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1.发明授权
公开(公告)号：US5734112A
公开(公告)日：1998-03-31
申请号：US689839
申请日：1996-08-14
CPC分类号： G01F15/024 , G01F1/8413 , G01F1/8431 , G01F1/8436 , G01F1/8477
摘要： A method for determining pressure in an operating Coriolis effect mass flowmeter. The Coriolis flowmeter flow tubes are vibrated in both a bending mode (as is normal for measuring mass flow rate) and in a twisting mode. The ratio of the fundamental frequencies at which the flow tubes vibrate in each of the two vibration modes is proportional to the pressure within the flow tubes. In the preferred embodiment, a sum/difference method initially isolates the superposed sinusoids representing the fundamental frequencies of the two vibrational modes. Fast conjugate gradient (FCG) digital filters are then used to rapidly estimate the fundamental frequencies in each of the two vibration modes. The estimated frequencies are then used by filter chains including digital notch and band pass filters as well as recursive maximum likelihood (RML) digital filter techniques to enhance the bending mode and twisting mode fundamental frequency estimates. The enhanced bending mode and twisting mode frequency estimates are used to determine the pressure within the flow tubes as a function of the ratio of the two frequencies as well as to center the notch and band pass filter chains used to enhance the bending mode frequency of the two vibration sensor channels for mass flow rate computations. The pressure so determined may then be used to correct mass flow rate computations or for other pressure measurement purposes per se.
摘要翻译： 用于确定操作科里奥利效应质量流量计中的压力的方法。 科里奥利流量计流量管在弯曲模式下（如测量质量流量的正常值）和扭转模式下振动。 流管在两个振动模式中的每一个振动的基频的比率与流管内的压力成比例。 在优选实施例中，和/差方法最初隔离表示两个振动模式的基频的叠加正弦曲线。 然后使用快速共轭梯度（FCG）数字滤波器来快速估计两种振动模式中的每一种的基频。 估计的频率然后由包括数字陷波和带通滤波器的滤波器链以及递归最大似然（RML）数字滤波技术用于增强弯曲模式和扭转模式基频估计。 增强的弯曲模式和扭转模式频率估计被用来确定流管内的压力作为两个频率之比的函数，以及用于增加用于增强弯曲模式频率的凹口和带通滤波器链的中心 两个用于质量流量计算的振动传感器通道。 因此，如此确定的压力可用于校正质量流量计算或其他压力测量目的本身。
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