Heavy-Duty Conveyor

In mining, ports, steel plants, and large-scale equipment manufacturing workshops, ordinary conveying systems cannot withstand the continuous impact and wear of multi-ton materials or oversized components. The Heavy-Duty Conveyor is specifically designed for these extreme working conditions and is truly the “steel transporter” of industrial production.

These systems are not only required to carry enormous loads but also to withstand high dust levels, high humidity, and continuous 24/7 operation.

Frame Structure and Structural Rigidity

The structural frame of a heavy-duty conveyor must be extremely robust.

The frame is typically fabricated from national standard heavy-duty channel steel or thick-walled square tubing. After welding, the entire structure undergoes stress-relief annealing to eliminate internal stress and prevent deformation during long-term operation. Compared with light-duty conveyors, the spacing between supporting legs is significantly reduced to enhance overall rigidity.

In high-impact zones such as material discharge points, buffer supports or damping springs must be installed beneath the frame to distribute instantaneous impact forces to the ground, preventing anchor bolts from being pulled out.

Drive Drum and Power System

The drive unit is the “heart” of a heavy-duty conveyor.

The drive drum is typically a rubber-coated drum with a rubber layer thickness of up to 20 mm, which increases friction and absorbs impact loads. Instead of a single motor, dual-drive or triple-drive configurations are commonly used, combined with hydraulic couplings or soft-start systems to balance power and ensure smooth startup.

This design prevents excessive inrush current during heavy-load starting, avoids tripping power systems, and protects the conveyor belt from sudden tension-induced failure.

Conveyor Belt Selection and Splicing Technology

The conveyor belt is a wear component, and its selection directly determines maintenance cost.

For sharp materials such as ore and coal, steel cord conveyor belts (ST belts) or multi-ply nylon belts are commonly used. Steel cord belts offer extremely high tensile strength and are suitable for long-distance, high-capacity mainline transportation.

Belt splicing is critical. Cold bonding is no longer suitable; hot vulcanized splicing is required to ensure joint strength reaches more than 90% of the belt’s original strength.

In addition, heavy-duty belt cleaners must be installed at both head and return sections to prevent material buildup and reduce wear on drum coatings.

Idler Sets and Anti-Deviation Design

Idlers are key components supporting both the belt and material load.

Heavy-duty conveyors use deep-trough idler sets, typically with three or five rollers, and trough angles between 35° and 45° to increase load capacity and prevent material spillage.

Idler shafts are thickened, and bearing housings are enlarged with labyrinth seals to prevent dust and water ingress.

For belt tracking control, in addition to self-aligning idler sets, vertical rollers are installed at head and tail sections. If severe deviation occurs and the belt contacts the vertical roller, the system will immediately shut down to prevent edge damage.

Tensioning System and Belt Sag Control

Belt tension control is critical for stable operation.

Heavy-duty systems typically use gravity take-up systems or hydraulic automatic tensioning systems. Gravity tensioning provides constant force through counterweights and is highly reliable for long-distance fixed installations.

Hydraulic tensioning systems respond quickly and automatically adjust tension based on load variations.

Controlling belt sag is essential. Excessive sag increases resistance and causes material spillage, while insufficient sag accelerates wear on belts and drums. Typically, sag on the carrying side is controlled within 2.5%.

Braking and Safety Protection Systems

Safety is a fundamental requirement for heavy-load operation.

For inclined or high-power conveyors, hydraulic brake systems or disc brakes are installed to prevent reverse motion during shutdown or power failure.

Safety systems include:

• Pull-cord emergency switches along both sides of the conveyor

• Belt misalignment switches

• Slip detection sensors

• Belt tear detection systems

Once an abnormal condition is detected, the system must cut power and activate braking within milliseconds to prevent accidents from escalating.

Typical Application Scenario: Port Bulk Material Handling

At port terminals, heavy-duty belt conveyors serve as critical links between stockyards and vessels.

For example, during coal loading operations, conveyors must continuously transport thousands of tons of material within a few hours. In such environments, corrosion resistance is essential due to coastal salt spray exposure. All steel structures are typically hot-dip galvanized or coated with anti-corrosion paint.

To adapt to tidal variations, some conveyor systems are designed as mobile or luffing (tilting) structures. Hydraulic cylinders adjust the height and angle of the discharge boom to ensure precise loading alignment.

Maintenance Focus: Lubrication and Wear Monitoring

Maintenance of heavy-duty conveyors is primarily preventive.

Idlers and drums: Regular inspections are required to detect abnormal noise (bearing damage) and surface cracks.

Conveyor belt: Continuous monitoring of belt wear is necessary, especially at splice joints. Online monitoring systems are often used to detect longitudinal tears and steel cord breakage in real time.

Lubrication system: Centralized lubrication systems must be regularly checked to ensure oil lines are unobstructed and lubricant quality remains stable.