Process Noise and Magnetic Flowmeters in the Pulp and Paper Industry, 1993 Process Control, Electrical & Information Conference Proceedings

David L. Wehrs

Pulsed DC magnetic flowmeters have become a mainstay for flow measurement in the pulp and paper industry in the past several years. DC technology’s advantages of higher accuracy, superior zero stability, and improved reliability have been repeatedly demonstrated. However, numerous users have found applications where, because of high levels of process generated noise, DC magmeters have performed unacceptably, forcing these users to resort back to the older AC technology. Manufacturers of DC magmeters have recognized these shortcomings and in the past few years have introduced new designs which have performed better than their DC predecessors, but certain applications have remained the domain of AC magmeters. These tough applications and the unique characteristics of the noise generated in each is examined. A new type of DC magmeter is discussed which combines the advantages of both technologies. The performance of this meter versus AC magmeters in real life pulp and paper applications is presented.