BS EN ISO 8894-1-2010 Refractory materials - Determination of thermal conductivity - Hot-wire methods (cross-array and resistance thermometer)《耐火材料 导热系数测定 热线法(正交数组和电阻温度计)》.pdf

《BS EN ISO 8894-1-2010 Refractory materials - Determination of thermal conductivity - Hot-wire methods (cross-array and resistance thermometer)《耐火材料 导热系数测定 热线法(正交数组和电阻温度计)》.pdf》由会员分享，可在线阅读，更多相关《BS EN ISO 8894-1-2010 Refractory materials - Determination of thermal conductivity - Hot-wire methods (cross-array and resistance thermometer)《耐火材料 导热系数测定 热线法(正交数组和电阻温度计)》.pdf（26页珍藏版）》请在麦多课文档分享上搜索。

1、BS EN ISO8894-1:2010ICS 81.080NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDRefractory materials Determination ofthermal conductivityPart 1: Hot-wire methods (cross-arrayand resistance thermometer) (ISO8894-1:2010)This British Standardwas published under theau

2、thority of the StandardsPolicy and StrategyCommittee on 30 June2010 BSI 2010ISBN 978 0 580 63577 9Amendments/corrigenda issued since publicationDate CommentsBS EN ISO 8894-1:2010National forewordThis British Standard is the UK implementation of EN ISO 8894-1:2010.It supersedes BS EN 993-14:1998 whic

3、h is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee RPI/1, Refractory products and materials.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisio

4、nsof a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunityfrom legal obligations.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 8894-1 May 2010 ICS 81.080 Supersedes EN 993-14:1998English Version Refractory materials - Deter

5、mination of thermal conductivity - Part 1: Hot-wire methods (cross-array and resistance thermometer) (ISO 8894-1:2010) Matriaux rfractaires - Dtermination de la conductivit thermique - Partie 1: Mthodes du fil chaud (croisillon et thermomtre rsistance) (ISO 8894-1:2010) Feuerfeste Werkstoffe - Besti

6、mmung der Wrmeleitfhigkeit - Teil 1: Heidrahtverfahren (Kreuzverfahren und Widerstandsthermometer-Verfahren) (ISO 8894-1:2010) This European Standard was approved by CEN on 6 May 2010. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving

7、 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 Standard exists in three official versi

8、ons (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 standards bodies of Austria, Belgium,

9、 Bulgaria, Croatia, 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 Kingdom. EUROPEAN COMMITTE

10、E FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 8894-1:2010: EBS EN ISO 8894-1:2010EN

11、 ISO 8894-1:2010 (E) 3 Foreword This document (EN ISO 8894-1:2010) has been prepared by Technical Committee ISO/TC 33 “Refractories“ in collaboration with Technical Committee CEN/TC 187 “Refractory products and materials” the secretariat of which is held by BSI. This European Standard shall be given

12、 the status of a national standard, either by publication of an identical text or by endorsement, at the latest by November 2010, and conflicting national standards shall be withdrawn at the latest by November 2010. Attention is drawn to the possibility that some of the elements of this document may

13、 be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 993-14:1998. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to i

14、mplement this European Standard: Austria, Belgium, Bulgaria, Croatia, 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,

15、 Switzerland and the United Kingdom. Endorsement notice The text of ISO 8894-1:2010 has been approved by CEN as a EN ISO 8894-1:2010 without any modification. BS EN ISO 8894-1:2010ISO 8894-1:2010(E) ISO 2010 All rights reserved iiiContents Page Foreword iv 1 Scope1 2 Terms and definitions .1 3 Princ

16、iple2 4 Apparatus.2 5 Test pieces .8 6 Procedure.9 7 Assessment of results 10 8 Calculation and expression of results 11 9 Precision.11 10 Test report11 Annex A (informative) Data conversion of change in resistance to change in temperature 13 Annex B (informative) Examples of thermal conductivity me

17、asurements18 BS EN ISO 8894-1:2010ISO 8894-1:2010(E) iv ISO 2010 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out thro

18、ugh ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collabor

19、ates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standa

20、rds. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of t

21、his document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 8894-1 was prepared by Technical Committee ISO/TC 33, Refractories. This second edition cancels and replaces the first edition (ISO 8894-1:1987), which has been revi

22、sed to include a hot-wire “resistance thermometer” method, as well as the hot-wire “cross-array” method and to harmonize the text with that of EN 993-14:1998, Methods of testing dense shaped refractory products Part 14: Determination of thermal conductivity by the hot-wire (cross-array) method, prep

23、ared by CEN/TC 187. ISO 8894 consists of the following parts, under the general title Refractory materials Determination of thermal conductivity: Part 1: Hot-wire methods (cross-array and resistance thermometer) Part 2: Hot-wire method (parallel) BS EN ISO 8894-1:2010INTERNATIONAL STANDARD ISO 8894-

24、1:2010(E) ISO 2010 All rights reserved 1Refractory materials Determination of thermal conductivity Part 1: Hot-wire methods (cross-array and resistance thermometer) 1 Scope This part of ISO 8894 describes the hot-wire methods (“cross-array” and “resistance thermometer”) for the determination of the

25、thermal conductivity of non-carbonaceous, dielectric refractory products and materials. This methods are applicable to dense and insulating refractories (shaped products, refractory castables, plastic refractories, ramming mixes, powdered or granular materials) with thermal conductivity values less

26、than 1,5 W/mK (“cross-array”) and less than 15 W/mK (“resistance thermometer”) and thermal diffusivity values less than 5 106m2/s. Thermal conductivity values can be determined at a room temperature up to 1 250 C. The maximum temperature (1 250 C) can be reduced by the maximum service limit temperat

27、ure of the refractory, or by the temperature at which the refractory is no longer dielectric. NOTE 1 In general, it is difficult to make accurate measurements on anisotropic materials and the use of this method for such materials can be agreed between the parties concerned. NOTE 2 The thermal conduc

28、tivity of products with a hydraulic or chemical bond can be affected by the appreciable amount of water that is retained after hardening or setting and is released on firing. These materials might therefore require pre-treatment; the nature and extent of such pre-treatment and the period for which t

29、he test piece is held at the measurement temperature as a preliminary to carrying out the test, are details that are outside the scope of this part of ISO 8894 and are agreed between the parties concerned. NOTE 3 The measurement of thermal conductivity is not sufficiently uncomplicated for an engine

30、er to expect to achieve correct results without having particular work experience and if the work is based exclusively on this standard. Sufficient experience of measuring temperatures and laboratory skills are imperative. 2 Terms and definitions For the purposes of this document, the following term

31、s and definitions apply. 2.1 thermal conductivity density of heat flow rate divided by the temperature gradient NOTE Thermal conductivity is expressed in watts per metre kelvin (W/mK). 2.2 thermal diffusivity a thermal conductivity divided by the bulk density times the specific heat capacity NOTE 1

32、a = / cpBS EN ISO 8894-1:2010ISO 8894-1:2010(E) 2 ISO 2010 All rights reservedwhere: is the thermal conductivity; is the bulk density; cpis the specific heat capacity at constant pressure per weight. NOTE 2 Thermal diffusivity is expressed in units of square metres per second (m2s1). 2.3 power P rat

33、e of energy transfer NOTE Power is expressed in watts (W). 3 Principle Both the hot-wire “cross-array” and “resistance thermometer” methods are dynamic measuring procedures based on the determination of the temperature increase against time of a linear heat source (hot wire) embedded between two tes

34、t pieces which make up the test assembly. The test assembly is heated in a furnace to a specified temperature and maintained at that temperature. Further local heating is provided by a linear electrical conductor (the hot wire) that is symmetrically embedded in the test assembly and carries an elect

35、rical current of known power that is constant in time and along the length of the test pieces. The increase in temperature as a function of time follows a logarithmic law, and is measured and recorded from the moment the local heating current is switched on. The thermal conductivity of the test piec

36、es is calculated using the rate of temperature increase and the power input. For the “cross-array“ method, the temperature increase is measured using a thermocouple that is welded to the hot wire at its centre. The thermocouple leads are perpendicular to the hot wire. For the “resistance thermometer

37、“ method, the temperature increase is measured by using the hot wire itself as both heat source and temperature sensor. An integral temperature measurement of the hot wire is carried out over the length between the voltage taps. The change in resistance of this part of the hot wire is determined. Fr

38、om these data, its temperature increase is calculated. The mathematical procedure is described in Annex A. 4 Apparatus NOTE A block diagram of a suggested test apparatus for the “cross-array” method is shown in Figure 1 and for the “resistance thermometer” method in Figure 2. 4.1 Furnace, electrical

39、ly heated, capable of taking one or more test assemblies (see 5.1) up to the required maximum test temperature. The temperature at any two points in the region occupied by the test pieces shall not differ by more than 10 K. The temperature measured on the outside of the test assembly during a test (

40、of duration about 15 min) shall not vary by more than 0,5 K, and shall be known with an accuracy of 10 K. 4.2 Hot wire, preferably of platinum or platinum-rhodium, with a minimum length equivalent to that of the test piece and a diameter not more than 0,5 mm. Both ends of the hot wire are attached t

41、o the power supply (4.4). Leads outside the assembly shall consist of two or more tightly twisted wires of 0,5 mm diameter. The current lead connections external to the furnace shall be made of heavy gauge cable. BS EN ISO 8894-1:2010ISO 8894-1:2010(E) ISO 2010 All rights reserved 3Key 1 hot-wire po

42、wer supply; a.c. source 1 kHz 8 heating circuit 2 reference thermocouple Tr 9 voltage taps 3 hot-wire power control unit 10 current measurement 4 test assembly 11 data acquisition system and computer 5 cold junction of thermocouples 12 absolute signal (Ti) 6 measurement thermocouple Ti 13 difference

43、 signal (Ti Tr) 7 shunt Figure 1 Block diagram of apparatus for “cross-array” method BS EN ISO 8894-1:2010ISO 8894-1:2010(E) 4 ISO 2010 All rights reservedKey 1 hot-wire power supply; a.c. 1 kHz 9 a.c. voltage measurement 2 thermocouple 10 a.c. current measurement 3 hot-wire power control unit 11 da

44、ta acquisition system and computer 4 test assembly 12 absolute signal R 5 amplifier 13 difference signal R 6 voltage taps 14 d.c.source 100 mA 7 shunt 15 resistance measurement circuit 8 heating circuit Figure 2 Block diagram of apparatus for “resistance thermometer” method BS EN ISO 8894-1:2010ISO

45、8894-1:2010(E) ISO 2010 All rights reserved 54.3 Voltage taps, made of the same material as the hot wire. The welded connections to the hot wire should be located in the test piece with a distance of about 200 mm, known to the nearest 0,5 mm. The wires shall be of a diameter not greater than that of

46、 the hot wire. Both ends of the voltage taps are attached to the hot-wire power control unit (4.6). 4.4 Power supply, to the hot wire (4.2). For the electrical heating of the hot wire during a single measurement (6.7) an adequate power supply is required. 4.4.1 For the “cross-array” method, the powe

47、r supply shall be stabilized a.c. or d.c., but preferably a.c., and shall not vary in power by more than 2 % during the period of measurement. It shall be variable between 1 W/m and 20 W/m. This is equivalent to 0,2 W to 4 W between the voltage taps for a distance of 200 mm (see 6.5, Note). 4.4.2 Fo

48、r the “resistance thermometer” method, the power supply shall be stabilized a.c., and shall not vary in power by more than 2 % during the period of measurement. It shall be variable between 1 W/m and 125 W/m. This is equivalent to 0,2 W and 25 W between the voltage taps for a distance of 200 mm (see

49、 6.5, Note). 4.5 Equipment for the measurement of the temperature increase of the hot wire. The following arrangements for the “cross-array” and “resistance thermometer” methods shall be applied. 4.5.1 “Cross-array” method. For the “cross-array” method, use a differential platinum/platinum-rhodium thermocouple (Type S: platinum 10 % rhodium/platinum thermocouple or Type R: platinum 13 % rhodium/ platinum thermocouple) formed from a measurement thermocouple (Ti) which is welded to the hot wire at its cen