超声波燃气表燃气-空气关系计量特性研究

Characterization Study of Gas-Air Relationship Measurementof Ultrasonic Gas Meter

作为新型电子式计量器具,超声波燃气表具有宽量程、无机械传动结构、灵敏度高等特点。燃气表的计量特性评价一般采用空气介质。因此,空气介质和燃气介质下计量性能的一致性至关重要。采用扩展不确定度U=0.25%(k=2)的活塞式实气流量标准装置,分别对流量范围为0.04~6m~3/h和0.025~4m~3/h的1.5级超声波燃气表的燃气-空气关系性能进行试验。试验结果表明:1~#、2~#、3~#G4超声波燃气表在流量点q_(min)的燃气-空气平均误差偏移相对较大,而4~#、5~#、6~#G2.5超声波燃气表在各流量点的误差发生普遍偏移。这分别是由零点漂移和错波现象引起的。因此,在超声波燃气表的检验检测和计量性能评价试验中建议增加燃气-空气关系项目。试验结果可为国内超声波燃气表的技术研发和检定方法改进等提供重要的数据参考。

As a new type of electronic measuring instrument, ultrasonic gas meter has the characteristics of wide range, no mechanical transmission structure, high sensitivity,etc.Air medium is generally used in the evaluation of metering characteristics of gas meters.Therefore, the consistency of metering performance under air medium and gas medium is crucial.Using the extended uncertainty U =0.25% ( k =2) of the piston type real-gas flow standard device, the flow range of 0.04~6 m 3/h and 0.025 ~4 m 3/h of 1.5 grade ultrasonic gas meter gas-air relationship performance are tested respectively.The test results show that: 1 #, 2 #, 3 #G4 ultrasonic gas meter at the flow point q min gas-air average error shift is relatively large, while 4 #, 5 #, 6 # G2.5 ultrasonic gas meter in each flow point error occurred in the general shift.This is caused by zero drift and wrong wave phenomenon respectively.Therefore, it is recommended to increase the gas-air relationship project in the inspection and measurement performance evaluation test of ultrasonic gas meters.The test results can provide important data references for the technical research and development of domestic ultrasonic gas meters and the improvement of calibration methods.