A review of the liquid helium flow rate measurement techniques at some operating facilities with superconducting magnets

Within the ITER Project activities an LHe flowmeter will be designed to pro vide numerous long-term measurements under post-thermalcyclink, quench and other operational conditions. The device should serve both for operational monitoring and back-up quench detecting. A long distance between an interna l measuring device and a feedthrough requires the use of external sensors w ith low voltage feedthrough rather than helium capillaries. A range of the most popular methods of measuring a liquid helium how is discussed. The res ults of the flow measurements on the facilities T-15, PTF, DPC, TOSKA, CSMC , ENEA (PUFF) are described. Different types of measuring devices are consi dered, including the Venturi tube, diaphragm, turbine, Coriolis, V-Cone, ul trasonic and correlation flowmeters.