Multi-stage pneumatic screen

Abstract

The utility model provides a multi-stage pneumatic screen. The multi-stage pneumatic screen comprises a bottom mounting box, a mounting disc, a plurality of groups of elastic connecting pieces, a discharging disc, a plurality of layers of circular screen discs and a pneumatic vibration mechanism, wherein the mounting disc is positioned above the bottom mounting box; the elastic connecting pieces are elastically connected with the mounting disc and the bottom mounting box; the discharging disc is mounted above the mounting disc; and the multiple layers of circular sieve trays are sequentially stacked up and down. The pneumatic vibration mechanism comprises a pneumatic motor fixedly installed in the bottom installation box, an installation base fixedly installed on the installation disc, a rotating shaft rotationally installed in the installation base, an eccentric block fixedly installed on the rotating shaft and a flat belt connected with an output shaft of the pneumatic motor and the rotating shaft. The firework bright beads with different particle sizes can be classified and screened through one set of equipment at the same time. According to the technical scheme, a very ingenious structure is utilized, the production efficiency is greatly improved, manual intervention is reduced, safe production is ensured, the service life is long, and the very good market application value is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of material screening, in particular to a multi-stage pneumatic screen. Background Art

[0002] When manufacturing fireworks and firecrackers, it is necessary to first granulate the pyrotechnic powder to form firework beads, then screen them according to their particle size, and coat the screened firework beads with powder, etc. After that, according to the needs of the fireworks products, the powder-coated firework beads of predetermined particle size are filled into corresponding shells respectively, and then subjected to subsequent processing.

[0003] However, when screening fireworks beads of different particle sizes, a single screen is usually used for screening. But since only one screen can be operated at a time, when fireworks beads of multiple different particle sizes need to be classified and screened, it is necessary to use multiple screens with different apertures for screening in turn. This cannot meet the production and manufacturing needs of large quantities of fireworks and firecrackers.

[0004] In addition, the existing screening device generally adopts the method of driving the eccentric block to vibrate by a motor, but the motor is easily damaged because it is in a vibrating working state for a long time, and the service life is not long, which will lead to high production costs. Utility Model Content

[0005] The main purpose of the utility model is to provide a multi-stage pneumatic screen that is not easy to be damaged, so as to solve the problem that it is impossible to classify and screen fireworks beads of multiple different particle sizes at the same time.

[0006] In order to achieve the above-mentioned purpose, the utility model provides a multi-stage pneumatic screen, comprising:

[0007] Bottom mounting box;

[0008] A mounting plate, the mounting plate being located above the bottom mounting box;

[0009] A plurality of groups of elastic connectors, each of which elastically connects the mounting plate and the bottom mounting box;

[0010] A discharging tray, the discharging tray is installed above the mounting tray;

[0011] Multi-layer circular sieve plates, wherein the multi-layer circular sieve plates are stacked up and down in sequence, and the circular sieve plates at the bottom layer are installed above the discharge plate; the discharge plate and each layer of the circular sieve plates are provided with a discharge guide groove;

[0012] A pneumatic vibration mechanism, the pneumatic vibration mechanism includes an air motor fixedly installed in the bottom mounting box, a mounting base fixedly installed on the mounting plate, a rotating shaft rotatably installed in the mounting base, an eccentric block fixedly installed on the rotating shaft, and a flat belt connecting the output shaft of the air motor and the rotating shaft, wherein the flat belt is bent into an arc.

[0013] Optionally, the flat belts are arranged in pairs and symmetrically, the upper ends of the flat belts are fixedly mounted on the rotating shaft via a first flange sleeve, and the lower ends of the flat belts are fixedly mounted on the output shaft of the pneumatic motor via a second flange sleeve.

[0014] Optionally, the eccentric blocks are fixed to both the upper end and the lower end of the rotating shaft, and the phase angle between the two eccentric blocks is 30° to 60°.

[0015] Optionally, the plurality of groups of elastic connectors are distributed in a ring array; the elastic connector is a spring, the upper end of the spring is connected to the mounting plate and the lower end of the spring is connected to the top surface of the bottom mounting box (10);

[0016] And / or, a cover plate is provided on the top of the discharge guide chute.

[0017] Optionally, the multi-stage pneumatic screen further comprises a plurality of lock buckles for clamping and fixing the mounting plate, the discharge plate and the multiple layers of the circular screen plates to each other, and the plurality of lock buckles are distributed in a circular array.

[0018] Optionally, the lock comprises a seat arranged on the circular screen plate of the top layer, a rotating handle hinged to the mounting plate through a first pin, and a pull rod hinged to the rotating handle through a second pin, wherein the first pin is located at the end of the rotating handle and the second pin is located in the middle of the rotating handle;

[0019] The free end of the pull rod can be hooked on the clamping seat, and when the free end of the rotating handle is rotated downward to the right position, the lock clamps the mounting plate, the discharge plate and the multiple layers of the circular screen plate.

[0020] Optionally, the circular sieve discs each include a first mounting tube and a sieve mesh, the upper and lower ends of the first mounting tube are both formed with flange edges, a first discharge port is formed on the side wall of the first mounting tube, and the discharge guide groove is connected to the first discharge port;

[0021] The screen is installed at the lower end corresponding to the first installation tube, and the edge of the screen is clamped between the flange edges of the adjacent first installation tubes.

[0022] Optionally, the edge of the screen is wrapped with a sealing ring, the cross-section of the sealing ring is U-shaped, and the sealing ring is located between the edge of the screen and the flange.

[0023] Optionally, the mesh size of the sieve located in the upper layer is larger than the mesh size of the sieve located in the lower layer;

[0024] And / or, a cross dividing rod is provided on the upper surface of the screen.

[0025] Optionally, the discharge tray comprises a second mounting tube and a conical tray, a second discharge port is provided on the side wall of the second mounting tube, and the discharge guide groove is connected to the second discharge port;

[0026] The edge of the conical disk is disposed at the lower end of the second mounting tube, and the tip of the conical disk faces upward and extends into the second mounting tube;

[0027] A material guide plate is also arranged at the edge of the second material outlet in the second installation cylinder.

[0028] In the multi-stage pneumatic screen of the utility model, the upper surface of the bottom mounting box supports the mounting plate, the discharge plate and the circular screen plate through elastic connectors. When the pneumatic motor installed on the bottom mounting box is started, the rotational torque generated by its output shaft will be transmitted to the rotating shaft through the flat belt, and the rotating shaft will drive the eccentric block to rotate, thereby generating rotational vibration and up and down vibration effects. The mounting plate used to fix the mounting seat will transmit the vibration generated by the eccentric block to the discharge plate and the circular screen plate, thereby driving the materials on the circular screen plate and the discharge plate to perform outward expansion involute motion. Due to the presence of the elastic connector and the flat belt, the vibration will not affect the bottom mounting box and the pneumatic motor, thereby ensuring the reliability of the equipment installation.

[0029] When screening, fireworks beads of different particle sizes will first be deposited on the top circular sieve plate. As the circular sieve plate and the discharge plate vibrate, fireworks beads with smaller particle sizes will pass through the multiple layers of circular sieve plates from top to bottom and fall down until they reach the discharge plate for discharge. In addition, fireworks beads with medium particle sizes will stay on the middle circular sieve plate and be discharged from the edge of the middle circular sieve plate, while fireworks beads with the largest particle sizes will always stay on the top circular sieve plate and be discharged from the edge of the top circular sieve plate as they vibrate. Among them, the mesh aperture of the circular sieve plate on the upper layer is larger than the mesh aperture of the circular sieve plate on the lower layer, and the number of layers and mesh aperture of the circular sieve plate can be set according to actual conditions, so that fireworks beads of multiple different particle sizes can be classified and screened in sequence at the same time through a set of equipment.

[0030] The above technical solution utilizes a very clever structure to greatly improve production efficiency, reduce manual intervention to ensure safe production, is strong and durable, has a long service life, and has great market application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0032] Figure 1 It is a structural schematic diagram of the multi-stage pneumatic screen of the utility model;

[0033] Figure 2 It is a front view schematic diagram of the lock buckle of the utility model;

[0034] Figure 3 yes Figure 1 The enlarged view of point A in the middle;

[0035] Figure 4 It is a cross-sectional view of the discharging tray of the utility model;

[0036] Figure 5 yes Figure 4 A top view of

[0037] Figure 6 It is a top view of the circular sieve plate of the utility model.

[0038] 10: Bottom mounting box;

[0039] 20: Installation disk;

[0040] 30: elastic connector;

[0041] 40: discharge tray; 41: second mounting cylinder; 411: second discharge port; 42: conical tray; 43: guide plate;

[0042] 50: round sieve plate; 51: first mounting cylinder; 511: flange edge; 52: sealing ring; 53: sieve; 531: cross dividing rod;

[0043] 60: pneumatic vibration mechanism; 61: pneumatic motor; 62: mounting seat; 63: rotating shaft; 64: eccentric block; 65: flat belt; 651: first flange sleeve; 652: second flange sleeve;

[0044] 70: discharging guide chute;

[0045] 80: lock buckle; 81: clamping seat; 82: pull rod; 83: rotating handle; 831: first pin shaft; 832: second pin shaft.

[0046] The purpose, features and advantages of the present invention will be further described in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0047] The technical solution in this embodiment will be described clearly and completely below in conjunction with the drawings in this embodiment. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of them. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0048] It should be noted that all directional indications in this embodiment (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0049] In the present invention, unless otherwise clearly defined and limited, the terms "connection", "fixation" and the like should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0051] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0052] Please combine Figure 1As shown, the multi-stage pneumatic screen provided in one embodiment of the utility model includes a bottom mounting box 10, a mounting plate 20, multiple sets of elastic connectors 30, a discharge plate 40, a multi-layer circular screen plate 50 and a pneumatic vibration mechanism 60. Among them, the mounting plate 20 is located above the bottom mounting box 10; the elastic connectors 30 are elastically connected to the mounting plate 20 and the bottom mounting box 10; the discharge plate 40 is installed above the mounting plate 20; the multi-layer circular screen plates 50 are stacked up and down in sequence, and the circular screen plates 50 located at the bottom are installed above the discharge plate 40, wherein "stacked" in the utility model refers to stacking and connecting in sequence, and adjacent circular screen plates 50 can be detachably fixed by locking members (for example, lock buckles or annular clamps). The discharge plate 40 and each layer of the circular screen plates 50 are provided with a discharge guide groove 70, wherein the top of the discharge guide groove 70 is preferably provided with a cover plate to prevent debris from falling into the discharge guide groove 70. The pneumatic vibration mechanism 60 includes an air motor 61 fixedly mounted in the bottom mounting box 10, a mounting seat 62 fixedly mounted on the mounting plate 20, a rotating shaft 63 rotatably mounted in the mounting seat 62, an eccentric block 64 fixedly mounted on the rotating shaft 63, and a flat belt 65 connecting the output shaft of the air motor 61 and the rotating shaft 63. The rotating shaft 63 can be rotatably mounted in the mounting seat 62 through a pair of bearings capable of axial limiting, and both ends of the rotating shaft 63 extend from the mounting seat 62 to facilitate the installation of the eccentric block 64.

[0053] The flat belt 65 is bent into an arc (such as Figure 1 As shown in FIG. 1 , the length of the flat belt 65 is greater than the distance between the output shaft of the pneumatic motor 61 and the rotating shaft 63. Moreover, the flat belts 65 are preferably arranged in pairs and symmetrically. The upper end of the flat belt 65 is fixedly mounted on the rotating shaft 63 through a first flange sleeve 651, and the lower end of the flat belt 65 is fixedly mounted on the output shaft of the pneumatic motor 61 through a second flange sleeve 652. Since the flat belt 65 is a hard material that can be bent and its width is greater than 5 cm, when connecting the output shaft of the pneumatic motor 61 and the rotating shaft 63, the rotation torque can be well transmitted. Moreover, since the flat belt 65 can be bent and deformed, it can buffer the vibration generated by the eccentric block 64, thereby reducing the influence of the vibration on the service life of the pneumatic motor 61.

[0054] In a preferred embodiment, eccentric blocks 64 are fixed to the upper and lower ends of the rotating shaft 63, and the phase angle between the two eccentric blocks 64 is 30° to 60°. By adjusting the phase angle between the two eccentric blocks 64, the amplitude of the rotational vibration can be adjusted, the motion trajectory of the material on the screen surface can be changed, and the material can be finely screened, probabilistically screened, etc. The phase angle refers to the central angle corresponding to the projection of the two eccentric blocks 64 on the horizontal plane.

[0055] In the multi-stage pneumatic screen of the utility model, the upper surface of the bottom mounting box 10 supports the mounting plate 20, the discharge plate 40 and the circular screen plate 50 through the elastic connector 30. When the pneumatic motor 61 installed on the bottom mounting box 10 is started, the rotation torque generated by its output shaft will be transmitted to the rotating shaft 63 through the flat belt 65, and the rotating shaft 63 will drive the eccentric block 64 to rotate, thereby generating a rotational vibration and an up-and-down vibration effect. The mounting plate 20 used to fix the mounting seat 62 will transmit the vibration generated by the eccentric block 64 to the discharge plate 40 and the circular screen plate 50, thereby driving the materials on the circular screen plate 50 and the discharge plate 40 to perform an outward expansion involute motion. Due to the presence of the elastic connector 30 and the flat belt 65, the vibration will not affect the bottom mounting box 10 and the pneumatic motor 61, thereby ensuring the reliability of the equipment installation.

[0056] When screening, fireworks beads of different particle sizes will first be deposited on the top circular sieve plate 50. As the circular sieve plate 50 and the discharge plate 40 vibrate, fireworks beads with smaller particle sizes will pass through the multiple layers of circular sieve plates 50 from top to bottom and fall down until they reach the discharge plate 40 for discharge. In addition, fireworks beads with medium particle sizes will stay on the middle circular sieve plate 50 and be discharged from the edge of the middle circular sieve plate 50, while fireworks beads with the largest particle sizes will always stay on the top circular sieve plate 50 and be discharged from the edge of the top circular sieve plate 50 with vibration. Among them, the mesh aperture of the circular sieve plate 50 located on the upper layer is larger than the mesh aperture of the circular sieve plate 50 located on the lower layer, and the number of layers and mesh aperture of the circular sieve plate 50 can be set according to actual conditions, so that fireworks beads of multiple different particle sizes can be classified and screened in sequence at the same time through a set of equipment. The above technical solution utilizes a very clever structure to greatly improve production efficiency, reduce manual intervention to ensure safe production, is strong and durable, has a long service life, and has great market application value.

[0057] See again Figure 1 The plurality of groups of elastic connectors 30 are distributed in a circular array, and the number of the groups may be at least three. The elastic connector 30 is a spring, the upper end of the spring is connected to the mounting plate 20 and the lower end of the spring is connected to the top surface of the mounting box 10, thereby playing a role in buffering vibration.

[0058] In a more preferred embodiment, Figure 1 and Figure 2As shown, the multi-stage pneumatic screen also includes a plurality of lock buckles 80 for clamping and fixing the mounting plate 20, the discharge plate 40 and the multi-layer circular screen plate 50 to each other. The plurality of lock buckles 80 are distributed in a circular array so that the mounting plate 20, the discharge plate 40 and the multi-layer circular screen plate 50 vibrate as a whole. The lock buckle 80 may include a holder 81 disposed on the circular screen plate 50 of the top layer, a rotating handle 83 hinged to the mounting plate 20 via a first pin 831, and a pull rod 82 hinged to the rotating handle 83 via a second pin 832. The first pin 831 is located at the end of the rotating handle 83, and the second pin 832 is located in the middle of the rotating handle 83. The free end of the pull rod 82 can be hung on the holder 81. Specifically, see Figure 2 The pull rod 82 is preferably a U-shaped structure, the open end of which is hinged to the middle of the rotating handle 83 through the second pin 832, and the bent section thereof is formed into a hook, which can be hung on the holder 81. When the free end of the rotating handle 83 is rotated downward to a position based on the first pin 831, the lock 80 clamps the mounting plate 20, the discharge plate 40 and the multi-layer circular screen plate 50. When the free end of the rotating handle 83 is rotated upward to a position based on the first pin 831, the free end of the pull rod 82 can be disengaged from the holder 81, so that the mounting plate 20, the discharge plate 40 and the multi-layer circular screen plate 50 are released from each other.

[0059] like Figure 1 , Figure 3 and Figure 6 As shown, each layer of the circular screen disc 50 includes a first mounting cylinder 51 and a screen 53. The upper and lower ends of the first mounting cylinder 51 are formed with flange edges 511. The side wall of the first mounting cylinder 51 is provided with a first discharge port (not shown), and the discharge guide groove 70 is connected to the first discharge port. The screen 53 is installed at the lower end of the corresponding first mounting cylinder 51, and the edge of the screen 53 is clamped between the flange edges 511 of the adjacent first mounting cylinders 51. Among them, the heights of the multiple layers of first mounting cylinders 51 can be the same or different, and the screen 53 can be a wire mesh or a porous plate, etc. The mesh aperture of the upper screen 53 will be larger than the mesh aperture of the lower screen 53. In addition, a cross dividing rod 531 is provided on the upper surface of the screen 53, so that the screen 53 can be divided into four sections, so that the material is confined to one of the sections when it rotates with the rotation. After the material collides with the cross dividing rod 531, the movement speed will be further increased, thereby improving the screening efficiency. For details, please refer to Figure 3 The screen 53 is installed at the lower end of the corresponding first installation cylinder 51 and is located below the first discharge port, so that the fireworks beads deposited on the screen 53 after screening can be discharged from the discharge guide groove 70 through the first discharge port. The edge of the screen 53 is clamped between the flange edges 511 of the upper and lower adjacent first installation cylinders 51, and the flange edges 511 of the upper and lower adjacent first installation cylinders 51 are fixed by the lock buckle 80, thereby realizing the reliable stacking of multiple layers of circular screen plates 50 in sequence.

[0060] In a preferred embodiment, see again Figure 3 The edge of the screen 53 is wrapped with a sealing ring 52, the cross section of the sealing ring 52 is U-shaped, and the sealing ring 52 is located between the edge of the screen 53 and the flange edge 511. The sealing ring 52 can seal the gap around the screen 53, and the sealing ring 52 can also buffer the relative vibration between the screen 53 and the flange edge 511, so as to extend the service life of the fastening and installation parts.

[0061] Furthermore, if Figure 1 , Figure 4 and Figure 5 As shown, the discharge tray 40 includes a second mounting tube 41 and a conical tray 42. A second discharge port 411 is provided on the side wall of the second mounting tube 41, and the discharge guide groove 70 is connected to the second discharge port 411. The lower end of the second mounting tube 41 is disposed on the edge of the conical tray 42, and the tip of the conical tray 42 faces upward and extends into the second mounting tube 41. When the fireworks beads pass through the bottom circular sieve tray 50 and fall onto the conical tray 42, the fireworks beads will move toward the edge of the conical tray 42 along with the vibrating conical tray 42 until they are discharged from the second discharge guide groove 322 through the second discharge port 411. Here, refer again to Figure 4 and Figure 5 A guide plate 43 is also provided at the edge of the second discharge port 411 in the second installation tube 41 , and the guide plate 43 can guide the firework beads rotating and moving on the conical disk 42 to the second discharge port 411 .

[0062] The multi-stage pneumatic screen of this utility model has low noise, high efficiency, exquisite and durable design, and only takes 3 to 5 minutes to quickly change the screen. Moreover, it adopts a fully enclosed structure and can be used for screening and filtering of materials such as particles, powders, and mucus. The mesh is not blocked, and the powder does not fly. It can be screened to 500 mesh or 0.028mm, and the minimum filtration can be 5 microns. In addition, it can also realize the automatic discharge of impurities and coarse materials for continuous operation.

[0063] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent structure or equivalent process transformation made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the protection scope of the present invention.

Claims

1. A multi-stage pneumatic screen, characterized in that: The multi-stage pneumatic screen comprises: Bottom mounting box (10); A mounting plate (20), the mounting plate (20) being located above the bottom mounting box (10); A plurality of groups of elastic connecting members (30), each of the elastic connecting members (30) elastically connecting the mounting plate (20) and the bottom mounting box (10); a discharge tray (40), the discharge tray (40) being installed above the mounting tray (20); A plurality of layers of circular sieve plates (50), wherein the plurality of layers of circular sieve plates (50) are stacked one above the other, and the circular sieve plates (50) at the bottom layer are installed above the discharge plate (40); the discharge plate (40) and each layer of the circular sieve plates (50) are provided with a discharge guide groove (70); A pneumatic vibration mechanism (60), the pneumatic vibration mechanism (60) comprising an air motor (61) fixedly mounted in the bottom mounting box (10), a mounting seat (62) fixedly mounted on the mounting plate (20), a rotating shaft (63) rotatably mounted in the mounting seat (62), an eccentric block (64) fixedly mounted on the rotating shaft (63), and a flat belt (65) connecting the output shaft of the air motor (61) and the rotating shaft (63), wherein the flat belt (65) is bent into an arc shape.

2. The multi-stage pneumatic screen according to claim 1, characterized in that: The flat belts (65) are arranged in pairs and symmetrically. The upper ends of the flat belts (65) are fixedly mounted on the rotating shaft (63) via a first flange sleeve (651), and the lower ends of the flat belts (65) are fixedly mounted on the output shaft of the pneumatic motor (61) via a second flange sleeve (652).

3. The multi-stage pneumatic screen according to claim 1, characterized in that: The eccentric blocks (64) are fixed to the upper and lower ends of the rotating shaft (63), and the phase angle between the two eccentric blocks (64) is 30° to 60°.

4. The multi-stage pneumatic screen according to claim 1, characterized in that: A plurality of groups of the elastic connecting members (30) are distributed in a circular array; the elastic connecting members (30) are springs, the upper ends of the springs are connected to the mounting plate (20) and the lower ends of the springs are connected to the top surface of the bottom mounting box (10); And / or, a cover plate is provided on the top of the discharge guide trough (70).

5. The multi-stage pneumatic screen according to any one of claims 1 to 4, characterized in that: The multi-stage pneumatic screen also includes a plurality of lock buckles (80) for clamping and fixing the mounting plate (20), the discharge plate (40) and the multiple layers of the circular screen plates (50) to each other, and the plurality of lock buckles (80) are distributed in a circular array.

6. The multi-stage pneumatic screen according to claim 5, characterized in that: The lock buckle (80) comprises a holder (81) arranged on the top circular screen plate (50), a rotating handle (83) hinged to the mounting plate (20) via a first pin shaft (831), and a pull rod (82) hinged to the rotating handle (83) via a second pin shaft (832), wherein the first pin shaft (831) is located at the end of the rotating handle (83), and the second pin shaft (832) is located in the middle of the rotating handle (83); The free end of the pull rod (82) can be hooked on the holder (81), and when the free end of the rotating handle (83) is rotated downward into position, the lock (80) clamps the mounting plate (20), the discharge plate (40) and the multiple layers of the circular screen plate (50).

7. The multi-stage pneumatic screen according to any one of claims 1 to 4, characterized in that: The circular sieve disc (50) comprises a first mounting tube (51) and a sieve (53); the upper and lower ends of the first mounting tube (51) are both formed with flange edges (511); a first discharge port is formed on the side wall of the first mounting tube (51); and the discharge guide groove (70) is connected to the first discharge port; The screen (53) is installed at the lower end corresponding to the first installation tube (51), and the edge of the screen (53) is clamped between the flange edges (511) of the adjacent first installation tubes (51).

8. The multi-stage pneumatic screen according to claim 7, characterized in that: The edge of the screen (53) is wrapped with a sealing ring (52), the cross section of the sealing ring (52) is U-shaped, and the sealing ring (52) is located between the edge of the screen (53) and the flange edge (511).

9. The multi-stage pneumatic screen according to claim 7, characterized in that: The mesh size of the sieve (53) located at the upper layer is larger than the mesh size of the sieve (53) located at the lower layer; And / or, a cross dividing rod (531) is provided on the upper surface of the screen (53).

10. The multi-stage pneumatic screen according to any one of claims 1 to 4, characterized in that: The discharge tray (40) comprises a second mounting tube (41) and a conical tray (42); a second discharge port (411) is provided on the side wall of the second mounting tube (41); and the discharge guide groove (70) is connected to the second discharge port (411); The edge of the conical disk (42) is disposed at the lower end of the second mounting tube (41), and the tip of the conical disk (42) faces upward and extends into the second mounting tube (41); A material guide plate (43) is also provided at the edge of the second material outlet (411) in the second installation cylinder (41).

Images