ISO-2648-1974.pdf
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1、INTERNATIONAL ORGANIZATION FOR STANDARDIZATION .MEXPYHAPOLlHAA OPrAHMSAUMII no CTAHLIAPTMSAUMM -ORGANISATION INTERNATIONALE DE NORMALISATION Laine - Dtermination des paramtres de distribution de longueur des fibres - Mthode lectronique - u z UD6 677.31/33 : 531.71 : 621.317.33 Ref. No. IS0 2648-4974
2、 (E) Descriptors : fibres, animal fibres, wool, tests, dimensional measurement, length, electronic method, test specimen conditioning, test 3 equipment. a (u , Price based on 19 pages Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Techni
3、cal Standards 1/9972545001 Not for Resale, 04/19/2007 06:24:31 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 (the International Organization for Standardization) is a worldwide federation of national standards institutes (IS0 Member Bodies). The work of developing Int
4、ernational Standards is carried out through IS0 Technical Committees. Every Member Body interested in a subject for which a Technical Committee has been set up has the right to be represented on that Committee. International organizations, governmental and non-governmental, in liaison with ISO, also
5、 take part in the work. Draft International Standards adopted by the Technical Committees are circulated to the Member Bodies for approval before their acceptance as International Standards by the IS0 Council. International Standard IS0 2648 was drawn up by Technical Committee ISO/TC 38, Textiles an
6、d circulated to the Member Bodies in July 1972. It has been approved by the Member Bodies of the following countries : Austria Belgium Bulgaria Canada Czechoslovakia Denmark Egypt, Arab Rep. of Finland Germany Hungary India I ran Ireland Israel Japan Mexico New Zealand Poland Portugal Roman ia South
7、 Africa, Rep. of Spain Sweden Switzerland Thailand Turkey United Kingdom U.S.A. U.S.S.R. The Member Body of the following country expressed disapproval of the document on technical grounds : France This International Standard is based on the IWTO test method 17-67, drawn up by the International Wool
8、 Secretariat (IWS). Three successive interlaboratory tests have enabled the progressive development of the standard test method and the control and calibration method described in this International Standard. The favourable results of the last two experiments led to the adoption of the standard meth
9、od of test and the calibration and control methods using a series of plastic calibrators, specially prepared for the participants in these experiments. 0 International fganization for Standardization, 4974 o Printed in Switzerland Copyright International Organization for Standardization Provided by
10、IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/19/2007 06:24:31 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD IS0 2648-1974 (E) 1 SCOPE AND FIELD OF APPLlCAflBN This International Standard specifies a me
11、thod for the determination of fibre length distribution parameters, principally mean length and the coefficient of variation of length, for all-wool slivers and rovings. The method is not directly applicable to slivers made up of a blend of two or more fibres. Selection of the test specimen is effec
12、ted using an auxiliary machine, called “mechanical grip“; it may be used on top sliver, on worsted drawing slivers and rovings, and on slivers from the semi-worsted system. 2 PRINCIPLE AND DEFINITION OF THE TEST PARAMETERS 2.1 Principle The electronic machine tests the length of textile fibres, usin
13、g a specimen of fibres made up with the aid of the mechanical grip. This grip, fed with slivers or rovings, prepares-a numerical specimen of fibres, .e. one in which the number of fibres in each length class are represented in the same proportion as in the original sliver. This specimen is in the fo
14、rm of a draw of parallel fibres, all these fibres having their ends approximately on a line perpendicular to the direction of the fibres. The specimen formed in this way is then transferred from the grip to an electronic instrument, where it is placed in a slide between two thin plastic sheets. The
15、slide containing the test specimen moves at constant speed, through a measuring condenser. The variation in capacity caused in this way (due to the partial replacement of the “air“ dielectric by the “wool“ dielectric) is proportional to the mass of the portion of the draw of fibres situated in the c
16、ondenser. In view of the constitution of the specimen, it is easily shown that the record of changes in the signal proportional to the changes in capacity is equivalent to a diagram of “hauteur“ /-/ (see references 1 and 2, annex A). This diagram is automatically traced by a recorder connected to th
17、e main machine. _ . 2.2 Pest parameters An electronic calculator that is incorporated automatically evaluates the following length distribution parameters during test : 1) mean cross-section biased length or hauteur H : (a, 1) in Palmers notation; 2) coefficient of variation of hauteur, CVH; 3) mean
18、 length X cross-section biased length, or barbe B : (a/, 1) in Palmers notation. As the density of the fibres may be regarded as constant, the barbe B is also the mean weight biased : (w, 1) in Palmers notation. 3 APPARATUS The apparatus comprises three parts : 1) the mechanical grip; 2) the main el
19、ectronic instrument; 3) the recorder. A suitable machine is described in annex C. 3.1 The mechanical grip The grip works in the same way as the nip of a rectilinear comb. With each movement it extracts from the sliver a numerical sample containing all the fibres having their ends within a short leng
20、th of the sliver, between two cross-sections perpendicular to the sliver axis about 2,5 to 3,7 mm apart. The complete specimen is made up of a collection of about ten to sixteen of these samples. 3.2 The main electronic instrument The main electronic instrument consists of two parts : 1) a device fo
21、r measuring the local mass of the fibre specimen, and 2) a calculator, automatically evaluating the length distribution parameters during the test. 1 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for
22、 Resale, 04/19/2007 06:24:31 MDTNo reproduction or networking permitted without license from IHS -,-,- 2648-74 3.3 The recorder A galvanometric or potentiometric recorder automatically traces the cumulative diagram of hauteur on squared paper during the test (see figure 1). The diagram ordinate give
23、s the percentage (linear density biased) of fibres, the length of which is greater than the length shown by the corresponding abscissa. (The linear density biased percentage is very near to the numerical percentage.) The lengths in abscissa are actual lengths (scale 1/11. 4 TEST SPECIMENS 4.1 In the
24、 case of wool top slivers, the mass of which is between 15 and 30 g/m, a length of 1,20m of sliver is broken off from the ball or bump top, Immediately after drawing this sample, it is held under slight tension and given 24 turns of twist; held taut in this state, it is then gripped a t its centre,
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