Basic (Rubber Conveyor Belt)

1. Top cover: In contact with the material; wear-resistant and impact-resistant; 2. Carcass (strength layer): Bears the tensile force.

Divided into fabric plies (NN nylon, EP polyester) and steel cord (ST).

3. Bottom cover: In contact with the idler rollers and drums.

4. Edge rubber: shield the sides of the belt body against delamination and damage. Lightweight PVC/PU belt: Fabric core + PVC/PU coating, with no thick rubber layer.

Materials

1. Rubber conveyor belt (mainstream in heavy industry).

Cover rubber: Natural rubber (NR) and styrene-butadiene rubber (SBR); can be compounded for heat resistance, acid/alkali resistance, oil resistance, or flame retardancy.

Carcass.

NN nylon fabric: Good elasticity and impact resistance, but relatively high elongation.

EP polyester fabric: Low elongation, for long distances.

ST steel cord: High strength, for ultra-long-distance, heavy-load mining and port applications. PVC (Polyvinyl Chloride) (Lightweight) Lightweight, low cost, and flame retardant.

Temperature range 10–80°C; mostly used for light-duty underground and logistics sorting applications; poor impact resistance, not for large ore lumps.

PU (Polyurethane) Oil-resistant, easy to clean, and food-grade; for food and pharmaceutical applications; not resistant to high temperatures or heavy loads of large material.

Classifications

1. Ordinary fabric rubber belt: Coal, sand and gravel, and cement plants, at medium loads; 2. Steel cord conveyor belt (ST): For long-distance, high-capacity mining and port applications.

3. Heat-resistant conveyor belt: For conveying clinker and high-temperature sinter, resistant to 120–200°C; 4. Acid/alkali-resistant and oil-resistant conveyor belts: For chemical and oily materials.

5. Flame-retardant PVC/PVG: For underground coal mines; fireproof and explosion-proof; 6. Patterned or sidewall belt for steep inclines: The large angle stop material from sliding back.

7. Lightweight PVC/PU belts: For food, packaging, and logistics lines. Scenarios. Mines, sand and gravel plants, power plants, ports: Rubber fabric belts or steel cord belts.

Underground coal mines: Flame-retardant PVG/PVC conveyor belts.

Cement clinker: Heat-resistant rubber belt. Chemical corrosion service: Acid/alkali-resistant rubber belts. Food and packaging sorting: PU and PVC lightweight beltsV.

Problems and Failure Modes

1. Belt misalignment and edge wear: The belt drifts to one side and the edge is scraped and worn by the frame.

Caused by non-parallel idlers or drums, off-center material loading, and uneven tension; long-term misalignment will tear the belt.

Surface wear and rubber loss: Excessive cleaner pressure, seized idlers that will not rotate, and material friction and impact.

The cover rubber thins. Longitudinal tear (serious failure): Metal debris sharp materials stuck in the chute sharp corners of idler roller brackets piercing the belt.

Once a tear occurs, the loss is enormous, and tear protection switches are often installed. Splice damage (weak point).

Vulcanized splice: Rubber separation, blistering, and delamination due to substandard vulcanization temperature and pressure.

Mechanical belt fastener: Loose or broken fasteners; not compatible with alloy cleaning scrapers. Delamination and blistering: Separation of the cover rubber from the carcass.

Caused by water ingress high temperature moisture and aging.

Slippage: Worn drum lagging or insufficient tension makes the belt rub against the drum and generate heat rapidly burning the bottom cover of the belt.

Aging and cracking: Prolonged exposure to sunlight, high temperature, and corrosive media causes the belt to harden and crack.

Key points for operation and maintenance: Regular inspections; cleaner pressure should not be excessive; centre the material feed to reduce misalignment.

Remove iron from sharp materials; splices are a key inspection point.