Test Sieves: Part-II Perforated Plate Test Sieves
1985 Edition

IS 460 Part 2 (1985) permits the use of specific materials for both perforated plates and sieve frames, as outlined in Table 1 (Clause 3.1). These include brass sheets conforming to IS 410-1977, stainless steel sheets as per IS 6911-1972, galvanized steel sheets under IS 277-1972, and electroplated steel sheets following IS 513-1973. Mild steel is explicitly not allowed. Manufacturers must declare material grades upon purchaser’s request. These materials ensure longevity, corrosion resistance, and precise sieving performance.

The standard specifies nominal aperture sizes for round holes ranging from 140 mm to 200 mm with tolerances between ±1.10 mm and ±1.55 mm. These non-ISO sizes are permitted only when equivalent ISO sizes are not available. Tolerances apply to individual aperture diameter measurements (Clause 3.2.2). This ensures that apertures maintain dimensional accuracy essential for reliable particle size separation.

According to IS 460 Part 2, round holes are arranged such that their centers lie at the corners of equilateral triangles, creating a triangular pitch pattern. Square holes are aligned in rows with their midpoints positioned at the vertices of squares, forming a square pitch layout (Clause 3.5.1). All holes must be uniformly and cleanly punched without partial apertures after mounting to maintain sieving consistency and efficiency.

The standard recommends using a 200 mm round frame for apertures up to 25 mm. For larger apertures, 300 mm frames that may be round or square are suggested. For very large apertures exceeding 25 mm, 450 mm frames, either round or square, are advised. Key dimensional parameters include top internal diameter/length, bottom external diameter/length, minimum frame thickness, effective sieving surface, and depths from edges to sieving surface (Clause 4.2, Table 4). Frames must be nestable to facilitate stacking.

Calibration testing under IS 460 Part 2 is not mandatory by default. Its execution depends entirely on purchaser specifications and must be clearly requested in the enquiry or order documentation (Clauses 8.1 and 9.1). The purchaser should explicitly state whether calibration is required to ensure that the supplier performs the appropriate verification according to IS 460 Part 3 or related calibration standards.

Non-ISO aperture sizes are permitted only for round holes greater than 125 mm in diameter, and solely when the closest ISO sizes are unavailable (Clause 3.2.3). The allowable non-ISO aperture sizes include 140 mm, 160 mm, 180 mm, and 200 mm with specified tolerances. This conditional acceptance ensures availability without compromising sieving accuracy.

IS 460 Part 2 mandates that sieving surfaces, frame receivers, and covers must have smooth finishes to prevent particle lodging and facilitate cleaning (Clause 5.1). Seals between the frame and sieving medium must be tight to avoid material entrapment. Surfaces in contact with samples should not have lacquer or coatings to prevent contamination. Additionally, perforated plates must feature uniformly punched, clean holes without irregular edges to maintain consistent sieving performance.