The FLUXUS range of non-invasive ultrasonic gas, steam and liquid flow meters measure according to ultrasonic measurement principles:
- Transit-Time Difference Principle
- Correlation Flow Measurement principle
Transit-Time Difference Principle
This method exploits the fact that the transmission speed of an ultrasonic signal depends on the flow velocity of the carrier medium. Similarly to a swimmer swimming against the current, an ultrasonic signal moves slower against the flow direction of the medium than when travelling with flow direction.
For the measurement, two ultrasonic pulses are sent through the medium, one in the flow direction, and a second one against it. To accomplish this, Each transducer is alternately working as an emitter and a receiver. The transit-time of the ultrasonic signal propagating with the flow direction is shorter than the transit-time of the signal propagating against the flow direction.
A transit-time difference, Δt, can thus be measured which allows the determination of the average flow velocity based on the propagation path of the ultrasonic signals. A profile correction is performed by our proprietary algorithms, to obtain exceptional accuracy of the average flow velocity on the cross-section of the pipe-- which is proportional to volume flow rate.For given fluids, mass flow can even be reported when temperature and pressure are known . If entrained solids orgassesexceedabout 10% of the total volume flow, FLUXUS automatically switches to its built-in HybridTrek mode, ensuring accurate and reliable measurement even in such challenging conditions.
Since ultrasounds propagate through solids, the transducers can be mounted on the pipe surface. The measurement is therefore non-invasive, and no cutting or welding of pipes is thus required for their installation.
PIOX - Process Analytics via Ultrasound or Refractometry
In the case of the PIOX-S FLEXIM's range of PIOX process analyzers also work non-invasively by ultrasound. In addition to the measurement of the transit time difference, PIOX S also determines the fluid’s sonic velocity, which is correlated to its concentration and density.
In contrast, the Process Refractometer PIOX R works according to a completely different measurement method: The patented transmitted light measurement principle.
Here, the refractometer measures the refraction of a light beam that is transmitted through the medium. The angle of refraction strictly correlates to the medium’s concentration. In comparison to conventional process refractometers, most of which work according to the critical angle principle, PIOX R is completely unaffected by measurement drift caused by deposits on the prism.