1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58Part 15: Determination of thermal conductivity by the hot-wire (parallel) methodThe European Standa
2、rd EN 993-15:2005 has the status of a British StandardICS 81.080Methods of test for dense shaped refractory products BRITISH STANDARDBS EN 993-15:2005BS EN 993-15:2005This British Standard was published under the authority of the Standards Policy and Strategy Committee on 21 November 2005 BSI 21 Nov
3、ember 2005ISBN 0 580 46502 0Cross-referencesThe 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
4、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.Compliance with a British Standard does not of itself confer immunity from legal obligations.Summary of p
5、agesThis 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 issued since publicationAmd. No. Date CommentsA list of organizations represe
6、nted on this committee can be obtained on request to its secretary.enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK.National forewordThis British Standard is the official En
7、glish 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 It supersedes BS EN 993-15:1998 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee RPI/1, Refractory products and materials, which has the responsibility to: aid enquirers to understand the text; present to the re
8、sponsible international/European committee any EUROPEAN 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 Mtho
9、des 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 Stan
10、dard 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 s
11、uch 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 languag
12、e 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, Malt
13、a, 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 o
15、f 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 i
16、s 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-
17、15:1998. 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 perm
18、eability 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 P
19、art 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 ther
20、mal 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: Determ
21、ination 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 natio
22、nal 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, Por
23、tugal, 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 pro
24、ducts 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-tre
26、atment; 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
27、it 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
28、heat 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 squa
29、re 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 e
30、mbedded 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
31、current 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
32、the 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 p
33、oints 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 platin
34、um 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 th
35、e 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. Lea
36、ds 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 no
37、t 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/pla
38、tinum 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 wi
40、re 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 an
41、d 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 5678
42、9Figure 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 mm12467853F
43、igure 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 devic
44、e 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 ass
45、embly 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
47、shall 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 re
48、quirements 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 exampl
49、e, 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
