| 摘要 |
Acoustic flow meters are used for the measurement of flow velocity of fluids . They have particular application in meters for gas and water in pipelines. T he meter includes a tube fitted with three or more acoustic transducers distributed along its length and arranged to transmit wave packets up and do wn between at least two pairs of the acoustic transducers. The wave packets comprise a signal including zero crossings spaced apart by a packet period determined by a known packet frequency. The flow meter also includes measurement means associated with the transducers to make first measurements of received packets, from which the time of arrival of the zero crossings of a received packet can be determined relative to the time of transmission of th e packet. A second measurement from which a particular zero crossing in the transmitted packet can be identified in the received packet. And calculation means to determine the velocity of fluid flow in the tube using the measurements. There is also a method of operation.
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