When mineral sizers are used in the open pits in the cold area, it is common to see the broken material sticking to the roller, especially in winter. The material makes the rollers sticky, the tooth tip can not be exposed, so that the tooth roller can not complete the hammer operation, becoming the smooth roller, the material can not be broken. So that the upper conveying mechanism material accumulation, it can only stop for cleaning. Cleaning labor is intensity and waste time, greatly affect the work efficiency. The phenomenon of parking cleaning should be carried out several times a day, so that the production task can not be completed.
2. Reason analysis of material bonding:
(1) The raw coal produced in open-pit coal mines is mainly lignite, but the raw coal produced by our company has a bedding shape, and the particle size of 500-1000mm is more than 30%. Due to the laminated layer, there is a laminated layer.
(2) Due to the restriction of surrounding hydrogeological conditions, the surface and groundwater are developed, which increases the water content in coal.
(3) The reasons of mining technology and temperature.
In winter, the coal mining operation is carried out with the electric shovel. The thickness of the coal seam is 6-7m and the mining height is full at one time. In winter, the thickness of the frozen layer is 1.7-2m, and the temperature of the coal within the frozen layer is 0-5℃, which is called "warm coal". While the crusher is used in the open air, the temperature of the working tooth roller is the same as that of the outdoor temperature, which is generally -25C--30℃. In this way, the temperature between the material and the working device is very large, resulting in the phenomenon of frozen sticking.
(4) The distance between the two teeth rollers is small, and the tooth density is too large.
To sum up, grinding, water content, mining and temperature and tooth density, each is an inevitable condition for material bonding.

3.Improvement of mineral sizers
(1) Using the mineral sizers original crusher frame, a cleaning mechanism was installed between the two roller teeth. The result was unsuccessful. The reason is that the moment of inertia of the tooth roll is very large, the coal is hard among the teeth, and there is no corresponding material and structure to deal with it, so that the cleaning mechanism or the frame is damaged.
(2) After repeated thinking and research, the final decision is made to improve the structure of the gear roller gear ring. The guiding idea of improvement is: the original 2-tooth roller teeth are too dense is one of the reasons for easy bonding materials. The structure of the original machine is that each roller has 3 columns of circular gear rings, each column gear rings have 15 rows of teeth in the axial direction and 24 teeth in the circumferential direction, and there is a gap at the top of the teeth between 2 rollers. The relative position between the first two roller teeth is shown in Figure 1.
(3) according to the original structure, two teeth roll has a relative circular motion, strength, structure of the improved roller tooth shape size, number of teeth, make no space between the 2 teeth roll tooth, but mutually meshing certain depth, in guarantee under the condition of discharging granularity, using the meshing with each other using each other's teeth cleaned. (4) After the big improvement of the tooth roller, the size of the tooth roller will inevitably change, and the size of the frame, transmission device, housing and other components will change accordingly.
(5) According to the center distance of the 2 tooth roller and the other tooth roller as an active roller, can be adjusted, and the gap between the roller and the shell size calculation, the outer diameter of the tooth roller increased to 1240mm.
(6) The meshing depth between the two rollers was determined to be 100mm, and the tooth height was calculated to be 140mm according to the outer diameter of the rollers and the thickness and strength requirements of the eight edges inside the rollers and the tooth roots.
(7) The tooth plateau is 1130mm and densely covered. Now the tooth height is increased to 140fnlTl, and the force strength of single tooth is increased, so the tooth profile section needs to be increased. The calculated tooth profile section is 65mm? 5mm, and in the direction of tooth movement and tooth root for arc transition, reduce stress.
(8) the arrangement of teeth in the ring: because the tooth height is increased, the ring amplitude is changed, so the reinforcement is added in the circumferential direction of the teeth. According to the requirement of discharge particle size less than 150IlLrn and the section size of tooth shape, through calculation design, there are 6 rows of teeth in the axial direction, 6 rows of rings in the axial average part, and 18 teeth in the circumferential direction.
(9) After the improvement of the gear ring, the outer diameter size is increased to 1240mm, the meshing between the two rollers is reduced to 100, the tooth height is 140mm, the center distance between the teeth rollers changes to 1140mm, the original center distance is 1200mm, the center distance is reduced by 60mm, and the transmission mechanism tooth interaction appears. Therefore, the transmission teeth should be improved, and the movable passive transmission long gear should be improved separately to reduce its outer diameter by 120mm and the number of teeth by 3. Due to the reduction of the number of teeth, the revolution of the two tooth rollers changes, and the rotating speed of the active roller increases, resulting in the relative motion of the two rollers in the circumferential direction, which further improves the cleaning function. After this improvement, only the original design of the machine gear ring and movable transmission gear 2 items were improved to achieve the purpose.
4 Conclusion The different properties of the material, the region and the climate conditions will have an impact on the work of the crusher, so all aspects should be considered in the design. Through the analysis of the bonding reason of mineral sizers, the bonding reason was found out and an improved method was obtained. This method can also be used with other mineral sizers.

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