About 10 years ago, I was asked to audit the flowmeters used to bill a chemical plant for its steam consumption. In general, hiring a consultant to audit the flowmeters illustrates the importance placed on having accurate measurements that ensure the multimillion-dollar annual steam bill is as accurate as possible.
This activity makes financial sense because hundreds of thousands of dollars of steam can flow through one flowmeter annually. A measurement error of 1 percent will cause the flowmeter to be in error by thousands of dollars per year. Spending a few thousand dollars to have the flowmeter installations, operation and maintenance audited can be money well-spent, especially when conflicts between parties can be prevented before they even start. That said, most people do not think this way, so I typically get involved when something is wrong or when the parties are fighting – or both.
In this case, something was wrong because the “As Found” quarterly calibration check on a flowmeter was almost always in error despite acceptable previous “As Left” calibrations. The usual fixes had already been implemented to include switching and then replacing the transmitter, yet the error continued. Nothing seemed to work. Recognizing that a problem existed and hiring a consultant to audit the system was suggested.
Keep in mind that measurements are implemented using a flow measurement system where the key word is “system.” While problems often lie where the symptoms occur, it is not uncommon to stumble across problems located in other part(s) of the flow measurement system. For example, the flowmeters may not have sufficient straight run, or the pipe diameter is not per specifications, or the flowmeter is coating, or the calculations are incorrect, or the input electronics are set up incorrectly, etc. Hundreds of problems can potentially exist in the flow measurement system.
More next month.
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 spitzerandboyes.com. Click on the “Products” tab to find his Consumer Guides to various flow and level measurement technologies.