The dynamic performance of a new ultra-fast response Coriolis flow meter

The paper identifies the requirements for both a Coriolis flow-tube and the associated flow-transmitter, to achieve an ultra-fast dynamic response. A ‘new’ meter was assembled using a commercially available straight flow-tube, selected for its high drive (fundamental resonant) frequency of about 750 Hz (water-filled) and this was interfaced with a newly extended version of Oxford’s digital transmitter technology. This new transmitter gives measurement updates that are calculated every half drive-cycle, at 1.5 kHz, and are output via a high precision frequency pulse signal. Dynamic response tests in the laboratory and during a field trial have shown the ‘new’ meter to have a response time at least an order of magnitude faster than was reported previously [Clark C, Cheesewright R. Experimental determination of the dynamic response of Coriolis mass flow meters. Flow Measurement and Instrumentation 2006;17:39–47] from tests on the fastest response commercially available Coriolis meters. The ‘new’ meter shows a typical delay of 3.8 ms between a change in fluid flow rate and the corresponding change in the frequency output. Suggested further developments of the new transmitter technology indicate a route that could be followed to produce transmitters suitable for the newly emerging micro-machined Coriolis flow-tubes, which have fundamental resonant frequencies in the range 10–30 kHz.