how to calculate tph of conveyor
Calculating TPH of a Conveyor in Aggregate Processing
In the aggregate and sand production industry, conveyor belts play a critical role in transporting raw materials, crushed stone, and finished products. Accurately calculating the throughput (TPH – tons per hour) of a conveyor ensures efficient plant design and operation. Here’s a step-by-step guide tailored for professionals in crushing and screening applications.
Key Factors for TPH Calculation
1. Belt Speed (V) – Measured in meters per second (m/s) or feet per minute (fpm), this is the velocity at which the belt moves.
2. Material Density (ρ) – The bulk density of the conveyed material (e.g., limestone ~1.5 t/m³, granite ~1.6 t/m³).
3. Cross-Sectional Load Area (A) – Determined by belt width, troughing angle, and material surcharge angle.
Basic Formula
The standard formula for calculating TPH is:
\[
TPH = V \times A \times ρ \times 3600 \, (\text{for m/s}) \quad \text{or} \quad V \times A \times ρ \times 60 \, (\text{for fpm})
\]
Step-by-Step Breakdown:
- Measure Belt Speed: Use a tachometer or encoder to confirm actual belt speed vs. design specifications.
- Determine Load Area: For troughed belts, apply the cross-sectional area formula based on idler geometry (e.g., 35° trough = ~30% surcharge).
- Apply Material Density: Verify density through lab testing or industry standards—adjust for moisture content if necessary.
- Material Flowability: Sticky or wet materials may reduce effective capacity due to adhesion or carryback.
- Incline/Decline Effects: Steep inclines (>15°) require power adjustments and may reduce throughput by up to 20%.
Practical Considerations
FAQ
Q: How does belt width impact TPH?
A: Wider belts allow higher load areas but require proper idler spacing to prevent spillage—common widths range from 24″ to 72″ in aggregate plants.
Q: What if my actual TPH is lower than calculated?
A: Check for slippage, improper tensioning, or material buildup on pulleys/idlers affecting speed consistency.
Case Example
A granite quarry upgraded from a 36″ to 48″ belt while maintaining 450 TPH output by optimizing speed (+15%) and troughing angle (45° → 60°), reducing spillage losses by 12%.
For precise results, always validate calculations with real-world operational data and adjust for site-specific conditions like altitude or temperature variations affecting belt performance.