No abstract

We present a novel non-invasive flow metering procedure where the flow velocity of a fluid is determined using polarized hydrogen nuclei of the fluid as magnetic markers. The metering procedure is based on a time-of-flight method in which magnetic information is applied to the liquid using a permanent magnet and a radiofrequency (RF) pulse. Downstream, the magnetic information is read-out by optically pumped magnetometers (OPM) by measuring the magnetic field produced by the hydrogen. We discuss results, application cases and challenges for industrial usability.

No abstract

We present a noninvasive procedure that measures the flow velocity of a fluid by using polarized hydrogen nuclei in the fluid. The measurement procedure is based on a time-of-flight method where magnetic information is applied on the fluid with a permanent magnet and an RF-pulse. In contrast to other methods, this magnetic-marking method works without tracers. The read-out of the magnetic information is performed by optically pumped magnetometers downstream. In order to function, the magnetometers have to be operated in a magnetic shield with magnetic field strengths lower than 100 nT, i.e., in the zero-to-ultra-low-field regime. In this regime, the magnetometers are capable of detecting induced magnetic signals of 10 pT or less with an inline-flow setup. The results presented in this paper demonstrate the viability of optically pumped magnetometers for flow metering. The first metering results yielded an average accuracy of 3% at flow velocities between 13 cm/s and 22.4 cm/s.