Conveyor research in the world has been significant development. Along with the application of modern computers, many engineering and technical personnel have developed a new product, with the understanding of physical processes related to transport.
With the global economic growth, the belt conveyor technology has become the forefront of modern science and technological development as one. Today's world need to design and produce "green"-type conveyor, requires delivery of more than 10000t / h, and to conserve energy. Conveyor An important feature of technological progress in basic research and development of applied technology, so as to realize commercialization.
A general belt conveyor is an important research work of
1.1 Technology
1980 - 2000 Conveyor technology have significant development, which to some extent be attributed to research. Application of research findings and recognition often requires business decisions and risk-taking in order to apply these research results to work the system. The main application of China are: Baosteel fuel delivery system, length of 57km; Xiaolongtan continuous mining coal conveyor system; Shougang Iron Semi-continuous mining process water delivery system; Daliuta main adit coal conveyor, length 4 602m ; Temple River Mine, Shanxi Jincheng Coal Mining Administration, has a long 7 600m.
There is no doubt that research on a wide range of computer applications have a greater impact on the industry has grown. Review published on conveyor technology works, the main research and application technologies include: Conveyor Soft Start Control (S curve start); friction and wear and tear rolling simulation (visco elastic); kinetic analysis (wave and the mass-spring model) ; through non-destructive testing, monitoring of steel cord conveyor belt states: horizontal and vertical bend conveyor; booster to drive long distances underground conveyor; joint design and fault studies; conveyor belt cleaning and flip; conveyor belt transverse vibration prediction and elimination; narrow , high-speed conveyor belt; big dip and vertical conveyor; air-cushion belt conveyor; tubular conveyor; research experimental test device development; tensioning device.
1.2 to improve the design and running of conveyor
These studies include:
(1) conveyor start optimization theory;
(2) conveyor belt transverse vibration theory development;
(3) Rubber Loss Device;
(4) kinetic analysis and forecast conveyor belt speed of stress wave;
(5) to monitor the status of the monitor belt studies;
(6) The conveyor belt cleaning studies;
(7) rubber visco-elastic properties and adhesion studies;
(8) Discharge flow state trajectory and materials research.
1.3 to specifically study the situation
1.3.1 Theory of S-curve of the best starting
This study began in 1981, the Australian Commonwealth Scientific and Industrial Research Organization (HARRISION), optimization of the starting conveyor belt, so that the instantaneous stress minimized. In the starting time, S curve in the conveyor belt to generate a predictable dynamic stress. Transformation principle through the use of calculus in mathematics research, reached the S curve, which is the "start-up time in a certain minimum stress problems" a mathematical interpretation. These techniques used to solve problems and design of soft-start long-distance, high-speed conveyor belt. As the study results, published the first articles on small-bandwidth, high belt speed articles. Many companies in various forms to this new concept applied to the modern conveyors. Nordell proposed starting curve of the parabolic velocity, Dodge's Singh presented with a creeping segment of the starting process.
1.3.2 conveyor belt vibration theory development
During the 1980-1984, the pairs of orthogonal anisotropy thin plate theory study on the conveyor belt movement has emerged the phenomenon of vibration and bending the first mathematical explanation provides an accurate way to predict the return conveyor segment vibration of energy. Reached the four-order partial differential equations, and is applied to a specific sheet of the elastic boundary is called. Obtained a method for steel cord and fabric conveyor belt, forecasting a return segment with the transport segment and the vibration of the form of a special need to apply a different boundary conditions. The study can be designed to allow a free resonant vibration due to roller reduced to the extent arising from failures. Only a few companies use the research and design freedom of resonance HARRISON conveyor belt.
Vibration analysis of issues relating to conveyor belt has been incorporated into the "coal belt conveyor design specifications."
1.3.3 Loss of rolling
Conveyor belt tension controlled by many factors, such as raising the height, length, belt stiffness, indentation, conveyor belt through the roller deflection and additional resistance. In this regard, in the 20th century, 80 years ago, there are many documents, such as DIN22101 and CEMA, there is an internal calculation of conveyor belt manufacturer manual. The experimental results using these documents to a large extent determine the conveyor belt of the working point, such as the roller level, bending effects, as well as the tilt effect of a partial or overall friction.
In the 1980-2000 years, were predicted long-distance and turning conveyor friction new study. University of Newcastle (HARRISON, etc.) to study the material and the conveyor belt bending effects, and published a number of research results. During this period, ZUR, ALLES, HAGER, BETZ, SPAANS, JONKERS, NORDELL, LODEWHKS, who wrote the article is mainly reflected in the roller of tape on the sag resistance by the viscoelastic effects of scientific contribution.
SPAANS, HARRISON, ZUR, NORDELL, HAGE, etc. study is to bend and the related loss of the rubber roll sag characteristics of the understanding of the impact. University of Hannover HINTZ doctoral thesis (1993) take into account wear and tear with the indentation on the complexity of the situation.
Most of the study can be made early in the design of model system has been carefully reviewed, and thus more confidence in the enterprise. Thus, there have been long-distance conveyor with horizontal or vertical turning machines, as well as long-distance transmission over long distances, and mass transport to send the next plane.
1.3.4 Dynamic Analysis
There are several ways to solve the conveyor belt of elastic stress propagation issues, including the volatility model, the quality - spring model, the boundary element model and finite element / differential method. Each method has its own math based. For example, volatility model approach is necessary to consider all of the stress wave Fourier components, while the quality - spring model of the solution depends on the various modes to produce stress amplitude for the finite element model, when the use of a large number of computing to simulate the stress of If the element on the boundary errors when problems may occur, and the modulus of the elements will become critical of the modulus. Application of Volatility Models require more mathematical basis of the quality - spring model is easier to use high speed, large memory computer to handle.
In 1980-2000, the emergence of new research on this topic. In China, the belt conveyor dynamics analysis of the issues have been widely appreciated, Taiyuan Heavy Machinery Institute, Fuxin Mining Institute, China University of Mining and other units have carried out a number of theoretical exploration. Following the first author of this doctoral thesis, "Study of dynamic process of large-scale belt conveyor" (1996), after the completion of dynamics analysis software development, and in 2001 the software has been further developed to establish a complete kinetic model and the stability of numerical analysis. The software has been applied in engineering practice.
Dynamic analysis can estimate included in the starting or stopping the process of the relevant structures, roller and conveyor load. For the long distance and large tension conveyor, the method is an important part of the reliability of the design, which has been widely used in industry. Kinetic studies have been developed by a number of computer programs.
(1) The wave equation solving
In 1982, HARRISON for the first time described conveyor belt to solve the wave equation. This requires finding the conveyor belt carrying the branch and return branch to bear different loads when the wave equation of the characteristic function, and the static solution (stable operation of tension) and dynamic solution stack. Conveyor belt can be used to accurately predict the stress wave velocity. Models can not handle fluctuations in the movement boundary (tension), and the use of it requires special conditions. However, the volatility model as a tool to support design has been applied for many years.
(2) Quality - Spring Solution
Conveyor belt between the adoption of quality visco-elastic contact model consists of Noldell first proposed in 1984 and so on. Like other models, at its boundary element requires a corresponding stress and tension force, the calculation of this model may be unstable, resulting in erroneous predictions. Morrison, WBM discussed this instability. Spring - quality model is superior in dealing with fluctuations in tensioning device model. The world, many large companies are in the application of this method or to develop a computer program.
(3) The world-wide research
In kinetic analysis, along with the rapid increase computer speed fast, so that complex calculations possible. The following agencies have the ability to develop dynamic analysis program, or to purchase ownership of the program (for example, Beltflex). Such as the University of Hannover, Germany; U.S. Conveyor Dynamics Inc. (CDI): Beltflex; U.S. Conveyor Technologies, Inc.: Beltwin5; Flour Daniel (USA); Bechtel / Minenco (Australia); WBMPty. Ltd. (Australia), Belsim; Newcastle University (Australia); O'Donovan and Associates (Australia); Halpern Glick Maunsell Pry. Ltd. (Australia); Northeastern University School of Mechanical Engineering (Wei-Gang Song): BCD 2.0
1.3.5 Conveyor Belt Monitoring Study
Harrison was first invented in 1980, a new test method, and patented the method in the non-contact state of the steel cord conveyor belt to detect, monitor broken rope and wire rope fittings, forecasting possible damage.
The first pairs of steel cord conveyor belt to achieve non-destructive testing in Australia (1979). 1982-1987 This method is used in Germany, South Africa, Canada and the United States mining industry. This technique is also widely used in other industrial areas in order to improve reliability. According to this study, application of signal analysis theory, the further development of the standard tests and testing methods, in fact has been used for wire rope manufactured product quality inspection. Of its U.S. patents 4,439,731 and 4,864,233.
The application of this technology so that right dangerous and high-tensile steel cord conveyor belt monitoring possible, the safety belt can be tested. Through the magnetic field conditions and joint conditions, the wear coating can detect all kinds of manufacturing defects, such as the layout of rope spacing.
1.3.6 Joint Test and Test Device
From the three aspects of joint research, especially on high-strength (steel cord) conveyor belt, research focused on understanding the design of large joints, nondestructive testing equipment and optimize the joint strength. Including the joint-destructive testing devices, geometry and mechanical design, dynamics, effects of testing and research.
University of Hannover dynamic strength of joints was the first to study the contents of a part of it is to determine the joint life and seek to reduce conveyor belt strength method. They established the test-bed for research and testing of joints fatigue strength and to seek ways to improve joint strength.
At present, only limited examples of using the theory of joint design, but industry to improve the joint strength requirements. In addition, the intensity of issues such as bonding, and also conducted extensive research. Nordell using finite element analysis (FEA) study of a variety of wire rope fittings designed for the stress distribution.
1.3.7 conveyor and buffer the impact of research
Hard Rock contributed to the impact of the conveyor belt conveyor belt conveyor belt vertical tear and reduce the life of an important factor, especially in China, due to lower ore grades, so the hardness of minerals is higher than foreign ore, this article first Master of the author dissertation proposes a group of rollers in the roller additional buffer between the spring buffer method, and conducted experiments. Main duties include: (1) is equivalent to the quality of roller theoretical calculation; (2) to compare the effect of various forms of the buffer; (3) proposed additional spring intermediate buffer measures.
Two special belt conveyor System
2.1 The traction rope belt conveyor
Prior to 1980, has been widely used in wire rope traction belt long-distance, large lifting height occasions. This conveyor with two wire rope as a traction device, carrying materials from the conveyor belt.
Traction wire rope and the belt conveyor can be widely used in mining material handling business reasons: for long-distance transmission, can be achieved in the terrain limits the level of turn, conveyor belt easy to maintain, easy to replace. In the past 20 years, the wire rope traction belt conveyor company (Svedala), in the following areas developed wire rope traction belt conveyor systems: (1) Multi-rafter roll to reduce the noise; (2) PVL Conveyor Belt for pre-forming groove in order to enhance the stability of materials; (3) conveyor belt to enhance network; (4) the level of curve modules: (5) to examine the coverage layer and rope spinning-lun strengthening rope.
2.2 tubular and Vertical Lift Conveyor
For environmental protection reasons, there has been tubular belt conveyor, the conveyor belt inside the sealed material will. This technique required when flat conveyor belt through the roller type, hence the formation of tubular transitional section of pipe from the pipe into a flat type of transition section 3 above. This conveyor machine in good working condition to avoid throwing material, its structural form roller group can take many forms, such as 3 and 6 idler roller system. Domestic research and development began in tubular belt conveyor 80 in the early 20th century.
2.3 help drive belt conveyor
Various forms of help drive belt has become a common equipment used in underground, especially in the United States. Conveyor drive layout on several parts of the conveyor belt to reduce tension, conveying the process of discharge conveyor can also be achieved. In this way a long-distance conveyor can be built using low tensile strength of the conveyor belt, replacing the need for strong individual drive belt.
High productivity longwall mining needs of the beginning of a long-distance conveyor (> 5km), with the retreat mining need to shorten the length of the conveyor. Has developed to meet this requirement of the system, including PLC controls, tensioning devices, storage ring and a separate drive station.
For such long-distance, multi-drive system for dynamic control studies, require special consideration conveyor working conditions, such as the partial-load problems. Related to research in this area focused on the tensioning device of the friction and dynamics of control.
2.4 Conveyor Belt Flip
Flip turn on the control plane conveyor track has a good effect, maintaining conveyor belt and the idler friction between the characteristics of the same. Conveyor belt manufacturers have a lot of flip is given the length and studied the flip section of the conveyor belt strength and deflection of the issue.
2.5 The development of roller
Drum strength analysis and design and life analysis conveyor design is an important aspect. Many researchers are drum suppliers. At present the finite element tools have been widely adopted by the modern design of large-scale high-intensity drum also need the finite element method. CEMA has improved cylinder strength calculations.
2.6 air-cushion belt conveyor
The domestic air-cushion belt conveyor of 80 years began in the 20th century, carried out a large number of experimental studies and published many articles on research papers in the domestic air-cushion belt conveyor to form a hot, made air-cushion belt conveyor design methods.
3 Conclusion
This paper examines the current situation and in the belt conveyor belt conveyor system and design role. In the past 20 years, completed a number of landmark research and development work, application of these results produced by the equipment to meet the needs of the mining industry. Make use of computer models, measurement and theory testing with each other.