Cone crusher has become the development direction of crusher because of its simple structure, light body, high output, relatively stable work and easy to realize automatic control. The cone crusher has a good effect on crushing materials with medium hardness or above, and its compression ratio has a wide control range, good output and quality, uniform product particle size and low energy consumption.
There is also a disadvantage of early cone breaking, that is, the needle and flake content of the finished product is large and the particle shape is not good enough. However, after 1980, some scholars put forward the laminated crushing theory. Moreover, when introducing products to customers, many manufacturers often mention that their cone breaking products adopt the principle of laminated crushing, and the product particle shape is better. So, what is laminated crushing? What conditions need to be met to achieve laminated crushing? Fodamon engineer will explain to you as follows.
What is lamination crushing?
Materials squeeze and grind each other, and break at their cracks and defects. This process is called laminated crushing. Generally, in the field operation of the cone crusher, single particle crushing can be considered to occur only when the size of the material is large or the size of the crushing cavity is small enough to form an effective crushing layer, that is, single particle crushing can occur only for the materials at the feed port and discharge port. Materials and materials will certainly squeeze each other, and most of them are broken in this case, that is, materials are laminated and broken at other positions in the crushing chamber.
Laminated crushing theory refers to the extrusion crushing of materials in a multi-layer distribution in the crushing chamber. In the process of crushing, materials will not only be squeezed by the moving cone and the fixed cone, but also have extrusion collision between materials, which truly reflects the crushing condition of materials in the crushing chamber.
How to realize laminated crushing?
Of course, certain preconditions must be met in order to realize laminated crushing of materials:
(1) Sufficient feeding: because only sufficient feeding can form a certain number of material layers and realize the laminated crushing effect, and when the number of crushing layers is 6-10, the energy-saving effect will be obvious, which will also reflect the advantage of high laminated crushing output;
(2) Uniform feeding: uniform feeding will make the material stress distribution reasonable, and then make the crusher work smoothly;
(3) Uniform particle size: when the particle size and geometric size of materials vary greatly, small materials will protect large materials from being broken, that is, fine particle protection. Therefore, in order to avoid this phenomenon, the particle size of feed should be uniform;
(4) Filling degree: when the material filling rate is too small, powdery particles will appear, resulting in a certain waste, thus reducing the effect of lamination crushing; When the filling rate is too large, the material is too tight and easy to agglomerate, which is not conducive to the crushing. Therefore, a series of tests show that the filling rate between 0.55-0.75 is the most conducive to the laminated crushing.
How about the lamination crushing process?
According to the experimental research and analysis, the process of laminated crushing of materials can be divided into three stages:
(1) Compaction stage: at the beginning of the test, because the porosity between materials is very high and the pressure applied to materials is small, materials will not be squeezed and broken. With the action of pressure, the compactness between materials increases, so the volume becomes smaller and multiple reliable contact points will be formed;
(2) Crushing stage: due to the continuous compression of materials, the pressure on them will also increase. The denser the materials are, the lower the porosity is, and the greater the stress on the contact point. When these forces exceed the strength of a certain point of the materials, the materials will be broken. At this time, the sound of material breaking will be heard, and the swing of the pointer of the pressure plate will be seen, The reason for this phenomenon is that before crushing, the pressure value of the material will increase to a large extent. When it is crushed, the stress will decrease instantly and the material will be re compacted;
(3) Agglomeration stage: when the material is compressed to a certain extent by the press, the stress will increase rapidly, and the material will be compacted to produce a large amount of powder, resulting in agglomeration.
In the process of material crushing, the total electric energy consumed by grinding is almost four times that of crushing, but its production efficiency is far less than that of crusher. Therefore, in actual production, crusher should be used to replace crusher as much as possible, which is of great significance to reduce electric energy consumption. The materials crushed by the laminated crushing principle will be more uniform, the shape of the materials will be more cubic particles, and the content of materials with small particle size will be very high, so as to better match the theory of “more crushing and less grinding”.