标准摘要
[中文适用范围]： 本部分ISO 6145是处理用于制备校准气体混合物的各种动态体积法的一系列国际标准之一。本部分规定了一种连续制备含有一种或多种易冷凝组分的校准气体混合物的方法。使用此方法，通过乘以覆盖因子k=2获得的相对扩展测量不确定度U，不大于±1%。与ISO 6145其他部分介绍的方法不同，本部分描述的方法不需要准确测量流量，因为流量不出现在计算体积分的方程中。易冷凝气体和蒸气通常吸附在表面上，因此很难通过静态方法制备含有此类组分的组成准确的稳定校准气体混合物。此外，如果压力接近饱和极限，这些校准气体混合物无法维持而不发生冷凝。饱和法可用于制备此类混合物。 [外文原描述]： ISO 6145-9:2009 is one of a series of International Standards dealing with various dynamic volumetric methods used for the preparation of calibration gas mixtures. This part specifies a method for continuous production of calibration gas mixtures containing one or more readily condensable components. A relative expanded uncertainty of measurement, U , obtained by multiplying the relative combined standard uncertainty by a coverage factor k = 2, of not greater than ±1 %, can be obtained using this method. Unlike the methods presented in the other parts of ISO 6145, the method described in this part does not require accurate measurement of flow rates since flow rates do not appear in the equations for calculation of the volume fraction. Readily condensable gases and vapours commonly become adsorbed on surfaces, and it is therefore difficult to prepare stable calibration gas mixtures of accurately known composition, containing such components, by means of static methods. In addition, these calibration gas mixtures cannot be maintained under a pressure near the saturation limit without the occurrence of condensation. The saturation method can be employed to prepare mixtures of this type.
英文名称Gas analysis — Preparation of calibration gas mixtures using dynamic volumetric methods — Part 9: Saturation method