1、BRITISH STANDARD BS EN ISO 6145-1:2008 Gas analysis Preparation of calibration gas mixtures using dynamic volumetric methods Part 1: Methods of calibration ICS 71.040.20 BS EN ISO 6145-1:2008 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 11
2、 October 2004 ISBN 978 0 580 60358 7 National foreword This British Standard is the UK implementation of EN ISO 6145-1:2008. It is withdrawn. The UK participation in its preparation was entrusted to Technical Committee PTI/15, Natural gas and gas analysis. A list of organizations represented on this
3、 committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Amendments/corrigenda
4、issued since publication Date Comments This corrigendum renumbers BS ISO 6145-1:2003 as BS EN ISO 6145-1:2008 28 February 2009 BSI 2009 30 identical with ISO 6145-1:2003. It supersedes BS ISO 6145-1:2003 which is EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 6145-1 August 2008 ICS 71.040.
5、40 English Version Gas analysis - Preparation of calibration gas mixtures using dynamic volumetric methods - Part 1: Methods of calibration (ISO 6145-1:2003) Analyse des gaz - Prparation des mlanges de gaz pour talonnage laide de mthodes volumtriques dynamiques - Partie 1: Mthodes dtalonnage (ISO 61
6、45- 1:2003) Gasanalyse - Herstellung von Kalibriergasgemischen mit Hilfe von dynamisch-volumetrischen Verfahren - Teil 1: Kalibrierverfahren (ISO 6145-1:2003) This European Standard was approved by CEN on 30 July 2008. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which s
7、tipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN member. This European Stand
8、ard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions. CEN members are the national sta
9、ndards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United K
10、ingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 6145-1:200
11、8: EForeword The text of ISO 6145-1:2003 has been prepared by Technical Committee ISO/TC 158 “Analysis of gases” of the International Organization for Standardization (ISO) and has been taken over as EN ISO 6145-1:2008 by Technical Committee CEN/SS N21 “Gaseous fuels and combustible gas” the secreta
12、riat of which is held by CMC. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by February 2009, and conflicting national standards shall be withdrawn at the latest by February 2009. Attention is draw
13、n to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the followin
14、g countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Sloveni
15、a, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 6145-1:2003 has been approved by CEN as a EN ISO 6145-1:2008 without any modification. BSENISO61451:2008 iiiContents Page Introduction v 1 Scope 1 2 Normative references . 1 3 Terms and definitions. 1 4 Calibrat
16、ion methods . 2 4.1 General. 2 4.2 Description of primary or potentially primary measuring devices 4 4.3 Measurements on the final mixture. 12 5 Techniques for preparation of gas mixtures calibrated by the methods described in Clause 4 13 5.1 General. 13 5.2 Volumetric pumps (see ISO 6145-2 3 ) 15 5
17、.3 Continuous injection (see ISO 6145-4 4 ) 15 5.4 Capillary (see ISO 6145-5 5 ). 15 5.5 Critical orifices (see ISO 6145-6 6 ) 16 5.6 Thermal mass flow controllers (see ISO 6145-7 7 ) 16 5.7 Diffusion (see ISO 6145-8 8 ) 16 5.8 Saturation (see ISO 6145-9 9 ) 17 5.9 Permeation (see ISO 6145-10 10 ).
18、17 Annex A (normative) Volume measurement by weighing the water content. 19 Annex B (informative) Description of secondary devices which need calibration against primary devices . 23 Bibliography . 32 BSENISO61451:2008blank I SO 3002 All irhgts seredevr vIntroduction This part of ISO 6145 is one of
19、a series of standards which describes the various dynamic volumetric methods used for the preparation of calibration gas mixtures. In dynamic volumetric methods a gas, A, is introduced at volume or mass flow rate q Ainto a constant flow rate q Bof a complementary gas B. Gas A can be either a pure ca
20、libration component, i, or a mixture of i in A. The volume fraction, i,Mof i in the final calibration gas mixture is given in the following equation: A ,M ,A AB ii q qq = + where i,Ais the volume or mass fraction of component, i, in the pre-mixed gas A, and is already known from its method of prepar
21、ation. It is assumed that in this equation, i,B , the concentration of component, i, in gas B, is zero. The introduction of gas A can be continuous (e.g. permeation tube) or pseudo-continuous (e.g. volumetric pump). A mixing chamber should be inserted in the system before the analyser and is particu
22、larly essential in the case of pseudo-continuous introduction. The flow rate of component A is measured either directly in terms of volume or mass, or indirectly by measuring the variation of a physical property. The dynamic volumetric preparation techniques produce a continuous flow rate of calibra
23、tion gas mixtures into the analyser but do not generally allow the build-up of a reserve by storage under pressure. The main techniques used for the preparation of the mixtures are: a) volumetric pumps; b) continuous injection; c) capillary; d) critical orifices; e) thermal mass-flow controllers; f)
24、 diffusion; g) saturation; h) permeation; i) electrochemical generation. In all cases, and most particularly if very dilute mixtures are concerned, the materials used for the apparatus are chosen as a function of their resistance to corrosion and low absorption capacity (usually glass, PTFE or stain
25、less steel). It should, however, be pointed out that the phenomena are less important for dynamic volumetric methods than for static methods. Numerous variants or combinations of the main techniques can be considered and mixtures of several constituents can also be prepared by successive operations.
26、 BSENISO61451:2008IS-5416 O1:(3002E) vi I SO 3002 All irhgts seredevrSome of these techniques allow calculation of the final concentration of the gas mixture from basic physical information (e.g. mass rates of diffusion, flow through capillaries). However, since all techniques are dynamic and rely o
27、n stable flow rates, this part of ISO 6145 emphasizes calibration of the techniques by measurement of the individual flow rates or their ratios, or by determination of the composition of the final mixture. The uncertainty of the composition of the calibration gas mixture is best determined by compar
28、ison with a gas mixture traceable to international standards. Certain of the techniques which may be used to prepare a range of calibration gas mixtures may require several such traceable gas mixtures to verify their performance over that range. The dynamic volumetric technique used has a level of u
29、ncertainty associated with it. Information on the final mixture composition depends both on the calibration method and on the preparation technique. BSENISO61451:2008I SO 3002 All irhgts seredevr 1Gas analysis Preparation of calibration gas mixtures using dynamic volumetric methods Part 1: Methods o
30、f calibration 1 Scope This part of ISO 6145 specifies the calibration methods involved in the preparation of gas mixtures by dynamic volumetric techniques. It also gives a brief presentation of a non-exhaustive list of examples of dynamic volumetric techniques which are described in more detail in o
31、ther parts of ISO 6145. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IS
32、O 6142, Gas analysis Preparation of calibration gas mixtures Gravimetric method ISO 6143, Gas analysis Comparison methods for determining and checking the composition of calibration gas mixtures ISO 7504, Gas analysis Vocabulary 3 Terms and definitions For the purposes of this document, the terms an
33、d definitions given in ISO 7504 and the following apply. 3.1 uncertainty of measurement parameter, associated with the result of a measurement, that characterizes the dispersion of the values that could reasonably be attributed to the measurand NOTE 1 Values of the individual statistical uncertainti
34、es found in some methods and techniques in this part of ISO 6145 are combined with the values of systematic uncertainties that also occur in a square-root sum-of-squares manner to provide a relative combined uncertainty, or in some cases as a relative expanded uncertainty by application of the cover
35、age factor “2”. NOTE 2 In keeping with Reference 1 of the Bibliography, the uncertainty of the composition of a mixture is expressed as a relative expanded uncertainty. BSENISO61451:2008IS-5416 O1:(3002E) 2 I SO 3002 All irhgts seredevr4 Calibration methods 4.1 General 4.1.1 The uncertainty in the c
36、omposition i,M of a component i of a calibration mixture M depends at any time on a) the uncertainty of the calibration method, b) the frequency with which it is applied, c) the stability of the control devices involved in the dynamic preparation technique. To assess the uncertainty of the whole pro
37、cedure, possible instantaneous variations and drift of the principle parameters of the technique during the calibration procedure shall be considered. According to the preparation technique for the gas mixtures used, calibration can be carried out by one of the following methods: measurement of flow
38、 rate (mass or volume); comparison method; tracer method; direct chemical analysis. Table 1 shows the applicability of each calibration method to the different preparation techniques. Table 1 Calibration methods applicable to the preparation techniques Calibration methods Preparation techniques Comp
39、arison with ISO 6143 aFlow rate measurementaTraceraDirect analysis Volumetric pumps + + Continuous injection + + Capillary + + + Critical orifice + + + Thermal mass flow controllers + + + Diffusion + Saturation + Permeation + May be applicable; depends on nature of components aThe pluses refer to th
40、e measurement of a volume flow. In principle, flow rate measurement can also be performed for continuous injection methods, diffusion methods and permeation methods. Here, mass flows are measured rather than volume flows. For diffusion and permeation tubes the mass flow may be measured continuously
41、using a suspension balance. 4.1.2 In general, the principles of the methods fall into two categories, as follows. Principles in which the flow rates of component gases are measured either by volume or by mass and in which the concentration in the final mixture is calculated from the flow rate. Diffe
42、rent techniques may be used for the individual components of a mixture and these may be calibrated by different methods. The principle of measurements of individual flow rates, however, remains. Principles which operate directly on the final mixtures. BSENISO61451:2008I SO 3002 All irhgts seredevr 3
43、Since different principles are involved, they are given separately under each individual method. Since the calibration methods rely upon different principles and the equipment used for the realization of the gas flow rates is different, different units can be used to express the contents. For calibr
44、ations using the comparison method, the content is expressed as a mole fraction or mole concentration because most of the calibration gas mixtures used for the comparison, if possible, are described in this way. Using techniques based on volume flow rate leads in the first instance to volume fractio
45、ns. Recalculation of these data to mole fractions is possible but leads to an increase in the uncertainty because of the uncertainty of the density and molar-volume data. In this case, the expression in volume fractions is preferred. Calibration by the gravimetric method gives mass fractions for the
46、 contents of components in gas mixtures. These can be recalculated to mole fractions by dividing by the respective atomic or molar masses. Expression in mole fraction is therefore preferred. Under some circumstances, the total flow rate cannot be taken as the sum of two individual flow rates q Aand
47、q Bwhich have been measured separately. These problems can be caused by deviations from the ideal gas laws or by changes in conditions such as backpressure or viscosity resulting from the blending of the two flow rates. Deviations from ideal behaviour can be predicted with reasonable accuracy and ot
48、her uncertainties can be minimized by careful attention to apparatus design. 4.1.3 Flow rate measurement is normally carried out using one of the following: a) primary devices, based on absolute principles, for example: gravimetric method; b) methods which may be considered as potentially primary wh
49、en the volume of the device is determined by weighing the relevant volume of water, or another suitable liquid of higher density: mercury-sealed piston, bell-prover; c) many other devices available for the measurement of volume flow, some of which are listed below (calibration of these devices is carried out by using one of the above primary or potentially primary methods): so
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