Wind grading equipment

Wind grading equipment has two types of gravity and centrifugal force, and some devices also have inertial force.
1. Gravity Wind Grading Apparatus Figure 1 shows several simple representative gravity wind classifiers. In the classification box shown in Fig. 1a, the raw material is fed from the upper feed hopper. Under the action of the horizontal air flow, the coarse grain falls close to the place, the fine particles fall far, and the fine particles which cannot be dropped are carried away by the air flow. By segmentation, a plurality of different fraction products can be obtained. This classifier is used to process thicker materials.
In the classifier shown in Fig. 1, the particles enter the classifier along with the airflow. Due to the sudden increase of the cross-flow section and the retardation of the baffle, the airflow speed is slowed down, and the coarse particles sink under the action of gravity and inertia, and the fine particles are Take the airflow away.
Figures 1a and e show a classifier that is carried out in an updraft. The former has two products; the latter one, the material is supplied from above, and the gas stream is supplied from the lower portion to obtain three products.

Figure 1 Gravity wind classifier

In the above-mentioned equipment, the fine-grained product carried away by the airflow, in addition to the other treatment methods, requires a dust collector to collect.
The updraft wind classifier (with cyclone dust collector) shown in Fig. 2 is in the same manner as a square grading chamber, and is provided with a plurality of vertically parallel "zigzag" guide plates 1. The material fed from the hopper to the sieve plate 2 is brought into the classification chamber under the action of the ascending air current supplied from the lower portion. During the process of bending the guide plate, the coarse ore particles are dropped and discharged together with the unscreened coarse particles. , as a coarse product. The fine ore particles are separated into the cyclone through the upper passage to obtain fine particles. The airflow from the upper part of the dust collector is returned to the fan, recycled, or drained from the hole 6.

Figure 2 Updraft Wind Classifier
1. guide plate; 2. sieve plate; 3. wind chamber; 4. adjustment grid; 5. cyclone dust collector;
6. Vent hole; 7. Fan; 8. Wind chamber; 9. Observation hole

2. Centrifugal force wind grading equipment The centrifugal classifier shown in Fig. 3 feeds the feed from the top to the rotary motion. Under the action of inertial centrifugal force, the coarse ore is thrown into the far-moving groove. Fine ore particles fall nearby, and medium grain size falls between the two.

Figure 3 centrifugal force wind classifier

Fig. 3 shows a centrifugal force classifier which carries a gas stream carrying ore particles and which is classified by inertial centrifugal force via a curved curved surface.
Another wind cyclone (Fig. 3) with a structure close to that of the hydrocyclone is used to increase the classification efficiency, and the lower part is also supplied with updraft.
Through the centrifugal classifier (see Figure 4), it is mainly used for closed circuit work with the dry mill. The equipment is mainly composed of the outer cone 1 and the inner cone 2. The upper part is provided with the guide vanes 5, so that the airflow from the inner and outer cones Cut into the inner cone in a tangential line. The mill product is fed upwards from the bottom pipe at a speed of approximately 18 to 20 m/s with the air flow. After entering the annular space between the inner and outer cones, the flow section is reduced and the speed is reduced to 4-6 m/s. Then, the coarse ore particles fall, are discharged from the tube 4, and are returned to the mill for re-grinding. The other ore particles are carried upward by the airflow, passing through the blade 5, and entering the inner cone through a tangential line to generate a swirling motion. Under the action of inertial centrifugal force, the coarser ore is thrown onto the inner cone wall, then falls, and is discharged by the discharge pipe 6. This product is either used as a product or returned to the mill, as the case may be. The fine ore particles are discharged from the top pipe with the gas flow and collected in the dust collector as fine grain products. [next]

Figure 4 through the centrifugal classifier 1. outer cone; 2. inner cone; 3, 7. pipeline; 4, 6. discharge pipe; 5. blade

The structure of the pass-through centrifugal classifier is relatively simple and easy to contact with the mill. The diameter is 0.3~3.65 meters, and the power of the fan is 1~92 kW. The productivity of the fine-grained product is related to the separation granularity, corresponding to tens of kilograms to 50 tons/hour.
The rotary impeller centrifugal wind classifier is widely used in industry. There are a variety of, the following is one of the more common one, called the double impeller centrifugal wind classifier, the structure is shown in Figure 5. The raw material is fed from the upper hopper 1, and falls on the turntable 2 which rotates at the bottom of the central shaft. Due to the centrifugal force, the particles are thrown to the wall of the inner cone 10, and the process is subjected to the upward flow caused by the rotating impeller. The ore particles reaching the wall are dropped by their own gravity and are discharged from the cone bottom discharge pipe 5 as a coarse product. The ore particles carried upward by the airflow enter the space between the inner and outer cones under the action of the upper impeller 3. Under the action of stronger centrifugal force, the particles are thrown to the cone wall, and are discharged from the discharge hole b after being dropped. , is a fine grain product. The air flow passes through the louver guide 7 into the inner cone and rises into a circulating air flow. By adjusting the sliding shutter on the throttle plate 8 by the hand wheel 9, the size of the upper passage can be changed and the updraft speed can be controlled. Increasing or decreasing the number of blades on the impeller can change the speed of the airflow rotation and the centrifugal force generated, thereby changing the separation granularity of the classification.

Figure 5 Double impeller centrifugal wind classifier
1. Feed hopper; 2. Turntable; 3. Lower impeller; 4. Upper impeller; 5. Crude product discharge pipe;
6. fine product discharge port; 7. louver guide; 8. throttle plate; 9. adjustment hand wheel;
10. inner cone; 11. outer cone

The classifier has a variety of diameters ranging from 1.2 to 5.5 meters. The impeller speed decreases with increasing diameter, corresponding to 400 to 165 rpm, and the motor is 7.5 to 93 kW. Treatment - 200 mesh accounts for 65% of the cement raw particles, and when -200 mesh accounts for 97% of the product, the treatment amount is 0.85 to 32 tons / hour.
The impeller type wind classifier has a compact structure, and it does not need to add a fan and dust collector, and the productivity is also large.
Cyclone dust collector is a kind of dust collecting equipment with a wide application, and it is equivalent to collecting dust and electric dust collecting equipment. However, in addition to being used for dust collection, the cyclone dust collector can also be used for dust removal (decentralized hydraulic dewatering) and classification. Therefore, some people call it a cyclone classifier, and some people call it a wind cyclone.
The structure of the cyclone dust collector is shown in Figure 6. Its structure and classification principle are basically the same as those of the hydrocyclone. Only the diameter is larger, the medium is air. [next]

Figure 6 cyclone dust collector
1. a cylinder portion; 2. a cone; 3. an intake pipe;
4. Upper cover; 5. Exhaust pipe; 6. Dust outlet

The cyclone dust collector has a diameter of about 0.15 to 3.6 meters, and the small diameter is assembled into a single device by a plurality of devices, or can be applied in parallel as a hydrocyclone. The feed of the dust collector is entered with the air flow. The speed of air flow entry is a very important factor, which is closely related to the separation granularity, classification efficiency and productivity. Table 1 lists the relationship between gas flow rate and separation particle size. The commonly used inlet wind speed is 12~20 m/s, and the dust collector of the appropriate specification should be selected according to the separation granularity. When the separation size is fine, a small diameter dust collector and a large wind speed should be used; otherwise, a large diameter dust collector and a small wind speed are used. The cyclone dust collector manufactured in China is shown in Tables 2 and 3.

Table 3 Technical Specifications of CLP/B Cyclone Dust Collector (2)

Gypsum Model Creative Point Drill

Gypsum Model Creative Point Drill,Gypsum Model Point Drill ,Craft Kits Kids Plaster,Coloring Toy Plaster Set

NINGBO JINCHEN CRAFTS GIFTS CO.LT , https://www.jinchenlovecrafts.com