Preparation apparatus and method for polyester powder coating

Abstract

The application discloses a polyester powder coating preparation device and a preparation method, and mainly realizes automatic seamless switching of mixing and discharging processes through forward and reverse switching of a single driving source and cooperation of a one-way transmission member; when rotating forward, only stirring is ensured to ensure sufficient homogeneity; when rotating reversely, the one-way transmission member is locked to drive the built-in spiral shaft to forcibly push materials; not only is the cost greatly reduced with an extremely simple structure, but also the problem of bridging blockage and dead angle residual of polyester powder coating caused by static electricity and moisture absorption is completely solved by using the driving thrust of the central screw, high emptying rate and zero cross-contamination are realized, and high uniformity between batches and production continuity are ensured; in addition, dustproof adaptation is carried out for the improved structure, and normal operation of the equipment is ensured.

Description

Technical Field

[0001] This invention relates to coating manufacturing equipment, and more particularly to equipment and methods for preparing polyester powder coatings. Background Technology

[0002] Polyester powder coatings, with their excellent outdoor weather resistance (UV resistance, non-chalking), rich decorative effects (high gloss, matte, metallic texture, wood grain), and environmentally friendly and non-toxic properties, have become the preferred surface coating material for architectural aluminum profiles (doors, windows, curtain walls), outdoor metal facilities (railings, light poles), household appliance housings (air conditioners, refrigerators), automotive parts (wheel hubs, chassis), and general metal furniture. They are especially suitable for all metal product scenarios that require long-term resistance to wind and sun and have high requirements for aesthetics.

[0003] The manufacturing process of polyester powder coatings generally involves the following steps: raw material premixing → melt extrusion → sheeting and cooling → coarse crushing → fine grinding → screening and packaging. The premixing of raw materials requires mixing the granular materials and powders evenly before feeding them into the extruder for extrusion. The mixing process improves the uniformity of the materials, resulting in a relatively uniform texture during melt extrusion.

[0004] Traditional equipment either uses two separate devices (CN201520339531.3) to achieve mixing and feeding, or integrates them into one device (CN201821770226.X). However, these devices are equipped with two separate power systems to independently drive mixing and feeding. Firstly, the additional power system increases costs. Secondly, when switching from "mixing" to "discharging", it is usually necessary to stop the machine, turn off the mixing, and then turn on the discharge screw. The mixing and feeding processes are relatively separated, and bridging is very likely to occur during feeding. Summary of the Invention

[0005] In view of the shortcomings of existing technologies, such as high cost of stirring and feeding separation structure and easy bridging problem, this invention provides a preparation equipment and preparation method for polyester powder coating.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: Equipment for preparing polyester powder coatings, comprising a tank for mixing and feeding powder into an extruder, and further comprising: A drive unit, located at the top of the tank, is used to provide power for forward and reverse rotation; The discharge cylinder is located at the center of the bottom of the tank. The bottom of the tank is designed as an arc-shaped structure with a lower center, so that the material is guided into the discharge cylinder in the middle after falling. The stirring cylinder is installed inside the tank, and its top is connected to the drive device. It has a hollow structure and its side walls are equipped with stirring blades. The feeding shaft is rotatably located inside the mixing drum, and its lower part is equipped with spiral feeding blades located inside the discharge cylinder. A one-way transmission component is installed between the mixing drum and the feeding shaft to enable one-way transmission between the discharge drum and the feeding shaft.

[0007] Preferably, the one-way transmission component is a one-way actuator or a ratchet and pawl assembly, the two parts of which are fixedly connected to the feeding shaft and the mixing cylinder, respectively.

[0008] Preferably, the one-way clutch is a roller-type one-way bearing or a wedge-type one-way clutch.

[0009] Preferably, the side wall of the mixing tank is fixed with an annular top plate located at the bottom end of the mixing cylinder. An annular bottom plate is fixed on the feeding shaft and abuts against the annular top plate. The annular bottom plate and the annular top plate divide the internal space of the mixing tank into an upper region and a lower region. Both the annular bottom plate and the annular top plate are provided with a number of circular drop holes arranged in a circular array. When mixing alone, the upper and lower layers of circular drop holes are completely misaligned and stop feeding. When mixing and feeding, the feeding shaft drives the annular bottom plate to rotate. When the two layers of circular drop holes overlap, feeding begins and the spiral blades convey the material downward.

[0010] Preferably, the annular top plate has a cylindrical column in the middle that extends upward and rotates with the mixing cylinder. The top of the column is equipped with a first labyrinth seal. The side wall of the annular cylinder is equipped with an inverted L-shaped mounting bracket that extends to the gap between the cylindrical column and the tank. The mixing blades are mounted on the mounting bracket. The height of the first labyrinth seal is higher than the height of the top surface of the material.

[0011] Preferably, the mixing cylinder and the feeding shaft are rotated together by multiple bearings, and a second labyrinth seal is provided at the bottom of the mixing cylinder.

[0012] Preferably, a Hall sensor is installed on the discharge cylinder and a magnet is embedded in the feeding shaft. The Hall sensor determines the angular position of the feeding shaft and records the number of rotations of the feeding shaft based on the magnetic field strength of the magnet.

[0013] Preferably, the tank is equipped with a feed inlet, which is connected to a suction machine via a pipe, and the raw materials are sucked into the tank by the suction machine.

[0014] A method for preparing polyester powder coatings includes the following steps: S1, material suction, which uses a material suction machine to suck material into the tank; S2, stirring: the stirring cylinder is driven to rotate by the driving device, while the feeding shaft remains unchanged. At this time, the circular dropping holes on the annular top plate and the annular bottom plate are completely misaligned, and the material is in the upper area of ​​the tank. S3, feeding. This step includes a first scheme and a second scheme. First scheme: After mixing, the drive device rotates in the opposite direction at a set angle so that the two layers of circular dropping holes completely overlap. Then, the reverse rotation is stopped and a stop time is set. The speed of the feeding shaft is set according to the required feeding speed and driven in the opposite direction by the drive device so that the spiral feeding shaft feeds the mixed material into the extruder. The end position of each feeding is set at the position where the two layers of circular dropping holes are completely misaligned. Second scheme: After mixing, the drive device rotates directly in the opposite direction and the speed of the feeding shaft is set according to the required feeding speed. The spiral feeding shaft is driven in the opposite direction by the drive device so that the mixed material is fed into the extruder. The end position of each feeding is set at the position where the two layers of circular dropping holes are completely misaligned. S4, Extrusion: The material is melted and extruded through an extruder, then cooled and shaped into sheets; S5, Crushing: The sheet material cooled and formed in S4 is coarsely crushed, finely crushed, ground, and sieved to obtain the finished product; In step S3, the angle is determined by a Hall sensor.

[0015] Preferably, the gap width between the circular drop holes on the annular top plate and the annular bottom plate is greater than the diameter of the circular drop holes to provide redundant space at the end of the material feeding position.

[0016] Compared with the prior art, the advantages of this invention are as follows: This application mainly achieves seamless automation of the mixing and feeding processes by switching between forward and reverse rotation of a single drive source in conjunction with a unidirectional transmission component: during forward rotation, only stirring is performed to ensure sufficient homogenization, while during reverse rotation, the unidirectional transmission component locks and drives the built-in spiral shaft to force the material to be pushed. This not only significantly reduces costs with a minimalist structure, but also completely solves the problem of bridging, clogging, and dead-angle residue caused by static electricity and moisture absorption in polyester powder coatings by utilizing the active thrust of the central spiral. This achieves high air evacuation rate and zero cross-contamination, ensuring high uniformity and production continuity between batches. In addition, dustproof adaptation has been carried out for the improved structure to ensure the normal operation of the equipment. Attached Figure Description

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and preferred embodiments. However, those skilled in the art will understand that these drawings are drawn only for the purpose of explaining the preferred embodiments and therefore should not be construed as limiting the scope of the invention. Furthermore, unless specifically indicated, the drawings are only schematic representations of the composition or structure of the described objects and may contain exaggerated depictions, and the drawings are not necessarily drawn to scale.

[0018] Figure 1 This is a perspective view of the present application; Figure 2 This is a cross-sectional view of the tank in this application; Figure 3A three-dimensional view of the tank's interior and drive system; Figure 4 Exploded view of the tank interior and drive unit; Figure 5 Exploded view of the tank interior and drive unit; In the diagram: 10, drive unit; 20, reducer; 30, tank body; 301, upper area; 302, lower area; 40, suction feeder; 50, mixing cylinder; 501, mounting frame; 5011, mixing blades; 60, discharge shaft; 70, one-way transmission component; 801, annular top plate; 8011, cylindrical column; 802, annular bottom plate; 90, discharge cylinder; 901, spiral discharge blades; 01, first labyrinth seal; 02, second labyrinth seal. Detailed Implementation

[0019] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Those skilled in the art will appreciate that these descriptions are merely descriptive and exemplary and should not be construed as limiting the scope of protection of the present invention.

[0020] It should be noted that similar labels in the following figures indicate similar items; therefore, once an item is defined in one figure, it may not be further defined and explained in subsequent figures. Example

[0021] This embodiment mainly describes the title of the equipment for preparing polyester powder coatings, as follows: Equipment for preparing polyester powder coatings, such as Figure 1-5 As shown, it includes a tank 30 for mixing and feeding powder into an extruder, and also includes: The drive unit 10 is located on the top of the tank 30 and is used to provide forward and reverse rotation power. The drive unit 10 adopts a combination of a bidirectional motor and a reducer 20. The motor adopts a servo motor to increase the accuracy of feeding. The discharge cylinder 90 is located at the bottom of the tank body 30; The stirring cylinder 50 is installed inside the tank 30, and its top is connected to the drive device 10. It has a hollow structure and its side wall is provided with stirring blades 5011. The top of the stirring cylinder 50 is fixed to the output end of the reducer 20 by sleeve connection and welding. A feeding shaft 60 is rotatably mounted inside the mixing cylinder 50. Its lower part is equipped with spiral feeding blades 901 located within a discharge cylinder 90. The spiral feeding blades 901 and the discharge cylinder 90 are fitted with a small gap to prevent a large amount of material from falling into the extruder through the gap. The shaft includes a tank 30 for mixing and feeding powder into the extruder, and also includes: The drive unit 10 is located on the top of the tank 30 and is used to provide forward and reverse rotation power. The drive unit 10 adopts a combination of a bidirectional motor and a reducer 20. The motor adopts a servo motor to increase the accuracy of feeding. The discharge cylinder 90 is located at the bottom of the tank body 30; The stirring cylinder 50 is installed inside the tank 30, and its top is connected to the drive device 10. It has a hollow structure and its side wall is provided with stirring blades 5011. The top of the stirring cylinder 50 is fixed to the output end of the reducer 20 by sleeve connection and welding. The feeding shaft 60 is rotatably disposed inside the mixing cylinder 50. The lower part of the shaft is provided with a spiral feeding blade 901 located in the discharge cylinder 90. The spiral feeding blade 901 and the discharge cylinder 90 are fitted with a small gap to prevent a large amount of material from falling into the extruder through the gap. A one-way transmission component 70, positioned between the mixing drum 50 and the feeding shaft 60, enables unidirectional transmission between the discharge drum 90 and the feeding shaft 60. This solution primarily utilizes the forward and reverse switching of a single drive source in conjunction with the one-way transmission component 70 to achieve seamless automation of the mixing and feeding processes: during forward rotation, only stirring ensures sufficient homogenization; during reverse rotation, the one-way transmission component 70 locks, driving the built-in spiral shaft to forcefully push the material. This not only significantly reduces costs with its minimalist structure (single motor, no complex control) but also completely solves the problems of bridging, clogging, and dead-angle residue caused by static electricity and moisture absorption in polyester powder coatings by utilizing the active thrust of the central spiral. This achieves high air evacuation rate and zero cross-contamination, ensuring high batch uniformity and production continuity.

[0022] Preferably, the one-way transmission component 70 is a one-way actuator or a ratchet-pawl assembly, with its two parts fixedly connected to the feeding shaft 60 and the mixing cylinder 50, respectively; the one-way actuator is a roller-type one-way bearing or a wedge-type one-way clutch. This solution provides two types of one-way transmission components 70. The one-way actuator has high precision, low noise, and good stability, making it suitable for high-precision, high-frequency, quiet, and continuous production. However, since the material in this application contains powder, a dustproof structure is required. The ratchet-pawl assembly has most of the performance weaknesses of the one-way actuator, but it has advantages such as resistance to extreme impacts and low cost. Furthermore, due to its larger internal clearance, it has a stronger dust resistance than the one-way actuator. However, in actual production, the one-way actuator is preferred, and a sealing structure is provided. It includes a tank 30, which is used to mix and feed the powder into the extruder, and also includes: The drive unit 10 is located on the top of the tank 30 and is used to provide forward and reverse rotation power. The drive unit 10 adopts a combination of a bidirectional motor and a reducer 20. The motor adopts a servo motor to increase the accuracy of feeding. The discharge cylinder 90 is located at the bottom of the tank body 30; The stirring cylinder 50 is installed inside the tank 30, and its top is connected to the drive device 10. It has a hollow structure and its side wall is provided with stirring blades 5011. The top of the stirring cylinder 50 is fixed to the output end of the reducer 20 by sleeve connection and welding. The feeding shaft 60 is rotatably disposed inside the mixing cylinder 50. The lower part of the shaft is provided with a spiral feeding blade 901 located in the discharge cylinder 90. The spiral feeding blade 901 and the discharge cylinder 90 are fitted with a small gap to prevent a large amount of material from falling into the extruder through the gap. A one-way transmission component 70, positioned between the mixing drum 50 and the feeding shaft 60, enables unidirectional transmission between the discharge drum 90 and the feeding shaft 60. This solution primarily utilizes the forward and reverse switching of a single drive source in conjunction with the one-way transmission component 70 to achieve seamless automation of the mixing and feeding processes: during forward rotation, only stirring ensures sufficient homogenization; during reverse rotation, the one-way transmission component 70 locks, driving the built-in spiral shaft to forcefully push the material. This not only significantly reduces costs with its minimalist structure (single motor, no complex control) but also completely solves the problems of bridging, clogging, and dead-angle residue caused by static electricity and moisture absorption in polyester powder coatings by utilizing the active thrust of the central spiral. This achieves high air evacuation rate and zero cross-contamination, ensuring high batch uniformity and production continuity.

[0023] Preferably, the one-way transmission component 70 is a one-way actuator or a ratchet-pawl assembly, with its two parts fixedly connected to the feeding shaft 60 and the mixing cylinder 50, respectively. The one-way actuator is either a roller-type one-way bearing or a wedge-type one-way clutch. This solution provides two types of one-way transmission components 70. The one-way actuator has high precision, low noise, and good stability, making it suitable for high-precision, high-frequency, quiet, and continuous production. However, since the material in this application contains powder, a dustproof structure is required. The ratchet-pawl assembly has most of the performance disadvantages compared to the one-way actuator, but it has the advantages of resistance to extreme impacts and low cost. In addition, due to its larger internal clearance, it has a stronger dust resistance than the one-way actuator. However, in actual production, the one-way actuator is preferred, and a sealing structure is provided accordingly.

[0024] In existing technologies that integrate mixing and feeding into the same mixing tank, the space inside the mixing tank is generally shared. This results in a mixing blind zone appearing in the anti-interference area of ​​the mixing tank due to the space reserved between the spiral blades and the mixing blades to prevent interference. To solve this problem, the following solution is adopted: an annular top plate 801 is fixed to the side wall of the mixing tank, and the annular top plate 801 is located at the bottom end of the mixing cylinder 50. An annular bottom plate 802 is fixed on the feeding shaft 60, which is close to the annular top plate 801. Preferably, the annular top plate 801 and the annular bottom plate 802 can be connected together. A raised ring and a groove matching the shape of the raised ring are respectively provided between the plates 802 for the raised ring to extend into. The annular bottom plate 802 and the annular top plate 801 divide the internal space of the mixing tank into an upper region 301 and a lower region 302. Both the annular bottom plate 802 and the annular top plate 801 are provided with several circular arrays of circular drop holes. When mixing alone, the upper and lower layers of circular drop holes are completely misaligned to stop the material from falling. When mixing and dropping material, the feeding shaft 60 drives the annular bottom plate 802 to rotate. When the two layers of circular drop holes overlap, the material begins to fall and the spiral blades convey the material downward. The material is isolated above and mixed by the annular top plate 801 and the annular bottom plate 802. When it is necessary to drop material, the annular bottom plate 802 rotates with the feeding shaft 60 so that the circular drop holes are aligned and the material falls. The structure is simple and achieves physical isolation of the material, so that the mixing and dropping complement each other and eliminates the mixing blind zone.

[0025] Since the raw materials in this application contain powder, dust is easily generated inside the can, which can significantly affect the bearings and one-way valves. Therefore, this application uses a labyrinth seal to prevent dust. In addition, to improve the dust prevention effect, the following specific solutions are adopted: First, a cylindrical column 8011 is provided in the middle of the annular top plate 801, which extends upward and rotates with the mixing cylinder 50. A first labyrinth seal 01 is provided at the top of the column. An inverted L-shaped mounting bracket 501 is provided on the side wall of the annular cylinder. The mounting bracket 501 extends to the gap between the cylindrical column 8011 and the tank 30, and the stirring blades 5011 are mounted on the mounting bracket 501. The height of the first labyrinth seal 01 is higher than the height of the top surface of the material. Since the bottom of the mixing cylinder 50 has an opening, if a sealing structure is directly installed there, the powder will come into direct contact with the sealing structure, which will undoubtedly increase the burden on the sealing structure. Therefore, this application uses the structure of the annular top plate 801 to provide an upwardly extending cylindrical column 8011 in the middle to raise the opening. During stirring, the amount of material added can be controlled to ensure that the material is below the top opening of the cylindrical column 8011, and a seal is installed at the opening to avoid direct contact between the material and the seal.

[0026] Secondly, the mixing drum 50 and the feeding shaft 60 are rotatably supported by multiple bearings, and a second labyrinth seal 02 is provided at the bottom of the mixing drum 50. This design further incorporates internal seals to increase the sealing strength and ensure that the one-way transmission component 70 and the internal bearings are not contaminated by dust.

[0027] Preferably, a Hall sensor is installed on the discharge cylinder 90, and a magnet is embedded in the feeding shaft 60. The Hall sensor determines the angular position of the feeding shaft 60 and records the number of rotations of the feeding shaft 60 based on the magnetic field strength of the magnet. The Hall sensor is mainly used to cooperate with the servo motor to position the annular top plate 801 and the annular bottom plate 802, ensuring that their relative positions are at the set positions at different stages.

[0028] Preferably, the tank 30 is equipped with a feed inlet, which is connected to a suction feeder 40 via a pipe. The raw materials are sucked into the tank 30 by the suction feeder 40. Since the raw materials are powders and granules, using the suction feeder 40 for feeding can isolate dust inside and avoid dust pollution in the workshop.

[0029] In existing technologies that integrate mixing and feeding into the same mixing tank, the space inside the mixing tank is generally shared. This results in a mixing blind zone appearing in the anti-interference area of ​​the mixing tank due to the space reserved between the spiral blades and the mixing blades to prevent interference. To solve this problem, the following solution is adopted: an annular top plate 801 is fixed to the side wall of the mixing tank, and the annular top plate 801 is located at the bottom end of the mixing cylinder 50. An annular bottom plate 802 is fixed on the feeding shaft 60, which is close to the annular top plate 801. Preferably, the annular top plate 801 and the annular bottom plate 802 can be connected together. A raised ring and a groove matching the shape of the raised ring are respectively provided between the plates 802 for the raised ring to extend into. The annular bottom plate 802 and the annular top plate 801 divide the internal space of the mixing tank into an upper region 301 and a lower region 302. Both the annular bottom plate 802 and the annular top plate 801 are provided with several circular arrays of circular drop holes. When mixing alone, the upper and lower layers of circular drop holes are completely misaligned to stop the material from falling. When mixing and dropping material, the feeding shaft 60 drives the annular bottom plate 802 to rotate. When the two layers of circular drop holes overlap, the material begins to fall and the spiral blades convey the material downward. The material is isolated above and mixed by the annular top plate 801 and the annular bottom plate 802. When it is necessary to drop material, the annular bottom plate 802 rotates with the feeding shaft 60 so that the circular drop holes are aligned and the material falls. The structure is simple and achieves physical isolation of the material, so that the mixing and dropping complement each other and eliminates the mixing blind zone.

[0030] Since the raw materials in this application contain powder, dust is easily generated inside the can, which can significantly affect the bearings and one-way valves. Therefore, this application uses a labyrinth seal to prevent dust. In addition, to improve the dust prevention effect, the following specific solutions are adopted: First, a cylindrical column 8011 is provided in the middle of the annular top plate 801, which extends upward and rotates with the mixing cylinder 50. A first labyrinth seal 01 is provided at the top of the column. An inverted L-shaped mounting bracket 501 is provided on the side wall of the annular cylinder. The mounting bracket 501 extends to the gap between the cylindrical column 8011 and the tank 30, and the stirring blades 5011 are mounted on the mounting bracket 501. The height of the first labyrinth seal 01 is higher than the height of the top surface of the material. Since the bottom of the mixing cylinder 50 has an opening, if a sealing structure is directly installed there, the powder will come into direct contact with the sealing structure, which will undoubtedly increase the burden on the sealing structure. Therefore, this application uses the structure of the annular top plate 801 to provide an upwardly extending cylindrical column 8011 in the middle to raise the opening. During stirring, the amount of material added can be controlled to ensure that the material is below the top opening of the cylindrical column 8011, and a seal is installed at the opening to avoid direct contact between the material and the seal.

[0031] Secondly, the mixing drum 50 and the feeding shaft 60 are rotatably supported by multiple bearings, and a second labyrinth seal 02 is provided at the bottom of the mixing drum 50. This design further incorporates internal seals to increase the sealing strength and ensure that the one-way transmission component 70 and the internal bearings are not contaminated by dust.

[0032] Preferably, a Hall sensor is installed on the discharge cylinder 90, and a magnet is embedded in the feeding shaft 60. The Hall sensor determines the angular position of the feeding shaft 60 and records the number of rotations of the feeding shaft 60 based on the magnetic field strength of the magnet. The Hall sensor is mainly used to cooperate with the servo motor to position the annular top plate 801 and the annular bottom plate 802, ensuring that their relative positions are at the set positions at different stages.

[0033] Preferably, the tank 30 is equipped with a feed inlet, which is connected to a suction feeder 40 via a pipe. The raw materials are sucked into the tank 30 by the suction feeder 40. Since the raw materials are powders and granules, using the suction feeder 40 for feeding can isolate dust inside and avoid dust pollution in the workshop. A one-way transmission component 70, positioned between the mixing drum 50 and the feeding shaft 60, enables unidirectional transmission between the discharge drum 90 and the feeding shaft 60. This solution primarily utilizes the forward and reverse switching of a single drive source in conjunction with the one-way transmission component 70 to achieve seamless automation of the mixing and feeding processes: during forward rotation, only stirring ensures sufficient homogenization; during reverse rotation, the one-way transmission component 70 locks, driving the built-in spiral shaft to forcefully push the material. This not only significantly reduces costs with its minimalist structure (single motor, no complex control) but also completely solves the problems of bridging, clogging, and dead-angle residue caused by static electricity and moisture absorption in polyester powder coatings by utilizing the active thrust of the central spiral. This achieves high air evacuation rate and zero cross-contamination, ensuring high batch uniformity and production continuity.

[0034] Preferably, the one-way transmission component 70 is a one-way actuator or a ratchet-pawl assembly, with its two parts fixedly connected to the feeding shaft 60 and the mixing cylinder 50, respectively. The one-way actuator is either a roller-type one-way bearing or a wedge-type one-way clutch. This solution provides two types of one-way transmission components 70. The one-way actuator has high precision, low noise, and good stability, making it suitable for high-precision, high-frequency, quiet, and continuous production. However, since the material in this application contains powder, a dustproof structure is required. The ratchet-pawl assembly has most of the performance disadvantages compared to the one-way actuator, but it has the advantages of resistance to extreme impacts and low cost. In addition, due to its larger internal clearance, it has a stronger dust resistance than the one-way actuator. However, in actual production, the one-way actuator is preferred, and a sealing structure is provided accordingly.

[0035] In existing technologies that integrate mixing and feeding into the same mixing tank, the space inside the mixing tank is generally shared. This results in a mixing blind zone appearing in the anti-interference area of ​​the mixing tank due to the space reserved between the spiral blades and the mixing blades to prevent interference. To solve this problem, the following solution is adopted: an annular top plate 801 is fixed to the side wall of the mixing tank, and the annular top plate 801 is located at the bottom end of the mixing cylinder 50. An annular bottom plate 802 is fixed on the feeding shaft 60, which is close to the annular top plate 801. Preferably, the annular top plate 801 and the annular bottom plate 802 can be connected together. A raised ring and a groove matching the shape of the raised ring are respectively provided between the plates 802 for the raised ring to extend into. The annular bottom plate 802 and the annular top plate 801 divide the internal space of the mixing tank into an upper region 301 and a lower region 302. Both the annular bottom plate 802 and the annular top plate 801 are provided with several circular arrays of circular drop holes. When mixing alone, the upper and lower layers of circular drop holes are completely misaligned to stop the material from falling. When mixing and dropping material, the feeding shaft 60 drives the annular bottom plate 802 to rotate. When the two layers of circular drop holes overlap, the material begins to fall and the spiral blades convey the material downward. The material is isolated above and mixed by the annular top plate 801 and the annular bottom plate 802. When it is necessary to drop material, the annular bottom plate 802 rotates with the feeding shaft 60 so that the circular drop holes are aligned and the material falls. The structure is simple and achieves physical isolation of the material, so that the mixing and dropping complement each other and eliminates the mixing blind zone.

[0036] Since the raw materials in this application contain powder, dust is easily generated inside the can, which can significantly affect the bearings and one-way valves. Therefore, this application uses a labyrinth seal to prevent dust. In addition, to improve the dust prevention effect, the following specific solutions are adopted: First, a cylindrical column 8011 is provided in the middle of the annular top plate 801, which extends upward and rotates with the mixing cylinder 50. A first labyrinth seal 01 is provided at the top of the column. An inverted L-shaped mounting bracket 501 is provided on the side wall of the annular cylinder. The mounting bracket 501 extends to the gap between the cylindrical column 8011 and the tank 30, and the stirring blades 5011 are mounted on the mounting bracket 501. The height of the first labyrinth seal 01 is higher than the height of the top surface of the material. Since the bottom of the mixing cylinder 50 has an opening, if a sealing structure is directly installed there, the powder will come into direct contact with the sealing structure, which will undoubtedly increase the burden on the sealing structure. Therefore, this application uses the structure of the annular top plate 801 to provide an upwardly extending cylindrical column 8011 in the middle to raise the opening. During stirring, the amount of material added can be controlled to ensure that the material is below the top opening of the cylindrical column 8011, and a seal is installed at the opening to avoid direct contact between the material and the seal.

[0037] Secondly, the mixing drum 50 and the feeding shaft 60 are rotatably supported by multiple bearings, and a second labyrinth seal 02 is provided at the bottom of the mixing drum 50. This design further incorporates internal seals to increase the sealing strength and ensure that the one-way transmission component 70 and the internal bearings are not contaminated by dust.

[0038] Preferably, a Hall sensor is installed on the discharge cylinder 90, and a magnet is embedded in the feeding shaft 60. The Hall sensor determines the angular position of the feeding shaft 60 and records the number of rotations of the feeding shaft 60 based on the magnetic field strength of the magnet. The Hall sensor is mainly used to cooperate with the servo motor to position the annular top plate 801 and the annular bottom plate 802, ensuring that their relative positions are at the set positions at different stages.

[0039] Preferably, the tank 30 is equipped with a feed inlet, which is connected to a suction feeder 40 via a pipe. The raw materials are sucked into the tank 30 by the suction feeder 40. Since the raw materials are powders and granules, using the suction feeder 40 for feeding can isolate dust inside and avoid dust pollution in the workshop. Example

[0040] This embodiment mainly describes the preparation method of polyester powder coating, as follows: A method for preparing polyester powder coatings includes the following steps: S1, material suction, which uses a material suction machine to suck material into the tank; S2, stirring: the stirring cylinder is driven to rotate by the driving device, while the feeding shaft remains unchanged. At this time, the circular dropping holes on the annular top plate and the annular bottom plate are completely misaligned, and the material is in the upper area of ​​the tank. S3, Feeding: This step includes a first scheme and a second scheme. First scheme: After mixing, the drive device rotates in the opposite direction at a set angle to ensure the two layers of circular discharge holes completely overlap. Then, it stops rotating in the opposite direction and sets a stop time. The speed of the feeding shaft is then set according to the required feeding speed, and the drive device drives it in the opposite direction, causing the spiral feeding shaft to feed the mixed material into the extruder. The end position of each feeding is set at a position where the two layers of circular discharge holes are completely misaligned. Second scheme: After mixing, the drive device directly rotates in the opposite direction, and the speed of the feeding shaft is set according to the required feeding speed. The drive device drives it in the opposite direction, causing the spiral feeding shaft to feed the mixed material into the extruder. The end position of each feeding is set at a position where the two layers of circular discharge holes are completely misaligned. The first scheme adds a control step, allowing the material to fall for a period after mixing before starting spiral feeding to avoid the initial window period affecting feeding accuracy. The second scheme does not include this control. Therefore, if the second scheme is adopted during manufacturing, the area of ​​the feeding holes must be greater than the cross-sectional area of ​​the effective discharge channel. This ensures sufficient material falls during the rotation of the annular base plate for the spiral blades to convey downwards. S4, Extrusion: The material is melted and extruded through an extruder, then cooled and shaped into sheets; S5, Crushing: The sheet material cooled and formed in S4 is coarsely crushed, finely crushed, ground, and sieved to obtain the finished product; In step S3, the angle is determined by a Hall sensor.

[0041] Preferably, the gap width between the circular drop holes on the annular top plate and the annular bottom plate is greater than the diameter of the circular drop holes to provide redundant space at the end of the material feeding position. This solution provides positioning redundancy, providing a large space for closing the circular drop holes. Even if there is a small error in the Hall sensor or a control error caused by inertia, the circular drop holes will still be closed. Adding new material to the upper space serves as an isolation function, preventing unmixed material in the upper space from falling into the mixed material in the lower space under such circumstances.

[0042] The above two embodiments provide a detailed description of the preparation equipment and method for polyester powder coatings provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the present invention and its core ideas. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. Equipment for preparing polyester powder coatings, comprising a tank for mixing and feeding powder into an extruder, characterized in that, Also includes: A drive unit, located at the top of the tank, is used to provide power for forward and reverse rotation; The discharge cylinder is located at the bottom of the tank. The stirring cylinder is installed inside the tank, and its top is connected to the drive device. It has a hollow structure and its side walls are equipped with stirring blades. The feeding shaft is rotatably located inside the mixing drum, and its lower part is equipped with spiral feeding blades located inside the discharge cylinder. A one-way transmission component is installed between the mixing drum and the feeding shaft to enable one-way transmission between the discharge drum and the feeding shaft.

2. The equipment for preparing polyester powder coating according to claim 1, characterized in that, The one-way transmission component is a one-way device or a ratchet and pawl assembly, the two parts of which are fixedly connected to the feeding shaft and the mixing cylinder, respectively.

3. The equipment for preparing polyester powder coating according to claim 2, characterized in that, The one-way clutch is either a roller-type one-way bearing or a wedge-type one-way clutch.

4. The equipment for preparing polyester powder coating according to claim 1, characterized in that, The side wall of the mixing tank is fixed with an annular top plate located at the bottom end of the mixing cylinder. An annular bottom plate is fixed on the feeding shaft and abuts against the annular top plate. The annular bottom plate and the annular top plate divide the internal space of the mixing tank into an upper region and a lower region. Both the annular bottom plate and the annular top plate are provided with several circular arrays of circular drop holes. When mixing alone, the upper and lower layers of circular drop holes are completely misaligned and stop feeding. When mixing and feeding, the feeding shaft drives the annular bottom plate to rotate. When the two layers of circular drop holes overlap, feeding begins and the spiral blades convey the material downward.

5. The equipment for preparing polyester powder coating according to claim 4, characterized in that, A cylindrical column is provided in the middle of the annular top plate, which extends upward and rotates with the mixing cylinder. A first labyrinth seal is provided at the top of the column. An inverted L-shaped mounting bracket is provided on the side wall of the annular cylinder. The mounting bracket extends to the gap between the cylindrical column and the tank body, and the stirring blades are set on the mounting bracket. The height of the first labyrinth seal is higher than the height of the top surface of the material.

6. The equipment for preparing polyester powder coating according to claim 1, characterized in that, The mixing drum and the feeding shaft are rotated together by multiple bearings, and a second labyrinth seal is provided at the bottom of the mixing drum.

7. The equipment for preparing polyester powder coating according to claim 1, characterized in that, A Hall sensor is installed on the discharge cylinder, and a magnet is embedded in the feeding shaft. The Hall sensor determines the angular position of the feeding shaft and records the number of rotations of the feeding shaft based on the magnetic field strength of the magnet.

8. The equipment for preparing polyester powder coating according to claim 1, characterized in that, The tank is equipped with a feed inlet, which is connected to a suction machine via a pipe. The raw materials are sucked into the tank by the suction machine.

9. A method for preparing polyester powder coatings, characterized in that, Includes the following steps, S1, material suction, which uses a material suction machine to suck material into the tank; S2, stirring: the stirring cylinder is driven to rotate by the driving device, while the feeding shaft remains unchanged. At this time, the circular dropping holes on the annular top plate and the annular bottom plate are completely misaligned, and the material is in the upper area of ​​the tank. S3, feeding. This step includes a first scheme and a second scheme. First scheme: After mixing, the drive device rotates in the opposite direction at a set angle so that the two layers of circular dropping holes completely overlap. Then, the reverse rotation is stopped and a stop time is set. The speed of the feeding shaft is set according to the required feeding speed and driven in the opposite direction by the drive device so that the spiral feeding shaft feeds the mixed material into the extruder. The end position of each feeding is set at the position where the two layers of circular dropping holes are completely misaligned. Second scheme: After mixing, the drive device rotates directly in the opposite direction and the speed of the feeding shaft is set according to the required feeding speed. The spiral feeding shaft is driven in the opposite direction by the drive device so that the mixed material is fed into the extruder. The end position of each feeding is set at the position where the two layers of circular dropping holes are completely misaligned. S4, Extrusion: The material is melted and extruded through an extruder, then cooled and shaped into sheets; S5, Crushing: The sheet material cooled and formed in S4 is coarsely crushed, finely crushed, ground, and sieved to obtain the finished product; In step S3, the angle is determined by a Hall sensor.

10. The method for preparing polyester powder coating according to claim 9, characterized in that, The gap between the circular drop holes on the annular top plate and the annular bottom plate is wider than the diameter of the circular drop holes to provide redundant space at the end of the material feeding position.

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