| 摘要 |
The device has a measurement tube (8) with a sound transmitter (1) to emit sound waves up and downstream in the tube and two acousto-electric sensors (3,4) axially spaced from the transmitter up and downstream. The transmitter and sensors are powered with different variable frequencies. Mixer and filter units separately generate and select the difference between the frequencies for each sensor. An analyzer measures the phase or time difference. The device has a measurement tube (8) with at least one sound transmitter (1) which emits sound waves both upstream and downstream in the tube and two acousto-electric sensors (3,4) axially spaced from the transmitter upstream and downstream. The transmitter is fed by a first transmitter with a first variable frequency. The acoustic sensors are powered by a second transmitter with a second variable frequency. Mixer and filter units separately generate and select the difference between the first and second frequencies for each sensor. A control unit sets the frequencies. An analyzer picks up the mixed and selected differential signals of both measurement channels, measures the phase or time difference relative to a reference and, on the basis of this, determines the flow speed and volume flow rate. Independent claims also cover a method of measuring flow.
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