Issue link: https://www.e-digitaleditions.com/i/1325722
January 2021 / 49 install them quickly without com- plaints. If we ever get wear in an elbow anywhere in the plant, we'll replace it with one of these elbows." In more than 16 years since the installation of the deflection elbows, UOSA's facilities have yet to have a blowout. Maintenance and labor costs have been reduced, safety and air quality have been upgraded, and the buildings are visibly cleaner. "We haven't changed out any of the elbows since installing them," says Forgione. "We checked the metal thicknesses of the elbows some years ago and found no reduction, so we believe we're good for a very long time." PBE For further reading Find more information on this topic in articles listed under "Pneumatic con- veying" in the article archive on PBE's website, www.powderbulk.com. HammerTek Bethlehem, PA 610-814-2273 www.hammertek.com The proprietary elbow has a spherical chamber that protrudes slightly beyond the desired 90- or 45-degree flow path, causing a loose ball of material to rotate slowly in the same direction as the airstream that propels it, gen- tly deflecting incoming material around the bend. Self-renewing, the ball gradually releases material in a first-in first-out progression, pro- moting directional change without affecting system pressure. Forgione tested the deflection elbow for more than a year and, after finding no signs of wear, replaced all pebble lime elbows at the facility. Five 45-degree, 4-inch- diameter elbows were installed where the trucks off-loaded their lime and 12 90-degree, 4-inch- diameter elbows were installed at the tops of the silos. A custom alloy for the elbows was specified based on characteristics of the pebble lime and the length and velocity of the pneumatic conveying system. "With new deflection elbows, we've eliminated the primary source of lime dust along with the hazardous conditions it creates," says Forgione. "The delivery was fast and our mechanics were able to for every elbow type that plant personnel tested. Iron elbows lasted nearly a year, and longer, 10-foot- radius long-sweep elbows were able to last 18 months. The plant also tried wear-back elbows, which allow users to replace just the outer radius portion that's made thicker than the elbow itself. However, wear-back elbows eventually wore down and the plant wanted some- thing that would last as long as the straight pipe lengths. "We hit a brick wall," Forgi- one says. "We needed to make the elbows last longer and we needed it done fast." Forgione learned about a deflec- tion elbow from HammerTek, a pneumatic conveying elbow sup- plier, that had been installed at a nearby wastewater treatment plant to solve an identical lime handling problem. A UOSA process con- trol engineer and the mechanical manager toured the other facility and found that the plant hadn't had a single elbow blowout since installing the manufacturer's Smart Elbows. The team also noted the cleanliness of the facility, highlight- ing the potential benefit of stopping the blowouts and leaks for good. The plant has gone 16 years without an elbow failure after installing short radius deflection elbows on its pneumatic conveying lines.