Our reader surveys indicate that where possible and practical, users continue to move away from mechanical and electromechanical instruments towar electronic transmitters with few or no moving parts to stick or wear. Hence the growing popularity of Coriolis, electromagnetic, vortex and ultrasonic flowmeters in recent years. Dramatic advances in ultrasonic technology in particular have spiked their broader use even in gas custody transfer applications. Thermal dispersion mass flowmeters, too, remain an imporant option for a specialized range of gas measurement applications.
On the level measurement side, this non-mechanical trend is indicated by the increased use of radar, ultrasonic and even sonic profiling gauges that offer a three-dimensional view of solids level in tanks and bins. Fiber optic probes developed for undersea oil and gas applications are measuring flowrate and composition with temperature and pressure to boot. Guided-wave radar, too, is an increasingly popular technology that falls into that category of minimal moving parts: only the float is free to move along a wave-guide probe.
But the number one flow and level measurement technology actually measures neither. Indeed, the differential pressure transmitter remains the most commonly applied flow and level measurement device—in no small part because engineers are so familiar with it.
Sure, a differential pressure cell paired with an orifice plate or other primary element can make for a relatively complicated installation (although pre-integrated assemblies are making this less troublesome) as well as incur an energy-consuming pressure drop penalty, but for many users the dependability and familiarity of a differential pressure cell still wins out over other considerations.
Beginner's guide to differential pressure level transmitters
