What are the factors that affect the screening efficiency of vibrating screens?
Thickness of material layerThe use of plane screen, such as through the vibration sieve surface material layer is too thick, the upper layer material of small particles through the sieve, sieve will cause the error rate, which will increase in raw material cleaning net loss of raw materials, in the classification of particles will reduce the yield (in the upper sieve material layer is too thick, affect the quality of the finished product (lower) the sieving layer is too thick). When the material layer is too thin, the sieving output is too low and undesirable. The suitable material layer thickness should be determined by experiment. When the screen angle is small and the sieve amplitude is large, the material layer may be slightly thicker. Theoretically, the thickness of the material layer is determined by the output, but in actual use, the material may be concentrated on one side of the screen due to uneven feeding of the screen surface, resulting in the excessive thickness of the local material layer, thus affecting the screening effect. The cylindrical screen and the conical screen have similar problems, and when the material flow rate is too large at once, the sieving effect is also affected.
Screen opening rateThe greater the opening rate of the screen surface, the better the performance. If the screen strength is guaranteed, the woven sieve can obtain higher opening ratio than the punched screen, so the former is better than the latter.
Shape of grain and meshIn practice, most of the raw material is cylindrical Sieving (particle feed grade) or irregular particles, both circular and rectangular mesh, material particles contact state of the particles can pass through the mesh impact, through a hole diameter of 5 mm particles such as erect a 4 * 10 mm of the screen not horizontal. Therefore, whether or not particles pass by accident can only be studied by statistical means. Generally, the cylindrical particles and rectangular sieve holes have better performance, but for the irregular particles with small size difference in each direction, the passing performance of the circular hole is better.
Sieve motion stateOne of the necessary conditions for the screening process is the screening material and the relative motion between the appropriate screen surface, this method can generate relative motion is the screen surface horizontal reciprocating linear motion (rotation), vertical reciprocating motion (vibration) or a combination of the two. Sieve body only horizontal reciprocating movement or vertical reciprocating movement, screening effect is not ideal. The latter, due to the lack of materials and the relative movement of the screen surface, is likely to cause uneven thickness of the material layer. The practice shows that the rotary vibrating screen combined with two kinds of motion has better effect.
