Chevron conveyor belt is a large electric mechanical equipment widely used in coal transportation. It has the advantages of simple structure and good transportation economy. With the continuous development of the conveyor in the direction of long-distance, large transportation volume and high belt speed 0, the conveyor belt often deviates during operation, resulting in faults such as large-area scattering and belt tearing. In order to ensure the stability of operation, the running speed of the conveyor has to be reduced appropriately, which affects the efficiency of coal transportation.
It is found that the deviation of the conveyor belt is mainly caused by the uneven running direction of the conveyor belt. The deviation of the conveyor in the transportation process includes small deviation within the safety range and a large number of deviation beyond the safety range. For different deviation phenomena, the stability of the conveyor in the operation process is significantly improved by adopting the schemes of self-aligning supporting spoke and turbine and worm self-correction. The practical application shows that the new intelligent deviation correction device can increase the material transportation speed of the conveyor belt by 27,4% and reduce the deviation rate by more than 93.5%. It is of great significance to improve the stability and economy of underground material transportation in coal mine.
Analysis on the causes of belt deviation
Through the stress analysis of the conveyor during operation, the reasons for the deviation of the conveyor during operation are mainly caused by two factors.
One: the force of the conveyor belt in the width direction exceeds the reverse resistance that the roller can give. When the conveyor runs, the resultant force of the external force is and the reverse resistance of the roller group to the conveyor belt. When the two are equal in size, the conveyor belt will not run off. When the external force is less than the reverse resistance of the idlers, the system will run normally along the bottom of the idlers under the action of material gravity. When the resultant force of external force is greater than the reverse resistance of the roller group, the conveyor belt will deviate and deviate to the outside of the roller group along the direction of external force, resulting in the deviation of the conveyor belt.
The conveyor belt is an object with viscoelastic characteristics. Therefore, when the internal tensile stress distribution is uneven, the conveyor belt will move slowly towards the side with large tension, making the conveyor belt offset.
Above two running deviation caused by many factors, such as frame deformation, not flat, conveyor belt conveyor belt joint wear, etc., will cause the above problems, and these problems are inevitable in the process of conveyor running, so you need to use a certain correction device to adjust the conveyor belt running state, meet the demand of the running stability of the conveyor belt.
Rectify deviation of self-aligning roller
Self-aligning bracket is a new type of bracket and spoke group with self-aligning ability, which can adjust the running state of conveyor belt to some extent.
Self-aligning roller group mainly consists of vertical roller, upper and lower support frame, middle roller and side spokes, all rollers are installed on the upper support frame, the upper support frame can rotate around the lower support frame. When the conveyor belt has deviation in operation, the conveyor belt will contact the vertical wheels on both sides, which will generate pressure and drive the rotary roller. The spoke will drive the upper support frame to shift around the lower support frame under the action of the force, changing the force of the conveyor belt, and then realize the adjustment of the conveyor belt offset.
Since the self-aligning roller rectification of conveyor belt belongs to the passive action, low efficiency, small amount of rectifying and mainly in view of the conveyor belt deviation less running deviation, unable to meet the demand of conveyor belt large offset of rectifying, so need to study a new active action plan, to adapt to the long distance, large capacity, high speed conveyor rectification requirements.
Active deviation correction scheme
In order to meet the demand of rectifying deviation of conveyor belt with large deviation, a worm wheel and worm type active rectifying device is proposed in this paper.
The active deviation rectifying device mainly includes upper support frame, roller set, conveyor belt deviation monitoring device, lower support frame, worm gear and worm device, servo motor control system. Conveyor in the process of running, the monitoring device by wandering on the conveyor belt running deviation of the real-time monitoring, and then analysis of monitoring information is passed to the control system, control system based on conveying the excursion of signal adjusting control, drive worm gear and worm gear to run, drive the support frame in a certain Angle, so as to realize the adjustment of the conveyor belt partial displacement situation. The active rectifying control system has the advantages of simple structure and good adjustment precision, and can quickly adjust the deviation of the conveyor belt to meet the smooth and normal operation requirements of the conveyor.
In practice, the active deviation correction scheme can be used in the process of solving the problem that the conveyor belt should be fast under the rolling simplification at high speed. High adjustment accuracy, but for the tong degree in the area, due to the speed of the partial. High frequency, only the correction scheme is difficult to achieve fast adjustment, this, and transport in and transport other fast adjustment mode for supplementary adjustment.
In view of the current situation that the conveyor system often appears deviation in the process of transportation, which affects the normal transportation of materials, a new intelligent deviation correction device for belt conveyor is proposed based on the analysis of the reasons for deviation of conveyor belt. According to the actual application,
1) The force of the conveyor belt in the width direction exceeds the reverse resistance given by the rolling energy and the uneven distribution of tension in the conveyor belt is the main reason for the deviation of the conveyor.
2) The self-aligning roller’s rectifying of the conveyor belt belongs to passive rectifying, with low efficiency and small rectifying amount, mainly for the conveyor belt with small running deviation.
3) Automatic deviation correction device of worm gear and worm belongs to active deviation correction, with high adjustment efficiency and large amount of deviation correction, mainly for the conveyor belt with large amount of deviation running.
4) The new intelligent conveyor belt deviation detection system can realize the accurate monitoring of the conveyor belt’s 5mm offset, laying a foundation for the rapid deviation correction of the conveyor belt.
5) The use of coal owner’s well for nearly 6 months shows that the new intelligent deviation correction device can increase the material transportation speed of conveyor belt by 27.4% and reduce the deviation rate by more than 93.5%, achieving good effect in improving the stability and transportation efficiency of coal and material transportation in underground coal mine.