Quiz Corner: Tank level calculation
A differential pressure level transmitter is located 3 feet (36 inches) below the tangent line of a round flat-bottom water tank that is 30 feet (360 inches) tall and vented to the atmosphere. Approximately what is the tank level when the measured differential pressure is 66 inches of water column?
A. 8%
B. 10%
C. 12%
D. 60%
The differential pressure transmitter should be calibrated for 36 to 392 inches of water column. The 66-inch raw measurement represents a tank level of 30 inches (66 minus 36). This 30-inch tank level is approximately 8.33% level (30 / 360), so Answer A is correct.
Additional complicating factors
The analysis does not take into account density changes that occur when the water temperature changes due to ambient temperature conditions during daily and seasonal operation.
David W. Spitzer is a principal at Spitzer and Boyes, LLC, which offers engineering, focused market research, writing/editing white papers, strategic marketing consulting, distribution consulting, seminars and expert witness services for manufacturing and automation companies. Spitzer has written more than 400 technical articles and 10 books about flow measurement, instrumentation and process control. He can be reached at 845-623-1830 or via spitzerandboyes.com.
David W. Spitzer
David W Spitzer’s new book Global Warming (aka Climate Change): An Understandable Data-Driven Explanation and Pathway to Mitigation (Amazon.com) adds to his over 500 technical articles and 10 books on flow measurement, instrumentation, process control and variable speed drives. David offers consulting services and keynote speeches, writes/edits white papers, presents seminars, and provides expert witness services at Spitzer and Boyes LLC (spitzerandboyes.com or +1.845.623.1830).
