Conveyor Idler Spacing Calculator

Carrying and return idler spacing from belt width and load.

Belt width

Throughput

t/hr

Belt speed

m/s

Bulk density

kg/m³

Minimum belt tension

Max belt sag

Conveyor length

Tab to move between fields

Carrying idler spacing

2 m

≈ 13 smartphones

Return idler spacing

3 m

≈ 20 smartphones

Impact idler spacing1 m

Impact zone length1.6 m

Carrying idler sets51

Return idler sets35

Impact idler sets3

Total idler sets89

Actual belt sag1.6%

Transition distance0.56 m

Material load55.6 kg/m

How to Use This Calculator

Enter the belt width and maximum material load in pounds per foot.
Set material bulk density and belt sag percentage limit.
Input belt tension and trough angle.
Review the maximum allowable idler spacing for carrying and return strands.
Use idler spacing to lay out the conveyor structure and calculate total idler count.

What each input means

Belt width: Standard belt width in mm.
Throughput: Material flow rate in tonnes per hour.
Belt speed: Belt linear velocity.
Bulk density: Material bulk density.
Minimum belt tension: Minimum operating belt tension (from tension calculation).
Max belt sag: Maximum allowable sag between idlers. 2% typical, 3% max.
Conveyor length: Total conveyor center-to-center length.

Carrying idler spacing: Recommended spacing for load-carrying idler sets.
Return idler spacing: Recommended spacing for return (bottom) idler sets.
Impact idler spacing: Spacing in the loading zone for impact idler rolls.
Impact zone length: Length of zone requiring impact idlers at loading point.
Carrying idler sets: Total number of carrying idler sets needed.
Return idler sets: Total number of return idler sets needed.
Impact idler sets: Number of impact idler sets in the loading zone.
Total idler sets: Sum of all idler sets (carrying + return + impact).
Actual belt sag: Belt sag percentage at the calculated carrying spacing.
Transition distance: Minimum distance for belt transition from flat to trough.
Material load: Linear material mass along the belt.

Identify Input Parameters
4 parameters
Belt width = 800, Throughput = 500, Belt speed = 2.5, Bulk density = 1500 = 7 input(s) provided
Calculate Carrying idler spacing
Carrying idler spacing = max(0.6, min(2.0, carryingSpacing))
2 = 2
Calculate Return idler spacing
Return idler spacing = min(3.0, carryingSpacingClamped * 2.5)
3 = 3
Calculate Impact idler spacing
Impact idler spacing = carryingSpacingClamped * 0.5
1 = 1
Calculate Impact zone length
Impact zone length = beltWidthM * 2
1.6 = 1.6