便携无损式超声波流量测试系统设计与验证

Design and Application of Portable Nondestructive Ultrasonic Flow Test System

摘要:

针对传统液体流量计传感器会对管路造成损坏或阻碍液体流动、操作安装较为复杂的问题,设计了一种基于时差法的便携无损式超声波流量测试系统,采用外夹式超声波探头形式,无需破坏管路系统即可实现液体流量的精确测量。本系统采用粗时间与细时间测量相结合的测量算法设计了一种基于延迟线内插法的FPGA高速率、高精度时间测量算法电路,最高可实现1050 Hz的测量速率；设计了信号调理校准电路,具备较强的正负增益可调性以及高信噪比输出能力,增益可调范围达到-23.5 dB ~ +116.5 dB；还设计了多种传感器专用安装导轨以确保其安装精度。最后,在计量实验室进行了验证测试,结果表明所设计的测试系统符合JJG1030-2007规范准确度0.5级的技术要求,准确度低于±0.5%,重复性低于0.1%。

Abstract:

Aiming at the problems that the traditional liquid flowmeter sensor will damage the pipeline or hinder the flow of liquid, and the operation and installation are more complicated, a portable non-destructive ultrasonic flow test system based on the time difference method is designed. The system adopts the form of external clamped ultrasonic probe, which can realize the accurate measurement of liquid flow without destroying the pipeline system. This system uses a measurement algorithm that combines coarse time and fine time measurement, and designs a FPGA high-speed, high-precision time measurement algorithm circuit based on delay line interpolation, which can achieve a measurement rate of up to 1050 Hz. A signal conditioning and calibration circuit is also designed, which has strong positive and negative gain adjustability and high signal-to-noise ratio output capability. The gain adjustable range is -23.5 dB ~ +116.5 dB. A variety of special mounting rails for sensors are also designed to ensure its installation accuracy. Finally, a verification test was carried out in the metrology laboratory, and the result showed that the designed test system meets the technical requirements of JJG1030-2007 with an accuracy of 0.5 level. The accuracy is less than ±0.5%, and the repeatability is less than 0.1%.