The fluidized bed airflow ultrafine airflow pulverizer in the dry pulverizer has a simple structure and can realize continuous feeding and discharging. It neither makes the material too thin nor too rough. Only materials with qualified particle size can be continuously transported out in time, and the particle size distribution is steep and straight. In addition, due to the crushing principle of this machine, supersonic high-speed airflow is generated through specially designed nozzles. Under the acceleration of the supersonic airflow, the crushed materials collide, squeeze, and friction instantly at the intersection of the nozzles. Since the internal parts such as the material and the wall will not produce strong impact, the equipment is durable and more importantly, the high purity of the crushed material is ensured. Another important feature is that the gas ejected from the nozzle forms adiabatic expansion in the crushing chamber, and the temperature of the material will not rise during the crushing process. On the contrary, the material is broken immediately at low temperature. In this way, without adding refrigerant, the physical and chemical properties of the heat-sensitive material can be kept unchanged.

However, the energy consumption per unit output of the fluidized bed airflow ultrafine airflow pulverizer is relatively high. Although this crusher has many advantages, it is still too heavy for products with low added value.

However, people still have great enthusiasm and expectations for fluidized bed jet mills. Some scholars believe that if the efficiency of the fluidized bed airflow ultrafine airflow pulverizer can be increased by 1-2 times, it will be a very meaningful thing. Due to the improvement of the working efficiency of this kind of coal pulverizer, a broader application prospect will be opened up. Many people are still working tirelessly for this.

For a long time, we have accumulated a certain amount of practical experience in the research, development and use of the fluidized bed airflow ultrafine jet mill.

In order to improve the working efficiency of the ultrafine coal mill, two aspects must be considered first, namely the coal mill itself and its control conditions.

Summarized as follows:

(1) Strictly control the feeding speed: the feeding speed should be appropriate and uniform. In addition, you also need to consider what kind of feeding method to use. Some materials need to use a screw feeder, and some materials need to use oscillating feeding. The cutting method depends on the characteristics of the material itself. The most important thing is to ensure that the energy in the crushing chamber is continuously supplied with materials to meet a certain concentration of materials in the crushing chamber. Practice has proved that whether the material concentration is too low or too high, it will have an adverse effect on the output of finished products. Low material concentration will reduce the probability of contact between materials, and high material concentration will affect the airflow speed. Both are not conducive to the improvement of efficiency. The feed rate of the material should be strictly controlled according to the air pressure, material characteristics and the characteristics of the body itself.

(2) Increase the air velocity and particle collision probability. This should be agreed in two ways. First of all, the design of the nozzle should be reasonable, and the layout of the nozzle is also very important. Only by meeting the above two requirements can the goal of improving production efficiency be achieved.

In the traditional fluidized bed airflow ultrafine airflow pulverizer, the nozzles are arranged in parallel around the pulverizing chamber, and the airflow from the nozzles is concentrated in an approximate plane range, and the crushing area is narrow, which is not conducive to improving the probability of particle impact. In addition, the shortcomings of this design are also reflected in the coarse powder under the nozzle, which rarely has the opportunity to be crushed again to form a blind zone.

The ultra-fine jet mill breaks the traditional nozzle setting mode. In the same plane of the crushing chamber, at a certain angle to the plane, several nozzles are arranged symmetrically downwards. In addition, the bottom end of the crushing chamber is provided with a vertical upward nozzle, which points to the same focal point together with the center lines of other nozzles. Under the combined action of the airflow from all nozzles, the material forms a cone and gathers at the focal point, and the material is instantly crushed. In addition, a mixing tube is installed in front of the nozzle, so that there is no blind zone in the crushing chamber, which increases the probability of particle impact. Only this modification can increase the efficiency by 150-200%.

(3) Optimize the hierarchical structure. Classification is an important part of the superfine grinding system. One of the most notable features of the fluidized bed airflow ultrafine airflow crusher is that it can realize continuous feeding and discharging, preventing the material from being too fine and broken, causing unnecessary energy consumption. According to the principle of turbine classification, appropriately increasing the diameter of the classifier runner, increasing the speed, and reducing the air volume are the fundamental guarantees to ensure the separation of fine particles in the classifier. According to the characteristics and specific requirements of different materials, control the relationship between the above three.

(4) The raw materials entering the ultrafine jet mill should be as small as possible. In order to achieve this goal, an ordinary pulverizer should be used before superfine pulverization. This is the most direct and effective way to save energy and increase unit output.

(5) Ensure that the airtightness requirements of the entire closed system of the fluidized bed airflow ultrafine airflow pulverizer, including the fully enclosed devices of pipes, valves and equipment, should not leak. In short, valuable pneumatic energy must be concentrated on the nozzle, and efforts to increase gas flow and pressure.

(6) The product dust collector should ensure smooth air supply without excessive resistance. This part of the system must not only ensure the collection of qualified products, but also ensure that the environmental requirements and are not polluted. However, if the equipment is too large and complicated, it will bring too much burden to the whole work.