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When Weighing and Counting Accuracy are Paramount Depend on an Analytical Balance
When Weighing and Counting Accuracy are Paramount Depend on an Analytical Balance
Precision weights and counts are critical across a broad range of businesses. Examples include research labs where processes are developed to manufacture pharmaceuticals and food products. Laboratory technicians rely on an analytical balance to develop processes and procedures that later move to commercial production.
South Orange,
New Jersey,
United States of America
(prbd.net)
11/05/2010
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There’s a great scene in Rain Man where Raymond the autistic savant (Dustin Hoffman) knew how many toothpicks fell on the floor. He kept saying 82. His brother Charlie (Tom Cruise) commented that there were more than 82. Raymond then says “246 total.” Charlie: “How many?” Sallie Dibbs (Bonnie Hunt) reading from the box: “250.” Charlie: “Pretty close.” Sallie: “There’s four left in the box.”
This admittedly is a simplistic introduction to the serious topic of accuracy in weights and quantities. Precision weights and counts are critical across a broad range of businesses. Examples include research labs where processes are developed to manufacture pharmaceuticals and food products. Laboratory technicians rely on an analytical balance to develop processes and procedures that later move to commercial production.
Enter the Versatile Analytical Balance
You will not find a precision analytical balance on the production floor. These weighing and measuring instruments are found in the lab and protected from vibration, air flow and temperature fluctuations that can impair accuracy – especially critical for high-end models with readouts to 0.01 milligram and linearity (± from the actual load) to ±0.15 milligram. So sensitive are some of these instruments that they are capable of weighing loads as low as 1 milligram. At the other end of the scale, the maximum weight for an analytical balance can be several hundred grams.
The Talented Analytical Balance
Raymond’s toothpick count provides an example of what an analytical balance can do. Piece counting is done by first manually counting out the number of pieces desired for a particular process then establishing the weight of that count. The balance can be set to display either the number of pieces or their weight.
Tolerance weighing, also called check weighing, enables laboratory technicians and researchers to program in a ± deviation from the target weight. In some models of analytical balances pilot lamps show red when the load is below, yellow for above and green for “right on” the set limit. Other models emit acoustic signals. Deviations from the target weight can also be displayed as a percentage when the target is set at 100%.
When objects being weighed or counted are placed into a special container, the weight of the container (tare weight) must be accounted for. This is accomplished by setting the balance display to zero when the empty container is put on the weighing platform. Net weight is recorded when the product is placed into the container.
Keeping it Honest
The FDA and other regulators have a keen interest in the accuracy of analytical balances. Procedures apply for initial calibration and regular recalibration of these precision instruments. High-end models automatically recalibrate under certain operating conditions, while others are manually recalibrated using external weights. What all users must also remember is that an analytical balance is a delicate instrument and should not be moved without taking proper precautions to protect the weighing mechanism.
Important, too, is GLP and ISO record-keeping. This is accommodated by connecting the analytical balance to a PC and a statistical printer using, for example, an RS 232 interface.
About
Tovatech is a distributor of laboratory equipment to the US, Canada, and Mexico. The company specializes in digital scales, pharmaceutical laboratory equipment and ultrasonic cleaners. Tovatech is staffed by chemists and engineers dedicated to providing the right equipment for the food, drug, chemical, healthcare, and equipment manufacturing and maintenance sectors.
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