Introduction
With the continuous improvement of China’s modernization level in recent years, the total economic demand for energy has increased significantly, resulting in certain changes in China’s energy structure, but the overall demand proportion for coal has not decreased significantly. The coal washing plant is the main production enterprise of coal washing and dressing. With the increase in coal demand, higher requirements are put forward for the coal washing technology of coal washing plants, and higher technical standards are put forward for the operation stability of coal washing plants. With the help of safe and reliable technical transformation and application management, the operation effect of the belt conveyor in a coal washing plant can be ensured to the greatest extent. The common safety accidents of belt conveyors in coal washing plants are analyzed as follows.
1 Overview of safety accident types of belt conveyor in coal washing plant
From the perspective of structural type, the belt conveyor in a coal washing plant mainly includes the motor, reducer, frame, check equipment, sweeper, belt, and other types of devices. Because this equipment is widely used in coal washing plants, different types of coal washing plants also have corresponding requirements for the type of belt conveyor in the coal washing plants. Most coal can be divided into anthracite, bituminous coal, and lignite, which are common materials. The particularity of the coal washing plants in the operation process determines the high requirements for safe operation. The common safety risks are summarized as follows.
1.1 Accidents during operation
During the operation of the belt conveyor in the coal washing plant, there will be the problem of instability under the head roll. If the belt cleaner is derailed, it may lead to personal accidents and safety risks.
1.2 Conveyor accident cleaning process
During the use of the belt conveyor in the coal washing plant, the L head of the conveyor and the machine wool rotate at some positions for four years, resulting in the accident of getting involved in the belt and hurting people.
1.3 Belt deviation accident
Belt deviation is mainly the scraper conveyor belt during the use of the tail drum coal shaking, resulting in the drum rolled up a shovel, causing people to be belt away and serious safety incidents.
1.4 Accident of insufficient coal stacking protection
Coal burying accidents are caused by inadequate coal stacking protection, operators leaving their posts without permission, or sleeping on their posts.
1.5 Accidents of shift coal skin
In the process of shifting the coal skin, one person enters the inside from the outside. At this time, the operation of the upper chute ram is not in place, resulting in coal leakage and the burying of personnel in the lower chute.
Combined with the above analysis, it is not difficult to find that the safety accidents of belt conveyors in coal washing plants are often closely related to the misoperation of operators. In addition to the irrational operation of personnel, some parts need to be changed in the process design, including inadequate safety considerations and higher requirements for the technical level of operators, which are not conducive to improving the operation safety of the belt conveyor in the coal washing plant.
2 Analysis on safety transformation of belt conveyor in coal washing plant
The safety technical transformation of the belt conveyor in the coal washing plant mainly includes the following aspects.
2.1 Belt cleaner reconstruction
The belt cleaner is reformed and the traditional China belt conveying equipment is analyzed in advance. Most of them choose polyurethane materials and horny angle iron for technical settings. Its main working principle is that during continuous operation, the contact pressure can be adjusted with the help of the cleaner to remove the materials on the belt surface in time. Due to the direct contact between the sweeper and the tape, it is necessary to avoid the bad wear of the tape and improve the actual service life of the tape.
On the other hand, after running for a certain period, technical adjustment needs to be carried out in time. The actual effect during operation may affect personal safety. Therefore, it is necessary to pay attention to the cleaning effect of the belt cleaner. If the effect, it should be handled in time, otherwise, it will lead to belt deviation and more serious safety accidents. In the actual transformation process, it can be solved by referring to the design mode of the pneumatic belt cleaner and installing the air duct in the front of the machine head guide roller, which can intervene the high-pressure air and maintain an appropriate distance between the air duct and the bottom belt. At this time, the direction of the air outlet is opposite to the bottom movement of the belt, and the materials on the surface of the belt can be cleaned. When conveying dry materials, it is necessary to add a spray device to the front, actively open the pneumatic belt cleaner, and blow the mat erial on the belt into the chute, not only to solve the problem of surface drying but also to control the effect of dust.
2.2 Technical transformation of coal stacking protection
Coal stacking protection is an operation link that cannot be ignored in the use of belt conveyors in coal washing plants. At this stage, coal stacking protection mainly adopts a coal stacking probe to operate and seal the mercury contact into the sealed container. At this time , the head chute will face the coal stacking, and the relay will work after the upper probe tilts, to realize an accurate shutdown. However, in the actual use process, due to the setting and stability of the universal joint, it is easy to misoperate in advance without conditions, which seriously affects the production process, leads to centralized parking, and even leads to greater safety accidents.
The technical transformation of coal stacking protection can be adjusted by adding an RTX anti-rotation switch. After the technical upgrading, wind blades can be set at the head and chute in combination with the actual situation of the site. After the belt is opened, The blades will continue to rotate. At this time, the coal stacking will stop under the influence of stop action. At present, the application effect of this technology has been verified.
2.3 Transformation of inclined belt conveyor
In the process of using an inclined belt conveyor, coal often falls off the track and falls to the ground. At this time, it needs a manual operation and then put back into the belt, resulting in low production efficiency and higher requirements for safe operation . The technical transformation of this section can be handled by adding a sweeping pipeline at the lower part of the belt conveyor, and the problem that the pipeline is not introduced into the plant can be well solved by flushing the coal at the lower part of the belt into the collection box at the tail of the belt conveyor.
In addition, after the belt is tensioned, new damping devices will be added to the outside of the device and the lower part of the ground to avoid the problem of inadequate flushing water treatment, to significantly improve the stability of the device.
2.4 Transformation of coal retaining skin
The main function of the coal retaining skin is to solve the problem of coal overflow caused by the chute falling. From the structural point of view, it is also an indispensable part of the conveyor. At this stage, most of the coal retaining flaps of Belt conveyors are connected with steel plates using bolts. The coal retaining flaps need to be replaced at intervals. The problem of bolt fixation needs to be fully considered in the replacement process. If it is not handled in place, there may be potential safety hazards .
For the technical transformation of this section, the way of punching instead of screw connection can be adopted for stable treatment, and the adjustment requirements of installation tightness can be met with the help of the cam principle. Through technical transformation, the coal retaining skin can be strengthened using punch in connection, which not only has the advantage of convenient disassembly but also can adjust the tightness in combination with the actual production requirements to avoid material overflow.
2.5 Safety protection transformation
The problem of inadequate safety protection is common. It is necessary to implement the protection transformation of the head and tail of the belt conveyor. The spacing of the protective fence before the transformation is unreasonable, which is prone to personal safety accidents. In the process of implementing the transformation, give priority to solving the unreasonable situation of the drum, adjust the protective fence, and manage the machine head at the same time, to avoid unknown dangers when people enter the lower part of the machine head and tail. At the same time, it should also ensure that people cannot directly contact the drum. When setting the pedestrian side, it is necessary to add the number of steel pipe layers according to the requirements of the belt, and it is appropriate to add 2 ~ 3 layers of steel pipe. In the process of walking, if there is an accidental rotation of the guide belt, people are blocked by steel pipes and other adverse effects, and people are unable t o contact the supporting mixer, the injury and adverse effects can be reduced through technical transformation.
After the technical transformation, the operation stability of the belt conveyor in the coal washing plant has been effectively improved, and there are no problems related to people touching the rotating parts in the operation stage of the belt conveyor. At the same time, after the adjustment of the CAM technology, the tightness of the installation has also been strengthened, and the operation reliability of the equipment has been improved, which has created conditions for ensuring the scientific operation of the belt conveyor in the coal washing plant and improving the return on investment.
3 Conclusion
To sum up, the coal washing plant needs to face a variety of complex working conditions when dealing with different types of raw coal. There are many types of internal mechanisms and complex structures, which have high requirements for the technical level and safe operation ability of operators. To further improve the overall level of safety production of coal washing plants and better adapt to the requirements of continuous development of energy reform, we must do a good job in daily maintenance and management, continuously improve the technical level of coal washing production, and adopt technical transformation and other means to maintain advanced production relations, to lay a solid foundation for the stable development of the industry.
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