Understanding Belt Strength Ratings and Conveyor Requirements
Each belt is classified by its strength, which denotes the maximum pulling force it can withstand. In the United States, belt strength is measured in Pounds per Inch of Width (PIW), reflecting the tension it can handle. Elsewhere, belts are rated by their ultimate breaking strength in metric units such as newtons per millimeter (N/mm) or kilonewtons per meter (kN/m). This strength rating depends on the belt's carcass reinforcement and the type and number of materials in its fabric plies, or in the case of steel-cable belts, the size of the cables. Notably, the top and bottom covers of the belt contribute minimally to its strength or tension rating.
The belt's strength, whether carcass tension rating or ultimate breaking strength, signifies the force it can endure. Exceeding this capacity with heavier loads, tension from takeup weights, or increased incline could lead to serious issues, potentially causing the belt to break. A higher-rated tension necessitates careful consideration of the belt's compatibility with the conveyor structure and its rolling components.
Each conveyor structure requires a belt with a specific tension rating, determined by factors such as:
- Length of the structure
- Conveyor incline angle
- Desired capacity
- Belt width
- Drag and inertia of rolling components