After moving abrasive materials through the asphalt plant, you’ll see minute changes in equipment settings. To continue producing quality mixes on spec, you want to ensure all components stay in calibration. All photos courtesy of WEM Automation
THREE TIPS FOR SUCCESSFUL PLANT CALIBRATION
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BY JOE HIGGINS AND TED CHRISTIAN
Our asphalt plants produce many thousands of tons of asphalt each year, with few breaks in the action available during the peak season. Moving hard, dusty, and abrasive materials like virgin aggregates and reclaimed asphalt pavement (RAP) through a plant takes its toll on your equipment. Things naturally will change and move over time. It’s inevitable. Therefore, it is important to ensure your plant is calibrated properly to produce the consistent, quality product you are after. A well-executed calibration process not only saves you time, but it can also draw your focus to areas of your plant that need attention or items that need to be replaced. Before you start up your plant for the season (or shut down for routine maintenance in warmer climates) here are a few calibration tips to help keep your plant operating efficiently and effectively.
CHECK YOUR VIRGIN AGGREGATE AND WEIGHBRIDGE ALIGNMENT
It becomes an enormous, if not almost impossible task, to get a well calibrated and “dialed-in” plant if we aren’t certain our virgin aggregate and 40 | MARCH/APRIL 2022
RAP weighbridges are in proper alignment. These weighbridges are the primary determining factor of a successful plant calibration and achieving your desired results. Always start here and give this critical area an adequate amount of your time and focus. Make sure to complete the work on your weighbridges before you start tackling your liquid asphalt cement (AC) flow calibration procedures. If you don’t, you may find yourself revisiting and reworking things on your plant and performing calibration procedures more times than you care to. Always make sure of your weighbridge zero values and calibration accuracy before chasing AC variances in production. Remember, all other materials and setpoints rely upon aggregate weighbridge accuracy. At times, verifying that your idler roller alignment is within acceptable tolerances on your weighbridges can seem a bit tedious, but it is essential. Even a variation of 1/16 of an inch beyond the recommended settings can have a significant impact on proper flow and the composition of aggregate material reaching the drum.
