In the process of stone screening, the phenomenon of material blocking the screen often occurs, especially when the mesh is small, the blocking phenomenon is more obvious and common. Due to the diversity of stone shapes and the complexity of the existing environment, the reasons for hole blocking are also various.
1. The stone contains a large number of stone particles at the critical separation point. That is to say, the particle size of the crushed stone is critical with the mesh size of the screen. During the screening process of the stone, such particles are stuck in the mesh and cannot be sieved smoothly, resulting in blockage, which is called critical blockage.
2. There are many flaky materials in the stone. Due to the crushing or the stone itself, there are many flakes in the stone, and the flakes themselves cannot be sifted smoothly in the screening. At the same time, the flakes are intertwined into industrial wire screens, which hinders the screening of other materials and causes hole blocking.
3. There is a lot of mud in the stone. For example, the skin of the quarry is thick, and the mud of the skin is relatively sticky and mixed in the stone.
4. The water content in the stone is high. Since the stone contains a lot of mud or the stone needs to be washed with water, due to the intervention of water, the fine-grained stones are bonded to each other into a group on the one hand. On the other hand, the soil sticks to the screen surface, making it difficult for the material to be screened, causing the industrial screen to block holes.
Except for the first point, which can be slightly improved by increasing the amplitude of the polyurethane vibrating screen, the other points, the screen mesh with the traditional fixed mesh can not effectively solve the hole blocking phenomenon.
Although increasing the amplitude will improve the critical hole blocking phenomenon, it may also affect the service life of the screen machine.
In order to effectively solve the above-mentioned hole blocking problem, we adopt the form of changing the mesh structure to achieve the effect of preventing the screen mesh from blocking the hole.
1. Square grid
The square grid deforms the mesh on the premise of meeting the requirements of the screening process, and adopts a certain proportion of rectangular holes.
However, the direction of the mesh holes is different, which will affect the screening accuracy and the service life of the square mesh screen to a certain extent.
When the screen is sieved, the flakes in the stone are easily screened out. Therefore, this kind of screen can only be used for the screening of materials that are not seriously blocked and that there are basically no flakes in the stone.
2. Diamond anti-blocking screen
It adopts diamond-shaped hole anti-blocking screen, which is woven with two adjacent same screen bars with tiny vibrations. It has better anti-clogging effect.
3. Triangular anti-blocking screen
The feature of the triangular hole anti-blocking industrial screen is that among the two adjacent screen bars, one is a static screen bar and the other is a moving screen bar.
Its basic principle is to expand the plane two-dimensional fixed holes to the three-dimensional three-dimensional variable mesh holes, and use the secondary vibration generated by the adjacent screen bars in the random vibration to establish an effective vibration difference.
The continuous change of the sieve hole in the screening is realized, and there is relatively no fixed critical particle stone. The specific method is to set a moving screen bar with a relatively large vibration amplitude in two relatively stationary static screen bars. The moving screen bars bounce or sieve the stone during jams.
According to the characteristics of the stone, the relative elastic strength and vibration amplitude of the static and dynamic screen bars can be adjusted accordingly, so that the industrial woven wire mesh can be in the best screening state.
The screening efficiency can be increased by about 30% compared with the fixed mesh screen, which basically realizes the self-cleaning function of the screen and greatly reduces the blockage of the screen holes.
The static screen bar of the screen is thicker than the moving screen bar, so it not only increases the wear resistance of the screen, but also improves the screening efficiency. At the same time, the screen structure of the screen can minimize the contact point between the stone and the screen hole, and reduce the occurrence of hole blocking.
4. Corrugated anti-blocking screen
The anti-blocking principle of the corrugated anti-blocking industrial screen is to use the vibration difference generated between the two screen bars to play the anti-blocking effect.
If there are stone particles embedded between the two sieve bars, the vibration of the upper and lower dislocation of the two sieve bars is poor, so that the particles stuck in the middle can pass through smoothly, which has the effect of preventing hole blocking.