Jet mill is one of the more commonly used ultrafine grinding methods. It is widely used in ultra-fine or fine crushing of materials in non-metallic minerals, medicine, chemical industry, metallurgy and other industries. The product has the characteristics of fine particle size, narrow particle size distribution, smooth particle surface, regular particle size, high purity and high activity.

At present, the commonly used jet mills in the industry mainly include: flat jet mills, circulating tube jet mills, and opposite jet jet mills.

1. Flat jet mill

Flat jet mill, also known as disc jet mill, is a kind of jet mill that is widely used in early industrial applications.

working principle

The material is accelerated by the nozzle of the jet feeder through the feed port, and then introduced into the crushing cavity. Driven by the rotating air current, they collide, rub, and shear each other to be crushed; the fine powder is crushed. The air flow is pushed to the central outlet pipe of the crushing chamber, and slowly descends into the hopper in a spiral motion in the cyclone separator; the exhaust gas is discharged from the exhaust gas discharge pipe; the coarse particles are thrown to the peripheral wall of the crushing chamber under the centrifugal effect, and cyclically crushed.

2. Circulating tubular jet mill

Circulating tubular jet mill, also known as vertical annular jet mill, also has an internal grading function. It can be divided into equal circular cross-section and variable cross-section circulating tubular jet mill. The most used is the JOM series (also called O type) variable cross-section circulating tubular jet mill.

working principle

After the material particles are crushed at a high speed, the high-pressure air drives the particles to move along the pipeline. Since the pipeline is O-shaped, the radius of the inner and outer rings is different, and the material movement path and speed of the inner and outer layers are also different. The relative movement of the material particles in each layer causes friction, shear, collision and crushing. At the same time, due to the centrifugal force, the dense particle flow stratifies, the coarse particles are in the outer layer, and the fine particles gather in the inner layer, and then are discharged from the discharge port, and the coarse particles continue to be crushed.

3. Counter- jet jet mill

The counter-jet jet mill, also known as the reverse jet mill, is a device where materials collide in supersonic airflow to achieve ultra-fine pulverization.

working principle

The material enters from the hopper and is sprayed into the crushing chamber by the high-speed airflow of the feed nozzle. At the same time, the crushing nozzle sprays the coarse particles falling from the classification chamber into the crushing chamber, and the materials collide. After being crushed, it rises to the classification chamber with the airflow. In the classification chamber, the airflow forms a main swirl to classify the particles. Because the coarse powder is located on the periphery of the classification chamber, driven by the airflow, it returns to the crushing chamber for further crushing, and the fine powder is discharged out of the machine through the middle exhaust port for solid separation and product recovery.