1. Mixing Equipment

• Internal Mixers (Banbury Mixers): These are the workhorses of the rubber mixing process. They consist of a sealed chamber where the raw rubber, along with various additives such as carbon black, sulfur, and accelerators, are vigorously mixed. The rotors inside the mixer have a unique shape that ensures efficient shearing and blending of the materials. Internal mixers are available in different sizes, with capacities ranging from a few kilograms to several hundred kilograms per batch. The larger - capacity mixers are typically used in high - volume production facilities.
• Open - Mill Mixers: These mixers have two horizontally arranged rollers that rotate at different speeds. The raw rubber and additives are fed between the rollers, where the difference in speed creates a shearing action. This shearing action helps to break down the rubber, incorporate the additives uniformly, and develop the desired viscosity and plasticity of the rubber compound. Open - mill mixers are often used for small - scale production, experimental work, or for final adjustments and blending of rubber compounds that have already been pre - mixed in an internal mixer.

2. Calendering Equipment

• Three - Roll Calenders: These calenders consist of three horizontally arranged rollers, with the middle roller typically having a slightly different diameter or surface finish compared to the other two rollers. The rubber compound, which has been pre - mixed and sometimes pre - heated, is fed onto the top roller. As the rollers rotate, the rubber compound is gradually squeezed and spread between the rollers, forming a thin, flat sheet of rubber. The thickness of the rubber sheet can be precisely controlled by adjusting the gap between the rollers. Three - roll calenders are commonly used for producing the base rubber sheets that will later be used in the construction of conveyor belts.
• Four - Roll Calenders: Similar to three - roll calenders, four - roll calenders have four horizontally arranged rollers. The additional roller provides more flexibility in controlling the thickness, surface finish, and quality of the rubber sheet being produced. Four - roll calenders can achieve a higher degree of precision in sheet thickness control compared to three - roll calenders. They are often used for producing high - quality rubber sheets with tight thickness tolerances, which are required for applications such as the manufacture of premium - grade conveyor belts, where consistent quality and performance are crucial.

3. Extrusion Equipment

• Rubber Extruders: These are used to shape the rubber compound into specific forms, such as the edges, profiles, or reinforcing elements of the conveyor belt. A rubber extruder consists of a hopper where the pre - mixed rubber compound is fed, a screw conveyor inside a heated barrel, and a die at the end of the barrel. As the screw rotates, it forces the rubber compound through the heated barrel, where it is gradually softened and plasticized. The softened rubber compound then passes through the die, which gives it the desired shape. Rubber extruders are available in different sizes and configurations, depending on the specific requirements of the conveyor belt production process, such as the size and complexity of the rubber profiles to be extruded.

4. Vulcanization Equipment

• Press Vulcanizers: These are the most commonly used vulcanization equipment in the production of rubber conveyor belts. A press vulcanizer consists of a large, rigid frame that supports a set of heated platens. The conveyor belt, which has been assembled from the various rubber components and reinforcing materials, is placed between the heated platens. The platens are then closed and pressurized, typically to a pressure of several hundred pounds per square inch (psi). At the same time, the platens are heated to a specific temperature, usually in the range of 140 - 180°C (284 - 356°F), depending on the type of rubber compound being used. The combination of heat and pressure causes the rubber molecules to cross - link, a process known as vulcanization. This cross - linking gives the rubber its characteristic elastic properties, strength, and resistance to abrasion, heat, and chemicals. Press vulcanizers are available in different sizes and configurations, with some large - scale production facilities using multi - platen press vulcanizers that can simultaneously vulcanize multiple conveyor belts of different lengths and widths.
• Autoclave Vulcanizers: These are another type of vulcanization equipment that can be used for the production of rubber conveyor belts, especially in cases where large - scale, high - pressure vulcanization is required. An autoclave vulcanizer is a large, cylindrical pressure vessel that is equipped with heating elements, a pressure - regulating system, and a door or hatch for loading and unloading the conveyor belts. The conveyor belts, which have been pre - assembled, are placed inside the autoclave. The autoclave is then sealed, and the pressure inside the vessel is gradually increased, typically to a pressure of several hundred pounds per square inch (psi) or more, depending on the requirements of the vulcanization process. At the same time, the heating elements are activated, and the temperature inside the autoclave is raised to a specific level, usually in the range of 140 - 180°C (284 - 356°F) or higher, depending on the type of rubber compound being used. The combination of high pressure and heat inside the autoclave causes the rubber molecules in the conveyor belts to cross - link, resulting in the vulcanization of the rubber. Autoclave vulcanizers are often used in the production of large - sized, heavy - duty conveyor belts, such as those used in the mining, quarrying, and port industries, where the conveyor belts need to withstand high loads, abrasive materials, and harsh operating conditions.

5. Testing and Inspection Equipment

• Tensile Testing Machines: These machines are used to measure the tensile strength, elongation at break, and modulus of elasticity of the rubber conveyor belt. A tensile testing machine typically consists of a fixed base, a moving cross - head that can be driven up or down by a motorized system, and a load cell that is used to measure the force applied to the sample. The conveyor belt sample is clamped between two jaws, one attached to the fixed base and the other to the moving cross - head. The cross - head is then moved at a constant speed, gradually applying a tensile force to the sample. As the sample is stretched, the load cell measures the force applied to the sample, and an extensometer (or the displacement of the cross - head) is used to measure the elongation of the sample. The tensile strength is calculated as the maximum force applied to the sample divided by the original cross - sectional area of the sample. The elongation at break is the percentage increase in the length of the sample at the point of fracture. The modulus of elasticity is the ratio of the stress (force per unit area) to the strain (change in length per unit original length) in the elastic region of the stress - strain curve. Tensile testing machines are available in different sizes and load capacities, depending on the requirements of the conveyor belt testing process.
• Abrasion Testing Machines: These machines are used to evaluate the abrasion resistance of the rubber conveyor belt. One of the most commonly used abrasion testing machines is the Taber Abraser. The Taber Abraser consists of a turntable that can be rotated at a constant speed, and two abrasive wheels that are pressed against the surface of the conveyor belt sample, which is mounted on the turntable. As the turntable rotates, the abrasive wheels rub against the surface of the sample, causing abrasion. The amount of abrasion is typically measured by weighing the sample before and after a specified number of revolutions of the turntable. The abrasion resistance is then calculated as the weight loss per unit area of the sample. Other types of abrasion testing machines, such as the DIN Abrasion Tester and the Akron Abrasion Tester, use different methods and abrasive materials to evaluate the abrasion resistance of rubber samples. The choice of abrasion testing machine depends on the specific requirements of the conveyor belt application, the type of rubber compound used, and the relevant industry standards and specifications.
• Thickness Gauges: These are used to measure the thickness of the rubber conveyor belt at various points. Thickness gauges can be of different types, including mechanical, ultrasonic, and laser - based thickness gauges. Mechanical thickness gauges typically consist of a caliper - like device with two jaws, one fixed and the other movable. The conveyor belt sample is placed between the jaws, and the thickness is read from a scale on the device. Ultrasonic thickness gauges use ultrasonic waves to measure the thickness of the rubber conveyor belt. The ultrasonic waves are emitted from a probe that is placed on the surface of the conveyor belt sample. The ultrasonic waves travel through the rubber and are reflected back from the opposite surface of the rubber. The time taken for the ultrasonic waves to travel through the rubber and back is measured, and the thickness of the rubber is calculated based on the known speed of sound in the rubber material. Laser - based thickness gauges use a laser beam to measure the thickness of the rubber conveyor belt. The laser beam is projected onto the surface of the conveyor belt sample, and the reflection of the laser beam is detected by a sensor. The distance between the laser source and the sensor is measured, and the thickness of the rubber is calculated based on the known geometry of the laser - based thickness gauge and the position of the conveyor belt sample. The choice of thickness gauge depends on the accuracy requirements of the conveyor belt testing process, the type of rubber conveyor belt being tested, and the relevant industry standards and specifications.
• Visual Inspection Tools: These include magnifying glasses, inspection lamps, and borescopes. Magnifying glasses are used to closely examine the surface of the conveyor belt for any visible defects such as cracks, holes, or unevenness. Inspection lamps provide bright, focused illumination, which helps in clearly identifying any surface irregularities or color variations in the rubber. Borescopes are used to inspect the internal structure of the conveyor belt, especially in cases where there may be hidden defects in the reinforcing layers or between the rubber components. A borescope consists of a flexible tube with a light source and a camera or optical lens at the end. The borescope is inserted into a small opening or through a cut section of the conveyor belt, allowing the operator to view the internal structure of the conveyor belt on a monitor or through an eyepiece. Visual inspection tools are an important part of the conveyor belt quality control process, as they can help in detecting and identifying a wide range of defects at an early stage, before the conveyor belts are put into use.