EN 993-15-2005 en Methods of test for dense shaped refractory products - Determination of thermal conductivity by the hot-wire (parallel) method《致密成型耐火制品的试验方法 第15部分 用热线(平行)测量法测定导热性.pdf

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1、BRITISH STANDARDBS EN 993-15:2005Methods of test for dense shaped refractory products Part 15: Determination of thermal conductivity by the hot-wire (parallel) methodThe European Standard EN 993-15:2005 has the status of a British StandardICS 81.080g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g5

2、5g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 993-15:2005This British Standard was published under the authority of the Standards Policy and Strategy Committee on 21 November 2005 BSI 21 Nove

3、mber 2005ISBN 0 580 46502 0National forewordThis British Standard is the official English language version of EN 993-15:2005. It supersedes BS EN 993-15:1998 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee RPI/1, Refractory products and materials, whic

4、h has the responsibility to:A list of organizations represented on this committee can be obtained on request to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section

5、entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue 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.Complia

6、nce with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related inter

7、national and European developments and promulgate them in the UK.Summary of pagesThis document comprises a front cover, an inside front cover, the EN title page, pages 2 to 17 and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments

8、issued since publicationAmd. No. Date CommentsEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 993-15 May 2005 ICS 81.080 Supersedes EN 993-15:1998 English version Methods of test for dense shaped refractory products - Determination of thermal conductivity by the hot-wire (parallel) method Mthod

9、es dessai pour produits rfractaires faonns denses - Partie 15: Dtermination de la conductivit thermique par la mthode du fil chaud (parallle) Prfverfahren fr dichte geformte feuerfeste Erzeugnisse - Teil 15: Bestimmung der Wrmeleitfhigkeit nach dem Heidraht- (parallel-) Verfahren This European Stand

10、ard was approved by CEN on 21 March 2005. CEN members are bound to comply with the CEN/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 su

11、ch national standards may be obtained on application to the Central Secretariat or to any CEN 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 CEN member into its own language

12、 and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta

13、, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation

14、in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 993-15:2005: EEN 993-15:2005 (E) 2 Contents page Foreword3 1 Scope 5 2 Terms and definitions .5 3 Principle5 4 Apparatus .6 5 Test pieces .8 6 Procedure .9 7 Assessment of results 11 8 Calculation and expression of

15、 results.11 9 Test report 13 Annex A (informative) Example of the determination of thermal conductivity.14 Bibliography 17 EN 993-15:2005 (E) 3 Foreword This document (EN 993-15:2005) has been prepared by Technical Committee CEN/TC 187 “Refractory products and materials”, the secretariat of which is

16、 held by BSI. 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 November 2005, and conflicting national standards shall be withdrawn at the latest by November 2005. This document supersedes EN 993-1

17、5:1998. EN 993 Methods of test for dense shaped refractory products consists of 20 Parts as follows: Part 1: Determination of bulk density, apparent porosity and true porosity Part 2: Determination of true density Part 3: Test methods for carbon-containing refractories Part 4: Determination of perme

18、ability to gases Part 5: Determination of cold crushing strength Part 6: Determination of modulus of rupture at ambient temperature Part 7: Determination of modulus of rupture at elevated temperatures Part 8: Determination of refractoriness-under-load Part 9: Determination of creep in compression Pa

19、rt 10: Determination of permanent change in dimensions on heating Part 11: Determination of resistance to thermal shock (ENV) Part 12: Determination of pyrometric cone equivalent (refractoriness) Part 13: Specification for pyrometric reference cones for laboratory use Part 14: Determination of therm

20、al conductivity by the hot-wire (cross-array) method Part 15: Determination of thermal conductivity by the hot-wire (parallel) method Part 16: Determination of resistance to sulphuric acid Part 17: Determination of bulk density of granular materials by the mercury method with vacuum Part 18: Determi

21、nation of bulk density of granular materials by the water method with vacuum Part 19: Determination of thermal expansion by a differential method Part 20: Determination of resistance to abrasion at ambient temperature EN 993-15:2005 (E) 4 According to the CEN/CENELEC Internal Regulations, the nation

22、al standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Port

23、ugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 993-15:2005 (E) 5 1 Scope This European Standard describes a hot-wire (parallel) method for the determination of thermal conductivity of refractory products and materials. It is applicable to dense and insulating shaped prod

24、ucts and to powdered or granular materials (see 6.2), for thermal conductivities of less than 25 W/m.K. The limits are imposed by the thermal diffusivity of the test material and therefore by the dimensions of the test pieces; higher thermal conductivities can be measured if larger pieces are used.

25、Electrically conducting materials cannot be measured. NOTE 1 The thermal conductivity 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 may therefore require pre-trea

26、tment; the nature and extent of such pre-treatment and the period for which the 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 standard and should be agreed between the parties concerned. NOTE 2 In general i

27、t is difficult to make measurements on anisotropic materials and the use of this method for such materials should also be agreed between the parties concerned. 2 Terms and definitions For the purposes of this document, the following terms and definitions apply. 2.1 thermal conductivity, density of h

28、eat flow rate divided by the temperature gradient, in units of watt per metre Kelvin (W/m.K) 2.2 thermal diffusivity, a pc.a= where: is the thermal conductivity is the bulk density cpis the specific heat capacity at constant pressure per weight NOTE Thermal diffusivity is expressed in units of squar

29、e metre per second (m2s-1) 2.3 power, P rate of energy transfer, in watts (W) 3 Principle The hot-wire method (parallel) is a dynamic measuring procedure based on the determination of the temperature increase against time at a certain location and at a specified distance from a linear heat source em

30、bedded between two test pieces. EN 993-15:2005 (E) 6 The test pieces are 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 embedded in the test piece and carries an electrical c

31、urrent of known power that is constant in time and along the length of the test piece. A thermocouple is fitted at a specified distance from the hot wire; the thermocouple leads running parallel to the wire (see Figure 1). The increase in temperature as a function of time, measured from the moment t

32、he heating current is switched on, is a measure of the thermal conductivity of the material from which the test pieces are made. 4 Apparatus 4.1 Furnace, electrically heated, capable of taking one or more test assemblies (see 5.1) up to a maximum temperature of 1 250 C. The temperature at any two po

33、ints 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 (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 platinu

34、m or platinum-rhodium, with a minimum length equivalent to that of the test piece. . The voltage taps should be located in the test piece with a length between the taps of about 200 mm known to the nearest 0,5 mm. Both ends of the hot wire are attached to the power source and the voltage taps to the

35、 digital multimeter (4.5). The wires to the power source may also be a continuation of the hot wire itself and shall have the same diameter as the wire within the assembly. The wires to the digital multimeter shall be of a diameter not greater than that of the hot wire when within the assembly. Lead

36、s 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 with heavy gauge cable. 4.3 Power supply, to the hot wire (4.2), which shall be stabilized a.c. or d.c., but preferably a.c., and shall not

37、 vary in power by more than 2 % during the period of measurement. A power supply to the hot wire of at least 250 W/m is required. This is equivalent to 50 W between the voltage taps for a distance of 200 mm. 4.4 Differential platinum/platinum-rhodium thermocouple, (Type R: platinum 13 % rhodium/plat

38、inum thermocouple or Type S: platinum 10% rhodium/platinum thermocouple, see Table 1) formed from a measurement thermocouple and a reference thermocouple connected in opposition (see Figure 1). The leads of the measurement thermocouple shall run parallel to the hot wire at a distance of 15 mm 1 mm (

39、see Figure 2). The output of the reference thermocouple shall be kept stable by placing it between the top outer face of the upper test piece and a cover of the same material as the test piece (see Figure 1). The diameter of the measurement thermocouple wires shall be the same as that of the hot wir

40、e and the wires of both thermocouples shall be long enough to extend outside the furnace where connections to the measuring apparatus shall be made by wire of a different type. The external connections of the thermocouple shall be isothermal. An insulating layer may be inserted between the cover and

41、 the upper test piece. NOTE Base metal thermocouples can be used at temperatures below 1 000 C. EN 993-15:2005 (E) 7 Key 1 Cover 2 Reference thermocouple 3 Optional insulating layer 4 Test piece 5 Measurement circuit 6 Measurement thermocouple 7 Test piece 8 Heating circuit 9 Voltage taps 1234 56789

42、Figure 1 Location of heating circuit and measurement circuit (differential thermocouple circuit) Key 1 Temperature/time registration device 2 Cover 3 Reference thermocouple 4 Measurement thermocouple 5 Hot wire 6 Voltmeter 7 Ammeter 8 Power source PQ = Hot-wire measurement length VAPQ15 mm12467853Fi

43、gure 2 Measurement arrangement EN 993-15:2005 (E) 8 4.5 Digital multimeter, used for measuring the current in the hot wire and the voltage drop across it, and capable of measuring both to an accuracy of at least 0,5 %. 4.6 Data acquisition system, consisting of a temperature-time registration device

44、 with a sensitivity of at least 2 V/cm or 0,05 V/Digit, or a temperature measurement of 0,01 K or better and with a time resolution better than 0,5 s. 4.7 Containers, (for use if the test is performed on powdered or granular material), having internal dimensions equal to those of the solid test asse

45、mbly specified in Clause 5, so that the test assembly shall consist of two sections as specified in 5.1. The bottom container shall have four sides and a base, and the top container shall have four sides only, plus a detachable cover (see Figure 3). NOTE Containers should be of a material that will

46、not react with the test piece at the test temperature and should not be electrically conducting. Key 1 Cover 2 Reference thermocouple 3 Containers 4 Measurement thermocouple 5 Hot wire 21345Figure 3 Container with hot wire and thermocouple laid on it 5 Test pieces 5.1 Dimensions Each test assembly s

47、hall consist of two identical test pieces, not less than 200 mm x 100 mm x 50 mm in size. NOTE 1 It is recommended that the size of each test piece be 230 mm x 114 mm x 64 mm or 230 mm x 114 mm x 76 mm. Standard-size bricks can then be used as the pieces forming the test assembly, subject to the req

48、uirements of 5.2. NOTE 2 The limits of this method are imposed by the dimensions of the test pieces. With larger test pieces, higher values of thermal conductivity can be measured. The distance between the hot wire and thermocouple should be extended to the same ratio as the test pieces. For example

49、, with a test piece 230 mm x 180 mm x 95 mm, a thermal conductivity of about 40 W/m.K can be measured. EN 993-15:2005 (E) 9 5.2 Surface flatness The surfaces of the two test pieces forming the test assembly which are in contact with each other shall, if necessary, be ground so that the deviation from flatness between two points not less than 100 mm apart is not more than 0,2 mm. 5.3 Grooves in dense materials In dense materials, grooves to accommodate the hot wire and the measurement thermocouple shall be machined in the lower face of t