The plant manager wants to relocate a 2-inch Coriolis mass flowmeter measuring zero to 200 kilograms/minute of water that is no longer needed to another part of the plant to measure the same flow of chocolate. Will this work? If not, what problems do you anticipate?

This could be a tricky question because it involves technical analysis and (potentially) politics.

From a technical perspective, the chocolate is much more viscous than water, so the pressure drop across the flowmeter will be much greater than that for water flow. The pressure drop across the flowmeter can be obtained using the Coriolis manufacturer’s pressure drop curves or software. If the pumping system cannot generate sufficient pressure to achieve full flow, a larger Coriolis mass flowmeter may be required. Given the much higher viscosity of chocolate, it is likely that at least a 3-inch Coriolis mass flowmeter will be needed.

Additional complicating factors

Presuming that a larger flowmeter is necessary and despite your best efforts to explain the technical details, the plant manager may nonetheless order you to install the 2-inch Coriolis flowmeter that will not work properly. If this occurs, I suggest documenting your actions and have the larger flowmeter and its associated piping available on-site (or at least nearby). By the way, we used to call this an “object lesson.”

David W. Spitzer


David W. Spitzer is a regular contributor to Flow Control magazine and a principal in Spitzer and Boyes LLC, which offers engineering, seminars, strategic, marketing consulting, distribution consulting and expert witness services for manufacturing and automation companies. Spitzer and Boyes is also the publisher of the Industrial Automation INSIDER. He has more than 40 years of experience and has written more than 10 books and 350 articles about flow measurement, instrumentation and process control.

Spitzer may be reached at 845-623-1830 or via Click on the “Products” tab to find his Consumer Guides to various flow and level measurement technologies.