1、BRITISH STANDARD BS 6620-1: 1991 ISO 7805-1: 1984 Industrial plate screens Part 1: Guide for screens of thickness3mm and aboveBS6620-1:1991 This British Standard, having been prepared under the directionof the General Mechanical Engineering Standards Policy Committee, waspublished under the authorit
2、yof the Standards Boardand comes into effect on 31 January 1992 BSI 10-1999 First published as BS6620 September1985 Second edition as BS6620-1 January1992 The following BSI references relate to the work on this standard: Committee referenceGME/29 Draft for comment 83/72051DC ISBN 0 580 20391 3 Commi
3、ttees responsible for this British Standard The preparation of this British Standard was entrusted by the General Mechanical Engineering Standards Policy Committee (GME/-) to Technical Committee GME/29, upon which the following bodies were represented: BCIRA British Aggregate Construction Materials
4、Industries British Ceramic Society British Laboratory Ware Association Cement and Concrete Association Cement Makers Federation Coated Abrasives Manufacturers Association Department of Trade and Industry (Warren Spring Laboratory) Department of Transport (Highways) Guild of Metal Perforators Incorpo
5、rated National Association of British and Irish Millers Institution of Chemical Engineers Institution of Mining and Metallurgy Mechanical Handling Engineers Association Ministry of Defence National Coal Board Society of Chemical Industry Woven Wire Association The following body was also represented
6、 in the drafting of the standard, through subcommittees and panels: Minerals Engineering Society Amendments issued since publication Amd. No. Date CommentsBS6620-1:1991 BSI 10-1999 i Contents Page Committees responsible Inside front cover National foreword ii 0 Introduction 1 1 Scope and field of ap
7、plication 1 2 References 1 3 Definitions 1 4 Material and design 1 5 Tolerances 2 6 Testing 2 7 Designation 3 Annex Examples 4 Figure 1 Round holes:60 staggered arrangement 1 Figure 2 Square holes: in-line arrangement 2 Figure 3 Square holes: half-pitch staggered arrangement 2 Table 1 Pitch/hole rat
8、ios and related open areas 2 Table 2 Examples of round hole perforations at60 stagger inindustrialplatescreens 4 Table 3 Examples of square hold perforations in industrial plate screens 5 Table 4 Examples of tolerances on pitch 5 Publication(s) referred to Inside back coverBS6620-1:1991 ii BSI 10-19
9、99 National foreword This Part of BS6620 has been prepared under the direction of the General Mechanical Engineering Standards Policy Committee and is identical withISO7805-1:1984 “Industrial plate screens Part 1: Thickness of3mm and above” published by the International Organization for Standardiza
10、tion (ISO). ISO7805-1 was prepared byISO/TC24 in which the UK took an active part. BS6620-1:1991 supersedes BS6620:1985, which is withdrawn. The difference between the two editions is that the standard has been renumbered to align it with BS6620-2:1991. No other change has been made. The Technical C
11、ommittee has reviewed the provisions of ISO2194, ISO2395, ISO3310-2 and ISO7805-2, to which reference is made in the text, and has decided that they are suitable for use in conjunction with this standard. ISO 2194 and ISO3310-2 are related to BS410 “Specification for test sieves” and ISO2194 is also
12、 related to BS481 “Specification for industrial wire mesh” Part2 “High tensile steel wire mesh with square apertures from125mm to2mm”. 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.
13、Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references InternationalStandard Corresponding British Standard ISO 3:1973 BS 2045:1965 Preferred numbers (Technically equivalent) ISO 7805-2:1987 BS 6620 Guide for industrial plate screens Part 2:199
14、1 Thickness below3mm (Identical) ISO 7806:1983 BS 6511:1984 Specification for designation of perforations in industrial plate screens (Identical) Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1to6, an inside back cover and a back cover. This standa
15、rd 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.BS6620-1:1991 BSI 10-1999 1 0 Introduction The purpose of this InternationalStandard is to provide guidance for the development of national stand
16、ards for industrial plate screens. 1 Scope and field of application This part of ISO7805 describes three patterns using round (circular) and square perforations in low carbon steel plate of3mm thickness and above; the sizes of holes ranging from125 to3,15mm inclusive. Five ratios of pitch to hole ar
17、e prescribed which result in nominal areas ranging from about64 to23%. Tolerances for both hole and pitch are given. As this part of ISO7805 provides a diversity of choice, it is unlikely that every one of the many possible combinations of size of hole, pitch and plate thickness will be manufactured
18、. The selection for national standards for industrial plate screens should be made from those combinations which suit the products and screening methods in the country concerned. Industrial plate screens of thicknesses below3mm are dealt with in ISO7805-2. 2 References ISO 3, Preferred numbers Serie
19、s of preferred numbers. ISO 2194, Wire screens and plate screens for industrial purposes Nominal sizes of apertures. ISO 2395, Test sieves and test sieving Vocabulary. ISO 3310-2, Test sieves Technical requirements and testing Part2: Metal perforated plate. ISO 7805-2, Industrial plate screens Part2
20、:Thickness below3mm 1) . ISO 7806, Industrial plate screens Codification for designating perforations. 3 Definitions For the purpose of this InternationalStandard the definitions given in ISO2395 and the following definition apply. open area ratio of the total area occupied by the holes to the overa
21、ll area of the perforated part of the plate 4 Material and design 4.1 Material The following requirements apply to perforated plates of low-carbon steel. Plates made of other steels and non-ferrous metals may require different specifications apart from sizes of holes. 4.2 Design 4.2.1 Arrangement of
22、 holes Three permissible arrangements of holes are illustrated inFigure 1 toFigure 3; Figure 1 for round holes in an equilateral triangle(60staggered) arrangement;Figure 2 andFigure 3 for square holes in line or at half pitch stagger. 4.2.2 Size of holes w The nominal sizes of round or square holes
23、in industrial plate screens are tabulated in ISO2194. First choice shall be made from the R10 series of preferred numbers, the second choice from theR20series. If necessary, choice may be made from the R40series. NOTEThe R10series of sizes is shown, by way of example, inTable 2 andTable 3. 1) At pre
24、sent at the stage of draft. Figure 1 Round holes:60 staggered arrangement (i.e. at the apices of equilateral triangles) Open area . 0,9 (w/p) 2 BS6620-1:1991 2 BSI 10-1999 4.2.3 Pitch p Values for pitch shall be calculated from the five options of pitch/hole ratio given inTable 1 which tabulates the
25、 approximate open area in percent for round and square hole perforations based on these ratios. The calculated values shall be rounded to the nearest R40number according to ISO3. Table 1 Pitch/hole ratios and related openareas 4.2.4 Plate thickness Plate thickness before perforation shall be agreed
26、by purchaser and supplier. A chosen thickness shall normally be less than the size of holes and also less than the bridge width (bar). 5 Tolerances Formulae for tolerances are given in5.1 to5.3; they apply to unused plate screens. 5.1 Tolerance on average size of hole %w The average measured size of
27、 hole shall not deviate from the nominal value by more than the value given by the formula where %w and w are given in millimetres. 5.2 Tolerance on average pitch %p The average measured pitch shall not deviate from the nominal value by more than the value given by the formula where %p and p are giv
28、en in millimetres. 5.3 Tolerance on individual pitch The measured value of any individual pitch shall not deviate from the nominal value by more than2%p. NOTEExamples are listed inTable 2 andTable 3 for tolerances on average size of hole and inTable 4 for tolerances on average pitch. 6 Testing Measu
29、rements of size of holes and pitch in perforated plate shall be made at the punch side of the plate as described in tests2 and3 of ISO3310-2. Figure 2 Square holes: in-line arrangementOpen area = (w/p) 2 Figure 3 Square holes: half-pitch staggeredarrangement Open area = (w/p) 2 Pitch/hole ratio Appr
30、oximate open area round holes square holes p/w % % 1,25 1,4 1,6 1,8 2 58 46 35 28 23 64 51 39 31 25 NOTEExamples inTable 2 andTable 3 include pitch selections. . . .(1) . . .(2)BS6620-1:1991 BSI 10-1999 3 7 Designation Industrial plate screens shall be designated by shape of holes; size of holes; ar
31、rangement and orientation of holes; pitch of holes. The above items of designation can be described by use of the code specified in ISO7806. NOTEThe customers choice of plate thickness, shape and size of plate, and the required material should be clearly stated when ordering an industrial plate scre
32、en.BS6620-1:1991 4 BSI 10-1999 Annex Examples (This annex forms part of the Standard.) Table 2 andTable 3 are examples which list sizes of holes in theR10 series and include hole/pitch combinations which have been manufactured or suggested. The criteria for selection made for national standards is d
33、escribed in clause1. Table 2 Examples of round hole perforations at60 stagger in industrial plate screens Values in millimetres Hole Nominal pitch a p for an approximate open area of nominal size tolerance on average size w % w 58% 46% 35% 28% 23% 125 100 80 63 50 40 31,5 25 20 16 12,5 10 8 6,3 5 4
34、3,15 3 2,5 2,1 1,7 1,4 1,2 1 0,8 0,6 0,5 0,4 0,35 0,3 0,25 0,2 0,15 0,15 160 125 100 80 63 50 40 31,5 25 20 16 90 71 56 45 35,5 28 22,4 18 14 11,2 100 80 63 50 40 31,5 25 20 16 12,5 10 8 22,4 18 14 11,2 9 7,1 16 12,5 10 8 6,3 a For tolerances on pitch seeTable 4.BS6620-1:1991 BSI 10-1999 5 Table 3 E
35、xamples of square hole perforations in industrial plate screens Table 4 Examples of tolerances on pitch Values in millimetres Hole Nominal pitch a p for an approximate open area of nominal size tolerance on average size w % w 64% 51% 39% 31% 25% 125 100 80 63 50 40 31,5 25 20 16 12,5 10 8 6,3 5 4 3,
36、15 3 2,5 2,1 1,7 1,4 1,2 1 0,8 0,6 0,5 0,4 0,35 0,3 0,25 0,2 0,15 0,15 160 125 100 80 63 50 40 31,5 25 20 16 90 71 56 45 35,5 28 22,4 18 14 11,2 100 80 63 50 40 31,5 25 20 16 12,5 10 18 14 11,2 9 7,1 10 8 6,3 a For tolerances on pitch seeTable 4. Values in millimetres Nominal pitch Tolerance on aver
37、age pitch Nominal pitch Tolerance on average pitch p %p p %p 160 125 100 90 80 71 63 56 50 45 40 35,5 31,5 2,9 2,4 2 1,8 1,7 1,5 1,4 1,3 1,2 1,1 1 0,8 0,8 28 25 22,4 20 18 16 14 12,5 11,2 10 9 8 7,1 6,3 0,7 0,7 0,6 0,5 0,5 0,45 0,4 0,35 0,35 0,3 0,25 0,25 0,2 0,2 NOTEThe tolerance on any individual
38、pitch is twice that stated for average pitch.6 blankBS6620-1:1991 BSI 10-1999 Publication(s) referred to See national foreword.BS 6620-1: 1991 ISO 7805-1: 1984 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing Briti
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