Compensating for frequency change in flowmeters

摘要

Motion is induced in a conduit that contains a fluid. The motion is induced such that the conduit oscillates in a first mode of vibration and a second mode of vibration. The first mode of vibration has a corresponding first frequency of vibration and the second mode of vibration has a corresponding second frequency of vibration. At least one of the first frequency of vibration or the second frequency of vibration is determined. A phase difference between the motion of the conduit at a first point of the conduit and the motion of the conduit at a second point of the conduit is determined. A quantity based on the phase difference and the determined frequency is determined. The quantity includes a ratio between the first frequency during a zero-flow condition and the second frequency during the zero-flow condition. A property of the fluid is determined based on the quantity.

主权项

1. A method comprising:
inducing motion in a flowtube containing a fluid such that the flowtube oscillates in a first bending mode of vibration and a second bending mode of vibration, the first bending mode of vibration having a corresponding frequency of vibration and the second bending mode of vibration having a corresponding frequency of vibration; determining the first frequency of vibration; determining the second frequency of vibration; and determining a property of said fluid in the flowtube using the determined first and second frequencies and a ratio between the first and second frequencies.