Analysis of main structure composition and abnormal problems of belt conveyor

The conveyor belt of the strong belt conveyor is composed of multiple steel ropes instead of the canvas layer (or other materials) of the common conveyor belt as the core body, so the conveyor belt has high tensile strength.
Difference: Compared with the general belt conveyor, the main feature of the strong belt conveyor is the different structure of the conveyor belt. The conveyor belt of the strong belt conveyor is composed of multiple steel ropes instead of the canvas layer (or other materials) of the common conveyor belt as the core body, so the conveyor belt has high tensile strength. This kind of conveyer can realize single long-distance transport without reprinting, simplify the transport system, improve the transport efficiency.
Technical characteristics: The main technical characteristic parameters of strong belt conveyor are product specifications, conveyor capacity (t/h), conveyor length (m), conveying material type, conveyor belt width (mm), belt strength (N/mm), belt speed (m/s), conveyor belt steel rope core diameter (mm), number of roots, motor model, rated power (kW), rated voltage, reducer specification type Number, brake specifications, brake torque, etc.
Working principle: When the powerful belt conveyor works, the motor rotates through the reducer and coupling to convert the electric energy into the working torque of the driving drum. The movement between the driving drum and the conveyor belt depends on the friction force to drive the conveyor belt. The cargo moves with the conveyor belt on the conveyor belt. The strong belt conveyor generally uses the upper belt to transport the cargo, and it is unloaded at the end. The special unloading device can also be unloaded in the middle.
Specification type: The strong belt conveyor in our coal system use a lot, especially in recent ten years develop very fast. At present, although the strong belt conveyor is not shaped products, but the product series has been standardized.
At present, the strong belt conveyor produced in our country has 7 kinds of bandwidths, 5 kinds of belt speeds and 10 kinds of belt strength, which can form 51 kinds of different specifications of products to choose.
The bearing section and return section of the conveyor belt are supported on the frame idlers to reduce the running resistance of the conveyor belt. And the tension device provides the required tension force for the normal operation of the conveyor belt.
Compared with the general belt conveyor, the strong belt conveyor has the following characteristics:
(1) The conveyor belt of the general belt conveyor uses canvas, polyester, nylon and other fibers as the core layer of the conveyor belt; The conveyor belt of the strong belt conveyor is made of many fine steel ropes as the core layer material.
(2) Due to the limitation of the strength of the conveyor belt, the current maximum length of the general belt conveyor is generally l000 m; The conveyor belt of the strong belt conveyor adopts the silk rope as the core layer, greatly improving the strength of the conveyor belt, and the transport distance can reach 15,000 m.
(3) the general belt conveyor has shaped products, users only need to choose according to the conditions of use; Strong belt conveyor has not been finalized design products, the user needs to put forward conditions, to choose standardized design products.

The high dip Angle wavy guard conveyor belt is composed of three parts: base belt, guard edge and diaphragm. The retaining edge is used to prevent the material from slipping and scattering. In order to facilitate the bypass of the drum, the stop edge is designed to be corrugated; The role of the diaphragm is to support the material, in order to achieve large dip Angle transportation, the use of T type TC type. The baffle and the baffle are connected to the baseband by secondary vulcanization method, which has a high connection strength.
Product features:
1, increase the transmission Angle (30~90 degrees);
2, small area, less investment;
3, large throughput, higher lifting height;
4. Transition from horizontal to inclined (or vertical);
5. It is suitable for conveying powdery, granular, small block, pasty and liquid materials that are easy to scatter;
6, low energy consumption, simple structure, high belt strength, long service life.
Wavy guard conveyor belt (ordinary large dip Angle wavy guard conveyor belt) varieties:
According to the different properties of the covering adhesive, the wavy retaining conveyor belt is divided into ordinary type, heat resistant type, flame resistant type, cold resistant type, acid and alkali resistant type, oil resistant type, etc.

The drum of a belt conveyor comes in two forms. One form for the electric drum, it is the motor and gear reduction device all designed in the drum, although compact structure, light volume, but not easy to install, disassembly, is not conducive to maintenance and repair, and the manufacturing process is complex, heat dissipation is difficult. Another form for the gear drum, it is the gear reduction device design in the drum, absorb the advantages of the electric drum compact structure, light volume, but it and the electric drum as the heat dissipation condition is poor, so can only be used in the low power belt conveyor. In this paper, we take the low power roller of 15kW as an example to illustrate the gear roller used for belt conveyor.
The main advantages of the gear driven drum are: reliable work, long service life, its instantaneous transmission ratio is constant, smooth work, high transmission efficiency. There are many kinds of gear drive drum, such as cylindrical gear drive, bevel gear drive, planetary gear drive, etc. As the transmission ratio of the reducer designed this time is only 12.828, and its working conditions are better, with the general ordinary gear transmission can meet the requirements. For economic consideration, we decided to use two - stage cylindrical gear drive drum.
1. Design of gear drum transmission scheme
(1) Original data
The service life of the gear drum is 10 years, 300 working days per year, 1 shift per day, 7h per shift. One year for minor repairs, three years for major repairs. The ambient temperature does not exceed 400 ° C. Its technological parameters are as follows:
Gear drum diameter (mm) : 500;
Conveyor belt width (mm) : 800;
Width of gear drum (mm) : 950;
Installation size (mm) : 1 300;
Conveyor belt running speed (m/s) : 210;
Motor power (kW) : 15;
Motor speed (r/min) : 980.
(2) Transmission scheme design
This design uses two level cylindrical gear transmission, motor output power transfer to the Ⅰ shaft, drive the Ⅰ shaft pinion 1 rotation, pinion 1 and big gear 2 meshing, at this time the power transfer to Ⅱ shaft, Ⅱ shaft drive pinion 3 and internal gear 4 meshing, so as to transfer the movement to the drum to achieve the purpose of deceleration. The whole gear drive is placed in a support frame, and a butterfly type support bar is designed to connect the inner gear 4 to the drum.
2. Determine the transmission parameters of the gear drum
Firstly, the transmission ratio of the two pairs of meshing gears should be allocated, and the following principles should be considered when allocating the transmission ratio:
① The transmission ratio of all levels of transmission should be within a reasonable range, not exceeding the maximum allowable value, in line with the transmission principle at all levels;
(2) Attention should be paid to make all levels of transmission size coordination, symmetrical and reasonable structure;
③ Try to make the outer dimension of the transmission device compact or small weight;
(4) Try to make all levels of gear oil immersion depth reasonable;
⑤ To consider the transmission parts will not interfere with the collision.
3, gear drum gear design
Pinion 1 and pinion 3 were treated with 40Cr, and the hardness was HB241 ~ HB286, with an average of HB260. Both big gear 2 and inner gear 4 were tempered with 45 steel, the hardness was HB229 ~ HB286, and the average was HB240. This design uses standard helical gear transmission, and no displacement. Gear design is considered from two aspects:
(1) The gear drum is calculated according to the contact fatigue strength of the tooth surface;
The gear drum is checked according to the bending fatigue strength of the tooth root.
Because there is no serious overload in the transmission, static strength is not checked. The modulus of the gear and the diameter of the dividing circle can be calculated, and the modulus can be rounded to determine the specific diameter of the dividing circle. When this is done, a suitable and safe gear is obtained. This design uses oil lubrication.
4. Design of gear drum shaft
The gear drum shaft is the main part in this design, so the shaft must be designed reasonably. In this design, the main design of two shafts, namely high speed shaft I and intermediate shaft II. After the preliminary design of shaft Ⅰ, we found that the shaft was not fixed firmly in the axial direction, so a sleeve and two round nuts were used to fix it to ensure the axial fixation.
After the preliminary design of the structure of the shaft, the strength of the shaft must be checked. First check the axle diameter, and then use the safety factor method to check the strength of the shaft. In the calculation of the strength of the shaft, according to the specific load and stress of the shaft, the corresponding calculation method is used, and the appropriate selection of the allowable stress. According to the structure diagram of the shaft, the calculation diagram of the shaft is made, and the bending moment diagram, torque diagram and equivalent bending moment diagram of the shaft are made according to the calculation diagram of the shaft, and then the dangerous section is determined as the middle section of the pinion. The strength of the shaft is checked according to the bending and torsion stress, usually only the section bearing the maximum calculated bending moment of the shaft is checked, and then the fatigue strength of the shaft is checked.
The above calculation shows that the design of the shaft is safe and reliable, and meets the requirements of use.
5. Selection of gear drum bearings
Because the bearing receives radial and axial loads, tapered roller bearings are selected. We choose the bearing model 7308, bearing rated dynamic load 48440N, rated static load 43540N, limit speed 5600r/min(oil lubrication), axial dynamic load coefficient 211, axial static load coefficient 112. After the initial determination of bearing type and model, we calculate and check from three aspects: (1) the calculation of life; (2) Calculation of static load; (3) Allowable speed check.
6. Structure design of other parts of gear drum
In this design, also designed a support frame and a butterfly support bar to fix the gear device in the drum.

Belt conveyors are widely used in underground roads, surface transportation systems, open-pit mines and concentrators. Used for horizontal or inclined transport. For upward sloping transport, the maximum allowable slant of different materials is β. If the beta value exceeds the specified value, due to the insufficient friction between materials and the conveyor belt, materials and materials (that is, the inclination Angle is greater than the Angle of friction), materials will slide, roll down, sprinkling, affecting the normal operation of the conveyor belt, reduce the transmission capacity. Productivity. For downward inclined transportation, the maximum allowable inclination Angle is 80% of the values listed in Table 1-1. If you need to use more than 1-1 dip conveyor, you can choose belt conveyor.

Belt conveyor is a kind of friction driven continuous material conveying machinery. It can be used to form a material transfer process between the initial feed point and the final discharge point on a conveyor line. It can not only carry out the transportation of broken materials, but also can carry out the transportation of finished products. In addition to pure material transportation, it can also meet the technical requirements of the production process of various industrial enterprises, forming a rhythmic assembly line. Therefore, belt conveyor has been widely used in modern industrial enterprises.
Belt conveyor performance is excellent: first, reliable operation. Belt conveyors are used in many important production units that require continuous operation, such as coal handling in power plants, bulk material handling in steel and cement plants, loading and unloading of ships in ports, etc. If the machine is shut down in these circumstances, the loss will be huge. When necessary, the belt conveyor can continue to work.

Belt conveyors are flexible and can receive materials from one or more points, depending on the requirements of the process flow. It can also expel material from multiple points or parts. The belt conveyor is sent to the conveyor belt at multiple points at the same time (such as the conveyor under the coal  bunker in the coal preparation plant) or any point along the length direction of the belt conveyor through uniform feeding equipment to the conveyor, become the main trunk.