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UDC 542.23
IS0
I N TER N AT1 O N AL ORGAN I2 AT1 ON
FOR S TA N DAR DI Z AT I O N
IS0 RECOMMENDATION
R 641
INTERCHANGEABLE SPHERICAL GROUND GLASS JOINTS
1 st EDITION
February 1968
COPYRIGHT RESERVED
The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
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BRIEF HISTORY
The IS0 Recommendation R 641, Interchangeable spherical ground glass joints, was
drawn up by Technical Committee ISO/TC 48, Laboratory glassware and related apparatus,
the Secretariat of which is held by the British Standards Institution (BSI).
Work on this question by the Technical Committee began in 1957 and led, in 1961, to the
adoption of a Draft IS0 Recommendation.
In December 1963, this Draft IS0 Recommendation (No. 714) was circulated to all the
IS0 Member Bodies for enquiry. It was approved by the following Member Bodies:
Argentina Greece Spain
Australia Hungary Switzerland
Austria India Turkey
Belgium Israel U.A.R.
Brazil Italy United Kingdom
Japan U.S.A.
Canada
Chile Netherlands U.S.S.R.
Colombia New Zealand Yugoslavia
Czechoslovakia Poland
One Member Body opposed the approval of the Draft:
France
The Draft IS0 Recommendation was then submitted by correspondence to the IS0
Council, which decided, in February 1968, to accept it as an IS0 RECOMMENDATION.
-2-
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ISO/R 641 - 1968 (E)
IS0 Recommendation R 641 February 1968
INTERCHANGEABLE SPHERICAL GROUND GLASS JOINTS
INTRODUCTION
The purpose of this IS0 Recommendation is to ensure interchangeability between standard
spherical ground glass joints, irrespective of where they are manufactured.
Limiting dimensions for the ground glass zone and the external diameter of adjacent tubing,
which will ensure interchangeability, are given in Table 1, page 5. The finish of the ground
surface is also specified, and this is similar to the finish specified in IS0 Recommendation R 383,
Interchangeable conical ground glass joints.
A conventional designation is adopted, which consists of the code letter “S” in conjunction with
the approximate spherical diameter of the joint in millimetres. The bore diameter which may be
employed with each size of joint is controlled, for the purposes of this IS0 Recommendation,
only by the maximum diameter at the narrow end of the ground zone.
A convenient leakage test, to be carried out on ungreased joints, is described in Appendix Y,
but this does not form an integral part of this IS0 Recommendation. In Appendix Z are listed,
for convenience, the size designations of the joints specified in the British and U.S.A. standards
which correspond to, or are interchangeable with, the joints listed in this IS0 Recommendation.
While reference is made, in this IS0 Recommendation, only to glass joints, these having come
into general use, it is not thereby intended to exclude the development of joints made of other
materials, which should be manufactured to the same dimensions.
1. SCOPE
This IS0 Recommendation covers the essential geometric requirements for interchangeability in
relation to a series of ground glass joints for laboratory use.
2. NOMINAL SPHERICAL GROUND JOINT DIAMETER
The diameter of the ground spherical zone should be in accordance with the dimensions specified
in Table 1, columns 2, 3 and 4. These tolerances ensure that the diameter of the inner component
(or ball member) is not greater than the nominal diameter and that the diameter of the outer
component (or cup member) is not less than the nominal diameter.
3. DIMENSIONS
The diameter at the wide end of the ground zone should not be less than the corresponding
dimension given in Table 1, column 5, and the diameter at the narrow end of the ground zone
should not be greater than the corresponding dimension given in Table 1, column 6. The
I
relationship of the dimensions is illustrated in Figure 1, page 4.
l
I
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IÇO/R 641 - 1968 (E)
Extei-na1 diameter of adjacent tubing
x
lnner component (ball)
Diameter at narrow end
of ground zone
Diameter at wide end of ground zone
0 C
7
I
l
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ISO/R 641 - 1968 (E)
4. DIAMETER OF TüBING
The external diameter of tubing adjacent to the joint should not exceed the dimensions given in
Table 1, column 7.
NOTE. - It is important to limit the external diameter of the tubing in order to facilitate interchangeability of
clamps.
TABLE 1 - Dimensions and tolerances of spherical ground joints
Dimensions in millimetre
5 6~7
1 ~ 2 314
I Spherical diameter
Minimum Maximum Maximum
diameter diameter external
Tolerance Tolerance
Sue
at wide end at narrow diameter
Nominal on inner on outer
designation
of ground end of of adjacent
dimension component
component
zone ground zone tubing
@all) (C
...