BS 3183-1968 Method for the determination of wool fibre diameter by the airflow method《用气流法测定羊毛纤维直径的方法》.pdf

1、BRITISH STANDARD BS 3183:1968 Method for The determination of wool fibre diameter by the airflow methodBS3183:1968 This British Standard, having been approved by the Textile Divisional Council, was publishedunder the authority ofthe General Council on 16October1968 BSI 08-1999 First published Decemb

2、er 1959 First revision October 1968 The following BSI references relate to the work on this standard: Committee reference T/-/8 Draft for comment 67/15783 ISBN 580 00362 0 Co-operating organizations The Textile Divisional Council, under whose supervision this British Standard was prepared, consists

3、of representatives from the following Government department and scientific and industrial organizations: British Railways Board Consumer Council Cotton Industry Standards Committee Jute Industry Standards Committee Linen Industry Standards Committee London Transport Board Man-made Fibres Industry St

4、andards Committee Ministry of Defence Ropes and Cordage Industry Standards Committee Silk Industry Standards Committee Society of Dyers and Colourists* Textile Institute* Textile Machinery Industry Standards Committee Trades Union Congress Wool Industry Standards Committee The organizations marked w

5、ith an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: British Jute Trade Research Association British Man-made Fibres Federation Committee of Directors of Textile Research Associations Commo

6、nwealth Joint Services Committee Cotton Silk and Man-made Fibres Research Association Hosiery and Allied Trades Research Association International Federation of Cotton and Allied Textile Industries Linen Industry Research Association Amendments issued since publication Amd. No. Date of issue Comment

7、sBS3183:1968 BSI 08-1999 i Contents Page Co-operating organizations Inside front cover Foreword ii 1 Scope 1 2 Principle 1 3 Apparatus 1 4 Conditioning and testing atmosphere 1 5 Test specimen 1 6 Test procedure 1 7 Calculation and expression of results 1 8 Report 2 Appendix A Construction and calib

8、ration of two forms of apparatus in general use 3 Figure 1 General arrangement of the apparatus 4 Figure 2 Section through the constant-volume chamber 5BS3183:1968 ii BSI 08-1999 Foreword This standard makes reference to the following British Standards: BS 1051, Terms relating to the conditioning of

9、 textiles and method for the determination of correct invoice weight. BS 2043, Method for the determination of wool fibre fineness by the use of a projection microscope. This British Standard has been published by arrangement between the Textile Institute and the British Standards Institution. It wa

10、s originally based on Tentative Textile Standard No.51, which appeared in the Journal of the Textile Institute for July,1958. In the present revision all dimensions are in metric units, and certain other changes have been made to bring the method into line with current practice. There is a close cor

11、relation between the air-permeability of a uniformly distributed mass of textile fibres and the specific surface area of the fibres. It is therefore possible to use air-permeability as a quick estimate of fibre fineness. For fibres of approximately circular cross section and constant overall density

12、, such as unmedullated wool, the estimate of fineness gives the average fibre diameter, as determined by the projection microscope, with a good degree of accuracy. The procedure described is in full conformity with Draft ISO Recommendation No.1245, “Permeability method for measuring the mean diamete

13、r of wool fibres”. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This

14、document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS3183:1

15、968 BSI 08-1999 1 1 Scope This British Standard deals with the determination of fibre diameter of wool slivers. The method is also applicable to clean wool noils. It is not suitable for samples of wool that have not been opened and cleaned. 2 Principle A test specimen of fixed weight of fibre is com

16、pressed to a fixed volume in an air permeameter. A current of air is drawn through the specimen and the fibre diameter of the specimen is obtained from the flowmeter or manometer of the permeameter. 3 Apparatus 3.1 Air permeameter comprising: 1) Constant-volume chamber, with perforated ends, of such

17、 a size as to give an overall density of packing between0.20g/cm 3and0.36g/cm 3with the prescribed specimen weight. 2) Means for effectively measuring the air flow and pressure difference across the specimen packed in the constant-volume chamber. 3.2 Suction pump for drawing air through the specimen

18、. 3.3 Balance for weighing the test specimen to an accuracy of 0.2%. 3.4 Means for producing an atmosphere for testing as defined inClause 4. Details of the construction and calibration of two different forms of apparatus which fulfil these requirements are given inAppendix A. 4 Conditioning and tes

19、ting atmosphere The conditioning and testing atmosphere shall be the standard atmosphere for testing textiles defined in BS1051 1) , i.e.,a relative humidity of652% and a temperature of20 2 C. 5 Test specimen 5.1 Conditioning. The laboratory sample shall be conditioned for at least4h in an open stat

20、e, in a well-ventilated place in the standard atmosphere for testing. Noils shall be conditioned after cleaning as described in5.5. 5.2 Weight of specimen. The weight of the test specimen shall be that for which the instrument has been calibrated, but shall be between1.4g and2.6g. 5.3 Number of spec

21、imens. A minimum of four test specimens for wool of more than30microns fibre diameter and three test specimens for wool of30 microns fibre diameter or finer are tested. 5.4 Preparation of specimen. From a sliver with cut ends, cut off with scissors a length to give as nearly as possible the correct

22、specimen weight, then make up to the exact weight by adding cut lengths from a second section of sliver. Discard any non-wool material before weighing. 5.5 Noil. Take small amounts of fibre from several places in the laboratory sample to make up a total of about9g. Clean the sample by giving it two

23、rinses in light petroleum or carbon tetrachloride, and then condition it in the standard atmosphere for testing textiles. Mix the fibres together and divide into three parts. From each of these parts, take several pinches of fibre, discarding any non-wool material, and make up to the required specim

24、en weight. Two further specimens may be made up if required from the remaining portion of the original9g. 6 Test procedure 6.1 Ensure that the instrument is level and that any controls, dials, or liquid levels are set in the zero position. 6.2 Pack the weighed specimen evenly into the constant-volum

25、e chamber, a small amount at a time, pushing the fibres down with a smooth rod approximately12mm in diameter. Then push on the perforated top of the constant-volume chamber and screw down the retaining cap. 6.3 Switch on the air supply, adjust the controls of the instrument to the prescribed setting

26、s and read the manometer or flowmeter to the nearest1mm. 6.4 Take out the specimen and reverse its direction, then repack it in the constant-volume chamber and take another reading. Repeat this until four readings have been made. 6.5 Repeat the procedure using the remaining specimens. 7 Calculation

27、and expression of results Calculate and record the average of the16or12 readings and read off and record the average fibre diameter from the calibration table to the nearest0.1micron. 1) BS1051, “Terms relating to the conditioning of textiles and method for the determination of correct invoice weigh

28、t.”BS3183:1968 2 BSI 08-1999 8 Report The report shall state the following: 1) That the method was performed in accordance with this method of test. 2) The number of specimens used. 3) The average of the readings taken. 4) The average fibre diameter.BS3183:1968 BSI 08-1999 3 Appendix A Construction

29、and calibration of two forms of apparatus in general use A.1 Introduction Of the alternative forms of apparatus described, that for Method I uses less fibre, operates at constant flow and is primarily a laboratory instrument. Method II uses a larger weight of fibre, consequently needing less accurac

30、y in weighing, has a nearly linear scale, operates at constant air pressure and is on the whole more suitable for mill use. The component parts of both forms of apparatus have been chosen from those generally available commercially so that, except for the constant-volume chamber, they can be constru

31、cted and calibrated within a laboratory. A.2 Detailed description of the parts The parts required are as follows and their arrangement is shown inFigure 1. 1) Constant-volume chamber A in brass made to dimensions given inFigure 2. 2) Needle valve B giving fine control of the air supply. 3) A manomet

32、er reservoir D, which is an aspirator bottle of diameter at least150mm and mounted at sufficient height to give a clear working distance ZH of350mm in the glass limb. The bend C should be made of glass tube of internal diameter approximately5mm. The manometer is filled up to the indicated level with

33、 (MethodI)propyl alcohol; (MethodII) distilled water. In both cases, a small amount of dye may be added, and to the distilled water should be added a small amount of chromic acid to give a clear meniscus. The base of the stand on which the manometer is mounted has three levelling screws fitted. 4) F

34、lowmeter F covering the range (MethodI)1020litres/min; (MethodII)3.523.5litres/min. The suction pump, which, is not shown, is a high-speed type providing a smooth output and little fluctuation of the float of the flowmeter. If the noise from the pump is excessive, the pump may be mounted some distan

35、ce away from the apparatus, even outside the room. The rubber tube connecting the manometer D to the chamber A is pressure tubing of small internal diameter to avoid constriction at the bend. The short tube from A to the flowmeter F is of internal diameter not less than6mm and should not be twisted

36、or displaced between calibration of the apparatus and its subsequent use. This avoids changes in the air-resistance of the apparatus. A.3 Calibration A.3.1 Leakage test. After assembling the apparatus as inFigure 1, remove the screw cap and perforated top from the constant-volume chamber A and inser

37、t a rubber stopper. By means of a Hoffman clip, close the rubber tube between A and F after inducing a pressure difference, causing the meniscus in the manometer to alter by about150mm. Note the position of the meniscus periodically for several minutes. If it changes, the apparatus should be examine

38、d for leaks. A.3.2 Samples of sliver. About15g of each of14or more wool slivers are required with fibre diameters covering a range of1840microns at nearly equal intervals. These slivers should be measured for fibre diameter by the projection microscope strictly according to BS2043 2) , the measureme

39、nts preferably being made by more than one observer. The lengths of sliver should be previously cleaned by giving two rinses in light petroleum or carbon tetrachloride and then conditioned at65% relative humidity and20 C before test 3) . A.3.3 Graduating the scale A.3.3.1 Method I. Mark a horizontal

40、 mark Y (Figure 1) near the top of the flowmeter scale. Fix a millimetre scale behind the right-hand limb of the manometer and adjust the zero mark to coincide with the meniscus of the liquid (with the pump switched off). Then take1.5g specimens of sliver and test according to the procedure describe

41、d inClause 6, noting the distance in millimetres to which the meniscus falls below zero. 2) BS2043, “Method for the determination of wool fibre fineness, by the use of a projection microscope”. 3) If tests are regularly carried out on oil-combed slivers, calibration may also be carried out without c

42、leaning and a separate scale may be graduated relating to oil-combed slivers only.BS3183:1968 4 BSI 08-1999 Plot the logarithm of depression against logarithm of mean fibre diameter which should produce a nearly linear relation. Fit a regression equation to these data by the method of least squares.

43、 From this equation a table is prepared relating the scale reading in millimetres to average fibre diameter in microns. A.3.3.2 Method II. Make a horizontal mark at a distance of180mm below the zero mark Z of the manometer. Fix a millimetre scale behind the flowmeter F so that the zero of this scale

44、 coincides with a scratch made near the bottom of the flowmeter. Then take2.5g specimens of sliver and test as described in Clause 6, noting the distance in millimetres of the float of the flowmeter from zero for each sample. Make a plot of mean distance in millimetres against mean diameter measured

45、 by the projection microscope and after inspection to verify that the points lie about a line, fit a second degree regression equation by the method of least squares (a second degree equation is necessary since the relation between distance and diameter is not in general a straight line). From this

46、equation a table is prepared relating the scale reading in millimetres to Figure 1 General arrangement of the apparatusBS3183:1968 BSI 08-1999 5 Figure 2 Section through the constant-volume chamber6 blankBS3183:1968 BSI 08-1999 British Standards The following are available on application: YEARBOOK I

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