1、BRITISH STANDARD BS 5551-2.10: 1993 ISO 5308:1992 Fertilizers Part 2: Sampling Section 2.10 Method of checking the performance of mechanical devices for sampling of solid fertilizer moving in bulk UDC 631.8:620.115.2BS5551-2.10:1993 This British Standard, having been prepared under the directionof t
2、he Chemicals Standards Policy Committee, waspublished under the authorityof the Standards Boardand comes into effect on 15February1993 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference CIC/37 Draft for comment 83/55990 DC ISBN 0 580 21959 3 Committees
3、responsible for this British Standard The preparation of this British Standard was entrusted by the Chemcials Standards Policy Committee (CIC/-) to Technical Committee CIC/37, upon which the following bodies were represented: Association of Public Analysts British Aggregate Construction Materials In
4、dustries British Coal Corporation Chemical Industries Association Consumers Association Department of Trade and Industry (Laboratory of the Government Chemist) Fertiliser Manufacturers Association Ltd. Horticultural Trades Association Institute of Trading Standards Administration Ministry of Agricul
5、ture, Fisheries and Food Ministry of Defence Amendments issued since publication Amd. No. Date CommentsBS5551-2.10:1993 BSI 10-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Normative references 1 3 Principle 1 4 Apparatus 1 5 General conditions 1 6 P
6、rocedure 1 7 Expression of results 2 8 Interpretation of results 2 List of references Inside back coverBS5551-2.10:1993 ii BSI 10-1999 National foreword This Section of BS5551 has been prepared under the direction of the Chemicals Standards Policy Committee. For some years the United Kingdom has par
7、ticipated in the standardization of methods of sampling fertilizers through Subcommittee2, Sampling, of Technical Committee134, Fertilizers and soil conditioners, of the International Organization for Standardization (ISO). As international agreement is reached on the methods, it is proposed to publ
8、ish them as Sections of BS5551. BS5551 is published in four Parts, each Part being subdivided into Sections and, where appropriate, Subsections. The four Parts are Part 1: Terminology and labelling; Part 2: Sampling; Part 3: Physical properties; Part 4: Chemical analysis. This Section of Part2 is id
9、entical with ISO5308:1992 Solid fertilizers Method of checking the performance of mechanical devices for sampling of product moving in bulk. With reference to4.3, woven wire test sieves complying with BS410:1986 are technically equivalent to, and may be used in place of, those complying with ISO3310
10、-1:1982. The Technical Committee has reviewed the provisions of ISO3310-1:1982 and has decided that they are acceptable for use in conjuction with this standard. Cross-references International Standard Corresponding British Standard BS 2846 Guide to statistical interpretation of data ISO 2602:1980 P
11、art 2:1981 Estimation of the mean: confidence interval (Identical) ISO 3301:1975 Part 6:1976 Comparison of two means in the case of paired observations (Identical) BS 5532 Statistical terminology ISO 3534:1977 Part 1:1978 Glossary of terms relating to probability and general terms relating to statis
12、tics (Identical) BS 5551 Fertilizers ISO 3963:1977 Section 2.3:1978 Sampling from a conveyor by stopping the belt reference method (Identical) ISO/TR 7553:1987 Section 2.7:1988 Recommendations for minimum mass of increment of a solid fertilizer to be taken to be representative of the total sampling
13、unit (Identical) ISO 7742:1988 Section 2.5:1989 Method for reduction of samples of solid fertilizers (Identical) ISO 8397:1988 Section 3.5:1988 Method for determination of particle size distribution by test sieving (Identical)BS5551-2.10:1993 BSI 10-1999 iii A British Standard does not purport to in
14、clude 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 front cover, an inside front cover, pag
15、es i to iv, pages1to 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.iv blankBS5551-2.10:1993 BSI 10-1999 1 1 Scope This International Stand
16、ard specifies a method of checking the performance of mechanical devices for sampling fertilizers moving in bulk by comparison of particle size distribution with that obtained by a reference method. It is applicable to any form of mechanical sampling device installed at some point in a bulk-handling
17、 system, providing that either the fertilizer passes along a conveyor belt, before or after the device, or it is subsequently packed in bags in order that a reference collection can be made. NOTE 1Although the mechanical sampling may be used for the collection of samples for chemical analysis instea
18、d of or as well as for physical testing, any bias will be more easily and economically found by size analysis than by chemical analysis of the nutrients. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this Internation
19、al Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Membe
20、rs of IEC and ISO maintain registers of currently valid International Standards. ISO 2602:1980, Statistical interpretation of test results Estimation of the mean Confidence interval. ISO 3301:1975, Statistical interpretation of data Comparison of two means in the case of paired observations. ISO 331
21、0-1:1990, Test sieves Technical requirements and testing Part 1: Test sieves of metal wire cloth. ISO 3534:1977, Statistics Vocabulary and symbols. ISO 3963:1977, Fertilizers Sampling from a conveyor by stopping the belt. ISO 7742:1988, Solid fertilizers Reduction of samples. ISO 8397:1988, Solid fe
22、rtilizers and soil conditioners Test sieving. 3 Principle Collection of two series of increments, one using a mechanical device and one using a reference method, from a quantity of fertilizer passing through a bulk-handling system, and comparison of the means and variances of the particle size distr
23、ibution of the two samples. 4 Apparatus 4.1 Rotary sample divider, complying with the requirements of ISO7742. 4.2 Sample containers 4.3 Set of sieves, complying with the requirements of ISO3310-1, of nominal aperture sizes4,00mm, 3,35mm, 2,80mm, 2,36mm, 2,00mm, 1,40mm, 1,00mm and 0,50mm. 4.4 Sieve-
24、shaking machine 5 General conditions The method of test specified in this International Standard should be carried out using a granular fertilizer. The use of a blended product may introduce additional sources of variation. If only blended fertilizer is available for this test, increments of at leas
25、t200g shall be collected (see6.1.1). It may be necessary to check the variability of the product before carrying out this test method in order to decide whether to take more increments than are specified, or to be able to conduct the test over a shorter period of time. A statistician should be consu
26、lted on the most efficient and economical method of carrying out such a check. The test shall be carried out while at least20t (and preferably not more than100t) of fertilizer passes through the mechanical sampling device. 6 Procedure 6.1 Collection of increments Carry out the operations described i
27、n6.1.1 and6.1.2 concurrently. 6.1.1 Using the mechanical sampling device under test, collect at least50 increments of a suitable size 1)and label them from A 1to A 50 , etc. 1) Information on the minimum mass of an increment is given in ISO/TR7553:1987, Fertilizers Sampling Minimum mass of increment
28、 to be taken to be representative of the total sampling unit. BS5551-2.10:1993 2 BSI 10-1999 6.1.2 Carry out one of the following reference collections. a) If the fertilizer is conveyed by a conveyor belt feeding to, or extracting from, the mechanical sampling device, collect the same number of incr
29、ements as collected in accordance with6.1.1 by stopping the conveyor belt as specified in ISO3963. If possible, synchronize the taking of the increments by the device under test with the taking of increments by the reference method, so that corresponding increments are taken from the same part of th
30、e fertilizer bed (see7.2). For example, if the reference sample is taken after the sample taken by the mechanical sampling device, it may be possible to see the gap in the fertilizer bed on the conveyor belt. b) Collect the same number of full bags as the number of increments specified in6.1.1, from
31、 the same tonnage of fertilizer, at intervals corresponding as closely as possible to the time intervals at which increments are taken in accordance with6.1.1. Label the reference increments or bags R 1to R 50 , etc. If necessary, reduce the size of the increments, or the quantities of fertilizers t
32、aken in bags, to approximately the same size as those collected in6.1.1, by the method specified in ISO7742. 6.2 Preparation of samples Combine the increments into equal groups to give at least10 individual samples taken by the same method (6.1.1 and6.1.2). The groups shall be formed of consecutive
33、increments, for example A 1toA 5 , A 6to A 10 , . . ., A 46to A 50 , etc. Mix each of the individual samples thoroughly, then, proceeding in accordance with ISO7742 using the rotary sample divider (4.1), reduce each sample to a suitable mass (200g to250g) for particle-size analysis. 6.3 Analysis of
34、samples Carry out a particle-size analysis on each of the reduced samples, obtained as described in6.2, by the method described in ISO8397 using four or five sieves from the set (4.3), chosen to suit the fertilizer used in the test. Use the same sieves for the analysis of each reduced sample. Record
35、 the percentages of fertilizer retained on each sieve and the percentage passing through the sieve with the smallest aperture. 7 Expression of results 7.1 General case where the increments taken by the two methods do not correspond exactly to each other For each series of n reduced samples, calculat
36、e the mean and the standard deviation for the percentage of fertilizer retained successively on each of the sieves and the percentage passing through the sieve with the smallest aperture size used. For each successive test sieve, calculate the value of the statistic t by means of the formula where R
37、efer to the statistical tables in ISO2602 for the significance of the values of t obtained with 2(n 1) degrees of freedom. 7.2 Special cases where the increments taken by the two methods correspond exactly to each other For each pair of reduced samples, calculate the difference between the percentag
38、es of fertilizer retained on each sieve in turn and the percentage passing through the sieve of smallest aperture size used. Calculate the mean and the standard deviation s dof these differences for each test sieve in turn and for the undersize fraction, and calculate the value of the statistic t by
39、 means of the formula Refer to the statistical tables in ISO3301 for the significance of the values of t obtained with (n 1) degrees of freedom. 8 Interpretation of results The interpretation of the individual results depends on the precision that is both acceptable and practically feasible. It is t
40、o be expected that the most significant bias will be shown by the results for the percentages of fertilizer retained on the sieve of largest aperture size and passing through the sieve of smallest aperture size used for the test, and the least significant bias by the results for the intermediate sie
41、ves.and s A are the mean and the standard deviation for the reduced samples obtained using the device (6.1.1);and s R are the mean and the standard deviation for the reduced samples obtained using the reference method(6.1.2). x A x R dBS5551-2.10:1993 BSI 10-1999 3 A mechanical sampling device shall
42、 be rejected if any of the values of t for the percentages of fertilizer retained on the sieve of largest aperture size and the percentages of fertilizer passing through the sieve of smallest aperture size are significant at the95% confidence level. The device shall be accepted as being without bias
43、 if all the values of t are not significant at the95% confidence level. In other cases, e.g. where one of the values of t is significant at the95% confidence level, indicating the possibility of bias, the tests should be repeated on a larger number of samples. NOTE 2As tests of this sort, requiring
44、larger numbers of samples, are tedious and costly to carry out, it is recommended that a statistician be consulted before further tests are carried out. Additional information on the performance of the tested device can be obtained by comparing the variances and obtained in7.1 using the F- test as d
45、efined in ISO3534. In the special case (7.2), and may be calculated in the normal way from the individual results. If a significantly larger variance is obtained for the tested mechanical device than for the reference method, this implies that the device is not reliable. s A 2 s R 2 s A 2 s R 24 bla
46、nkBS5551-2.10:1993 BSI 10-1999 List of references See national foreword.BS 5551-2.10: 1993 ISO 5308:1992 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 standards in Eu
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