The Research On Flow Remote Calibration And Calibrator In The Sewage Pipe Network

In recent years,the requirements of the sewage flow measurement are more and more rigorous.In order to ensure the accuracy of sewage flow measurement,the accuracy and reliability of field electromagnetic flowmeter have to be ensured.So we need to calibrate the electromagnetic flowmeter.This paper is aimed to a variety of disadvantages of the existing methods of electromagnetic flowmeter calibration in the sewage pipe network,and combined with remote calibration technology,a new method of field electromagnetic flowmeter calibration is sought,which makes the process of calibration become more convenient and more reliable.This issue is mainly studied from the following three aspects:(1)Optimization of the field calibratorThis paper still uses a comparison method of a standard meter as a method of field calibration in the sewage pipe network,but abandons the traditional portable ultrasonic flowmeter to act as calibrator.Optimization it based on the existing insertion electromagnetic flowmeter and according to the calibration’s requirements,design a insertion electromagnetic flowmeter with the accuracy of at least 0.7 level as a calibrator with 2.0 level pipeline type electromagnetic flowmeter.Through analysis,it is determined that the linearity of the insertion type electromagnetic flow sensor is optimized.Firstly,according to the flow field distribution after the probe was inserted into the pipe,analyzing the main factor to affect the linearity of the probe.Then CFD software is used to establish the mathematical model of the flow field distribution and carry out numerical simulation.Finally,the optimal probe model is determined.Besides,the insertion type electromagnetic flowmeter is manufactured and the experimental verification is carried out,so as to verify the feasibility of improving the accuracy of the insertion type electromagnetic flowmeter by optimizing it’s linearity.(2)A integral design and realization of field electromagnetic flowmeter with remote calibration system in the sewage pipe networkThis remote calibration system includes the collection of field detected meter and calibrator’s flow data,the construction of the PC platform and the transmission of the data.Selecting the reasonable remote transmission mode is the basis of ensuring the realization of the remote calibration system.And it should ensure that the man-machine interface of PC platform is friendly,which can directly display the indispensable information.(3)Evaluation of uncertainty of remote calibration system of field electromagnetic flowmeter in the sewage pipe networkAnalyze the sources of uncertainty of the whole remote calibration system,evaluate the system uncertainty,evaluate the system performance,and judge the reliability of the calibration system.