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.
Tangential force analysis condition of tooth roller. In order to analyze the tangential force of the tooth roll, the following analysis 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. Force analysis and derivation of 3Mineral sizers tooth roller f. Tangential force of a single set of tooth rolls; . 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: W 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 meshing 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 rolls; , is the radius of the material; h is the tooth height. According to the setting of tangential force analysis condition (2) of tooth roll, the material does not roll after entering the crushing chamber, then: F. =fm=f·n, where: ∫ ∫ is the friction coefficient between the material and the side wall. F,=f·n·tg6. (4) under the action of two forces f, and n, the material decreases △ along the radius, then the work done by the two forces is: W=f,·△r+n·△r. (5) according to the second crushing theory, the power consumption required is proportional to the volume or weight of the material to be crushed,
This example is to design a mineral sizers for our customer in xinjiang. Known: R1=15cm; r=30cm; l = 70.5 cm; 0= 43°; h=8cm; 8=2×10°kg/m2; e=6.7 x 10kg/m2. Through calculation, the maximum tangential force of a single set of tooth rollers is obtained as follows: F,=926.28(kg)=9077.5(n). Since the arrangement of the crushing teeth of mineral sizers tooth roll is the same in two groups, the maximum tangential force may exist in two places at the same time in the whole tooth roll. Therefore, the total tangential force f is twice the force of a single set of teeth, that is: F,=2f,=18155(n)o from this, the torque can be calculated, and the required power can be calculated in combination with other influencing factors. The site application proves that the crusher designed by this method is in good condition and no design problems have occurred. (2) according to the formula, the force of different 0 angle lower tooth rolls is different, and the tangential force of tooth rolls is the largest under 8 angle of the largest grain size. Using computer programming calculation, the force under different 0 angles can be analyzed. (3) Based on the second fracture theory, a complete analytical method is established in this paper, which provides a new way of thinking for the design of mineral sizers.