Raw material category screening equipment for roller mill

Abstract

The invention discloses raw material category screening equipment for a roller mill, and relates to the technical field of roller mills, the raw material category screening equipment comprises a roller milling bin and a millstone, the millstone is movably mounted at the bottom end of the roller milling bin, air supply outlets are uniformly formed in the bottom end of the roller milling bin, a plurality of milling roller mounting positions are formed in the bottom of the roller milling bin, and milling rollers are mounted in the milling roller mounting positions in a hinged mode; a coarse crushing unit is installed at the top of the roller grinding bin, a fine screening unit is installed below the coarse crushing unit, a coarse screening connecting pipe is installed between the coarse crushing unit and the fine screening unit, the fine screening unit is installed on the outer ring of the roller grinding bin, and a second discharging pipe is installed at the other end of the fine screening unit. The discharging end of the second discharging pipe penetrates through the roller grinding bin and extends to the inner side of the roller grinding bin, the discharging end of the second discharging pipe is located between every two adjacent grinding rollers, raw materials are preliminarily treated before being fed into the roller grinding bin, then the raw materials are screened, separated and fed in the feeding process, the raw material roller grinding efficiency is improved, and the raw material utilization rate is increased. And the abrasion of the grinding roller is indirectly reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of roller mills, and particularly relates to a raw material category screening device for a roller mill. BACKGROUND

[0002] A vertical roller mill, referred to as a vertical mill, is a kind of equipment for grinding cement raw materials, cement clinker, slag and coal ash, and has the characteristics of simple structure and low manufacturing and using cost. The vertical mill comprises a machine body, a grinding disc device and a transmission device. A centering structure for determining the center of rotation is arranged between the machine body and the grinding disc device. A rotating guide rail is fixedly arranged at the bottom of the grinding disc device. The grinding disc device is rotatably supported on the machine body through the rotating guide rail. The grinding disc device is in transmission connection with the transmission device. Since the transmission device does not bear the weight of the grinding disc and the high axial load such as the grinding pressure, the transmission device can adopt a general speed reducer, thereby having the advantages of compact structure configuration and reliable work, and the stop grinding time can be shortened and the use and maintenance cost of the equipment can be reduced.

[0003] In the existing vertical roller mill, the material is sent to the grinding disc, and the material is crushed by the grinding roller. In the use process, the grinding roller body and the wear-resistant lining plate are subjected to the combined action of forces such as the roller crushing force, the material reaction force, the frictional resistance between the material and the grinding roller lining plate, the shear stress of the grinding roller caused by the material crushing angle, the hydraulic system pressure of the roller mill and the apparent stress of the vertical mill. These forces all act on the effective crushing area of the vertical mill grinding roller. Once the matching gap appears, impact and collision will occur between the body and the lining plate, the wear between the body and the lining plate is aggravated, and in severe cases, cracks or even fractures will occur in the lining plate, causing the lining plate to fall off, the machine to be damaged, especially the damage to the speed reducer, and a vicious event will occur. Therefore, it is necessary to control the uniformity of the particle size of the raw material crushed by the grinding roller, so as to reduce the wear of the grinding roller. SUMMARY

[0004] In view of the above problems in the prior art, the purpose of the present application is to provide a raw material category screening device for a roller mill.

[0005] The present application provides the following technical solutions: A raw material category screening device for a roller mill, comprising a roller mill bin and a grinding disc, the grinding disc is movably installed at the bottom end of the roller mill bin, and a plurality of air supply openings are uniformly arranged at the bottom end of the roller mill bin, the air supply openings are arranged in the circumferential direction outside the outer circle of the grinding disc, the grinding disc is a centrifugal grinding disc, a plurality of grinding roller mounting positions are arranged at the bottom of the roller mill bin, grinding rollers are hingedly installed in the grinding roller mounting positions, a coarse crushing unit is installed at the top of the roller mill bin, a fine screening unit is installed below the coarse crushing unit, a coarse screening connecting pipe is installed between the coarse crushing unit and the fine screening unit, the fine screening unit is installed outside the outer circle of the roller mill bin, a second discharge pipe is installed at the other end of the fine screening unit, the discharge end of the second discharge pipe penetrates through the roller mill bin and extends to the inner side of the roller mill bin, and the discharge end of the second discharge pipe is located between two adjacent grinding rollers.

[0006] As a further technical solution, a first discharge pipe is installed below the coarse crushing unit, the discharge end of the first discharge pipe passes through the roller mill bin and extends to the inside of the roller mill bin, the discharge end of the first discharge pipe is located between two adjacent mill rollers, and the coarse screen connecting pipe is installed at the bottom end of the first discharge pipe.

[0007] As a further technical solution, a plurality of rib plates are installed at the bottom end of the roller mill bin, a transmission device is installed at the bottom end of the mill disc, and the transmission device is located between the plurality of rib plates.

[0008] As a further technical solution, the top of the roller mill bin is open, a top support body is installed at the top opening of the roller mill bin, the coarse screen unit is installed on the mounting seat, one side of the mounting seat is connected with the top support body, the inside of the top support body is hollow, a separator is installed in the top support body, a top cover is installed on the top of the separator, and a discharge port is installed on the top cover.

[0009] As a further technical solution, an arc-shaped hole is formed in the top support body, and a transparent plate is installed in the arc-shaped hole.

[0010] As a further technical solution, the coarse crushing unit is provided with a coarse crushing cavity, a plurality of coarse crushing rollers are movably installed in the coarse crushing cavity, a shaft coupling is installed at one end of the coarse crushing roller, the shaft coupling is movably connected with the coarse crushing unit, an electric motor is installed at the other end of the shaft coupling, the electric motor is located outside the coarse crushing unit, an upper opening and a lower opening are formed in the coarse crushing unit, the upper opening is located above the coarse crushing cavity, the lower opening is located below the coarse crushing cavity, and a feeding hopper is installed at the upper opening.

[0011] As a further technical solution, a feeding port and a discharging port are formed in the first discharge pipe, the lower opening is connected with the feeding port, a grid sieve plate is installed on the feeding section of the first discharge pipe, and the discharging port is connected with the coarse screen connecting pipe.

[0012] As a further technical solution, a brush roller is further installed on the feeding section of the first discharge pipe, the brush roller is located above the grid sieve plate, a sliding groove is formed in the first discharge pipe, one end of the brush roller extends to the outside of the first discharge pipe through the sliding groove, one end of the brush roller is connected with a servo motor, the servo motor is installed on a sliding plate, the sliding plate is slidably connected with the sliding groove, a pneumatic cylinder is installed on one side of the first discharge pipe, and one end of the pneumatic cylinder is connected with the sliding plate.

[0013] As a further technical solution, an opening and closing plate is installed at the junction between the feeding section of the first discharge pipe and the middle inclined section of the first discharge pipe, the opening and closing plate is electrically driven and is coupled and connected with the control system of the roller mill.

[0014] As a further technical scheme, the fine screening unit is internally provided with a plurality of layers of screen plates, the plurality of layers of screen plates are distributed in an up-down manner, and the screen plates are all installed in an inclined manner, wherein one end of the screen plate adjacent to the second discharge pipe is lower in height than the other end.

[0015] The present application has the following beneficial effects: The raw material first passes through the coarse crushing unit for preliminary crushing treatment before entering the roller mill bin, so that the particle size of the raw material first falling on the grinding disc is reduced, the wear of the grinding roller is reduced, and the efficiency of the grinding roller is improved. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, illustrate the present application together with the embodiments thereof, and explain the present application, but do not constitute a limitation of the present application. In the drawings: Figure 1 is a schematic view of the shaft side structure of the present application; Figure 2 is a schematic view of the shaft side structure of the second discharge pipe installation position of the present application; Figure 3 is a schematic view of the internal structure of the coarse crushing unit of the present application; Figure 4 is a schematic view of the main view structure of the first discharge pipe of the present application; Figure 5 is a schematic view of the right view cross-sectional structure of the first discharge pipe of the present application.

[0017] Marked in the figure: 1, separator; 2, top support; 3, top cover; 301, discharge port; 4, roller mill bin; 401, mill roller mounting position; 402, air supply port; 403, transmission device; 7, coarse screen connecting pipe; 8, grinding disc; 5, coarse crushing unit; 501, feeding hopper; 502, mounting seat; 503, first discharge pipe; 504, coarse crushing roller; 505, coarse crushing cavity; 506, shaft coupling; 507, motor; 508, motor bracket; 509, opening and closing plate; 510, sliding plate; 511, servo motor; 512, chute; 513, air cylinder; 514, brush roller; 515, grid sieve plate; 516, discharge port; 517, feeding port; 518, upper opening; 519, lower opening; 6, fine screening unit; 601, second discharge pipe. DETAILED DESCRIPTION

[0018] As Figure 1 shown, the application provides a raw material category screening device for a roller mill, which comprises a roller mill bin 4 and a grinding disc 8, the grinding disc 8 is movably installed at the bottom end of the roller mill bin 4, a plurality of rib plates 402 are installed at the bottom end of the roller mill bin 4, a transmission device 403 is installed at the bottom end of the grinding disc 8, the transmission device 403 is located between the plurality of rib plates 402, a plurality of air supply ports 402 are uniformly provided at the bottom end of the roller mill bin 4, the plurality of air supply ports 402 are arranged in the circumferential direction of the outer ring of the grinding disc 8, the grinding disc 8 is a centrifugal grinding disc, a mill roller mounting position 401 is provided at the bottom of the roller mill bin 4, the top of the roller mill bin 4 is open, a top support 2 is installed at the top opening of the roller mill bin 4, the inside of the top support 2 is hollow, a separator 1 is installed in the top support 2, a top cover 3 is installed on the top of the separator 1, a discharge port 301 is installed on the top cover 3, in actual use, in order to facilitate better discharge, the discharge port 301 can be connected with a discharge air pipe, an arc-shaped hole 201 is provided on the top support 2, a transparent plate is installed in the arc-shaped hole 201, so as to observe the working condition of the separator 1.

[0019] Preferably, the mill roller mounting position 401 is three or four, at this time, the size of the mill roller and the distance between adjacent mill rollers are optimal, which facilitates the raw material to pass through the mill roller immediately after entering, in addition, the mill roller is hingedly installed in the mill roller mounting position 401, so as to facilitate regular maintenance of the mill roller.

[0020] In operation, the grinding disc 8 is driven to rotate by the transmission device 403, the material falls on the grinding disc 8 through the feeding structure, the hot air provided by the external fan of the device enters the roller mill bin 4 through the air supply port 402, with the rotation of the grinding disc 8, the material moves to the edge of the grinding disc 8 under the action of centrifugal force, is crushed by the mill roller when passing through the annular groove on the grinding disc 8, after crushing, the material is taken up by the high-speed airflow of the air ring at the edge of the grinding disc 8, the large particles directly fall on the grinding disc 8 for regrinding, the material in the airflow falls into the grinding disc 8 for regrinding under the action of the rotating rotor when passing through the upper separator 1, the qualified fine powder is discharged from the discharge port 301 together with the airflow.

[0021] In this process, the moisture-containing material is dried in contact with the hot gas stream, and for different humidity requirements, the temperature of the hot air can be adjusted to meet the requirements, and the size of the material is adjusted by the separator. The above is the prior art, which will not be described here.

[0022] Example one As shown in Figure 1 and Figure 3 The top of the roller mill bin 4 is provided with a coarse crushing unit 5, the coarse crushing unit 5 is installed on a mounting seat 502, one side and the top of the mounting seat 502 is connected with the support body 2, and the first discharge pipe 503 is installed below the coarse crushing unit 5, the discharge end of the first discharge pipe 503 penetrates through the roller mill bin 4 and extends to the inner side thereof, and the discharge end of the first discharge pipe 503 is located between two adjacent grinding rollers, and the coarse crushing connecting pipe 7 is installed at the bottom end of the first discharge pipe 503. After the raw material passes through the coarse crushing unit 5, it enters the grinding disc 8, and the raw material is preliminarily treated by the coarse crushing unit, so that the particle size of the raw material falling on the grinding disc 8 is reduced, thereby reducing the wear of the grinding roller, and the grinding efficiency is also relatively improved.

[0023] Specifically, the coarse crushing unit 5 is provided with a coarse crushing cavity 505, a plurality of coarse crushing rollers 504 are movably installed in the coarse crushing cavity 505, and the raw material is crushed by the plurality of coarse crushing rollers 504. One end of the coarse crushing roller 504 is provided with a shaft coupling 506, the shaft coupling 506 is movably connected with the coarse crushing unit 5, the other end of the shaft coupling 506 is provided with a motor 507, and the motor 507 is located outside the coarse crushing unit 5. The motor 507 serves as a power unit of the coarse crushing roller 504, and when working, the motor 507 drives the coarse crushing roller 504 to rotate, and the coarse crushing unit 5 is provided with an upper opening 518 and a lower opening 519, the upper opening 518 is located above the coarse crushing cavity 505, the upper opening 518 is provided with a feeding hopper 501, and the lower opening 519 is located below the coarse crushing cavity 505. The lower opening 519 is communicated with the first discharge pipe 503.

[0024] In order to further feed, the feeding hopper 501 is installed to adjust the speed of the raw material entering the coarse crushing unit 5, so that the working efficiency of the coarse crushing unit 5 is optimal. Specifically, the raw material is put into the feeding hopper 501, the motor 507 drives the coarse crushing roller 504 to rotate, and the coarse crushing roller 504 preliminarily crushes the raw material, and the crushed raw material enters the first discharge pipe 503 through the lower opening 519 and falls on the grinding disc 8 through the first discharge pipe 503.

[0025] Example two Based on the above example one, as shown in Figure 1 and Figure 2As shown, the coarse crushing unit 5 is installed below the fine screening unit 6, and the coarse screening connecting pipe 7 is installed between the coarse crushing unit 5 and the fine screening unit 6, the coarse screening connecting pipe 7 is connected to the bottom end of the first discharge pipe 503, the fine screening unit 6 is installed on the outer ring of the roller mill bin 4, and the second discharge pipe 601 is installed at the other end of the fine screening unit 6, the discharge end of the second discharge pipe 601 penetrates through the roller mill bin 4 and extends to the inner side of the roller mill bin 4, and the discharge end of the second discharge pipe 601 is located between two adjacent grinding rollers.

[0026] Specifically, after the raw material is coarsely screened by the coarse screening unit 5, part of the raw material falls on the grinding disc 8 through the first discharge pipe 503, and the other part falls into the fine screening unit 6 through the coarse screening connecting pipe 7, the fine screening unit 6 is installed with multiple layers of sieve plates, the multiple layers of sieve plates are distributed up and down, and the sieve plates are all installed obliquely, wherein the height of one end of the sieve plate adjacent to the second discharge pipe 601 is lower than the height of the other end, and the fine screening unit 6 has a vibrating function, therefore, the raw material falling into the fine screening unit 6 is vibrated by external force and falls down in turn until it falls on the grinding disc 8 through the second discharge pipe 601.

[0027] Referring to Figure 1 It can be seen that the position of the first discharge pipe 503 and the position of the second discharge pipe 601 are arranged oppositely, the purpose of this arrangement is that the particles of the raw material passing through the fine screening unit 6 are relatively small, therefore, after the raw material falling on the grinding disc 8 through the second discharge pipe 601, when the grinding disc 8 rotates by nearly 180°, the raw material is crushed by the grinding roller, and the crushed material is lifted by the high-speed airflow of the air ring at the edge of the grinding disc, and then is discharged from the discharge port 301 of the separator 1, that is, the roller milling is completed before the raw material reaches the position below the first discharge pipe 503, and the particles of the raw material falling on the grinding disc 8 through the coarse crushing unit 5 and the first discharge pipe 503 are relatively large, therefore, when the particles are similar to the particles passing through the fine screening unit 6 after the grinding disc 8 rotates by nearly 180°, the particles are crushed by the grinding roller after the grinding disc 8 rotates by nearly 180° again, and the crushed material is lifted by the high-speed airflow of the air ring at the edge of the grinding disc, and then is discharged from the discharge port 301 of the separator 1, therefore, the uneven size of the particles of the raw material encountered during the grinding roller crushing process is reduced, and the serious wear of the grinding roller is avoided.

[0028] Example Three Based on the above-mentioned example two, as shown in Figure 4 and Figure 5 The first discharge pipe 503 is provided with an inlet 517 and a discharge opening 516, the discharge opening 519 is connected to the inlet 517, and the inlet section of the first discharge pipe 503 is provided with a grid sieve plate 515, and the discharge opening 516 is connected to the coarse screening connecting pipe 7, the purpose of arranging the grid sieve plate 515 is to screen out the raw material with large particles passing through the coarse crushing unit 5, so that the raw material can smoothly enter the first discharge pipe 503.

[0029] Further, as shown in Figure 1As shown, the first discharge pipe 503 comprises a feeding section, an intermediate inclined section and a discharge section, as shown in the figure Figure 4 and Figure 5 As shown, the feeding section of the first discharge pipe 503 is also provided with a brush roller 514, which is located above the grid sieve plate 515. The raw material preliminarily crushed by the coarse crushing unit 5 falls on the grid sieve plate 515 through the feeding port 517. The brush roller 514 reciprocates relative to the grid sieve plate 515, which aims to smoothly push the raw material from the grid sieve plate 515 of the first discharge pipe 503 into the intermediate inclined section, and further screen the raw material on the grid sieve plate 515 by external force, so that it falls below the grid sieve plate 515 and smoothly enters the coarse screen connecting pipe 7 through the discharge port 516, and then enters the roller mill bin 4 from the second discharge pipe 601 after being screened by the fine screening unit 6.

[0030] Specifically, the first discharge pipe 503 is provided with a sliding groove 512, one end of the brush roller 514 extends to the outside of the first discharge pipe 503 through the sliding groove 512, and one end of the brush roller 514 is connected with a servo motor 511. The servo motor 511 is installed on a sliding plate 510, and the sliding plate 510 and the sliding groove 512 are slidingly connected. One side of the first discharge pipe 503 is provided with a pneumatic cylinder 513, one end of the pneumatic cylinder 513 is connected with the sliding plate 510. During operation, the reciprocating motion of the brush roller 514 is realized by the pneumatic cylinder 513, and the servo motor 511 drives the brush roller 514 to rotate.

[0031] Further, the feeding section of the first discharge pipe 503 and the intermediate inclined section of the first discharge pipe 503 are provided with an opening and closing plate 509. The opening and closing plate 509 is electrically driven and is coupled with the control system of the roller mill. In order to avoid that the raw material falls into the intermediate inclined section without being screened by the grid sieve plate 515, the electric opening and closing plate 509 is arranged between the feeding section and the intermediate inclined section of the first discharge pipe 503. According to the working efficiency of the brush roller 514, the intermittent opening and closing of the opening and closing plate 509 is set by program, so as to filter the raw material to the maximum extent.

[0032] The working principle of the present application is as follows: The grinding disc 8 is driven to rotate by the transmission device 403, and the material falls on the grinding disc 8 through the feeding structure, After the raw materials are coarsely sieved by the coarse sieving unit 5, the opening and closing plate 509 is in the closed state, the servo motor 511 drives the brush roller 514 to rotate, the cylinder 513 makes the brush roller 514 reciprocate, and the opening and closing plate 509 is opened. At this time, part of the raw materials falls on the grinding disc 8 through the first discharge pipe 503, and the other part falls in the fine sieving unit 6 through the coarse sieving connecting pipe 7. The raw materials fall on the grinding disc 8 through the second discharge pipe 601 by the vibration work of the fine sieving unit 6. The raw materials falling on the grinding disc 8 through the first discharge pipe 503 and the raw materials falling on the grinding disc 8 through the second discharge pipe 601 coincide after the grinding disc rotates 180 degrees. When the grinding disc rotates again by no more than 180 degrees, the device is connected with an external fan, hot air provided by the fan enters the roller mill bin 4 through the air supply port 402. With the rotation of the grinding disc 8, the materials move to the edge of the grinding disc 8 under the action of centrifugal force, are crushed by the grinding roller when passing through the annular groove on the grinding disc 8, and are carried by the high-speed airflow of the air ring after being crushed. The materials in the airflow pass through the upper separator 1, and under the action of the rotating rotor, the coarse powder falls from the hopper to the grinding disc 8 for regrinding, and the qualified fine powder is discharged from the discharge port 301 together with the airflow.

[0033] The above are only preferred embodiments of the present application and are not used to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can modify the technical solutions recorded in the foregoing embodiments or make equivalent replacements to some technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A raw material category screening device for a roller mill, comprising a roller mill bin (4) and a grinding disc (8), the grinding disc (8) being movably mounted at the bottom end of the roller mill bin (4), and the bottom end of the roller mill bin (4) being uniformly provided with air supply openings (402), a plurality of the air supply openings (402) being arranged in the circumferential direction outside the outer ring of the grinding disc (8), and the grinding disc (8) being a centrifugal grinding disc, characterized in that, The roller mill bin (4) is provided with a plurality of grinding roller mounting positions (401) at the bottom, grinding rollers are hingedly mounted in the grinding roller mounting positions (401), a coarse crushing unit (5) is mounted at the top of the roller mill bin (4), a fine screening unit (6) is mounted below the coarse crushing unit (5), a coarse screening connecting pipe (7) is mounted between the coarse crushing unit (5) and the fine screening unit (6), the fine screening unit (6) is mounted on the outer ring of the roller mill bin (4), a second discharge pipe (601) is mounted at the other end of the fine screening unit (6), the discharge end of the second discharge pipe (601) penetrates through the roller mill bin (4) and extends to the inner side thereof, and the discharge end of the second discharge pipe (601) is located between two adjacent grinding rollers.

2. The raw material category screening apparatus for a roll mill according to claim 1, characterized by, A first discharge pipe (503) is mounted below the coarse crushing unit (5), the discharge end of the first discharge pipe (503) penetrates through the roller mill bin (4) and extends to the inner side thereof, the discharge end of the first discharge pipe (503) is located between two adjacent grinding rollers, and the coarse screening connecting pipe (7) is mounted at the bottom end of the first discharge pipe (503).

3. The raw material category screening apparatus for a roll mill according to claim 1 or 2, characterized by, A plurality of rib plates (402) are mounted at the bottom end of the roller mill bin (4), a transmission device (403) is mounted at the bottom end of the grinding disc (8), and the transmission device (403) is located between the plurality of rib plates (402).

4. The raw material category screening apparatus for a roll mill according to claim 3, characterized by, The top of the roller mill bin (4) is open, a top support body (2) is mounted at the top opening of the roller mill bin (4), the coarse screening unit (5) is mounted on a mounting seat (502), one side of the mounting seat (502) is connected with the top support body (2), the inside of the top support body (2) is hollow, a separator (1) is mounted in the top support body (2), a top cover (3) is mounted on the top of the separator (1), and a discharge port (301) is mounted on the top cover (3).

5. The raw material category screening apparatus for a roll mill according to claim 4, characterized by, An arc-shaped hole (201) is formed in the top support body (2), and a transparent plate is mounted in the arc-shaped hole (201).

6. The raw material category screening apparatus for a roll mill according to claim 2, characterized by, The coarse crushing unit (5) is provided with a coarse crushing cavity (505), a plurality of coarse crushing rollers (504) are movably mounted in the coarse crushing cavity (505), a shaft coupling (506) is mounted at one end of the coarse crushing roller (504), the shaft coupling (506) is movably connected with the coarse crushing unit (5), a motor (507) is mounted at the other end of the shaft coupling (506), the motor (507) is located outside the coarse crushing unit (5), an upper opening (518) and a lower opening (519) are formed in the coarse crushing unit (5), the upper opening (518) is located above the coarse crushing cavity (505), the lower opening (519) is located below the coarse crushing cavity (505), and a feeding hopper (501) is mounted at the upper opening (518).

7. The raw material category screening apparatus for a roll mill according to claim 6, characterized by, A feeding port (517) and a discharging port (516) are formed in the first discharge pipe (503), the lower opening (519) is connected with the feeding port (517), a grid sieve plate (515) is mounted on the feeding section of the first discharge pipe (503), and the discharging port (516) is connected with the coarse screening connecting pipe (7).

8. The raw material category screening apparatus for a roll mill according to claim 7, characterized by, The feeding section of the first discharge pipe (503) is further provided with a brush roller (514) located above the grid sieve plate (515). A sliding groove (512) is formed in the first discharge pipe (503), and one end of the brush roller (514) extends to the outside of the first discharge pipe (503) through the sliding groove (512). One end of the brush roller (514) is connected with a servo motor (511), and the servo motor (511) is mounted on a sliding plate (510). The sliding plate (510) is in sliding connection with the sliding groove (512). One side of the first discharge pipe (503) is provided with a pneumatic cylinder (513), and one end of the pneumatic cylinder (513) is connected with the sliding plate (510).

9. The raw material category screening apparatus for a roll mill according to claim 8, characterized by, An opening and closing plate (509) is mounted at the junction of the feeding section of the first discharge pipe (503) and the middle inclined section of the first discharge pipe (503). The opening and closing plate (509) is electrically driven and is coupled with the control system of the roller mill.

10. The raw material category screening apparatus for a roll mill according to claim 1, characterized by, The fine screening unit (6) is provided with multiple layers of sieve plates, which are arranged in an up-down distribution and are all installed in an inclined manner. The sieve plate adjacent to the second discharge pipe (601) has one end lower than the other end in height.

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