Industry Reports

The impact of particle size on the vertical mill system

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  • Dec 19, 2019  UTC+8
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  • Tags: vertical mill system vertical roller mill

The vertical mill allows a larger particle size, but the impact of too much material intensity is different from that of a ball mill. In general, the change of the particle size of a ball mill only affects the output of the vertical roller mill and Out of the fineness of the impact. If the grinding force is large, the output of the ball mill will be reduced, and the fineness of the product will increase. However, for the vertical roller mill, the excessive grinding force will not only reduce the product quality, but also cause the mill's system failure more easily. Some enterprises have failed to control the intensity of the materials to be milled to the required range due to process conditions or management reasons. Especially in the past, the enterprises using the ball mill grinding system did not understand the importance of controlling the strength of the materials into the mill, which led to excessive materials entering the vertical mill, which caused a series of problems.

There are many types of vertical mills, but their working principles are basically the same. The grinding disc of the mill is driven by the main motor, and the grinding roller is pressed on the material layer of the grinding disc under the action of the hydraulic pressure. The friction roller causes the grinding roller to rotate on its own axis due to friction. After the material is pulverized by the combined action of extrusion and grinding between the grinding plate and the grinding roller, the centrifugal force of the grinding plate is thrown from the surroundings, and the hot air for drying is brought into the upper classifier by the air nozzle around the grinding plate for classification. The fine powder is taken away, and the fine powder is collected by a dust collector, and the coarse powder is ground back and ground.

One of the consequences caused by the too large amount of ground material is increased vibration, which causes serious wear of the liners of the grinding rollers and table, and causes uneven grooves, cracks and broken edges. Since some larger materials are not spheres, the clamp angle will change. Although some irregular large materials can be embedded by the grinding roller, due to its large particle size, the grinding roller will be slightly pushed up. After that, the grinding roller will fall back under the action of the hydraulic system. In this case, , The vibration of the grinding roller will be very obvious. As is known to all, excessive vibration will greatly increase the dynamic load of parts for mechanical systems. This shock dynamic load is very harmful to various parts and components, resulting in frequent aggravation of bad working conditions such as abrasion of the liners of grinding rollers and table.

Too large a material will also cause the vertical grinding scraper table to loosen and fall off. The fine materials thrown out by the grinding disc are blown up by the gas at the wind ring. The large particles that cannot be blown fall into the accumulation box and are scraped out by the scraper plate installed on the grinding disc. Due to the large particles of the incoming material, it is not easy to be Grind to the desired fineness, and more material falls into the accumulation box. Therefore, when the load starts, the resistance of the scraper is large, which makes the screws that fix the scraper loose, and in severe cases, the scraper falls off, resulting in a phenomenon of filling, which makes the main body of the vertical mill increase in load and jump.

The above is a part of the situation caused by too large a grinding material, which indicates that the large grinding size of the vertical mill affects not only the output and quality, but also the normal work of the vertical mill and the life of mechanical parts, which brings a system The applause has affected the work of vertical roller mill.

The manufacturers of vertical mills as well as the manufacturers should avoid the various impacts caused by too large materials to be milled to avoid problems in the production of vertical mills.