Ultrasonic flowmeter time difference stable measurement method based on envelope threshold-peak value method

Abstract

The invention discloses an ultrasonic flowmeter time difference stable measurement method based on an envelope threshold-peak value method. The method comprises the following steps of: calculating an absolute value delta Thr of a time difference corresponding to uplink and downlink echo signal envelope thresholds and an absolute value delta Peak of a difference between uplink and downlink echo signal peaks; then judging whether the time difference is reliable or not according to the size relation between the condition |delta Peak-delta Thr| and the trigger wave shifting point number NHW, if the wave hopping phenomenon exists, conducting wave shifting according to the amplitude size judgment condition of the fourth wave before the uplink and downlink echo peak values, and eliminating the wave hopping problem. The reliability of time difference measurement can be judged. When the time difference measurement is not reliable, a real time difference measurement value can be obtained through wave shifting processing; according to the method, the problem that wave hopping occurs under the condition that ultrasonic echo signal characteristics are affected to a certain degree under the complex and unstable working conditions such as airflow instability, different pressures and site vibration can be solved, and therefore the stability and reliability of the flowmeter in the metering application occasion are guaranteed.

Description

technical field [0001] The invention belongs to a flow measurement method in the field of measurement technology, in particular to a time difference stable measurement method of an ultrasonic flowmeter based on an envelope threshold-peak method. Background technique [0002] Compared with other instruments, ultrasonic flowmeters have obvious advantages in accuracy, repeatability, turndown ratio, reliability, stability, pressure loss, daily maintenance, etc., and have been widely used in trade measurement applications. Ultrasonic flowmeters have been used as the main custody transfer measurement instruments in pipelines and other occasions. [0003] At present, most ultrasonic measurement products are only suitable for normal pressure environments, and cannot adapt to high-pressure applications. In high-pressure environments, changes in pipeline pressure and gas flow will cause changes in the waveform characteristics of ultrasonic echo signals, resulting in periodic jumps or ...

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Problems solved by technology

[0004] In order to overcome the above-mentioned shortcoming of prior art, the object of the present invention is to provide a kind of ultrasonic flowmeter time difference stable measurement method based on envelope threshold-peak value method, can judge the reliability of time difference measurement, when time difference measurement is unreliable, Through wave shifting processing, the real time difference measurement value can be obtained; the present invention can solve the problem that occurs under complex and unstable working conditions, such as unstable air flow, different pressures, field vibrations, etc., which have a certain influence on the characteristics of ultrasonic echo signals. The problem of wave jumping, so as to ensure the stability and reliability of the flowmeter in metering applications

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