Efficiency And Vibration Sieve Screen Surface Length

Screening equipment is widely used in the bulk was divided into two or more levels of granularity equipment. development and problems of the domestic large-scale screening equipment from the 1970s, the domestic in the development of large-scale screening machines, a lot of work, has made great achievements. screening machinery in the length and width of the screen surface …
Screening equipment is widely used in the bulk was divided into two or more levels of granularity equipment. development and problems of the domestic large-scale screening equipment from the 1970s, the domestic in the development of large-scale screening machines, a lot of work, has made great achievements. the length and width of the screen surface screening machine are two important structural parameters, it is the design and selection of screening machines when the first problem encountered. according to the theory of screening, the screen width and its related screening machine processing capacity, namely under the same conditions, the wider the screen surface, the greater processing power. screen surface length associated with screening efficiency, namely under the same conditions, appropriate longer sieve screening efficiency can be improved, however, by the probability screening mechanism we can see, with the screen surface is lengthened, particle size of the particles is greater than the separation through increased screening, while making the screening efficiency is reduced, the length of the screen surface can be seen there is an optimal value such that the maximum screening efficiency.
Was established on the basis of probability weibull model better reflects the particles along the longitudinal direction of the sieve through the sieve probability, probability screen is designed to provide a theoretical basis. on the basis of weibull model can be derived particles along the longitudinal direction of the sieve through the sieve efficiency formula, but the formula is too compli SBM ed, and there is no direct relationship between efficiency and screening function pointed a long, very inconvenient in the industrial appli SBM ion. experimental study of the screen surface length on the impact of screening efficiency is proposed based on the choice of screen surface length should consider the size of the particles of material composition, establish a quantitative relationship between the screen length and screening efficiency in the design and selection of probability on screen it can provide a more direct basis. this paper uses three dimensional discrete element method to simulate the probability of the screening process, the establishment of screening efficiency is a function of the length of the screen surface. numerical simulation
1 screening Portable Crusher efficiency with the screen surface length
With the continuous appli SBM ion of computer simulation in industry, discrete element method 20, 70 Crusher Machine developed world to deal with the particle system provides a new way. the method is based on the fundamental laws of particle collisions and newton’s laws of motion based on the motion of each particle in the system to track the process, resulting in the movement of the entire particle group. since the method parameters with little experience, you can easily set the particle size distribution and the desired properties, it has a wide range of adaptability. it based on the discrete element method of three-dimensional simulation of screening.
Screening of three-dimensional model (figure 1) consists of particles of plants, sieve box and sieve composition. particles plant can generate particle size or quality to
Subject with a certain distribution (normal, lognormal, etc.) particles, the initial velocity of the particles in the z-direction by gravity fall to the screen surface, set the screen surface vibration parameters (amplitude, vibration frequency and vibration direction angle), delamination and outflow through the sieve screen surface, such as screening effect, sieve box and sieve material can be collected under the screen and the screen surface under particle effects. simulations used by the material properties, the coefficient between the particles and the particles collide with the surface mesh sieve, particle motion friction coefficient be set too close to the practical engineering value. initial conditions detailed in table 1.
By the results of the simulation, along the x direction under subparagraph statistics sieve particles get different particle size sieve screening efficiency in the long direction. drawn from the data in table 2 versus the length of the screen surface between the screening efficiency, shown in figure 2, it can be seen from the figure, at the initial stage of the screen box, with increasing length of the screen, each particle size the screening efficiency is rapidly increasing, while relatively smaller particle size particles (0.2, 0.4) of its screening efficiency rapidly approaching the highest point. as long screen again increased screening efficiency of fine particles began a slow decline, while increasing the relative larger size of the particles have also slowed the screening efficiency. as can be seen from equation (1), with increasing length of the screen, a screen size of the particles which penetrate probability is increased, when the screen to infinite length, its probability is 100% transparent screen. single particle through the sieve probability theory suggests that a relatively small particle size of the particles and the screen surface contact through the sieve probability is great, so small particles can quickly sift through. the simulation of small particle size to achieve the highest screening efficiency in a shorter screen surface, which reflects the single particle through the sieve through probability theory is an approximation because the probability sieve screening equipment, provisions outside diameter of the particles screen, this will reduce the particle size of the screening efficiency. if a particle size of particles in the end not yet reached the screen surface completely through the sieve, the next screen will let through the sieve surface outside of this particle size, the screening efficiency secondary particle size is reduced. it can be inferred, the simulation screen long if it continues to increase, relatively large particle diameter (0.6, 0.8) screening efficiency will decline, only simulated by the computer hardware limitations, can not simulate a longer screening effect only.
3 conclusion: this article uses the discrete element method (dem) to simulate the probability sieve screening process proposed screening efficiency and relative size of the screen longer function formula. Sand Making Machine as can be seen from the function, the relationship between length and sieve screening efficiency of different particle sizes are different, the small size of the particles in a shorter screen surface can achieve maximum screening efficiency. the large particle size to achieve optimal screening efficiency requires a long screen long. therefore, in the design or selection of screening equipment, when the screen size is the composition of the material should be a factor to consider long sieve. after considering the impact of screening various parameters, plus function formula in this paper, it can make the design more perfect screening equipment.