pieces of material, resulting in lower returns.
The Illinois marketing manager says her company has found a way around this problem by using a two-mass design for some of its larger vibratory feeders to compensate for various loads. When weighted down with extra material, the two-mass feeder still meters out a uniform amount because it uses reactor springs to transmit the force, which dynamically changes the displacement based on how the material is loaded. A brute-force feeder, on the other hand, might stop conveying material or back up when it is too full.
Vibratory feeders are highly customizable machines that can deal with a wide range of materials and loads in various volumes and environments. When you know your specific needs, a vibratory feeder company should have a good chance of creating the right machine for you, says the resource recovery director for the Illinois manufacturer. “The better you know your application, and the better you can define it, the better your equipment manufacturer can provide you with the proper feeder for your needs,” he says.
Megan Quinn is reporter/writer for Scrap.