1、 CEN ENx773-4 95 3404589 O096480 602 1 :3? 1995 BRITISH STANDARD Methods of test for Dense shaped refractory products Part 4. Determination of permeability to gases The European Standard EN 993-4 : 1995 has the status of a British Standard BS 1902 : Section 3.9 : 1995 CEN EN*993-4 95 H 3404589 00964
2、81 549 BS EN 993-4 : 1995 Standards Board and comes into effect on 15 May 1995 0 BSI 1995 Amd. No. Cooperating organizations Date Text affected The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organization
3、s of the following countries: Austria Belgium Denmark Finland France Germany Greece Iceland Ireland Italy Luxembourg Netherlands Norway Portugal Spain Sweden Switzerland United Kingdom Oesterreichisches Normungsinstitut Institut belge de normalisation Dansk Standard Suomen Standardisoimisliito, r. y
4、. Association francaise de normalisation Deutsches Institut fr Normung e.V. Hellenic Organization for Standardization Technological Institute of Iceland National Standards Authority of Ireland Ente Nazionale Italiano di Unificazione Inspection du Travail et des Mines Nederlands Normalisatie-instituu
5、t Norges Standardiseringsforbund Instituto Portugus da Qualidade Asociacin Espaola de Normalizacin y Certificacin Standardiseringskommissionen i Sverige Association suisse de normalisation British Standards Institution The following BSI references relate to the work on this standard: Committee refer
6、ence RPM/1 Draft for comment 93/303889 DC ISBN O 580 23605 6 BS EN 993-4 : 1995 Contents Page Cooperating organizations Inside front cover National foreword Foreword 2 %xt of EN 993-4 3 National annex NA (informative) Committees responsible Inside back cover National foreword This British Standard h
7、as been prepared under the direction of the Refractory Products Standards Policy Committee and is the English language version of EN 993-4 : 1995 Methods of test for dense shaped refractory products - Part 4 : Determination of permeability to gases, published by the European Committee for Standardiz
8、ation (CEN). It supersedes BS 1902 : Section 3.9 : 1981 which is withdrawn. EN 993-4 was produced as a result of international discussions in which the UK took an active part. Compliance with a British Standard does not of itself confer immunity from legal obligations. i CEN EN*993-4 95 3404589 0096
9、483 311 m EUROPEAN STANDARD EN 993-4 NORME EUROPENNE EUROPISCHE NORM February 1995 ICs 81.080 Descriptors: Refractory materials, shaped refractories, dense shaped refractory products, tests, measurements, gas permeability English version Methods of test for dense shaped refractory products - Part 4:
10、 Determination of permeability to gases Mthodes dessai pour produits rfractaires faconns denses - Erzeugnisse - Partie 4: Dtermination de la permabilit aux gaz Prfverfahren fr dichte geformte feuerfeste Teil 4: Bestimmung der Gasdurchlssigkeit This European Standard was approved by CEN on 1995-02-15
11、. CEN 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 such national standards may be obtained on
12、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 and notified to the Central Secretariat
13、has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for St
14、andardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels O 1995 Copyright reserved to CEN members Ref. No. EN 993-4 : 1995 E Page 2 EN 993-4 : 1995 Foreword This European Standard has been prepared by the Technical Committee
15、 CEN/TC 187, Refractory products and materials, the secretariat of which is held by BSI. It is closely based on the corresponding International Standard IS0 8841 : 1991 Dense, shaped refractory products - Determination of permeability to gases, published by the International Organization for Standar
16、dization Reproducibility and repeatability are not available, but may be given 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 P
17、art 3: %st methods for carbon-containing ref rac tories Part 4: Determination of permeability 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: Deter
18、mination of refractoriness-under-load Part 9: Determination of creep in compression Part 10: Determination of permanent change in dimensions on heating Part 11: Determination of resistance to thermal shock Part 12: Determination of pyrometric cone equivalent Part 13: Specification for pyrometric con
19、es Part 14: Determination of thermal conductivity (hot wire, cross-array) Part 15: Determination of thermal conductivity (hot wire, parallel) Part 16: Determination of resistance to acids Part 17: Determination of bulk density of granular material (mercury method) Part 18: Determination of bulk dens
20、ity of granular material (water method) 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 August 1995, and conflicting national standards shall be withdrawn at the latest by August 1995. According t
21、o the CENXENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom. (ISO) . Contents
22、Foreword 1 Scope 2 Normative reference 3 Definition 4 Principle 5 Apparatus 6 Test pieces 7 Procedure 8 Expression of results 9 %streport Page 2 3 3 3 4 4 4 5 6 7 Page 3 EN 993-4 : 1995 Dense, shaped refractory products - Determination of permeability to gases 1 Scope This European Standard specifie
23、s a method for the measurement of the permeability to gases of dense, shaped refractory products. NOTE 1 The method specified takes account of the dy- namic viscosity of the gas, and therefore the results ob- tained may not be directly comparable with those obtained by earlieio methods which took no
24、 account of viscosity. The determination is generally made by the passage of air. Other gases may be used when required, and the visc6sities of air and nitrogen are given. 2 Normative reference This European Standard incorporates by dated or undated reference, provisions from anather publication. Th
25、is normative reference is cited at the appropriate places in the text and the publication is listed hereafter. For a dated reference, subsequent amendments to or revisions of this publication apply to this European Standard only when incorporated in it by amendment or revision. For an undated refere
26、nce the latest edition of the publication referred to applies. IS0 6906:1984, Vernier callipers reading lo QU2 mm. 3 Deflnltion For the purposes of this European Standard, the following definition applies. 3.1 permeability a a material: The property by which the material allows a gas to pass through
27、 it when under a difference of pressure. The permeability (p) is calculated using the follow- ing equation, given for the volume of gas passing through a test piece in a given time: where V I It v A d P P1 P2 NOTES is the votume of gas passing through the material, in cubic metres; is the time, in s
28、econds, in which that vol- ume of gas passes through the material; is the permeability of the material. in square metres; is the dynamic viscosity, in paseal sec- onds, of the gas at the temperature of the test; is the cross-sectional area, in square metres, of the material traversed: is the thickne
29、ss, in metres, of the ma- terial traversed; is the absolute pressure, in pascals, of the gas; is the absolute pressure, in pascals, where the gas enters the material; is the absolute pressure, in pascals, where the gas leaves the material. 1 duced from the Hagen Poiseuille Law. 2 Since p is the pres
30、sure under which the volume of gas is measured, p = pi when operating under positive pressure, and p = p2 when operating under negative pressure. 3 The factor (jq + p2)/2p is usually very close to unity and may be neglected when operating with small pressure differences, e.g. when 01, - p2) is less
31、than 1 O00 Pa. Equation (I) corresponds to Darcys Law, and is de- CEN EN*993-4 95 D 3404589 0096486 020 D Page 4 EN 993-4 : 1995 Equation (I) may be rearranged as Writing equation (2) in the units involved, the unit for permeability is square metres, derived from if, in equation (l), 6 is expressed
32、in centimetres, R in square centimetres and I/ in cubic centimetres (the units for the other quantities being unchanged), an alternative unit for permeability may be derived, namely square centimetres. However. since com- pound prefixes are not permissible, the conventional prefixes may be used only
33、 with the unit square me- tres, thus IO-* cm2= 10-I2m2 = lpm. 4 Prlnciple A stream of dry gas is passed through the test piece, and the pressure drop across the test piece is re- corded for at least three different rates of flow. From Ihese values, and from the size and shape of the lest piece, the
34、permeability of the material is determined by calculation. 5 Apparatus 5.1 General The general layout of the apparatus is shown diagramatically in figures 1 and 2. Figurei shows the arrangement for the passage of gas under pressure and figure2 for the passage of gas under suction. The connecting pip
35、ing shall be made of glass in preference to rubber, and shall be as short as possible, so that the pressure loss in the appa- ratus is very small when compared with the press- ure loss produced by the test piece. 5.1.1 Supply of gas (under pressure or suction). consisting of a reservoir of gas at co
36、nstant pressure. 5.1.2 Test piece holder, with gas-tight seals at the sides of the test piece. Gas tightness shall be en- sured by a rubber membrane that is inflated to a pressure of 0.2 N/mrn2 to 0,4 N/mm2. See figure 3. NOTE. test piece size (see note to 6.1) is used. Modifications will be require
37、d if the alternative 5.1.3 Liquid manometer, of the U-tube type, for measuring the difference in pressure between the two faces of the test piece. The usual experimental precautions for this type of measurement shall be taken, so that the error in the pressure deterrni- nation does not exceed 1 (inc
38、luding error in reading column height, meniscus error, error in the verticality of the manometer, and measurement of the density of the manometer liquid). The pressure shall be determined close to one face of the test piece in the vessel containing the test piece holder (5.1.2). NOTE. A lower pressu
39、re reading may result when the pressure away from the test piece is determined in the connecting tubes. 5.1.4 Gas flow measuring equipment, consisting of a sensitive floating flowmeter calibrated for a given temperature and pressure of entry. The flowmeter shall be accurate to within 2 %. The flowme
40、ter shall be calibrated periodically for the gas to be used, and only the middle section of its measuring scale shall be used. For lhe measurement of permeability to air only, the rate of air flow is measured by the displacement of air by water, using a graduated cylinder device and a chronometer. W
41、ater sensitive materials, such as doloma, shall not be measured by the method in which air flow is obtained by the displacement of water. 5.1.5 Vernier callipers, in accordance with IS0 6906. 5.1.6 Drying oven, capable of being controlled at 1 10 OC -t: 5 OC. 5.1.7 Impermeable dummy test piece, for
42、example an aluminium cylinder. 6 Test pieces 6.1 Dimensions The test pieces shall be cylindrical, with diameter 50 mm the time of cooling shall be at least 2 h. 1 Source of gas (compressed gas cylinder or water reservoir) 2 Desiccator for the gas 3 Floating flowmeters: ta) O to 200 cm3/min, (b) ax)
43、cm3/min to 1 5oO cm3/min 4 Holder for cylindrical sample 5 U-tube manometer, filled with liquid Figure 1 - Arrangement of instruments for measuring gas permeability (measured under a pressure head) 6 KEY Ya -_ 3 1 Entry of the gas, via a desiccator 2 Holde: for cylindrical sample 3 U-tube manometer
44、filled with liquid 4 Floating flowmeters: (al O to 200 cm3/min, b) 200 cm3/min to 1 !i cmJ/rnin 5 Woulff safety bottles 6 Regulating vent 7 Diaphragm or water pump Figure 2 - Arrangement of instruments for measuring gas permeability (measurd under suction) measurement Forp-ure JT 7 Figure 3 - Test p
45、iece holder 7 Procedure 7.1 Carry out a blank determination to establish that the test rig is gas-tight using an impermeable dummy test piece (5.1.7) in the pface of the normal test piece. 7.2 Measure the diameter and the height o the test piece to 0,l mm, using the Vernier callipers (5.1 -5). 7.3 P
46、lace the test piece in the holder (5.1.2), en- suring that the pressure on the rubber membrane is sufficient to render the cylindrical surface of the test piece gas-tight. This may be checked by increasing the pressure on the membrane; there should be no change in the pressure difference between the
47、 plane faces and no change in the rate of gas flow. 7.4 Determine the rate of flow through the test piece for at least three different pressure drops across it. Calculate the permeability of the test piece for each determination. (See clause 8.) NOTE. These determinations are to verify that the rate
48、 of flow is proportional to the pressure drop, because the equation used for the calculation (see clause 8) is only valid for laminar flow. CEN EN*993-4 95 3404589 0096488 9T3 16 18 20 22 24 Page 6 EN 993-4 : 1995 17,88 0.982 17,98 0.980 18.08 0.91 1 18,18 0,914 18,28 0,971 7.5 If the calculated per
49、meabilities at the three different pressure drops differ among themselves by more than 5 %, repeat the blank test, check the equipment and repeat the tests. If the repeat tests still differ by more than 5 %, state this in the test report. 8 Expression of results 8.1 to two significant digits, is given by the equation The permeability. expressed in square metres . . . (3) where t /I A AP 4v 4 NOTE. is the dynamic viscosity, in pascal sec- onds), of the gas passed through the test piece at the temperature of the test; is the height, in metres, o
