Test Sieves of Perforated Metal Plate- Technical Requirements and Testing
Technical requirements and corresponding test methods for test sieves of perforated metal plate. It applies to the following test sieves
- Round holes perforated plate sieve, with hole sizes from 1 mm up to 125 mm,
- Square holes perforated plate sieve, with hole sizes from 4 mm up to 125 mm.
Perforated metal plate Requirements
Hole size, tolerances, and plate thickness.
The tolerances on the individual size of holes and the selection of pitches shall be as specified in Table 1 (apply to both round and square holes).
| Nominal sizes of holes, w | Tolerances on individual size of hole ± |
Pitch, p | ||||
|---|---|---|---|---|---|---|
| Principal sizes | Supplementary sizes | Preferred sizes | Permissible range of choice | |||
| R 20/3 | R 20 | R 40/3 | pnom | Pmax | pmin | |
| 125 | 125 | 125 | 1 | 160 | 184 | 143 |
| 112 | 0.95 | 140 | 161 | 126 | ||
| 106 | 0.9 | 132 | 152 | 119 | ||
| 100 | 0.85 | 125 | 144 | 113 | ||
| 90 | 90 | 90 | 0.8 | 112 | 129 | 101 |
| 80 | 0.7 | 100 | 115 | 90 | ||
| 75 | 0.7 | 95 | 109 | 85 | ||
| 71 | 0.65 | 90 | 103 | 81 | ||
| 63 | 63 | 63 | 0.6 | 80 | 92 | 72 |
| 56 | 0.55 | 71 | 82 | 63.5 | ||
| 53 | 0.55 | 67 | 77 | 60 | ||
| 50 | 0.55 | 63 | 72.5 | 56.5 | ||
| 45 | 45 | 45 | 0.5 | 56 | 64.5 | 50.5 |
| 40 | 0.45 | 50 | 57.5 | 45 | ||
| 37.5 | 0.45 | 47.5 | 54.6 | 42.5 | ||
| 35.5 | 0.4 | 45 | 51.7 | 40.5 | ||
| 31.5 | 31.5 | 31.5 | 0.4 | 40 | 46 | 36 |
| 28 | 0.35 | 35.5 | 40.8 | 31.8 | ||
| 26.5 | 0.35 | 33.5 | 38.5 | 30 | ||
| 25 | 0.35 | 31.5 | 36 | 28.5 | ||
| 22.4 | 22.4 | 22.4 | 0.3 | 28 | 32.2 | 25.5 |
| 20 | 0.3 | 25 | 29 | 22.5 | ||
| 19 | 0.29 | 23.6 | 27.1 | 21.3 | ||
| 18 | 0.28 | 22.4 | 25.8 | 20.2 | ||
| 16 | 16 | 16 | 0.27 | 20 | 23 | 18 |
| 14 | 0.26 | 18 | 20.7 | 16 | ||
| 13.2 | 0.25 | 17 | 19.5 | 15.1 | ||
| 12.5 | 0.24 | 16 | 18.4 | 14.3 | ||
| 11.2 | 11.2 | 11.2 | 0.23 | 14 | 16.1 | 12.6 |
| 10 | 0.21 | 12.6 | 14.5 | 11.3 | ||
| 9.5 | 0.21 | 12.1 | 13.8 | 10.2 | ||
| 9 | 0.2 | 11.6 | 13.3 | 9.8 | ||
| 8 | 8 | 8 | 0.19 | 10.4 | 12 | 9.2 |
| 7.1 | 0.18 | 9.4 | 10.8 | 8 | ||
| 6.7 | 0.17 | 8.9 | 10.2 | 7.5 | ||
| 6.3 | 0.17 | 8.5 | 9.8 | 7.2 | ||
| 5.6 | 5.6 | 5.6 | 0.15 | 7.7 | 8.9 | 6.6 |
| 5 | 0.14 | 6.9 | 7.9 | 5.9 | ||
| 4.75 | 0.14 | 6.6 | 7.6 | 5.6 | ||
| 4.5 | 0.14 | 6.3 | 7.2 | 5.3 | ||
| 4 | 4 | 4 | 0.13 | 5.8 | 6.7 | 4.9 |
| 3.55 | 0.12 | 5.2 | 6 | 4.4 | ||
| 3.35 | 0.11 | 5 | 5.7 | 4.2 | ||
| 3.15 | 0.11 | 4.7 | 5.3 | 3.9 | ||
| 2.8 | 2.8 | 2.8 | 0.11 | 4.35 | 5 | 3.6 |
| 2.5 | 0.11 | 3.9 | 4.5 | 3.3 | ||
| 2.36 | 0.11 | 3.75 | 4.3 | 3.2 | ||
| 2.24 | 0.1 | 3.6 | 4.1 | 3.1 | ||
| 2 | 2 | 2 | 0.09 | 3.3 | 3.8 | 2.8 |
| 1.8 | 0.08 | 3.1 | 3.6 | 2.7 | ||
| 1.7 | 0.08 | 3 | 3.4 | 2.5 | ||
| 1.6 | 0.08 | 2.75 | 3.2 | 2.3 | ||
| 1.4 | 1.4 | 1.4 | 0.08 | 2.6 | 3 | 2.2 |
| 1.25 | 0.08 | 2.45 | 2.9 | 2.1 | ||
| 1.18 | 0.07 | 2.4 | 2.7 | 2 | ||
| 1.12 | 0.07 | 2.22 | 2.5 | 1.8 | ||
| 1 | 1 | 1 | 0.07 | 2 | 2.3 | 1.7 |
| Note: the lower limit of the nominal size of square holes is 4 mm. | ||||||
| Nominal sizes of holes w |
Plate thickness | ||
|---|---|---|---|
| Preferred thickness | Permissible range of choice | ||
| Max. | Min. | ||
| 125 to 50 | 3 | 3.5 | 2 |
| 45 to 16 | 2 | 2.5 | 1.5 |
| 14 to 8 | 1.5 | 2 | 1 |
| 7.1 to 1.7 | 1 | 1.5 | 0.8 |
| 1.6 to 1.0 | 0.6 | 1 | 0.5 |
Arrangement of holes
Round and square holes in perforated metal plates in test sieves shall be arranged in straight or staggered rows.
Sieves with hole sizes 4 mm and above shall have an unperforated margin. Partial holes are not permitted. The unperforated margin is influenced by the hole size, pitch, and manufacturing method, resulting in different margin widths.
Figure 1: Arrangement of square and round holes in test sieves
Material of plate
Material of perforated metal plate may be brass or stainless steel.
Test methods of perforated test sieves
Tolerances on individual size of hole for every hole in the perforated metal plate in a test sieve. Measure the hole sizes using appropriate equipment with a precision of reading of 20 μm or 1/4 of the tolerance concerned, whichever is greater.
Test 1 — Visual examination of general condition
View the perforated metal plate against a uniformly illuminated background. If obvious deviations from uniformity of appearance are found, for example partial holes (4 mm and larger), the sieve is unacceptable.
Test 2 — Measurement of size of hole and pitch
Measure the hole size on the centre lines of square holes and on the diameter of round holes according to Table 3.
| Nominal sizes of holes w mm |
Process for compliance and inspection | Process for calibration |
|---|---|---|
| 125 to 22.4 | All (max. 25 in larger sieves with diameter more than 200 mm) | All (max. 50 in larger sieves with diameter more than 200 mm) |
| 20 to 4 | 2 × 15 | 2 × 30 |
| 3.55 to 2.24 | 2 × 20 | 2 × 40 |
| 2 to 1.6 | 2 × 25 | 2 × 50 |
| 1.4 to 1 | 2 × 40 | 2 × 80 |
Measure the dimensions of the holes and the pitches, p, over any selected area of the plate, along two straight lines and different directions, each line being at least 150 mm in length and including at least eight holes in each direction.
If the dimension of any hole exceeds the tolerance, the sieve is unacceptable.
If the minimum number of holes prescribed for examination is not available in the plate, check all the holes in the sieve.
Figure 2: Example of hole configuration for measurement of up to 20 holes