Каква е разликата между струйна мелница с отворена{0}} и затворена{1}} мелница
2021-10-26
Jet mill is a micron-scale ultra-fine grinding equipment, which is relatively common in various powder industries. There are two different structures of jet mill, which are divided into open circuit and closed circuit. The open-circuit system usually refers to pulverizing with air as the medium, and filtering and discharging after pulverization. The closed-circuit system refers to the use of inert gas as the medium. The system is under the protection of inert gas during the whole process of feeding, crushing, grading, conveying, separating and packaging. After being dedusted and filtered, the inert gas is returned to the front-end system for recycling.
1. Introduction of open-circuit jet mill
Jet mill (fluidized bed jet mill) is a compressed air that is accelerated into a supersonic airflow through a Laval nozzle and then injected into the pulverizing zone to make the material fluidized (airflow expansion is a fluidized bed suspension boiling and collides with each other), Therefore each particle has the same motion state. In the crushing zone, the accelerated particles collide and crush each other at the intersection of the nozzles. The pulverized material is transported to the classification area by the upward air flow, and the fine powder that meets the particle size requirement is screened out by the horizontally arranged classification wheel, and the coarse powder that does not meet the particle size requirement is returned to the pulverizing area for further pulverization. The qualified fine powder enters the high-efficiency cyclone separator with the airflow to be collected, and the dust-laden gas is filtered and purified by the dust collector and then discharged into the atmosphere.
jet mill
2. Introduction of closed-circuit jet mill
The closed-circuit jet pulverizer generally refers to connecting the air outlet of the pulse dust collector with the air inlet of the air compressor that provides the power source for the system on the basis of the jet pulverizer to form a closed system, so that the pulverizing medium (air Or nitrogen, argon, helium, carbon dioxide and other inert gases) circulate in a closed system.
The closed-circuit jet pulverizer is a closed-circuit jet pulverization system developed for the pulverization requirements of flammable, explosive, oxidizable, volatile and other special materials using inert gas circulation protection. The working process is that the cooled inert gas is accelerated into a supersonic airflow through the Laval nozzle and injected into the center of the pulverizer. The pulverized materials enter the classification area with the upward airflow, and the powders that meet the particle size requirements are sorted by the horizontal turbine classification wheel in the classification area. The sorting of powder particle size is adjusted by the speed of the grading wheel. The sorted products are discharged from the centrifugal separator with the airflow or collected after being filtered by the dust collector. The unqualified products continue to return to the crushing area. crushed. The filtered inert gas is compressed and recycled by the compressor system, and the whole process is automated.
The open-circuit jet mill can be used for the processing of most common powder materials, while the closed-circuit jet mill is mainly used for flammable, explosive and oxidizable raw materials. Users can choose according to the raw materials and processing requirements.