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food Marketing & Technology 3/2022

food Marketing & Technology is the international magazine for executives and specialists in the food industry.

Cover Story

Cover Story Multi-frequency Flow Measurements for Accurate Raw Material Accounting Meierei Barmstedt (Barmstedt Dairy) eliminates measurement discrepancies caused by gas entrainment with the Promass Q Coriolis flowmeter from Endress+Hauser For many food manufacturers, raw materials accounting is a highly important and frequently discussed topic. The idea behind this thought is to measure the exact amount of delivered raw materials, such as milk, oil or alcohol, and then precisely allocate how much is used in each of the individual production steps. The goal is to provide as much as transparency as possible when it comes to the raw materials used in each and every product – such as cheese and butter at a dairy operation – and to be able to create full cost accounting. The Promass Q Coriolis-based flowmeter from Endress+Hauser offers food manufacturers a one-of-a-kind opportunity to optimize their raw materials accounting with innovative technology. by Manuel Martini & Florian Kraftschik Erroneous volume and mass flow measurements Volume and mass flow are two commonplace terms whose meanings can lead to very stark differences in materials accounting. In contrast to volume, mass flow exhibits a constant behavior when subjected to changing influences such as pressure and temperature. That’s why the accounting systems rely on units of mass in many cases. Many companies nevertheless use volume measurements, which can lead to unwanted differences in the raw materials accounts settlement. But even mass flow measurements have potential sources of errors that users have to take into account. In the field, one of the primary causes of measurement discrepancies relates to undetected air or gas entrainment in fluids, which distorts the measurement value and leads to differences in the raw materials accounts settlement. To prevent this from occurring, Meierei Barmstedt relies on the Promass Q, a Coriolis-based flowmeter that detects Four Promass Q instruments operate side-by-side at the raw milk delivery terminal. All images: © Endress+Hauser 6 food Marketing & Technology • June 2022

Cover Story gas entrainment and lowers the measurement error ratio to nearly zero. Gas entrainment distorts values at the delivery point The dairy’s tank trucks make daily runs from farm to farm to retrieve the milk. Because the trucks are not full at the start of the run, the tank still contains a considerable amount of air. As the truck navigates curves, accelerates and performs braking maneuvers, the milk constantly swishes around in the tank and mixes with the air. This effect has an enormous disadvantage for dairy operators. If volume flow is used as the measurement unit when the milk is retrieved from the farm, it leads to an exaggerated measurement, which in turn exaggerates the amount of raw milk delivered to the dairy. This is because the air has significantly increased the volume. In practice, an increase of 10 percent, or even 20 percent in extreme cases, is not uncommon. This so-called “milk overrun” has a negative impact on the finances. Assuming the air is purged during the production process, the dairy operator ends up posting a loss when settling the raw materials accounts. This also makes it difficult to create accurate full cost pricing. With this in mind, instead of volume flow, many dairy companies use mass flow to measure the amount of milk that is delivered and processed during production. Coriolis systems, such as the Promass family of instruments from Endress+Hauser, have proven their worth in such applications for years now. Unfortunately, unwanted accounting differences can still occur even when Coriolis-based flowmeters are employed. As with volume flow, one of the reasons for this effect is air entrainment, which influences mass flow measurements as well. Although the effect is considerably lower, it still exists and can lead to deviations. When processing large quantities of raw milk like Meierei Barmstedt, small percentage errors add up to significant sums at the end of the year. Multifrequency technology for reducing measurement discrepancies To eliminate discrepancies in the mass flow measurements, Meierei Barmstedt relies on the newest member of the Endress+Hauser Promass family - the Promass Q, an instrument that features the patented multifrequency technology. The Promass Q was designed to eliminate measurement errors induced by gas entrainment down to a level of nearly zero. The unique patented feature of the sensor is that the Coriolis tube oscillates within two superimposed resonance frequencies instead of just one, a major advantage over the conventional Coriolis measurement principle. Measurement errors caused by entrained gas can be virtually eliminated. In simple terms, this has to do with a physical effect in which the relationships between the two stimulated resonance frequencies equate to the relationship of the measurement errors induced by entrained gas in fluids. The oscillation of the two superimposed resonance Gas entrainment levels are highest directly after delivery, the point at which the Promass Q eliminates the measurement discrepancy. food Marketing & Technology • June 2022 7

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