Issue link: http://read.dmtmag.com/i/75471
Dirt and fines can contaminate bearings and cause unplanned downtime on conveyor systems. New bearing technology helps resolve age-old conveyor challenges. by James A. Oliver and Joe Esmoer BEARWith It W hile bulk conveyors routinely carry heavy loads for the aggregate indus- try, they can carry daunting operat- ing challenges along the way, too. As an all-too familiar example, the ingress of dirt, sand, and grit at critical rolling bearing positions, historically, has caused production headaches when contaminants first damage bearing housing seals, then invade the bearings, and, ultimately, subject conveyor systems to unplanned shutdowns costing thousands of dollars and tons of time. The problem can often be traced to the tradi- tional use of unsealed, open-type bearings with standard housings and seals in a conveyor head and tail pulleys and take-up pulleys (among other loca- tions). These types of bearings and housings offer little, if any, protection from abrasive contaminants, prompting some operations to respond by pumping large quantities of grease continuously into a bear- 41A AGGREGATES MANAGER DIGITAL EXCLUSIVE August 2012 ing's housing as a first line of defense. While this re-greasing may help, somewhat, in the short term, downsides can develop over the initial cost of lubri- cant and subsequent issues and costs associated with increased labor, need for constant lubricant disposal, and potentially adverse environmental impact. An increasingly popular alternative is to operate unsealed, open-type bearings mounted in a split housing equipped with contact or auxiliary taconite seals. This offers improvement over minimally protected open bearings in standard housings, but space limitations may be a problem as taconite seals can be relatively costly and may increase the axial length of an assembly. These seals can also pose difficulties in achieving proper alignment. The encouraging news is that leading manufac- turers in the rolling bearing industry have contin- ued to develop more advanced technologies to help keep conveyors up and running.