Theoretical hypothesis one
The crushed materials are affected by their own gravity or external force. After entering the crusher from the feed port, they are distributed in the radial direction and obtain centrifugal power under the action of the high-speed rotating centrifugal disk. After leaving the disk, they fly to the ring gear plate at high speed. In this way, the material and the ring gear plate, the material and the material continue to collide and rub each other, and the material is continuously crushed until it reaches a certain fineness, and finally is discharged out of the crusher through the screen plate to become the desired product. .
Theoretical Hypothesis Two
Crushing methods There are five main methods for mechanically crushing solid materials, namely, extrusion, bending, splitting, grinding and impacting. The first four use static force, and the last one uses kinetic energy. In most crushing machines, materials are often crushed under the combined action of two or more crushing methods, such as crushing machines. In the gyratory crusher, the main applications are extrusion, splitting and bending; in the ball mill, the main application is impact. And grinding. The crushing method is selected according to the physical properties of the material, the size of the material block and the required degree of refinement. For hard materials, extrusion, bending and splitting should be used; for brittle materials, impact and splitting should be used; for larger blocks, splitting and bending should be used; smaller blocks or small discharge particle size requirements, Impact and grinding should be used. If the crushing method is not selected properly, it will be difficult to crush or excessive crushing, both of which will increase the energy consumption in the crushing process.
Theory Hypothesis Three
Energy consumption and crushing theory. The large amount of crushing work in industrial and agricultural production consumes a lot of energy. However, in crushing operations, most of the energy input into the crushing machine is converted into heat and the crushing machine, circulating air and crushed The amount absorbed by the materials directly used for material crushing is very small: in crushing machinery, generally no more than 10%; in grinding machinery, it is often less than 1%. Therefore, in order to reduce energy consumption, it is necessary to select appropriate crushing machinery, adopt correct operation methods, specify the best crushing ratio and output per unit time. Under normal working conditions, the energy consumption levels of different refinement ranges are roughly as follows: ①Break to 100 mm 3～4 kWh/ton; ②Crush to 100～10 mm 5～6 kWh/ton; ③Crush to 10 ～0.125mm 20～30 kWh/ton; ④Crush to 0.125mm 100～1000 kWh/ton. Taking a general cement plant as an example, the power consumption of crushing machinery accounts for about 10% of the total power consumption of the whole plant, while the power consumption of its grinding machinery accounts for about 60%. Therefore, measures must be taken to reduce excessive crushing in the crushing process in order to achieve the purpose of energy saving.
The pulverization theory is mainly to study the relationship between energy consumption and the degree of refinement in the pulverization process. Since the crushing operation is an extremely complex process involving many factors, there is no universally recognized unified conclusion in the crushing theory, but there are only three more important hypotheses. They are: the area hypothesis put forward by German Ritterlinger in 1867, which believed that when solid materials were crushed, the energy consumption was proportional to the newly generated surface area; the volume hypothesis put forward by German Kick in 1885, believed that the geometric shape When similar materials of the same kind are broken into products with similar geometric shapes, the energy consumption is proportional to the volume or weight of the broken pieces; the crack hypothesis proposed by Bond of the United States and Wang Rendong of China in 1952.
These three hypotheses have their limitations in practice. The area hypothesis is more suitable for grinding operations with a discharge particle size of 0.01 to 1 mm, and the volume hypothesis is more suitable for coarse and medium crushing operations with a discharge particle size of more than 10 mm. The crack hypothesis lies between the two, and it is suitable for a wide range of operations from medium crushing to coarse grinding.
