With the continuous development of the times, the belt conveyor coal conveying system has been continuously improved, the conveying distance of the conveyor has gradually increased, the conveying speed has also been continuously improved, and the driving power of the system has also been continuously improved. The reasonable design of the coal conveying system of the belt conveyor is very important, which plays an important role in reducing the cost of the equipment of the coal conveying system, the operating cost of the conveyor and the failure rate of the coal conveying system.

With the continuous development of the times, the belt conveyor coal conveying system has been continuously improved, the conveying distance of the conveyor has gradually increased, the conveying speed has also been continuously improved, and the driving power of the system has also been continuously improved. The reasonable design of the coal conveying system of the belt conveyor is very important, which plays an important role in reducing the cost of the equipment of the coal conveying system, the operating cost of the conveyor and the failure rate of the coal conveying system. This paper will discuss and analyze the overall arrangement of the coal conveying system of the belt conveyor, the finalization of the system belt speed, the tension device of the relevant soft start mode and the arrangement of the driving device, and draw the best scheme plan, which can be used as a reference for similar projects.

1 Long-distance belt conveyor coal handling system described
Dongqu Mine in Gujiao City, Shanxi Province is located along the Fenhe River at the southern end of Gujiao City, and Gujiao Power Plant is located along the Fenhe River at the northern end of Gujiao City, with a displacement distance of about 7500m. In order to reduce the noise and environmental pollution caused by the transportation of coal mines, as well as to reduce the transportation cost of coal and other reasons, through the choice of comparison, the railway transportation and ground belt transportation mode are excluded, and the underground channel transportation mode of coal mine is selected. In 2012, the project was completed and put into production. At present, the coal transportation system is in good condition without major accidents, which greatly improves the external transportation conditions of raw coal fuel in Dongqu Mine, Shanxi Province, and has achieved considerable economic benefits, social benefits and environmental benefits.

2 Determination of bandwidth and belt speed of belt conveyor coal handling system
The transport rate of the belt conveyor coal conveying system is proportional to the bandwidth of the conveyor belt and the belt speed, and the transport roadway section of the coal conveying system is closely related to the belt bandwidth of the system. If you want to increase the bandwidth of the belt, you must increase the section area of the conveyor roadway and increase the investment in infrastructure. Properly improve the system belt speed can reduce the system bandwidth and reduce the cross-sectional area of the conveying roadway, but also can reduce the weight of the conveyor transport system pressure, to reduce the belt strength and speed reduction ratio of the purpose, thereby reducing the capital investment in the project. But there will be new problems, the speed is too high corresponding to the manufacturing and quality requirements of the coal conveying system will be relatively high, and will also affect the ventilation of the roadway, the system with high speed, the roadway ventilation is not stable, easy to cause coal dust all over the sky, the roadway air impact. Therefore, considering the manufacturing quality of the system, the ventilation safety of the roadway and the infrastructure investment of the system, according to the design selection manual of the fixed belt conveyor coal conveying system, the belt bandwidth of 1m and the system speed of 4 m/s are finally adopted.

3 Long-distance belt conveyor coal handling system layout
Through the comparative analysis of the characteristics of the coal conveying channel, the belt conveyor coal conveying system has two layout schemes.

Scheme 1: only one coal conveying system is set up in the whole coal conveying channel, but the conveying distance will be relatively long. Its advantages are to reduce the transfer process in the system, reduce the coal dust and blockage caused by mutual transfer, and reduce the probability of accidents. Moreover, no transfer chamber is set in the coal transmission channel, so the power supply and distribution control of the coal transmission system is simpler, and the infrastructure and investment in the system can be reduced. Moreover, the daily management of the system will be more convenient because the channel is longer and there is no transfer device. However, the shortcomings of the first scheme are also obvious. The transportation distance of the coal conveying system of the belt conveyor is relatively long, so the requirements for the manufacture of the entire equipment of the conveying system, the driving power of the system, the investment in the system equipment and the strength of the belt are relatively high;

Scheme 2: Two belt conveyor coal conveying systems are set up in the whole coal conveying channel, and the transfer and transportation of coal materials can be realized by overlapping the two systems, thereby reducing the conveying distance of each conveyor coal conveying system. Its advantage is that there is a transfer process in the middle of its conveying system, so it can shorten the conveying distance of each conveying system, thus reducing the requirements for the installed power, investment cost and tape strength of each conveying system. However, its shortcomings are also obvious. Because there is a transfer process in the middle of it, a transfer grounding chamber must be set up. Because the top of the transportation channel is Gujiang City or the riverbed of Fenhe River, the system is not only difficult to support, but also the capital required for its infrastructure is increased. Moreover, the driving system equipment in the middle is far away from power supply and distribution, and the control process is more complicated, this increases the investment cost of the electrical system, and the maintenance of the system equipment is more cumbersome.

Obviously, considering the two schemes, it is decided to adopt the method that only one coal conveying system is set up in the whole coal conveying channel.

4 Tension mode of driving device of coal conveying system
There are two tightening modes for the driving device of the coal handling system. First of all, the heavy hammer and fixed tightening mode, the tension of this tightening mode is not adjustable, so it leads to the fluctuation phenomenon when the long-distance belt starts braking, which is not suitable for this design, so it is not considered. Second, the hydraulic winch automatic tensioning device, this way can automatically achieve the tape start when the tension is large, and in the normal operation of the tension to be small, in the system start when the loose edge of the tape can be timely Tighten, which can greatly improve the system to start efficiency, so as to prevent tape slippage, to meet the tape in the normal state of the tension of the different requirements.

5 Soft start mode of long-distance belt conveyor coal handling system
At present, the common soft start mode speed regulation hydraulic coupling mode, controllable start transmission mode and frequency conversion speed regulation system mode are commonly used in the market. The torque transmission capacity of the speed-regulating hydraulic coupling is largely determined by the amount of oil in the circulating circular cavity. The amount of oil in the circulating circular cavity is proportional to the torque transmission capacity of the hydraulic coupling. Moreover, the range of torque transmission force is also proportional to the speed adjustment of the hydraulic coupling, so the coupling speed and balance the power of the multi-machine drive can be adjusted by changing the amount of oil. However, there are also disadvantages. The speed regulation performance of the speed-regulating fluid coupling in the low-speed range is relatively poor, and there is a certain probability of slip loss, so it needs to be dissipated later, and the later maintenance of the hydraulic system is also difficult and the workload. It is relatively high, and the equipment covers a larger area.

6 Long-distance belt conveyor coal handling system summary
This chapter introduces the design of the long-distance belt conveyor coal handling system, analyzes and introduces the layout of the system, the belt bandwidth and belt speed, and the selection and arrangement of the driving device, and selects the optimal scheme from the comprehensive consideration of the advantages and disadvantages of the system for the reference of the relevant engineering.