A rapeseed screening apparatus

Abstract

The application provides rapeseed screening equipment and relates to rapeseed screening technology, which comprises a screening bin, a square column coaxially arranged in the screening bin, a rotating tube coaxially and slidably arranged on the square column, screening frames connected to both sides of the rotating tube, the screening frames being arranged in a central symmetry around the central axis of the rotating tube, screens arranged in the screening frames, rotating plates coaxially connected to both ends of the rotating tube, and the opposite surfaces of the two rotating plates being connected to the screening frames; a feeding bin arranged on the upper part of one end of the screening bin and communicating with the screening bin, the feeding bin being provided with a first channel bin; a discharging bin arranged on the lower part of one end of the screening bin and communicating with the screening bin, the communicating part of the discharging bin and the screening bin being provided with a screening plate, the screening plate being in an arc shape coaxial with the screening bin and the inner arc surface of the screening plate matching the radius of the inner wall of the screening bin; and a slag discharging bin arranged on the lower part of the other end of the screening bin and communicating with the screening bin. The application does not need manual impurity cleaning and improves the screening efficiency, and has strong practicability.

Description

Technical Field

[0001] This application relates to rapeseed screening technology, specifically to a rapeseed screening device. Background Technology

[0002] When processing rapeseed into rapeseed oil, the rapeseed raw material contains impurities such as roots, stems, leaves, and husks. Therefore, it is necessary to screen the rapeseed raw material to select the effective rapeseed and then screen out the excess impurities for use as feed or fertilizer.

[0003] Currently, in rapeseed oil processing production lines, the rapeseed raw material is generally screened using a vibrating screen. The rapeseed raw material is placed on the vibrating screen, and the screen is driven by a vibrating motor to vibrate, causing the rapeseed to pass through the screen, while the impurities are separated and remain on the screen. However, this screening method requires manual cleaning of impurities from the screen, which is quite troublesome. In addition, the amount screened at one time is small, resulting in low screening efficiency. Summary of the Invention

[0004] To address the aforementioned deficiencies in the existing technology, this application provides a rapeseed screening device that eliminates the need for manual cleaning of impurities, improves screening efficiency, and has strong practicality.

[0005] To achieve the above objectives, the present invention employs the following techniques:

[0006] A rapeseed screening device includes:

[0007] The screening chamber contains a square column that rotates coaxially inside. A rotating tube is slidably fitted onto the square column. Screening frames are connected to both sides of the rotating tube. The screening frames are symmetrically arranged around the central axis of the rotating tube. Each screening frame contains a screen. The side of the screening frame away from the rotating tube slides in contact with the inner wall of the screening chamber. Rotating plates are coaxially connected to both ends of the rotating tube. The opposing surfaces of the two rotating plates are connected to the screening frames, and the sides of the rotating plates slide in contact with the inner wall of the screening chamber.

[0008] The feeding hopper is located at the upper part of one end of the screening hopper and is connected to it. The feeding hopper is connected to the first channel hopper.

[0009] The discharge hopper is located at the lower end of one end of the screening hopper and is connected to it. A screening plate is provided at the connection between the discharge hopper and the screening hopper. The screening plate is in the shape of an arc coaxial with the screening hopper and its inner arc surface matches the radius of the inner wall of the screening hopper. The length of the screening plate along the axial direction of the screening hopper matches the length of the rotating tube.

[0010] The slag discharge bin is located at the lower part of the other end of the screening bin and is connected to it. The length of the connection between the slag discharge bin and the screening bin along the axial direction of the screening bin matches the length of the rotating pipe.

[0011] The beneficial effects of this invention are as follows:

[0012] By setting up a screening chamber and a movable rotating plate, rapeseed can be screened into the discharge chamber, and impurities can be screened into the slag discharge chamber, eliminating the need for manual cleaning of impurities. Furthermore, by setting up a two-stage screening system with a screen and a screening plate, the screening pressure can be reduced and the screening efficiency can be improved. Attached Figure Description

[0013] Figure 1 This is a three-dimensional schematic diagram of the rapeseed screening device according to an embodiment of this application.

[0014] Figure 2 This is a schematic diagram of the internal structure of the screening chamber in an embodiment of this application.

[0015] Figure 3 This is a schematic diagram of the driving structure of the square column according to an embodiment of this application.

[0016] Figure 4 This application Figure 3 A magnified view of a portion of point A in the middle.

[0017] Figure 5 This is a schematic diagram of the drive of the electric lead screw according to an embodiment of this application.

[0018] Figure 6 This is a schematic diagram of the internal structure of the receiving bin in an embodiment of this application.

[0019] Figure 7 This is an exploded structural diagram of the screening chamber, the annular track, and the annular plate in an embodiment of this application.

[0020] Figure 8 This is a schematic diagram showing the position of the arc-shaped strip on the annular plate according to an embodiment of this application.

[0021] Figure 9 This is a three-dimensional schematic diagram of the rapeseed screening device according to an embodiment of this application from another perspective.

[0022] The diagram shows the following components: 1-screening chamber, 11-square column, 12-rotating tube, 13-screening frame, 14-screen mesh, 15-rotating plate, 16-bearing seat, 17-drive column, 18-rotating mechanism, 19-rotating seat, 110-cam, 111-electric lead screw, 112-drive block, 113-drive rod, 114-drive wheel, 115-fitting ring, 116-annular groove, 117-air outlet pipe, 118-air outlet, 119-dust suction pipe, 120-annular track, 121-arc strip, 122-annular plate, 123-fixed hook, 1 24-Ring strip, 125-Ventilation pipe, 126-Limiting rod, 127-Limiting sleeve, 2-Feeding bin, 21-First channel bin, 22-Baffle bin, 23-Baffle, 24-Second channel bin, 25-Opening, 26-Sliding rod, 27-Matching block, 28-Sliding channel, 29-Mounting frame, 210-Screw, 211-Lifting block, 212-Rotating head, 3-Discharge bin, 31-Screwing plate, 4-Slag discharge bin, 5-Receiving bin, 51-Discharge hopper, 6-Bearing rod, 61-Bearing frame, 62-First bearing plate, 63-Second bearing plate. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the implementation methods of the present invention will be described in detail below with reference to the accompanying drawings. However, the embodiments described in this invention are only some embodiments of the present invention, and not all embodiments.

[0024] like Figure 1 As shown in the figure, this embodiment provides a rapeseed screening device, including a screening chamber 1, a feeding chamber 2, a discharging chamber 3, and a slag discharge chamber 4.

[0025] Specifically, such as Figure 2 As shown, a square column 11 is coaxially rotatable inside the screening chamber 1. A rotating tube 12 is coaxially slidably fitted onto the square column 11. Screening frames 13 are connected to both sides of the rotating tube 12. The screening frames 13 are symmetrically arranged around the central axis of the rotating tube 12. Each screening frame 13 is equipped with a screen 14, which is used to screen out rapeseed and small impurities. The side of the screening frame 13 away from the rotating tube 12 is in sliding contact with the inner wall of the screening chamber 1. Rotating plates 15 are coaxially connected to both ends of the rotating tube 12. The opposing surfaces of the two rotating plates 15 are connected to the screening frames 13, and the sides of the rotating plates 15 are in sliding contact with the inner wall of the screening chamber 1.

[0026] Specifically, such as Figure 1 and Figure 2 As shown, the feed bin 2 is located at the upper part of one end of the screening bin 1 and is connected to it. The feed bin 2 is connected to the first channel bin 21, which is used to receive rapeseed to be screened from the outside.

[0027] Specifically, such as Figure 2As shown, the discharge bin 3 is located at the lower end of the screening bin 1 and is connected to it. A screening plate 31 is provided at the connection between the discharge bin 3 and the screening bin 1. More specifically, the screening plate 31 has multiple screening holes for screening out rapeseed. The screening plate 31 is arc-shaped and coaxial with the screening bin 1, and its inner arc surface matches the radius of the inner wall of the screening bin 1. The length of the screening plate 31 along the axial direction of the screening bin 1 matches the length of the rotating tube 12, so that when the rotating tube 12 slides on the square column 11 to a certain position, the screening plate 31 is located between two rotating plates 15. The discharge bin 3 is used to receive the rapeseed that is finally screened out and send it to the next process.

[0028] Specifically, such as Figure 1 and Figure 2 As shown, the slag discharge bin 4 is located at the lower part of the other end of the screening bin 1 and is connected to it. The length of the connection between the slag discharge bin 4 and the screening bin 1 along the axial direction of the screening bin 1 matches the length of the rotating tube 12. This is so that when the rotating tube 12 slides on the square column 11 to a certain position, the connection between the slag discharge bin 4 and the screening bin 1 is located between the two rotating plates 15. The slag discharge bin 4 is used to receive the impurities that are finally screened out and send them to the next process.

[0029] During operation, first move the rotating tube 12 so that the screening plate 31 is positioned between the two rotating plates 15. Rotate the square column 11, which drives the rotating tube 12 to rotate, so that both screening frames 13 are in a horizontal position. Rapeseed to be screened is fed into the first channel chamber 21. The rapeseed passes through the first channel chamber 21 into the feed chamber 2 and falls into the screening chamber 1, landing above the screen 14. At this point, the screen 14 performs the first screening. The screened rapeseed and small impurities enter below the screen 14 and then undergo a second screening via the screening plate 31. The screened rapeseed enters the discharge chamber 3. The process continues until the screen 15 is fully operational. The movable square column 11 causes the screening plate 31 to flip, and the rapeseed that was not screened out by the screening plate 31 and the smaller impurities are screened again above the screen 14. The flipping also disturbs the rapeseed, making it easier to screen again. After the screen 14 flips, rapeseed to be screened can continue to be added to the screening chamber through the first channel chamber 21. In actual operation, the screen 14 is continuously flipped, thus achieving continuous screening and improving screening efficiency. Furthermore, by setting the screen 14 and the screening plate 31 for two-stage screening, the screening pressure can be reduced, further improving the screening effect.

[0030] After the equipment has been working for a period of time, a lot of impurities will accumulate in the screening chamber 1, and some impurities will also adhere to the inner wall of the screening chamber 1. At this time, stop the rotation of the square column 11, so that the two screening frames 13 and the screens 14 on them are in a vertical state and move the rotating tube 12 so that the connection between the slag discharge chamber 4 and the screening chamber 1 is between the two rotating plates 15. During the movement of the square column 11, the rotating plates 15 will scrape the impurities on the inner wall of the screening chamber 1. At this time, rotate the square column 11 again, and the screens 14 will continuously flip. The impurities on the screens 14 and the impurities on the inner wall of the screening chamber 1 will fall into the slag discharge chamber 4.

[0031] Preferred, such as Figure 3 As shown, bearing seats 16 are fixedly provided at both ends of the screening chamber 1, and drive columns 17 are coaxially connected to both ends of the square column 11. The drive columns 17 are set on the bearing seats 16. A rotating mechanism 18 is fixedly provided at one end of the screening chamber 1. In this example, the rotating mechanism 18 can be a rotating drive mechanical device such as a rotating motor or a rotating cylinder. The drive shaft of the rotating mechanism 18 is coaxially connected to one of the drive columns 17. A rotating seat 19 is fixedly provided at the other end of the screening chamber 1. The other drive column 17 is rotatably engaged with the rotating seat 19. The rotating mechanism 18 is used to drive the square column 11 to rotate through the drive column 17.

[0032] Preferred, such as Figure 3 and Figure 4 As shown, the first channel bin 21 is inclined, with its lower end connected to the feed bin 2 and its higher end connected to the baffle bin 22, which is arranged along the height direction of the screening bin 1. A baffle 23 is provided inside the baffle bin 22 and moves along its own height direction. The top of the baffle bin 22 is open. The other end of the baffle bin 22 is connected to the inclined second channel bin 24. The lower end of the second channel bin 24 is connected to the baffle bin 22, and its higher end is open for communication with the external storage bin.

[0033] This design connects the higher end of the second channel chamber 24 to the external storage chamber. The movable baffle 23 makes it easier to control the rapeseed to be screened into the first channel chamber 21, eliminating the need for manual feeding each time.

[0034] Preferred, such as Figure 3 and Figure 4As shown, the screening chamber 1 is open at both ends, and the square column 11 extends out of the screening chamber 1 at both ends. A cam 110 is provided on one end of the square column 11 located outside one end of the screening chamber 1. The wheel part of the cam 110 with a larger radius is coaxially fixed to the square column 11. The cam 110 is located directly below the baffle chamber 22. The bottom of the baffle chamber 22 has two through holes 25. The lower end of the baffle 23 is connected to two sliding rods 26 along the height direction of the baffle chamber 22. The sliding rods 26 slide through the through holes 25 respectively. The lower end of the sliding rods 26 is connected to the same mating block 27. The mating block 27 is used to contact the cam 110. When the mating block 27 contacts the side of the wheel part with the smallest radius of the cam 110, the screening frame 13 is in a horizontal state, and the distance between the lower end of the baffle 23 and the bottom of the baffle chamber 22 is a predetermined value.

[0035] With this design, when the square column 11 drives the screening frame 13 and the screen 14 on it to rotate, the cam 110 on the square column 11 also rotates synchronously. When the cam 110 rotates, it contacts the mating block 27 to lift the mating block 27, so that the baffle 23 moves in the baffle chamber 22. When the baffle 23 rises, the rapeseed to be screened enters the first channel chamber 21 from the second channel chamber 24, thus realizing automatic feeding into the screening chamber 1.

[0036] Preferred, such as Figure 4 As shown, the baffle 23 has two sliding channels 28. The slide rod 26 slides through the sliding channels 28 and its upper end extends out of the sliding channels 28. The upper end of the baffle 23 is provided with a mounting frame 29. The mounting frame 29 is provided with a screw 210 parallel to the height direction of the baffle compartment 22. The lower end of the screw 210 is rotatably connected to the end of the baffle 23. The screw 210 is threaded with a lifting block 211. The upper end of the slide rod 26 is connected to the lifting block 211. The mounting frame 29 is provided with a rotating head 212 rotatably connected to it. The rotating head is coaxially connected to the screw 210.

[0037] This design allows the screw 210 to rotate by rotating the rotating head 212, which in turn drives the lifting block 211 to move up and down, thereby adjusting the distance between the baffle 23 and the mating block 27. When the distance between the baffle 23 and the mating block 27 is small, the single feeding time is short and the feeding amount is small. When the distance between the baffle 23 and the mating block 27 is large, the single feeding time is long and the feeding amount is large. In this way, the single feeding amount can be adjusted to match the optimal single feeding amount when the rotation speed of the square column 11 is different, thereby improving the screening efficiency.

[0038] Preferred, such as Figure 5As shown, an electric lead screw 111 parallel to the axial direction of the screening chamber 1 is fixedly installed at the other end of the screening chamber 1. The drive shaft of the electric lead screw 111 is threadedly fitted with a drive block 112. The drive block 112 is connected to a drive rod 113 parallel to the axial direction of the screening chamber 1. The drive rod 113 is coaxially connected to a drive wheel 114. A mating ring 115 is coaxially connected to the outer surface of the rotating plate 15 near the other end of the screening chamber 1. An annular groove 116 is opened on the inner side of the mating ring 115, and the drive wheel 114 is fitted into the annular groove 116.

[0039] With this design, the electric lead screw 111 is used to drive the drive wheel 114 to move, and then drive the rotating plate 15 and the rotating tube 12 to move on the square column 11 through the mating ring 115.

[0040] Preferred, such as Figure 6 As shown, the lower ends of the discharge bin 3 and the slag discharge bin 4 are both connected to the receiving bin 5. The lower end of the receiving bin 5 is connected to the inclined discharge hopper 51, which is used to transport the screened impurities and rapeseed to the next process.

[0041] Preferred, such as Figure 7 As shown, multiple air outlet pipes 117 arranged in a circumferential array around the central axis of the screening chamber 1 are connected between the rotating plates 15. In this example, there are a total of four air outlet pipes 117. Multiple air outlet holes 118 are passed through the pipe surface of the air outlet pipes 117 facing the rotating pipe 12. The end of the air outlet pipe 117 near the screening chamber 1 is connected to the outer plate surface of the corresponding rotating plate 15. This connection is used to connect with the external air supply mechanism, and then air is sprayed into the screening chamber 1 through the air outlet holes 118. A dust suction pipe 119 is connected to the upper surface of the feeding chamber 2. The dust suction pipe 119 is used to connect with the external air suction mechanism, and then sucks away the dust in the screening chamber 1.

[0042] In order to avoid the final screening of fine dust particles smaller than rapeseed, this embodiment sets the air outlet pipe 117 to spray air upwards when the rapeseed is being screened. This blows the fine dust particles upwards, making it easier for the dust suction pipe 119 to suck them away. At the same time, the sprayed air can also blow the rapeseed, which can accelerate the screening process and improve the screening efficiency.

[0043] Preferred, such as Figure 7 and Figure 8As shown, a ring track 120 is coaxially provided on the outer side of the rotating plate 15 near one end of the screening chamber 1. One end of each air outlet pipe 117 is connected to the ring track 120. An arc-shaped strip 121 is fitted inside the ring track 120. The arc-shaped strip 121 is used to block the connection between the corresponding end of the air outlet pipe 117 and the ring track 120. The arc-shaped strip 121 is located on the upper part of the ring track 120. An annular plate 122 is coaxially connected to the arc-shaped strip 121. The annular plate 122 slides in contact with the surface of the annular track 120 facing away from the rotating plate 15. Multiple fixing hooks 123 are connected to the outer side of the annular plate 122. In this example, it is set that... There are four fixed hooks 123; an annular bar 124 is coaxially connected to the outer side of the annular track 120, and the fixed hooks 123 are all slidably hung on the annular bar 124. The lower part of the annular plate 122 is connected to a vent pipe 125, which is used to connect to an external air supply mechanism; the annular plate 122 is connected to two limiting rods 126 arranged along the central axis of the screening chamber 1. Two limiting sleeves 127 are fixed to one end of the screening chamber 1. The limiting rods 126 are slidably inserted into the limiting sleeves 127 respectively. The limiting rods 126 and the limiting sleeves 127 are used to support the annular plate 122 and the arc-shaped bar 121 to prevent them from rotating with the annular track 120.

[0044] This design ensures that the air outlet pipe 117, which is located below the screen 14, always sprays air upwards in the current state, without the need for manual adjustment of the air outlet pipe 117's spray state.

[0045] Further preferred, such as Figure 9 As shown, two support rods 6 are connected to the outer side of the screening chamber 1 along its own axial direction. The support rods 6 are respectively set on two support frames 61, which are set on the horizontal mounting surface of the equipment. The limiting sleeves 127 are respectively installed on the two support rods 6. One end of the two support rods 6 is connected to a first support plate 62. One bearing seat 16 and the rotating mechanism 18 are set on the first support plate 62. The other end of the two support rods 6 is connected to a second support plate 63. The other bearing seat 16 and the rotating seat 19 are both set on the second support plate 63. The outer frame of the electric lead screw 111 is connected to the second support plate 63.

[0046] The above description is only a preferred embodiment of this application and is not intended to limit this application. Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application.

Claims

1. Rapeseed screening apparatus, characterized in that, The utility model relates to a screening device, including: The square column (11) is provided with a rotating tube (12) in the coaxial sliding sleeve, the rotating tube (12) is connected with the screening frame (13) that is arranged in the central symmetry around the central axis, the screening frame (13) is equipped with the screen (14) in, the outer side of screening frame (13) is in sliding contact with the inner wall of screening bin (1), the both ends of rotating tube (12) are connected with the rotating plate (15) in the coaxial, the opposite board surface of two rotating plates (15) is connected with screening frame (13), and the side of rotating plate (15) is in sliding contact with the inner wall of screening bin (1); The feeding bin (2) is located on the upper portion of one end of the screening bin (1) and is communicated with the same, and the feeding bin (2) is communicated with the first channel bin (21); The discharging bin (3) is located on the lower portion of one end of the screening bin (1) and is communicated with the same, and the discharging bin (3) is provided with a screening plate (31) at the communication part with the screening bin (1), the screening plate (31) is in the shape of an arc coaxial with the screening bin (1) and the inner arc surface thereof matches the radius of the inner wall of the screening bin (1), and the length of the screening plate (31) along the axial direction of the screening bin (1) matches the length of the rotating tube (12); The discharging bin (4) is located on the lower portion of the other end of the screening bin (1) and is communicated with the same, and the length of the discharging bin (4) along the axial direction of the screening bin (1) matches the length of the rotating tube (12) at the communication part with the screening bin (1).

2. Rapeseed screening apparatus according to claim 1, characterized in that The both ends of the screening bin (1) are fixedly provided with bearing seats (16) outside, the both ends of the square column (11) are coaxially connected with driving columns (17), the driving columns (17) are arranged on the bearing seats (16), the one end of the screening bin (1) is fixedly provided with a rotating mechanism (18) outside, the driving shaft of the rotating mechanism (18) is coaxially connected with one of the driving columns (17), and the other end of the screening bin (1) is fixedly provided with a rotating seat (19) outside, and the other driving column (17) is rotatably matched with the rotating seat (19).

3. Rapeseed screening apparatus according to claim 1, characterized in that, The first channel bin (21) is arranged obliquely, the lower end thereof is communicated with the feeding bin (2), the higher end thereof is communicated with a baffle bin (22) arranged along the height direction of the screening bin (1), the baffle bin (22) is movably provided with a baffle (23) along the height direction thereof, the top of the baffle bin (22) is arranged open, and the other end of the baffle bin (22) is communicated with a second channel bin (24) arranged obliquely, the lower end of the second channel bin (24) is communicated with the baffle bin (22), and the higher end thereof is arranged open.

4. Rapeseed screening apparatus according to claim 3, characterized in that The screening bin (1) is open at both ends and the square column (11) extends out of the screening bin (1) at both ends, a cam (110) is arranged on one end of the square column (11) located outside one end of the screening bin (1), the cam (110) is coaxially fixed on the wheel part with large radius of the square column (11), the cam (110) is located directly below the baffle bin (22), the bottom of the baffle bin (22) is provided with a through opening (25), the lower end of the baffle (23) is connected with a sliding rod (26) along the height direction of the baffle bin (22), the sliding rod (26) is slidably arranged in the through opening (25), the lower end of the sliding rod (26) is connected with a matching block (27), the matching block (27) is used for contacting the cam (110), and when the matching block (27) contacts the side edge of the wheel part with the smallest radius of the cam (110), the screening frame (13) is in a horizontal state, and the distance between the lower end of the baffle (23) and the bottom of the baffle bin (22) is a predetermined value.

5. Rapeseed screening apparatus according to claim 4, characterized in that The baffle (23) is provided with a sliding channel (28), the sliding rod (26) is slidably arranged in the sliding channel (28) and the upper end of the sliding rod (26) extends out of the sliding channel (28), the upper end of the baffle (23) is provided with a mounting frame (29), the mounting frame (29) is provided with a screw rod (210) parallel to the height direction of the baffle bin (22), the lower end of the screw rod (210) is rotatably connected to the upper end of the baffle (23), the screw rod (210) is threadedly connected with a lifting block (211), the upper end of the sliding rod (26) is connected with the lifting block (211), the mounting frame (29) is provided with a rotating head (212) rotatably connected, and the rotating head is coaxially connected with the screw rod (210).

6. Rapeseed screening apparatus according to claim 1, characterized in that The other end of the screening bin (1) is fixedly provided with an electric screw rod (111) parallel to the axial direction of the screening bin (1), the driving shaft of the electric screw rod (111) is threadedly connected with a driving block (112), the driving block (112) is connected with a driving rod (113) parallel to the axial direction of the screening bin (1), the driving rod (113) is coaxially connected with a driving wheel (114), the outer side surface of the rotating plate (15) close to the other end of the screening bin (1) is coaxially connected with a matching ring (115), the inner side of the matching ring (115) is provided with an annular groove (116), and the driving wheel (114) is matched in the annular groove (116).

7. Rapeseed screening apparatus according to claim 1, characterized in that The discharge bin (3) and the slag discharge bin (4) are both communicated with a receiving bin (5) at the lower end, and the receiving bin (5) is communicated with an inclined discharge hopper (51) at the lower end.

8. Rapeseed screening apparatus according to claim 1, characterized in that The rotating plate (15) is connected with a plurality of gas outlet pipes (117) arranged in a circumferential array around the central axis of the screening bin (1), the pipe surface of the gas outlet pipe (117) facing the rotating pipe (12) is provided with a plurality of gas outlet holes (118), the end of the gas outlet pipe (117) close to one end of the screening bin (1) is communicated with the outer side surface of the corresponding rotating plate (15), and the upper surface of the feeding bin (2) is communicated with a dust suction pipe (119).

9. Rapeseed screening apparatus according to claim 8, characterized in that, The outer side surface of the rotating plate (15) near one end of the screening bin (1) is coaxially provided with an annular track (120), one end of the air outlet pipe (117) is communicated to the annular track (120), the annular track (120) is matched with an arc-shaped strip (121), the arc-shaped strip (121) is arranged on the upper portion of the annular track (120), the arc-shaped strip (121) is coaxially connected with an annular plate (122), the annular plate (122) is in sliding contact with the surface of the annular track (120) away from the rotating plate (15), the outer side edge of the annular plate (122) is connected with a plurality of fixed hooks (123), the outer side surface of the annular track (120) is coaxially connected with an annular strip (124), the fixed hooks (123) are all slidably hung on the annular strip (124), the lower portion of the annular plate (122) is communicated with an air pipe (125), the annular plate (122) is connected with two limiting rods (126) arranged along the central axis of the screening bin (1), two limiting sleeves (127) are fixedly arranged on one end of the screening bin (1), and the limiting rods (126) are respectively slidably arranged in the limiting sleeves (127).

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