1、BRITISH STANDARD BS 1751:1997 ISO 4785:1997 Laboratory glassware Specification for straight-bore glass stopcocks for general purposes ICS 71.040.20BS1751:1997 This British Standard, having been prepared under the direction of the Sector Board for Materials and Chemicals, was published under the auth
2、ority of the Standards Board and comes into effect on 15 August 1997 BSI 09-1999 ISBN 0 580 28079 9 National foreword The UK participation in the preparation of this British Standard was entrusted by Technical Committee LBI/36, Laboratory glassware and related apparatus, to Subcommittee LBI/36/2, Ge
3、neral laboratory glass and plastics ware. It is identical with ISO4785:1997 Laboratory glassware Straight bore glass stopcocks for general purposes published by the International Organization for Standardization (ISO). It supersedes BS1751:1985 which is withdrawn. A list of organizations represented
4、 on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence
5、 Index”, or using the “Find” facility of the BSI Standards Electronic Catalogue. 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
6、confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the ISO title page, pages ii to iv, pages 1 to 4, an inside back cover and abackcover. This standard has been updated (see copyright date) and may have had amendment
7、s incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date CommentsBS1751:1997 BSI 09-1999 i Contents Page National foreword Inside front cover Foreword iii Text of ISO 4785 1ii blankBS1751:1997 ii BSI 09-1999 Contents P
8、age Foreword iii 1 Scope 1 2 Normative references 1 3 Ground zone 1 4 Dimensions and series of sizes 1 5 Side arms 1 6 Material 1 7 Construction 1 8 Dimensions 3 9 Designation 3 10 Marking 3 Annex A (informative) Bibliography Inside back cover Figure 1 Straight-bore stopcock, general appearence 2 Fi
9、gure 2 Test according to clause5 2 Figure 3 Assembled stopcock 3 Table 1 Dimensions and tolerances of the ground zone 3 Table 2 Nominal dimensions of ground zone and bore diameter 4 Table 3 Recommended dimensions for side arms 4 Descriptors: Laboratory equipment, laboratory glassware, stopcocks, spe
10、cifications, dimensions, designation.BS1751:1997 BSI 09-1999 iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical c
11、ommittees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with t
12、he International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least75% of the me
13、mber bodies casting a vote. This International Standard ISO 4785 has been prepared by Technical Committee ISO/TC 48, Laboratory glassware and related apparatus, Subcommittee SC 2, General laboratory glassware (other than measuring apparatus). Annex A of this International Standard is for information
14、 only.iv blankBS1751:1997 BSI 09-1999 1 1 Scope This International Standard specifies requirements and dimensions for two series of glass straight-bore stopcocks for general-purpose use. The stopcocks are defined by their nominal (bore) diameter and large end diameter and length of the ground zone.
15、It is recommended that, in national standards, only one of the series should be specified. NOTEAnnex A lists additional International Standards for other general-purpose laboratory glassware. 2 Normative references The following standards contain provisions which, through reference in this text, con
16、stitute provisions of this International 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 o
17、f the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 719:1985, Glass Hydrolytic resistance of glass grains at 98 C Method of test and classification. ISO 3585:1991, Borosilicate glass 3.3 Properties. ISO 4803:1978, Laboratory glas
18、sware Borosilicate glass tubing. 3 Ground zone 3.1 The taper of the ground zone shall be such as to give one increment on the diameter for ten increments on the axial length, with a tolerance of 0,006on the diameter increment i.e.a taper of(1 0,006)/10. NOTE 1This tolerance is in agreement with the
19、relevant requirement of ISO383. Annex B in ISO383:1976 describes a leakage test with air which may be used to check the tightness of the ground zone. NOTE 2Actual manufacturing techniques normally result in a tighter tolerance than that given above, but owing to the lack of experimental evidence it
20、is not yet possible to reduce the specified value. 3.2 The centreline average height of the ground surface shall not exceed14m and should preferably be less than0,54m. NOTEThe “centreline average height” of the ground surface is the average value R aof the surface roughness as defined in ISO468. 4 D
21、imensions and series of sizes 4.1 The nominal diameters of series I stopcocks shall be as follows (given in millimetres): 11,52,54610 NOTEThis is the R 5 series of preferred numbers. 4.2 The nominal diameters of series II stopcocks shall be as follows (given in millimetres): 11,523456810 4.3 The dim
22、ensions and tolerances of the ground zone shall be as shown in Table 1 and Figure 1. 4.4 The allocation of bore diameters to key and barrel dimensions shall be as shown in Table 2. 5 Side arms The side arms shall be fused to the barrel so as to enable a pin of thickness0,8times the nominal bore to f
23、it at least to the middle of the length of the bore. See Figure 2 for details. Recommended dimensions for the side arms are given in Table 3. In the case of stopcocks made from borosilicate glass3.3, tubes in accordance with ISO4803 should be used. 6 Material 6.1 Stopcocks should preferably be made
24、from borosilicate glass3.3in accordance with ISO3585. When tested according to the procedure and classification given in ISO719, the glass shall comply with the requirements of class HGB3 or better. The glass should be as free as possible from visible defects and reasonably free from internal stress
25、 which would impair the performance of the stopcock. 6.2 Both the key and barrel of a stopcock should preferably be fabricated from the same type of glass. 7 Construction The key may be solid or hollow at the manufacturers discretion. The key may project slightly beyond the base of the ground zone a
26、nd can be fitted with a suitable retaining device (see Figure 3). The rims of the barrel should be suitably strengthened, in order to avoid chipping. The construction should be sufficiently robust to withstand normal usage.BS1751:1997 2 BSI 09-1999 Figure 1 Straight-bore stopcock, general appearence
27、 Figure 2 Test according to clause5BS1751:1997 BSI 09-1999 3 8 Dimensions The dimensions shall be as given in Table 1 to Table 3. 9 Designation For convenience of reference to stopcocks complying with the requirements of this International Standard, the use of a designation is recommended, consistin
28、g of the following dimensions, expressed in millimetres: nominal bore diameter (e.g.4), and large end diameter of the ground zone (e.g.18,8), and the number of this International Standard. EXAMPLE: Stopcock ISO4785,418,8 10 Marking The size of the large end diameter of the ground zone according to T
29、able 2 shall be marked on the barrel of each stopcock in such a way as to be permanent under normal conditions of use: EXAMPLE: 18,8 Table 1 Dimensions and tolerances of the ground zone Figure 3 Assembled stopcock Dimensions in millimetres d 1 a I 1 b I 2 7,5 0,008 22 11 0,215 8 0,008 20 10 0,215 10
30、 0,008 25 12,5 0,215 12,5 0,01 28 14 0,215 13,5 0,01 30 15 0,215 14,5 0,01 30 15 0,215 18,8 0,015 38 19 0,26 19 0,015 40 20 0,26 21,5 0,015 44 22 0,26 22,2 0,015 44 22 0,26 27,6 0,015 52 26 0,26 29,2 0,015 58 29 0,26 37,8 0,015 56 28 0,26 a The tolerances are in agreement with the relevant requireme
31、nts of ISO383. b As I 2is the essential dimension, I 1is left without tolerances.BS1751:1997 4 BSI 09-1999 Table 2 Nominal dimensions of ground zoneand bore diameter Table 3 Recommended dimensions for sidearms Dimensions in millimetres d 1 I 1 d n Series I Series II 7,5 22 1 8 20 1 10 25 1 12,5 28 1
32、,5 13,5 30 1 13,5 30 1,5 13,5 30 2 14,5 30 2,5 18,8 38 4 19 40 3 19 40 4 21,5 44 6 22,2 44 5 22,2 44 6 27,6 52 8 29,2 58 10 37,8 56 10 Dimensions in millimetres d 2 I 3 d n 0,4 min. Series I Series II 7 115 1 7 100 1 8 100 1,5 7 115 1 8 115 1,5 8 115 2 9 100 2,5 10 110 4 10 115 3 10 115 4 13 120 6 1
33、2 115 5 12 130 6 14 130 8 18 120 10 17 140 10BS1751:1997 BSI 09-1999 5 Annex A (informative) Bibliography 1 ISO 383:1976, Laboratory glassware Interchangeable conical ground joints. 2 ISO 384:1978, Laboratory glassware Principles of design and construction of volumetric glassware. 3 ISO 468:1982, Su
34、rface roughness Parameters, their values and general rules for specifying requirements. 4 ISO 641:1975, Laboratory glassware Interchangeable spherical ground joints. 5 ISO 1773:1997, Laboratory glassware Narrow-necked boiling flasks. 6 ISO 3819:1985, Laboratory glassware Beakers. 7 ISO 4142:1997, La
35、boratory glassware Test tubes and culture tubes. 8 ISO 4796:1977, Laboratory glassware Bottles. 9 ISO 4797:1981, Laboratory glassware Flasks with conical ground joints. 10 ISO 4798:1997, Laboratory glassware Filter funnels. 11 ISO 4799:1978, Laboratory glassware Condensers. 12 ISO 4800:1977, Laborat
36、ory glassware Separating funnels and dropping funnels. 13 ISO 6556:1981, Laboratory glassware Filter flasks.BS 1751:1997 ISO 4785:1997 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents
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