LNG加气机现场检定方法的研究

A comparative analysis of field calibration methods for LNG dispensers

LNG加气机作为一种尚处于发展阶段的新的计量器具,其现场检定较为困难。为此,介绍了LNG的物理特性和计量难点,剖析了LNG加气机的结构和工作流程,对比分析了称重法和标准表法(又分为启停法和动态法)的优缺点和现场可操作性。实验数据表明,采用标准表法(尤其是动态检定法)对LNG加气机进行现场检定更为合理可行。在此基础上研制了一套实用的标准表法LNG加气机现场检定装置,该装置测量结果可靠,现场可操作性强,符合LNG加气机的现场检定校准要求。

An LNG dispenser is a new tool for refueling the vehicles with a metering system but it is rather difficult to calibrate its accuracy level at an LNG refueling station.In view of this,this paper introduces the physical characteristics and metering difficulties of LNG and analyzes the structures and working procedures of an LNG dispenser.Its metering accuracy level can be calibrated by the weighting and master metering methods,the latter of which is divided into the start-stop method and the dynamic method.A comparative analysis of the above methods is made in terms of their advantages,disadvantages,and field operability.From experimental data,the master metering method,especially the dynamic one,is much more feasible for the calibration of LNG dispensers at the refueling stations.