ISA Interchange

AutoQuiz: How to Install an Electromagnetic Flowmeter

Written by Joel Don | Aug 11, 2017 1:00:15 PM

AutoQuiz is edited by Joel Don, ISA's community manager.

Today's automation industry quiz question comes from the ISA Certified Control Systems Technician (CCST) program. Certified Control System Technicians calibrate, document, troubleshoot, and repair/replace instrumentation for systems that measure and control level, temperature, pressure, flow, and other process variables. Click this link for information about the CCST program. This question comes from the Level I study guide, Domain 3, Troubleshooting. Level I represents a professional who has a five-year total of education, training, and/or experience.

One of the most important considerations of the installation of an electromagnetic flowmeter is:

a) the Reynolds Number of the fluid
b) the use of a straightening vane
c) bonding the flowmeter to the piping
d) observing the correct polarity
e) none of the above

The concept of a magnetic flowmeter is that when a conductor (the fluid in the pipe) moves through a magnetic field, a voltage is produced in the conductor that is relative to the speed of the conductor and the magnetic field.

It is imperative for the electric circuit to be complete to be able to measure the voltage, which is proportional to the speed. Knowing and multiplying the speed of the fluid by the cross sectional area of the pipe gives the volumetric flow rate.

If the bond between the meter and the piping is not good, the electricity will not flow and the measurement cannot happen.

The best answer here is "bonding the flowmeter to the piping," answer C.

Image Source: Wikipedia