|
IS0
I N T ER N AT I ON AL ORGAN I Z AT I ON
FOR STA N DA RD IZ AT1 O N
IS0 RECOMMENDATION
R 383
INTERCHANGEABLE CONICAL GROUND GLASS JOINTS
1st EDITION
September 1964
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.
---------------------- Page: 1 ----------------------
BRIEF HISTORY
The IS0 Recommendation R 383, Interchangeable Conical Ground Glass Joints, was drawn
up by Technical Committee ISO/TC 48, Laboratory Glassware and Related Apparatus, the Secre-
tariat of which is held by the British Standards Institution (BSI).
Work on this question by the Technical Committee began in 1950 and led, in 1960, to the
adoption of a Draft IS0 Recommendation.
In April 1960, this Draft IS0 Recommendation (No. 346) was circulated to all the IS0
Member Bodies for enquiry. It was approved, subject to a few modifications of an editorial
nature, by the following Member Bodies :
Australia
Germany Rom ani a
Austria
Greece Spain
Belgium India Sweden
Canada Israel United Kingdom
Chile Japan U.S.A.
Colombia Netherlands U.S.S.R.
Czechoslovakia
New Zealand
France Poland
One Member Body opposed the approval of the Draft
Italy.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0
Council, which decided, in September 1964, to accept it as an IS0 RECOMMENDATION.
-2-
---------------------- Page: 2 ----------------------
I
ISO/R 383 - 1964 (E)
IS0 Recommendation R 383 September 1964
INTERCHANGEABLE CONICAL GROUND GLASS JOINTS
INTRODUCTION
The purpose of this IS0 Recommendation 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 of the following requirements should be adequately
specified, including appropriate tolerances :
(4 Taper,
(b) Large end diameter,
c
(c) Length of ground zone,
(d) Surface finish.
The nominal dimensions listed below are based on the series of joints already widely used in many
countries; in particular, the series of large end diameters represents the nearest acceptable
compromise to the R 40/3 series of preferred numbers (5.3 . 100) laid down in IS0 Recommen-
dation R 3, Preferred Numbers - Series of Preferred Numbers.
From the practical point of view, and especially because of the difficulty of carrying out precise
measurements on the ground portions of the finished joints, it is desirable to apply a gauging
system which allows rapid checking of the essential dimensions. The definition of these dimen-
sions in section 5 is an integral part of this IS0 Recommendation, but the system of gauging
described in Annex A, while it has been proved in practice as fully satisfactory, is not the
only one which can be applied for the purpose.
The leakage test described in Annex B is one which is commonly used for testing joints, but its
inclusion in this IS0 Recommendation is not intended to preclude the use of other tests which
may be found more convenient for particular purposes. Attention is specifically drawn to the
method of pneumatic gauging. *
1. SCOPE
This IS0 Recommendation covers the essential geometric requirements for interchangeability
in relation to four series of conical ground glass joints for laboratory use.
2. TAPER
The taper of the joints should be such as to give one increment on diameter for ten
increments on axial length, with a tolerance of -& 0.006 on the diameter increment, i.e. a taper of
(1.00 & 0.006)/10.
* This method is described in Lnborutory Practice, March 1958, Vol. 7, No. 3, “Pneumatic gauging applied to standard
ground glass joints”, by I.C.P. Smith.
3
---------------------- Page: 3 ----------------------
ISO/R 383 - 1964 (E)
3. LARGE END DIAMETERS
The following series of large end diameters should be adopted:
5 - 7.5 - 10- 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, should be calculated from the formula
l=kdd
where k = a constant,
d = large end diameter, expressed in millimetres,
off to the nearest whole number.
the calculated length being rounded
The four series of joints listed in Table 1 are obtained by using the values 2, 4, 6 and 8 for the
constant k.
TABLE 1. - Series of joints
Dimensions in millimetres
Length of ground zone Length of ground zone
Large end Large end
Y
diameter
diameter
k2 series k4 series k6 series 1 k8 series k2 series
k4 series k6 series lc8 series
5 9 34.5 12 23 35 47
7.5 11 40 13 38
10 13 19 25 45 13 40
12.5 14 21 28 50 14 42
14.5 15 23
30 60 46
18.8 9 17 71 51
85
21.5 19 55
24 10 20 100
60
29.2 11 22
5. TOLERANCES ON DIAMETER AND LENGTH
The diameter and length of the ground zone should 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 the upper and lower
edges of the ground surface fall within the zones of height h, and h, respectively, the values of
d, I, h, and h, for any particular joint size being taken
...