Quiz Corner: Potential actions to reconcile flow measurements

What potential actions can be taken if a problem is suspected because the measured flow leaving a reactor is higher than the measured flow entering the vessel?

A. Check the calibration of the inlet flowmeter.

B.  Check the calibration of the outlet flowmeter.

C.  Check the calibration of the inputs to the electronics providing the inlet and outlet flow measurements.

Presuming that you are knowledgeable in instrumentation, all of these answers provide direction to troubleshoot the flowmeters and resolve the problem. Answer A, Answer B and Answer C are correct.

Additional complicating factors

The suggested answers are the answers of a person with instrumentation knowledge.

There are times when you might want to consider looking outside the instrumentation box, especially when the instrumentation is known to be calibrated and operating properly. For example, there might be an additional connection providing flow into the reactor. The density of the incoming liquid may be different than the density of the liquid leaving the reactor so their measured volumes may be different. One of the flowmeters is a mass flowmeter, while the other flowmeter measures inferentially. Needless to say, there are many possibilities.

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.