基于激光跟踪仪的超声流量计几何参数实测方法

Geometric Parameter Measurement of Ultrasonic Flowmeter Based on Laser Tracker

针对需要现场安装的大口径超声流量计的几何参数外部测量问题,建立了基于激光跟踪仪的大口径超声流量计几何参数测量方法。利用跟踪仪在管道外部测量管段壁面和超声探头的三维特征,并通过三维建模工具获得管段和探头的相对位置关系,进而计算得到流量计几何参数。结合现场测量案例,评估了内径、声道长度、声道角、声道高度等参数对流量不确定度的贡献。该方法不仅解决了管道外部几何参数实测问题,而且能将不确定度水平控制在0.2%左右。与跟踪仪实测值相比,几何参数厂家设置值存在一定的差异,建议厂家和用户给予几何参数实测更多的关注。

For large diameter ultrasonic flowmeters with probes installed on existing pipe,geometric parameters measurement contribute a lot to the flowmeter accuracy,based on laser tracker,a geometrical parameter measurement method for large-diameter ultrasonic flowmeter is established.3-D coordinates of pipe surface points and probe cylinder points are collected by laser tracker outside the pipe.Spatial model of the pipe and probes are built by a commercial tool,and then all the geometric parameters are calculated.Two field measurements of pump station pipes are performed to estimate the flow uncertainty due to different geometric parameters using this method.The method not only solves the problem of geometric measurement outside the pipe,and the uncertainty level is also controlled at around 0.2%.Compared with the measured values by the laser tracker,it is show that there are not small deviation in the setting values by manufacturers,which needs to be paid more attention by manufacturers and owners.