The angle between the screen surface of the vibrating screen and the horizontal direction is called the installation slope of the vibrating screen. The installation slope of the vibrating screen is closely related to the screening efficiency. If the slope is too large, the time for materials to stay on the screen surface is short and it is easy to discharge. , but it may cause poor material screening. If the slope is too small, although the material stays on the screen surface for a long time, it will cause low output per unit time. So, what is the appropriate slope for the vibrating screen to be installed?
The vibration direction angle is the angle between the vibration direction line and the screen surface. The larger the value of this angle, the smaller the horizontal movement distance of the material during the screening process, and the lower the moving speed on the screen. Through practice, the screen For materials that are easy to sieve, the direction angle should be smaller, and for materials that are difficult to sieve, the direction angle should be larger. In general, the direction angle of the linear vibrating screen is between 30 degrees and 60 degrees, while the direction angle of the circular vibrating screen is 90 degrees. There are many factors that really affect the efficiency of mining vibrating screens, among which three more important factors are the characteristics of the materials entering the screen, the parameters of the vibrating screen surface, and the motion parameters of the vibrating screen.
1. The characteristics of the screened material
Different materials have unique characteristics, such as density, hardness, moisture content, etc. Generally speaking, the screening effect of materials with higher hardness and better brittleness is better than that of materials with lower hardness and poor brittleness. For sieving materials, there are two aspects that can directly affect the screening effect: material particle size and material moisture content.
When the particle size of the material is close to the size of the sieve hole, the screening efficiency will be significantly reduced. These particles may block the sieve hole, resulting in a decrease in the effective screening area. This is a phenomenon that often occurs in the closed-circuit crushing process. The amplitude of the sieve can be improved. The increase of the amplitude can promote the passage of fine-grained materials through the sieve surface and reduce the occurrence of clogging. In addition, it can also increase the passing rate of the middle part of the sieve, so that the screening effect can be improved. It can also be improved by changing the feeding method. To improve the utilization rate of the screen surface of the vibrating screen, multi-channel feeding can be used to reduce the movement time and distance of the materials on the screen on the screen surface and improve the screening effect.
When the water content of the material is high, the material is prone to sticking, which reduces the screening efficiency. Generally speaking, the wet material with high water content can improve the screening effect by increasing the sieve hole, but if the material contains mud When the amount is greater than 8%, it should be treated by wet screening or pre-washing.
2. Vibrating screen surface parameters
The parameters of the vibrating screen surface include the shape of the vibrating screen hole, the opening ratio of the vibrating screen surface, the material of the screen surface, etc. Generally speaking, the long screen surface has a long residence time of materials, more chances of passing through the screen, and high efficiency, while the wide screen surface has better processing capacity. Practice has proved that the appropriate ratio of screen surface aspect ratio is 2:1~3:1.
The opening ratio of the vibrating screen surface here refers to the effective screening area of the vibrating screen, which is the ratio of the screen hole area to the total area of the screen surface. The larger the effective screen hole area, the higher the productivity per unit screen surface, and the higher the screening efficiency. higher. As for the shape of the sieve hole, it is selected according to the particle shape of the material. Generally, it is better to use a square sieve hole to sieve materials with round particles.
In terms of materials, different screen surface materials will also have an impact on the screening effect, which can directly affect the adhesion coefficient between minerals and the screen. For viscous minerals, rubber and polyurethane screen materials with greater elasticity should be used. Ensure that the material on the sieve is loose. However, such materials usually have the disadvantage of relatively small open porosity.
3. Vibrating screen motion parameters
The motion parameters of the vibrating screen include two factors: the vibration frequency of the vibrating screen and the direction angle of the vibrating screen. Vibration enables the materials on the screen surface to be thrown away from the screen surface, so that the coarse-grained materials reach the upper layer of the material layer, and the fine-grained materials reach the lower layer of the material layer, close to the screen surface, the screen layer is evenly distributed, and the passing rate of fine-grained materials increases accordingly. For materials with large particle size, generally, the higher the frequency, the higher the number of beatings on the screen surface, the greater the chance of contact between the material and the screen surface, and reduce the occurrence of screen hole clogging. Therefore, appropriately increasing the vibration frequency can effectively improve the screening effect.
4. Daily use and maintenance
During the daily use of the equipment, the operating procedures must be strictly followed, and the maintenance and maintenance of the vibrating screen equipment should be carried out regularly to ensure that the equipment is in good working condition;
After understanding the factors that affect the efficiency of the vibrating screen, appropriate improvements can be made to improve the performance of the equipment, and the screening work can be carried out smoothly.
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