Smart Elbow® deflection elbow keeps environment clean

February 4, 2014 by Miaja Cornelius

There’s something odd about an industry that’s designed to be good for the environment having environmental concerns of its own. Yet that’s just what was happening at Montgomery County’s North Incinerator plant, which converts household waste to energy in the Dayton, Ohio, area. Try as they did, engineers could not find a way to convey powdered lime — part of the plant’s phase pneumatic conveying system — for any great length of time before a sweep elbow failure resulted in a plant shutdown and expensive cleanup operation.

Finely powdered limestone is injected into all three incinerator units at the plant to meet EPA air pollution standards for sulfur dioxide emissions. Long-radius, stainless steel sweep elbows were utilized in the system, but even these high-strength elbows suffered extreme wear from the highly abrasive limestone — resulting in a sweep elbow failure every three months on average. At the pressure required to move 18,000 pounds of powdered limestone 24 hours a day, 365 days a year, even a pinhole-sized leak in a sweep elbow would create a tremendous cloud of dust, Plant Manager Dave Martin said.

Every 90 days or so, an elbow would fail, spewing surrounding equipment and materials with powdered limestone, requiring an immediate shutdown for repair and cleanup. And the clock was ticking: If the shutdown lasted more than a few hours, the EPA required a complete incinerator shutdown — resulting in a downtime expense of approximately $40,000 per day. There seemed to be no solution to this problem until Martin himself discovered HammerTek’s Smart Elbow deflection elbow at a trade show.

Martin learned that unlike traditional sweep elbows, which invite collisions between conveyed material and the elbow wall, the Smart Elbow deflection elbow is designed to eliminate such wearing impact, promoting directional change without adversely affecting system pressure. Its secret is the patented vortex chamber at the back of the elbow. At a point where traditional elbows fail, the Smart Elbow design creates a rotating ball of suspended material that helps redirect the entire product without friction, impact or wear. Smart Elbow units are also easier to install, requiring much less physical space than long-radius sweep elbows.

Now, not months, but years later, there have been no new surprise dust clouds. That first Smart Elbow model is still in operation, and the plant is utilizing additional Smart Elbow units in its new, higher-capacity lime injection and fly ash handling systems.

“Since installation of the Smart Elbow deflection elbows, we have saved on maintenance costs, decreased our downtime, and increased system reliability,” Martin said. “And we don’t have to cut and weld like we did with the sweep elbows — they just bolt right in.”