1、INTERNATIONAL STANDARD IS0 4785 First edition 1997-05-01 ANSI Internat X30-c See Laboratory glassware - Straight-bore glass stopcocks for general purposes Verrerie de laboratoire - Robinets en verre B al a=400net; p=iso; o=isocs; s=central Printed in Switzerland ii INTERNATIONAL STANDARD 0 IS0 IS0 4
2、785:1997(E) Laboratory glassware - Straight-bore glass stopcocks for general purposes 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 larg
3、e end diameter and length of the ground zone. It is recommended that, in national standards, only one of the series should be specified. NOTE - Annex A lists additional International Standards for other general-purpose laboratory glassware. 2 Normative references The following standards contain prov
4、isions which, through reference in this text, constitute 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 p
5、ossibility of applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 719:1985, Glass - Hydrolytic resistance of glass grains at 98C - Method of test and classification. IS0 3585: 1991, Borosilicate
6、 g/ass 3.3 - Properties. IS0 4803:1978, Laboratory glassware - 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 + 0,006 on the diameter increment i.e. a taper o
7、f (I f 0,006)/l 0. NOTES 1 This tolerance is in agreement with the relevant requirement of IS0 383. Annex B in IS0 383:1976 describes a leakage test with air which may be used to check the tightness of the ground zone. 2 Actual manufacturing techniques normally result in a tighter tolerance than tha
8、t given above, but owing to the lack of experimental evidence it is not yet possible to reduce the specified value. 3.2 The centreline average height of the ground surface shall not exceed 1 urn and should preferably be less than 0,5 urn. 1 IS0 4785:1997(E) 0 IS0 NOTE- The “centreline average height
9、” of the ground surface is the average value R, of the surface roughness as defined in IS0 468. 4 Dimensions and series of sizes 4.1 The nominal diameters of series I stopcocks shall be as follows (given in millimetres): 1 - 1,5-2,5-4-6- 10 NOTE - This is the R 5 series of preferred numbers. 4.2 The
10、 nominal diameters of series II stopcocks shall be as follows (given in millimetres): l-1,5-2-3-4-5-6-8-10 4.3 The dimensions 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
11、 Side arms The side arms shall be fused to the barrel so as to enable a pin of thickness 0,8 times the nominal bore to fit 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 bor
12、osilicate glass 3.3, tubes in accordance with IS0 4803 should be used. 6 Material 6.1 Stopcocks should preferably be made from borosilicate glass 3.3 in accordance with IS0 3585. When tested according to the procedure and classification given in IS0 719, the glass shall comply with the requirements
13、of class HGB3 or better. The glass should be as free as possible from visible defects and reasonably free from internal stress 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
14、 key may be solid or hollow at the manufacturers discretion. The key may project slightly beyond the base of the ground zone and 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
15、be sufficiently robust to withstand normal usage. 2 0 IS0 IS0 4785:1997(E) Figure 1 - Straight-bore stopcock, general appearence - w Figure 2 - Test according to clause 5 Example for positioning a retaining device (if fit ted) Figure 3 - Assembled stopcock 3 IS0 4785:1997(E) 8 Dimensions The dimensi
16、ons shall be as given in tables 1 to 3. 9 Designation For convenience of reference to stopcocks complying with the requirements of this International Standard, the use of a designation is recommended, consisting of the following dimensions, expressed in millimetres: - nominal bore diameter (e.g. 41,
17、 and - large end diameter of the ground zone (e.g. 18,8), and - the number of this International Standard. EXAMPLE: Stopcock IS0 4785,4 - 18,8 10 Marking The size of the large end diameter of the ground zone according to table 2 shall be marked on the barrel of each stopcock in such a way as to be p
18、ermanent under normal conditions of use: EXAMPLE: 18,8 Table 1 - Dimensions and tolerances of the ground zone Dimensions in millimetres d, “ I, * 2 7,5+ 0,008 22 11 +0,215 8 +0,008 20 10 +0,215 10 +0,008 25 12,5+ 0,215 12,5+0,01 28 14 +0,215 13,5+ 0,Ol 30 15 +0,215 14,5+ 0,Ol 30 15 +0,215 18,8+0,015
19、 38 19 +0,26 II 19 +. 0,015 I 40 I 20 +0,26 II 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 “The tolerances are in agreement with the relevant requirements of IS0 383. *) As I2 is the essential dimension, I, is left without t
20、olerances. IS0 4785:1997(E) Table 2 - Nominal dimensions of ground zone and bore diameter Dimensions in millimetres 5 IS0 4785:1997(E) Table 3 - Recommended dimensions for side arms Dimensions in millimetres I min. I Series I I Series II II 7 I 115 I 1 II lr 7 I 100 I 1 I II 8 100 I,5 7 115 1 8 I 11
21、5 I I,5 II 8 115 2 9 100 2,5 10 a10 4 IO 115 3 IO I 115 I 4 II 13 120 6 12 115 5 12 130 6 14 130 8 18 120 10 17 140 10 6 IS0 4785:1997(E) Annex A (informative) Bibliography I IS0 383:1976, Laboratory glassware - Interchangeable conical ground joints. 2 IS0 384:1978, Laboratory glassware - Principles
22、 of design and construction of volumetric glassware. 31 IS0 468:1982, Surface roughness - Parameters, their values and genera/ rules for specifying requirements. 141 IS0 641 :1975, Laboratory glassware - Interchangeable spherical ground joints. 151 IS0 1773: 1997, Laboratory glassware - Narrow-necke
23、d boiling f/asks. 61 IS0 3819:1985, Laboratory glassware - Beakers. 7 IS0 4142:1997, Laboratory glassware - Test tubes and culture tubes. 181 IS0 4796:1977, Laboratory glassware - Bottles. 191 IS0 4797:1981, Laboratory glassware - F/asks with conical ground joints. IO IS0 4798:1997, Laboratory glass
24、ware - Filter funnels. 1 I IS0 4799:1978, Laboratory glassware - Condensers. 121 IS0 4800: 1977, Laboratory glassware - Separating funnels and dropping funnels. I 31 IS0 6556: 1981, Laboratory glassware - Filter f/asks. 7 IS0 4785:1997(E) ICS 71.040.20 Descriptors: laboratory equipment, laboratory glassware, stopcocks, specifications, dimensions, designation. Price based on 7 pages
