Wooden Separators for Lead-Acid Storage Batteries

IS 652: Scope and Key Specifications

• Scope (Clause 0.9):
  Covers technical provisions for wooden separators used in lead-acid storage batteries. It excludes contractual provisions.

• Definitions (Clause 2.0):
  Refer IS 707-1958 for definitions not provided in IS 652.

• Dimensions and Tolerances (Clause 5.5):

• Measurement Methods (Clause 1.1):

  • Method I: More accurate, used in disputes.
  • Method II: Control method for manufacturers lacking Method I apparatus.

• Units: Metric system adopted (Clause 0.8).

Summary Diagram of Tolerances

graph TD
    A[Wooden Separator] --> B[Width: +0.75 / -0.00 mm]
    A --> C[Height: +0.00 / -0.75 mm]
    A --> D[Total Thickness: ±0.05 mm]
    A --> E[Web Thickness: ±0.05 mm]

This ensures precise manufacturing and quality control of wooden separators per IS 652.

IS 652: Terminology & Key Specifications Summary

1. Terminology (Clause 2.0)

• Definitions follow IS 707-1958 for terms not explicitly defined in IS 652.
• Metric system is used throughout (Clause 0.8).

2. Timber Species for Separators (Clause 3.1, Table I)

*Imported timbers are marked with an asterisk.

3. Dimensional Tolerances (Clause 5.5, Table 5)

This summary covers key terminology, accepted timber species, and dimensional tolerances essential for wooden separators in lead-acid batteries as per IS 652.

IS 652: Key Material Specifications for Separators

1. Timber Species (Clause 3.1, Table I)

Separators shall be made from the following timber species:

Note: Timber marked with * is imported.

2. Dimensional Tolerances (Clause 5.5)

3. Electrical Resistance (Clause 6.1)

Summary Diagram of Material Selection

flowchart TD
    A[Select Timber Species] --> B{Is Timber Imported?}
    B -- Yes --> C[Use POC or DFR]
    B -- No --> D[Use FIR, DEO, CYP, CHM, SPR]
    E[Check Dimensions] --> F[Width +0.75/-0.00 mm]
    E --> G[Height +0.00/-0.75 mm]
    E --> H[Thickness ±0.05 mm]
    I[Verify Electrical Resistance] --> J{Thickness?}
    J -- ≤1.88 mm -->

IS 652: Manufacture and Treatment of Veneer Separators

Key Specifications:

• Veneers: Natural color; slight color variation allowed if free from resin, sapstain, or extraneous matter (Clause 3.2.2).
• Dimensions: Width, height, thickness specified by purchaser; default applies to green condition (moisture > 25%) (Clause 5.1).
• Dry/untreated separators: Dimensions of ribs, end-ribs, webs agreed mutually (Clause 5.1).

Treatment Method (Clause 4.2 & Note):

• Boil separators in 2% caustic soda solution for 3 to 5 hours.
• Use fresh solution for each batch.
• Wash separators in cold water after boiling.

Additional Notes:

• Two testing methods for quality control:
  • Method I: More accurate, used in disputes.
  • Method II: Control method for manufacturers lacking advanced apparatus (Clause 1.1).

Summary Table: Treatment Process

flowchart TD
    A[Veneer Separators] --> B[Boil in 2% Caustic Soda]
    B --> C[3 to 5 hours]
    C --> D[Wash in Cold Water]
    D --> E[Treated Separators Ready]

This ensures durability and quality of separators as per IS 652 standards.

IS 652: Dimensions and Tolerances for Separators

Key Specifications (Clause 5.5, Table 5)

Important Notes:

• Dimensions (width, height, thickness) refer to finished and treated separators in green condition (moisture > 25%) unless otherwise specified (Clause 5.1).
• Dry or untreated separators require dimension agreement between purchaser and vendor.
• Separators must be stored moist in a cool place until use (Clause 4.4).

Summary:

• Width can be slightly larger but not smaller.
• Height can be slightly smaller but not larger.
• Thickness tolerances are symmetrical ±0.05 mm.

This ensures proper fit and function in lead-acid batteries.

flowchart LR
    A[Specify Dimensions] --> B{Condition}
    B -->|Green (moisture >25%)| C[Apply tolerances per Table 5]
    B -->|Dry/Untreated| D[Agreement between purchaser and vendor]
    C --> E[Width: +0.75/-0.00 mm]
    C --> F[Height: +0.00/-0.75 mm]
    C --> G[Thickness: ±0.05 mm]

This diagram shows the decision flow for applying tolerances based on separator condition.

IS 652: Electrical Resistance of Separators

Key Specifications (Clause 6.1, Table 6)

Measurement Method (Appendix A & Clause 2.3)

• Use an AC bridge circuit (Fig. 3) with:
  • 1000 c/s oscillator
  • Coupling transformer
  • Amplifier & indicator with harmonic filtering
• Measure resistance with and without holes in the separator.
• Report resistance difference as ohms/cm² of separator face area.

Additional Notes

• Ensure separator squareness: diagonal difference ≤ 1.5 mm (Clause 5.5.1).
• Resistance measurement accounts for reactive balance using a variable condenser.

flowchart LR
    A[AC Bridge Circuit] --> B[Coupling Transformer]
    B --> C[Oscillator (1000 c/s)]
    C --> D[Amplifier & Indicator]
    D --> E[Resistance Measurement]

This ensures accurate, standardized electrical resistance testing for separator quality control.

IS 652: Manganese Content in Separators

• Maximum Mn content:
  Manganese shall not exceed 1.5 mg per 100 g of oven-dry separator (Clause 7.1).

• Determination method:
  Use the method in Appendix B for manganese content measurement.

• Dispute resolution:
  Values from the method in Appendix A are binding (Clause 6.1.1).

Standard Manganese Sulphate Solution Preparation (Clause B-2.1.4):

• Boil 2 min after adding potassium periodate.
• Dilute 10 ml of this to 100 ml for working standard.
• 1 ml of final solution = 0.001 mg Mn.

Visual Mn Content Check (Clause B-3.2.1):

• If test sample color darker than standard → Excess Mn.
• If same or lighter → Mn content satisfactory.

flowchart LR
    A[Prepare Standard Solution] --> B[Boil with K periodate]
    B --> C[Dilute to 1 L]
    C --> D[Dilute 10 ml to 100 ml]
    D --> E[Use 1 ml = 0.001 mg Mn standard]
    F[Test Sample Color] --> G{Compare with Standard}
    G -->|Darker| H[Excess Manganese]
    G -->|Same or Lighter| I[Satisfactory Manganese]

This ensures manganese content control as per IS 652.

IS 652 - Iron Content in Separators

Key Specifications:

• Iron content in the separator is acceptable if the color intensity from the test sample is not deeper than that from the standard iron solution (Clause 2.1.2).
• The standard iron solution preparation (Clause 1.200 d):
  • Dissolve 1.4044 g ferrous ammonium sulphate in 100 ml water.
  • Add 25 ml sulfuric acid (sp. gr. 1.200).
  • Titrate dropwise with 1% potassium permanganate to slight excess.
  • Dilute to 2 liters.
  • This yields a solution with 0.10 mg Fe/ml.

Testing:

• Use the colorimetric comparison method between sample and standard solution.
• In case of dispute, the method in Appendix A is binding (Clause 6.1.1).

Summary Table:

flowchart LR
  A[Separator Sample] --> B[Colorimetric Test]
  C[Standard Iron Solution] --> B
  B --> D{Compare Color Intensity}
  D -->|Sample ≤ Standard| E[Iron Content Acceptable]
  D -->|Sample > Standard| F[Iron Content Exceeds Limit]

This ensures iron contamination is controlled to maintain separator quality.

IS 652: Visual Inspection Key Points (Clause 9)

• Purpose: Ensure separators meet physical integrity and quality requirements.
• Method: Hold separator by margin and examine against light.
• Flexure Test: Apply slight bending to detect splits or cracks.
• Compliance Check: Confirms requirements per Clauses 3.2, 3.2.1, 3.2.2 (related to material and construction).

Related Specifications

Electrical Resistance Limits (Clause 6.1)

Summary Diagram: Visual Inspection Process

flowchart TD
    A[Hold Separator by Margin] --> B[Examine Against Light]
    B --> C{Any Splits or Cracks?}
    C -- Yes --> D[Reject Separator]
    C -- No --> E[Pass Visual Inspection]

Note: Method I (accurate) and Method II (control) are prescribed for iron content testing; visual inspection is a quick field check for physical defects.

IS 652: Packing and Marking of Separators

Packing (Clause 10.1)

• Batch Size: 100 separators per package.
• Container: Air-tight to prevent drying during transit and storage.

Marking (Clause 10.2)

Each package must be legibly and indelibly marked with:

• Manufacturer's name or trademark.
• Optionally, the ISI Certification Mark (Clause 10.2.1), subject to licensing under the Indian Standards Institution rules.

Inspection (Clause 9.1)

• Hold separator by margin and examine against light.
• Apply slight flexure to detect splits.

Summary Table:

flowchart LR
    A[Separators] --> B{Packing}
    B --> C[Batch of 100]
    B --> D[Air-tight Container]
    A --> E{Marking}
    E --> F[Manufacturer Name/Trademark]
    E --> G[ISI Certification Mark (Optional)]
    A --> H[Inspection]
    H --> I[Check against light]
    H --> J[Flexure test for splits]

IS 652 - Method for Measuring Electrical Resistance of Separators

Key Specifications (Clause 6.1)

Measurement Method (Clause 2.3 & 2.4, Appendix A)

• Use an AC bridge circuit (Fig. 3) with:
  • Coupling transformer
  • 1000 c/s oscillator
  • Amplifier with harmonic filter
• Measure resistance with and without a hole in the separator.
• Report resistance difference as ohms per cm² of separator face area.

Important Notes

• Use a variable condenser in the bridge arm for reactive balance.
• Ensure harmonics are filtered out for accurate readings.
• Separator squareness: diagonal difference ≤ 1.5 mm (Clause 5.5.1).

Simplified AC Bridge Circuit (Fig. 3)

graph LR
A[Oscillator (1000 c/s)] --> B[Coupling Transformer]
B --> C[AC Bridge with Variable Condenser]
C --> D[Amplifier with Harmonic Filter]
D --> E[Indicator]

This setup ensures precise measurement of separator resistance per IS 652.

Determination of Manganese Content (IS 652)

Key Steps (Clause B-3.1 Method I):

1. Select 8 random separators, break into chips, mix, take 10-12 g sample.
2. Oven-dry at 105±2°C for 16 hours, weigh accurately.
3. Ignite in muffle furnace at dull red heat (~1 hour).
4. Cool ash, moisten with water, add:
   • 2-3 ml concentrated H₂SO₄
   • 0.5 ml concentrated orthophosphoric acid
5. Add 10 ml water, heat in boiling water bath until dissolved.
6. Filter if turbid.
7. Transfer to 100 ml beaker, dilute to ~50 ml.
8. Add 0.3 g potassium periodate, boil 2 minutes.
9. Cool, dilute to 50-100 ml depending on color.
10. Compare color in colorimeter with Standard Manganese Sulphate Solution.

Standard Manganese Sulphate Solution (Clause B-2.1.4):

• Dissolve 0.0308 g manganese sulphate monohydrate in 200 ml water.
• Add 20 ml concentrated H₂SO₄ + 5 ml orthophosphoric acid.
• Add 3 g potassium periodate, boil 2 min, cool, dilute to 1 litre.
• Take 10 ml, dilute to 100 ml → 1 ml contains 0.001 mg Mn.
• Store in cool, dark place.

Interpretation (Clause B-3.2.1):

• If sample color is darker than standard → Excess manganese.
• If same or lighter → Satisfactory manganese content.

Summary Table:

IS 652: Determination of Iron Content in Separators

Key Specifications & Formulas:

• Standard Iron Solution (Clause 1.200 d):

  • Dissolve 1.404 g ferrous ammonium sulphate in 100 ml water.
  • Add 25 ml sulfuric acid (sp. gr. 1.200).
  • Titrate dropwise with 1% potassium permanganate to slight excess.
  • Dilute to 2 L.
  • Iron concentration = 0.10 mg Fe/ml solution.

• Permissible Iron Content (Clause 2.1.2):

  • Iron in separator is acceptable if color intensity ≤ blank test with permissible iron from standard solution.

• Dispute Resolution (Clause 6.1.1):

  • Use method in Appendix A for final iron content determination.

Summary Table:

Conceptual Flow:

flowchart LR
    A[Prepare Standard Iron Solution] --> B[Titrate with KMnO4]
    B --> C[Dilute to 2L (0.10 mg Fe/ml)]
    C --> D[Test separator sample color]
    D --> E{Color ≤ Standard?}
    E -- Yes --> F[Iron content acceptable]
    E -- No --> G[Use Appendix A method for dispute]

This ensures iron content control by colorimetric comparison with a calibrated standard.