Summary:
Air flow classifier is a kind of air flow classification equipment. The classifier, cyclone separator, dust remover and induced draft fan form a set of classification system. Under the suction of the fan, the material moves to the classification area at high speed from the feed port at the lower end of the classifier along with the updraft. Under the strong centrifugal force generated by the high-speed rotating classification turbine, the coarse and fine materials are separated. The fine particles meeting the particle size requirements enter the rotary air separator or dust remover through the clearance of the classification wheel blades for collection. After the coarse particles with some fine particles collide with the wall, the speed disappears along the cylinder The wall descends to the secondary air outlet, through the strong washing effect of the secondary air, the coarse and fine particles are separated, the fine particles rise to the secondary classification of the classification area, and the coarse particles fall to the discharge port for discharge.
Working principle
The rotor impeller of the air classifier is a compound two-way centrifugal type. The impeller rotates at a high speed, forming a negative pressure area at the lower part of the impeller. The air in the classification cylinder enters through the air inlet at the lower part of the impeller, and is discharged from the outlet along the upper impeller passage, and flows out through the injection fine-grained ring. Under the action of the control ring, the air rotates upward, and there is a partial speed in the axial and circumferential directions, and the air flows inward through the upper space of the classification disk, It enters into the lower impeller through the upper inlet of the impeller and is discharged from the outlet of the lower impeller. The discharged air flows downward in the cylinder, and then flows upward through the middle of the inner cylinder to the lower inlet of the impeller, so as to form a cross circulation air flow. The material input from the star feeding valve falls into the high-speed rotating material rejection plate, which is thrown to the retaining ring under the action of centrifugal force, and under the action of the retaining ring, the material is dropped down into the grading cylinder. Under the action of cross air flow, the coarse particle material slides from the wall of the control ring to the coarse material collector, while the fine powder is transported to the lower fine powder cyclone collector (inner cylinder of the grading cylinder) along with the air flow of the air suction port in the upper middle part of the rotor, so that the raw material is divided into two parts: coarse and fine, while the remaining air is sucked in by the suction port in the lower middle part of the rotor, flows through the blades, the injection fine particle ring and the control ring, Then from the periphery of the control ring to the middle air intake above the rotor, forming a continuous automatic cycle. In order to ensure the air balance and stability in the classification room, the excess air brought in by the materials and the air expanded due to the high temperature of the classification room are discharged from the residual air outlet. The air outlet is equipped with a filter bag to prevent the discharged air from polluting the environment.
Performance characteristics
It is suitable for the fine classification of dry micron products. It can be used for the classification of spherical, flaky and irregular particles, as well as the classification of particles with different densities. The particle size of the graded products can reach d97:3-150 μ m, the particle size of the products can be adjusted steplessly, and the variety change is very convenient. The classification efficiency (extraction rate) is 60% - 90%. The classification efficiency is related to the properties of materials and the content of particles that meet the requirements of particle size. The fluidity of materials is good, the content of particles that meet the requirements of particle size is high, the efficiency is high, otherwise it is low. The speed of the grading wheel is high and the vertex cutting is accurate. It can be used in series with multi-level graders to produce products with multiple particle size segments at the same time. It can be used in series with ball mill, vibration mill, Raymond mill and other grinding equipment to form a closed cycle. The control system adopts program control, real-time display of running state and simple operation. The system operates under negative pressure, the dust emission is more than 40mg / m, and the noise of equipment operation is not higher than 75db (a) after the noise reduction measures are taken.