What is Conveyor belts
What Is a Conveyor Belt? Construction, Manufacturing, Specifications and Applications
A Conveyor Belt is a continuous reinforced belt used to transport bulk materials, components, or finished products from one point to another. It forms the carrying surface of a belt conveyor and moves continuously around pulleys while being supported by idlers.
An industrial Conveyor Belt is a multi-layer engineered component rather than simply a rubber sheet. Its construction normally includes a reinforcement carcass, skim rubber, top cover and bottom cover. The selection of reinforcement, tensile strength, cover compound and belt dimensions depends on the conveyed material, conveyor length, belt speed, loading conditions, temperature, abrasion and impact.
How Does a Conveyor Belt Work?
A typical belt conveyor consists of a Conveyor Belt, drive pulley, tail pulley, carrying idlers, return idlers, take-up arrangement and supporting structure.
The drive pulley transmits torque to the belt through friction. As the pulley rotates, the continuous belt loop moves along the carrying side and returns underneath the conveyor.
Carrying idlers support the loaded belt, while return idlers support the empty belt. The belt therefore operates as part of a complete mechanical system.
Factors such as belt tension, pulley diameter, conveyor capacity, belt speed, loading method and conveyor inclination must be considered when selecting a belt.
What Is a Conveyor Belt Made Of?
A Rubber Conveyor Belt consists of several functional layers, with each layer performing a different mechanical role.
Carcass or Reinforcement
The carcass is the internal structural component that provides longitudinal tensile strength and supports the conveyed load.
Depending on the belt construction, reinforcement can use nylon, polyester or steel. The reinforcement influences tensile strength, elongation, flexibility, impact resistance and dimensional stability.
Textile reinforcement is commonly selected where flexibility and suitable tensile performance are required, while steel reinforcement can be used for applications requiring very high tensile strength.
Rubber Skim
Skim rubber is positioned around the reinforcement layers. It bonds the reinforcement components together and helps transfer mechanical stresses between the carcass and rubber.
The adhesion between rubber and reinforcement is important because loss of adhesion can result in layer separation and premature belt failure.
Top Cover
The top cover is the working surface that contacts the conveyed material.
Its compound and thickness depend on the operating environment. Abrasive materials require suitable wear resistance, while high-temperature applications require a compound designed for the specified thermal conditions.
Depending on the application, cover compounds can be selected for abrasion, heat, oil, fire, cut, tear and impact resistance.
Bottom Cover
The bottom cover protects the carcass from contact with idlers, pulleys and conveyor components.
The top and bottom covers can have different construction requirements because the two surfaces experience different operating conditions.
Conveyor Belt Technical Specifications
Conveyor Belt performance is determined by a combination of dimensions, reinforcement, tensile rating and rubber properties.
| Technical Parameter | Specification | Engineering Significance |
|---|---|---|
| Belt Width | 300–2,000 mm | Determines the available carrying width and influences the material-handling capacity of the conveyor. |
| Belt Thickness | 4–20 mm | Overall thickness depends on carcass and cover construction and provides structural support and wear protection. |
| Tensile Strength | 30–3,150 N/mm | Indicates the nominal longitudinal tensile rating. Selection depends on conveyor tension, length, loading and operating conditions. |
| Reinforcement | Nylon, Polyester or Steel | Provides tensile strength and influences flexibility, elongation, impact resistance and dimensional stability. |
| Rubber Cover | Abrasion, Heat, Oil, Fire, Cut, Tear and Impact Resistant Options | The cover compound is selected according to the conveyed material and environmental, mechanical and thermal conditions. |
| Temperature Range | -20°C to 200°C* | Temperature capability depends on the belt construction, rubber compound and actual operating conditions. |
| Belt Grades | M24, N17, HR, SHR, OR, FR | Different grades provide properties suited to operating conditions such as abrasion, heat, oil and fire resistance. |
| Surface Construction | Smooth, Chevron, Rough Top | Surface profile is selected according to material handling requirements, grip and conveyor inclination. |
| MRF Conveyor Belt | 300–2,400 mm Width 4–25 mm Thickness 100–3,150 N/mm |
MRF belt construction is designed for material recovery applications and has a separate dimensional and tensile range. |
| Chevron Conveyor Belt | 400–1,800 mm Width 5–25 mm Thickness 5–32 mm Cleat Height |
Chevron profiles increase grip and help reduce material rollback on inclined conveyors. Applications can reach approximately 40° depending on configuration. |
*Temperature capability is product- and application-dependent and should be selected according to the specific belt construction and operating conditions.
How Are Conveyor Belts Manufactured?
The manufacturing process combines rubber compounds and reinforcement materials into a controlled multi-layer structure.
1. Rubber Compound Preparation
Rubber polymers and selected ingredients are mixed to produce compounds with the required physical properties.
Different compounds can be formulated for operating conditions such as abrasion, elevated temperature, oil exposure or flame resistance.
2. Calendering
During calendering, rubber is applied to the reinforcement fabric under controlled conditions.
This produces rubber-coated reinforcement layers with controlled thickness and suitable adhesion. Consistent rubber distribution and fabric alignment are important for uniform belt construction.
3. Belt Building
The prepared components are assembled in the required sequence.
A typical textile-reinforced construction can be represented as:
Top Cover → Skim Rubber → Reinforcement → Skim Rubber → Bottom Cover
The reinforcement construction, belt rating and cover configuration depend on the intended operating duty.
4. Vulcanization
The assembled belt is subjected to controlled heat and pressure during vulcanization.
The process cures the rubber compounds and develops the required physical properties and bonding between the different layers.
Control of curing conditions is important because insufficient or excessive curing can affect the final rubber properties and layer adhesion.
5. Inspection and Testing
Finished Conveyor Belts can be checked for dimensional, construction and physical requirements.
Depending on the belt type, checks can include:
- Belt width and thickness
- Cover thickness
- Tensile strength
- Elongation
- Rubber hardness
- Abrasion resistance
- Adhesion between rubber and reinforcement
- Surface and edge condition
Types of Conveyor Belts
Different materials and operating conditions require different belt constructions.
General Duty Conveyor Belt
General Duty Conveyor Belt is Used for conventional bulk-material conveying where extreme temperature, oil exposure or severe abrasion is not the dominant operating condition.
Oil Resistant Conveyor Belt
Oil Resistant Conveyor Belt is Used where oils or fats in the conveyed material could adversely affect conventional rubber compounds.
Fire Resistant Conveyor Belt
Fire Resistant Conveyor Belt is Used in applications where resistance to flame propagation is an important operating requirement.
Chevron Conveyor Belt
Chevron profiles are moulded onto the carrying surface to increase grip and reduce material rollback when conveying material on inclined conveyors.
How to Select the Right Conveyor Belt?
A Conveyor Belt should be selected from the complete conveyor operating duty rather than from belt width or price alone.
Important parameters include:
- Material being conveyed
- Required conveying capacity
- Belt width
- Belt speed
- Conveyor length
- Operating tension
- Material temperature
- Material lump size
- Abrasion level
- Impact at the loading point
- Oil or chemical exposure
- Conveyor inclination
- Pulley diameter
- Take-up arrangement
- Splicing method
Structure and Functionality
A conveyor belt system typically consists of two or more pulleys (sometimes called drums) with a loop of material—the conveyor belt—that rotates around them. One or more of the pulleys are powered, moving the belt and the material on it forward. The powered pulley is called the drive pulley, while the unpowered one is the idler pulley.
The belt itself can be made from various materials, depending on the application. Common materials include rubber, PVC, polyurethane, and metal. Rubber belts are widely used due to their flexibility, strength, and durability. They are ideal for transporting bulk materials such as coal, ore, and grains. PVC and polyurethane belts are often used in food processing and packaging due to their resistance to oils, chemicals, and moisture, as well as their ability to meet food safety standards. Metal belts are used in high-temperature environments or for handling heavy items that might damage other types of belts.
Applications
Conveyor belts are ubiquitous in industries that require the transportation of materials or products over short or long distances. In manufacturing, they are used on assembly lines to move products from one station to another, ensuring a smooth production process. In mining, conveyor belts transport raw materials from extraction sites to processing plants, reducing the need for manual labor and improving safety.
In the food and beverage industry, conveyor belts are used to transport ingredients and finished products through various stages of production and packaging. In airports, conveyor belts carry luggage from check-in counters to sorting areas and eventually to the aircraft. Warehouses and distribution centers use conveyor belts to move packages from storage areas to loading docks, facilitating the shipping process.
Frequently Asked Questions
What is a Conveyor Belt?
A Conveyor Belt is a continuous reinforced belt used to transport materials or products through a conveyor system. A rubber belt generally consists of reinforcement, skim rubber and protective covers.
What is the tensile strength of a Conveyor Belt?
Tensile strength is commonly expressed in N/mm and represents the nominal longitudinal strength of the belt construction. CHERRY’s published Rubber Conveyor Belt range covers 30–3,150 N/mm, depending on construction.
What sizes of Conveyor Belts does CHERRY supply?
CHERRY publishes Rubber Conveyor Belts in widths from 300 to 2,000 mm and thicknesses from 4 to 20 mm. Other specialized belt categories have different specifications.
How are Conveyor Belts manufactured?
The general process includes rubber compound preparation, calendering, belt building, vulcanization and final inspection or testing.
How should a Conveyor Belt be selected?
Selection should consider belt width, tensile strength, material characteristics, capacity, belt speed, conveyor length, temperature, abrasion, impact, pulley diameter, inclination and operating tension.
Conclusion
CHERRY supplies Conveyor Belts for industrial material-handling applications, with belt construction selected according to the required width, tensile strength, reinforcement, cover properties and operating environment.
The published CHERRY Rubber Conveyor Belt range includes 300–2,000 mm widths, 4–20 mm thicknesses and tensile strengths from 30–3,150 N/mm. CHERRY also lists specialized belt grades including M24, N17, HR, SHR, OR and FR.
For a specific requirement, providing the belt width, belt length, conveyed material, capacity, belt speed, material temperature, conveyor inclination and existing belt construction helps determine a suitable belt specification.