CN2088905U - Air classification device for fine powder materials - Google Patents

Abstract

The pneumatic classification device for fine powder materials is composed of a two-stage classifier, a fine particle product collector, and an induced draft fan connected in series with a hose. The classifier has a constriction at the material and primary air inlet on the upper side of the classifier, a small-diameter fine particle outlet on the top, and a secondary air belt forming device in the middle. The two-stage classifiers have the same structural form, except that the diameter of the second-stage classifier is smaller than that of the first-stage classifier. The induced draft fan is used as a power to form a negative pressure on the entire device. The device can obtain powder products of several microns and can make the recovery rate of fine products reach 80%. It is suitable for the field of ultrafine particle classification technology.

Description

The utility model belongs to the technical field of ultrafine particle classification.

In metallurgy, chemical industry, building materials, light industry, electronics and other industries and some other high-tech fields, fine-grained powder materials and fine-grained powder products are required. At present, there are various specifications and types of fine powder wind classifiers at home and abroad. Hefei Cement Industry Design Institute produces a powder classifier, which is said to be able to separate powders of -30 microns, -20 microns, and -10 microns. There is a rotary impeller on the upper part of the classifier to make the material rotate. Due to the limitation of mechanical movement speed, the speed cannot be very high, and the centrifugal force obtained by powder particles is very small. At the same time, there is no effective dispersing force on the fine-grained powder flocculation particles, so it is difficult for this type of wind classifier to separate products finer than 10 microns. Shenyang Beiling Machinery Factory produces a cp-1 supersonic superfine pulverizer and classifier unit. Rely on 7-10 kg/ ^cm2 compressed air flow to crush and send the material into the classifier. There is a rotating impeller on the upper part of the classifier. The average particle size of the divided fine-grained products is less than 10 microns. In addition to the disadvantage that the speed of the impeller cannot be too high, this classifier also involves the equipment and operation problems of oil and water removal with compressed air. Therefore, the current domestically produced wind classifiers cannot separate finer powder particles, and more than 80% of powders are smaller than 2 microns.

The purpose of this utility model is to provide a two-stage classifier, each classifier has a secondary upwind belt forming device, the primary air inlet is provided with a constriction and a small-diameter fine-grained product outlet pipe diameter, and the structure is simple. It is a classification device with convenient operation, low energy consumption, micron particle size classification and high recovery rate.

The purpose of this utility model is achieved in this way. It consists of four parts: a two-stage classifier with a secondary air belt forming device, a fine product collector, and an induced draft fan. The upper part of the classifier is cylindrical, the lower part is conical, and there is a secondary air belt forming device at the junction of the cylinder and the cone. There is a fine particle outlet pipe at the top, and the diameter of the fine particle outlet pipe is less than 1/5 of the diameter of the cylindrical part of the classifier. There are inlets for materials and primary air on the upper side, and there is a constriction at the inlet. The secondary air belt forming device is a closed chamber composed of a ring and the cylindrical wall of the classifier. Several rows of small holes are punched equidistantly along the cylindrical wall, and each row has several holes. There is an opening on the side of the ring connected to the air rotameter to control the volume of the secondary air. The bottom of the conical section is the outlet for the coarse-grained product. The fine particle outlet of the first classifier is connected to the constriction of the feed air pipe of the second classifier. The structure of the second-stage classifier is the same as that of the first-stage classifier, except that the diameter of the cylindrical part of the second-stage classifier is smaller than the diameter of the cylindrical part of the first-stage classifier. The fine particle outlet of the second stage classifier is connected to the upper left side inlet of the fine particle product collector. There is a filter inside the fine particle product collector, and the bottom is the fine particle product outlet. The outlet on the upper right side of the fine particle product collector is connected to the inlet of the induced fan, and the outlet of the induced fan is the outlet of pure air.

Figure 1 is a schematic diagram of the structure of the fine-grained powder material wind classifier.

Fig. 2 is a structural diagram of a secondary air forming device.

The induced draft fan is the driving force of the air flow of the machine, and the induced draft fan is connected in series with the fine particle product collector and the two-stage classifier. Start the induced draft fan 18 to form a negative pressure in the entire classification device, the material is sucked from the material of the first classifier and the primary air inlet 1, and is accelerated to the near-sonic speed by the first classifier constriction 2 and sprayed tangentially into the first classifier 3 Inside. Part of the fine material goes out from the fine particle outlet 4 of the first stage classifier along with the air flow. The agglomerates of large-grained materials and other fine-grained materials stay in the primary classifier 3 and rotate and fall along the inner wall of the cylinder. The diameter of the first-stage classifier fine particle outlet 4 is smaller than 1/5 of the diameter of the first-stage classifier 3, so that the coarse-grained material is injected at a high speed without being carried away by the air flow. The particles that rotate and fall in the first classifier 3 meet the secondary wind belt of the first classifier. The wind direction of the secondary wind belt is opposite to the primary wind direction, and the wind column blown by each small hole plays a shearing and dispersing effect on the falling pellets. The dispersed fine particles flow out from the fine particle outlet 4 of the first stage classifier along with the negative pressure airflow. The air rotameter 5 of the first-stage classifier controls the air volume of the air entering from the secondary air inlet 6 of the first-stage classifier, so as to adjust the size and quantity of the particles exiting from the fine particle outlet 4 of the first-stage classifier. What can pass through the secondary air belt is mainly coarse grains, and the coarse grains are discharged from the coarse grain product outlet 8. The fine-grained material passes through the constriction 9 of the second classifier from the fine material outlet 4 of the first classifier with the airflow, and is sprayed tangentially into the second classifier 10 at a speed higher than that at the constriction 2 of the first classifier Inside. After being sprayed in, some of the fine-grained materials are taken out by the airflow from the fine-grained outlet 11 of the second-stage classifier, and the remaining coarser particles and undispersed fine-grained aggregates are discharged in the second-stage classifier 10. Turn and fall. The diameter of the fine particle outlet 11 of the second classifier is less than 1/5 of the diameter of the second classifier 10, so that the coarse material is sprayed in at a high speed without being carried away by the air flow. The falling particles in the second-stage classifier 10 pass through the secondary air belt formed by the secondary air forming device 14 of the second-stage classifier. The extremely fine secondary air column blown out from the small hole is opposite to the direction of the primary air, which can shear and divide the falling particles and aggregates, making them redispersed. The dispersed fine particles come out from the fine particle outlet 11 of the second stage classifier along with the airflow and enter into the fine particle product collector 16 . The second-stage air rotameter 12 controls the air volume of the air entering from the second-stage secondary air inlet 13 , thereby adjusting the size and quantity of the particles exiting from the second-stage fine particle outlet 11 . The finer particles remaining in the second classifier 10 after passing through the second secondary air belt are discharged from the medium grain product outlet 15 at the bottom of the conical part at the bottom of the second classifier. After the fine grain product that enters fine grain product collector 16 li is collected, discharges from fine grain product outlet 17. The pure air that comes out from the upper right side outlet of fine grain product collector 16 is discharged from pure air outlet 19 through induced draft fan 18.

The advantages of the utility model are: 1. Simple structure, no moving parts in the classifier; 2. Convenient operation, no need to use compressed air; 3. Can obtain extremely fine powder products of several microns; High recovery rate; 5. Low energy consumption.

In an embodiment, the fine-grained kaolin powder is classified. The particle size of kaolin raw ore is all less than 43 microns, and the particles less than 2 microns account for 44.3%. The fine-grained product 1 was obtained after the first classification operation. After mixing the coarse-grained and medium-grained products, the second classification operation is carried out to obtain the fine-grained product 2. After mixing the coarse-grained and medium-grained products, the third classification operation is carried out to obtain the fine-grained product 3 and the medium-grained and coarse-grained products. The results of graded occupations are detailed in the attached table.

schedule

Product Name Yield (%) -2μ Content (%) -2μ Recovery (%) Whiteness

Fine grain product 1 26.58 82.40 49.44 78.1

Fine-grained products 2 11.29 83.10 21.19 78.2

Fine-grained products3 8.47 82.80 15.83 77.2

Medium grain product 19.44 18.90 8.29 73.3

Coarse-grained products 34.22 6.80 5.25 66.1

Raw mine 100.00 44.30 100.00 74.4

Description of drawings

figure 1

1 - material and primary air inlet

2 - The first stage classifier shrinks

3 - First stage classifier

4 - Fine particle outlet of the first stage classifier

5 - First stage air rotameter

6 - The first secondary air inlet

7 - The first stage secondary air forming device

8 - Export of Coarse Grain Products

9 - Necking of the second stage classifier

10 - Second stage classifier

11 - Fine grain outlet of the second stage classifier

12 - Second stage air rotameter

13 - Secondary secondary air inlet

14 - Second stage secondary air forming device

15 - Export of medium grain products

16 - Fine particle product collector

17 - Export of micro-granule products

18 - induced draft fan

19 - Pure air outlet

Attachment 2

1 - material and primary air inlet

2 - classifier necking

3 - Cylindrical part of classifier

4 - fine grain export

5 - Secondary air inlet

7 - The cavity of the secondary air belt forming device

8 - coarse grain export

20 - Classifier cone part

21 - Secondary air inlet hole

Figure 1 is the accompanying drawing of the abstract of the specification

Claims (3)

1, a kind of microfine powder material wind classification device is that cylindrical lower portion is that conical clasfficiator, microfine product gatherer, an air-introduced machine are formed, be it is characterized in that by two tops:

(1) inlet of wind and material is arranged in the cylindrical side on clasfficiator top;

There is a reducing porch of (2) wind and material;

(3) the particulate product outlet of a minor diameter is arranged at the top of clasfficiator;

(4) junction has a secondary wind band to form device between clasfficiator cylinder and cone, and there is a secondary wind inlet its side;

(5) before the overfiren air port of secondary wind band formation device an air robot flowmeter is housed, the size of control and regulation secondary air flow;

(6) air-introduced machine, microfine product gatherer, second level clasfficiator, first order clasfficiator are connected in series by flexible pipe, and the work of air-introduced machine makes whole grading plant form negative pressure.

2, by the described microfine powder material of claim 1 wind classification device, it is characterized in that the closed cavity that the cylindrical barrel by annulus and clasfficiator forms forms, along cylindrical barrel equidistant beat arrange more, every row has several apertures.

3, by the described microfine powder material of claim 1 wind classification device, it is characterized in that second level clasfficiator is identical with the version of first order clasfficiator, just diameter is less than the diameter of first order clasfficiator.

Images