Global Processing

Measurement accuracy maintained through changes in fluid temperature, density, viscosity

November 14, 2003

A leading soft drink bottler was using positive displacement (PD) flowmeters to measure water and corn syrup. The system, which measured volume, experienced inaccuracies as temperature, fluid viscosity and fluid density fluctuated. The method required time-consuming lab tests and adjustments to each syrup batch. The PD meters also required regular maintenance and periodic calibration, increasing total cost of ownership.
In their syrup room for the blending of high quality simple syrup, this bottler replaced its PD meters with Coriolis mass flowmeters. The complete metering and control system consists of an industrial-grade PC blending system and three meters. A major objective of the system upgrade was to eliminate quality problems related to variations in corn syrup concentration. Since the corn syrup storage tanks are not agitated, stratification occurs. The volumetric PD meters could not compensate for the varying densities. The Coriolis flowmeters offer accurate mass flow measurement regardless of the fluid density. Additionally, they monitor the corn syrup solids content. Exact solids levels of the 42 percent and 55 percent HFCS (high fructose corn syrup) syrups are supplied to the control system from the transmitters and the blend is adjusted accordingly. Soft drink blending, although a relatively simple process, benefits enormously from high technology mass flow and percent HFCS measurement through improved product quality and reduced costs. Quality soft drink production requires a single flowmeter to maintain accuracy on a number of products. Online percent HFCS analysis instruments must be easy to operate and maintain. The equipment and its maintenance must justify the investment, and it must produce a high-quality, consistently reproducible product. In this bottler''s operation, water, HFCS, concentrates and other minor ingredients are blended together to produce simple syrup. The syrup is stored and transferred to a proportioner, then blended with water to bring to final beverage strength. The blend is then carbonated to produce the finished product. The process is simple but inconsistent proportioning of syrup ingredients results in an unfavorable product and poor profitability. In the new system, two 3-inch meters are installed on corn syrup, one for 42 percent and the other for 55 percent HFCS. A sensor is used to measure water. Mass flow rate information from all three sensors and the percent solids HFCS information from the 3-inch sensors are transmitted to the PC. The information is processed and the control system determines the correct syrup blends. This provides accuracy and quality control unattainable with the previous system. In addition, because the mass flowmeters have no moving parts, they don''t require periodic maintenance or recalibration. As a result, the system upgrade not only improved product quality, but is also saving time and money.

For more information, contact Micro Motion Division of Emerson Process Management at 800-522-MASS (800-522-6277).