Because all mag meters share a common technology based on Faraday’s Law, their operation is reliable and relatively unaffected by turbulence-inducing conditions. Different product construction formats, however, create performance characteristics that make some designs better suited for certain applications.
Full-Bore Mag Meter
This design creates an electromagnetic field within a pipe cross-section to deliver to greater than or equal to 0.5% flow measurement accuracy. As a non-invasive design that leaves the pipeline cross-section completely unobstructed, it accommodates fluid ranging from clean water to wastewater influent and even waste-activated sludge. While its flanged format is reasonably convenient to install in new construction, replacing it or removing it for calibration in a continuous operation can become problematic and expensive, especially as pipeline size increases (Figure 1). This can become even more difficult in vaults and other hard-to-access locations, and particularly is challenging for large line sizes.
Full Profile: Insertion Mag Meter
This design senses flow at multiple locations across the full diameter of the pipe to deliver long-term accuracy to greater than or equal to 0.5% in clean water conditions (Figure 2). Hot-tap installation and maintenance convenience can save 45% on installation and total cost of ownership as compared to full-bore mag meters.
Single Profile: Insertion Mag Meter
While affordable, single-profile insertion mag meters do offer hot tap convenience, their single measurement location limits accuracy to greater than or equal to 2% of scale because it cannot account for flow variations across the entire cross-section of the pipe (Figure 3).