Belt conveyor has the advantages of long conveying distance, large capacity, simple structure, convenient maintenance, low cost, strong versatility, reliable operation, easy automation and centralized control, and is widely used in high-yield and high-efficiency mines. Whether the belt conveyor can run safely and stably directly affects the normal production of coal mines. However, if the belt conveyor is not properly managed during operation, all kinds of faults will occur, and serious faults are accidents, which will pose a safety threat to equipment and personnel and even affect the normal production of the whole mine. According to many years' field practice, from the user's point of view, the causes, hazards and preventive measures of belt conveyor faults such as deviation, slippage, tearing, roller rotation and belt breakage are analyzed in detail, which has the characteristics of strong field practicability.
Keywords: coal mine; Belt conveyor; Fault; Accidents; Reason; Harm; prevent
With the continuous improvement of coal mining mechanization and the continuous increase of coal mining depth. The laying length of underground belt conveyor is also increasing, and belt conveyor has become the key transportation equipment of electromechanical integration technology and equipment in coal mining. In particular, the wire rope traction belt conveyor and the wire rope core strong belt conveyor are widely used in mines, and the retractable belt conveyor with a bandwidth of 1.2 m is used in high-yield and high-efficiency fully mechanized mining faces, which greatly improves the production efficiency of coal mines. However, if the belt conveyor is not well managed or used properly, various faults will occur, which will affect the transportation of raw coal if not handled in time. A serious fault is an accident, which threatens the safety of equipment and personnel and even affects the normal production of the whole mine. Therefore, it is very important to analyze the fault causes of belt conveyor in time and accurately, put forward the methods to solve the problems and formulate practical preventive measures, which is a powerful guarantee to ensure the safe operation of belt conveyor.
I have been engaged in the management of underground belt conveyor in Pingdingshan Coal Group 12 years, and have accumulated rich practical experience in my work. The author summarizes several common faults of belt conveyor, analyzes the causes of belt conveyor faults, expounds the hazards and consequences of faults, and formulates specific preventive measures, which has a guiding role for on-site management. 1. Belt Conveyor Deviation Fault (1) Cause Analysis of Belt Deviation
Belt deviation is the most common fault in the operation of belt conveyor. There are many reasons for tape deviation. The main deviation phenomena and reasons are as follows:
1. At some point along the length of the conveyor belt, the conveyor belt begins to move to one side. The reasons may be:
Roadway deformation, floor heave makes the frame incorrect, and the idler deflects; The roller, especially the lower roller, adheres to the material, resulting in uneven surface of the roller; There is too much coal accumulated in the lower belt, which makes the belt squeeze to one side.
2. The whole belt is biased to one side, the belt is worn, and the frame close to the drum grinds a groove. The reasons are: the drum installation is not parallel; The left and right tension of the belt tensioning roller is uneven; The belt is too loose.
3. The tape deviated to one side during operation, and the maximum deviation happened at the joint, which was caused by improper tape joint.
4. When the belt runs, it will run off at one or several places on the conveyor body. The reason is:
The idler is not installed correctly; Roller or rack is uneven; Idler is stuck; The degree of tape tension is different. 5. One or several parts of the belt run off at all points of the belt conveyor. The reasons are: the belt becomes bow-shaped; The seam is not straight.
6. There is no deviation when there is no load, but after loading, because the loading position is incorrect and the goods are biased to one side of the tape, which makes the load difference between the left and right sides of the tape too large.
7. The direction of belt deviation is uncertain because the belt is too loose.
8. The deviation of the belt at the unloading place may be caused by the different lateral pressures caused by the different contact degree between the belt coal retaining plate and the belt.
9. Mucus sticking to the surface of the drum will also cause the adhesive tape to fall off the drum. The reason is that there is a coal seam on the surface of the main drum or the tail drum, the diameter of the place where the drum sticks coal slurry increases, and the adhesive tape shifts to the end of the drum surface that sticks coal slurry.
10, the driving roller, the tail roller and the reversing roller are not parallel, resulting in deviation. The reason is that when adjusting the tightness of the tape, the tightness of the two stable tail wire ropes or lead screws is inconsistent, which makes the tape loose on the tail drum. 1 1. Incorrect feeding leads to belt deviation at the coal receiving point. The reason is that the loading and feeding at the transfer point is incorrect, and the coal block does not fall to the center of the belt, but deviates to one side, resulting in lateral thrust to push the belt to one side, resulting in deviation. 12. Deviation caused by tape quality problems. The quality of the adhesive tape is unqualified, the thickness is uneven, and the elastic stress of the whole adhesive tape is uneven. The deviation caused by it is difficult to adjust after installation and use. (2) Harm and consequences of belt deviation
1, belt deviation will cause mine fire. Belt deviation increases the running resistance of the belt, which makes the belt slip at the drum and heat up due to severe friction; The deviated tape edge rubs violently with the frame to generate heat; The deviation belt is heated due to strong friction with the thrown coal; The accumulation of spilled coal makes the idler not turn, and the idler whose belt does not turn for a long time generates heat, which may cause a mine fire accident. 2. Reduce the service life of the adhesive tape. Deviation of the tape, if not handled in time, will make the protective adhesive layer on the edge of the tape wear off, or the adhesive layer on the surface of the tape will be seriously worn, which will reduce the service life of the tape.
3, affect the civilized production of roadway, and increase the labor intensity of drivers. The deviation belt throws the coal on the empty belt and transports it back to the tail of the machine, which leads to the accumulation of a large amount of spilled coal at the tail of the machine, which increases the labor intensity of the tail-watcher to clean up the coal. Scattering a lot of coal in the roadway will affect the civilized production of the transportation roadway and the clean ventilation of the roadway. The deviation of the adhesive tape leads to the rapid wear of joints, which increases the labor intensity of maintenance workers and wastes materials due to the increase in the number of joints.
4. The serious deviation of the tape will cause the tape to tear and break, which will expand the accident. If the sweeper doesn't work, the tail drum will get stuck in the big gangue, which will cause the belt to be abraded and even torn and broken, thus causing the accident to expand. (3) Prevent the belt from running off.
1. Ensure the incoming quality of adhesive tape. Belt users must buy qualified products confirmed by the state to avoid deviation accidents caused by quality problems in belt manufacturing.
2. Install the belt conveyor correctly in strict accordance with the technical requirements. Attention should be paid to the installation dimensional accuracy of each device during installation. 3. Strengthen the sense of responsibility of drivers and maintenance personnel. Improve the quality of customized joints of maintenance personnel and improve the operating skills of drivers to correctly handle belt deviation.
4. Strengthen the on-site management of belt conveyor. Strengthen the patrol inspection in the class, handle the deviation in time, and prevent the accident from expanding. Adjust the uneven intermediate frame in time to make the idler bear evenly. Replace the sweeper skin in time, so that the floating coal on the empty belt will not be pulled back to the drum.
5. Install a coal scraper at the reversing drum and the tail drum to clean up the floating coal here in time to prevent the overflowing coal from sticking to the drum and causing the belt to run off.
6. Install and use the anti-deviation device. The function of the anti-deviation device is to stop the power failure immediately once the belt deviation is detected, and send an alarm signal to remind the driver to take treatment measures. Second, the belt conveyor skidding fault (I) the reason analysis of belt skidding.
The transmission of the belt depends on the friction between the belt and the driving roller. If the friction is too small, the roller is driven to rotate, and the belt cannot run synchronously or asynchronously. This phenomenon is usually called belt slip or simply "slip". Cause analysis of belt slippage;
1, the problem of wrap angle. For a given belt conveyor, it is a fixed value, which does not change with the change of environmental conditions, so it is not the main factor affecting belt slip in the field.
2. The belt tension at the driving roller is insufficient. The main reasons are: insufficient tension stroke and too loose belt; Weight of counterweight is not enough; The conveyor belt is too long and the tension is not enough; If the static tension device of the belt fails, such as the tension wire rope is pulled off, it will also cause slippage. 3. Reduce the friction coefficient. The main reasons are: the main drum is seriously worn or degummed, and the friction is small; When the contact surface between belt and drum enters water, coal slime, coal dust or lubricating oil, the friction coefficient will drop sharply; Insufficient belt tension, load starting, etc.
4. The running resistance of the belt increases. The main reasons are: overload "crushed" the tape; The rotation of the roller or drum is inflexible and uneven.
Don't turn; The friction between the adhesive tape and the floor or floating coal (gangue) is serious; The running resistance of the belt will be greatly increased due to the deviation of the belt at the tail drum, coal scattering, jamming, or material accumulation at the head. (2) The hazards and consequences of belt slippage
1. Slipping will accelerate belt wear and shorten its service life.
2. Slipping will slow down the running speed of the belt, and insufficient coal transportation at the end of the slipping belt will cause coal blockage; There is too much coal accumulated in the tail coal baffle, and the belt cannot be started.
3. The coal jam caused by serious slip makes the belt at the driving drum wear, and even wears off the belt.
4. After the belt slips with the driving roller, the driving roller will rub with the belt to generate heat, and the belt will be worn, burnt and burned out, which will burn the belt in serious cases and cause a mine fire. (3) Prevent the belt from slipping
1, strengthen the operation management of the belt conveyor, enhance the driver's sense of responsibility, and handle it in time if slippage is found.
2. It is forbidden for water, coal slime, coal dust or lubricating oil to enter between the roller and the lower belt, which will reduce the friction coefficient. 3, put an end to heavy load parking and start with load.
4. Use rubber roller or grooved roller to increase friction coefficient.
5. Adjust the belt tensioner, regularly check and adjust the heavy hammer tensioner or sports car tensioner to increase the tension of the belt and increase the friction.
6. Install and use the belt slip protection device. When the belt slips, it will send a signal through the slip sensor, automatically cut off the power and send an alarm signal to remind the driver to take treatment measures. Third, the belt conveyor tearing failure (I) Causes of belt tearing failure The main reasons for belt tearing are:
1, the belt conveyor meets external sharp objects, such as steel, anchor, iron, I-beam, large pieces of gangue, etc. Poke into the belt, causing the belt to be scratched, and in severe cases, the belt will be torn.
Due to serious deviation, the belt was torn. Generally, only the edge of the tape tears, and it will not appear inside the tape. 3. The grate at the silo mouth is worn or damaged, or the size is unreasonable, which leads to the direct impact of gangue and coal on the adhesive tape. 4. Each drum is stuck by gangue and other items, and the adhesive tape is torn.
5. The strength of the adhesive tape joint is too low or the load is too large, and the joint clamp is corroded or the adhesive tape is corroded and broken, which leads to the tearing of the adhesive tape at the joint and the longitudinal tearing of the adhesive tape. (B) the hazards of tape tearing failure
1, tearing of adhesive tape accelerates belt wear, shortens belt service life and wastes resources;
2. A large amount of coal is scattered in the transportation roadway due to the tearing of the adhesive tape, which affects civilized production and increases the labor intensity of employees; 3, tape tear, stop production for emergency repair, affect the whole mine production; (3) Prevent the adhesive tape from tearing.
1, to prevent the tape from deviating and tearing.
2. It is forbidden to haul large pieces of gangue by belt conveyor, and it is forbidden to haul steel beams and hydraulic props by belt conveyor. , so as to avoid the belt tearing caused by the blockage of other foreign objects.
3. Take effective measures to prevent foreign objects from entering the adhesive tape. Control large pieces of coal gangue and anchor rods from the mine source to prevent sharp objects such as anchor rods from poking into the adhesive tape and causing longitudinal scratches or tears of the adhesive tape.
4. Enhance the sense of responsibility of belt conveyor drivers and inspectors. In particular, drivers at coal feeder outlets or coal bunker outlets should pay attention to observation, repair worn coal troughs in time, and avoid gangue and coal blocks directly hitting the adhesive tape.
5, change the coal hole and coal bunker construction technology. The support of coal chute and coal bunker should be supported by long anchor rod to prevent the coal bunker wall from being scratched or torn when the anchor rod falls off into the coal stream after being impacted by the coal stream.
6. Change the way of burning coal. Direct injection of coal flow into coal troughs and coal bunkers should be avoided, and landslide roads should be built in coal troughs and coal bunkers to buffer coal flow.