Mineral sizers is one of the main equipment in the production process in basic industrial sectors such as raw materials, power and coal, used to break raw ore or materials of a certain size to the required size. According to the particle size of the material and the size of the product, the crushing process can be divided into coarse crushing, medium crushing and fine crushing, and the toothed roller crusher is more suitable for the coarse crushing and medium crushing of the material. In the design of mineral sizers in the past, when determining the tangential force of the tooth roller and the power consumption in the crushing process, the theoretical calculation was often replaced by empirical comparison or testing. Therefore, a relatively complete calculation idea was not formed. Therefore, it is necessary to summarize the method suitable for various industrial production according to different material characteristics. And can effectively guide the production practice of the mathematical theory. At present, the main fracture theories include: Area hypothesis, volume hypothesis and fracture hypothesis. The theory applicable to mineral sizers force analysis of coarse and medium coal crushing process is the volume hypothesis theory, that is, the power consumption required to break the material into small particles with similar geometric shapes is proportional to the volume or mass of the material to be broken, which is called the second crushing theory. 2 conditions for tangential force analysis of tooth roll in order to carry out tangential force analysis of tooth roll, the following conditions are determined:
(1) the maximum particle size material is regarded as a sphere.
(2) there is no rolling phenomenon after the maximum particle size material enters the crushing chamber. (3) the material is elastic or brittle material, and the crushing size is required to be coarse or medium, which is suitable for analysis with the second crushing theory.
The force analysis and derivation of the 3-tooth roller are shown in figure 1. F, is the tangential force of a single set of tooth rollers:. The tangential component of the tangential force of the tooth roll on the material: F; the radial component of the tangential force of the tooth roll on the material: N is the positive pressure of the material on another tooth roll: F. Is the friction force generated when the material is subjected to the positive pressure of another tooth roller: 8 is f, and f, the angle between the two forces: The angle between 02a and ab, 02 is the axis of the tooth roller, 0 is the center of the material; b is the angle between 02a and a0; 0 is the engagement angle between the tooth roll and the material: R is the radius of the tooth roll: L is the distance between the axis of the two-tooth roll:, is the radius of the material; h is the tooth height.
The site application proves that the crusher designed by this method is in good condition and no design problems have occurred. According to the formula, the force of different 0 angle lower tooth rollers is different, and the tangential force of tooth rollers is the largest at 0 angle of the largest grain size. Using computer programming calculation, the force under different 8 angles can be analyzed. Based on the second fracture theory, a complete analytical method is established in this paper, which provides a new way for the design of mineral sizers.