热式质量燃气表计量特性试验研究

Experimental Study on Metering Characteristics of Thermal Mass Gas Meter

介绍热式质量燃气表的流量传感器工作原理,进行了初始计量特性试验、比对实验和天然气实流耐久性试验,耐久性试验时间为4 000 h。研究结果表明:经过初始计量特性试验,得知6台热式质量燃气表全部合格。经过天然气实流耐久性试验,得知参与试验的3台热式质量燃气表4 000 h耐久性试验结果全部满意。经过仪表空气比对试验,得知参与试验的3台热式质量燃气表在不同检定装置的比对结果多数为满意,仅一台燃气表一个小流量点不满意。在天然气实流耐久性试验中进行仪表的天然气实流比对,3路试验管路中安装了4台热式质量燃气表,所有试验仪表均为1.5级,其最大允许相对误差为±1.5%,误差偏差(误差偏差定义为相对误差和相应流量点的初始相对误差的差值)为±3%。每台仪表与同一管路上几台表平均气量的相对误差均未超过误差偏差(±3%),说明各试验仪表之间偏差均较为稳定,且月度偏差呈现随机现象,没有出现持续性规律性变坏趋势,在现场比对中偏差属于可以接受范围。现场实流比对试验中,东区的普通膜式表受环境温度变化影响较大,但长期平均相对误差并不大,腰轮流量计平均相对误差为正值,为2.11%,两台超声波燃气表平均相对误差为负值,分别为-0.83%和-1.65%,热式质量燃气表平均相对误差为0.05%。这表明几种表型计量特性较为稳定。

The working principle of the flow sensor of the thermal mass gas meter is introduced.The initial metering characteristic test,the comparison test and the natural gas actual flow durability test were carried out.The durability test time was 4 000 h.The research results show that after the initial metering characteristic test,it was found that all six thermal mass gas meters were qualified.After the natural gas actual flow durability test,it was found that the results of the 4 000 h durability test of the three thermal mass gas meters participating in the test were all satisfactory.After the meter air comparison test,it was found that the comparison results of the three thermal mass gas meters participating in the test in different verification devices were mostly satisfactory,and only one gas meter was not satisfied with a small flow point.In the natural gas actual flow durability test,the natural gas flow comparison of the meters was carried out.Four thermal mass gas meters were installed in the three test pipelines,all of which were 1.5 grades,the maximum allowable relative error is±1.5%,and the error deviation(the error deviation is defined as the difference between the relative error and the initial relative error of the corresponding flow point)was±3%.The relative error of the average gas volume between each meter and several meters on the same pipeline was not exceed the error deviation(±3%),indicating that the deviation between the test meters was stable,and the monthly deviation shows a random phenomenon.There was no continuous regular deterioration trend,and the deviation in the field comparison was acceptable.In the on-site actual flow comparison test,the common membrane meter in the eastern area was greatly affected by the change of ambient temperature,but the long-term average relative error was not large.The average relative error of the lumbar wheel flowmeter was positive,2.11%.The average relative errors of two ultrasonic gas meters were negative,-0.83%and-1.65%,respectively,and the average relative error of the thermal mass gas meter was 0.05%.This indicates that metering characteristics several meters are relatively stable.