透气度流量盘测量方法的改进

为解决透气度流量盘测量方法因气路中的位置差异和大气压力变化对流量盘测量结果产生影响,对流量盘测量方法进行了改进。将流量盘在测量气路中的位置由在气体流量计前改为在气体流量计后,并把流量盘分为线性流量盘和非线性流量盘,计算大气压力对非线性流量盘测量结果的影响;比较了改进前后测量方法的重复性和稳定性,并采用改进后测量方法参加了CORESTA组织的流量盘共同实验。结果表明:①改进测量方法后非线性流量盘测量结果的标准偏差和变异系数以及5个月内测量结果的极差均减小了一半左右。②国内ZTRI实验室测量的流量盘流量均值与国外3家实验室测量的流量盘流量均值的相对极差都在2%以下;国内外4家实验室测量每个流量盘的流量变异系数均小于0.50%。 

Improvement of Calibration of Air Permeability Standards

Current calibration method of air permeability standards does not take into account the influences imparted by standard's position in the air circuit and atmospheric pressure variation on measurement results.Therefore,the method was improved by changing the arrangement of air permeability standard in air circuit for measurement from upstream to downstream of the flow-meter and dividing air permeability standards into two types,linear type and non-linear type.The influence of atmospheric pressure on the measurements of non-linear standards was calculated.The repeatability and stability of measuring method before and after improvement were compared,and the improved measuring method was adopted to take part in CORESTA collaborative experiments.The results showed that:1) After improvement,the standard deviation and variance coefficient of measurements,and the extreme difference of measurement results over five months for non-linear standards reduced by about 50%.2) The relative extreme difference of volumetric flow mean value of air permeability standards measured by ZTRI(Zhengzhou Tobacco Research Institute of CNTC) laboratory and three foreign laboratories were less than 2%,and the variance coefficients of measurements of each standard were all less than 0.50%.