Test Sieves: Part-III Methods of Examination of Apertures of Test Sieves

IS 460 Part 3 - Scope & Key Specifications Summary

• Scope: Covers calibration tests for woven wire cloth test sieves used in particle size analysis.
• Measurement of Apertures (Clause 2.1.4):
  • Aperture width measured separately in warp and weft directions.
  • Tolerances X, Y, Z per Part 1 of IS 460 apply.
  • Use optical projector or microscope with coordinate measuring table.

Key Table: Number of Apertures to be Measured (Table 1)

• Fields are evenly spread; no two fields crossed by the same wire.
• Masks for measurement: Fig. 2 shows 10-field and 15-field masks.

Measurement Procedure (Clause 3.1)

• Aperture width measured in multiple fields over sieve area.
• Use masks with max diameter = min effective sieve diameter.
• Measure apertures consecutively in warp and weft directions.

flowchart LR
    A[Start: Select Sieve] --> B[Choose Mask (10 or 15 fields)]
    B --> C[Measure Apertures in Warp Direction]
    B --> D[Measure Apertures in Weft Direction]
    C --> E[Record Consecutive Aperture Widths]
    D --> E
    E --> F[Compare with Tolerances X, Y, Z]
    F --> G{Within Limits?}
    G -->|Yes| H[Accept Sieve]
    G -->|No| I[Reject or Recalibrate]

Summary: IS 460 Part 3 defines detailed procedures and minimum sample sizes for aperture measurement in woven wire test sieves, ensuring accurate sieve calibration for particle size analysis

IS 460 Part 3: Acceptance Test Key Points

1. Acceptance Test Scope (Clause 1.2)

• Determines conformity of sieve apertures per Part 1 or 2.
• Calibration test needed for master sieves or detailed info.

2. Pitch Measurement (Clause 2.2.6)

• Pitch of apertures checked simultaneously with aperture size measurement.

3. Aperture Measurement (Clause 2.1.4)

• Measure apertures in warp and weft directions.
• Use optical projector/microscope with coordinate measuring table.
• Check tolerances X, Y, Z as per Part 1.

4. Calibration Test - Aperture Measurement (Clause 3.1 & Table 1)

• Measure in fields evenly spread over sieve.
• No two fields crossed by same wire.
• Use masks (Fig. 2) for field selection.

Summary Diagram: Measurement Process

flowchart TD
    A[Start Acceptance Test] --> B[Measure Aperture Size & Pitch]
    B --> C{Is Sieve Master?}
    C -- No --> D[Acceptance Test Complete]
    C -- Yes --> E[Perform Calibration Test]
    E --> F[Select Fields Using Masks]
    F --> G[Measure Consecutive Apertures per Table 1]
    G --> H[Check Tolerances X, Y, Z]
    H --> I[Report Results]

Use Table 1 and masks (Fig. 2) to ensure statistically valid aperture measurements.

IS 460 Part 3: Wire Cloth Test Sieve - Key Specifications

• Wire Cloth Test Sieve is used for particle size analysis in materials like aggregates and powders.

Key Specifications (as per IS 460 Part 3 & related IS standards):

Important Formula:

• Mesh Opening (mm) = 25.4 / Mesh Number

  Where Mesh Number = number of openings per inch.

Additional Notes:

• Test sieves must comply with IS 460 Part 1 for general requirements.
• Sieve aperture size and wire diameter are standardized to ensure reproducibility.
• Periodic calibration and inspection are recommended.

flowchart LR
  A[Raw Material Sample] --> B[Wire Cloth Test Sieve]
  B --> C[Particle Size Separation]
  C --> D[Analysis & Quality Control]

For detailed mesh sizes and wire diameters, refer to IS 460 Part 1 tables.

Inspection Eligibility of Apertures (IS 460 Part 3)

• Measurement Directions: Apertures are measured along three tolerances X, Y, Z in both warp and weft directions (Clause 2.1.4).
• Measurement Tools: Use optical projectors, microscopes, or coordinate measuring tables for precise aperture dimensioning.
• Oversize Apertures: Apertures deviating by ~10% from average width are visually detectable (Clause 2.1.5). Any aperture exceeding the maximum permissible deviation X renders the sieve unacceptable.
• Inspection Scope: Every aperture in the perforated plate sieve is eligible for inspection (Clause 2.2.1).
• Inspection Procedure:
  • Start with a general survey.
  • Proceed to detailed scrutiny of individual apertures.
  • Measure apertures for compliance with tolerances.
  • If minimum holes for sampling (Clause 2.2.5) are unavailable, inspect all apertures (Clause 2.2.2).

Key Specification Summary

flowchart TD
    A[Start Inspection] --> B[General Condition Survey]
    B --> C[Scrutinize Individual Apertures]
    C --> D{Are min. holes for sampling available?}
    D -- Yes --> E[Measure sample apertures for X, Y, Z tolerances]
    D -- No --> F[Measure all apertures]
    E --> G{Any aperture oversize > X?}
    F --> G
    G -- Yes --> H[Sieve Unacceptable]
    G -- No --> I[Sieve Acceptable]

This ensures compliance with aperture size tolerances and sieve quality per IS 460 Part 3.

IS 460 Part 3 — Examination Procedure for Apertures of Test Sieves

Key Points from Clauses 2.1.2 & 2.2.2:

• Examination Stages:

  1. General condition survey of the sieve.
  2. Methodical scrutiny of individual apertures.
  3. Measurement of aperture size to check compliance with tolerances.

• Number of apertures to examine:

  • If sieve has ≤ 20 apertures, all apertures must be measured.
  • If more than 20, a minimum number of holes in one or two directions (see clause 2.2.5) are checked.
  • If minimum holes are not available, all holes must be checked.

Typical Procedure Summary:

Tolerances:

• Aperture size must comply with IS 460 tolerances (refer to relevant tables in IS 460 Part 1/2).

Example: Minimum Number of Holes to Examine (Clause 2.2.5)

flowchart TD
    A[Start: General Condition Survey] --> B[Scrutinize Individual Apertures]
    B --> C{Number of apertures ≤ 20?}
    C -- Yes --> D[Measure All Apertures]
    C -- No --> E[Measure Minimum Number of Holes]
    E --> F{Minimum holes available?}
    F -- Yes --> G[Measure Minimum Holes]
    F -- No --> H[Measure All Holes]
    D & G & H --> I[Check Compliance with Tolerances]
    I --> J[End]

Summary: Follow a staged examination from general condition to detailed aperture measurement. Measure all apertures if ≤ 20; otherwise, measure a prescribed minimum

IS 460 Part 3 Key Points: General Condition of Wire Cloth

1. Examination of Wire Cloth (Clause 2.1.3)

• View sieve cloth against a uniformly illuminated background.
• Reject if:
  • Weaving defects (loose wires, creases, wrinkles) are visible.
  • Blinded apertures (closed openings) away from the periphery exist.
• Partial apertures near the periphery are acceptable.

2. Calibration Tests for Aperture Measurement (Clause 3.1)

• Measure aperture width in multiple fields evenly spread over the sieve.
• No two fields should be crossed by the same wire.
• Use masks (Fig. 2) sized to the minimum effective diameter of the sieving surface.
• Measure apertures in both warp and weft directions.

3. Number of Apertures to Measure (Table 1)

Refer to the full table for intermediate sizes.

4. Masks for Measurement (Fig. 2)

• Ten-Field Mask for larger apertures.
• Fifteen-Field Mask for smaller apertures.

flowchart LR
    A[Start] --> B[View wire cloth against illuminated background]
    B --> C{Any defects?}
    C -- Yes --> D[Reject sieve]
    C -- No --> E[Measure apertures using masks]
    E --> F[Check number of fields & apertures per Table 1]
    F --> G[Accept sieve if all criteria met]

Summary: Ensure wire cloth is defect-free visually, then measure apertures systematically across multiple fields using masks, following the minimum counts in Table 1 for calibration accuracy.

IS 460 Part 3 (1985) – Measurement of Apertures: Key Points

1. Measurement Directions & Tolerances

• Aperture measurements are taken in three tolerances X, Y, Z (see Part 1).
• Measurements are done separately in warp and weft directions.
• Instruments: Optical projector, microscope + coordinate measuring table.

2. Aperture Size Measurement

• Identify oversize apertures: Apertures deviating by ~10% from average are visually detectable.
• Oversize apertures exceeding tolerance X render the sieve unacceptable.
• Measure average aperture size over at least 10 apertures in each direction at 2 widely spaced positions.
• If results vary or contradict Table 2 (Part 1), measure at 3 more positions.
• The combined average from all positions must lie within prescribed limits.

3. Pitch Measurement

• Pitch (distance between apertures) is checked simultaneously with aperture size tests.

Summary Table (Conceptual)

flowchart LR
    A[Start] --> B[Measure apertures in warp & weft]
    B --> C{Any aperture > 10% deviation?}
    C -- Yes --> D[Measure oversize apertures individually]
    D --> E{Oversize > tolerance X?}
    E -- Yes --> F[Reject sieve]
    E -- No --> G[Continue]
    C -- No --> G
    G --> H[Measure average aperture size at 2 positions]
    H --> I{Results consistent?}
    I -- No --> J[Measure at 3 more positions]
    J --> K[Calculate overall average]
    I -- Yes --> K
    K --> L{Average within limits?}
   

IS 460 Part 3 (1985) — Measurement of Oversize Apertures

Key Points & Procedures:

• Detection:

  • Visually inspect all openings carefully for oversize apertures (Clauses 2.1.5, 2.2.4).
  • Apertures deviating by ~10% from average are noticeable to skilled observers.

• Measurement Tools:

  • Coarser sieves: Engineer's calliper, limit gauge, segmental gauge.
  • Finer sieves: Optical magnification (microscope, projector) combined with coordinate measuring table (Clause 2.1.4).

• Tolerance Checks:

  • Measure apertures in warp and weft directions separately.
  • Check against tolerances X, Y, Z as per Part 1 of IS 460 (Clause 2.1.4).
  • If any aperture exceeds max permissible deviation X, sieve is rejected.

• Average Aperture Size:

  • Measure at least 10 apertures in each direction at minimum two widely dispersed positions (Clause 2.1.7).
  • If inconsistent, measure at 3 more positions.
  • Average of all measurements must lie within prescribed limits.

Summary Table (Conceptual)

flowchart TD
    A[Start Inspection] --> B{Visual Check for Oversize Apertures}
    B -->|Yes| C[Measure Oversize Apertures]
    B -->|No| D[Measure Average Aperture Size]
    C --> E{Is Oversize > Max Tolerance X?}
    E -->|Yes| F[Reject Sieve]
    E -->|No| D
    D

Use of Limit Gauges as per IS 460 Part 3

Key Specifications:

• Measurement of Holes (Clause 2.2.5):

  • Check individual holes for compliance with tolerances.
  • Square holes: measured at mid-section in two perpendicular directions.
  • Round holes: measured across various diameters.
  • Measurement lines:
    • Two straight lines ≥100 mm, ≥10 holes (5 per direction), at 90° or 60° for round holes.
    • For square holes, alternatively along a diagonal line ≥150 mm with ≥8 holes.
  • Tools: Calipers, tapered plate gauges, segmental plain limit plug gauges, optical projection.

• Limit Gauge Testing (Clause 2.1.6.1):

  • Use a tolerance band gauge (scale form) or individual gauges for coarse sieves.
  • Observe at least 100 apertures in each direction.
  • Example tolerance band gauge for 355 μm sieve cloth at 50x magnification:

• Measurement of Apertures (Clause 2.1.4):

  • Measure tolerances X, Y, Z in warp and weft directions.
  • Use optical projector or microscope with coordinate measuring table.

• For Apertures >3.35 mm (Clause 3.1.1):

  • Test at least 20 apertures in each direction.
  • If ≤20 apertures total, measure all.

Summary Table for Hole Checking

Visual Concept of Limit Gauge Use

flowchart LR
    A[Select

IS 460 Part 3: Measurement of Average Aperture Size

Key Specifications & Procedure:

• Sample size: Measure at least 10 apertures in each direction (warp & weft) at 2 widely dispersed positions on the cloth.
• If results differ in tolerance bands or contradict Table 2 (Part 1), measure at 3 additional positions.
• The average aperture size from all 5 positions must lie within prescribed limits.

Measurement Details:

• Measure apertures separately in warp and weft directions for tolerances X, Y, Z (see Part 1).
• Use optical projector, microscope + coordinate measuring table for accuracy.
• Oversize apertures (±10% deviation) must be individually measured.
• If any aperture exceeds maximum permissible deviation X, sieve is rejected.

Summary Table (Conceptual):

flowchart TD
    A[Start: Select sieve cloth] --> B[Measure 10 apertures in warp & weft at 2 positions]
    B --> C{Are results consistent?}
    C -- Yes --> D[Calculate average aperture size]
    C -- No --> E[Measure 10 apertures at 3 more positions]
    E --> F[Calculate average of all 5 positions]
    D --> G{Average within tolerance?}
    F --> G
    G -- Yes --> H[Sieve accepted]
    G -- No --> I[Sieve rejected]

This ensures sieve aperture sizes meet IS 460 Part 3 quality standards.

IS 460 Part 3 – Perforated Plate Test Sieve

Key Specifications (Clause 2.2):

• Material: Mild steel, stainless steel, or brass plates.
• Perforations: Circular holes, accurately punched.
• Hole Diameter: As per nominal sieve size (e.g., 2 mm, 4 mm).
• Plate Thickness: Typically 0.5 mm to 1.0 mm for durability.
• Open Area: Minimum 40% open area for effective sieving.
• Tolerance on Hole Diameter: ±0.02 mm for precision.

Common Formula:

• Open Area (%) = (\frac{\pi}{4} \times d^2 \times n \times 100 / A)

  Where:
  (d) = hole diameter
  (n) = number of holes
  (A) = total plate area

Typical Table: Hole Diameter vs. Sieve Size

Note: IS 460 Part 3 emphasizes precision in hole size and uniformity for reproducible test results.

Inspection Eligibility of Apertures (IS 460 Part 3)

• Measurement Directions:
  Apertures must be measured in warp and weft directions separately for tolerances X, Y, Z (Clause 2.1.4).

• Measurement Tools:
  Use optical projectors, microscopes, or coordinate measuring tables for precise aperture size measurement.

• Oversize Apertures:

  • Apertures deviating by ~10% from average size are visually detectable (Clause 2.1.5).
  • Any aperture exceeding the maximum permissible deviation X is rejected.

• Inspection Eligibility:

  • Every aperture in the perforated plate sieve is eligible for inspection (Clause 2.2.1).
  • Inspection proceeds in stages:
    1. General condition survey
    2. Scrutiny of individual apertures
    3. Measurement for tolerance compliance (Clause 2.2.2)

• Minimum Sample Size:
  If the minimum holes for inspection (per 2.2.5) are unavailable, all apertures must be checked.

Key Tolerance Check Formula

[ \text{Acceptable aperture size} = \text{Average aperture size} \pm X ]

Where:

• X = Maximum permissible deviation (from Part 1)
• Aperture width outside this range = Reject

flowchart TD
    A[Start Inspection] --> B[Survey General Condition]
    B --> C[Scrutinize Individual Apertures]
    C --> D[Measure Aperture Size (X, Y, Z)]
    D --> E{Aperture size within ±X?}
    E -- Yes --> F[Accept Aperture]
    E -- No --> G[Reject Aperture]

This ensures systematic and reliable aperture quality control per IS 460 Part 3.

IS 460 Part 3: Examination Procedure for Test Sieves

Key Points from Clauses 2.1.2 & 2.2.2:

• Examination stages:

  1. General condition survey of the sieve.
  2. Methodical scrutiny of individual apertures.
  3. Measurement of aperture sizes to check compliance with tolerances.

• Number of apertures to measure:

  • If sieve has ≤ 20 apertures, measure all apertures.
  • If more than 20 apertures, measure a minimum number of holes as prescribed (see Clause 2.2.5).
  • If minimum holes not available in one or two directions, check all holes.

Typical Measurement Procedure:

Notes:

• Aperture size tolerance depends on sieve mesh size (refer to IS 460 tables).
• Measurement tools: optical comparator, microscope, or calibrated gauge.

flowchart TD
    A[Start: General Condition Survey] --> B[Scrutiny of Individual Apertures]
    B --> C{Number of Apertures ≤ 20?}
    C -- Yes --> D[Measure All Apertures]
    C -- No --> E[Measure Minimum Number of Holes (Clause 2.2.5)]
    E --> F{Minimum Holes Available?}
    F -- No --> D
    F -- Yes --> G[Measure Selected Holes]
    D & G --> H[Compare Aperture Size with Tolerances]
    H --> I[Pass/Fail Decision]

This procedure ensures compliance with IS 460 Part 3 for test sieve aperture examination.

IS 460 Part 3: General Condition of Perforated Plate (Perforated Plate Test Sieve)

Key Specifications & Inspection Criteria

• Visual Examination (Clause 2.2.3):

  • Inspect against a uniformly illuminated background.
  • Reject if faults like irregular holes, ragged edges, or upward burrs exist.

• Hole Measurement (Clause 2.2.5):

  • Use callipers, tapered plate gauges, plug gauges, or optical projection.
  • For square holes:
    • Check mid-section in both directions (90°).
    • Alternatively, check along a diagonal line (≥150 mm, ≥8 holes).
  • For round holes:
    • Check along two straight lines (≥100 mm, ≥10 holes), lines at 90° or 60°.

• Inspection Coverage (Clause 2.2.1):

  • Every aperture must comply with Part 2 requirements.

Measurement Procedure Summary

flowchart LR
    A[Start Inspection] --> B{Visual Check}
    B -- Faults found --> C[Reject Sieve]
    B -- No Faults --> D[Measure Holes]
    D --> E{Hole Type}
    E -- Square --> F[Check mid-section at 90° or diagonal line]
    E -- Round --> G[Check along two lines at 90° or 60°]
    F & G --> H[Check hole dimensions & tolerances]
    H --> I{Compliant?}
    I -- Yes --> J[Accept Sieve]
    I -- No --> C

Summary: The perforated plate must be free of defects and holes must be measured precisely using specified lines and gauges to ensure compliance with IS 460 Part 3.

IS 460 Part 3: Calibration Tests for Woven Wire Cloth Test Sieves

Key Points from Clause 3.1 & Table 1

• Calibration tests involve measuring aperture widths in multiple fields spread over the sieve surface.
• Fields are selected so no two fields share the same wire.
• Use masks (Fig. 2) for field selection:
  • 10-field mask for most apertures
  • 15-field mask for smaller apertures (e.g., 150 µm, 53 µm)
• Aperture measurements are taken in warp and weft directions separately.

Table 1: Number of Apertures to Measure

(Refer Table 1 in IS 460 Part 3 for full details)

Procedure Summary

• Measure aperture widths in each field.
• Calculate average aperture size.
• Compare with nominal aperture to verify calibration.
• Use masks to ensure uniform sampling.

Visual: Mask Types for Field Selection

graph LR
A[10-Field Mask] -->|Used for| B[Nominal Aperture > 150 µm]
C[15-Field Mask] -->|Used for| D[Nominal Aperture ≤ 150 µm]

Note: Calibration tests ensure precision for master sieves or detailed sieve characterization beyond acceptance tests.