The domestic air jet mill enterprises have faced many problems, such as the small scale of the enterprises and the low grade. However, in recent years, the air jet mill industry is constantly improving, so its competition has been increasing. It is mainly about the improvement of gas source, raw material supply and classification
The air source is the power of the air flow pulverizer in the crushing process. The requirement for compressed air can be between 0.7 and 0.8MPa, and the pressure can be stable. Even if there is a fluctuation, the frequency should not be too high, otherwise the product quality will be affected. Secondly, the gas quality shall be clean and dry. The compressed air shall be purified to remove the moisture, oil mist and dust in the gas, so that the crushed mineral materials will not be polluted. In particular, the crushing requirements for materials with high purity are higher. The raw material supply is to lift the raw materials into the raw material bin with a hoist, and then send the raw materials into the crushing chamber of the airflow crusher through the feeding valve. The speed of raw material conveyor is automatically controlled to keep the concentration of raw materials and air in the crushing chamber relatively stable. Two pairs of nozzles are symmetrically installed in the crushing chamber. When the compressed air passes through the nozzle, it forms supersonic airflow to carry the raw materials to accelerate, collide with each other in space, and crush the raw materials into ultra-fine powder. The crushing effect is related to the shape and distance of the nozzle inner diameter, symmetry, and the mixing concentration of raw materials and air. The shape of the nozzle inner diameter determines the good speed and distance for the formation of sonic velocity, determines whether the acceleration distance and speed of raw materials are ideal, and the mixing concentration of raw materials and air also affects the particle size and output of products. The classification of air flow pulverizer is carried out by high-speed rotating classification wheel. The grading wheel looks like a circle“ Iron bucket” The center of the bottom is fixed on the main shaft of the directly connected motor, which is driven by the motor to rotate at a high speed. The opening is opposite to the pipe inlet of the micro powder collection system, and a certain gap should not be too large. Otherwise, the unselected coarse powder enters the pipe of the micro powder collection system from the gap, affecting the product quality. In order to prevent such events, the gap should be air sealed. The edge of the grading wheel is equipped with blades, and the gap between the blades is the channel for separating fine powder. The crushed fine powder floats with the air flow, and the ultrafine powder enters the fine powder collector through the gap between the blades due to its small particle size. The larger particles, under the centrifugal force of the grading wheel, splash to the outer wall and fall down for re crushing. By adjusting the rotating speed of the grading wheel, products with different particle sizes can be obtained.
