1、BRITISH STANDARD BS EN 61207-3:2002 Gas analyzers Expression of performance Part 3: Paramagnetic oxygen analyzers The European Standard EN 61207-3:2002 has the status of a British Standard ICS 71.040.40; 19.040 BS EN 61207-3:2002 This British Standard was published under the authority of the Standar
2、ds Policy and Strategy Committee on 10 June 2003 BSI 10 June 2003 ISBN 0 580 41904 5 National foreword This British Standard is the official English language version of EN 61207-3:2002. It is identical with IEC 61207-3:2002, including Corrigendum 1:January 2003 and Corrigendum 2:May 2003. The UK par
3、ticipation in its preparation was entrusted by Technical Committee GEL/65, Measurement and control, to Subcommittee GEL/65/4, Process instruments for gas and liquid analysis, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its s
4、ecretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Ca
5、talogue or of British Standards Online. 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 does not of itself confer immunity from legal obligations. aid enquirers to understan
6、d the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a
7、front cover, an inside front cover, the EN title page, pages 2 to 28, an inside back cover and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEAN STANDARD EN 61207-3 NORME EUR
8、OPENNE EUROPISCHE NORM May 2002 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2002 CENELEC - All rights of exploitation in any
9、 form and by any means reserved worldwide for CENELEC members. Ref. No. EN 61207-3:2002 E ICS 71.040.40; 19.040 Supersedes EN 61207-3:1999 English version Gas analyzers - Expression of performance Part 3: Paramagnetic oxygen analyzers (IEC 61207-3:2002) Analyseurs de gaz - Expression des qualits de
10、fonctionnement Partie 3: Analyseurs doxygne paramagntiques (CEI 61207-3:2002) Gasanalysegerte - Angabe zum Betriebsverhalten Teil 3: Paramagnetische Sauerstoffanalysegerte (IEC 61207-3:2002) This European Standard was approved by CENELEC on 2002-05-01. CENELEC members are bound to comply with the CE
11、N/CENELEC Internal Regulations which stipulate 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 Central Secretariat or to
12、 any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official
13、versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.Foreword The text of documen
14、t 65D/79/FDIS, future edition 2 of IEC 61207-3, prepared by SC 65D, Analyzing equipment, of IEC TC 65, Industrial-process measurement and control, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 61207-3 on 2002-05-01. This European Standard supersedes EN 61207-3:1999
15、. The following dates were fixed: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2003-02-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2005-05-01 This Eur
16、opean Standard shall be used in conjunction with EN 61207-1. Annexes designated “normative“ are part of the body of the standard. Annexes designated “informative“ are given for information only. In this standard, annex ZA is normative and annexes A and B are informative. Annex ZA has been added by C
17、ENELEC. _ Endorsement notice The text of the International Standard IEC 61207-3:2002 was approved by CENELEC as a European Standard without any modification. _ Page2 EN612073:2002CONTENTS 1 Scope and object5 2 Normative references .5 3 Definitions 6 4 Procedures for specification .10 4.1 Specificati
18、on of essential ancillary units and services10 4.1.1 Sampling system .10 4.1.2 Services 10 4.2 Additional characteristics related to specification of performance. .11 4.3 Important aspects related to specification of performance .11 4.3.1 Rated range of ambient temperature .11 4.3.2 Rated range of s
19、ample gas temperature 11 4.3.3 Rated range of ambient pressure.12 4.3.4 Rated range of sample pressure12 4.3.5 Rated range of sample flow .12 4.3.6 Rated range of sample dew point.12 4.3.7 Rated range of sample particulate content.12 4.3.8 Rated range of interference errors.13 4.3.9 Rated range of l
20、inearity error.13 5 Procedures for compliance testing13 5.1 Introduction .13 5.1.1 Test equipment13 5.2 Testing procedures14 5.2.1 Interference error 14 5.2.2 Wet samples14 5.2.3 Delay times, rise time, fall time15 Annex A (informative) Interfering gases .22 Annex B (informative) Methods of preparat
21、ion of water vapour in test gases25 Annex ZA (normative) Normative references to international publications with their corresponding European publications .27 Bibliography28 Figure 1 Magnetic auto-balance system with current feedback.15 Figure 2 Thermomagnetic oxygen sensor.16 Figure 3 Differential
22、pressure oxygen sensor .17 Figure 4 Typical sampling systems Filtered and dried system with pump for wet samples 18 Figure 5 General test arrangement Dry gases.19 Figure 6 Typical sampling system Steam-aspirated system with water wash for wet samples 20 Figure 7 Test apparatus to apply gases and wat
23、er vapour to analysis systems 21 Table A.1 Zero correction factors for current gases23 Page3 EN612073:2002 INTRODUCTION Paramagnetic oxygen analyzers respond to partial pressure and not volumetric concentration. They are used in a wide range of industrial, laboratory and other applications where the
24、 rated measuring range of the analyzer is between 0 % to 1 % and 0 % to 100 %, at reference pressure. Only a few gases display paramagnetism (for example, oxygen, nitric oxide and nitrogen dioxide). Oxygen has a particularly strong paramagnetic susceptibility (see annex A). By employing this particu
25、lar property of oxygen, analyzers have been designed which can be highly specific to the measurement in most industrial applications, where, for example, high background levels of hydrocarbons may be present. There are several different techniques described for measuring the paramagnetic properties
26、of oxygen, but three main methods have evolved over many years of commercial application. The three methods are: automatic null balance; thermomagnetic or magnetic wind; differential pressure or Quincke. These methods all require the sample gas to be clean and dry, though some versions work at eleva
27、ted temperatures so that samples that are likely to condense at a lower temperature can be analyzed. Because of this requirement, analyzers often require a sample system to condition the sample prior to measurement. Page4 EN612073:2002GAS ANALYZERS EXPRESSION OF PERFORMANCE Part 3: Paramagnetic oxyg
28、en analyzers 1 Scope and object This part of IEC 61207 applies to the three main methods outlined in the introduction. It considers essential ancillary units and applies to analyzers installed indoors and outdoors. NOTE Safety critical applications can require an additional requirement of system and
29、 analyzer specifications not covered in this standard. This standard is intended to specify terminology and definitions related to the functional performance of para- magnetic gas analyzers for the measurement of oxygen in a source gas; to unify methods used in making and verifying statements on the
30、 functional performance of such analyzers; to specify what tests should be performed to determine the functional performance and how such tests should be carried out; to provide basic documents to support the application of standards of quality assurance (ISO 9001, ISO 9002 and ISO 9003). 2 Normativ
31、e 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. IEC 60654-1:1993, Industrial-process
32、 measurement and control equipment Operating conditions Part 1: Climatic conditions IEC 61115:1992, Expression of performance of sample handling systems for process analyzers IEC 61207-1:1994, Expression of performance of gas analyzers Part 1: General ISO 9001:2000, Quality management systems Requir
33、ements ISO 9002:1994, Quality systems Model for quality assurance in production, installation and servicing ISO 9003:1994, Quality systems Model for quality assurance in final inspection and test Page5 EN612073:20023 Definitions For the purposes of this part of IEC 61270, the following definitions a
34、pply. 3.1 magnetic susceptibility measure (X) of the variation of the intensity of a magnetic field H, existing in a vacuum, when the vacuum is substituted (filled) by the test substance H H H X = 1(1) where H is the magnetic field intensity in vacuum; H 1is the magnetic field intensity in the test
35、substance. 3.1.1 paramagnetism substances causing an increase of the magnetic field intensity (X 0) 3.1.2 diamagnetism substances causing a diminution of the magnetic field intensity (X 0 because H 1 H) 3.1.3 specific magnetic susceptibility ratio of magnetic susceptibility as follows: D X X = s(2)
36、where D is the density of the considered substance, expressed in g cm 3at 273,15 K (0 C) and 101,3 kPa (= 1 bar). The measuring unit of X sis therefore cm 3 g 1 . 3.1.4 molar magnetic susceptibility the molar magnetic susceptibility X m is the specific magnetic susceptibility multiplied by the molec
37、ular weight of the substance considered: M X X = s m(3) where M is expressed in grammes per mole (g mol 1 ) (for oxygen M = 32). The measuring unit of X mis therefore cm 3 g 1 g mol 1= cm 3 mol 1 . NOTE 1 Electrons determine the magnetic properties of matter in two ways: an electron can be considere
38、d as a small sphere of negative charge spinning on its axis. This spinning charge produces a magnetic moment; an electron travelling in an orbit around a nucleus will also produce a magnetic moment. Page6 EN612073:2002It is the combination of the spin moment and the orbital moment that governs the r
39、esulting magnetic properties of an individual atom or ion. In paramagnetic materials, the main contribution to the magnetic moment comes from unpaired electrons. It is the configuration of the orbital electrons and their spin orientations that establish the paramagnetism of the oxygen molecule and d
40、istinguish it from most other gases. NOTE 2 When paramagnetic gases are placed within an external magnetic field, the flux within the gas is higher than it would be in a vacuum, thus paramagnetic gases are attracted to the part of the magnetic field with the strongest magnetic flux. On the contrary,
41、 diamagnetic substances contain magnetic dipoles which cancel out some lines of force from the external field; thus diamagnetic gases are subject to repulsion by the magnetic flux. NOTE 3 The molar magnetic susceptibility of oxygen is inversely proportional to the absolute temperature T according to
42、 X m = (1010557 / T ) 10 6 cm 3 mol 1 . (only for oxygen). NOTE 4 A full understanding of paramagnetism and diamagnetism can be obtained from physics and inorganic chemistry textbooks. The explanation in this standard is to give the user of paramagnetic oxygen analyzers a simple understanding of the
43、 physical property utilized. 3.2 automatic null balance analyzer this type of analyzer uses, as a general principle of operation, the displacement of a body containing a vacuum or a diamagnetic gas, from a region of high magnetic field by para- magnetic oxygen molecules (see figure 1). The measuring
44、 cell typically employs a glass dumb-bell, with the spheres containing nitrogen, suspended on a torsion strip between magnetic pole pieces that concentrate the flux around the dumb-bell. The measuring cell has to be placed in a magnetic circuit. The dumb-bell is then deflected when oxygen molecules
45、enter the measuring cell, a force being exerted on the dumb-bell by the oxygen molecules which are attracted to the strongest part of the magnetic field. By use of optical levers, a feed-back coil, and suitable electronics, an output that is directly proportional to the partial pressure of oxygen ca
46、n be achieved. The transducer is usually maintained at a constant temperature to prevent the variations in magnetic susceptibility with temperature from introducing errors. Additionally, the elevated temperature helps in applications where the sample is not particularly dry. Some analyzers are desig
47、ned so that the transducer operates at a temperature in excess of 373,15 K (100 C) to further facilitate applications where condensates would form at lower temperature. Page7 EN612073:20023.3 thermomagnetic (magnetic-wind) analyzers this type of analyzer utilizes the temperature dependence of the ma
48、gnetic susceptibility to generate a magnetically induced gas flow which can then be measured by a flow sensor. The sample gas passes into a chamber designed in such a way that the inlet splits the flow (see figure 2). The two flows recombine at the outlet. A connecting tube is placed centrally with
49、the flow sensor wound on it. Half of the connecting tube is placed between the poles of a strong magnet. The flow sensor is effectively two coils of wire heated to about 353,15 K (80 C) by passage of a current. The cold oxygen molecules are diverted by the magnetic field into the central tube, and, as they heat up, their magnetic susceptibility is reduced and more cold oxyg
