I used a clamp-on unit on an 8-inch diesel rundown last week to validate exchanger fouling factors; matched DCS within about 2% when flow and temperature were steady, but readings drifted with minor temp swings and surface rust under insulation. Any recommendations on brands and mounting prep (paint removal, couplant choice, transducer spacing) that keep accuracy stable for short optimization checks?
I’ve had good luck with the Emerson Micro Motion meters for diesel. For a steady reading, definitely clean the pipe surface and use water-based couplant. How critical is the accuracy for your application?
It sounds like you’re on the right track with the clamp-on unit, but I’d recommend checking the ambient temperature effects too. I had a similar issue where the readings fluctuated due to minor changes in the surrounding environment. Using a quality couplant like the one @alana_t93 mentioned can really help stabilize those readings over time.
I’ve found that cleaning the mounting area thoroughly really helps with accuracy. I once had a similar issue where a little surface rust made it feel like the meter was on a rollercoaster. For couplant, I usually prefer using a viscous grease, which seems to hold up better against temperature fluctuations than water-based options.