The high viscosity of syrup presents a special challenge for the mass flowmeters used in fruit canning operations. Many flowmeters cause a significant pressure drop as the syrup passes through the meter, decreasing accuracy of the concentration measurement and increasing pump demand.

During a recent upgrade of its production facilities, Signature Fruit Company recognized the importance of installing mass flowmeters that accurately measure flow and concentration and minimize pressure drop. “In general, we were looking for a more efficient and more accurate syrup blending system that was automated and required less labor to operate and improved our sugar usage efficiencies,” says Don Jepson, Ph.D., director of engineering at SFC. “We sought a mass flowmeter that would allow us to deliver uniform pressure to all our filling lines, to maintain product consistency.”

SFC is California’s oldest and largest processed-foods company, annually processing 160,000 tons of peaches, 50,000 tons of pears, 15,000 tons of apricots, and about 10,000 tons of grapes into shelf-stable food products. Now a subsidiary of John Hancock Life Insurance Co., SFC sells its products under the Libby’s and Nature”s Orchard brands, as well as customer-owned labels for the retail, food service, international, and industrial markets.

Production Upgrade
SFC is currently in the process of upgrading its production facility. The upgrade is part of a major initiative to prepare the company for increasing global competition, especially from South America and South Africa. “Our energies have been directed toward selecting the finest growers, implementing strict quality management systems and strengthening our manufacturing core competency,” says David Long, SFC’s president and CEO.

SFC is replacing antiquated batch systems for syrup blending that involved labor-intensive dilutions and manual testing of sugar concentration with sucrose Brix refractometers. The company was using mechanical meters and pumps to measure flow to the mixing operation for bulk syrup, which consisted of canners corn syrup, high fructose, and sucrose.

“Initially, we designed the new automated blending system based on a Coriolis mass flowmeter with a straight-through design involving dual quarter-inch tubes,” says Jepson. “However, this restriction caused significant pressure drops. Moreover, the flowmeter had a limited range, which meant we had to use two meters — one for high-flow and another for low-flow.”

Low Pressure Drop
After a thorough investigation of available mass flowmeters, SFC purchased an OPTIMASS 7000 single, straight-tube Coriolis mass flowmeter from KROHNE ( of Peabody, Mass. “We choose the single-tube design because it creates a lower pressure drop and is resistant to blocking or fouling,” says Jepson.

“The KROHNE flowmeters were the most economical choice for a number of reasons. Because of the low pressure drop, we were able to reduce the size of the meter by a full size compared to the other manufacturer’s meter that we had originally specified,” says Jepson. “The low pressure drop of the KROHNE meters also meant that we did not need to scale up our pumping capacity, and we were able to use more of our current pumps than if we had used an alternative flowmeter design.

“Moreover, the KROHNE flowmeters are extremely versatile,” Jepson says, “allowing us to use a single pump for both high-flow and low-flow conditions, unlike alternative solutions that require multiple meters, with additional piping, fittings, controls, and maintenance.”

Using KROHNE’s patented AST (Adaptive Sensor Technology) design, the OPTIMASS 7000 flowmeter is extremely stable and adaptively tuned, independent of external forces and fluid density. The OPTIMASS 7000 also has advanced electronics, which incorporates front-end signal processing to provide excellent turndown capabilities for measuring low flow. The meters are manufactured from materials specially selected to conform to FDA guidelines, with titanium, stainless steel, and Hastelloy wetted parts.

SFC has purchased 19 flowmeters for use during initial blending of concentrates to achieve bulk product at the desired Brix.

SFC has purchased 19 of the OPTIMASS 7000 flowmeters for use during initial blending of concentrates to achieve bulk product at the desired Brix, which is calculated by the control system’s programmable logic controller from the measured mass flow readings. The meters are also used during a second phase, as the blended syrup is diluted with water and placed into containers with the fruit, with a particular concentration of sugar depending on the attributes of the fruit, the desired taste of the product, and other factors.

Reliability & Accuracy

SFC will be upgrading all of its 45 processing lines with OPTIMASS 7000 meters during the next few weeks.

“Reliability and accuracy were extremely important to us when selecting the KROHNE meters,” Jepson says. “We process the fruit at the moment of peak freshness, and we have a short and intensive processing season that operates only from June through September. Therefore, downtime on any of our lines would be extremely expensive. We have been very pleased with the high reliability of the KROHNE meters.”

Based on the success of the blending automation program, SFC will be upgrading all of its 45 processing lines with OPTIMASS 7000 meters during the next few years.

“The main goal of automating the blending process,” says Jepson, “was to operate more efficiently and with more precision, reducing variation of Brix in the end product from a half percent to one or two tenths of a percent. With the KROHNE meters, we are achieving this goal, delivering a high-quality product and minimizing our syrup purchasing costs.”

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