Food Engineering

Sticky Situation Goes With The Flow

July 5, 2007
Coriolis flowmeters provide accurate and reliable viscous measurement.

The pumping and metering station at SFC uses Krohne’s Optimass 7000 single straight tube Coriolis flowmeter. Source: Krohne.

Signature Fruit Company (SFC) is California’s oldest and largest processed foods business and annually converts 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.  “Our energies have been directed toward selecting the finest growers, implementing strict quality management systems, and strengthening our manufacturing core competency,” says SFC President and CEO David Long.

During a recent upgrade of its Modesto, CA, production facilities, SFC recognized the importance of installing mass flowmeters that accurately measure flow and concentration while minimizing insertion pressure loss.  “In general, we were looking for a more efficient and more accurate syrup blending system that is automated, requires less labor to operate and improves our sugar usage efficiencies,” says Don Jepson, PhD, director of engineering at SFC.  “We sought a mass flowmeter that would allow us to deliver uniform pressure to all our filling lines and maintain product consistency and quality.”

SFC’s antiquated, syrup-blending batch systems involved labor-intensive dilutions and manual testing of sugar concentration with sucrose Brix refractometers.  The company used mechanical meters and pumps to measure flow to a 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 particular manufacturer’s Coriolis mass flowmeter that has a straight-through design involving dual quarter-inch tubes,” explained Jepson.  “However, this restriction caused significant pressure drops.  Moreover, this flowmeter had a limited range, and therefore two meters would be required, one for high flow and another for low flow conditions.”

After a thorough investigation of available mass flowmeters, Signature Fruit purchased an Optimass 7000 single straight tube Coriolis mass flowmeter from Krohne, Inc.  SFC chose the single-tube design because it creates a lower pressure drop and is resistant to blocking or fouling.

The flowmeters, which conform to all FDA guidelines, were the most economical choice for a number of reasons.  Because of the lower pressure drop, SFC was able to reduce the meter’s size, compared to the meter originally specified.  Also, SFC didn’t need to scale up pumping capacity, and therefore, was able to use more of its existing pumps.  And, only one meter is required for high and low flow conditions, reducing the need for additional piping, fittings, controls and maintenance.

SFC has purchased 19 of the 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 at a particular concentration of sugar. In the next few years, SFC will upgrade 45 of its processing lines with the new meter. With an intensive processing season that operates only from June through September, downtime gets very expensive.

“We have been very pleased with the high reliability of the meters,” Jepson concludes.