Research On In-situ Calibration Technology Of Magnetostriction Liquidometer

In large capacity measurement,magnetostrictive liquid level gauge is widely used in liquid level detection of large capacity measurement process due to its high precision(up to millimeter or submillimeter),strong reliability,large measurement range(up to 30 m),high degree of automation and easy maintenance.Therefore,in the practical application,the in-situ measurement of magnetostrictive liquid level should be carried out.However,the magnetostriction liquidometer adopts the parameters of laboratory calibration in the field application,and the field application environment is very different from the experimental indoor environment.The calibration parameters are inconsistent with the field application parameters,which affects the practical application precision and reliability of the liquid level meter.In order to solve this problem,this paper studies in situ calibration technology of magnetostrictive level meter.The main research content and results are as follows:1.Based on the study of the working principle and characteristics of various liquid level meters,this paper analyzes the current status of domestic liquid level gage verification and calibration,points out the advantages and disadvantages of the existing liquid level meter verification method,puts forward the method of in situ calibration for the magnetostrictive liquid level meter,which is based on precision ranging and two-dimensional tilt measurement.The system platform and calibration process design are completed,and the system precision index allocation model is established.2.This paper presents a method for measuring the vertical degree of the liquid gauge guide rod,and the error analysis,precision evaluation and simulation experiment are carried out.A precision ranging correction model based on the prior value fitting and interpolation calculation is proposed,which solves the problem of the close range precision ranging from the phase method and provides a reference for the calibration device.Two dimensional tilt measurement technology is used to establish the model of ranging tilt and roof tilt correction,and realize the precise correction of ranging reference datum to the direction of plumb line.3.According to the requirements of the field application environment and measurement function of the calibration system,the design and development of the in-situ calibration system of the liquid-level meter was completed.The measurement precision,measurement function,measuring range and data interface of the system sub-module were analyzed,and the multisource data joint measurement,data management and reconciliation model were solved,and the measurement,calculation and report output integration of the liquid level meter in situ calibration system were realized.4.This paper analyzes the source of uncertainty component of calibration device,establishes the theory extension uncertainty evaluation model of the magnetostrictive liquid level meter in-situ calibration system,and designs the experimental scheme to verify the stability and reliability of the system,and applies the calibration device successfully to the in-situ calibration of the liquid level of a certain type of ship tank.The results show that the calibration device improves the measurement precision and efficiency,meets the requirements of the liquid level meter calibration in the large capacity measurement of the ship's cabin capacity,and realizes the unity of the level meter in-situ calibration and the traceability of the quantity value.