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1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN 993-15:1998 The Eur
2、opean Standard EN 993-15:1998 has the status of a British Standard ICS 81.080 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Methods of test for dense shaped refractory products Part 15: Determination of thermal conductivity by the hot-wire (parallel) method Licensed Copy: sh
3、effieldun sheffieldun, na, Tue Nov 07 06:16:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI This British Standard, having been prepared under the direction of the Sector Board for Materials and Chemicals, was published under the authority of the Standards Board and comes into effect on 15 August 1998
4、BSI 1998 ISBN 0 580 29858 2 BS EN 993-15:1998 Amendments issued since publication Amd. No.DateText affected National foreword This British Standard is the English language version of EN 993-15:1998. The UK participation in its preparation was entrusted by Technical Committee RPI/1, refractory produc
5、ts and materials, to Subcommittee RPI/1/1, Sampling and physical testing of refractory materials, which has the responsibility to: aid enquirers to understand the text; present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interes
6、ts informed; monitor related international and European developments and promulgate them in the UK. The UK did not approve this document as a European Standard at the Formal vote stage. The Subcommittee RPI/1/1 decided that it contained fundamental flaws in the instructions for recording the output
7、of the differential thermocouple. A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalog
8、ue under the section entitled International Standards Correspondence Index, or by using the Find facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct
9、 application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 10, an inside back cover and a back cover. Licensed Copy: sheffieldun sheffieldun,
10、na, Tue Nov 07 06:16:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI CEN European Committee for Standardization Comite Europe en de Normalisation Europa isches Komitee fu r Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1998 CEN All rights of exploitation in any form and by any means
11、 reserved worldwide for CEN national Members. Ref. No. EN 993-15:1998 E EUROPEAN STANDARDEN 993-15 NORME EUROPE ENNE EUROPA ISCHE NORM April 1998 ICS 81.080 Descriptors: Refractory materials, shaped refractories, dense shaped refractory products, powdery materials, tests, determination, thermal cond
12、uctivity, test specimen, procedures English version Methods of test for dense shaped refractory products Part15: Determination of thermal conductivity by the hot-wire (parallel) method Me thodes dessai pour produits re fractaires faonne s denses Partie 15: De termination de la conductivite thermique
13、 par la me thode du fil chaud (paralle le) Pru fverfahren fu r dichte geformte feuerfeste Erzeugnisse Teil 15: Bestimmung der Wa rmeleitfa higkeit nach dem Heidraht-(Parallel-)Verfahren This European Standard was approved by CEN on 23 March 1998. CEN members are bound to comply with the CEN/CENELEC
14、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 any CEN m
15、ember. 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 and notified to the Central Secretariat has the same status as the official versions. CEN memb
16、ers are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 07 06:16:27 GMT
17、+00:00 2006, Uncontrolled Copy, (c) BSI Page 2 EN 993-15:1998 BSI 1998 Foreword This European Standard has been prepared by Technical Committee CEN/TC 187, Refractory products and materials, the secretariat of which is held by BSI. This European Standard shall be given the status of a national stand
18、ard, either by publication of an identical text or by endorsement, at the latest by October 1998, and conflicting national standards shall be withdrawn at the latest by October 1998. It is closely based on the corresponding International Standard, ISO 8894-2 Refractory materials Determination of the
19、rmal conductivity Part 2: Hot-wire method (parallel), published by the International Organization for Standardization (ISO). The determination of thermal conductivity by the hot-wire (cross-array) method is given in EN 993-14. Reproducibility and repeatability data are not available, but may be give
20、n in a subsequent edition. EN 993 Methods of test for dense shaped refractory products consists of 18 parts: 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: Determinati
21、on of permeability to gases; Part 5: Determination of cold crushing strength; Part 6: Determination of modulus of rupture, ambient temperatures; Part 7: Determination of modulus of rupture, elevated temperatures; Part 8: Determination of refractoriness-under-load; Part 9: Determination of creep in c
22、ompression; Part 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; Part 13: Specification of pyrometric cones; Part 14: Determination of thermal conductivity by the hot wi
23、re (cross-array) method; Part 15: Determination of thermal conductivity by the hot wire (parallel) method; Part 16: Determination of resistance to acids; Part 17: Determination of bulk density of granular material (mercury method); Part 18: Determination of bulk density of granular material (water m
24、ethod). According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Nor
25、way, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Contents Page Foreword2 1Scope3 2Normative references3 3Definitions3 4Principle3 5Apparatus3 6Test pieces6 7Procedure6 8Assessment of results7 9Expression of results8 10Test report8 Annex A (informative) Example of the determination o
26、f thermal conductivity10 Annex B (informative) Bibliography10 Licensed Copy: sheffieldun sheffieldun, na, Tue Nov 07 06:16:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 3 EN 993-15:1998 BSI 1998 1 Scope This part of EN 993 specifies a hot-wire (parallel) method for the determination of thermal
27、conductivity of refractory products and materials. It is applicable to dense and insulating shaped products and to powdered or granular materials (see 7.2), for thermal conductivities of less than 25 W/mK. The limits are imposed by the dimensions of the test pieces and higher thermal conductivities
28、can be measured if larger pieces are used. Electrically conducting materials cannot be measured. NOTE 1The thermal conductivity of bonded bricks 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 req
29、uire pre-treatment; 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 part of EN 993 and should be agreed between the parties concerned.
30、 NOTE 2In general 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 Normative references This European Standard incorporates by dated or undated references, provisions from other publicat
31、ions. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision.
32、For undated references the latest edition of the publication referred to applies. EN 993-14, Methods of test for dense shaped refractory products Determination of thermal conductivity by the hot wire (cross-array) method. ISO 31-4, Specification for quantities, units and symbols. Heat. 3 Definitions
33、 For the purposes of this standard, the following definitions, in accordance with EN 993-14, and ISO 31-4 apply: 3.1 thermal conductivity, l density of heat flow rate divided by the temperature gradient, in units of watt per metre kelvin (W/mK) 3.2 thermal diffusivity, a a = l r.Cp where: lis the th
34、ermal conductivity; ris the bulk density; Cpis the specific heat capacity at constant pressure thermal diffusivity is expressed in units of square metre per second (m2.s21) 3.3 power, P rate of energy transfer, in units of watts (W) 4 Principle The hot-wire method (parallel) is a dynamic measuring p
35、rocedure based on the determination of the temperature increase against time at a certain location and at a specified distance from a linear heat source embedded between two test pieces. The test pieces are heated in a furnace to a specified temperature and maintained at that temperature. Further lo
36、cal heating is provided by a linear electrical conductor (the hot wire) that is embedded in the test piece and carries an electrical 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 thermoc
37、ouple leads running parallel to the wire (see Figure 1). The increase in temperature as a function of time, measured from the moment the heating current is switched on, is a measure of the thermal conductivity of the material from which the test pieces are made. 5 Apparatus 5.1 Furnace, electrically
38、 heated, capable of taking one or more test assemblies (see 6.1) up to a maximum temperature of 1 250 8C. The temperature at any two points in the region occupied by the test pieces shall not differ by more than 10 8C. The temperature measured on the outside of the test assembly during a test (of du
39、ration about 15 min) shall not vary by more than0,5 8C, and shall be known with an accuracy of5 8C. 5.2 Hot wire, preferably of platinum or platinum-rhodium, about 200 mm in length and not exceeding 0,5 mm in diameter, the actual length being known to within0,5 mm. NOTEA hot wire made of base metal
40、can be used at temperatures below 1 000 8C. Both ends of the hot wire are attached to the power source and the digital multimeter (see 5.5). 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
41、the digital multimeter shall be of a diameter not greater than that of the hot wire when within the assembly. 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 with heavy gauge cable. 5
42、.3 Power supply, to the hot wire (see 5.2), which shall be stabilized a.c. or d.c. and shall not vary in power by more than 2 % during the period of measurement. A supply to the hot wire of at least 80 W is required. NOTEThis is equivalent to 400 W/m for a 200 mm long wire. Licensed Copy: sheffieldu
43、n sheffieldun, na, Tue Nov 07 06:16:27 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 4 EN 993-15:1998 BSI 1998 1 2 3 4 5 6 7 Cover Reference thermocouple Optional insulating layer Measurement thermocouple Measurement circuit Heating circuit Voltage taps Figure 1 Location of heating circuit and mea
44、surement circuit (differential thermocouple circuit) 5.4 Differential platinum/platinum-rhodium thermocouple, (Type R: platinum 13 % rhodium/platinum thermocouple or Type S: platinum 10 % rhodium/platinum thermocouple, see Table 1) formed from a measurement thermocouple and a reference thermocouple
45、connected in opposition (see Figure 1). The leads of the measurement thermocouple shall run parallel to the hot wire at a distance of 15 mm1 mm (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 o
46、f the same material as the test piece (see Figure 1). The diameter of the thermocouple wires shall be the same as that of the hot wire and the thermocouple wires shall be long enough to extend outside the furnace where connections to the measuring apparatus shall be made by wire of a different type.
47、 The external connections of the thermocouple shall be isothermal. NOTE 1An insulating layer can be inserted between the cover and the upper test piece. NOTE 2Base metal thermocouples can be used at temperatures below 1 000 8C. 5.5 Digital multimeter, for measuring the current in the hot wire and th
48、e voltage drop across it, and capable of measuring both to an accuracy of at least0,5 %. 5.6 Data acquisition system, consisting of a temperature-time registration device with a sensitivity of at least 2 mV/cm or 0,05 mV/Digit, or a temperature measurement of 0,05 8C with a time resolution better th
49、an 0,5 s. 5.7 Containers, (for use if the test is performed on powdered or granular material), having internal dimensions equal to those of the solid test assembly specified in clause 6, so that the test assembly shall consist of two sections as specified in 6.1. 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). NOTEContainers should be of a material that will not react with the test piece at the tempe