Scraper conveyor is a commonly used transportation equipment in coal mine production, which is widely used in coal face, transportation lane, connecting lane and ground transportation. Whether the scraper conveyor works normally or not plays an important role in the safety production of the whole coal mine.

Common faults and causes of scraper conveyor

(1) The quality of broken scraper chain is poor, that is, the quality of chain material and welding processing is not up to standard; too much coal is loaded or there is a large amount of coal pressing the scraper; the average load and large dynamic load repeatedly act, resulting in chain fatigue damage; the working face is uneven and not straight, scraper scraping is not straight, chute is not straight; the corrosive water under the well makes the chain ring rust, reducing the chain section and strength; the chain is too tight; The chain has long-term friction with the middle groove and sprocket, which reduces the diameter and strength of the chain section.

(2) The floating chain conveyor is uneven, not straight, with grooves; the scraper chain is too tight, squeezing the coal to one side of the chute; the scraper chain runs on the coal; the scraper is missing, bending too much; there is gangue under the scraper chain.

(3) The head of the chain falling off the chain sprocket of the scraper is not right, and the slide or base of the second section of the head is not smooth; the sprocket is worn out of the limit or bites into sundries; the tightness of the two chains is inconsistent, and the scraper is severely skewed; the scraper is too thin or excessively bent.

(4) The reducer of the scraper conveyor with the chain at the bottom of the scraper chain out of the slot is not straight, bulged and concave, and excessively bent; the length of the two chains is different, which makes the scraper skew; the chute is seriously worn; the scraper is excessively bent, which makes the distance between the two chains shorter.

(5) The gearbox is overheated, leaking oil and making abnormal noise. The gear is excessively worn, poorly meshed, improperly repaired and assembled; the bearing is damaged or the shaft is displaced; the oil quantity is too little or too much, the oil quality is not clean, the cooling is not good, and the heat dissipation is not good; the sealing ring is damaged, the joint surface is not tight, and the bolts of each bearing cover are loose; the coupling is improperly installed, the corner screws are loose, and the operation is overloaded; the gear is poorly meshed, The gear is seriously worn or damaged; there are metal sundries in the box.

(6) The sprocket assembly is overheated, the oil leakage seal is damaged, the lubricating oil is not clean; the bearing is damaged; the oil quantity is insufficient; the sealing ring is damaged or the oil seal is damaged; the gland or the pressing plate bolt is loose; the sealing ring is improperly installed and the fitting is not tight; the cylinder plug is loose.

preventive measure

2.1 precautions in use

Correct installation, timely maintenance and reasonable use can ensure the long-term stable and safe operation of scraper conveyor.

（1） When the scraper chain is installed, the connecting bolts shall be rustproof, the adherents shall be cleaned, and the grease shall be applied; the welding joint of the vertical ring of the ring chain shall be away from the middle plate, and the welding joint of the horizontal chain ring shall be toward the central line of the chute without twist; the screw fastening position shall be away from the middle plate; the large arc concave surface of the scraper shall be consistent with the transportation direction of the conveyor; the screw tightening torque shall be 60 ～ 70N? M; the chain shall be used in pairs. During maintenance, tighten the nuts frequently; correct and replace the bent or broken scraper in time. After the scraper chain is initially installed or operated, the elastic elongation of the initial tension pre addition shall be equal to avoid the chain relaxation. If the initial tension is too small, the chain will be slack, resulting in "feed chain"; if the initial tension is too large, increasing the running resistance will affect the service life of the chain.

(2) When the reducer is assembled, the side clearance and axial clearance of the gear can be adjusted with the help of the adjusting plate. After running for 200H with load, the oil in the box must be cleaned and replaced with new lubricating oil, and then replaced once every half a year. During maintenance and use, check the vent plug once a day to ensure smooth flow; check the oil temperature twice a shift and monitor the sound twice a week; remove the adsorbate on the magnetic oil plug once a week; replace the damaged gear in pairs; replace the lubricating oil when the content of foreign matters in the oil exceeds 2%, the metal abrasive exceeds 0.5% or the water content exceeds 2%.

(3) The liquid injection range of the limited torque hydraulic coupling is 40% - 80% of its working chamber volume. When the liquid injection quantity exceeds the upper limit, the motor cannot be started under heavy load. When the load suddenly increases, the motor will stall and get stuck, and the temperature will rise sharply due to overload during operation, the internal pressure will increase, causing leakage and even mechanical damage. When the liquid injection quantity is lower than the lower limit, the starting ability of the electric motor will be weakened, the transmission power and efficiency will be reduced, and the bearing will not be fully lubricated, Early damage due to noise; fusible plugs cannot be replaced by wood plugs.

2.2 preventive measures for common faults

(1) The chain of scraper chain is blocked or dropped to ensure that the scraper, connecting ring and connecting parts are complete and fastened; the scraper is bent and replaced in time; the chain is tensioned properly; the chain is classified according to the use time and wear condition to prevent the condition difference from being too large for use together; large sundries or large pieces of coal are removed in time; when moving the fuselage, do not bend too large, and the bottom plate shall be flat to prevent the chain from being blocked.

(2) The quality of scraper chain is strictly controlled, and the welding ring chain is used; the daily maintenance is strengthened. When changing shifts every day, the deformed and damaged chute must be handled in time; the pulverized coal, tail pulverized coal and other sundries on both sides must be removed; the worn and severely corroded parts such as connecting ring and connecting bolt shall be replaced in time; the working face or roadway at the installation site shall be straight, The mutual deviation angle between the two middle grooves is within 3 °; before the start of the conveyor, it is forbidden to load coal, and it must be loaded after the conveyor operates normally; during the test run, the length of the chain shall be adjusted by the method of tightening the chain to make it slightly arc at the bottom chain of the head, the length of both sides of the scraper chain must be the same, and it is forbidden to twist.

(3) The overload management of scraper conveyor shall be strengthened, and the equipment shall be maintained in strict accordance with the intact standard to prevent the equipment from being buried by coal. Strengthen the professional education of operators, further improve the quality of mechanical and electrical operators, and fully grasp the equipment performance.

(4) Check the bearing lubrication before checking the meshing clearance of the first and second level gears when the engine is hot; if the bevel gear is loosened by the wooden stick, the meshing is not good; if the bevel gear cannot be moved, and the oil cover cannot cover the seam, the thickness of the metal ring shall be reduced.