Synthesis of the evaluations of electromagnetic flowmeters based on vortex, Coriolis and thermal effects in the framework of SIREP-WIB-EXERA associations

Electronic flowmeters such as electromagnetic flowmeters based on vortex, mass (Coriolis) and thermal effects are being used more and more in industry (water distribution, petrochemicals, food processing). Some of them are used by EDF. A study has been therefore conducted on the main types of flowmeters which in the last years (1988-1995) were the object of an evaluation within the framework of the SIREP-WIB-EXERA users. This document synthesizes the tests conducted, and highlights the generic weaknesses linked with different methods of measurement, equipment and test methods. It meets a triple objective: 1 - up dating the EDF's knowledge on these different products; 2 -better knowledge of the diversity of problems connected with measuring flows (type and characteristics of fluids, flow ranges, environmental constraints etc.); 3 - showing the advantages and disadvantages associated with these methods and lining up different technologies with one another. As a whole from the metrological standpoint the equipment tested complies with the manufacturers' specifications. Most of this equipment highly sensitive to electromagnetic perturbations. When the European CEM directives are applied this defect should disappear. Other environmental tests do not reveal generic faults. For all the technologies evaluated it may be stated that the ranges of tests are very standardized. Unfortunately, a certain number of well thought out tests (according to the technology) are not, or rarely conducted. For instance, one can quote the vibration influence tests for vortex effect flowmeters. Advanced research has been carried out. It mainly concerns cavitation phenomena (Coriolis effect flowmeters) and the influence of viscosity and conductivity of fluids (electromagnetic and Coriolis effect flowmeters). (author)