1、BRITISH STANDARD BS 4427-5: 1974 Methods of test for Sodium tripolyphosphate (pentasodium triphosphate) and sodium pyrophosphate (tetrasodium pyrophosphate) for industrial use Part 5: Determination of particle size distribution UDC 661.833.456 + 661.833.458:546.33185:620.168.32BS4427-5:1974 This Bri
2、tish Standard, having been approved by the ChemicalsIndustry StandardsCommittee, was published under the authorityofthe Executive Boardon 7 June 1974 BSI 11-1999 The following BSI references relate to the work on this standard: Committee reference CIC/25 Draft for comment 72/55290 ISBN 0 580 08011 0
3、 Co-operating organizations The Chemicals Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representatives of the following Government departments and scientific and industrial organizations: British Steel Industry Chemical Industries Association*
4、 Department of Health and Social Security Department of Trade and Industry-Chemicals and Textiles Division Department of Trade and Industry-Laboratory of the Government Chemist* Fertiliser Manufacturers Association Limited* Ministry of Agriculture, Fisheries and Food National Sulphuric Acid Associat
5、ion Royal Institute of Public Health and Hygiene Soap and Detergent Industry Association The Government department and industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this Br
6、itish Standard: British Pharmacopoeia Commission Campden Food Preservation Research Association Flour Milling and Baking Research Association Institute of Metal Finishing National Association of Soft Drink Manufacturers Society for Water Treatment and Examination Textile Institute Amendments issued
7、since publication Amd. No. Date of issue CommentsBS4427-5:1974 BSI 11-1999 i Contents Page Co-operating organizations Inside front cover Foreword ii 1 Scope 1 2 Principle 1 3 Apparatus 1 4 Procedure 1 5 Expression of results 1 6 Test report 2 Figure 1 Diagram of movements in the horizontal plane 2 P
8、ublication referred to Inside back coverBS4427-5:1974 ii BSI 11-1999 Foreword This British Standard has been prepared under the authority of the Chemicals Industry Standards Committee in order to provide methods for the analysis of sodium tripolyphosphate and sodium pyrophosphate. For some years the
9、 UnitedKingdom has participated in the work of preparing methods of test applicable to sodium tripolyphosphate and sodium pyrophosphate for industrial use, organized by Subcommittee6(formerly Working Group7), “Phosphoric Acid and Condensed Phosphates” of Technical Committee 47 “Chemistry” of the Int
10、ernational Organization for Standardization (ISO). As international agreement is reached on the methods, it is proposed to publish them as Parts of this British Standard. This Part is based on International Standard ISO 2996 “Sodium tripolyphosphate and sodium pyrophosphate for industrial use Partic
11、le size distribution by mechanical sieving”, modified to take into account the comments made by the UnitedKingdom during its development. This standard specifies methods of test only and should not be used or quoted as a specification defining limits of purity. Reference to the standard should be in
12、 a form of words indicating that the methods of test used conform to the requirements of BS4427. 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 doe
13、s not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 and 2, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. Th
14、is will be indicated in the amendment table on the inside front cover.BS4427-5:1974 BSI 11-1999 1 1 Scope This Part of BS 4427 specifies a mechanical sieving method for determination of the particle size distribution of pentasodium triphosphate and tetrasodium pyrophosphate for industrial use. NOTET
15、he title of the British Standard referred to in this Part is given on the inside back cover. 2 Principle A test portion is mechanically sieved under fixed conditions and each of the fractions is weighed. 3 Apparatus Ordinary laboratory apparatus and the following are required: 3.1 Series of circular
16、 sieves, complying with the requirements of BS410, with metallic mountings, approximately200mm diameter, capable of being fitted tightly together and including a base and a cover. The apertures shall be chosen, according to the characteristics of the product to be examined, from the following series
17、: mm 0.063 0.125 0.250 0.500 1.0 2.0 4.0 NOTEThese apertures are specified in BS410. 3.2 Automatic device 1) , capable of applying to a set of four sieves, complete with base and cover, a combination of movements in the horizontal plane and impacts along the vertical axis. The movement in the horizo
18、ntal plane is defined as follows (see Figure 1, in which the cross-hatched area indicates the plan of the sieve cascade). The centre of the sieves shall follow the same path as the mid-point C of a straight line AB of length380mm. One extremity A of this line describes a circle, of radius r = 20mm,
19、in a horizontal plane. The other extremity B is constrained to describe a straight line, of length 2r = 40mm, lying on the line passing through the centre O of the circle. The complete movement shall be repeated about300times per minute. The vertical impacts are produced by a weight of about1.2kg fa
20、lling from a height of40mm onto a rubber pad centrally located on a plate on the cover. The frequency of impacts shall be about150impacts per minute and these shall not give rise to a vertical displacement of the sieves of greater than0.5mm. 3.3 Oven, capable of being controlled at105 2 C. 4 Procedu
21、re 4.1 Test portion. Dry the laboratory sample in the oven (3.3), controlled at105 2 C, for1h and allow to cool in a desiccator. Weigh, to the nearest 0.01g, 50 0.02g of the dried laboratory sample. 4.2 Determination. Choose from the series of sieves (3.1) four sieves which have apertures appropriat
22、e to the characteristics of the product to be examined. Fit these four sieves, cleaned and dried, one within the other in the order of decreasing aperture size. Place the sieve with the smallest apertures at the bottom, on the base. Place the sieve with the largest apertures at the top. Transfer qua
23、ntitatively the test portion (4.1) to the topmost sieve and close the sieve with the cover. Clamp the column of sieves on the shaking device(3.2) and connect to earth by a conductor. Carry out the sieving for 30min. Weigh the contents of each sieve to the nearest0.01g. Verify that the total of the m
24、asses obtained is equal, to the nearest0.1g, to the mass of the test portion. If it is not, repeat the determination with a fresh test portion. 5 Expression of results Calculate for each sieve: a) the mass (m), in grams, of product equal to the sum of the mass contained in that sieve and the masses
25、contained in the sieves above; b) the percentage of the test portion passing through each sieve, given by the expression:100 2m. Express the results in the form of a table summarizing the percentages passing through the different sieves, commencing with the sieve with the largest aperture. 1) A devi
26、ce conforming to the specification is commercially available and information on suppliers may be obtained from the British Standards Institution, 2Park Street, London W1A2BS.BS4427-5:1974 2 BSI 11-1999 6 Test report The test report shall include the following particulars: a) the reference of the met
27、hod used, i.e. BS 4427-5; b) the results and the method of expression used; c) any unusual features noted during the determination; d) any operation not included in this British Standard or regarded as optional. Figure 1 Diagram of movements in the horizontal planeBS4427-5:1974 BSI 11-1999 Publicati
28、on referred to This standard makes reference to the following British Standard: BS 410, Test sieves. BS 4427-5: 1974 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on sta
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