January 12, 2011
material handling update | Conveyors

Belt-tightening tips for conveyor owners

Belt-tightening tips for conveyor owners

Buying a conveyor is just the beginning of a long and expensive relationship. But there are plenty of things you can do to keep your long-term costs in check.

By David Maloney

My own introduction to the concept of "total cost of ownership" came when I was a teenager. I had my eye on a used '67 Mustang with an asking price of $750, which was roughly the amount I had saved from an after-school job. But when I approached my father with the plan, I got a cold dose of reality. With a car, he explained, the initial purchase price is just the tip of the iceberg. You also have to factor in the costs of gas, insurance, repairs, new tires, and more. Clearly, my $750 wasn't going to stretch far enough.

Unfortunately, many buyers of conveyor systems have the same frame of reference that I did as a 16-year-old would-be car owner. They see only the sticker price. But with conveyors, like cars, the initial purchase is only the start of a long and expensive relationship, says Boyce Bonham, director of systems development at Hytrol Conveyor Co. Buyers also have to take into account installation costs as well as ongoing expenses like energy, preventative maintenance, and repairs.

Although there's no way to avoid these costs altogether, there are still things conveyor buyers can do to minimize the pain, says Bonham, who has extensive experience helping clients stretch their equipment budgets. In many cases, it's a matter of making smart decisions at the outset, when they design the system and choose its components—controls, motors, gearboxes, power transmissions, and the like. If you're planning to buy a conveyor, what should you look for? Bonham offers the following tips for choosing conveyor models and components that will save you money over the long term.

Conveyor design and controls
Of all the costs associated with operating a conveyor system, the biggest component is energy, says Bonham. That's why he advises buyers to make design decisions with energy efficiency in mind. That might mean, for example, choosing a 24-volt DC-powered unit over a less-efficient AC unit—a move that would produce energy savings of up to 50 percent. Choosing energy-saving components may add a little to the initial purchase price, Bonham says, but the buyer will recover that initial "upcharge" many times over.

Another way to save on energy bills is to have the conveyor built with decentralized drive units spread throughout the belt as opposed to choosing a centralized drive, he says. Using decentralized drives allows a conveyor section to shut down temporarily when there's no payload. That alone can save another 10 to 20 percent in energy costs, and that's just the half of it. Because the units aren't running continuously, there's less wear and tear on components, which translates to lower maintenance costs. And since most of these conveyors are built with modular sections, they're less costly to install.

The speed of the conveyor you select will also have a big effect on operating costs. Simply put, the higher the speed, the more expensive the unit will be to operate. That's why it pays to make sure you're buying only as much speed as you'll actually need.

Of course, that can be tricky if you're choosing your conveyor with future needs in mind. In that case, you may want to consider a variable speed conveyor. Variable speed models give growing operations as well as operations that experience wide fluctuations in throughput volume the ability to change the settings according to their needs. Users can simply run the conveyor at lower speeds during non-peak periods, saving substantially on both energy costs and component wear.

If your operation uses conveyors in a variety of widths, choosing systems that use common components could save you a lot of money. Just as Southwest Airlines flies only one type of aircraft to keep parts and maintenance costs to a minimum, conveyor users can keep a lid on costs by using, say, pulleys and bearings that are common to all models. An added benefit is that they'll need less space for storing parts and components. "Everyone's space costs something," notes Bonham.

He adds that another way to keep conveyor maintenance costs in check is to choose models with parts that are easy to replace. "Years ago, for instance, you had to shut down a conveyor to replace a photo eye," he says. Nowadays, conveyors are available with photo eyes that just snap into the wiring harness while the conveyor is running.

Motors
Conveyor motors today come in three basic types: standard, energy efficient, and super efficient. Selecting a super-efficient motor can cut energy use by 3 percent or more, which can easily add up to thousands of dollars of savings over the unit's lifetime.

"Super efficient motors have a very minimal upcharge in the initial cost, but tremendous savings over the life of the system," Bonham says.

Plus, the more efficient the motor is, the better it will stand up to wear and tear. In other words, not only does a super-efficient motor use less energy, but it also has a longer life expectancy than its less efficient counterparts.

Gearboxes
The choice of gear box also affects energy consumption. For example, a worm gear box has an efficiency rating of 50 to 90 percent, depending on how it's applied. In comparison, a helical bevel gear box has an efficiency rating of 95 to 98 percent.

Choosing a more efficient gear box gives conveyor owners the options of using a lower-horsepower motor to accomplish the same task or using the same horsepower motor to run a longer section of conveyor. There's another benefit as well: A more efficient gear box operates with less wear and tear, resulting in a longer life. All of this can add up to energy savings of 8 to 10 percent.

Power train components
Chains and sprockets are the default choice for power transmission in conveyor systems. If you go with chains and sprockets, Bonham says, consider using low-maintenance chains to help control costs.

However, there are more cost-efficient options. One is to replace the chain with a timing belt and sprocket. An even better alternative is to use a direct drive power transmission system. Not only are direct drive units more efficient, but they have no parts to replace, which eliminates the need for maintenance and parts storage altogether.

Many solid returns
As for what kind of payback buyers can expect from choosing energy-efficient components, that's hard to say. Conveyor usage patterns vary widely from one operation to the next, making it difficult to attach a number to the potential returns.

But Bonham stresses that they'll recoup every penny and more. Most users will see a solid return on investment within two to three years, he says, with the prospect of a much bigger payoff over time.

About the Author

David Maloney
Chief Editor
David Maloney has been a journalist for more than 30 years and has been with DC VELOCITY since April of 2004. Prior to joining DCV, David was senior editor for Modern Materials Handling, where he reported extensively on distribution and supply chain operations. David also has extensive experience as a broadcast journalist. Before writing for supply chain publications, he was a journalist, television producer and director in Pittsburgh. David combines a background of reporting on logistics with his video production experience to bring new opportunities to DC VELOCITY readers, including Web-based videos highlighting top distribution and logistics facilities, Webcasts and other cross-media projects. He also is the host and producer/director of Move It!, DC VELOCITY's online program that explains "how the stuff we use everyday gets to us." David continues to live and work in the Pittsburgh area.

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