Calibrating load cells
by Shane Whitaker
At this year’s Tortilla Industry Association’s annual conference, Darrel Fround, general manager of Tyson Mexican Original, a division of Tyson Food, Inc., Springdale, AR, pointed out that plants need to get true, accurate weights of ingredients and recommended they calibrate scales for incoming bulk ingredients as well as packaging scales to ensure they are not giving away product.
Newer silos are often built on load cells, so bakers can keep a precise account of how much of their bulk ingredients they have on-hand as well as measure incoming shipments when they are unloaded.
“Bakeries can negotiate with their suppliers to pay for only what is delivered to their silos or tanks,” said Bill Kearns, vice-president of engineering at The Fred D. Pfening Co., Columbus, OH. “This may be done by having the silos or tanks on load cells and periodically calibrated. Provisions must be made so that plant operations do not disturb the weight during the filling process.”
Load cell calibration can be done more easily if the tanks and silos are fitted with built-in brackets for the test weights and proper access is provided for fork trucks to move the weights around. “Silo test weights are typically 1,000-lb steel blocks, so they require equipment to be moved around,” Mr. Kearns said.
Because of the difficulty involved with calibrating load cells on flour silos, these systems are generally not checked on a monthly basis but annually or biannually instead. In fact, bakers can use many different approaches to how often they calibrate load cells in other processing areas as well, according to Jason Stricker, account executive, Shick, Kansas City, MO. He noted that some bakeries will calibrate load cells annually, while others may perform this task monthly. If they are doing that often, he said, they will often train someone on staff to perform these checks — but official certification has to come from a scale company.
To ensure that excess amounts are not introduced to the process, K-Tron’s batch weigh receiver is specifically designed not only to transfer bulk materials but also accurately weigh them, said Sharon Nowak, global business development manager, food and pharmaceuticals for the Pitman, NJ-based company. “This saves on both quality of the product and ingredient costs,” Ms. Nowak said. “Even the improvement of just 0.5% accuracy in batch weight delivery can cause significant overall savings.”
For lines needing faster automation or wanting to scale multiple ingredients at once, AZO, Inc., Memphis, TN, can design hoppers with buckets built inside for weighing minor ingredients. “The minor buckets will have their own individual scales,” said Russell Nadicksbernd, system sales for AZO Food, a division of AZO, Inc.