The technical and economic indicators of the screening process are screening efficiency and productivity. The former is the quality index, the latter is the number of indicators. There is a certain relationship between them, but also with many other factors, these factors determine the screening results. Factors that affect the screening process can be divided into three categories:
First, the physical nature of the being screened material
Including the material itself particle size composition, humidity, clay content and particle shape.
When the fine material particles content is large, the sieve productivity is also large. When the humidity of the material is larger, the screening efficiency will generally be reduced. However, the larger the size of the sieve, the smaller the impact of moisture, so for moisture-containing larger wet materials, in order to improve the screening process, generally you can increase the sieve approach, or use wet screening. Material containing mud large(when the mud content is greater than 8%) should be used wet screening, or pre-washing.
Second, the nature of the screen surface and the impact of structural parameters
Vibrating screen is to make particles and screen for vertical movement, so it is high screening efficiency, big production capacity. The relative movement of particles and screen surface is mainly parallel movement of bar screen, flat shaker, cylinder screen, the screening efficiency and productivity are low.
For a given material, screen productivity and screen efficiency depend on the mesh size. Productivity depends on the screen width, screen is wide and it is high productivity. Screening efficiency depends on the screen surface length, screen surface is long and the screening efficiency is high. The general aspect ratio is 2.
The greater the effective screen area (ie, the ratio of the screen area to the entire screen area), the higher the unit area productivity and screen efficiency of the screen surface.
The larger the sieve size, the greater the productivity of the unit screen surface, the higher the screening efficiency.
Third, the impact of production conditions
When the sieve load is large, screening efficiency is low. To a great extent the rate of sieve capacity depends on the size of the sieve and the total screening efficiency; the larger the sieve size, the lower the screening efficiency required, the higher the productivity.
Feed uniformity is great significance to the screening process.
The inclination of the sieve should be appropriate, generally determined by the test. And then the amplitude and vibration of the sieve, which is related to the structural properties of the sieve, in a certain range, increase the vibration can improve the screening index.