GB/T 5275.6-2023Gas analysis - Preparation of calibration gas mixtures using dynamic methods - Part 6: Critical flow orifices (English PDF)

foreword

This document is in accordance with the provisions of GB/T 1:1-2020 "Guidelines for Standardization Work Part 1: Structure and Drafting Rules for Standardization Documents"

drafting:

This document is part 6 of GB/T 5275 "Preparation of Calibration Mixed Gases by Dynamic Volumetric Method for Gas Analysis": GB/T 5275 has

The following parts have been published:

--- Part 1: Calibration method;

--- Part 2: Piston pumps;

--- Part 4: Continuous injection method;

--- Part 5: Capillary calibrator;

--- Part 6: Critical flow orifices;

--- Part 7: Thermal mass flow controllers;

--- Part 8: Diffusion method;

--- Part 9: Saturation method;

--- Part 10: Infiltration method;

--- Part 11: Electrochemical generation method:

This document replaces GB/T 5275:6-2014 "Preparation of mixed gases for calibration by dynamic volumetric method for gas analysis - Part 6: Critical sharpness

Compared with GB/T 5275:6-2014, except for structural adjustment and editorial changes, the main technical changes are as follows:

--- Added a chapter on terms and definitions (see Chapter 3);

--- A chapter on symbols has been added (see Chapter 4);

--- Changed the content related to the principle and equipment (see Chapter 5, Chapter 3 and Chapter 4 of the:2014 edition);

---Changed the calculation of mass flow and volume flow (see Chapter 6, 5:1, 5:3 of the:2014 edition);

---Changed the amount fraction and volume fraction of the calculated substance and related uncertainty assessment (see Chapter 7, 5:4 of the:2014 edition);

--- Changed the application of preparation of mixed gases (see Chapter 8, Chapter 4 of the:2014 edition);

--- Increased calibration and verification (see Chapter 9):

This document identically adopts ISO 6145-6:2017 "Preparation of mixed gas for calibration by dynamic method of gas analysis - Part 6: Critical flow sharpness

hole":

The following minimal editorial changes have been made to this document:

--- For the errata of ISO 6145-6:2017, the editorial changes made to the "References" and their reasons are shown in Appendix NA:

Please note that some contents of this document may refer to patents: The issuing agency of this document assumes no responsibility for identifying patents:

Introduction

The dynamic method is an important method for preparing mixed gases for calibration, and ISO has specially compiled the ISO 6145 series of standards for this purpose:

(ISO 6145-3 air flow intermittent injection method has been abolished):

GB/T 5275 (all parts) are equivalent to ISO 6145 series standards: Due to the length of the text, ISO 6145 is divided into 11 parts

points, GB/T 5275 is consistent with ISO 6145, and is also divided into 11 parts correspondingly: Since ISO 6145-3 has been abolished, GB/T 5275 No:

3 parts are also correspondingly vacant: GB/T 5275 (all parts) specifies the general requirements for the preparation of mixed gases for calibration by the dynamic method, and specifically

It specifies the principles, main equipment, preparation precautions, and prepared calibration gas mixtures of nine methods such as volumetric pump method:

The technical requirements for the calculation of the volume fraction of the mixed gas components and the evaluation of the uncertainty are to ensure the quality of the prepared mixed gas for calibration and improve the quality of the mixed gas:

High level of preparation of calibration gas mixtures:

GB/T 5275 (all parts) is intended for use by trained professionals with practical experience:

GB/T 5275 consists of 10 parts:

--- Part 1: Calibration method: It stipulates the basic information and applicability of each preparation method, precautions for operating the dynamic system, dynamic

The calibration method of the system, the calculation of components and uncertainty, and the verification method are the basis of the other 9 parts: purpose is

Provide a reasonable selection of one or more methods of preparing mixed gases for calibration and link these methods to national measurement standards

To establish the measurement traceability of the composition of the prepared mixed gas:

--- Part 2: Piston pumps: The purpose is to provide calibration equipment prepared from two or more pure gases or other mixed gases using a piston pump:

The method of mixed gas, and the calculation method and uncertainty evaluation of the content of each component in the prepared mixed gas for calibration

Way:

--- Part 4: Continuous injection method: The purpose is to provide continuous injection of pure gas or other mixed gas into the balance gas through the syringe:

A method for continuously preparing a calibration mixed gas containing two or more components, and the prepared calibration mixed gas

Calculation method and uncertainty evaluation method of the content of each component in the compound gas:

--- Part 5: Capillary calibrator: The purpose is to provide the use of equipment containing single or multiple capillary combinations from pure gases or

Method for continuously preparing mixed gas for calibration with mixed gas, and calculation of the content of each component in the prepared mixed gas for calibration

method and uncertainty assessment method:

--- Part 6: Critical flow orifice: The purpose is to provide the use of critical flow orifice by two or more pure gas or other used gas

A method for preparing a mixed gas for calibration by mixing, and a calculation method for the content of each component in the prepared mixed gas for calibration, and

Uncertainty assessment method:

--- Part 7: Thermal mass flow controllers: The purpose is to provide the use of thermal mass flow controllers connected by pure gas or mixed gas

The method for preparing the mixed gas for calibration, the calculation method of the content of each component in the prepared mixed gas for calibration and the different

Certainty assessment method:

--- Part 8: Diffusion method: The purpose is to provide a mixture of two or more pure gases or other used gases using the diffusion method

The method of preparing the mixed gas for calibration, and the calculation method of the content of each component in the prepared mixed gas for calibration and the uncertainty

Quantitative assessment method:

--- Part 9: Saturation method: The purpose is to provide a method for the continuous preparation of calibration mixtures from one or more easily condensable gases using the saturation method:

The method of mixing gas, and the calculation method and uncertainty evaluation method of the content of each component in the prepared calibration mixed gas:

--- Part 10: Infiltration method: The purpose is to provide continuous preparation of mixed gas for calibration from pure gas or mixed gas using permeation method

method, and the calculation method of the content of each component in the prepared calibration mixed gas and the method of uncertainty assessment:

--- Part 11: Electrochemical generation method: The purpose is to provide a continuous preparation calibration method from pure gas or mixed gas using electrochemical generation method:

The method of using the mixed gas, and the calculation method of the content of each component in the prepared mixed gas for calibration and the uncertainty evaluation

set the way:

Preparation of mixed gas for calibration by dynamic method of gas analysis

Part 6: Critical flow orifice

1 Scope

This document specifies a method for the dynamic preparation of calibration gas mixtures using a critical flow orifice system: Calibration mixed gas consists of at least

Two gases (one of which is usually make-up gas) either pure or premixed:

The method specified in this document is mainly applicable to the preparation of gas pipeline materials that do not react with critical flow orifice systems or auxiliary equipment:

mixed composition: When an appropriate number of critical flow orifices are used, multi-component gas mixtures can be prepared:

The dilution ratio can reach 1x104 by choosing a suitable critical flow orifice combination:

Although the methods specified in this document are generally applied to the preparation of gas mixtures under atmospheric pressure conditions, the methods specified in this document can also be used

Preparation of calibration gas mixture at a pressure exceeding atmospheric pressure: Using the method specified in this document, the upstream gas pressure needs to be at least higher than the downstream gas pressure:

twice as high:

The applicable flow range of this document is 1mL/min~10L/min:

2 Normative references

The contents of the following documents constitute the essential provisions of this document through normative references in the text: Among them, dated references

For documents, only the version corresponding to the date is applicable to this document; for undated reference documents, the latest version (including all amendments) is applicable to

this document:

ISO 6143 Comparison method for the determination and verification of gas analysis calibration gas mixture composition (Gasanalysis-Comparison

Note: GB/T 10628-2008 Determination and verification comparison method of gas analysis calibration mixture gas composition (ISO 6143:2001, IDT)

ISO 7504 Gas Analysis Vocabulary (Gasanalysis-Vocabulary)

Note: GB/T 14850-2020 Gas Analysis Vocabulary (ISO 7504:2015, IDT)

Venturinozzles)

Note: GB/T 21188-2007 measures gas flow with a critical flow Venturi nozzle (ISO 9300:2005, IDT)

ISO 12963 Gas analysis, comparative method for determination of gas mixture composition based on one-point and two-point calibration (Gasanalysis-

pointcalibration)

ISO 16664 Guidelines for the use of pure and mixed gases for gas analysis calibration (Gasanalysis-Handlingofcalibra-

Note: GB/T 37180-2018 Guidelines for the use of pure gas and mixed gas for gas analysis calibration (ISO 16664:2017, IDT)

3 Terms and Definitions

The terms and definitions defined in ISO 9300, ISO 7504 and the following apply to this document:

3:1

criticalflow orifice criticalfloworifice

Orifice whose geometry and conditions of use allow the throat flow to reach the critical flow (3:12)