A coarse-fine gradient grading powder separator and grading method and design method thereof

Abstract

The application discloses a coarse-fine gradient grading powder classifier and a grading method and design method thereof, and forms, from bottom to top, a wind distribution and material distribution area, a pre-scattering and coarse particle grading area, a feeding and medium-coarse powder return connection area, and a medium-coarse powder and fine powder grading area in sequence. The wind distribution and material distribution area comprises an air inlet shell, an air inlet, a coarse particle outlet, a flow guide cone and a ring-shaped air ring. The pre-scattering and coarse particle grading area comprises a coarse particle separation shell, a coarse particle separation rotating cage, a material distribution device and a coarse particle separation drive. The feeding and medium-coarse powder return connection area and the medium-coarse powder and fine powder grading area comprise a feeding pipe, a medium-coarse powder return pipe and a fine grading device. In addition to the separation function of the traditional dynamic selection, the application is also a combined device with the functions of scattering, material distribution and coarse-medium-fine particle separation, and can complete clearer coarse-fine particle gradient grading without using V selection, thereby solving a series of problems caused by the common problems of V selection and meeting the material separation requirements of a combined or semi-final grinding system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of powder selection, in particular to a coarse-fine gradient classification powder selection machine and a classification method and design method thereof. BACKGROUND

[0002] In the grinding process, since the roller press, vertical roller mill and other material bed extrusion equipment are more suitable for crushing large particles (d>0.2mm), it is difficult for fine materials to form a stable material bed, which causes equipment vibration, increases useless work, and results in high energy consumption. At the same time, water spraying for stabilizing the material bed also affects the quality of the finished product. The tube mill and stirring mill are more suitable for grinding small particles (d<0.2mm), and the coarse material is easy to cause the grinding efficiency to decrease and the large particles to run coarse, which cannot meet the fineness requirement of the finished product. Therefore, in the combined / semi-final grinding system composed of extrusion equipment and fine grinding equipment, the corresponding requirements for coarse-fine gradient classification are put forward.

[0003] In the traditional combined / semi-final grinding system, the material pre-ground by the roller press is separated by the V-type powder selection machine to bring the semi-finished product into the fine dynamic powder selection machine. Since the V-type powder selection machine relies entirely on the inertial force field to realize the classification of the semi-finished product, the separation process has poor controllability, and there is a common problem of local high wind speed caused by wind short circuit at the top of the V-type powder selection machine, which causes a large number of coarse particles to directly enter the fine dynamic powder selection machine. On the one hand, this leads to an increase in the concentration of the dynamic powder selection machine, and on the other hand, due to the entry of coarse particles, the speed of the powder selection machine must be increased under the same control condition of the finished product fineness, which in turn leads to a decrease in the efficiency of the powder selection machine, an increase in the circulating load, a decrease in the separation powder fineness, and more finished products returning to the roller press, resulting in unstable material layer, mill vibration, reduced grinding efficiency, and decreased hourly output and increased power consumption. At the same time, the return powder of the dynamic powder selection machine entering the tube mill also contains coarse particles (d>0.2mm) that should have entered the roller press, which causes an increase in the grinding load of the tube mill, an increase in the circulating load, a decrease in the powder selection efficiency and the grinding efficiency, and a decrease in the hourly output and an increase in the power consumption. SUMMARY

[0004] To solve the above-mentioned series of problems caused by the common problem of unclear V-type coarse and fine particle separation in the existing combined / semi-final grinding system, the application provides a coarse and fine gradient grading and powder separating machine and a grading method and design method thereof, which is a combined device with dispersing, distributing and coarse, medium and fine particle separation functions in addition to the coarse and fine powder separation function of the traditional dynamic powder separating machine, and sequentially comprises a wind distribution area, a pre-dispersing and coarse particle grading area, a feeding and medium-coarse powder return connection area and a medium-coarse and fine powder grading area from bottom to top. Unlike the V-type powder separating machine and the fine dynamic powder separating machine of the traditional combined / semi-final grinding system, the coarse and fine gradient grading and powder separating machine can complete clearer coarse and fine particle gradient grading without using the V-type powder separating machine, solve a series of problems caused by the common problem of V-type separation, return coarse particles (d>0.2mm) to the return bed extrusion equipment, select fine powder (d<0.045mm) as a finished product, return medium-coarse powder (0.045mm<d<0.2mm) to the fine grinding equipment, and meet the requirements of the combined / semi-final grinding system for different fineness materials.

[0005] The application is implemented as follows: a coarse and fine gradient grading and powder separating machine, which sequentially comprises a wind distribution area, a pre-dispersing and coarse particle grading area, a feeding and medium-coarse powder return connection area and a medium-coarse and fine powder grading area from bottom to top.

[0006] The wind distribution area comprises an air inlet shell, an air inlet, a coarse particle outlet, a guide cone and a ring-shaped air ring, the air inlet is located on the side of the air inlet shell, the coarse particle outlet is located at the bottom of the air inlet shell, the guide cone is coaxially arranged inside the air inlet shell, and the ring-shaped air ring is installed between the outer edge above the guide cone and the inner edge at the top of the air inlet shell.

[0007] The pre-dispersing and coarse particle grading area comprises a coarse particle separation shell, a coarse particle separation rotating cage, a distribution device and a coarse particle separation drive, the coarse particle separation rotating cage is located inside the coarse particle separation shell, the coarse particle separation rotating cage comprises coarse particle grading vanes located around, a cage frustum coaxially arranged inside the coarse particle grading vanes, and a dispersing round steel located on the inner side of the upper part of the cage frustum, the top of the coarse particle separation rotating cage is provided with an upper ring plate, the middle is provided with a middle ring plate, and the bottom is provided with a lower ring plate, the coarse particle grading vanes are located between the upper ring plate, the middle ring plate and the lower ring plate, and are close to the outer edges of the upper ring plate, the middle ring plate and the lower ring plate and are uniformly distributed in a radial manner; a support cover plate is arranged above the coarse particle separation shell and the coarse particle grading vanes, the bottom surface of the support cover plate is fixedly connected with the coarse particle separation shell, and the bottom surface of the support cover plate and the upper ring plate of the coarse particle separation rotating cage are connected in a dynamic sealing form to form an outer seal of the rotating cage of the coarse particle separation rotating cage; and the support cover plate, the coarse particle separation shell and the coarse particle grading vanes jointly form the coarse particle grading area.

[0008] The material distribution device comprises a material distribution disc cone and a material distribution disc bottom plate, the material distribution disc cone is coaxially arranged below the cage cone, the bottom end outer edge of the material distribution disc cone is connected with the material distribution disc bottom plate, and the material distribution disc bottom plate and the lower ring plate form a material flow distribution channel; a material lifting platform is arranged between the coarse particle sorting shell and the air inlet shell, the material lifting platform is located at the outer side of the material flow distribution channel and is adjacent to the annular air ring at the lower side; the material distribution disc bottom plate and the air ring inner ring of the annular air ring are connected in a dynamic sealing mode to form a dynamic sealing of the material distribution device.

[0009] The coarse particle sorting drive is connected with the coarse particle sorting rotating cage and the material distribution disc cone through a shaft system, and is used for driving the coarse particle sorting rotating cage and the material distribution disc cone to rotate.

[0010] The feeding and medium-coarse powder return connection area and the medium-coarse powder and fine powder classification area comprise a feeding pipe, a medium-coarse powder return pipe and a fine classification device, the feeding pipe passes through the fine classification shell of the fine classification device and is connected with the inside of the cage cone through an inner connecting pipe, the inner connecting pipe and the cage cone are connected in a dynamic sealing mode to form an inner sealing of the rotating cage of the coarse particle sorting rotating cage; one end of the medium-coarse powder return pipe is connected with a medium-coarse powder return cone hopper of the fine classification device, and the other end of the medium-coarse powder return pipe passes out of the fine classification shell; the medium-coarse powder return cone hopper is connected with the inside of the cage cone or is not connected with the inside of the cage cone, and the fine classification shell is connected with a support cover plate to form a dust-containing air flow rising channel.

[0011] Preferably, the feeding pipe is located directly above the center of the coarse particle sorting rotating cage, and the fine classification shell is connected with the support cover plate through an outer connecting air pipe;

[0012] An inner sealing ring of the rotating cage is arranged at the outer edge of the cage cone and is close to the inner connecting pipe, the inner sealing ring of the rotating cage and the inner connecting pipe cooperate to form the inner sealing of the rotating cage of the coarse particle sorting rotating cage, the dynamic sealing gap of the inner sealing is 10-20 mm, and the radial positions of the inner sealing ring of the rotating cage and the inner connecting pipe are interchangeable;

[0013] The bottom surface of the support cover plate is fixedly connected with an outer sealing outer ring located at the outer side of the upper ring plate and an outer sealing inner ring located at the inner side of the upper ring plate, the outer sealing outer ring and the outer sealing inner ring cooperate with the upper ring plate to form a rotating cage outer sealing, and the dynamic sealing gap of the rotating cage outer sealing is 10-20 mm;

[0014] The outer edge of the lower side of the material distribution disc bottom plate is fixedly connected with a dynamic sealing outer ring of the material distribution device, the inner ring of the air ring of the annular air ring is provided with a dynamic sealing inner ring of the material distribution device, the dynamic sealing outer ring of the material distribution device cooperates with the dynamic sealing inner ring of the material distribution device to form a dynamic sealing of the material distribution device, and the dynamic sealing gap of the dynamic sealing of the material distribution device is 10-20 mm.

[0015] Preferably, the upper ring plate is connected to the cage cone through a rotating cage pull rod, the rotating cage pull rod is arranged in the same direction as the rotating direction of the coarse particle separation rotating cage and is uniformly distributed along the axis of the coarse particle separation rotating cage; the inner edge of the lower ring plate is connected to the cage cone; the inner edge of the middle ring plate is connected to the cage cone through a pull rod or a rib plate.

[0016] Preferably, the feeding pipe at the feeding position of the coarse-fine gradient classification powder separator can be cancelled and replaced by being connected in series with other static separation equipment or grinding equipment to introduce the dust-containing air flow in the form of air sweeping.

[0017] Preferably, the coarse particle separation rotating cage and the distribution disc cone are driven by the same drive, and at this time, the shaft system one includes a main shaft and a main shaft sleeve sleeved on the main shaft, the top of the main shaft is provided with a hub, the upper part of the hub is connected to the scattering round steel, the lower part of the hub is connected to the distribution disc cone, and the top of the hub is provided with a wear-resistant cap.

[0018] Preferably, the coarse particle separation rotating cage and the distribution disc cone are driven by two drives respectively, and at this time, the coarse particle separation drive includes independent drive one and independent drive two, the shaft system one includes an inner transmission shaft and an outer transmission sleeve shaft, the upper end of the inner transmission shaft is connected to the scattering round steel through a hub, and the lower end is connected to independent drive one; the outer transmission sleeve shaft is sleeved on the inner transmission shaft, the upper end of the outer transmission sleeve shaft is connected to the distribution disc cone, and the lower end is connected to independent drive two through a belt pulley set.

[0019] Preferably, the air distribution and distribution area and the pre-scattering and coarse particle classification area can be used independently as two parts, which are arranged at different heights according to process requirements, at this time, the medium-coarse powder return cone is not connected to the inside of the cage cone, the outer connecting air pipe is replaced by a non-standard connecting air pipe, and the air distribution and distribution area and the pre-scattering and coarse particle classification area are connected to the medium-coarse powder and fine powder classification area through the non-standard connecting air pipe.

[0020] Preferably, the air inlet is connected to the classification equipment or the grinding equipment, and the dust-containing air flow to be separated is introduced into the air inlet shell in the form of air sweeping.

[0021] Preferably, a ring-shaped "staircase" scattering device or a ring-shaped "Z" scattering device is arranged below the ring-shaped air ring and in the inner cavity of the air inlet shell.

[0022] The scattering plates of the ring-shaped "staircase" scattering device are arranged in a stepped structure with a certain spacing, the overlapping distance of the projection of the generatrix of two adjacent scattering plates is 100-200 mm, each scattering plate is supported on the inner wall of the air inlet shell through a supporting device, and the scattering plates are connected through connecting rib plates.

[0023] The part of the scattering plate of the annular "Z"-shaped scattering device is supported on the inner wall of the air inlet shell by the supporting device, and the part is supported on the outer wall of the flow guide cone by the supporting device. The two sides of the scattering plate are arranged in a stepped structure with a certain interval. The scattering grading channels are formed between the two adjacent scattering plates. The projection point of the end of the previous scattering plate on the next scattering plate is 100-200 mm away from the end of the scattering plate. The angle θ9 between the scattering plate of the annular "ladder"-shaped scattering device and the annular "Z"-shaped scattering device and the horizontal direction is 40-50°.

[0024] Preferably, the annular air ring comprises an air ring inner ring, an air ring outer ring, and a plurality of air ring guide vanes obliquely arranged between the air ring inner ring and the air ring outer ring. The gap air speed of the air ring guide vanes is 18±2 m / s. The angle θ2 between the air ring guide vanes and the horizontal direction is 35-45°. The ratio of the horizontal projection overlap length of the adjacent two air ring guide vanes to the horizontal projection length of a single air ring guide vane is S1:S2=0.3-0.8.

[0025] Preferably, when the coarse particle sorting rotating cage and the distributing device are driven by the same drive, the material flow distributing channel is uniformly distributed with a distributing round steel. The top end of the distributing round steel is connected with the lower ring plate, and the bottom end is connected with the distributing disc bottom plate.

[0026] Preferably, the bottom end of the flow guide cone is connected with a coarse material guide cone.

[0027] Preferably, when the medium-coarse powder return cone hopper is in communication with the inside of the cage cone, a return control device is arranged in the medium-coarse powder return cone hopper. The return control device comprises a medium-coarse powder guide cone, and a medium-coarse powder overflow hole is arranged on the medium-coarse powder guide cone, so that the return control device is in communication with the inside of the cage cone. An annular area for collecting medium-coarse powder is formed between the medium-coarse powder guide cone and the medium-coarse powder return cone hopper. A plurality of material distribution cones are uniformly arranged in the circumferential direction in the annular area. The material distribution cone is a ridge-shaped structure formed by two plates. The material distribution cone and the medium-coarse powder guide cone together divide the annular area into several funnel-shaped material areas. A return pipe interface is arranged at the bottom of each funnel-shaped material area. The return pipe interface is in the shape of a large upper funnel. A medium-coarse powder return pipe is connected to the lower end of the return pipe interface. A medium-coarse powder return control valve is arranged on the medium-coarse powder return pipe.

[0028] The classification method of the above-mentioned coarse-fine gradient classification powder separator, the material to be sorted is fed into the pre-dispersion and coarse particle classification zone inside the equipment by the feeding pipe of the feeding and medium-coarse powder return connection area, dispersed onto the dispersion round steel inside the coarse particle sorting rotating cage, fully dispersed by the dispersion round steel, and then evenly distributed and thrown onto the material distribution table by the lower rotating material distribution cone and the material distribution bottom plate, and then falls onto the annular air ring of the air distribution area, and then impacts the air ring guide blade, and then is fully dispersed again by the air ring guide blade, so that the fine particles mixed between the material flow and the fine powder adhered to the surface of the coarse particles are fully dispersed and separated; the sorting airflow enters from the air inlet and is evenly distributed, and then enters the annular air ring, concentrates and blows the dispersed material by the air ring guide blade, completes the first coarse particle classification, most of the coarse particles return to the material bed of the grinding equipment under the action of gravity to continue grinding, and a small part of the coarse particles and most of the medium-coarse powder and fine powder pass through the annular air ring upwards to complete the second coarse-fine particle classification in the coarse particle sorting rotating cage; the dust-containing airflow after sorting enters the subsequent medium-coarse powder and fine powder classification zone along the dust-containing airflow upward channel, and the dust-containing airflow passing through the static blade is finely classified by the fine classification device, wherein the sorted fine powder is collected as a finished product, and the medium-coarse powder enters the fine grinding equipment for further grinding through the return control device, the medium-coarse powder return control valve and the medium-coarse powder return pipe; or the medium-coarse powder returns to the pre-dispersion and coarse particle classification zone below through the medium-coarse overflow hole by adjusting the opening degree of the medium-coarse powder return control valve for secondary sorting.

[0029] The design method of the above-mentioned coarse-fine gradient classification powder separator, comprising setting the following process structure parameters:

[0030] 1) System powder selection air volume Q (m 3 / h) :

[0031] According to the system design output P (t / h), the system circulating load k, the powder selection concentration C s (g / m 3 ), the feeding concentration F s (kg / m 3 ), the system powder selection air volume Q (m 3 / h) is calculated:

[0032]

[0033] Among them, the system circulating load k = 3 ± 1, the powder selection concentration C s = 800 ± 200 g / m 3 , the feeding concentration F s = 2.5 ± 0.5 kg / m 3 .

[0034] 2) Coarse particle sorting rotating cage diameter D1 (mm) :

[0035]

[0036] Wherein, the diameter-height ratio D / H of the coarse particle sorting rotating cage is 1.8-2.0, and the radial wind speed V2 of the coarse particle sorting rotating cage is 1.5-2.5 (m / s).

[0037] 3) Height H1 (mm) of the coarse particle sorting rotating cage:

[0038]

[0039] 4) Outer diameter D2 (mm) of the bottom plate of the center feeding cloth disc:

[0040] D2=D1-(0-50) (4)

[0041] 5) Inner diameter D6 (mm) of the wind ring:

[0042] D6=D2-(40-60) (5)

[0043] 6) Outer diameter or inner diameter D7 (mm) of the air inlet shell:

[0044]

[0045] Wherein, V3=10±2 is the outlet wind speed of the annular wind ring (m / s);

[0046] 7) Diameter D8 (mm) of the interface of the guide cone and the coarse material guide cone:

[0047]

[0048] Wherein, V5=4±1 is the inlet wind speed (m / s);

[0049] 8) Diameter D5 (mm) of the upper end of the inner cavity of the coarse particle sorting shell:

[0050] D5=D1+(400±100) mm (8)

[0051] 9) Diameter D4 (mm) of the inner connecting pipe:

[0052]

[0053] Wherein, the system circulation load k=3±1, the material bulk density ρ s =1.5-1.8 (t / m3), the material flow rate V s =1±0.5 (m / s), and the material filling rate ε=0.5-0.8;

[0054] 10) Diameter D3 (mm) of the outer connecting air pipe:

[0055]

[0056] Wherein, V1 = 10 ~ 15 is the coarse particle sorting rotating cage outlet air speed (m / s) ;

[0057] 11) The number of medium coarse powder return pipe n1 (pieces), the number of medium coarse powder overflow hole n2 (pieces) :

[0058] n1 = n2 = 3 ± 1 (11)

[0059] 12) The diameter of the medium coarse powder return pipe d2 (mm) :

[0060]

[0061] Wherein, the system cycle load k = 3 ± 1, the material bulk density ρ s = 1.5 ~ 1.8 (t / m 3 ), the material flow rate V s = 1 ± 0.5 (m / s), the material filling rate ε = 0.5 ~ 0.8, the number of medium coarse powder return pipe n1 = 3 (pieces) ;

[0062] 13) The diameter of the medium coarse powder overflow hole d3 (mm) :

[0063] d3 = d2 (13)

[0064] 14) The gap H2 (mm) between the lower ring plate and the distributor bottom plate:

[0065] H2 = 300 ± 50 (mm) (14)

[0066] 15) The gap H3 (mm) between the distributor bottom plate and the annular air ring outlet:

[0067] H3 = 100 ± 50 (mm) (15)

[0068] 16) The number of air ring guide vane n3 (pieces) :

[0069]

[0070] Wherein, d1 is the gap between the adjacent two air ring guide vanes, d1 = 100 ~ 200 (mm), V4 is the gap air speed of the air ring guide vane, V4 = 18 ± 2 (m / s), n3 is the integer;

[0071] 17) The height of the annular air ring H4 (mm) :

[0072]

[0073] Wherein, θ2=40±5 is the angle between the wind ring guide vane and the horizontal direction (°), S1 / S2=0.3~0.8 is the ratio of the overlapping length of the horizontal projection of the adjacent two wind ring guide vanes to the horizontal projection length of a single wind ring guide vane, and t=10~20 (mm) is the thickness of the wind ring guide vane.

[0074] 18) Height H5 (mm) of the material lifting platform:

[0075] H5=(1.2±0.1)(H2+H3) (18)

[0076] 19) Vertical gap H6 (mm) between the lower edge of the coarse and medium powder overflow hole and the upper edge of the material return pipe interface:

[0077] H6=300±50 (19)

[0078] 20) Vertical gap H7 (mm) between the lower edge of the material return pipe interface and the upper edge of the inner connecting pipe:

[0079] H7=200±50 (20)

[0080] 21) Angle θ1 (°) between the inner ring of the wind ring and the horizontal direction:

[0081] θ1=60±10 (21)

[0082] 22) Angle θ3 (°) between the guide cone and the horizontal direction:

[0083] θ3=60±10 (22)

[0084] 23) Angle θ4 (°) between the material lifting platform and the horizontal direction:

[0085] θ4=50±5 (23)

[0086] 24) Angle θ5 (°) between the coarse material guide cone and the horizontal direction:

[0087] θ5=60±5 (24)

[0088] 25) Angle θ6 (°) between the coarse particle separation shell and the horizontal direction:

[0089] θ6=70±5 (25)

[0090] 26) Angle θ7 (°) between the medium and coarse powder guide cone and the horizontal direction:

[0091] θ7=65±10 (26)

[0092] 27) Angle θ8 (°) between the line connecting the lower edge of the medium and coarse powder overflow hole and the upper edge of the medium and coarse powder material return cone and the horizontal direction:

[0093] θ8=45±10 (27)

[0094] 28) The lower end diameter of the dispersing plate of the annular "ladder" shaped dispersing device, from top to bottom, is D9 (mm), D 10 (mm), D 11 (mm), D 12 (mm):

[0095]

[0096] D 12 = D8 + (500-600) (29)

[0097]

[0098]

[0099] 29) The gap between two adjacent dispersing plates of the annular "ladder" shaped dispersing device, from top to bottom, is d4 (mm), d5 (mm), d6 (mm):

[0100]

[0101] Wherein, V6 = 14 ± 2 is the annular "ladder" shaped dispersing device blowing wind speed (m / s);

[0102] 30) The lower end diameter of the dispersing plate of the annular "Z" shaped dispersing device, from top to bottom, is D 13 (mm), D 14 (mm), D 15 (mm), D 16 (mm):

[0103]

[0104]

[0105] 31) The gap between two adjacent dispersing plates of the annular "Z" shaped dispersing device, from top to bottom, is d7 (mm), d8 (mm), d9 (mm):

[0106]

[0107]

[0108]

[0109] Wherein, V7 = 14 ± 2 is the annular "Z" shaped dispersing device blowing wind speed (m / s);

[0110] 32) The overlap distances of the generatrix projections of two adjacent dispersing plates in the annular "stepped" dispersing device, from top to bottom, are S3 (mm), S4 (mm), and S5 (mm):

[0111] S3=S4=S5=150±50 (38)

[0112] If S3, S4, and S5 do not meet the requirements of equation (38), then D9 and D can be adjusted appropriately. 10 D 11 Calculated value;

[0113] 33) The distances from the projection point of the end of the upper dispersing plate onto the lower dispersing plate of the annular "Z"-shaped dispersing device to the end of the dispersing plate, from top to bottom, are S7 (mm), S8 (mm), and S9 (mm):

[0114] S7=S8=S9=150±50 (39)

[0115] If S7, S8, and S9 do not meet the requirements of equation (39), then D can be adjusted appropriately. 14 D 15 D 16 Calculated value;

[0116] 34) The angle θ9 (°) between the dispersing plates of the annular "stepped" shaped dispersing device and the annular "Z" shaped dispersing device and the horizontal direction:

[0117] θ9=45±5 (40).

[0118] The advantages and positive effects of this invention are:

[0119] The present application can completely shield the coarse particles by setting the coarse particle separation rotating cage and forming the forced vortex field by independent driving, so that the coarse particles do not enter the subsequent fine powder classification process, thereby realizing coarse-to-fine gradient classification and meeting the grinding requirements of different equipment in the combined / semi-final grinding system; the inside scattering round steel of the coarse particle separation rotating cage can break the material cake formed by the material bed extrusion equipment, thereby shortening the huge height difference required for static scattering, reducing the floor height and saving the construction cost; the material distribution disc is arranged below the coarse particle separation rotating cage, which can uniformly throw and scatter the broken material cake to the annular air ring, which is beneficial to the settlement of coarse particles at the annular air ring and the lifting of medium-coarse powder and fine powder; the flow guide cone and the annular air ring are arranged, compared with the traditional V-type powder separator, the airflow field distribution is more uniform, the coarse particle cutting particle size is more definite, the coarse particles brought into the separation zone are reduced, the circulating load and material concentration are reduced, the equipment resistance is reduced, and the circulating fan power consumption is reduced. The coarse-to-fine gradient classification powder separator has compact structure, solves the problems of uneven airflow and material flow of the traditional V-type powder separator, realizes accurate classification of coarse particles, medium-coarse powder and fine powder, and has performance completely superior to the traditional V-type powder separator and the fine dynamic powder separator in series, and can replace them. BRIEF DESCRIPTION OF DRAWINGS

[0120] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application, the drawings needed in the following specific embodiment description will be briefly introduced. Obviously, the drawings in the following description are some specific embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0121] Figure 1 is a structural schematic diagram of the coarse-to-fine gradient classification powder separator of the present application;

[0122] Figure 2 is Figure 1 A-A view in the present application;

[0123] Figure 3 is a partial detail view of part A in the present application; Figure 1

[0124] Figure 4 is a partial detail view of part B in the present application; Figure 1

[0125] Figure 5 is a partial detail view of part C in the present application; Figure 1

[0126] Figure 6 is a structural schematic diagram of the air distribution and material distribution area, pre-scattering and coarse particle classification area of the present application;

[0127] Figure 7 is Figure 6 B-B view in the present application;​​​

[0128] Figure 8 is Figure 6 C-C view in the middle;

[0129] Figure 9 is a schematic diagram of the independent driving structure of the coarse particle sorting rotating cage and the distributing device of the present application;

[0130] Figure 10 is a schematic diagram of the independent partition structure of the coarse and fine gradient grading powder selecting machine of the present application;

[0131] Figure 11 is a schematic diagram of the structure of the coarse and fine gradient grading powder selecting machine of the present application in the form of wind sweeping to introduce dust-containing air flow;

[0132] Figure 12 is a schematic diagram of the structure of the ring-shaped "ladder" type scattering device of the present application;

[0133] Figure 13 is a schematic diagram of the structure of the ring-shaped "Z" type scattering device of the present application;

[0134] Figure 14 is a schematic diagram of the process structure parameters of the coarse and fine gradient grading powder selecting machine of the present application;

[0135] Figure 15 is a schematic diagram of the process structure parameters of the ring-shaped "ladder" type scattering device of the present application;

[0136] Figure 16 is a schematic diagram of the process structure parameters of the ring-shaped "Z" type scattering device of the present application.

[0137] 1, fine classification drive; 2, fine classification housing; 3, fine powder sorting rotating cage; 4, stationary blade; 5, return material control device; 6, medium and coarse powder return pipe; 7, inner connecting pipe; 8, feeding pipe; 9, outer connecting air pipe; 10, air distribution and material distribution area and pre-dispersion and coarse particle classification area; 11, upper bearing seat; 12, rotating cage pull rod; 13, dispersion round steel; 14, wheel hub; 15, wear-resistant cap; 16, rotating cage inner seal; 16-1, rotating cage inner seal ring; rotating 17, upper ring plate; 18, rotating cage outer seal; 18-1, outer seal outer ring; 18-2, outer seal inner ring; 19, support cover plate; 20, middle ring plate; 21, coarse particle classification blade; 22, lower ring plate; 23, material distribution round steel; 24, material distribution disc bottom plate; 25, annular air ring; 26, upper bearing seat support table; 27, air inlet housing; 28, coarse particle outlet; 29, drive device base; 30, material distribution disc cone; 31, cage cone; 32, bearing seat support; 33, ear plate; 34, material lifting table; 35, main shaft sleeve; 36, flow guide cone; 37, lower bearing seat; 38, coarse material guide cone; 39, equipment foundation support; 40, support flange; 41, main shaft; 42, coarse particle sorting drive; 43, return material chute; 44, return material pipe interface; 45, material distribution cone; 46, medium and coarse powder guide cone; 47, air inlet; 48, air ring outer ring; 49, air ring air guide blade; 50, air ring inner ring; 51, coarse particle sorting rotating cage; 52, material distribution device; 53, inner transmission shaft; 54, outer transmission sleeve shaft; 55, belt pulley set; 56, independent drive one; 57, independent drive two; 58, medium and coarse powder classification area; 59, support; 60, medium and coarse powder return cone hopper; 61, built-in pipe; 62, non-standard connecting air pipe; 63, pipe seal; 64, material scattering inverted cone; 65, medium and coarse powder overflow hole; 66, medium and coarse powder return control valve; 67, classification equipment or grinding equipment; 68, support device; 69, connecting rib plate; 70, annular "step" shape dispersion device; 71, dispersion plate; 72, annular "Z" shape dispersion device; 73, material distribution device dynamic seal outer ring; 74, material distribution device dynamic seal inner ring; 75, coarse particle sorting housing. DETAILED DESCRIPTION

[0138] The technical solutions of the present application will be described clearly and completely below in combination with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0139] In the description of the present application, it is to be understood by those skilled in the art that the terms "upper", "lower", "front", "back", "left", "right", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0140] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0141] Embodiment

[0142] Please refer to Figures 1-13 The embodiment of the present application provides a coarse and fine gradient grading powder selecting machine, which is formed from bottom to top in sequence of air distribution material distribution area, pre-scattering and coarse particle grading area, feeding and medium coarse powder return connection area, medium coarse powder and fine powder grading area; wherein, the air distribution material distribution area and the pre-scattering and coarse particle grading area 10 (double-dot line circled part) are the core part of the present application.

[0143] The air distribution material distribution area is located at the bottom of the equipment, including an air inlet shell 27, an air inlet 47, a coarse particle outlet 28, a flow guide cone 36 and an annular air ring 25. The air inlet shell 27 surrounds the outermost part to form a closed flow guide scattering and sorting space, and the air inlet shell 27 is located on the equipment foundation support 39. The air inlet 47 is located on the side of the air inlet shell 27, and the air inlet form of the air inlet 47 is tangential air inlet or vertical air inlet. The coarse particle outlet 28 is located at the bottom of the air inlet shell 27, and the coarse particle outlet 28 is provided with a plurality of coarse particle outlets, which are distributed in a mirror image to avoid interference with the underlying coarse particle sorting drive 42. The flow guide cone 36 is coaxially arranged inside the air inlet shell 27, and the shape of the flow guide cone 36 is inverted round table type or cylindrical shape.

[0144] The annular air ring 25 is installed between the outer edge of the guide cone 36 and the inner edge of the top of the air inlet shell 27, is adjacent to the annular air ring 25 above the guide cone 36, and is close to the lower edge of the material lifting platform 34 on the outer side of the upper edge of the annular air ring 25 and is close to the inner wall of the air inlet shell 27. The inner side of the upper edge of the annular air ring 25 is connected to the upper bearing seat support platform 26. The annular air ring 25 comprises an air ring inner ring 50, an air ring outer ring 48, and a plurality of air ring guide vanes 49 obliquely arranged between the air ring inner ring 50 and the air ring outer ring 48. The lower edge of the air ring inner ring 50 is fixedly connected to the upper edge of the guide cone 36, and the upper bearing seat support platform 26 is fixedly connected to the upper edge of the air ring inner ring 50.

[0145] The gap air speed of the air ring guide vane 49 is 18±2m / s; the included angle θ2 between the air ring guide vane 49 and the horizontal direction is 35-45°; and the ratio of the overlapping length of the horizontal projection of the adjacent two air ring guide vanes 49 to the horizontal projection length of a single air ring guide vane 49 is S1:S2=0.3-0.8.

[0146] The annular air ring 25 is installed between the outer edge of the guide cone 36 and the inner edge of the top of the air inlet shell 27, is adjacent to the annular air ring 25 above the guide cone 36, and is close to the lower edge of the material lifting platform 34 on the outer side of the upper edge of the annular air ring 25 and is close to the inner wall of the air inlet shell 27. The inner side of the upper edge of the annular air ring 25 is connected to the upper bearing seat support platform 26. The annular air ring 25 comprises an air ring inner ring 50, an air ring outer ring 48, and a plurality of air ring guide vanes 49 obliquely arranged between the air ring inner ring 50 and the air ring outer ring 48. The lower edge of the air ring inner ring 50 is fixedly connected to the upper edge of the guide cone 36, and the upper bearing seat support platform 26 is fixedly connected to the upper edge of the air ring inner ring 50.

[0147] The distributing device 52 comprises a distributing disc cone 30 coaxially arranged below the cage cone 31, and a distributing disc bottom plate 24 connected to the outer edge of the bottom end of the distributing disc cone 30. The distributing disc bottom plate 24 and the lower ring plate 22 form a material flow distributing channel. A plurality of distributing round steels 23 are evenly distributed around the material flow distributing channel. The top end of each distributing round steel 23 is connected to the lower ring plate 22, and the bottom end is connected to the distributing disc bottom plate 24. The distributing round steels 23 connect the distributing disc bottom plate 24 and the lower ring plate 22 into a whole body while distributing the material. If the coarse particle sorting rotating cage 51 and the distributing device 52 are independently driven, the distributing round steels 23 are cancelled. A distributing device dynamic sealing outer ring 73 is fixedly connected to the outer edge of the lower side of the distributing disc bottom plate 24. A distributing device dynamic sealing inner ring 74 is arranged on the inner ring 50 of the annular air ring 25. The distributing device dynamic sealing outer ring 73 and the distributing device dynamic sealing inner ring 74 jointly constitute a distributing device dynamic sealing. The dynamic sealing gap of the distributing device dynamic sealing is 10-20 mm, which prevents the material to be sorted from being discharged from the system through the inner ring 50 of the air ring and the flow guide cone 36. Specifically, the distributing device dynamic sealing inner ring 74 is fixedly connected to the top end of the inner ring 50 of the air ring and abuts against the outer edge of the upper bearing seat support platform 26. The distributing device dynamic sealing outer ring 73 is fixedly connected to the outer edge of the lower side of the distributing disc bottom plate 24.

[0148] The coarse particle sorting drive 42 is connected to the coarse particle sorting rotating cage 51 and the distributing disc cone 30 through a shafting I, and is used for driving the coarse particle sorting rotating cage 51 and the distributing disc cone 30 to rotate. The coarse particle sorting drive 42 is arranged directly below the flow guide cone 36. The bottom end of the flow guide cone 36 is connected to a coarse material guide cone 38. The flow guide cone 36 and the coarse material guide cone 38 jointly isolate the material flow and the air flow outside the shafting I.

[0149] The feeding and medium-coarse powder return connection area and the medium-coarse powder and fine powder classification area 58 comprise a feeding pipe 8, a medium-coarse powder return pipe 6, and a fine classification device. The feeding pipe 8 penetrates through the fine classification shell of the fine classification device and is in communication with the inside of the cage cone 31. One end of the medium-coarse powder return pipe 6 is connected to the lower part of a medium-coarse powder return cone hopper 60 of the fine classification device, and the other end penetrates out of the fine classification shell. The medium-coarse powder return pipe 6 is evenly distributed at equal angles. The medium-coarse powder return cone hopper 60 is in communication or not in communication with the inside of the cage cone 31. The fine classification shell is connected to the support cover plate 19 to form a dust-containing air flow rising channel.

[0150] The fine grading device includes a fine grading shell 2, stationary blades 4, a fine powder sorting drum 3, a medium-coarse powder return cone 60, and a fine grading drive 1. The stationary blades 4 and the fine powder sorting drum 3 are both located on the inner side of the middle of the fine grading shell 2. The stationary blades 4 are concentrically distributed around the outer periphery of the fine powder sorting drum 3. A fine powder outlet is provided on the fine grading shell 2 above the fine powder sorting drum 3. The top of the medium-coarse powder return cone 60 is connected to the bottom of the stationary blades 4. The fine grading drive 1 is connected to the fine powder sorting drum 3 and is located on the fine grading shell 2 above the fine powder outlet.

[0151] Specifically, the feeding pipe 8 is located directly above the center of the coarse particle sorting drum 51. The feeding pipe 8 is connected to the inside of the drum cone 31 via an inner connecting pipe 7. The feeding pipe 8 is inserted into the inner connecting pipe 7 and feeds the material to be sorted into the drum cone 31 for pre-dispersion through the inner connecting pipe 7. The inner connecting pipe 7 separates the fed material flow from the external airflow. The fine grading shell is connected to the support cover plate 19 via an external connecting air duct 9. The lower part of the external connecting air duct 9 is connected to the support cover plate 19, and the upper part is connected to the fine grading shell. The inner connecting pipe 7 and the external connecting air duct 9 form a dust-laden airflow rising channel. Figure 5 As shown, a rotating cage inner seal 16 is provided around the outer edge of the cage cone 31 near the inner connecting material pipe 7. It consists of a rotating cage inner sealing ring 16-1 and the inner connecting material pipe 7. The rotating cage inner sealing ring 16-1 is provided around the outer edge of the cage cone 31 near the inner connecting material pipe 7. The rotating cage inner sealing ring 16-1 and the inner connecting material pipe 7 cooperate to form the rotating cage inner seal 16 of the coarse particle sorting rotating cage. The dynamic sealing gap of the rotating cage inner seal 16 is 10-20mm to prevent the sorted medium and coarse powder and the material to be sorted from entering each other in the opposite direction. The radial positions of the rotating cage inner sealing ring 16-1 and the inner connecting pipe 7 are interchangeable.

[0152] like Figure 3 As shown, a rotating cage outer seal 18 is provided around the bottom surface of the support cover plate 19 near the inner and outer edges of the upper ring plate 17. This seal consists of an outer sealing ring 18-1, an inner sealing ring 18-2, and the upper ring plate 17. The outer sealing ring 18-1 is fixed to the bottom surface of the support cover plate 19 and located at the outer edge of the upper ring plate 17. The inner sealing ring 18-2 is also fixed to the bottom surface of the support cover plate 19 and located at the inner edge of the upper ring plate 17. The outer sealing ring 18-1 and the inner sealing ring 18-2, together with the upper ring plate 17, form the rotating cage outer seal 18. The dynamic sealing gap of the rotating cage outer seal 18 is 10-20 mm to prevent coarse particles from directly passing through the coarse particle sorting rotating cage 51 without being sorted and entering the subsequent sorting process. Both the inner seal 16 and the outer seal 18 are dynamic seals, ensuring that the coarse particle sorting rotating cage 51 does not interfere or collide during rotation.

[0153] like Figure 6As shown, the upper ring plate 17 is connected to the cage cone 31 via the rotating cage tie rod 12. The arrangement direction of the rotating cage tie rod 12 is consistent with the rotation direction of the coarse particle sorting rotating cage 51 and is evenly distributed along the axis of the coarse particle sorting rotating cage 51. The inner edge of the lower ring plate 22 is connected to the cage cone 31. The outer edge of the middle ring plate 20 is connected to the coarse particle grading blade 21, and the inner edge is connected to the cage cone 31 via tie rods or stiffeners. The middle ring plate 20 strengthens and fixes the coarse particle grading blade 21. The upper ring plate 17, middle ring plate 20, and lower ring plate 22 are located at the upper, middle, and lower parts of the coarse particle sorting rotating cage 51, respectively. The upper ring plate 17, middle ring plate 20, lower ring plate 22, rotating cage tie rod 12, and cage cone 31 together constitute the cage frame.

[0154] like Figure 6 As shown, the coarse particle sorting drum 51 and the feeding disc cone 30 are driven by the same drive. At this time, the shaft system includes a main shaft 41 and a main shaft sleeve 35 sleeved on the main shaft 41. A hub 14 is provided on the top of the main shaft 41. The upper part of the hub 14 is connected to the dispersing round steel 13, and the lower part of the hub 14 is connected to the feeding disc cone 30. An anti-wear cap 15 is provided on the top of the hub 14. Specifically, the upper part of the main shaft 41 is supported by a bearing assembly installed in the upper bearing seat 11, and the lower part is supported by a bearing assembly installed in the lower bearing seat 37. The upper and lower bearing seats are arranged coaxially. There are bearing seat supports 32 around the outer side of the upper bearing seat 11. The bearing seat supports 32 are connected to the ear plate 33. The ear plate 33 is connected to the upper bearing seat support platform 26. The radial force is transmitted to the air inlet shell 27 through the upper bearing seat support platform 26 and the annular air ring 25. A support flange 40 is provided on the outer side of the lower bearing seat 37. The support flange 40 is connected to the equipment foundation support 39. The axial force is transmitted to the civil foundation through the equipment foundation support 39. The drive device base 29 is connected below the equipment foundation support 39. The lower coarse particle sorting drive 42 is connected below the drive device base 29. The lower coarse particle sorting drive 42 is the power source for the entire coarse particle sorting drum 51 and the feeding disc cone 30.

[0155] To further achieve precise sorting of coarse particles and optimal fabric rotation speed, the coarse particle sorting drum 51 and the fabric disc cone 30 can be driven independently. Specifically, as shown below... Figure 9As shown, the coarse particle sorting rotating cage 51 and the distributing disc cone 30 are driven independently by two drives, and the coarse particle sorting drive includes independent drive one 56 and independent drive two 57. The shaft system one includes an inner transmission shaft 53 and an outer transmission sleeve shaft 54. The upper end of the inner transmission shaft 53 is connected to the scattering round steel 13 through the hub 14, and the lower end is connected to the independent drive one 56, which can be variable frequency speed regulation. The outer transmission sleeve shaft 54 is sleeved on the inner transmission shaft 53, and the upper end of the outer transmission sleeve shaft 54 is connected to the distributing disc cone 30, and the lower end is connected to the independent drive two 57 through the belt pulley set 55. The independent drive two 57 can be variable frequency speed regulation. Specifically, the inner transmission shaft 53 is supported by the upper and lower bearings or the upper, middle and lower bearing assemblies matched therewith, and the upper bearing assembly can be located on the upper part of the bearing seat 11 of the distributing disc cone 30 or inside the bearing seat 11 of the distributing disc cone 30. The outer transmission sleeve shaft 54 is supported by the upper and lower bearings or the upper, middle and lower bearing assemblies matched therewith, and the upper bearing assembly is located inside the bearing seat 11 of the distributing disc cone 30. The coarse particle sorting rotating cage 51 and the distributing disc cone 30 can be independently adjusted in speed according to different requirements of the distributing disc cone 30 for the speed, and the entire device is in a three-drive form.

[0156] As shown in Figure 11 In order to further realize more stages of sorting or ultra-fine sorting, a dust-containing air flow can be introduced in series with a classification device or a grinding device 67 in a wind sweeping form. Specifically, the air inlet 47 is connected to a classification device (such as a static powder concentrator) or a grinding device (such as a wind sweeping mill), and a dust-containing air flow to be sorted is introduced into the air inlet shell 27 in a wind sweeping form.

[0157] As shown in Figure 1 When the medium-coarse powder return cone 60 is in communication with the inside of the cage cone 31, the return control device 5 is arranged in the medium-coarse powder return cone 60. The return control device 5 includes a medium-coarse powder guide cone 46, and the medium-coarse powder guide cone 46 is provided with a medium-coarse powder overflow hole 65, so that the return control device 5 is in communication with the inside of the cage cone 31.

[0158] The annular area for collecting the medium-coarse powder is formed between the medium-coarse powder guide cone 46 and the medium-coarse powder return cone bucket 60, and a plurality of distribution cones 45 are uniformly arranged in the annular area in the circumferential direction. The distribution cone 45 is in a ridge shape formed by two plates being overlapped together, and the distribution cone 45 together with the centrally-located medium-coarse powder guide cone 46 divides the annular area into several funnel-shaped material areas. Each of the funnel-shaped material areas is provided with a return pipe interface 44 at the bottom, and the return pipe interface 44 is in a funnel shape with the upper part being large and the lower part being small, so that the material accumulation can be completely avoided. The lower end of the return pipe interface 44 is connected with a return chute pipe 43, and the lower end of the return chute pipe 43 is connected with a medium-coarse powder return pipe 6. The return chute pipe 43 and the medium-coarse powder return pipe 6 are connected by bolts, and the position and angle of the medium-coarse powder return pipe 6 can be adjusted according to the required material flow direction. The medium-coarse powder return control valve 66 is arranged on the medium-coarse powder return pipe 6, and the opening degree of the medium-coarse powder return control valve 66 is adjusted to realize that part of the medium-coarse powder returns to the lower pre-dispersion and coarse particle classification area for secondary separation through the medium-coarse powder overflow hole 65 of the medium-coarse powder guide cone 46.

[0159] As shown in Figure 10 , in order to further realize the flexible arrangement requirement of the coarse particle separation part and the medium-coarse powder and fine powder separation part, specifically, the air distribution and material distribution area and the pre-dispersion and coarse particle classification area 10 and the feeding and medium-coarse powder return connection area and the medium-coarse powder and fine powder classification area 58 can be used independently as two independent parts, and are arranged at different heights according to the process requirement. At this time, the medium-coarse powder return cone bucket 60 is not connected with the inside of the cage conical table 31, and the outer connection air pipe 9 is replaced by a non-standard connection air pipe 62. The air distribution and material distribution area and the pre-dispersion and coarse particle classification area 10 are located at the bottom and are connected with the medium-coarse powder and fine powder classification area 58 through the non-standard connection air pipe 62. The medium-coarse powder and fine powder classification area 58 is fixed on the platform of the process elevation through the support 59. The feeding pipe 8 is inserted into the inside of the non-standard connection air pipe 62 and extends to the middle axis, and then is connected with the built-in material pipe 61 which is vertically downward. The built-in material pipe 61 extends downward into the inside of the inner connection material pipe 7, and the built-in material pipe 61 and the inner connection material pipe 7 are sealed by the pipe sealing element 63. The built-in material pipe 61 is directly below the inner connection material pipe 7 and is provided with a rounded conical material scattering inverted cone 64, so as to uniformly distribute the material entering the inside of the cage conical table 31 and reduce the impact of the high-speed material flow caused by the height difference on the coarse particle separation rotating cage 51.

[0160] In addition, the feeding pipe 8 at the feeding position of the coarse and fine gradient classification powder machine can be cancelled, and is replaced by being connected in series with other static separation equipment or grinding equipment in a wind sweeping form to introduce a dust-containing air flow, so as to complete more stages of classification.

[0161] In order to further improve the classification clarity of coarse and fine particles, specifically, a ring-shaped "step" type dispersion device 70 (see Figure 12 ) or a ring-shaped "Z" type dispersion device 72 (see Figure 13). The dispersing plates 71 of the annular "ladder" shaped dispersing device 70 are all supported on the inner wall of the air inlet housing 27 by the support device 68, arranged in a ladder-shaped structure in a certain interval, and connected by connecting rib plates 69 between adjacent two dispersing plates 71. The dispersing plates 71 of the annular "Z" shaped dispersing device 72 are partly supported on the inner wall of the air inlet housing 27 by the support device 68, and partly supported on the outer wall of the flow guide cone 36 by the support device 68, and the dispersing plates 71 on both sides are arranged in a ladder-shaped structure in a certain interval, and the adjacent two dispersing plates 71 form a dispersing and grading channel corresponding to each other. The working principle is as follows: the material falling through the annular air ring 25 falls to the annular "ladder" shaped dispersing device 70 or the annular "Z" shaped dispersing device 72 under the action of gravity at a certain falling speed, is dispersed after being impacted by the corresponding dispersing plate 71, and is then blown and washed by the upward airflow between the dispersing plates 71, small particles pass through the annular air ring 25 upward into the coarse particle separation area for reseparation, and large particles leave the powder concentrator downward through the coarse particle outlet 28 into the coarse particle collection bin and return to the main grinding machine (roller press, vertical mill, etc.) for regrinding.

[0162] The working process of the above-mentioned classification method of the coarse-fine gradient classification powder concentrator is as follows:

[0163] The material to be sorted is fed into the pre-dispersion and coarse particle classification area inside the equipment by the feeding pipe 8 of the feeding and medium-coarse powder return connection area, dispersed onto the dispersion round steel 13 inside the coarse particle sorting rotating cage 51 under the action of the wear-resistant cap 15, and the material cake contained in the material is fully dispersed by the dispersion round steel 13. After being fully dispersed by the dispersion round steel 13, the material is distributed and uniformly thrown onto the material throwing table 34 by the lower rotating distribution disc cone 30 and the distribution disc bottom plate 24, then falls downward under the action of gravity with a certain kinetic energy to the annular air ring 25 of the air distribution area, and then collides with the air ring guide vane under the action of the falling kinetic energy and inertia, is fully dispersed again by the overlapped air ring guide vane 49, so that the fine particles (medium-coarse powder and fine powder) mixed between the “lumpy” material flow and the fine powder adhered to the surface of the coarse particles are fully dispersed and separated; the sorting air flow enters from the lower air inlet 47 of the air distribution area, is uniformly distributed under the joint action of the material guide cone 38, the air guide cone 36 and the air inlet shell 27, and then enters the annular air ring 25, concentrates and washes the material dispersed by the air ring guide vane at high speed, and completes the first coarse particle classification. Most of the coarse particles return to the material bed of the extrusion equipment to continue grinding under the action of gravity through the coarse particle outlet 28, and a small part of the coarse particles, most of the medium-coarse powder and fine powder pass through the annular air ring 25 upward with the sorting air flow to complete the second coarse and fine particle classification at the coarse particle sorting rotating cage 51. The coarse particle sorting rotating cage 51 rotates to form a forced vortex field, so that the coarse particles can be more accurately controlled not to pass through the coarse particle classification vane 21 to enter the subsequent classification process. The dust-containing air flow after sorting (passing through the coarse particle classification vane 21) enters the subsequent medium-coarse powder and fine powder classification area 58 upward along the dust-containing air flow upward channel between the inner connecting material pipe 7 and the outer connecting air pipe 9, and the fine classification device (guided by the static vane 4, and then rotated by the fine powder sorting rotating cage 3) is used to complete the fine classification of the medium-coarse powder and fine powder passing through the static vane 4. The sorted fine powder is collected as a finished product, the medium-coarse powder enters the fine grinding equipment for further grinding through the return control device 5, the medium-coarse powder return control valve 66 and the medium-coarse powder return pipe 6, or part of the medium-coarse powder returns to the pre-dispersion and coarse particle classification area below to be sorted again by adjusting the opening degree of the medium-coarse powder return control valve 66. The first is to solve the problem that the fine particles mixed in the medium-coarse powder in the upper fine powder classification area cannot be sorted out in time due to insufficient sorting clarity, improve the fine powder sorting efficiency, and the second is to adjust the material and load balance of the roller press loop and the ball mill loop of the combined / semi-finish grinding system, improve the grinding efficiency and reduce the system power consumption.

[0164] The process structure parameters of the application are as shown in the figure, and the following main process structure parameters are set for the design method of the application: Figures 14-16

[0165] The system design yield P (t / h), the material bulk density p s (t / m 3 ), and the material flow rate V​s (m / s), material filling rate ε = 0.5-0.8, system circulation load k, selected powder concentration C s (g / m 3 ), feeding concentration F s (kg / m 3 ), system selected powder air volume Q (m 3D1(mm), the height H1(mm) of the coarse particle sorting rotating cage 51, the diameter-height ratio D / H of the coarse particle sorting rotating cage 51, the outer diameter D2(mm) of the material distributing disc bottom plate 24, the diameter D3(mm) of the outer connecting air pipe 9, the diameter D4(mm) of the inner connecting material pipe 7, the diameter D5(mm) of the upper end of the inner cavity of the coarse particle sorting shell, the diameter D6(mm) of the inner ring 50 of the air ring, the diameter or the inner diameter D7(mm) of the air inlet shell 27 of the outer ring 48 of the air ring, the diameter D8(mm) of the interface of the guide cone 36 and the coarse material guide cone, the gap H2(mm) between the lower ring plate 22 and the material distributing disc bottom plate 24, the gap H3(mm) between the material distributing disc bottom plate 24 and the outlet of the annular air ring 25, the height H4(mm) of the annular air ring 25, the height H5(mm) of the material lifting platform 34, the vertical gap H6(mm) between the lower edge of the medium-coarse powder overflow hole 65 and the upper edge of the return material pipe interface 44, the vertical gap H7(mm) between the lower edge of the return material pipe interface 44 and the upper edge of the inner connecting material pipe 7, the diameter d2(mm) of the medium-coarse powder return material pipe 6, the number n1 of the medium-coarse powder return material pipes 6, the diameter d3(mm) of the medium-coarse powder overflow hole 65, the number n2 of the medium-coarse powder overflow holes 65, the angle θ1(°) between the inner ring 50 of the air ring and the horizontal direction, the number n3 of the air ring guide vanes 49, the thickness t(mm) of the air ring guide vanes 49, the angle θ2(°) between the air ring guide vanes 49 and the horizontal direction, the angle θ3(°) between the guide cone 36 and the horizontal direction, the angle θ4(°) between the material lifting platform 34 and the horizontal direction, the angle θ5(°) between the guide cone and the horizontal direction, the angle θ6(°) between the coarse particle sorting shell and the horizontal direction, the angle θ7(°) between the return material control device 5 and the horizontal direction, the angle θ8(°) between the line connecting the lower edge of the medium-coarse powder overflow hole 65 and the upper edge of the medium-coarse powder return cone 60 and the horizontal direction, the outlet wind speed V1(m / s) of the coarse particle sorting rotating cage 51, the radial wind speed V2(m / s) of the coarse particle sorting rotating cage 51, the outlet wind speed V3(m / s) of the annular air ring 25, the gap wind speed (the effective wind speed of the annular air ring 25) V4(m / s) of the air ring guide vanes 49, the lifting wind speed V5(m / s) of the air inlet 47, the blow washing wind speed V6(m / s) of the annular "ladder" shape scattering device, the blow washing wind speed V7(m / s) of the annular "Z" shape scattering device, the gap d1(mm) between the adjacent two air ring guide vanes 49, the horizontal projection length S2(mm) of the air ring guide vane 49, the horizontal projection overlapping length S1(mm) of the adjacent two air ring guide vanes 49, the gap (from top to bottom) d4(mm), d5(mm), d6(mm) between the adjacent two scattering plates of the annular "ladder" shape scattering device, the diameter (from top to bottom) D9(mm), D 10 (mm), D 11 (mm), D 12(mm), the adjacent two projection overlapping distance (from top to bottom) S3 (mm), S4 (mm), S5 (mm) of the adjacent two disintegrating plates of the annular "ladder" shaped disintegrating device, the gap (from top to bottom) d7 (mm), d8 (mm), d9 (mm) of the adjacent two disintegrating plates of the annular "Z" shaped disintegrating device, the lower end diameter (from top to bottom) D 13 (mm) of the disintegrating plates of the annular "ladder" shaped disintegrating device and the annular "Z" shaped disintegrating device. 14 (mm) of the disintegrating plates of the annular "ladder" shaped disintegrating device and the annular "Z" shaped disintegrating device. 15 (mm) of the disintegrating plates of the annular "ladder" shaped disintegrating device and the annular "Z" shaped disintegrating device. 16 (mm), the projection point distance S7 (mm), S8 (mm), S9 (mm) of the last end of the upper disintegrating plate of the annular "Z" shaped disintegrating device to the projection point on the next disintegrating plate, the included angle θ9 (°) of each disintegrating plate of the annular "ladder" shaped disintegrating device and the annular "Z" shaped disintegrating device to the horizontal direction.

[0166] The main process parameter calculation steps are as follows:

[0167] 1) The system selects the powder air volume Q (m 3 / h):

[0168] According to the system design yield P (t / h), the system cycle load k, the selected powder concentration C s (g / m 3 ), the feeding concentration F s (kg / m 3 ), the system selects the powder air volume Q (m 3 / h):

[0169]

[0170] Among them, the system cycle load k = 3 ± 1, the selected powder concentration C s = 800 ± 200 g / m 3 , the feeding concentration F s = 2.5 ± 0.5 kg / m 3 .

[0171] 2) The coarse particle separation rotating cage diameter D1 (mm):

[0172]

[0173] Among them, D / H = 1.8-2.0 is the diameter-height ratio of the coarse particle separation rotating cage, and V2 = 1.5-2.5 is the radial wind speed (m / s) of the coarse particle separation rotating cage;

[0174] 3) The coarse particle separation rotating cage height H1 (mm):

[0175]

[0176] 4) the outer diameter D2 (mm) of the center feeding cloth disc bottom plate:

[0177] D2 = D1 - (0~50) (4)

[0178] 5) the inner ring diameter D6 (mm) of the wind ring:

[0179] D6 = D2 - (40~60) (5)

[0180] 6) the outer ring diameter or the inner diameter D7 (mm) of the air inlet shell:

[0181]

[0182] wherein V3 = 10 ± 2 is the outlet wind speed (m / s) of the annular wind ring;

[0183] 7) the interface diameter D8 (mm) of the guide cone-coarse material guide cone:

[0184]

[0185] wherein V5 = 4 ± 1 is the inlet wind speed (m / s);

[0186] 8) the upper end diameter D5 (mm) of the coarse particle separation shell inner cavity:

[0187]

[0188] 9) the inner connecting pipe diameter D4 (mm):

[0189]

[0190] wherein the system circulation load k = 3 ± 1, the material bulk density ρ s = 1.5~1.8 (t / m 3 ), the material flow rate V s = 1 ± 0.5 (m / s), and the material filling rate ε = 0.5~0.8;

[0191] 10) the outer connecting pipe diameter D3 (mm):

[0192]

[0193] wherein V1 = 10~15 is the outlet wind speed (m / s) of the coarse particle separation rotating cage;

[0194] 11) the number n1 (pcs) of the medium-coarse powder return pipes and the number n2 (pcs) of the medium-coarse powder overflow holes:

[0195] n1 = n2 = 3 ± 1 (11)

[0196] 12) the diameter d2 (mm) of the medium-coarse powder return pipe:

[0197]

[0198] wherein, system cycle load k = 3 ± 1, material bulk density p s = 1.5 ~ 1.8 (t / m 3 ), material flow rate V s = 1 ± 0.5 (m / s), material filling rate ε = 0.5 ~ 0.8, and the number of medium-coarse powder return pipe n1 = 3 (pcs);

[0199] 13) Medium-coarse powder overflow hole diameter d3 (mm):

[0200] d3 = d2 (13)

[0201] 14) Gap H2 (mm) between lower ring plate and material distribution disc bottom plate:

[0202] H2 = 300 ± 50 (mm) (14)

[0203] 15) Gap H3 (mm) between material distribution disc bottom plate and annular air ring outlet:

[0204] H3 = 100 ± 50 (mm) (15)

[0205] 16) Number of air ring guide vane n3 (pcs):

[0206]

[0207] wherein, d1 is the gap between adjacent two air ring guide vanes, d1 = 100 ~ 200 (mm), V4 is the gap wind speed of air ring guide vane, V4 = 18 ± 2 (m / s), and n3 is the integer after rounding;

[0208] 17) Height H4 (mm) of annular air ring:

[0209]

[0210] wherein, θ2 = 40 ± 5 is the angle between air ring guide vane and horizontal direction (°), S1 / S2 = 0.3 ~ 0.8 is the ratio of the overlapping length of horizontal projection of adjacent two air ring guide vanes to the horizontal projection length of single air ring guide vane, and t = 10 ~ 20 is the thickness of air ring guide vane (mm);

[0211] 18) Height H5 (mm) of material lifting platform:

[0212] H5 = (1.2 ± 0.1) (H2 + H3) (18)

[0213] 19) Vertical gap H6 (mm) between the lower edge of medium-coarse powder overflow hole and the upper edge of return pipe interface:

[0214] H6 = 300 ± 50 (19)

[0215] 20) The vertical gap H7 (mm) between the lower edge of the material return pipe interface and the upper edge of the inner connecting pipe:

[0216] H7 = 200 ± 50 (20)

[0217] 21) The angle θ1 (°) between the inner ring of the air ring and the horizontal direction:

[0218] θ1 = 60 ± 10 (21)

[0219] 22) The angle θ3 (°) between the guide cone and the horizontal direction:

[0220] θ3 = 60 ± 10 (22)

[0221] 23) The angle θ4 (°) between the material lifting platform and the horizontal direction:

[0222] θ4 = 50 ± 5 (23)

[0223] 24) The angle θ5 (°) between the coarse material guide cone and the horizontal direction:

[0224] θ5 = 60 ± 5 (24)

[0225] 25) The angle θ6 (°) between the coarse particle sorting shell and the horizontal direction:

[0226] θ6 = 70 ± 5 (25)

[0227] 26) The angle θ7 (°) between the medium coarse powder guide cone and the horizontal direction:

[0228] θ7 = 65 ± 10 (26)

[0229] 27) The angle θ8 (°) between the lower edge of the medium coarse powder overflow hole and the upper edge of the medium coarse powder return cone bucket and the horizontal direction:

[0230] θ8 = 45 ± 10 (27)

[0231] 28) The diameter of the lower end of the ring-shaped "step" type scattering device, from top to bottom, respectively D9 (mm), D 10 (mm), D 11 (mm), D 12 (mm):

[0232]

[0233] D 12 = D8 + (500-600) (29)

[0234]

[0235]

[0236] 29) The gap between two adjacent plates of the annular "ladder" shaped dispersing device, from top to bottom, is d4 (mm), d5 (mm), d6 (mm), respectively:

[0237]

[0238] Wherein, V6 = 14 ± 2 is the annular "ladder" shaped dispersing device blow speed (m / s);

[0239] 30) The diameter of the lower end of the dispersing plate of the annular "Z" shaped dispersing device, from top to bottom, is D 13 (mm), D 14 (mm), D 15 (mm), D 16 (mm), respectively:

[0240]

[0241]

[0242] 31) The gap between two adjacent plates of the annular "Z" shaped dispersing device, from top to bottom, is d7 (mm), d8 (mm), d9 (mm), respectively:

[0243]

[0244]

[0245]

[0246] Wherein, V7 = 14 ± 2 is the annular "Z" shaped dispersing device blow speed (m / s);

[0247] 32) The overlapping distance of the projection of the generatrix of two adjacent plates of the annular "ladder" shaped dispersing device, from top to bottom, is S3 (mm), S4 (mm), S5 (mm), respectively:

[0248] S3 = S4 = S5 = 150 ± 50 (38)

[0249] If S3, S4, S5 cannot meet the requirements of formula (38), D9, D 10 , D 11 can be adjusted appropriately;

[0250] 33) The distance from the projection point of the end of the upper dispersing plate of the annular "Z" shaped dispersing device to the end of the lower dispersing plate, from top to bottom, is S7 (mm), S8 (mm), S9 (mm), respectively:

[0251] S7 = S8 = S9 = 150 ± 50 (39)

[0252] If S7, S8, S9 cannot meet the requirements of formula (39), D can be adjusted appropriately 14 , D 15 , D 16 calculated value;

[0253] 34) The included angle θ9(°) between each scattering plate of the annular "ladder" shaped scattering device and the annular "Z" shaped scattering device and the horizontal direction:

[0254] θ9 = 45 ± 5 (40).

[0255] To verify the technical effect of the present application, based on the TRPф400x100mm-ф750x2500mm semi-industrial combined grinding test system, a system powder selection air volume of 4000m 3 / h, a specification Cф300*550-Fф300-570mm coarse and fine gradient classification powder classifier, and the original V-type powder classifier of the system were used to conduct 40 sets of comparative test researches on grinding PO425 cement under the same basic working conditions, and the test statistical data results are shown in Table 1.

[0256] Table 1 Comparison of the powder classifier of the present application and the traditional V selection

[0257]

[0258] According to the data shown in Table 1, in terms of powder selection efficiency, compared with the traditional V selection technology, the present application has a significant decrease in the powder selection efficiency of particles with a particle size of >0.2mm under the same basic working conditions, with a cumulative decrease of 35.4%, and an increase of 20.9% in the powder selection efficiency of fine particles with a particle size of ≤0.2mm. The powder selection efficiency of coarse particles is reduced, more coarse particles return to the grinding equipment, the powder selection efficiency of ≤0.2mm small particles is increased, more finished particles leave the grinding equipment and do not return to the grinding equipment for regrinding, thereby destroying the stability of the material layer and reducing the grinding efficiency. Therefore, the powder selection clarity of the present application is greatly improved, solving the common problem of unclear separation of "coarse particles containing fine particles and fine particles containing coarse particles" in the traditional V selection, and achieving the expected purpose.

[0259] According to the test statistical data in Table 1, in terms of system performance efficiency, the system capacity per hour of the present application is increased from 1.51t / h to 1.78t / h, with an increase of 17.8%, and the specific surface area of the finished product is increased from 3183cm 2 / g to 3472cm 2 / g, the yield of finished product is improved significantly. In terms of the output of the main machine, the fines in the material of the roller press are reduced significantly due to the powder separation performance that the separation efficiency of particles with a size greater than 0.2 mm is reduced significantly and the separation efficiency of particles with a size less than 0.2 mm is increased, and the stability of the material layer is improved. The power absorbed by the roller press is increased from 17.9 kW to 21.4 kW, with an increase of 19.6%, and the output of the main machine is increased significantly, which provides an important guarantee for increasing the yield and reducing the consumption. In terms of the power consumption of the main machine, although the nominal power consumption is not significantly reduced, the equivalent power consumption is reduced from 21.1 kWh / t to 18.3 kWh / t at the same specific surface area of 3200 cm 2 / g, with a reduction of 13.2%.

[0260] In summary, compared with the conventional V separation technology, the effect of increasing the yield and reducing the consumption is significant.

[0261] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A coarse-fine gradient classifier, characterized in that: The coarse-fine gradient grading powder separator forms, from bottom to top, a wind distribution and material distribution area, a pre-dispersing and coarse particle grading area, a feeding and medium-coarse powder return connection area, and a medium-coarse powder and fine powder grading area. The wind distribution and material distribution area comprises an air inlet shell, an air inlet, a coarse particle outlet, a flow guide cone and a ring-shaped air ring, the air inlet is located on the side of the air inlet shell, the coarse particle outlet is located at the bottom of the air inlet shell, the flow guide cone is coaxially arranged inside the air inlet shell, and the ring-shaped air ring is installed above the outer edge of the flow guide cone and between the inner edge of the top of the air inlet shell; The pre-dispersing and coarse particle grading area comprises a coarse particle sorting shell, a coarse particle sorting rotating cage, a material distribution device and a coarse particle sorting drive, the coarse particle sorting rotating cage is located inside the coarse particle sorting shell, the coarse particle sorting rotating cage comprises coarse particle grading vanes located around, a cage conical frustum coaxially arranged inside the coarse particle grading vanes, and a dispersing round steel located on the inner side of the top of the cage conical frustum, the top of the coarse particle sorting rotating cage is provided with an upper ring plate, the middle part is provided with a middle ring plate, and the bottom is provided with a lower ring plate, the coarse particle grading vanes are located between the upper ring plate, the middle ring plate and the lower ring plate, and are close to the outer edges of the upper ring plate, the middle ring plate and the lower ring plate and are uniformly distributed in a radial manner; the upper part of the coarse particle sorting shell and the coarse particle grading vanes is provided with a support cover plate, the bottom surface of the support cover plate is fixedly connected with the coarse particle sorting shell, and the bottom surface of the support cover plate and the upper ring plate of the coarse particle sorting rotating cage are connected in a dynamic sealing manner to form the outer sealing of the rotating cage of the coarse particle sorting rotating cage; the support cover plate, the coarse particle sorting shell and the coarse particle grading vanes jointly form the coarse particle grading area; The material distribution device comprises a material distribution disc conical frustum and a material distribution disc bottom plate, the material distribution disc conical frustum is coaxially arranged below the cage conical frustum, the bottom end of the material distribution disc conical frustum is connected with the material distribution disc bottom plate, and the material distribution disc bottom plate and the lower ring plate form a material flow distribution channel; a material lifting platform is arranged between the coarse particle sorting shell and the air inlet shell, the material lifting platform is located on the outer side of the material flow distribution channel and is adjacent to the ring-shaped air ring on the lower side; the material distribution disc bottom plate and the inner ring of the ring-shaped air ring are connected in a dynamic sealing manner to form the dynamic sealing of the material distribution device; The coarse particle sorting drive is connected with the coarse particle sorting rotating cage and the material distribution disc conical frustum through a shaft system to drive the rotation of the coarse particle sorting rotating cage and the material distribution disc conical frustum; The feeding and medium-coarse powder return connection area and the medium-coarse powder and fine powder grading area comprise a feeding pipe, a medium-coarse powder return pipe and a fine grading device, the feeding pipe passes through the fine grading shell of the fine grading device and is connected with the inside of the cage conical frustum through an inner connecting pipe, the inner connecting pipe and the cage conical frustum are connected in a dynamic sealing manner to form the inner sealing of the rotating cage of the coarse particle sorting rotating cage; one end of the medium-coarse powder return pipe is connected with a medium-coarse powder return conical hopper of the fine grading device, and the other end passes out of the fine grading shell; the medium-coarse powder return conical hopper is connected with or not connected with the inside of the cage conical frustum, and the fine grading shell is connected with the support cover plate to form a dust-containing air flow rising channel.

2. The coarse-fine ladder classifier according to claim 1, wherein The feeding pipe is located directly above the center of the coarse particle sorting rotating cage, and the fine grading shell is connected with the support cover plate through an outer connecting air pipe. The outer edge of the cage cone is provided with a rotating cage inner sealing ring near the inner connecting pipe, and the rotating cage inner sealing ring cooperates with the inner connecting pipe to form a rotating cage inner sealing. The bottom surface of the support cover plate is fixedly connected with an outer sealing outer ring located outside the upper ring plate and an outer sealing inner ring located inside the upper ring plate, and the outer sealing outer ring and the outer sealing inner ring cooperate with the upper ring plate to form a rotating cage outer sealing. The bottom plate of the distributing disc is fixedly connected with a distributing device dynamic sealing outer ring on the outer edge of the bottom plate, and the inner ring of the annular air ring is provided with a distributing device dynamic sealing inner ring, and the distributing device dynamic sealing outer ring cooperates with the distributing device dynamic sealing inner ring to form a distributing device dynamic sealing.

3. The coarse-fine ladder classifier of claim 1, wherein The upper ring plate is connected with the cage cone through a rotating cage pull rod, the arrangement direction of the rotating cage pull rod is consistent with the rotating direction of the coarse particle separation rotating cage and is uniformly distributed along the axis of the coarse particle separation rotating cage, the inner edge of the lower ring plate is connected with the cage cone, and the inner edge of the middle ring plate is connected with the cage cone through a pull rod or a rib plate.

4. The coarse-fine ladder classifier of claim 1, wherein The feeding pipe at the feeding position of the coarse and fine gradient classification powder machine is cancelled and replaced with other static separation equipment or grinding equipment in series to introduce the dust-containing air flow in the form of air sweeping.

5. The coarse-fine ladder classifier of claim 1, wherein, The coarse particle separation rotating cage and the distributing disc cone are driven by the same drive, and the shaft system one includes a main shaft and a main shaft sleeve sleeved on the main shaft, the top of the main shaft is provided with a hub, the upper part of the hub is connected with the scattering round steel, the lower part of the hub is connected with the distributing disc cone, and the hub top is provided with a wear-resistant cap.

6. The coarse-fine ladder classifier of claim 1, wherein, The coarse particle separation rotating cage and the distributing disc cone are independently driven by two drives, and the coarse particle separation drive includes independent drive one and independent drive two, the shaft system one includes an inner transmission shaft and an outer transmission sleeve shaft, the upper end of the inner transmission shaft is connected with the scattering round steel through the hub, and the lower end is connected with the independent drive one, the outer transmission sleeve shaft is sleeved on the inner transmission shaft, the upper end of the outer transmission sleeve shaft is connected with the distributing disc cone, and the lower end is connected with the independent drive two through a belt pulley set.

7. The coarse-fine ladder classifier of claim 1, wherein The air distribution and distribution area and the pre-scattering and coarse particle classification area can be used independently as two parts, which are arranged at different heights according to process requirements, the middle-coarse powder return cone is not connected with the inside of the cage cone, the outer connecting air pipe is replaced with a non-standard connecting air pipe, and the air distribution and distribution area and the pre-scattering and coarse particle classification area are connected with the middle-coarse powder and fine powder classification area through the non-standard connecting air pipe.

8. The coarse-fine ladder classifier of claim 1, wherein, The air inlet is connected with a classification equipment or a grinding equipment, and the dust-containing air flow to be separated is introduced into the air inlet shell in the form of air sweeping.

9. The coarse-fine ladder classifier of claim 1, wherein, A ring-shaped "ladder" shaped scattering device or a ring-shaped "Z" shaped scattering device is arranged below the annular air ring and in the inner cavity of the air inlet shell. The dispersing plates of the circular "ladder" shaped dispersing device are arranged in a ladder structure with a certain interval, the overlapping distance of the bus bar projections of two adjacent dispersing plates is 100-200 mm, each dispersing plate is supported on the inner wall of the air inlet shell by a supporting device, and the dispersing plates are connected by connecting rib plates; The part of the dispersing plate of the annular "Z"-shaped dispersing device is supported on the inner wall of the air inlet shell by the supporting device, and the part of the dispersing plate is supported on the outer wall of the flow guide cone by the supporting device. The two sides of the dispersing plate are arranged in a stepped structure with a certain interval. The two adjacent dispersing plates on both sides form a dispersing and grading channel corresponding to each other. The projection point of the end of the previous dispersing plate on the next dispersing plate is 100-200 mm away from the end of the dispersing plate. The angle between each dispersing plate of the annular "ladder"-shaped dispersing device and the annular "Z"-shaped dispersing device and the horizontal direction is 40-50°. θ 9 10. The coarse-fine ladder classifier of claim 1, wherein, The annular air ring comprises an air ring inner ring, an air ring outer ring, and a plurality of air ring guide vanes obliquely arranged between the air ring inner ring and the air ring outer ring; the gap air speed of the air ring guide vanes is 18±2 m / s; the included angle between the air ring guide vanes and the horizontal direction is 35-45°; and the ratio S1:S2 of the overlapping length of the horizontal projection of two adjacent air ring guide vanes to the horizontal projection length of a single air ring guide vane is 0.3-0.

8. θ 2 is 35-45°; and the ratio S1:S2 of the overlapping length of the horizontal projection of two adjacent air ring guide vanes to the horizontal projection length of a single air ring guide vane is 0.3-0.

8.

11. The coarse-fine ladder classifier of claim 1, wherein, When the coarse particle separation rotating cage and the distributing device are driven by the same drive, the material flow distributing channel is uniformly distributed with distributing round steels, the top end of the distributing round steel is connected with the lower ring plate, and the bottom end is connected with the distributing disc bottom plate.

12. The coarse-fine ladder classifier of claim 1, wherein, The bottom end of the flow guide cone is connected with a coarse material guide cone.

13. The coarse-fine ladder classifier of claim 1, wherein, When the medium-coarse powder return cone hopper is in communication with the inside of the cage cone, a return control device is arranged in the medium-coarse powder return cone hopper, the return control device comprises a medium-coarse powder guide cone, a medium-coarse powder overflow hole is arranged on the medium-coarse powder guide cone, the return control device is in communication with the inside of the cage cone, an annular area for collecting medium-coarse powder is formed between the medium-coarse powder guide cone and the medium-coarse powder return cone hopper, a plurality of material distribution cones are uniformly arranged in the annular area in the circumferential direction, the material distribution cones are in a ridge shape formed by two plates being overlapped, the material distribution cones and the centrally-located medium-coarse powder guide cone divide the annular area into a plurality of funnel-shaped material areas, a return pipe interface is arranged at the bottom of each funnel-shaped material area, the return pipe interface is in a funnel shape with the upper part being large and the lower part being small, a medium-coarse powder return pipe is connected with the lower end of the return pipe interface, and a medium-coarse powder return control valve is arranged on the medium-coarse powder return pipe.

14. A classification method based on the coarse-fine gradient classification powder classifier according to any one of claims 1 to 13, characterized by, The material to be separated is fed into the pre-dispersing and coarse particle classification area inside the equipment by the feeding pipe of the feeding and medium-coarse powder return connection area, is dispersed onto the dispersing round steel inside the coarse particle separation rotating cage, is fully dispersed by the dispersing round steel, is distributed and uniformly thrown onto the lifting platform by the underside rotating distributing disc cone and the distributing disc bottom plate, and then falls at the annular air ring of the air distribution area, and is fully dispersed again by the air ring guide vane, so that the fine particles mixed in the material flow and the fine powder adhered to the surface of the coarse particles are fully dispersed and separated; the separation air flow enters from the air inlet, is uniformly distributed, and then enters the annular air ring, concentrates the material dispersed by the air ring guide vane, and completes the first coarse particle classification, most of the coarse particles return to the material bed of the extrusion equipment to continue grinding under the action of gravity, a small part of the coarse particles, most of the medium-coarse powder and the fine powder pass through the annular air ring upward along with the separation air flow, enter the coarse particle separation rotating cage to complete the second coarse and fine particle classification; the dust-containing air flow after separation enters the subsequent medium-coarse powder and fine powder classification area along the dust-containing air flow upward channel, and the fine classification device is used to complete the fine classification of the medium-coarse powder and the fine powder passing through the static vane, wherein the separated fine powder is collected as a finished product, the medium-coarse powder enters the fine grinding equipment for further grinding through the return control device, the medium-coarse powder return control valve and the medium-coarse powder return pipe; or, the medium-coarse powder returns to the pre-dispersing and coarse particle classification area below for secondary separation by adjusting the opening degree of the medium-coarse powder return control valve to make part of the medium-coarse powder pass through the medium-coarse powder overflow hole.

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