Conveyor design parameters: the width and speed of a belt conveyor depend primarily on which properties of the handled material?

Introduction / Context:
Conveyor selection and sizing are driven by the material’s physical characteristics. To prevent spillage and excessive wear, designers choose belt width and speed based on lump size and mass flow considerations.

Given Data / Assumptions:

• Handling cold, free-flowing bulk solids.
• Goal: determine which material properties govern width and speed.

Concept / Approach:
Larger lumps require wider belts and larger idler spacings to maintain a cross-section that contains the stream. Higher bulk density increases mass flow for a given volumetric rate, thereby affecting preferred belt speed to keep power and wear within limits.

Step-by-Step Solution:
Relate lump size → minimum belt width to avoid edge spillage.Relate bulk density → mass throughput = volumetric rate * density; speed set by capacity and acceptable belt loading.Thus, both properties matter; select “both (a) & (b).”

Verification / Alternative check:
CEMA and DIN standards use lump size classes and bulk density charts to select width and speed.

Why Other Options Are Wrong:
Either property alone is insufficient for correct sizing.“Neither” is clearly incorrect as design handbooks rely on these inputs.

Common Pitfalls:
Neglecting surcharge angle and moisture, which also influence cross-sectional loading.

Final Answer:
both (a) & (b)