Screening mechanism and roller powder coating machine

Abstract

The present invention discloses a screening mechanism and a roller powder coating machine, which relate to a roller powder coating technology, comprising a powder coating drum that is driven to rotate, with both ends of the powder coating drum being open and arranged obliquely, the higher end of the powder coating drum being a feeding end, and the lower end of the powder coating drum being a discharging end, the discharging end of the powder coating drum being provided with a first screening net, a collecting cavity being formed on the outer side of the powder coating drum, the first screening net being located in the annular screening cavity, and further comprising a conveying component, the conveying component being used for screening the powder at the bottom of the collecting cavity and delivering it to the feeding end of the powder coating drum. The screening mechanism and the roller powder coating machine provided by the present invention perform initial screening and separation on the coated powder and food materials through the first screening net, and then the conveying component removes large particles from the powder and delivers it to the powder coating drum, with good screening effect.

Description

Technical Field

[0001] The invention relates to a roller powder coating technology, in particular to a screening mechanism and a roller powder coating machine. Background Art

[0002] The drum coating machine coats the product surface with a uniform layer of coating powder through the rotation of the drum, thereby increasing the amount of coating on the product and producing a scaly shape. It is suitable for coating bulk materials (bread crumbs) such as popcorn chicken, chicken nuggets, fish nuggets, etc. Due to the drum design, the folds and concave and convex areas of the product can also be evenly coated with powder.

[0003] For example, the Chinese patent application number is CN202121200041.7, and the publication date is 2021.05.31. The application relates to a drum-type flour coating machine, which includes a frame, and a drum is rotatably connected to the upper end of the frame. A lifting mechanism for driving the end of the drum to lift and lower is provided at one end of the frame. A conveying mechanism is provided at the end of the frame away from the lifting mechanism. The drum includes a rotating drum and a flour coating drum. The flour coating drum is provided with a plurality of through holes. Guide plates are provided inside the rotating drum and the flour coating drum. The flour coating drum is located at the upper end of the conveying mechanism and is directly opposite to the conveying mechanism. This application has the effect of high efficiency in flour coating squid.

[0004] In the prior art, after the food is coated with powder by the drum coating machine, the powder and the food enter the screening net for separation at the same time, and the recovered powder is mixed with large wet particles, resulting in poor screening effect. Summary of the Invention

[0005] The object of the present invention is to provide a screening mechanism and a roller powder coating machine to solve the above-mentioned deficiencies in the prior art.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A screening mechanism comprises a powder coating drum driven to rotate, the powder coating drum being open at both ends and arranged obliquely, the higher end of the powder coating drum being a feeding end, the lower end of the powder coating drum being a discharging end, a first screening net being provided at the discharging end of the powder coating drum, a collecting cavity being formed on the outer side of the powder coating drum, and the first screening net being located within the annular screening cavity;

[0008] The utility model also comprises a conveying component, which is used for screening the powder material at the bottom of the collecting cavity and then conveying it to the feeding end of the powder coating cylinder.

[0009] The above-mentioned screening mechanism, the conveying assembly includes a conveying member and a screening member, the feed port of the conveying member is connected to the bottom of the collecting chamber, the discharge port of the conveying member is connected to the upper part of the collecting chamber near the feed end of the powder coating tube, and the screening member is arranged on the circumference of the feed end of the powder coating tube and connects the inside and outside of the powder coating tube.

[0010] The above-mentioned screening mechanism, the screening element includes a second screening mesh and a grinding roller, a screening port is provided at the feeding end of the powder coating tube, the screening port is connected to the collecting chamber, brackets are provided on both sides of the screening port, a first through hole is provided on the surface of the bracket, a positioning pin is slidably inserted in the first through hole, a plurality of connecting rods parallel to each other are provided on both sides of the second screening mesh, one end of the connecting rod is rotatably connected to the second screening mesh, and the other end of the connecting rod is rotatably connected to the bracket, a second through hole is provided on the surface of the second screening mesh, the axis of the second through hole and the first through hole are in the same straight line, a rack is provided on the surface of the second screening mesh, two moving blocks are movably connected to the two brackets, two ends of the grinding roller are rotatably connected to the two moving blocks, the grinding roller is in contact with the surface of the second screening mesh, gears are provided at both ends of the grinding roller, the gears are meshed with the rack, and a driving member is provided on the moving block for driving the grinding roller to rotate.

[0011] The above-mentioned screening mechanism, the feeding end of the powder coating tube is sleeved with a storage tube, the powder coating tube passes through the storage tube, an annular cavity is formed between the inner wall of the storage tube and the outer wall of the powder coating tube, the discharge port of the spiral auger is connected to the storage tube, the second screening net is inside the annular cavity, and a scraper is fixed on the outer surface of the powder coating tube, the scraper is located on one side of the second screening net, and a gap is left between the scraper and the annular cavity.

[0012] The above-mentioned screening mechanism has a movable plate on the scraper surface, which is movably connected to the scraper surface. The scraper surface is provided with an electric push rod, and the output end of the electric push rod is fixed on the scraper surface to drive the movable plate to move linearly.

[0013] The above-mentioned screening mechanism, the second screening net includes a frame portion and a screening net portion, the screening net portion is slidably connected to the frame portion, an elastic member is provided on the surface of the screening net portion, and one end of the elastic member is fixed to the frame portion.

[0014] A drum powder coating machine comprises the above-mentioned screening mechanism.

[0015] In the above-mentioned grinding device, a feeding conveyor mesh belt is provided on one side of the feeding end of the powder coating tube. The feeding conveyor mesh belt includes a horizontal section and an inclined section. One end of the inclined section of the feeding conveyor mesh belt extends into the powder coating tube.

[0016] The above-mentioned drum flour coating machine also includes a pre-flour coating mechanism, which is used to pre-flour the food on the feeding conveyor belt.

[0017] In the above-mentioned roller powder coating machine, the pre-powder coating mechanism includes a vibrating screen, and the discharge port of the vibrating screen is located above the conveying surface of the feeding conveyor mesh belt.

[0018] The beneficial effect of the present invention is that the powdered material and the food material are initially sieved and separated through the first screening net, and then the conveying component removes large particles from the powder and conveys it to the powder coating cylinder, so the screening effect is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments described in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0020] Figure 1 A schematic structural diagram of a screening mechanism and a roller powder coating machine provided in one embodiment of the present invention;

[0021] Figure 2 A schematic structural diagram of a powder coating tube provided by another embodiment of the present invention;

[0022] Figure 3 A schematic structural diagram of a powder coating tube provided in yet another embodiment of the present invention;

[0023] Figure 4 A schematic structural diagram of a storage cartridge provided by another embodiment of the present invention when opened from a first perspective;

[0024] Figure 5 A schematic structural diagram of a screening element from a first perspective provided by yet another embodiment of the present invention;

[0025] Figure 6 A schematic structural diagram of a screening element according to another embodiment of the present invention from a second perspective;

[0026] Figure 7 This is a schematic structural diagram of a storage cartridge provided by yet another embodiment of the present invention when opened from a second viewing angle.

[0027] Description of reference numerals:

[0028] 2-powder coating tube; 21-first screening net; 3-conveying assembly; 31-screw auger; 32-second screening net; 321-frame portion; 3211-second through hole; 322-screening net portion; 33-grinding roller; 34-bracket; 341-locating pin; 342-moving block; 343-limiting block; 35-connecting rod; 4-storage cylinder; 5-scraper; 51-electric push rod; 6-feeding conveyor belt. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0030] like Figure 1-7As shown, an embodiment of the present invention provides a screening mechanism, comprising a driven rotating powder coating tube 2 and a conveying assembly 3, wherein both ends of the powder coating tube 2 are open and arranged obliquely, the higher end of the powder coating tube 2 is a feeding end, and the lower end of the powder coating tube 2 is a discharging end, and a first screening net 21 is provided at the discharging end of the powder coating tube 2, a collecting cavity is formed on the outside of the powder coating tube 2, and the first screening net 21 is located in the collecting cavity, and the conveying assembly 3 is used to screen the powder at the bottom of the collecting cavity and send it to the feeding end of the powder coating tube 2.

[0031] Specifically, the powder coating cylinder 2 is used to coat the powder onto the wet bulk material. Generally speaking, the powder coating cylinder 2 is provided with a powder feeding channel. The feeding end of the powder coating cylinder 2 is used to input the wet bulk material. The powder is coated onto the wet bulk material by the rotation of the powder coating cylinder 2. Obviously, this process will produce some wet powder clumps that are not adhered to the bulk material and cannot be used further. The screening mechanism provided in this embodiment is used to screen out the powder clumps and powder at the discharge end to prevent them from being discharged with the product, and then screen again to send the still usable powder to the feeding end, while the wet powder clumps are discarded. The collecting chamber is an annular cavity, which at least surrounds the discharge end of the powder coating tube 2. It is also arranged obliquely to facilitate the powder (dry powder and wet powder mass) falling into it to slide to the bottom under the action of gravity. The conveying component 3 can be a spiral auger 31 and a second screening net 32. The threaded auger 31 is a multi-segment auger, that is, a plurality of adjacent auger sections. The conveying direction is horizontal conveying, then vertical conveying, and then horizontal conveying. Alternatively, a conveying component that can achieve the above-mentioned conveying direction in the prior art, such as vacuum suction conveying, etc., can also be applied. In this embodiment, the conveying component is a prior art and will not be described in detail. The feed port of the spiral auger 31 is connected to the bottom of the collecting chamber, and the discharge port of the spiral auger 31 is connected to the upper position of the collecting chamber located at the feed end of the powder coating tube 2. The second screening net 32 ​​is directly arranged on the circumference of the feed end of the powder coating tube 2, and makes the inside and outside of the powder coating tube 2 connected. The conveying component 3 is used to separate large particles in the powder to complete the screening and transportation of the powder. In essence, the spiral auger 31 conveys the material screened at the discharge end of the collecting chamber to the feed end of the collecting chamber through another channel.

[0032] Specifically, the first screening net 21 is arranged on the circumference of the discharge end of the powder coating tube 2, and the two are an integrated structure, and are connected to the inside and outside of the powder coating tube 2 through the first screening net 21, and the first screening net 21 is annular. When the food and powder roll on the powder coating tube 2 and slide downward along the inner wall of the powder coating tube 2 until passing through the first screening net 21, the powder and the food are separated, and the food is discharged from the discharge end of the powder coating tube 2, and the powder enters the collecting chamber. Then the spiral auger 31 transports the powder in the collecting chamber to the top of the feed end of the powder coating tube 2, and the powder is directly sprinkled on the second screening net 32 ​​on the surface of the rotating powder coating tube 2. Most of the qualified powder enters the powder coating tube 2, and large particles of powder and a small amount of qualified powder fall into the collecting chamber as the powder coating tube 2 rotates.

[0033] The beneficial effect of the embodiment of the present invention is that the screening mechanism provided by the embodiment of the present invention can perform primary screening and separation of the coated powder and food through the first screening net 21, and then perform secondary screening through the second screening net 32 ​​to remove large particles, and the screening effect is good.

[0034] In another embodiment provided by the present invention, the conveying assembly 3 includes a conveying member and a screening member. The feed port of the conveying member (the conveying member may be a spiral auger 31) is connected to the bottom of the collecting chamber, and the discharge port of the conveying member is connected to the upper part of the collecting chamber near the feed end of the powder coating tube 2. The screening member is arranged in the circumferential direction of the feed end of the powder coating tube 2 and connects the inside and outside of the powder coating tube 2. The screening member passes through the discharge port of the conveying member as the powder coating tube 2 rotates. The screening member is used to perform secondary screening on the powder screened by the first screening net 21 to remove large particles of powder.

[0035] In another embodiment provided by the present invention, the screening element includes a second screening net 32 ​​and a grinding roller 33, and a screening opening is opened at the feeding end of the powder coating tube 2. At this time, the collecting chamber surrounds the powder coating tube 2, and the screening opening is rectangular. A plate-shaped bracket 34 is provided on each of the two opposite sides facing the collecting chamber, and a soft cloth (not shown in the figure) is provided on each of the other two sides facing the collecting chamber. The two soft cloths and the two brackets 34 form a rectangular structure. The second screening net 32 ​​covers the top opening of the rectangular structure, and the screening opening is the bottom opening of the rectangular structure. In this way, the second screening net 32 ​​is located above the screening opening, and the space between the edge of the second screening net 32 ​​and the powder coating tube 2 is closed by the rectangular structure formed by the bracket 34 and the soft cloth. Specifically, the frame portion 321 is movably connected to the bracket 34, and the other two sides of the frame portion 321 are connected to the soft cloth. The frame portion 321 can move both radially and axially relative to the powder coating tube 2. In addition, the powder at the lower end of the collecting chamber is sent to the high end through a separate conveying channel such as a spiral auger 31. The screening port is connected to the collecting chamber. A first through hole is provided on the surface of the bracket 34. A positioning pin 341 is slidably inserted in the first through hole. A plurality of connecting rods 35 parallel to each other are provided on both sides of the frame portion 321. One end of the connecting rod 35 is rotatably connected to the frame portion 321, and the other end of the connecting rod 35 is rotatably connected to the bracket 34. A second through hole 3211 is provided on the surface of the second screening net 32. The two through holes 3211 are on the same straight line with the axis of the first through hole, and a rack is provided on each opposite side of the surface of the frame portion 321. A moving block 342 is movably connected to each of the two brackets 34. The two ends of the grinding roller 33 are rotatably connected to the two moving blocks 342. The grinding roller 33 fits the surface of the second screening net 32. Gears are provided at both ends of the grinding roller 33, and the gears are meshed with the racks one by one. A driving member such as a micro motor is provided on the moving block 342 to drive the grinding roller 33 to rotate.

[0036] In this embodiment, there is still a small gap between the edge of the frame portion 321 and the bracket 34. In an optional embodiment, the gap can be closed by another soft cloth. The soft cloth is used because the frame portion 321 needs to move, and the soft cloth can adapt to multi-directional movement.

[0037] Preferably, Figure 2As shown, the discharge port of the spiral auger 31 is located at the upper position of the high end of the collecting chamber, so that when the powder coating tube 2 rotates, the second screen 32 is intermittently located directly below the discharge port of the spiral auger 31. The discharge port of the spiral auger 31 should be provided with a switch mechanism, and the switch mechanism is matched with the driving member of the powder coating tube 2, so that each time the second screen 32 on the powder coating tube 2 passes through the discharge port of the spiral auger 31, it is automatically opened and closed after the second screen 32 leaves. At this time, the second screen 32 is located on the upper side of the powder inlet channel of the powder coating tube 2 to prevent excessive powder from flowing out of the second screen 32. The distance between the second through hole 3211 and the first through hole is less than the length of the positioning pin 341, so that the positioning pin 341 can move between the first through hole and the second through hole 3211 (in the coating During the rotation of the powder barrel 2, it reciprocates under the action of gravity) but will not disengage from the first through hole, and when one end of the positioning pin 341 is fully inserted into the first through hole, the other end of the positioning pin 341 will not enter the second through hole 3211, and the movement trajectory of the moving block 342 on the bracket 34 is the movement trajectory of the two ends of the grinding roller 33 on the surface of the bracket 34 when rolling on the second screening net 32. A plurality of limit blocks 343 are provided on the surface of the bracket 34, and the limit blocks 343 are arranged in one of the rotation directions of the connecting rod 35. The limit blocks 343 are arranged one by one beside the plurality of connecting rods 35 to limit the unidirectional rotation of the connecting rod 35. A torsion spring is provided on the connecting rod 35 to reset the connecting rod 35 after rotation, and the connecting rod 35 can generate vibration by continuous rotation and resetting.

[0038] Specifically, when the food and powder in the powder coating tube 2 slide to the position of the first screening net 21 together, the powder leaks from the first screening net 21 into the feed port of the spiral auger 31, and the spiral auger 31 brings the powder into the upper part of the feeding end of the powder coating tube 2. When the second screening net 32 ​​rotates to the discharge port position of the spiral auger 31, the powder falls on the second screening net 32 ​​on the surface of the powder coating tube 2, and then the driving member drives the grinding roller 33 to rotate, and the gear on the grinding roller 33 rotates on the rack on the surface of the second screening net 32. The surface pushes forward, and the connecting rods 35 on both sides of the second screen 32 start to rotate, causing the second screen 32 to move horizontally forward and downward until the rack is separated from the gear. At this time, the connecting rod 35 rebounds and resets under the action of the torsion spring, causing the second screen 32 to reset, and the rack on the second screen 32 contacts the gear again. This repetition causes the second screen 32 to vibrate, and the larger wet particles on the surface of the second screen 32 remain on the second screen 32. The qualified powder enters the powder coating drum 2 for coating. The rotation continues, and the large particles on the second screening net 32 ​​roll down to the surface of the grinding roller 33. When the grinding roller 33 moves to the end of the screening net portion 322, it starts to rotate in the opposite direction. The driving member drives the grinding roller 33 to rotate in the opposite direction, and the gear on the grinding roller 33 rotates on the rack to push the second screening net 32 ​​backward. At this time, the connecting rod 35 cannot rotate backward due to the limit block 343, so that the rack cannot avoid the gear. The gear starts to rotate on the rack, thereby driving the moving block 342 to move, and the grinding roller 33 starts to move on the second screening net. The surface of 32 rolls forward, pressing the large particles on the surface of the second screening net 32 ​​into the powder coating drum 2. At this time, the second screening net 32 ​​begins to tilt downward, and the positioning pin 341 on the bracket 34 slides into the second through hole 3211 under the action of gravity to lock the second screening net 32. At this time, the connecting rod 35 cannot rotate, and the rack cannot avoid the gear. The gear begins to rotate on the rack, thereby driving the moving block 342 to move and make the grinding roller 33 return to its initial position. The powder coating drum 2 repeats the above movement during the rotation process to perform screening and grinding.

[0039] In the above embodiment of the present invention, during the swinging of the connecting rod 35 , due to the continuous avoidance of the rack, the grinding roller 33 still has a weak relative movement function relative to the rack, but at a slower speed.

[0040] The beneficial effect of the embodiment of the present invention is that the large particles on the surface of the second sieve mesh 32 are squeezed and crushed by the grinding roller 33 so that no large particles remain on the surface of the second sieve mesh 32, thereby improving the utilization rate of the powder.

[0041] Since the second screening net 32 ​​is in a rotating state and the discharge port of the spiral auger 31 is located at a specific position above the feeding end of the powder coating tube 2, the second screening net 32 ​​does not screen the powder for a period of time before reaching the discharge port, and the powder is directly poured onto the surface of the second screening net 32 ​​for screening. A large amount of powder falls from the surface of the second screening net 32, which reduces the screening efficiency.

[0042] In another embodiment provided by the present invention, the feeding end of the powder coating tube 2 is sleeved with a storage tube 4, the powder coating tube 2 passes through the storage tube 4, and an annular cavity is formed between the inner wall of the storage tube 4 and the outer wall of the powder coating tube 2. The discharge port of the spiral auger 31 is connected to the annular cavity, and the second screening net 32 ​​is located inside the annular cavity. A scraper 5 is fixed to the outer surface of the powder coating tube 2. In the rotation direction, the scraper 5 is located downstream of the second screening net 32, that is, the second screening net 32 ​​first passes through the discharge port of the spiral auger 31, and then the scraper 5 passes through, leaving a gap between the scraper 5 and the annular cavity.

[0043] Preferably, in order to ensure that the scraper 5 can completely scrape up the powder in the annular cavity, the edge portion of the scraper 5 should be made of elastic rubber material, so that the rubber portion can completely fit the inner wall of the storage tube 4 to scrape up the powder as completely as possible, and the scraper 5 fits one end of the second screening mesh 32 at the initial position so that the powder on the surface of the scraper 5 will not fall from the gap between the scraper 5 and the second screening mesh 32 when sliding onto the second screening mesh 32, and the initial movement direction of the second screening mesh 32 when vibrating is the direction away from the scraper 5. The second screening mesh 32 will impact the surface of the scraper 5 when vibrating, which accelerates the speed at which the powder on the scraper 5 slides down and improves the screening efficiency. At the same time, the scraper 5 limits the second screening mesh 32, which has the same effect as the limit block 343 and is used instead of the limit block 343.

[0044] Specifically, when the powder in the powder coating tube 2 leaks from the first screening net 21 and enters the feed port of the spiral auger 31, the spiral auger 31 brings the powder into the annular cavity. The scraper 5 on the powder coating tube 2 rotates in the annular cavity, and the scraper 5 picks up the powder. When the powder and the second screening net 32 ​​gradually face upward under the rotation of the powder coating tube 2, the powder enters the second screening net 32 ​​and is screened. The large particles of powder remain on the second screening net 32 ​​and are ground by the grinding roller 33. The unground powder and the powder scattered from the second screening net 32 ​​are The powder falls into the annular cavity, the powder coating cylinder 2 continues to rotate, the scraper 5 scrapes the powder again, and the screening is repeated continuously. Finally, all the large particles of powder in the annular cavity are ground, and the recovery rate of the powder is high. When the second screening net 32 ​​rotates upward, the scraper 5 always pushes the powder to one side of the second screening net 32, so that the surface of the second screening net 32 ​​has powder when it reaches the angle for feeding, thereby improving the screening efficiency. The annular cavity of the storage cylinder 4 is relatively closed, and there is no dust diffusion during the screening process, which reduces pollution.

[0045] In another embodiment provided by the present invention, it further includes a movable plate 6, which is movably connected to the surface of the scraper 5. An electric push rod 51 is provided on the surface of the scraper 5, and the output end of the electric push rod 51 is fixed on the surface of the scraper 5 to drive the movable plate 6 to move linearly.

[0046] Specifically, since the powder coating tube 2 is set at an angle, when the scraper 5 scrapes up the powder, the powder will also slide downward on the surface of the scraper 5, so that the powder will be in a lower position of the second screening net 32 ​​when it falls on the second screening net 32, thereby reducing the screening area of ​​the second screening net 32. During operation, when the scraper 5 rotates to a horizontal position, the electric push rod 51 pulls the movable plate 6 to move and scrapes the powder on the surface of the movable plate 6 upward along the surface of the scraper 5, so that the powder slides to a position above the second screening net 32, so that the powder evenly enters the surface of the second screening net 32 ​​for screening, thereby improving the screening efficiency.

[0047] In another embodiment provided by the present invention, the second screening mesh 32 includes a frame portion 321 and a screening mesh portion 322, and the screening mesh portion 322 is slidably connected to the frame portion 321. For example, a slide groove is provided on the inner side of the frame portion 321, and the screening mesh portion 322 is slidably connected to the slide groove through a hard ring on its edge. The direction of the sliding connection is perpendicular to the direction of the screening mesh portion 322, such as Figure 5 The screen mesh portion 322 slides in the vertical direction. At the same time, an elastic member is provided on the surface of the screen mesh portion 322 . One end of the elastic member is fixed on the frame portion 321 . The elastic member enables the screen mesh portion 322 to have an initial position on the frame portion 321 .

[0048] Specifically, when the grinding roller 33 crushes the powder on the surface of the second screening mesh 32 for a long time, it is easy to cause the second screening mesh 32 to deform, resulting in a reduction in the grinding effect, and it will also cause some wet powder to adhere to the second screening mesh 32 for a long time, causing quality problems. The rack on the second screening mesh 32 is arranged on the frame portion 321 so that the screening mesh portion 322 does not affect the coordination of the gear rack when it moves on the frame portion 321. The screening mesh portion 322 is in contact with the surface of the grinding roller 33. During operation, when the grinding roller 33 encounters harder particles when rolling on the surface of the screening mesh portion 322, the screening mesh portion 322 can compress the elastic part to slide and avoid to prevent the second screening mesh 32 from being compressed and deformed.

[0049] Another embodiment of the present invention further provides a drum powder coating machine, comprising the above-mentioned screening mechanism.

[0050] In another embodiment provided by the present invention, a feeding conveyor mesh belt 6 is provided on one side of the feeding end of the powder coating tube 2, and the feeding conveyor mesh belt 6 includes a horizontal section and an inclined section. One end of the inclined section of the feeding conveyor mesh belt 6 extends into the powder coating tube 2, and the feeding conveyor mesh belt 6 is used to feed the food into the powder coating tube 2.

[0051] Another embodiment provided by the present invention also includes a pre-dusting mechanism, which is used to pre-dusting the surface of the feeding conveyor mesh belt 6 so that a layer of powder is laid on the surface of the feeding conveyor mesh belt 6. The food is dusted once before entering the flour coating cylinder 2 to improve the dusting effect.

[0052] Another embodiment provided by the present invention also includes a pre-powdering mechanism, which includes a vibrating screen, and the discharge port of the vibrating screen is above the conveying surface of the loading conveyor mesh belt 6. The vibrating screen shakes the powder onto the surface of the working loading conveyor mesh belt 6 so that the powder is evenly laid on the surface of the loading conveyor mesh belt 6.

[0053] The above description is merely illustrative of certain exemplary embodiments of the present invention. It goes without saying that those skilled in the art will be able to modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and description are illustrative in nature and should not be construed as limiting the scope of protection of the claims.

Claims

1. A screening mechanism comprising a powder coating drum driven to rotate, wherein both ends of the powder coating drum are open and arranged obliquely, wherein the higher end of the powder coating drum is a feeding end and the lower end of the powder coating drum is a discharging end, wherein: The powder coating tube is provided with a first screening net at the discharge end, and a collecting cavity is formed on the outside of the powder coating tube, and the material screened by the first screening net enters the collecting cavity; The device further comprises a conveying assembly for screening the powder at the bottom of the collecting chamber and delivering it to the feeding end of the powder coating tube. The conveying assembly comprises a conveying member and a screening member. The feeding port of the conveying member is in communication with the bottom of the collecting chamber, and the discharging port of the conveying member is in communication with the upper portion of the collecting chamber near the feeding end of the powder coating tube. The screening member is arranged in the circumferential direction of the feeding end of the powder coating tube and enables communication between the inside and the outside of the powder coating tube. The screening component includes a second screening net and a grinding roller, a screening port is provided at the feeding end of the powder coating tube, the screening port is communicated with the collecting chamber, brackets are provided on both sides of the screening port, a first through hole is provided on the surface of the bracket, a positioning pin is slidably inserted in the first through hole, a plurality of connecting rods parallel to each other are provided on both sides of the second screening net, one end of the connecting rod is rotatably connected to the second screening net, and the other end of the connecting rod is rotatably connected to the bracket, a second through hole is provided on the surface of the second screening net, the axis of the second through hole and the first through hole are in the same straight line, a rack is provided on the surface of the second screening net, and two brackets are movably connected to each other. A moving block, both ends of the grinding roller are rotatably connected to the two moving blocks, the grinding roller is in contact with the surface of the second screening net, gears are provided at both ends of the grinding roller, the gears are meshed with the rack, and a driving member is provided on the moving block for driving the grinding roller to rotate, the feeding end of the powder coating tube is sleeved with a storage tube, the powder coating tube passes through the storage tube, an annular cavity is formed between the inner wall of the storage tube and the outer wall of the powder coating tube, the discharge port of the spiral auger is connected with the storage tube, the second screening net is inside the annular cavity, a scraper is fixed to the outer surface of the powder coating tube, the scraper is on one side of the second screening net, and a gap is left between the scraper and the annular cavity.

2. The screening mechanism according to claim 1, characterized in that: The scraper surface is provided with a movable plate, which is movably connected to the scraper surface. The scraper surface is provided with an electric push rod, and the output end of the electric push rod is fixed on the scraper surface to drive the movable plate to move linearly.

3. The screening mechanism according to claim 1, characterized in that: The second screening net includes a frame portion and a screening net portion. The screening net portion is slidably connected to the frame portion. An elastic member is provided on the surface of the screening net portion. One end of the elastic member is fixed to the frame portion.

4. A roller powder coating machine, characterized in that: The invention comprises the screening mechanism according to any one of claims 1 to 3.

5. The drum powder coating machine according to claim 4, characterized in that: A feeding conveyor mesh belt is provided on one side of the feeding end of the powder coating tube. The feeding conveyor mesh belt includes a horizontal section and an inclined section. One end of the inclined section of the feeding conveyor mesh belt extends into the powder coating tube.

6. The drum powder coating machine according to claim 5, characterized in that: It also includes a pre-dusting mechanism, which is used to pre-dusting the food on the feeding conveyor belt.

7. The drum powder coating machine according to claim 6, characterized in that: The pre-powder loading mechanism includes a vibrating screen, and the discharge port of the vibrating screen is located above the conveying surface of the feeding conveying mesh belt.

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