Analysis And Treatment Of Common Faults Of Coal Mine Belt Conveyor

Conveyor Belt

China’s coal mines are mostly mined by well way, mostly long wall mining. Long wall mining not only has higher recovery rate of coal resources, but also has higher efficiency. In longwall mining, belt conveyor is an important coal transport equipment. Compared with locomotive transport, belt conveyor transport volume and can continue to transport, is an economic coal transport equipment. At present, almost all coal mines use belt conveyors when transporting coal. However, due to the poor underground environment of coal mine, high dust, narrow space, heavy task, coal mine belt conveyor will occur various faults. Failure of belt conveyor will affect coal output of working face. If the belt machine cannot be repaired in time, it is likely to lead to the production of the working face. Therefore, it is necessary to carry out timely maintenance for the failure of belt conveyor. This paper focuses on the belt conveyor in the running process of the common fault to expand, discusses the belt conveyor fault treatment method.

1 Common fault analysis of coal mine belt conveyor

Belt conveyor is a mechanical device that relies on the friction of the belt to transmit objects. It is mainly composed of conveyor belt, roller, driving roller, head frame, middle frame and tail frame, as shown in Figure 1. Belt conveyor is widely used in coal mining because it can realize the continuous transportation of objects. However, due to the harsh downhole environment and heavy transportation tasks, belt conveyor will occur various failures. Below, the common faults of belt conveyor will be analyzed in detail, mainly including driving motor failure, belt failure and support rod failure.

1.1 Drive motor failure

In the running process of belt conveyor, the driving motor is the main power source. Once the driving motor fails, the belt conveyor will run abnormally. The driving motor fault of belt conveyor is manifested as drive shaft fracture, motor burning, motor heating, motor abnormal vibration. The driving shaft of the motor may be broken because the service life of the belt conveyor is too long, resulting in serious wear and fracture of the bearing of the motor; The belt conveyor load is too large, more than the maximum bearing capacity of the motor, and then lead to the motor drive shaft fracture. There are many reasons for the motor burning, that is, the motor heat dissipation is not good resulting in the motor internal coil overheating; The load of belt conveyor is too large, which leads to the blocking of the motor. A short circuit in the power supply can also cause the motor to burn out. The cause of abnormal motor heating is that the heat dissipation outlet of the motor is blocked; There are harmonics in the power supply. The abnormal vibration of the motor is due to the loosening of some fixed screws inside the motor. If it is not handled in time, it may lead to the spreading problem of the belt conveyor.

1.2 Belt Faults

Belt is the core parts of the conveyor, and is the main implementation of transportation components. In the process of operation, the belt will occur some failures, common belt breakage, skid, spontaneous combustion and material, etc. There are many reasons for the broken belt :a) the belt is connected by polyurethane, and the position of the connecting port will fracture when the belt is not uniformly stressed; B) The belt is worn by friction with coal or rock during operation, which leads to the weakening of the tensile strength of the belt. When loading coal, if large coal or rock directly hit the belt, it may lead to local damage of the belt. Belt spontaneous combustion is a very bad problem, coal in contact with air oxidation and spontaneous combustion, which will lead to belt spontaneous combustion. The uneven local force of the belt will lead to the deviation of the belt and the scattering of material.

1.3 Idler failure

The roller is used to provide sufficient friction for the belt machine. In the running process of belt conveyor, the roller on the belt conveyor is easy to be damaged. The specific problems caused by the failure of the supporting wheel mainly have the problems of the belt machine running off, spreading materials. The roadway where the belt conveyor is located is relatively closed and dusty, which is easy to lead to the accumulation of a large amount of dust on the shaft of the roller, making the roller locally stuck. After the idler stuck, the belt cannot provide enough friction, which makes the belt in the local convex, easy to spread the problem. If a large number of gravel is stuck on the supporting rod, the height of the two ends of the supporting rod is inconsistent, and it is easy to appear the problem of belt machine running off. After the belt machine runs off the track, the material is very much, which is difficult to clean up in a short time.

2 Analysis of common fault handling methods of coal mine belt conveyor

The above analysis of the belt conveyor drive motor, belt and roller and other main components of the fault. It is necessary to deal with these faults effectively so that the belt conveyor can resume operation quickly. The following describes how to troubleshoot these faults.

2.1 Handling method of driving motor failure

After the failure of the driving motor, the belt conveyor will automatically stop running. At this time, the drive motor should be checked: a) close to the drive motor with nose smell, if you smell a mushy smell, check whether the motor is burned inside; B) Check the bearing of the driving motor to see whether there is a bearing fracture problem; C) Beat the shell of the motor with a wooden stick to check whether there is a loosening problem. The motor burnt out is difficult to repair, the damaged motor should be replaced. When replacing, it is necessary to estimate the load of the transmission line and belt conveyor of the motor and rule out the cause of motor burning one by one. For the problem of bearing fracture, the service life of the motor bearing should be checked first, and then the shape of the port should be checked to replace a new bearing. For the screw loosening problem inside the motor, the loosened position should be checked and reinforced.

2.2 Handling method of belt faults

The key point of belt fault treatment is to how to repair the broken belt. In case of belt breakage caused by aging, all belts should be replaced immediately. For the belt fracture caused by loosening of the connection, the fracture should be cut flat and the connection should be made again, and the polyurethane should be used to reconnect. For the broken zone caused by rock block damage, the broken zone should be cut off and notch connection should be made again. As for the lack of belt tension in the process of belt operation, the belt should be tightened. In addition, corresponding measures should also be taken to avoid belt burning can monitor the local temperature of the belt, to take local cooling measures, such as sprinkling. For the skidding problem in local areas, the right amount of fly ash can be scattered at the supporting rod.

2.3 Handling method of idler failure

It is difficult to find roller failure in the actual operation process, because the failure of the roller does not directly affect the operation of the belt machine. In order to find the fault of the roller in time, we should pay attention to the location of the material on the belt machine. In addition, it is necessary to carry out a comprehensive inspection on the supporting stick regularly, mainly through a special tool to move the supporting stick, to check whether it is stuck. For the stuck stick, it should be immediately removed to check the cause of the fault. If a foreign body is stuck, you can remove it by cleaning it. If the fault is caused by wear, it can be solved by replacing the belt.

3 Conclusion

Belt conveyor is an important auxiliary transportation equipment in underground coal mine, its normal operation is related to the smooth progress of coal mining. Due to the harsh environment of coal mine, the key components of belt conveyor will fail, mainly driving motor, belt and drag roller failure. For the faults of each key component, there are differences in handling methods. The main idea is to find out the cause of the fault and then rectify the fault. The research can provide some technical reference for fault treatment of coal mine belt conveyor.

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