How to improve the grinding efficiency of jet mill
In recent years, with the development of modern industry, ultra-fine and ultra-fine pulverization technology has received more and more attention, especially the quality of the pulverization effect of raw materials in the pharmaceutical and chemical industries directly affects the subsequent process. The jet mill is the best in the current ultrafine and ultrafine grinding equipment, especially the disc type (spiral) jet mill because of its simple structure, easy disassembly and assembly, and good grinding effect. It has won many pharmaceutical and chemical companies. Favored, it has become a typical equipment for grinding high-purity, low-fineness products.
Airflow grinder requires a complete process system. How to maximize its function and reduce loss is also a crucial issue.
The compressed air after filtering and drying of the airflow grinder brings the animal material to rub against each other, so as to achieve the grinding effect; in the process of the disc airflow grinder, 80% of the electric power consumption is in the air source part of the compressed air. Making full use of compressed air is actually saving electricity to the greatest extent. How to scientifically adjust the jet mill to run under ideal conditions to improve the efficiency of the jet mill is the concern of many user manufacturers.
- Adjustment of feeding speed
The feeding speed determines the time for the materials to collide and grind in the grinding chamber. The feed speed is slow, the material stays in the grinding cavity for a long time, the number of particle cycles is large, and the grinding degree is more sufficient, so the grinding fineness is smaller; but too slow, the number of particles in the grinding cavity is too small, resulting in fewer collisions , Thus failing to achieve the desired effect. If the feed is too fast, there will be too much material in the grinding chamber, and the grinding fineness will be more effective.
Experiments have proved that uniform and stable feeding can ensure the stability of the swirling flow field in the grinding cavity. Adjust the feeding speed to make the gas-solid ratio in the grinding cavity reach the ideal state, so that the material particles can get the maximum and effective collision times, thereby increasing the grinding machine s efficiency.
- Change the speed of the grading ring or the grading wheel
The grading ring of the disc jet mill is equipped with grading. It is not as convenient and simple to adjust as the fluidized bed (classified) jet mill. Different materials have different properties, and the same working conditions have different smashing effects. It does not reach agreement, and requires a lot of experimental experience to get it.
Due to the rotation of the grading wheel, the internal swirling flow field in the crushing chamber is stabilized, so that the material is fully crushed, and the coarser materials can never pass through the grading wheel and can only return to the crushing chamber to continue crushing. Under the action of high-speed airflow, a large pulverization efficiency is achieved, and the fluidized bed jet mill also has certain advantages.
- Reasonable design of grinding nozzle
The shape of the nozzle is the key to reducing the energy loss at the nozzle. The compressed air passing through nozzles of different shapes will produce airflows of different speeds. Improper nozzle design and processing will directly lead to the failure of the speed of the pulverizing airflow or the more serious nozzle wear. The worn nozzle will deflect the airflow, causing part of the airflow to do work ineffectively and affect the pulverization efficiency.
- Other factors
In addition, there are other factors that should not be underestimated. For example, the hardness of the material to be ground is too hard, and the grinding cavity of the grinder is more severely worn. At this time, we need to replace the ultra-hard lining, such as ceramic corundum, which greatly reduces The abrasion of small materials to the grinding chamber and improve the purity of the collected materials.
In addition, in the pharmaceutical and chemical industries, materials that are easy to stick to walls such as moisture absorption and static electricity are often exposed. The materials adhere to the grinding cavity, discharge port, and receiver, which affects the progress of the entire process. Then you need to replace the special anti-sticking lining in the crushing chamber, spraying or lining the anti-sticking coating and lining in the receiver; reduce the length of the pipeline and the contact area of materials as much as possible, and improve the collection rate of materials. Effective antistatic equipment is also needed to treat materials containing static electricity.
After careful adjustment and maintenance, tap the potential of the jet mill, and use the machine more efficiently under the condition of ensuring the particle size index, which is of great significance for saving energy and reducing costs.