1、W 3qOq563 0342743 783 W BRITISH STANDARD Expression of performance of gas analyzers Part 2. Oxygen in gas (utilizing high- t emperature elec trochernical sensors) The European Standard EN 61207-2 : 1994 has the status of a British Standard UDC 621.317.79 : 543.27 : 543.25 BS EN 61207-2 : 1994 IEC 12
2、07-2 : 1994 BS EN 61207-2 : 1994 Amd. No. m 3404583 0342744 b3T m Date lkxt affected Cooperating organizations The European Committee for Electrotechnical Standardization (CENELEC), under whose supervision this European Standard was prepared, comprises the national committees of the following countr
3、ies: Austria Italy Belgium Luxembourg Denmark Netherlands Finland Norway France Portugal Germany Spain Greece Sweden Iceland Switzerland Ireland United Kingdom This British Standard, having been prepared under the direction of the Electrotechnical Sector Board , was published under the authority of
4、the Standards Board and comes into effect on 15 November 1994 O BSI 1994 The following BSI references relate to the work on this standard: Committee reference PCU- Draft for comment 85121733 DC ISBN O 580 23614 9 m 3404583 0342745 556 W BS EN 61207-2 : 1994 Contents Page Cooperating organizations In
5、side front cover National foreword i Foreword 2 Bxt of EN 61207-2 3 National annex NA (informative) Committees responsible Inside back cover National annex NB (informative) Cross-references Inside back cover National foreword This British Standard has been prepared under the direction of the Electro
6、technical Sector Board and is the English language version of EN 61207-2 : 1994 Expression of perfmance of gas analyzers. Part 2: Oxygen in gas (utilixing high-temperature electrotechnical sensors), published by the European Committee for Electrotechnical Standardization (CENELEC). It is identical w
7、ith IEC 1207-2 : 1994 including Corrigendum, May 1994, published by the International Electrotechnical Commission (IEC). IEC 1207-2 constitutes Part 2 of the IEC 1207 series of publications under the general title: Expression of performance of gas analyzers. Other Parts are as follows: part 1. Gener
8、al Part 2. Oxygen in gas (utilizing high-temperature electrotechnical sensors) Part 6. Photometric analyzers Part 7. Infra-red analyzers Parts 3, 4 and 5 are under consideration. The following print types are used in this standard: requirements proper: in roman type; - - notes: in smaller roman type
9、. Compliance with a British Standard does not of itself confer immunity from legal obligations. i 3404583 OL4274b 492 = EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 61207-2 June 1994 UM: 62 1.317.79:543.27:543.25 Descriptors: Gaseous mixtures, oxygen in gaseous mixtures, gas analyzers, perfo
10、rmance of gas analyzers, high temperature electrochemical sensors English version Expression of performance of gas analyzers Part 2: Oxygen in gas (utilizing high-temperature electrochemical sensors) (IEC 1207-2 : 1994 + corrigendum 1994) Expression des qualits de fonctionnement des analyseurs de ga
11、z Partie 2: Oxygne contenu dans le gaz (utilisant des capteurs lectrochimiques haute temprature) Hochtemperatur-Sensoren) Angabe zum Betriebsverhalten von Gasanalysat oren %il 2: Sauerstoff in Gas (unter Verwendung von elektrochemischen (CE1 1207-2 : 1994) (IEC 1207-2 : 1994) This European Standard
12、was approved by CENELEC on 1994-05-15. CENELEC members are bound to comply with the CENKENELEC 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 su
13、ch national standards may be obtained on application to the Central Secretariat or to 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
14、language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Swede
15、n, Switzerland and United Kingdom. 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 O 1994 Copyright reserved to CENELEC members Re
16、f. No. EN 61207-2 : 1994 E Previous page is blank m 3404583 0342747 329 m Page 2 EN 61207-2 : 1994 Foreword The text of document 65D(C0)3, as prepared by Subcommittee 65D: Analyzing equipment, of IEC Technical Committee 65: Industrial-process measurement and control, was submitted to the IEC-CENELEC
17、 parallel vote in October 1993. The reference document was approved by CENELEC as EN 61207-2 on 15 May 1994. The following dates were fixed: - latest date of publication of an identical national standard (dop) 1995-05-15 - latest date of withdrawal of conflicting national standards (dow) 1995-05-15
18、For products which have complied with the relevant national standard before 1995-05-15, as shown by the manufacturer or by a certification body, this previous standard may continue to apply for production until 2000-05-15. Annexes designated normative are part of the body of the standard. Annexes de
19、signated informative are given only for information. In this standard, annex ZA is normative. W 3404583 0342748 265 Page 3 EN 61207-2 : 1994 CONTENTS FOREWORD . INTRODUCTION Clause 1 Scope 2 Normative references 3 Definitions . 4 Procedures for specification . 4.1 Specification of essential units an
20、d ancillary services . 4.2 Additional terms related to the specification of performance 4.3 Important terms related to the specification of performance . 5 Procedures for compliance testing . 5.1 General . 5.2 Testing procedures . 5-3 Output fluctuation . 5.4 Delay time. rise time and fall time Figu
21、res . 2 4 5 5 6 8 9 9 10 10 10 11 11 12 13 Annex ZA (normative) Other international publications quoted in this standard with the references of the relevant European publications . 15 3404583 0342749 LTL Page 4 EN 61207-2 : 1994 INTRODUCTION This pari of IEC 1207 includes the terminology, definition
22、s, statements and tests that are specific to oxygen analyzers, which utilise high-temperature electrochemical sensors. Oxygen analyzers employing high-temperature electrochemical sensors operating at tem- peratures usually in excess of 600 OC, have a wide range of applications for the measurement of
23、 oxygen in gas samples. Such samples are typically the result of a combustion process. Two main types of analyzer exist, the in situ analyzer, where the sensor is positioned within the process duct work, and the “extractive“ analyzer, where the sample is drawn from the duct via a simple sample syste
24、m and presented to the sensor. An analyzer will typically comprise a sensor head, mounted on the process duct, and a control unit remotely mounted, with interconnecting cable. = 3q04583 0342750 913 Page 5 EN 61207-2 : 1994 EXPRESSION OF PERFORMANCE OF GAS ANALYZERS - Part 2: Oxygen in gas (utilizing
25、 high-temperature electrochemical sensors) 1 Scope This part of IEC 1207 applies to all aspects of analyzers using high-temperature electro- chemical sensors for the measurement of oxygen in gas. It should be used in conjunction with IEC 1207-1. It applies to in-situ and extractive analyzers and to
26、analyzers installed indoors and out- doors. The object of this pari is: - to specify the terminology and definitions related to the functional performance of gas analyzers, utilizing a high-temperature electrochemical sensor, for the continuous measurement of oxygen concentration in a sample of gas;
27、 - to unify methods used in making and verifying statements on the functional perform- ance 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 stan
28、dards of quality assurance IS0 9001, IS0 9002 and IS0 9003. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this pari of IEC 1207. At the time of publication, the editions indicated were valid. All normative
29、documents are subject to revision, and parties to agreements based on this part of IEC 1207 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. Members of IEC and IS0 maintain registers of currently valid International Standa
30、rds. I EC 654, Operating conditions for industrial-process measurement and control equipment IEC 1207-1 : 1994, Expression of performance of gas analyzers - Part i: General 3404583 OLg2751 85T 9 Page 6 EN 61207-2 : 1994 3 Definitions 3.1 High-temperature electrochemical sensor The high-temperature e
31、lectrochemical sensor can be constructed in two basic forms: a) Galvanic concentration cell. b) Ion pump cell. 3.1.1 galvanic concentration cell: Most commercially available analyzers employ the galvanic concentration cell consisting of two gas chambers, separated by an oxygen ion conducting solid e
32、lectrolyte, and provided with a porous electrode on each side. NOTES 1 Platinum is frequently used for the electrodes, and the ceramic electrolyte is usually zirconium oxide, hilly or partially stabilized with yttrium oxide, calcium oxide or thorium oxide, which when heated above 600 “C. allows the
33、charge transfer mechanism to be predominantly oxygen ion conduction. 2 When the sensor is brought to a temperature at which the solid electrolyte conducts oxygen ions and the emf. between the two electrodes is measured, the output will be related to the logarithm of the ratio of the partial pressure
34、s of oxygen at each of the electrodes in accordance with the Nernst equation: RT i E=- In - 4F p2 (3) p, E(mV) P 0,0496 Tlg, pz where P, P2 E R T F k Thus, provided the oxygen partial pressure is known at one electrode (P,), then the potential difference between the two electrodes will enable the un
35、known oxygen pressure to be determined at the other electrode is the partial pressure of oxygen in the reference gas; is the partial pressure of oxygen in the sample gas; is the electromotive force output from the cell inV; is the gas constant (8,3144 J K- mol-); is the absolute temperature (K); is
36、the Faraday constant (96,484 56 x 10 C mol-); is the Nemstian coefficient (slope factor). (P I is the current (A); f is the Faraday constant (96,484 56 x lo3 C mol”). This is used generally in two basic configurations. 3.1.2.1 Limiting current - a diffusion pinhole limits the rate of arrival of oxyg
37、en molecules at the measuring electrode, and a constant voltage across the electrodes ensures that all the oxygen arriving at the measuring electrode is pumped to the other side. The current generated is quantitatively related to the number of oxygen molecules transferred. 3.1.2.2 Fixed volume - thi
38、s configuration consists of two sets of electrodes arranged across a small fixed volume. The first set comprises a concentration cell, the second set the ion pump. The volume is initially swept of oxygen molecules to a predetermined low level. Pump action is then initiated until the concentration ce
39、ll reading shows that the oxy- gen concentration in the volume and that outside at the sample side, are the same. The current and time required to achieve this are related to the oxygen concentration of the sample gas. M 3404563 0342753 622 M Page 8 EN 61207-2 : 1994 3.2 reference gas: All analyzers
40、 using the high-temperature electrochemical concen- tration cell require a reference sample of known and constant composition - usually air is employed. NOTE - The sensor output is a function of the partial pressure of oxygen in the sample, provided the reference has a constant partial pressure of o
41、xygen. 3.3 situated in the sample; however the sensor may require a filter to remove particulates. in situ analyzer: The in situ analyzer has the high-temperature electrochemical sensor One version of the in situ analyzer controls the temperature of the sensor in the range 600 OC to 800 OC. In this
42、case the sample temperature cannot exceed the control temperature. The second version relies on the temperature of the sample to attain the operating temperature. It is then necessary to measure the sensor temperature to enable the oxygen value to be calculated. 3.4 extractive analyzer: In the “extr
43、active“ analyzer the sensor head is installed outside the gas stream to be measured, and the sample is drawn through a sample probe and presented to the sensor which is maintained at a controlled temperature to ensure ionic conduction (typically in the range 600 “C to 800 OC). The extractive analyze
44、r may require a filter to remove particulates, and a driving force (often an aspirator) to move the sample. The pipework involved should be minimized and maintained above the dew-point of any condensible species to prevent formation of any condensation. 3.5 mable gases, vapours or dusts. hazardous a
45、rea: An area where there is a possibility of release of potential flam- 3.6 flametrap: A device used to prevent a flame, resulting from the ignition of a flam- mable gas mixture, from propagating. 3.7 essential anclllary units: Essential ancillary units are those without which the analyzer will not
46、operate (e.g. pumps for aspirators, calibration systems, etc.). 4 Procedures for specification The procedures for specification are detailed in IEC 1207-1. This covers: - operation and storage requirements; - specification of ranges of measurement and output signals; - limits of errors; - recommende
47、d reference values and rated ranges of influence quantities. In this part of IEC 1207, specifications of ranges for ancillary equipment are given. Additional terms for specification of performance, and important aspects of performance relevant to high-temperature electrochemical sensors are also det
48、ailed. 3404583 0342754 569 W Page 9 EN 61207-2 : 1994 4.1 All oxygen analyzers utilizing high-temperature electrochemical concentration cells require a reference gas supply. This is usually air, filtered to remove moisture and oil. Analyzers require facilities for calibration after installation. Bot
49、tled calibration gases and pressure regulation facilities are generally required. Specification of essential units and ancillary services 4.1.1 Reference gas pressure in practice may have small effects on error. Rated range of reference gas pressure Also the reference gas pressure will affect reference gas flow. High flows can cause cooling of electrodes and subsequent errors. 4.1.2 Rated range of calibration gas pressure Calibration gas pressure may have small effects on error. Also calibration gas pressure will affect calibration gas flow in a similar manner as
