The working environment of open-pit coal mine is harsh. During the working process, under the influence of pulverized coal accompanied by materials and pulverized coal produced by secondary crushing, the bearing labyrinth seal and lip seal fail, resulting in pulverized coal entering the bearing cavity, hindering good bearing lubrication, intensifying bearing wear until completely damaged. In order to solve the above problems, through the optimization of the bearing seal of the original crusher, in the case of not changing the installation size, increase the labyrinth end ebony, change the direction of the labyrinth seal end, change the radial direction to the axial direction, and increase the lip seal axial space, from one lip seal to two, so as to effectively prevent coal powder from entering the maze until the bearing cavity. It improves the sealing of the bearing chamber, prolongs the service life of the bearing and improves the stability of the equipment. In recent years, mineral sizers has been widely used in the crushing of raw coal in open-pit coal mines. With advanced technology, excellent performance, easy to use, low failure rate and small maintenance, mineral sizers has won the trust of enterprises and brought significant economic benefits to open-pit mines. mineral sizers are the most important part of raw coal crushing equipment in coal mines. The rated crushing capacity of each unit is 1500t/h, and the two units total 3000t/ h. The crusher is composed of crushing system, power system, lubrication system, control system and other auxiliary systems. The feeding particle size of the double-toothed roller screening type secondary crusher is 300mm×300mm×300mm, the particle size of greater than 300mm and less than 500mm is not more than 5% : 98% of the discharge particle size is less than 50mm, and the particle size of the single direction is not more than 65mm. The wear-resistant lining plate is provided in the easy wear part of the chute, the thickness of the lining plate is not less than 6mm, the crusher has a safety protection device and positive and negative rotation function, with the function of rapid discharge, uniform discharge particle size, small fluctuation and convenient replacement of wearing parts. The electrical protection of the whole system equipment is complete and perfect. The bearing of the crushing roller is the main part of the equipment, and the service life of the bearing directly affects the normal operation of the crusher. Due to the harsh working environment, the field dust is very large, the bearing seal problem of the crusher is particularly important, its reasonable structure and sealing effect is good or bad, directly affect the service life of the entire equipment. Advanced equipment needs scientific management, only the correct use, maintenance and maintenance, in order to play its advanced nature. After inspecting the skeleton oil seal and labyrinth seal of the damaged bearing of the crusher, it is found that the bearing roller is seriously worn, the inner skeleton oil seal is seriously worn, the seal fails, the metal labyrinth seal fails, the equipment runs for a long time, and foreign matter such as coal powder enters the skeleton oil seal along the gap, causing damage to the skeleton oil seal. Due to the coal powder into the raceway, resulting in insufficient lubrication of the bearing roller, the rolling body blocked, with the increase of foreign matter, resulting in the rolling body stuck, bearing inner and outer rings and rolling body friction and wear. The direct cause of bearing damage is the failure of the labyrinth seal, the design structure is unreasonable, the coal powder is easy to enter the labyrinth, resulting in grease can not enter, thus damaging the lip seal, the coal powder directly into the bearing cavity, resulting in bearing damage. In order to improve the sealing performance of labyrinth seal and the life of lip seal, it is necessary to reform labyrinth seal.
Third, mineral sizers bearing damage cause analysis
1. Analysis of the labyrinth seal damage After checking the labyrinth seal of mineral sizers damaged bearings, it was found that there was a large amount of mud and pulverized coal in the labyrinth path, and the labyrinth path had been worn. When looking for the reason of coal powder entering the labyrinth, it is found that the labyrinth end face of the static labyrinth seal is short, and the labyrinth path is radial when the dynamic labyrinth seal is matched with it, which leads to the coal powder easily entering the labyrinth. In this way, long-term operation wear causes the maze to widen, and the coal powder is easier to enter, resulting in the failure of the maze.
2. Lip seal failure analysis Due to the failure of the labyrinth seal, after a long time of operation, the internal lip seal is affected by the coal powder, the lip surface wear is intensified, and the rubber is aging, resulting in the lip seal failure.
3. Damage cause analysis of crushing roller bearing (1) Analysis of internal factors of bearing chamber. During the inspection after the disassembly of the equipment, it was found that the bearing roller was seriously worn and appeared in a square shape. As foreign bodies such as pulverized coal entered the raceway along the gap, the bearing roller was not sufficiently lubricated and the rolling body was blocked. With the increase of foreign bodies, the rolling body was stuck, and the inner and outer rings of the bearing and the rolling body were friction and wear. (2) The bending deformation effect occurs when the crushing roll is running. When the crushing roll is rotating, the crushing roll has a slight flexible deformation due to the influence of the material, and the vibration of the equipment has a certain impact on the normal operation of the bearing. (3) Impact of crushing roller bearing lubrication system. Crusher bearing centralized lubrication of insufficient oil or pipeline blockage, resulting in poor bearing lubrication, accelerated bearing wear, resulting in bearing damage.
4. Failure analysis results of crushing rod bearing Through the inspection of bearing rolling body and inner and outer rings, it is found that the rolling body is seriously worn with square shape and raceway wear of inner and outer rings. The direct cause of bearing damage is the failure of inner skeleton oil seal and outer metal labyrinth seal, the equipment runs for a long time, and foreign matter such as coal powder enters the raceway along the gap, resulting in poor bearing lubrication. The blocking of the rolling body, coupled with the abnormal vibration caused by the operation of the crusher, with the increase of foreign matter, the rolling body will be aggravated by wear, bearing stagnation, friction and wear between the inner and outer rings of the bearing and the rolling body, and bearing high temperature damage.
Fourth, mineral sizers improvement plan
1. Optimize labyrinth seal structure (1) Improvement method. Under the premise of not changing the original installation size, the labyrinth path is changed from 3 to 2. Flange and groove are designed respectively at the end position of the dynamic seal. Meanwhile, the end face of the dynamic seal is extended to match the static labyrinth seal perfectly. (2) Improvement principle. The original labyrinth seal consists of three labyrinth paths. The static labyrinth seal on the end face of the labyrinth has a short eaves, and when the dynamic labyrinth seal is combined with it, the labyrinth path moves in a radial direction, which makes it easy for coal powder to enter the labyrinth path. After long-term operation, the labyrinth path becomes wider and coal powder enters more easily, resulting in the failure of the labyrinth. Under the premise of not changing the original installation size, the maze path is changed from 3 to 2. Flange and groove are designed at the end of the dynamic and dynamic seal. Meanwhile, the end face of the dynamic labyrinth seal is extended, and the eaves of the end face of the dynamic labyrinth seal are extended. A lip sealing installation space is added to eliminate the passage of coal powder into the maze, and the sealing performance of the maze seal is optimized.