1、BS 572 : 1985 UDC 542.231.7 : 666.285.6 British Standards Institution. No patt of this publication may be photocopied or otherwise (epmduced without the prior permission in writing of BSI British Standard Specification for Interchangeable conical ground glass joints Assemblages coniques rods interch
2、angeables en verre - Spcifications Austauschbare Kegelschliffverbindungen Brit ish Standards I nsti tu ti on _- - BSI BSM572 85 So 1b24bb9 0119427 8 M Foreword This British Standard has been prepared under the direction of the Laboratory Apparatus Standards Committee. It is a revision of BS 572 : 19
3、60, which is withdrawn. The technical requirements are the same as those of IS0 383-1 976 Laboratory glassware - Interchangeable conical ground joints published by the International Organization for Standardization (ISO), but the text has been editorially rearranged to improve clarity. However, a ma
4、rking clause similar to that in BS 572 : 1960 has been retained in this revision, The purpose of this standard is to ensure interchangeability between standard conical ground glass joints, irrespective of where they are manufactured. In order to achieve interchangeability, it is necessary that each
5、of the following requirements be adequately specified, including appropriate tolerances: (a) taper; (b) large end diameter; (c) length of ground zone; (d) surface finish. The nominal dimensions listed in table 1 are based on the series of joints already widely used in many countries; in particular,
6、the series of large end diameters represents the nearest acceptable compromise to the R 40/3 series of preferred numbers recommended in BS 2045. From the practical point of view, and especially because of the difficulty of carrying out precise measurements on the ground portions of the finished join
7、ts, it is desirable to apply a gauging system that allows rapid checking of the essential dimensions. The definition of these dimensions in clause 5 is an integral part of this standard, but the system of gauging described in appendix A, while it has been proved in practice to be fully satisfactory,
8、 is not the only one that can be applied for the purpose. The leakage test described in appendix B is that commonly used for testing joints, but its inclusion in this standard is not intended to preclude the use of other tests which may be found more convenient for particular purposes, Attention is
9、specifically drawn to the method of pneumatic gauging“. The principal differences from the 1960 edition of this standard are: (a) the elimination of the former BS designation, permitted as an alternative; (b) the inclusion of a further series of joints based on a value of eight for the constant for
10、the calculation of the length of the ground zone (see clause 4); (c) two sizes of joints have been deleted and five have been added, in particular three larger sizes in the series based on a value of six for the constant for the calculation of the length of the ground zone; (d) the gauging system (s
11、ee appendix A) is now a recommended procedure instead of the only one allowed. Compliance with a British Standard does not of itself confer immunity from legal obligations. *This method is described by Smith, I.C.P., Pneumatic gauging applied to standard ground glass joints, Laboratory Practice, 195
12、8, 7, (3). - O a l ! I I 1 a -1 BSI BS*572 85 I Jb24bb 0339428 T I BS 572 : 1985 Contents Foreword Committees responsible Page Inside front cover Back cover Specification 1 Scope 2 2 Designation 2 3 Large end diameter 2 4 Length of ground zone 2 5 Tolerances on diameter and length 2 6 Taper 4 7 Surf
13、ace finish 4 8 Marking 4 Appendices A Suitable gauging system for diameter and length B Leakage test for conical joints 6 of conical joints 5 Tables 1 Nominal dimensions of conical joints 2 Dimensions and tolerances of the dimensional frame for checking dimensions of sockets and cones 3 2 Figures 1
14、Dimensions of conical ground glass joints 4 2 Gauge for sockets 5 3 Gauge for cones 5 4 Suitable apparatus for leakage test on conical joints 6 r I BS 572 : 1985 Specification 1 Scope This British Standard specifies the essential geometric requirements for interchangeability in relation to four seri
15、es of conical ground glass joints for laboratory use. NOTE 1. The term cone is used in this British Standard for the part which is inserted and the term socket for the part into which the cone is inserted. NOTE 2. The titles of the publications referred to in this standard are listed on the inside b
16、ack cover. 2 Designation (see table 1) Joints shall be designated by two numbers, separated by an oblique or horizontal stroke, as follows: (a) the rounded value of the large end diameter of the joint in millimetres; (b) the nominal length of the ground zone in millimetres. 19 26 NOTE. Examples of d
17、esignation: 19/26 or -. 3 Large end diameter The following series of nominal diameters of the large end of the ground zone shall be adopted: 5, 7.5, IO, 12.5, 14.5, 18.8, 21.5, 24, 29.2,34.5, 40, 45, 50,60, 71,85, 100 mm. 4 Length of ground zone The length of the ground zone I, in millimetres, (see
18、figure 1) shall be calculated using the following equation and rounded to the nearest whole number /=kT k is a constant = 2,4,6 or 8 for the four series; d is the large end diameter (in mm). where NOTE. The four series of joints listed in table 1 are obtained by using the values, 2, 4,6 and 8 for th
19、e constant k. Joints based on the value 6 for the constant are the preferred series. 5 Tolerances on diameter and length The diameter and length of the ground zone shall be such that, when it is placed with its axis in the plane of the dimensional frame shown in figure 1, it fits in.such a way that
20、the upper and lower edges of the ground zone fall within the zonesof height hl and h, respectively, the values of ci, I, h, and h2 for any particular joint size being taken from table 2. NOTE. For special purposes, the ground zone may extend beyond the outer limit of zoneh, ,provided that it also ex
21、tends into zone h, . A system of gauging suitable for determining whether joints fall within these limits is described in appendix A. Table 1. Nominal dimensions of conical joints Designation k=2 1919 2411 O 2911 1 3411 2 4011 3 4511 3 5011 4 k=4 519 711 1 10113 12/14 1411 5 1911 7 21/19 24/20 29/22
22、 34/23 k=6 (preferred series) 511 3 711 6 10119 12/21 . 14/23 19/26 21/28 24/29 29/32 34/35 40138 45/40 50142 60146 7 1 I51 85155 100160 k=8 511 8 7/22 10125 12/28 14/30 19/35 21 137 24139 29/43 34/47 Nominal diameter of large end of ground zone mm 18.8 24.0 29.2 34.5 40.0 45.0 50.0 5.0 7.5 10.0 12.
23、5 14.5 18.8 21.5 24.0 29.2 34.5 5.0 7.5 10.0 12.5 14.5 18.8 21.5 24.0 29.2 34.5 40.0 45.0 50.0 60.0 71 .O 85.0 100.0 5.0 7.5 10.0 12.5 14.5 18.8 21.5 24.0 29.2 34.5 Nominal length of ground zone measured axially mm 9 10 11 12 13 13 14 9 11 13 14 15 17 19 20 22 23 13 16 19 21 23 26 28 29 32 35 38 40
24、42 46 51 55 60 18 22 25 28 30 35 37 39 43 47 _ . :. BS 572 : 1985 Table 2. Dimensions and tolerances of the dimensional frame for checking dimensions of sockefs and cones (See clause 6 and figures 1,2 and 3) Designation Diameter, d, -I- 1919 24/10 2911 1 3411 2 4011 3 45/13 5011 4 18.9 24.1 29.3 34.
25、6 40.1 45.1 50.1 b f 0.015 Overall length, I, mm 8 9 10 11 f 0.015 11 11 12 Upper step height, h, 2.5 2.5 . I 0.010 2.5 2.5 2.5 , Lower step height, h, 2.0 . IO.010 2.5 2.5 2.5 , . e?. . .- BS572 : 1985 6 Taper The taper of the joints shall be such as to give one increment on diameter for ten increm
26、ents on axial length, with a tolerance of (1 .O0 f 0.006)/10. NOTE. Actual manufacturing techniques normally result in a tighter tolerance than that given above but, owing to the lack of experimental evidence, it is not yet possible to reduce the specified value. 7 Surface finish The ground matt sur
27、face shall have a roughness value (,)“ of less than 1 pm when tested in accordance with BS 1134 : Part 1. 8 Marking Each cone and each socket shall be permanently and legibly barked as near as possible to the ground portion with: .=-A A Othe designation, e.g. 5/13; -. (c) the makers or vendors name
28、or mark. A+ hese inscriptions shall be employed whether the cones and sockets form integral parts of an apparatus or are supplied as individual items. NOTE. When joints form part of other apparatus it is to be understood that this marking relatest to the joint only and it should therefore be so plac
29、ed as to be directly associated with the joint. I- d Figure 1. Dimensions of conical ground glass joints 4 BSI BS*572 85 H Lb24669 OLL9432 L H BS 572 : 1985 Appendices Appendix A. Suitable gauging system for diameter and length of conical joints The recommended gauges are made of hardened steel or o
30、ther suitable material. The gauges for sockets are conical plugs with a step at each end, and the gauges for cones are conical rings with a step at each end; they are shown in figures 2 and 3. The cone semi-angle of each gauge is 2“ 51 45“ f 15“. (The sine of the specified angle is 0.049 94 f 0.000
31、07.) h2 Figure 2. Gauge for sockets A separate gauge is required for each size of cone or socket, the gauge dimensions being given in table 2. When a socket or cone is fitted to its appropriate gauge, it should rest in such a position that the upper and lower ends of the ground zone lie wholly withi
32、n the steps of height hl and h2 respectively. For special purposes, the ground surface may extend beyond the outer extremity of the step at the smaller end, provided that it also extends to at least the inner extremity of the step at the larger end, Figure 3. Gauge for cones 5 - BS 572 : 1985 BSI BS
33、*572 85 B 1b24669 OE19433 3 I Appendix B. Leakage test for conical joints The leakage test is carried out on dry joints by observing the rate of increase in pressure in a previously evacuated system in communication with the atmosphere via the leaking joint. A suitable apparatus is used, as illustra
34、ted in figure 4, the details not being essential, provided that the total capacity of the system is approximately 1.5 L. It is essential to render all joints in the testing apparatus leak- proof and to check the apparatus before coupling in the joint to be tested, It is essential that leakage found
35、during checking be negligible in comparison with the leakage measured during the test. The degree of cleanliness of the ground surface is a vital factor affecting the rate of leakage. The components are first rubbed with a cloth soaked in a suitable solvent, for example cyclohexane, then dipped in t
36、he solvent and allowed to dry. Any particles adhering to the surfaces are removed with a camels-hair brush. The components are then placed in turn in a vertical position in the apparatus and the system evacuated. No pressure, other than that exerted by the atmosphere, is applied to the joint. When t
37、he mercury gauge reading is above 380 mm, the stopcock is closed and after 1 min the scale reading is noted. After a further 5 min, the scale reading is noted again. Having equalized the pressures inside the outside-the system, the component is turned on its axis through 90 o and the test is then re
38、peated. It has been found that when cones and sockets complying with the geometric requirements are tested under the above conditions, the rise in pressure in the system does not exceed 10 mm of mercury over a period of 5 min, the total capacity being 1.5 L. For total capacities differing slightly f
39、rom 1.5 L, the corresponding maximum pressure rise is in inverse proportion to the capacity. n Rubber bung or tubing according to size of joint under test & To .vacuum line II n n II n LScaie cwerinq pressure range WMercury U-tube manometer Figure 4. Suitable apparatus for leakage test on conical jo
40、ints - - 6 Publications referred to BS 1134 BS 2045 Preferred numbers IS0 383 Method for the assessment of surface texture Part 1 Method and instrumentation Laboratory glassware - Interchangeable conical ground joints . *Referred to in the foreword only. BS 572 : 1985 Arnd. No. This British Standard
41、, having been prepared under the direction of the Laboratory Apparatus Standards Committee, was published under the authority of the Board of BSI and comes into effect on 28 February 1985. O British Standards Institution, 1985 First published November 1934 First revision March 1950 Second revision S
42、eptember 1960 Third revision February 1985 ISBN O 580 14302 3 British Standards Institution incorporated by Royal Charter, BSI is the independent national body for the preparation of British Standards. It is the UK member of the International Organization for Standardization and UK sponsor of the Br
43、itish National Committee of the International Electrotechnical Commission. Copyright Users of British Standards are reminded that copyright subsists in all BSI publications. No part of this publication may be reproduced in any form without the prior permission in writing of BSI. This does not preclu
44、de the free use, in the course of implementing the standard, of necessary details such as symbols and size, type or Date of issue Text affected grade designations. Enquiries should be addressed to the Publications Manager, British Standards Institution, Linford Wood, Milton Keynes MK14 6LE. The numb
45、er for telephone enquiries is 0908 320033 and for telex 825777. Contract requirements 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, Revision of British Standards British Standards a
46、re revised, when necessary, by the issue either of amendments or of revised editions. It is important that users of British Standards should ascertain that they are in possession of the latest amendments or editions. Information on all BSI publications is in the BSI Catalogue, supplemented each mont
47、h by BSI News which is available to subscribing members of the Institution and gives details of new publications, revisions, amendments and withdrawn standards. Any person who, when making use of a British Standard, encounters an inaccuracy or ambiguity, is requested to notify BSI without delay in o
48、rder that the matter may be investigated and appropriate action taken. The following BSI references relate to the work on this standard: Committee reference LBC/25 Draft for comment 84/52111 DC Committees responsible for this British Standard The preparation of this British Standard was entrusted by
49、 the Laboratory Apparatus Standards Committee (LBC/-) to Technical Committee LBC/25, upon which the following bodies were represented: British Laboratory Ware Association British Lampblown Scientific Glassware Manufacturers Chemical Industries Association Department of Health and Society Security Glass Manufacturers Federation Institute of Medical Laboratory Sciences Institute of Science Technology Royal Society of Chemistry Association Ltd. Amendments issued since publication British Standards Institution - 2 Park Street London WIA 2BS Telephone 01-6
