Dimensions and materials of cement rotary kilns, components and auxiliaries (dry process with suspension preheater)

IS 8125 - Scope: Key Specifications & Tables

1. Kiln Size (Clause 2.1, Table 1):
   • Kiln size = Inside shell diameter & nominal length.
   • Sizes A to F with inside diameter from 2.9 m to 5.0 m.
   • Length ranges from 44 m to 85 m.
   • Number of supports: 3 or 4 depending on size.

2. Kiln Tyres (Clause 5.1, Table 3):

   • 12 sizes, outside diameter from 3,550 mm to 6,160 mm.
   • Preferably hollow cross-section to reduce weight.
   • Width ranges from 600 mm to 1,600 mm.

3. Girth Gears & Pinions (Clause 5.3, Table 5):

   • 6 sizes with outside diameter from 4,610 mm to 7,476 mm.
   • Face width girth gear: 450 mm to 750 mm.
   • Pinion face width: 500 mm to 800 mm (twin drive up to 2×650 mm).
   • Module ranges from 24 to 42.

4. Drive Motors & Gear Boxes (Clause 5.4, Table 6):

   • 7 sizes, power from 50 kW to 275 kW.
   • Motor speed up to 1,000 rpm.
   • Gearbox power matches motor power.

Summary Diagram of Kiln Size Parameters

IS 8125: Kiln Size and Designation - Key Specifications

1. Kiln Size (Clause 2.1, Table 1)

• Representation: Inside shell diameter (m) × Nominal length (m)
• Typical sizes:

2. Kiln Tyres Dimensions (Clause 5.1, Table 3)

• Tyres are preferably hollow cross-section to reduce weight.
• Sizes vary; example:

3. Kiln Shell Thickness (Clause 3.1, Table 2)

| Kiln Zone | Thickness (mm) |

Thickness of Kiln Shell (IS 8125: Clause 3.1 & Table 2)

• Thickness selection depends on kiln diameter and load zones.
• Thicker plates are used under tyres and girth gear due to higher stresses.

Material Specifications for Kiln Shell (Clause 6.1 & Table 7)

• Non-destructive testing is mandatory to avoid defects.
• Refractory bricks quality varies by kiln zone (IS 6, 8, 1749, 2042).

Summary Diagram

flowchart TD
    A[Kiln Zones] --> B[Calcining, Burning, Cooling]
    A --> C[Under Tyres]
    A --> D[Under Girth Gear]
    B --> E[Thickness: 18-40 mm]
    C --> F[Thickness: 45-90 mm]
    D --> G[Thickness: 28-63 mm]
    H[Steel Plate Material] --> I[IS 226 (≤20 mm)]
    H --> J[IS 2062 (>20 to ≤50 mm)]
    H --> K[IS 2002 (>50 mm)]

Key Points:

• Use Table 2 thickness as per kiln zone.
• Choose steel grade per thickness as per Table 7.
• Ensure NDT for steel plates.
• Select refractory bricks per zone for thermal protection.

This ensures structural integrity and durability of kiln shells per IS 8125.

Thickness of Refractory Lining (IS 8125)

• Minimum refractory lining thickness:
  150 mm (Clause 4.1)

• Zones requiring higher thickness:

  • Calcining, burning, and cooling zones (Clause 3.2)
  • Sections adjacent to tyres (Clause 3.2)

Thickness of Steel Shell Plates (Table 2, Clause 3.1)

Material Specifications (Table 7, Clause 6.1)

Notes:

• Use higher refractory thickness near tyres and high-temperature zones.
• Non-destructive testing of steel plates is mandatory to avoid defects.
• High alumina refractories can be used in burning zones as per purchaser-manufacturer agreement.

flowchart TD
    A[Kiln Zones] --> B[Calcining, Burning, Cooling]
    B --> C[Refractory

IS 8125 Key Specifications for Cement Rotary Kiln Dimensions and Auxiliaries

1. Kiln Dimensions (Clause 2.1, Table 1)

• Inside Diameter (m) & Nominal Length (m):

2. Kiln Tyres Dimensions (Clause 5.1, Table 3)

• Preferred sizes (mm):

• Note: Hollow cross-section preferred to reduce weight.

3. Girth Gears and Pinions (Clause 5.3, Table 5)

| Dimension | G1 | G2 | G3 | G4 | G5 | G6

IS 8125: Materials of Construction for Kiln Shell & Refractory

1. Kiln Shell Material (Clause 6.1, Table 7)

2. Refractory Brick Quality (Clause 6.1, Table 7)

3. Components & Auxiliaries Material (Clause 6.2, Table 8)

4. Shell Thickness (Clause 3.1, Table 2)

IS 8125: Materials & Dimensions for Components and Auxiliaries

1. Materials for Components (Table 8)

Higher grades may be used if required.

2. Dimensions of Kiln Tyres (Table 3)

Tyres preferably hollow cross-section to reduce weight.

3. Dimensions of Girth Gears & Pinions (Table 5)

Summary Diagram

graph TD
A[Components & Auxiliaries] --> B[Tyres]
A --> C[Support Rollers]
A --> D[Girth Gear]
A

IS 8125 - Drive Motors and Gear Boxes (Clause 5.4)

The standard specifies 7 sizes of kiln drive motors and gear boxes as per Table 6:

Key Points:

• Motors are continuously variable speed up to 1000 rpm.
• Gearboxes are matched to transmit the same power as the motor rating.
• Selection depends on kiln size and power requirements.

Related Components Dimensions (for coordination):

Typical Formula for Power Transmission:

[ P = \frac{2 \pi N T}{60} ]

Where:

• (P) = Power (W)
• (N) = Speed (rpm)
• (T) = Torque (Nm)

This helps in sizing gearboxes and motors based on torque and speed.

flowchart LR
    Motor[Drive Motor<br>(50-275 kW)] --> Gearbox[Gear Box<br>(Same power rating)]
    Gearbox --> GirthGear[Girth Gear & Pinion]
    GirthGear --> Kiln[Rotating Kiln]

**Summary

Non-Destructive Testing (NDT) Requirements as per IS 8125

Clause Reference: 6.1 & Note 1 (Table 7)

Key Points:

• NDT is mandatory for kiln shell steel components to detect laminations and other defects.
• Applies irrespective of steel type or thickness.
• Ensures reliability and structural integrity of kiln shell parts.

Relevant Steel Specifications for Kiln Shell:

Common NDT Methods for Steel Plates:

• Ultrasonic Testing (UT): Detects internal laminations, inclusions, and cracks.
• Radiographic Testing (RT): Visualizes internal flaws using X-rays or gamma rays.
• Magnetic Particle Testing (MPT): Surface and near-surface crack detection in ferromagnetic materials.
• Dye Penetrant Testing (DPT): Surface crack detection on non-porous materials.

Summary Table for NDT Application on Kiln Shell Steel

Additional Notes:

• For refractory bricks, quality standards are specified but NDT is not applicable.
• High alumina refractories may be used in high-temperature zones as per purchaser-manufacturer agreement.

flowchart TD
    A[Kiln Shell Steel Components] --> B{Thickness}
    B -->|≤ 20 mm| C[IS 226-1975]
    B -->|20-50 mm| D[IS 2062-1969]
    B -->|> 50 mm| E[IS 2002-1962]
    C --> F[NDT: UT, MPT, DPT]
    D --> G[N

IS 8125: Standardization Principles & Benefits (Summary)

Key Points:

• Standardization Basis: Kilns standardized by inside shell diameter and nominal length rather than daily clinker capacity, to reduce variety and optimize design.
• Benefits:
  • Simplifies design & manufacturing
  • Reduces delivery time
  • Enables advance ordering
  • Facilitates interchangeability
  • Optimizes operational parameters
  • Lowers overall cost of cement plant machinery

Important Tables & Specifications:

Table 1: Kiln Dimensions

Table 3: Kiln Tyre Dimensions (Selected)