BS 2021:1980 pdf download.Separating and dropping funnels for laboratory use.
1 Scope and field of application This International Standard specifies details of an internationally acceptable series of glass separating funnels and dropping funnels suitable for general use in laboratories.
2 References ISO 383, Laboratory glassware — Interchangeable conical ground joints. ISO 384, Laboratory glassware — Principles of design and construction of volumetric glassware. ISO 4803, Laboratory glassware — Borosilicate glass tubing 1) .
3 Types and sizes Five types of funnels are specified, of the following sizes: type 1: separating funnel (conical) (see 7.1), nominal capacity 100 – 250 – 500 and 1 000 ml; type 2: separating funnel (pear-shaped) (see 7.2), nominal capacity 50 – 100 – 250 – 500 – 1 000 and 2 000 ml; type 3: separating funnel (Gilson type) (see 7.3), nominal capacity 50 – 100 – 250 – 500 – 1 000 and 2 000 ml; type 4: dropping funnel (cylindrical) (see 7.4), nominal capacity 50 – 100 – 250 – 500 and 1 000 ml; type 5: dropping funnel, graduated (cylindrical) (see 7.5), nominal capacity 50 – 100 – 250 – 500 and 1 000 ml.
4 Material Separating funnels and dropping funnels shall be made from clear glass of suitable chemical and thermal properties. Internal stress and visible defects in the glass shall be reduced to a level sufficient to minimize the possibility of fracture due to thermal or mechanical shock.
5 Construction
5.1 The construction shall be sufficiently robust to withstand normal usage.
5.2 Dropping funnels may be supplied with a ground joint fitted below the stopcock, complying with the requirements of ISO 383. Dropping funnels with a ground joint below the stopcock may be provided with a pressure-equalizing tube placed at the back of the funnel when it is in the position of normal use with the handle of the stopcock on the right. 5.3 The scale of graduated dropping funnels is placed centrally on the cylindrical part of the funnel when it is in the position of normal use with the handle of the stopcock on the right (for graduation and figuring, see ISO 384).
5.3.1 The graduation marks may be figured (see 7.5.1) — in ascending order, or — in both ascending and descending order (see 7.5.3).
5.3.2 Scales may be provided with a longitudinal reference line through the midpoint of the graduation lines to facilitate reading if the funnel is in an inclined position. NOTE The scales of graduated dropping funnels only indicate approximately the volumes of liquid contained. 6 Inscriptions The following inscriptions shall be permanently marked on all separating funnels and dropping funnels: — the nominal capacity, except for graduated dropping funnels; — the symbol cm 3 or the symbol ml; — the maker’s or vendor’s name or mark.BS 2021 pdf download.