BS 3181-1-1987 Methods for determination of cotton fibre properties by the airflow method - Determination of micronaire value by the single compression airflow method《气流法测定棉纤维性能 第1.pdf

1、BRITISH STANDARD BS 3181-1: 1987 Methods for Determination of cotton fibre properties by the airflow method Part 1: Determination of micronaire value by the single compression airflow method UDC 677.1.03.21:620.168.35 + 677.017.622:620.173BS3181-1:1987 This British Standard, having been prepared und

2、er the directionof the Textiles and Clothing Standards Committee,was published underthe authorityof the BoardofBSI and comes intoeffecton 30 November 1987 BSI 12-1999 First published December 1959 First revision April 1968 Second revision as Part 1 November 1987 The following BSI references relate t

3、o the work on this standard: Committee reference TCM/24 Draft for comment 86/43657 DC ISBN 0 580 16268 0 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Textiles and Clothing Standards Committee (TCM/-) to Technical Committee TCM/24, upo

4、n which the following bodies were represented: Association of Consulting Scientists British Polyolefin Textiles Association British Textile Employers Association International Wool Secretariat Man-made Fibres Producers Committee Ministry of Defence SATRA Footwear Technology Centre Soap and Detergent

5、 Industry Association Society of Dyers and Colourists Society of Motor Manufacturers and Traders Limited Textile Institute Textile Research Council Amendments issued since publication Amd. No. Date of issue CommentsBS3181-1:1987 BSI 12-1999 i Contents Page Committees responsible Inside front cover F

6、oreword ii 1 Scope 1 2 Principle 1 3 Apparatus 1 4 Atmosphere for conditioning and testing 1 5 Test specimens 1 6 Procedure 1 7 Calculation and expression of results 2 8 Test report 2 Appendix A Method for correct adjustment of airflow instrument 3 Appendix B Method for checking calibration of airfl

7、ow instrument 3 Publications referred to Inside back coverBS3181-1:1987 ii BSI 12-1999 Foreword This Part of BS3181 has been prepared under the direction of the Textiles and Clothing Standards Committee and is a revision of BS3181:1968 which is withdrawn. This revision of BS3181 is being published i

8、n two parts with Part2 describing a combined fineness/maturity test. Other British Standards relating to cotton fibres are BS2016 for determination of linear density and BS3085 for evaluation of maturity. The porous plug airflow method provides an indirect measure of fibre specific surface, that is,

9、 surface area per unit volume, which depends upon the average fibre perimeter and the average fibre maturity. If the perimeter is known, then the airflow measurement or micronaire reading may be related directly to fibre linear density or mass per unit length, which, for a certain perimeter, depends

10、 upon the maturity 1) . Conversely, if the maturity is known, then the airflow reading may be related to the perimeter. In American upland cottons (Gossypium hirsutum L.) the average fibre perimeter varies only within a narrow range and so the airflow measurement or micronaire reading can be taken a

11、s an indication of wall thickness and hence maturity for all practical purposes. Cottons of other types will not necessarily behave in the same manner. For example, American pima cottons (Gossypium barbadense L.) have a substantially smaller perimeter than the upland types and therefore give a lower

12、 micronaire reading for the same maturity. Asiatic or crossbred types show yet other relationships. The principal changes from BS3181:1968 are that the scope of the test has been restricted to raw cotton samples from bales, and the appendices dealing with particular types of airflow instruments have

13、 been deleted. Whilst the test is sometimes used for processed cotton the results obtained are dependent on the degree of processing or randomization and should be treated with caution. This standard is related to ISO2403:1972, published by the International Organization for Standardization (ISO). A

14、 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 document comprises a

15、 front cover, an inside front cover, pages i and ii, pages1 to 4, 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. 1) Lord, E. Airflow through

16、plugs of textile fibres. Part II. The micronaire test for cotton. Shirley Institute Memoirs, 1955, XXVII. Lord, E. Airflow through plugs of textile fibres. Part II. Journal of the Textile Institute, 1956, 47, T24.BS3181-1:1987 BSI 12-1999 1 1 Scope This Part of BS3181 describes a method for determin

17、ation of the micronaire value of clean raw cotton samples from bales using a single compression air flow instrument. NOTEThe titles of the publications referred to in this BritishStandard are listed on the inside back cover. 2 Principle A specimen of cotton fibre of fixed mass is brought to a fixed

18、volume and shape by compression. Air is then passed through the specimen and its permeability is indicated on the scale of the airflow instrument. From the scale reading the micronaire value of the cotton is obtained in the required units. 3 Apparatus 3.1 Airflow instrument 2) , comprising the follo

19、wing. a) Compression cylinder with perforated ends, having a negligible air-resistance. The dimensions of the cylinder are such that when a specimen, of a mass specified by the manufacturer of the instrument, is compressed each cubic centimetre contains between0.16g and0.26g of cotton. b) Means for

20、measuring the air-permeability of the specimen. This may comprise, for example, a manometer for standardizing the air pressure applied to the test specimen and a flowmeter for indicating the rate of flow through it, and hence its air-permeability. 3.2 Air pump or other suitable means, for producing

21、the required pressure difference across the test specimen. 3.3 Balance, for weighing the test specimen to an accuracy of 0.2%. 3.4 Means for producing the standard atmosphere for testing, as defined in clause4. 3.5 Specimen preparation apparatus 2) NOTEA suitable specimen preparation apparatus produ

22、ces clean randomly oriented samples. Apparatus that produces webs of predominantly parallel fibres is not suitable. 4 Atmosphere for conditioning and testing The conditioning and testing atmosphere shall be the standard temperate atmosphere for testing textiles defined in BS1051,i.e.a relative humid

23、ity of65 2% and a temperature of20 2 C. 5 Test specimens 5.1 Sampling and number of specimens The sampling scheme, the number of specimens to be tested and the number of measurements to be made on each specimen shall either be as agreed between the interested parties or shall be as follows: at least

24、 two specimens shall be prepared (see3.5) and two tests carried out on each; samples of raw cotton from bales shall be taken in accordance with BS2545. 5.2 Conditioning Before weighing out the test specimens expose the sample to the conditioning and testing atmosphere specified in clause4 for at lea

25、st4h in moving air or for at least12h in still air. 5.3 Mass of specimens The mass of the test specimens shall be as specified by the manufacturer of the airflow instrument see 3.1 a). 6 Procedure 6.1 Before each series of tests, carry out the necessary preliminary adjustments appropriate to the air

26、flow instrument (3.1). From time to time check that the airflow instrument is correctly adjusted by the method described inAppendix A. 6.2 Using the balance (3.3) weigh out a test specimen of mass appropriate to the airflow instrument (3.1) to an accuracy of 0.2%, excluding foreign bodies such as se

27、eds, sand and pieces of stalk. 6.3 Pack the test specimen evenly into the compression cylinder 3.1 a) a small portion at a time, fluffing the fibres with the fingers in order to break up any lumps and taking care that all the fibres are inserted in the cylinder. Put the compression plunger in positi

28、on and lock it. 6.4 Using the air pump or other suitable means (3.2) cause air to flow through the specimen at the pressure appropriate to the airflow instrument and note the reading on the scale of the airflow instrument to an accuracy of approximately 1%. 6.5 If a second test value is required for

29、 the same test specimen, remove the cotton from the airflow instrument, taking care not to lose fibres, and repeat the procedure given in6.3 and6.4. 2) For details of the sources of supply of a suitable airflow instrument and suitable specimen preparation apparatus apply to Enquiry Section, BSI, Lin

30、ford Wood, Milton Keynes, MK146LE, enclosing a stamped addressed envelope for reply.BS3181-1:1987 2 BSI 12-1999 7 Calculation and expression of results If the scale of the instrument is marked in arbitrary micronaire units, determine the average of the readings and express the result to the nearest0

31、.1unit. If the scale of the instrument is not marked in arbitrary micronaire units, determine the average of the readings. Using the appropriate calibration curve obtained as described inAppendix B, convert the average airflow instrument reading into micronaire units and express the result to the ne

32、arest0.1unit. 8 Test report The test report shall include the following information: a) the number and date of this British Standard,i.e.BS3181-1:1987; b) the type and model of the test instrument; c) the micronaire value for each laboratory sample (see clause7).BS3181-1:1987 BSI 12-1999 3 Appendix

33、A Method for correct adjustment of airflow instrument A.1 Apparatus See clause3. A.2 Test specimens Test specimens shall be taken from two or more reference samples of cotton 3)which have certified micronaire values within the range expected for the cotton samples that are to be tested subsequently.

34、 Conditioning and mass of specimens shall be in accordance with5.2 and 5.3. A.3 Procedure Make two determinations of micronaire value of each test specimen by the method described in clause6. The adjustments of the airflow instrument are considered satisfactory if the values obtained for the test sp

35、ecimens do not deviate from the certified values by more than 0.10micronaire units. If the deviations are greater than 0.10micronaire units repeat the procedure described in clause6 after making necessary preliminary adjustments. If the values obtained still deviate from the certified values by more

36、 than 0.10micronaire units, recalibrate the airflow instrument by the method described inAppendix B. Appendix B Method for checking calibration of airflow instrument B.1 Apparatus See clause3. B.2 Test specimens Reference samples of cotton 3)shall be used that have certified micronaire values coveri

37、ng the full range of fineness normally met. NOTEFor a full calibration over the whole scale of micronaire values normally encountered it is recommended that two test specimens of each reference sample be used. Conditioning and mass of specimens shall be in accordance with5.2 and 5.3. B.3 Procedure D

38、etermine the micronaire values of test specimens using the procedure described in clause6. The instrument is considered satisfactorily calibrated if the average value obtained for the test specimens from each reference sample does not deviate from its certified value by more than 0.10micronaire unit

39、s. If the deviations are greater than 0.10micronaire units then carry out one of the following procedures. a) Make suitable instrument adjustments (for example, alter slightly either the level of the applied air pressure difference or the scale values to which the float is adjusted when checking wit

40、h the master orifice plugs of the airflow instrument) and repeat the calibration procedure until acceptable results are obtained. b) Plot a graph showing the certified micronaire value as ordinate and the corresponding average instrument reading as abscissa. Draw a smooth curve to obtain corrections

41、 to apply to test determinations of micronaire value and so adjust them to the certified value. 3) For details of the source of supply of reference samples apply to Enquiry Section, BSI, Linford Wood, Milton Keynes, MK146LE enclosing a stamped addressed envelope for reply.4 blankBS3181-1:1987 BSI 12

42、-1999 Publications referred to BS 1051, Glossary of terms relating to the conditioning, testing and mass determination of textiles. BS 2016, Methods for the determination of the linear density of textile fibres: gravimetric methods 4) . BS 2545, Methods of fibre sampling for testing. BS 3085, Method

43、 for evaluation of the maturity of cotton fibres (microscopic method) 4) . ISO 2403, Textiles Cotton fibres Determination of micronaire value 4) . 4) Referred to in the foreword only.BS 3181-1: 1987 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent nation

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