Belt scrapers: From DIY to high-tech
December 11, 2008 By: Bruce Boyers Pit & QuarryFor many in the aggregates industry, belt scrapers are sometimes a do-it-yourself kind of thing. Such measures, such as a piece of conveyor belt material or whatever else might be laying around, are sometimes taken in an effort to save money. But these solutions can be damaging to conveyors.
“I’ve seen everything used for belt scrapers,” said Bob Welker, sales and marketing manager for Argonics Inc. “You often see a piece of conveyor belt attached to a weighted lever system where they’ll have a conveyor idler just bouncing on a chain on the end of a lever to supply the tension. I’ve even seen an old alternator from a truck used as weight, and bungee cords used, as well.”
“Obviously such a rig could break and drop something on somebody,” Welker continued. “Also, an old piece of conveyor might contain steel that actually damages the new belt.”
Obviously belt scrapers are a necessity to keep conveyors clean of material buildup that, if not taken care of, would quickly render the conveyor useless. But modern technology has actually produced belt scrapers that are indeed “state of the art.”
Doug Hammons is a plant operator with Teichert Aggregates, a California aggregate producer. Early in his career, he also used homemade solutions. “We used to make our own with a piece of thick rubber and a big contraption with a counterweight on it,” he recalled. “They worked all right if you placed them just right and paid a lot of attention to them.”
Along with many other cement and aggregate producers, Hammons has long since discovered that when it comes to belt scrapers, there is definitely a better solution. When he took over the Teichert plant, he found belt scrapers being used that were inferior and frequently wore out. “I always like to give everyone a fair chance and try other blades,” he said. “But I had used one kind at my previous company and found them to be the best. We found them to be the superior here, also.”
The belt scrapers Hammons uses are of specially formulated polyurethane, produced by Argonics Inc. “We get at least double the life out of these belt scrapers than any others we’ve tried,” he reported. “And they last far longer than any homemade solution I ever used.”
Polyurethane produces an advanced wear-resistant product that Argonics Inc. says outperforms rubber, metal or plastic, especially in belt scraper applications.
“They’re good enough that we don’t even have to go back and re-tension them,” Hammons said. “We can leave them until the blade gets short and then replace the blade.”
The strength of the belt scrapers used by Hammons is in the proprietary formulation of polyurethane — a formulation that enables the blades to last two to three times longer than others and has the advantage of 60-percent less coefficient of friction than rubber. They also provide reduced drag on conveyors, lowering horsepower use, and the nonporous surface does not collect material that can damage the belt.
The belt scrapers are available in a variety of formulations depending on the application. In addition to the standard scraper, there are also flat dual-durometer scrapers available, in which a harder portion scrapes rough material while a softer portion produces a squeegee effect; a “sandwich” version in which a softer, flexible layer of polyurethane is placed between two harder layers to provide heavy-duty performance with flexibility; and an extremely tough scraper with ceramic wear beads embedded into a polyurethane matrix.
Argonics, Inc., www.argonics.com
Bruce Boyers is a freelance writer based in Glendale, Calif.
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