Detailed Explanation of Bulk Bag Structure Composition
The bulk bag consists of multiple components, each with specific functions. Understanding the structural composition of the bulk bag aids in its correct usage and maintenance.
Main Components of the Bulk Bag
1. Bag Body
The bag body is the main part of the bulk bag, bearing the primary load-bearing and packaging functions.
Material: PP Woven Fabric
Specifications:
| Parameter | Description |
|---|---|
| Fabric Weight | 120-220 g/m² |
| Thickness | 0.12-0.25 mm |
| Color | White, Yellow, Blue, etc. |
Functions:
- Load bearing
- Protect materials
- Provide structural support
2. Lifting Loops
Lifting loops are the lifting components of the bulk bag, used for forklift or crane handling.
Types:
| Type | Features | Application |
|---|---|---|
| 2 Loops | Simple structure | Light load |
| 4 Loops | Good stability | General purpose |
| Sleeve Type | Protects loops | Heavy load |
| Crossed Loops | Special design | Specific requirements |
Specifications:
| Width | Load Capacity |
|---|---|
| 50mm | 500kg |
| 70mm | 1000kg |
| 100mm | 2000kg |
3. Top Filling Spout
The top filling spout is used for loading materials.
Types:
| Type | Diameter | Features |
|---|---|---|
| Open Top | Fully open | Fast loading |
| Standard Spout | 350-500mm | General purpose |
| Small Spout | 200-300mm | Flow control |
| Conical Spout | Variable diameter | Prevent overflow |
Accessories:
- Tie straps: Secure the filling spout
- Cover: Dust and moisture proof
- Flap: Protect the filling spout
4. Bottom Discharge Spout
The bottom discharge spout is used for unloading materials.
Types:
| Type | Description | Application Scenario |
|---|---|---|
| Flat Bottom | No discharge spout | No unloading required |
| Standard Spout | 350-500mm | General unloading |
| Full Open Bottom | Bottom fully open | Fast unloading |
| Flap Style | With discharge flap | Prevent splashing |
Accessories:
- Tie straps: Secure the discharge spout
- Star Bottom: Distribute stress
- Reinforcement Straps: Enhance strength
5. Inner Liner
The inner liner is used for moisture-proofing, dust-proofing, or containing special materials.
Materials:
| Material | Features | Application |
|---|---|---|
| PE Film | Moisture and waterproof | General purpose |
| Aluminum Foil | Good barrier properties | Special materials |
| Conductive Film | Anti-static | Flammable materials |
Types:
- Loose Fit: Independent inner liner
- Adhesive Type: Inner liner bonded to outer bag
- Integrated Type: Inner and outer bag integrated
6. Reinforcement Straps (Steiner Bands)
Reinforcement straps are used to enhance the strength and stability of the bulk bag.
Position:
- Around the bag body
- Bottom edge
- Loop connection points
Functions:
- Distribute stress
- Increase strength
- Maintain shape
7. Sewing Thread
Sewing thread is used to connect various components.
Materials:
| Material | Features |
|---|---|
| PP Thread | Consistent with bag material |
| Nylon Thread | High strength |
| Polyester Thread | Good wear resistance |
Sewing Methods:
- Plain Stitch: General sewing
- Chain Stitch: Elastic sewing
- Double Stitch: Reinforced sewing
Special Structural Designs
Ventilation Structure
- Vent holes
- Breathable fabric
- Suitable for materials requiring ventilation
Conductive Structure
- Conductive threads
- Conductive fabric
- Anti-static design
Baffle Structure
- Internal division
- Multi-compartment design
- Suitable for mixed materials
Structural Strength Analysis
Force Analysis
The main stress-bearing parts of the bulk bag during lifting are:
- Lifting Loops: Bear the entire load
- Loop-Bag Body Connection: Stress concentration
- Bag Body Bottom: Material pressure
Strength Design
| Component | Safety Factor |
|---|---|
| Lifting Loops | ≥6:1 |
| Bag Body | ≥5:1 |
| Sewing Joints | ≥5:1 |
How to Choose Bulk Bag Structure?
Based on Material Characteristics
| Material Type | Recommended Structure |
|---|---|
| Granular | Standard inlet/outlet spouts |
| Powder | Small inlet spout + Inner liner |
| Moisture-sensitive | Inner liner + Coating |
| Flammable/Explosive | Conductive structure |
Based on Usage Method
| Usage Method | Recommended Structure |
|---|---|
| Forklift Handling | 4-loop design |
| Crane Lifting | Reinforced lifting loops |
| Stacking Storage | Square design |
| Automated Filling | Special inlet spout |
Structural Quality Inspection
Appearance Inspection
- Neat stitching
- No skipped or broken stitches
- Accurate dimensions
Strength Inspection
- Lifting loop tension test
- Overall lifting test
- Drop test
Conclusion
The structural design of the bulk bag directly affects its performance and safety. Understanding the functions and characteristics of each component helps in correctly selecting and using the bulk bag.
If you have any questions, please feel free to consult our technical team