Test sieves

The sieve test is probably still the most commonly used sizing technique both to characterize particulate distributions and separate them into fractions on the... 

Figure 1.13 Sieve test method for particle size analysis...

Sieving Test.—This is usually carried out with a sieve of silk about 20 cm. in diameter and with 46 meshes per cm. 50 grams of the product to be examined are placed on the sieve, which is moved backwards and forwards by means of two wooden handles fitted at opposite sides inside a rectangular wooden framework the sieving should not last more than 10 minutes. The residue on the sieve is weighed and calculated as a percentage and the fine flour determined by difference. 

Sieving test. No appreciable residue should be left on a sieve with 40 meshes per cm., except m the case of granular flours. 

The requirement for this test should be deleted. Consideration should be given to introducing the dry sieve test, as used for FAO specifications for dustable powder (DP) formulations (4). 

The sieve tests (wet and dry) should be conducted after heat stability treatment according to CIPAC methods MT 59, MT 167 and MT 170 (5). In case of unacceptable results, sieving should be determined without heat treatment. 

Sieving test after heat stability treatment (WHO/M/4.R1)... 

The physical and chemical characteristics of preparations via parameters (e.g., explosive properties, oxidizing properties, flashpoint and other indications of flammability, acidity/alkalinity and pH, surface tension, density, wettability, suspensi-bility, dilution stability, dry and wet sieve test, particle size distribution and other properties of the formulation) and the corresponding methods have to be determined and reported in detail [46]. 

Procedures for test sieving, both wet and dry, are prescribed in standard specifications (ISO 2591, 1989 BS 1796, 1990). Methods for the analysis of sieve test data are described in section 2.14.4. 

Many different forms of graphical expression may be employed, and the use and applicability of some of these methods are demonstrated below with reference to the results of a sieve test. The graphical procedures described, however, are applicable, with suitable nomenclature changes, to all methods of particle size analysis. The sieve test data in Table 2.14 are recorded in three different ways, viz. the percentage by mass of the fractions retained on each sieve, and the cumulative mass percentages of oversize and undersize material. 

Table 2.14. Sieve test data used for the construction of Figures 2.15 to 2.18...

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