| 摘要 |
A flow measuring arrangement for measuring flow of a medium through a measuring tube, including: at least one constriction located in the measuring tube, which effects a reduction of a volume through which the medium flows internally in the measuring tube, and therewith a change in pressure conditions internally in the measuring tube, dependent on dimensions of the constriction and dependent on flow. A measuring system connected to the measuring tube which serves to measure a pressure (&Dgr;p, p) dependent on flow through the measuring tube and dependent on the dimensions of the constriction. Measuring electronics, which determines flow on the basis of the measured pressure (&Dgr;p, p). The flow measuring arrangement can, with minimal degradation of flow through the measuring tube, perform an automatic monitoring of its functional ability. To this end, the flow measuring arrangement additionally includes: at least one deflectable membrane applied to one of the measuring tube constrictions internally in the measuring tube, wherein deflection of the membrane effects a change, dependent on an amplitude of the deflection, of a volume through which medium flows internally in the measuring tube; an apparatus (23) for producing a time variable deflection of the membrane according to a predetermined time-dependent deflection profile; and, connected to the apparatus and to the pressure measuring system, a diagnostic system, which determines at least one effect of time-dependent changes of deflection of the membrane on the measured pressure (&Dgr;p, p), and which produces a diagnosis of the functional ability of the flow measuring arrangement based on the predetermined time-dependent deflection profile and effects, as determined by the diagnostic system, of associated time-dependent changes of the deflection of the membrane on the measured pressure (&Dgr;p, p).
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