The Study Of In-site Calibration System For Large Range Level Gauge

Level gauge which has a range more than 2m and mianly is used on oil measurement is known as large range level gauge.Traditional large range level guage calibration methods include manual calibration and comparison method.The accuracy of mannul calibration is not good enough and by comparison method you must send the level to specific institution for calibration.Two methods are proposed for large range level gauge in-site calibration in this research.One is used on guege calibration of empty tank and the other for online calibration.The main research contents are as follows:(1)After learning various level gauge calibration methods,two in-site calibration methods are proposed in this paper based on the conditions of the oil depots.The first one is that by using telescopic rod and reflecting plate to simulate the change of liquid level in the empty tank in order to calibration the level gauge seted on the top of the tank.The other method is an online calibration method with the help of a plump,float and standard device.(2)The hardware platform of the field calibration system of the large range liquid level gauge and the corresponding software are built.A three-point laser range finder is designed to be used as a standard device for calibrating liquid level gauge,and its indication is corrected by artificial neural network.The maximum error after correction is <2 mm.(3)To validate whether the system can achieve expected resule,test the system in the lab and in-site.Two kinds of standard devices are used separately in the experiments.Then,compare the calibration results to validate the precision of the standard device especially the three-point laser range finder.Finally,analy the errors and uncertainty for the system.