GB/T 5275.6-2014
Gas analysis.Preparation of calibration gas mixtures using dynamic volumetric methods.Part 6:Gritical orifices (English Version)

Standard No.

GB/T 5275.6-2014

Language

Chinese, Available in English version

Release Date

2014

Published By

General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China

Status

Be replaced 2023-10

Replace By

GB/T 5275.6-2023

Latest

GB/T 5275.6-2023

Scope

This part of GB/T 5275 specifies the method for continuously preparing a calibration mixed gas of two or more components with pure gas or mixed gas through a critical orifice system. By selecting a suitable combination of orifices and using pure gas, the volume fraction of the calibration components in the calibration mixture can be changed by a factor of 10⁴. In addition, by changing the initial pressure of the orifice system, the volume fraction of the calibration components can be changed by a factor of 10². The uncertainty of the critical orifice method depends primarily on the flow calibration method, temperature variation, and outlet pressure. The relative expanded uncertainty (when the coverage factor k=2) of the available volume fraction of the binary gas mixture is 3%. Gas mixtures with much lower volume fractions can be prepared using premixed gases rather than pure gases (see Appendix A). Determine the mass flow or volume flow of the mass or volume fraction, which can be calculated or measured separately using an appropriate method given in ISO 6145-1. The advantage of this preparation method is that a large amount of mixed gas can be prepared continuously, and as long as an appropriate number of orifices are used, the preparation of multi-component mixed gas is as easy as the preparation of binary mixed gas. Flow rates can range from a few milliliters per minute to 10 L per minute. This method is especially suitable for preparing mixed gas under atmospheric pressure, but it can also be prepared under pressure higher than atmospheric pressure. Practical hints for using this method can be found in Appendix B.

GB/T 5275.6-2014 Referenced Document

• GB/T 10628-2008 Gas analysis.Comparison methods for determining and checking the composition of calibration gas mixtures
• GB/T 5275.1-2014 Gas analysis.Preparation of calibration gas mixtures using dynamic volumetric methods.Part 1:Methods of calibration

GB/T 5275.6-2014 history

• 2023 GB/T 5275.6-2023 Preparation of gas mixtures for calibration by dynamic method of gas analysis - Part 6: Critical flow orifice
• 2014 GB/T 5275.6-2014 Gas analysis.Preparation of calibration gas mixtures using dynamic volumetric methods.Part 6:Gritical orifices

GB/T 5275.6-2014 -All Parts