| 摘要 |
<p>The mass flow rate in a pipeline (1) is measured via two pressure monitors (7, 8) either side of a constriction (2) in the pipeline (1). The flow rate is sinusoidally modulated, soft hat the pressure difference between the monitors (7, 8) fluctuates. This fluctuating pressure difference is divided by a value proportional to the rate of modulation and the mean value obtained, to eliminate harmonic components. Pref. the modulation is provided by an electromechanical transducer (3) coupled to an oscillator (4). This transducer (3) may comprise a piezoelectric ring positioned in front of the constriction (2).</p> |
