| 摘要 |
A measuring system for measuring a density of a medium flowing in a process line along a flow axis of the measuring system in the case of a medium which is variable as regards a thermodynamic state, especially a medium which is, at least in part, compressible. Included are: at least one temperature sensor placed at a temperature measuring point, reacting primarily to a local temperature, theta, of medium flowing past, and delivering at least one temperature measurement signal influenced by the local temperature of the medium to be measured; at least one pressure sensor placed at a pressure measuring point, reacting primarily to a local, especially a static, pressure, p, of medium flowing past, and delivering at least one pressure measurement signal influenced by the local pressure, p, in the medium to be measured; as well as a measuring electronics communicating, in each case, at least at times, with the temperature sensor and the pressure sensor. The measuring electronics ascertains, with application both of the temperature measurement signal as well as also at least the pressure measurement signal, a provisional density measured value, which represents a density, which the flowing medium only apparently has at a virtual density measuring point, especially a virtual density measuring point predeterminably spaced from the pressure measuring point and/or the temperature measuring point along the flow axis. Additionally, the measuring electronics produces, with application of the provisional density measured value as well as at least density correction value determined at run-time and dependent both on a flow velocity of the medium as well as also on the local temperature reigning at the temperature measuring point, at least at times, at least one density measured value, especially a digital density measured value, differing from the provisional density measured value and instantaneously more accurately representing than the provisional density measured value a local density, rho, which the flowing medium actually has at the virtual density measuring point.
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