Q. What is a Belt Conveyor? Explain its main parts.
Ans:
A belt conveyor is a continuous material-handling system that consists of an endless flexible
belt stretched over two pulleys. One pulley drives the belt, while the other maintains tension. Materials
are placed on the moving belt and carried from one point to another. Belt conveyors are widely used
in industries, mining, and agriculture for transporting bulk and unit materials efficiently.
The main parts of a belt conveyor are:
1. Conveyor Belt – The most important component that carries the load.
• Construction: Consists of a carcass (fabric/steel cords for strength) and covers
(rubber/plastic for protection).
• Grades of Covers:
• M24 → Superior abrasion and cut resistance.
• N17 → Good abrasion resistance.
• HR → Heat resistant up to 150°C.
• FRAS → Fire resistant and anti-static.
• PVC → Fire/oil resistant, hygienic.
• Splicing (Joining): Mechanical fasteners (easy, flat belts) or Vulcanizing (strong,
troughed belts).
2. Idlers – Rollers that support the belt.
• Carrying Idlers support the loaded side.
• Return Idlers support the empty belt.
• Troughing Idlers (2, 3, or 5 rollers) give the belt a trough shape for bulk handling.
3. Pulleys – Cylindrical drums over which the belt runs.
• Drive Pulley moves the belt.
• Tail Pulley redirects the belt.
• Snub Pulley increases belt grip on the drive pulley.
4. Belt Tensioning System – Maintains belt tightness to avoid slipping. Types: screw type and
gravity type.
5. Supporting Frame/Structure – Provides rigid support for pulleys, idlers, and belt alignment.
Q. What is an Apron (Pan) Conveyor? Explain its applications.
Ans:
An apron conveyor (also called a pan conveyor) is a type of chain conveyor that consists of one or
more strands of endless chain, usually link-plate roller type, running in steel guides. The chains are
fitted with aprons or pans (metal plates, corrugated plates, or slats) that form a continuous bed to
carry materials.
• Construction and Working:
• The conveyor has rollers to reduce pulling effort and guide rollers supported on the
frame.
• Aprons or pans are attached to the chain links through cleats.
• Material is loaded on the aprons and discharged at the drive end over sprockets.
• The return chain with empty aprons moves back for reuse.
• Operating speed is low (20–35 m/min), suitable for heavy-duty tasks.
• Design Variants of Aprons/Pans:
1. Flat spaced aprons (Slat Conveyor): Flat steel/wooden slats with gaps, used for carrying unit
loads.
2. Corrugated aprons/pans: Overlapping steel pans forming a leak-proof bed, commonly used for
bulk materials.
• Types: Shallow pans, deep pans (for inclined conveying), leakproof pans (for fines), hinged
pans (for scrap).
3. Special designs: For specific uses (e.g., pig casting pans, sugar mill beaded aprons).
Applications of Apron Conveyors:
Apron or pan conveyors are mainly used for heavy-duty material handling in industries.
1. Transporting large bulk materials such as coal, ore, slag, rock, and foundry sand.
2. Feeding heavy-duty machines like crushers, breakers, and grinders.
3. Handling hot materials such as forgings, castings, and furnace scrap.
4. Washing operations – part of the conveyor may pass through liquid or water baths to wash
materials.
5. Used in steel plants, sugar mills, cement plants, and power plants for rugged conveying
tasks.
6. Can follow horizontal and inclined layouts in the same plane for flexibility
