Belt conveyor is an universal continuous transport machinery, with high quality, high efficiency, process adaptability, widely used in ports, power plants, iron and steel enterprises, grain, coal production and light industry and other fields. In recent years, ordinary belt conveyor has shown great potential and broad market application prospect in new industries.
In the process of coal mining, the role of belt conveyor is very important, and its performance directly affects the development and benefit of coal mining industry. Research on belt conveyor is of great significance to coal mine industry and other conveying industries. Generally speaking, the working environment of belt conveyor is relatively bad, and its performance is highly required. This paper mainly introduces the development status of belt conveyor in recent years.
1. Technical status of belt conveyor at home and abroad
As a continuous conveying equipment, ordinary belt conveyor has a wide range of uses in food, coal, metallurgy, tobacco and electric power industries, which can meet the material delivery requirements of flake, block, granular, box and other materials. With the improvement of conveyor belt requirements, domestic and foreign scientific research units and manufacturers have developed several different types of belt conveyor in accordance with the site conditions.
1.1 Plane turning belt conveyor
The research of plane turning belt conveyor is carried out earlier in our country. In 1959, Shanghai Hoisting and Transportation Machinery Factory realized the plane turning operation of ordinary belt conveyor, skillfully used common measures: set up the inner curve raising Angle and installation support Angle in the turning section, these two measures were successfully verified in the prototype. It is a pity that the theoretical research work at that time did not follow up, failed to apply this new process to practical products, which is the embryonic stage of the development of China’s plane turning belt conveyor.
The typical plane turning belt conveyor realizes the correct guidance of turning through the measures of roller forward inclination, increasing roller groove angle, raising inner curve and so on. Compared with other structures, this structure has the advantages of mature theory, simple installation, low investment and maintenance costs. At present, most belt conveyors adopt this structure in the turning section. Its main feature is that the forward inclination design of the idler is adopted on both sides of the bearing section, and the stop rollers are set on both sides of the idler group to prevent the accidental excessive deviation of the belt. The lower idler adopts two wheels or three rods. The upper and lower idlers are of adjustable lifting angle structure, which is convenient to adjust the lifting angle during equipment commissioning, increase the groove angle of the idlers, and appropriately increase the length of the side wheel to increase the guide friction.
1.2 Circular pipe belt conveyor
Circular pipe belt conveyor is usually composed of tail transition section, tubular section and head transition section. The round and simple shape from the tail roller to the belt is called the tail transition section, and the material receiving point is generally within this section. The tape in the tail transition section changes from horizontal to grooved, and finally rolled into a cylindrical shape. In the tubular section, the belt is forced to be wrapped into a cylinder by the idler group, and the transported materials run in the cylinder with the belt.
The tape at the head transition section is gradually expanded from a cylindrical shape to a plane, and then unloaded after reaching the head roller. The return section is the same as the bearing section. Therefore, the conveying steps of circular pipe belt conveyor are: unfolding receiving → closed cylindrical operation → unfolding unloading. The structure of circular tube belt conveyor is similar to that of ordinary belt conveyor, which is composed of driving device, head roller, tail roller, conveyor idler group and frame. The main difference is that the conveyor belt and idler group are different.
The conveyor can transport materials in two directions, but it is usually necessary to add a conveyor belt turnover device. Compared with other closed belt conveyors and general belt conveyors, the circular pipe belt conveyor has a unique structure and has the following advantages:
(1) Environmental protection and no pollution. The circular pipe belt conveyor can transport materials hermetically without flying, scattering and leakage. Since the return branch conveyor belt is tubular, there is no need to worry about the material adhering to the conveyor belt. At the same time, it also prevents the mixing of materials outside the pipe, realizes harmless transportation and avoids environmental pollution.
(2) Large angle tilt capability. Compared with the general belt conveyor, the circular pipe belt conveyor has higher large angle inclined conveying capacity. The conveying section of the conveyor belt is a circular cross section, which increases the contact area between materials and the conveyor belt. The inclination angle of the conveyor increases by 50%, up to 30 °. The larger the inclination angle, the smaller the conveyor length, which is more economical or may become the only feasible solution under the limitation of space and performance.
The upper and lower branches of the circular pipe belt conveyor are wrapped to form a cylindrical shape, so the lower branch can be used to reverse transport materials different from the upper branch (special feeding device needs to be set).
2 Development Trend
With the continuous development of automated production, ordinary belt conveyor has been widely used. Because the conveyor can be horizontal tilt and vertical transmission, but also composed of space transmission lines, transmission lines are generally fixed and large transmission capacity, long distance, but also in the process of transmission at the same time to complete a variety of process operations, so its application is very extensive. In the future, the conveyor will develop to large scale, expand the scope of application, achieve automatic material sorting, reduce energy consumption, reduce pollution. At present, the conveyor in the world has been to the development of long distance, high belt speed, large throughput, high reliability, China has a lot of development space in this aspect.
(1) Continue to develop towards large-scale development. Large scale includes large conveying capacity, large single machine length and large conveying angle. The single length of belt conveyor is close to 20 km, and there has been a number of “belt conveyor” connecting a and B. Many countries are exploring a more perfect conveyor structure for conveying materials continuously over long distances and large throughput.
(2) Expand the scope of use of conveyor. To develop conveyors capable of working in environments with corrosive, radioactive and inflammable substances at high and low temperatures, as well as conveying hot, explosive, agglomerate and viscous materials.
(3) The structure of the conveyor to meet the requirements of the automatic control of the material handling system for single machine. Such as the use of the post office automatic parcel sorting trolley conveyor should be able to meet the requirements of sorting action.
(4) Reduce energy consumption. Reducing energy consumption has become an important aspect of research in the field of transportation technology. The energy consumption of transporting 1 t material ⅰ km is taken as one of the important indexes of conveyor selection.
(5) Reduce the dust, noise and exhaust emissions produced by the conveyor during operation.