In [Part 1 of our Conveyor Basics Series], we covered the essential components of a conveyor system-pulleys, idlers, and the basic structure of a fabric belt.
But when it comes time to order a replacement belt, you are faced with a confusing string of numbers: "1200 EP 800/4 5+2 M24".
What does this code mean? How do you know if you need an EP belt or a Steel Cord belt? In this guide, we will decode these specifications so you can speak the same language as your supplier.
1. How to Read Fabric Belt Specifications
Fabric belts are the workhorses of the industry, used for short to medium distances. The specification code tells you the belt's strength, carcass material, and cover thickness.
The Formula:
[Width] [Carcass Type] [Strength/Plies] [Top+Bottom Cover] [Grade]
Example Breakdown: 1200 EP 1000/4 10+4 M24
| Code | Component | Meaning |
| 1200 | Width | The belt is 1200mm wide. |
| EP | Material | Polyester/Nylon Carcass. (See comparison below). |
| 1000/4 | Strength | 1000 N/mm total tensile strength, divided into 4 plies (layers). |
| 10+4 | Covers | Top rubber is 10mm (carrying side), Bottom rubber is 4mm (pulley side). |
| M24 | Grade | Abrasion Resistant rubber grade (Standard ISO grade). |
2. Choosing the Carcass: NN vs. EP vs. Cotton
The letters EP or NN refer to the material of the fabric plies inside the belt. This is the most critical choice you will make.
A. Cotton Canvas (CC) - The Obsolete Choice
- Pros: Cheap, lightweight.
- Cons: High elongation (stretch), rots easily when wet, low strength.
- Verdict: Rarely used in modern heavy industry.
B. Nylon/Nylon (NN) - The Flexible Choice
- Structure: Nylon warp (lengthwise) + Nylon weft (crosswise).
- Pros: Extremely flexible, excellent troughability, high impact resistance.
- Cons: High Elongation (1% - 2.5%). If you have a 100m conveyor, the belt might stretch 2.5m! You need a long take-up system to compensate.
- Verdict: Good for short lines with high impact loads.
C. Polyester/Nylon (EP) - The Industry Standard
- Structure: Polyester warp + Nylon weft.
- Pros: Low Elongation (<1.5%), high dimensional stability, moisture resistant.
- Verdict: The best all-rounder for mining, quarries, and cement plants.
3. Steel Cord Belts: The Heavy Lifters
For long-distance transport (kilometers long) or extremely high tension, fabric belts stretch too much. This is where Steel Cord (ST) belts come in. Instead of fabric plies, these belts use galvanized steel cables embedded in the rubber.
Steel Cord Specification: ST 2000 1200 8+6
| Code | Meaning | Details |
| ST | Type | Steel Cord Belt. |
| 2000 | Strength | 2000 N/mm tensile strength. |
| 1200 | Width | 1200mm wide. |
| 8+6 | Covers | 8mm Top Cover, 6mm Bottom Cover. |
Advanced Specs (Internal Structure)
Sometimes you need to know more details about the cables inside:
- Cord Diameter: e.g., Ø5.0mm.
- Pitch: The distance between the center of one cord to the next (e.g., 12mm).
- Metal Breaker: An optional transverse mesh layer added above the cords to prevent "longitudinal ripping" if a sharp rock pierces the belt.
4. Rubber Cover Grades (The Protection)
The final part of the spec is the "Grade" (e.g., M24, DIN-Y, HR). This defines what the rubber skin can withstand.
- General Purpose (DIN-Y / M24): For coal, crushed stone, sand. Good abrasion resistance.
- Super Abrasion Resistant (DIN-W): For very sharp, hard materials like granite, copper ore, or glass cullet.
- Heat Resistant (HR):
- T1: Materials up to 100°C.
- T2: Materials up to 125°C.
- T3: Materials up to 150°C+ (Cement Clinker, Sinter).
- Oil Resistant (OR): For oily grains (soybeans) or fertilizers.
- Fire Resistant (FR): Mandatory for underground coal mining or power plants.
Conclusion
Reading a conveyor belt specification is easy once you know the code.
Need flexibility? Choose NN.
Need stability? Choose EP.
Need long distance? Choose Steel Cord (ST).
In the final part of this series, [Part 3: Safety Devices], we will look at the essential switches that keep these belts running safely.
Ready to order?
Henan Kunwei Machinery manufactures belt conveyor system to your exact specifications.
