|There are a variety of classification methods of universal mill, or in the form of the structure or by crushing method, or by moving speed, or by force, or by the degree of refinement to divide.
Crushing ratio refers to the size change before and after the grinding particle size. For a single universal grinder, than the maximum size of which is equal to the maximum size of feeding and discharging; for pulverizing system consists of a plurality of universal mill, it is equal to the initial particle size and the final discharging granularity than, or equal to the single universal mill grinding ratio of the product. When using the crusher crushing material, crushing ratio is usually referred to as the crushing ratio.
When the grinding ratio is large, crushing operations tend to be accomplished in pulverizing system composed of several universal mill. The material in this system through the universal grinder, the particle size decreased gradually, and finally to achieve the required size. In the grinding system, each stage should choose appropriate and universal mill grinding ratio, maintain mutual cooperation between the various stages of production capacity at. At the same time, in order to reduce the excessive grinding in order to improve the grinding efficiency and reduce energy consumption, but also for screening or grading after each grinding operations.
The large grinding working energy consumption greatly the industry and agriculture production, but in the grinding operation, input universal grinder in the vast majority of the energy is converted into heat and absorbed by the universal grinder, air circulation and crushed material, directly used for crushing material found on the small amount: in the crushing machine, generally not more than 10%; in the grinding machine, is often less than 1%. Therefore, in order to reduce energy consumption, it must choose the universal grinder, appropriate uses method of operation, correct regulations best crushing ratio and output in unit time.
With general cement factory as an example, broken power machinery accounted for the total consumption of 10%, while the power consumption of the grinding machine is about 60%. Therefore, in the process of crushing must take to reduce excessive grinding measures, in order to achieve the purpose of energy saving.
The relationship between energy consumption and fine crushing degree
Comminution theory is mainly research on the relationship between energy consumption and crushed between refinement process. Because of comminution is associated with many factors is extremely complex process, so there is no accepted in the crushing theory unified conclusion, while only three important hypotheses, respectively:
The German Ritter Lingor in 1867 area hypothesis, that of solid material crushing, energy consumption and newly produced is proportional to the surface area; volume hypothesis proposed German kirke in 1885, that will shape similar material crushing into geometry similar products, energy consumption and the broken pieces into the volume or weight the United States is proportional; crack hypothesis of Bond and Wang Rendong of China in 1952.
The three hypothesis has its limitations in practical, area hypothesis is suitable for discharging size is 0.01 ～ grinding of 1 mm, size hypothesis is suitable for discharging size greater than 10 mm thick pieces and the pieces work, while fracture hypothesis is somewhere in between, apply from the pieces to coarse grinding is widely used within the scope of.