A polyphenylene sulfide anticorrosive coating spraying device and a coating preparation process thereof

Abstract

The application provides a polyphenylene sulfide anticorrosion coating spraying device and a coating preparation process thereof, and relates to the field of polyphenylene sulfide (PPS) anticorrosion coating spraying technology. In view of the problems of the existing PPS spraying device, such as the clamping to generate a spraying dead angle, the need for frequent manual turning for multi-surface spraying, the lack of a high-temperature-resistant automatic clamping mechanism, the separation of the preheating, spraying and curing processes leading to low efficiency, and the difficulty in guaranteeing the consistency of the coating quality, the application clamps the workpiece from a first direction through two clamping pipes, realizes six full coverings through twice clamping by the lifting and rotation conversion of the bracket plate, realizes the rotation driving in a high-temperature environment through the spline sleeve in the clamping pipe and the synchronous belt transmission, and completes the preheating and overall final curing through the infrared heating assembly. The application realizes the full-automatic and dead-angle-free spraying of the PPS anticorrosion coating, and improves the production efficiency and the consistency of the coating quality.

Description

Technical Field

[0001] This invention relates to the field of polyphenylene sulfide (PPS) anti-corrosion coating spraying technology, specifically to a polyphenylene sulfide anti-corrosion coating spraying device and its coating preparation process. Background Technology

[0002] Polyphenylene sulfide (PPS) is a novel high-performance thermoplastic resin with advantages such as high mechanical strength, high temperature resistance, chemical resistance, good thermal stability, and excellent electrical properties. Its anti-corrosion coatings are widely used in electronics, automotive, machinery, and chemical industries. Currently, the main spraying methods for PPS anti-corrosion coatings include suspension spraying, flame spraying, and electrostatic powder spraying. Among these, flame spraying is more widely used due to its relatively simple equipment and ease of on-site application.

[0003] The existing PPS anti-corrosion coating spraying equipment and processes have the following shortcomings: Clamping creates blind spots in the spraying process, affecting coating integrity. Existing spraying equipment often obstructs the spraying of workpieces during fixation, making it difficult to reach the clamped areas. While some solutions alleviate this by placing sponge pads inside the clamping plates, allowing PPS spraying material to flow from the gaps in the pads into the workpiece's outer surface, these pads are prone to clogging and are only suitable for simple-shaped workpieces. For solid workpieces without internal cavities or shielding surfaces, the problem of clamping blind spots remains significant.

[0004] Multi-faceted spraying requires frequent flipping, resulting in low automation. Existing equipment requires multiple manual flipping or transfers of multi-faceted workpieces for full-surface spraying, a cumbersome process. Furthermore, the already sprayed coating is susceptible to contamination or heat loss during flipping, affecting coating quality. While some equipment achieves a degree of flipping through rotating structures, it lacks precise angle control and positioning capabilities, making it difficult to meet the process requirements for high-quality coatings.

[0005] There is a lack of automated clamping and transmission mechanisms adapted to the high-temperature PPS process. PPS flame spraying requires the workpiece surface to be preheated to 300-350°C, and the spraying and curing processes also need to maintain a high-temperature environment. The clamping components (such as rubber parts and plastic parts) and transmission mechanisms (such as conventional belt drives) of existing spraying equipment cannot withstand this temperature for a long time, which limits the realization of fully automated spraying.

[0006] The separation of preheating, spraying, and curing processes leads to low efficiency. In existing processes, the preheating, spraying, and curing of workpieces are usually completed in separate steps in an open environment or in different equipment. Frequent workpiece transfers result in significant heat loss, increased energy consumption, and a longer overall process cycle. The total time for traditional PPS spraying processes is typically 4 to 6 hours.

[0007] Coating quality consistency is difficult to guarantee. Existing processes are highly dependent on operator experience, and the control of coating thickness and uniformity is unstable, making it difficult to achieve standardized production.

[0008] To address the aforementioned issues, this invention provides a polyphenylene sulfide (PPS) anti-corrosion coating spraying device and its coating preparation process. The aim is to achieve automated, full-surface spraying of workpieces without dead angles through an integrated sealed box structure design and a matching coating preparation process, thereby improving coating quality and production efficiency. Summary of the Invention

[0009] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a polyphenylene sulfide (PPS) anti-corrosion coating spraying device and its coating preparation process, which solves the problems existing in the PPS anti-corrosion coating spraying device and its coating preparation process, such as spraying dead corners caused by clamping obstruction, low efficiency due to frequent manual flipping for multi-sided spraying, easy contamination of coatings, lack of high-temperature resistant automated clamping mechanism, heat loss and increased energy consumption due to separation of preheating, spraying and curing processes, and difficulty in ensuring coating quality consistency.

[0010] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: Technical solutions to the problem of blind spots in spraying caused by clamping To address the problem in existing spraying devices where the clamping area is obstructed and difficult to spray when holding a workpiece, especially for solid workpieces without internal cavities or shielding surfaces, this invention provides a two-stage clamping and reversing structure. Two clamping tubes are arranged front-to-back within a sealed housing. The ends of the two clamping tubes extend from the left and right side walls of the sealed housing and can move relative to each other in the front-to-back direction. A clamping plate is located on the opposite side of the two clamping tubes for contacting the workpiece. A support plate is located at the bottom of the sealed housing to support the workpiece, and the support plate can be raised, lowered, and rotated relative to the sealed housing. During clamping, the support plate rises to deliver the workpiece between the two clamping tubes. The two clamping tubes then move relative to each other in the front-to-back direction and clamp the workpiece from the first direction via the clamping plate. The support plate then descends to its original position. When a reversal is needed, the bracket plate rises to support the workpiece, and the two clamping tubes move in opposite directions to release the workpiece. After the bracket plate rotates 90 degrees, the two clamping tubes move relative to each other again and clamp the workpiece from a second direction, which is perpendicular to the first direction. The bracket plate then descends to its original position. Through these two clamping reversals, the surfaces of the workpiece that were originally covered by the clamping plates are exposed below the spray gun after the reversal, thus achieving full-surface spraying without blind spots.

[0011] Technical solutions to the problem of frequent manual flipping during multi-sided spraying To address the problems of existing devices requiring multiple manual flipping or transfers of workpieces for full-surface spraying of multifaceted workpieces, which are cumbersome and prone to contamination or heat loss during flipping, this invention integrates the clamping, rotation, and reversing of the clamping tubes within a sealed housing. The forward and backward movement of the two clamping tubes is driven by first cylinders located within the side chambers on both sides of the sealed housing. First guide rods for guiding the forward and backward movement of the clamping tubes are fixedly connected to the inner walls of the side chambers. The clamping tubes are hollow tubular structures. One end of the clamping tube extending into the side chamber is rotatably connected to a splined sleeve. A driven shaft is rotatably connected to the section of the clamping tube inside the sealed housing, with one end of the driven shaft fixedly connected to a clamping plate. A first synchronous pulley is fixedly connected to the section of the splined sleeve inside the clamping tube, and a second synchronous pulley is fixedly connected to the section of the driven shaft inside the clamping tube. A metal chain drive belt is fitted between the first and second synchronous pulleys. One of the side chambers houses a drive shaft. One end of the drive shaft is rotatably connected to the inner wall of the side chamber, while the other end is connected to a first servo motor and a reducer to drive its rotation. A splined shaft is positioned on the outer periphery of the drive shaft corresponding to each splined sleeve. The splined shaft and splined sleeve are slidably connected and can transmit torque. The first servo motor drives the drive shaft to rotate, transmitting torque to the first synchronous pulley via the sliding engagement of the splined shaft and splined sleeve. This torque, in turn, drives the second synchronous pulley and driven shaft to rotate via a metal chain drive belt, thereby driving the clamping plate to rotate the workpiece and sequentially exposing each surface to be sprayed to the spray gun. The entire clamping, rotation, and reversing process is completed automatically within the sealed chamber, requiring no manual intervention.

[0012] Technical solutions to the problem of lack of high-temperature resistant automated clamping mechanisms To address the issue that PPS spraying requires temperatures exceeding 300 degrees Celsius, and existing clamping and transmission mechanisms struggle to withstand such temperatures long-term, this invention incorporates a high-temperature resistant design for the clamping and transmission mechanisms. Side chambers are located on the left and right sides of the sealed housing. The two ends of the clamping tube extend into the corresponding side chambers, and the side chambers are connected to the sealed housing via sliding holes through which the clamping tube passes. Sliding holes are provided on the left and right side walls of the sealed housing for each clamping tube to pass through. A cover plate is located on the outer periphery of the clamping tube near the sliding hole, designed to cover the sliding hole as the clamping tube moves. When the clamping tube moves to any position, the cover plate covers the corresponding sliding hole, effectively preventing heat transfer from the sealed housing to the side chambers. The clamping tube is a hollow tubular structure, with a spline sleeve, metal chain drive belt, and synchronous pulley housed inside, isolating it from the high-temperature area of ​​the sealed housing. A front door with a viewing window is rotatably connected to the front wall of the sealed housing, allowing operators to observe the spraying process inside the housing.

[0013] Technical solutions to address the inefficiency caused by the separation of preheating, spraying, and curing processes. To address the problem that in existing processes, preheating, spraying, and curing of workpieces are typically performed in separate steps in open environments or different equipment, leading to significant heat loss, increased energy consumption, and extended overall process cycles due to frequent workpiece transfers, this invention integrates preheating, spraying, and curing within a single sealed enclosure. Infrared heating components are installed on both the left and right side walls of the sealed enclosure. These components are mounted on mounting bases, which are fixedly connected to one end of a heat-insulating rod. The other end of the heat-insulating rod is fixedly connected to the extension shaft of a second cylinder, which is located on the lower inner wall of the side enclosure. The second cylinder drives the infrared heating components to extend and retract within the sealed enclosure. When preheating or curing is required, the second cylinder extends the infrared heating components toward the workpiece to a predetermined heating position close to the workpiece surface. When spraying is required, the infrared heating components retract to the inner wall of the sealed enclosure to avoid the spraying operation. Before spraying, the infrared heating element preheats each surface of the workpiece to be sprayed to 300 to 350 degrees Celsius. After spraying, the infrared heating element heats the inside of the sealed chamber to 320 to 340 degrees Celsius and maintains this temperature for 15 to 60 minutes, allowing the coating to cure completely. The entire preheating, spraying, and curing process is completed inside the sealed chamber, eliminating the need to transfer the workpiece between different devices.

[0014] Technical solutions to the problem of difficulty in ensuring coating quality consistency To address the problems of existing processes that rely heavily on operator experience, have unstable coating thickness and uniformity control, and are difficult to standardize, this invention achieves consistent coating quality by automating and standardizing the entire process of preheating, spraying, and curing. A top chamber is located at the top of the sealed housing, inside which is a spray gun drive device. The spray gun is positioned below the drive device and extends into the sealed housing. The drive device controls the spray gun's movement along the X, Y, and Z axes, enabling precise scanning spraying of all workpiece surfaces. A pressure sensor is installed between the extended shaft of the first cylinder and the outer wall of the clamping tube to detect the clamping force and feed it back to the control system, ensuring consistent clamping force each time and preventing workpiece displacement or deformation due to fluctuations in clamping force. During the preheating stage, infrared heating components uniformly preheat all surfaces of the workpiece, providing a stable bonding foundation between the coating and the substrate. After spraying, the entire coating is finally cured by an infrared heating element. This causes the PPS material at the seams of the coatings created by the multiple spraying processes to remelt, and the molecular chains to diffuse and intertwine, achieving self-healing of the seams and resulting in a seamless, high-bonding-strength overall anti-corrosion coating. Throughout the process, clamping, rotation, reversing, preheating, spraying, and curing are all automatically executed by the control system according to a preset program, reducing the impact of human intervention on coating quality.

[0015] (III) Beneficial Effects This invention provides a polyphenylene sulfide (PPS) anti-corrosion coating spraying device and its coating preparation process. It has the following beneficial effects: 1. Compared with the existing technology, the polyphenylene sulfide anti-corrosion coating spraying device and its coating preparation process use two clamping tubes to clamp the workpiece from the first direction. With the help of the bracket plate, the workpiece is rotated 90 degrees in the clamping tube state and then clamped again, so that the workpiece can complete the full surface coverage of six sides in the two clamping. The surface that the clamping plate has contacted is exposed under the spray gun for spraying after the direction is reversed. This solves the problem of spraying dead angles caused by clamping and blocking of solid workpieces without internal cavity and shielding surface.

[0016] 2. Compared with existing technologies, this polyphenylene sulfide anti-corrosion coating spraying device and its coating preparation process achieve fully automated operation of workpiece clamping, rotation, and reversal by sliding the spline sleeve inside the clamping tube with the spline shaft on the drive shaft. This allows the clamping tube to move in the front-back direction to clamp or release the workpiece while the rotational torque of the drive shaft is transmitted to the clamping plate through a metal chain transmission belt, driving the workpiece to rotate. Combined with the lifting and rotation reversing of the bracket plate, this achieves fully automated operation of workpiece clamping, rotation, and reversing, eliminating the need for manual flipping and solving the problems of low efficiency and easy contamination of the coating caused by frequent manual flipping during multi-sided spraying.

[0017] 3. Compared with the existing technology, the polyphenylene sulfide anti-corrosion coating spraying device and its coating preparation process, by setting the clamping tube as a hollow tubular structure and setting the transmission components such as spline sleeve, metal chain transmission belt, and driven shaft inside the clamping tube, and with the cover plate on the outer peripheral wall of the clamping tube that covers the sliding hole as the clamping tube moves, as well as the heat insulation rod and the guide rod set on the inner wall of the side box, isolates the transmission components and drive components that are not resistant to high temperature from the high temperature area of ​​the sealed box, thus solving the problem that the existing clamping and transmission mechanisms cannot withstand high temperature environments above 300℃ for a long time.

[0018] 4. Compared with existing technologies, this polyphenylene sulfide anti-corrosion coating spraying device and its coating preparation process integrate preheating, spraying and curing into the same cavity through a sealed box. The workpiece remains inside the sealed box during clamping, rotation and reversal, eliminating the need for transfer between different devices. In conjunction with an infrared heating component to preheat and cure the workpiece, heat loss is reduced, the overall process cycle is shortened, and the problem of low efficiency caused by the separation of preheating, spraying and curing processes is solved.

[0019] 5. Compared with existing technologies, this polyphenylene sulfide anti-corrosion coating spraying device and its coating preparation process preheat the workpiece on all sides and cure it after spraying through infrared heating components. Combined with the secondary clamping after the bracket plate rotates and the spray gun moving and spraying on the upper part of the sealed box, the entire preheating, spraying and curing process is completed automatically by the device, reducing the uncertainty caused by manual intervention. Furthermore, the coating seams are self-healed through the overall final curing, which solves the problems of high dependence on operator experience and difficulty in ensuring the consistency of coating quality in existing processes. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 for Figure 1 Enlarged view of a portion of point A in the middle; Figure 3 This is a partial half-section diagram of the side box; Figure 4 for Figure 3 Enlarged view of a section at point B in the middle; Figure 5 This is a partial sectional view of the internal structure of the sealed box from the top. Figure 6 for Figure 5 Enlarged view of a section at point C; Figure 7 This is a partial top sectional view of the connection between the clamping tube and the spline sleeve; Figure 8 This is a partial sectional view of the top surface at the connection between the clamping tube and the driven shaft; Figure 9 This is a partial sectional view of the connection structure between the clamping tube and the first cylinder; Figure 10 A schematic diagram of the second cylinder, mounting base, and infrared heating element; Figure 11 This is a partial sectional view of the connection between the bracket plate and the vertical shaft.

[0021] Among them, 1: base box; 2: sealed box; 201: front door; 202: viewing window; 203: sliding hole; 3: top box; 4: side box; 5: first cylinder; 6: reducer; 7: first servo motor; 8: clamping tube; 801: cover plate; 9: first guide rod; 10: second cylinder; 1001: heat insulation rod; 11: rotating seat; 12: drive shaft; 13: splined shaft; 14: splined sleeve; 15: mounting seat; 16: infrared heating component; 17: second guide rod; 18: driven shaft; 19: clamping plate; 20: bracket plate; 21: first synchronous pulley; 22: metal chain drive belt; 23: second synchronous pulley; 24: pressure sensor; 25: vertical shaft; 26: lifting plate; 27: third guide rod; 28: second servo motor; 29: support frame; 30: third cylinder. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example: like Figures 1 to 11As shown, this invention provides a polyphenylene sulfide (PPS) anti-corrosion coating spraying device, including a sealed housing 2. The sealed housing 2 is a closed cavity used to provide an integrated working environment for preheating, spraying, and curing. The walls of the sealed housing 2 are made of stainless steel, and the inner wall is coated with a high-temperature resistant, non-stick coating to prevent PPS powder from adhering to the inner wall of the housing. A bottom chamber 1 is fixedly connected to the lower wall of the sealed housing 2, a top chamber 3 is fixedly connected to the upper wall of the sealed housing 2, and side chambers 4 are fixedly connected to the left and right side walls of the sealed housing 2, respectively. The sealed housing 2, bottom chamber 1, top chamber 3, and side chambers 4 are all made of 304 stainless steel to adapt to high-temperature working environments above 300°C. A front door 201 is hinged to the front wall of the sealed housing 2, and a viewing window 202 is embedded in the front door 201. The viewing window 202 is made of high-temperature resistant quartz glass, allowing the operator to easily observe the spraying status inside the housing. A high-temperature resistant sealing strip is provided between the front door 201 and the sealed box 2. The high-temperature resistant sealing strip is made of perfluoroether rubber with a temperature resistance of not less than 340℃ to ensure the airtightness of the sealed box 2 under heating conditions.

[0024] The top housing 3 houses a spray gun drive unit, which includes X-axis, Y-axis, and Z-axis linear modules, each driven by a servo motor. The spray gun is fixedly connected to the lower end of the spray gun drive unit and extends into the sealed housing 2. The spray gun drive unit controls the movement of the spray gun along the X, Y, and Z axes, enabling scanning spraying of the workpiece surfaces. The spray gun has an internal water-cooled circulating cooling structure, including cooling water channels within the spray gun body. These channels extend axially along the spray gun and surround the powder delivery channel. The spray gun has a cooling water inlet and outlet. Cooling water enters the cooling water channels through the inlet, flows past the front end of the spray gun, and exits through the outlet via the return channel, forming a circulating cooling loop to ensure continuous and stable operation of the spray gun in high-temperature environments above 300°C. The spray gun body is made of high-temperature resistant stainless steel, and the nozzle is made of ceramic.

[0025] The sealed housing 2 contains two clamping tubes 8 arranged front to back. Each clamping tube 8 is a square, hollow tubular structure made of high-temperature resistant stainless steel. The two ends of each clamping tube 8 extend from the left and right side walls of the sealed housing 2 and into the corresponding side chambers 4. Sliding holes 203 are provided on the left and right side walls of the sealed housing 2 for each clamping tube 8 to pass through. The opening size of the sliding hole 203 on the side wall of the sealed housing 2 is larger than the cross-sectional size of the clamping tube 8, allowing the clamping tube 8 to move freely in the front-back direction within the sliding hole 203. A cover plate 801 is fixedly connected to the outer peripheral wall of the clamping tube 8 near the sliding hole 203. The width of the cover plate 801 is greater than the width of the sliding hole 203. When the clamping tube 8 moves to any position, the cover plate 801 can cover the corresponding sliding hole 203. A high-temperature resistant sealing gasket is fixed on the side of the cover plate 801 facing the side wall of the sealed box 2. The sealing gasket is made of ceramic fiber material. The cover plate 801 and the side wall of the sealed box 2 form a sliding sealing fit through the sealing gasket, which plays the role of isolating the heat inside the sealed box 2 from the side box 4.

[0026] Four sets of first cylinders 5 are installed on the front and rear walls of the side box 4. Each first cylinder 5 is a high-temperature resistant cylinder, and its piston rod and internal seals are made of perfluoroelastomer rubber. The extension shaft of the first cylinder 5 passes through the side wall of the side box 4 and extends into the interior of the side box 4. A pressure sensor 24 is installed between the end of the extension shaft of the first cylinder 5 and the outer wall of the clamping tube 8. The pressure sensor 24 is a high-temperature type pressure sensor, and its sensitive element is fixedly connected to the outer wall of the clamping tube 8 to detect the clamping force and feed the signal back to the control system. A first guide rod 9 is fixedly connected to the inner wall of the side box 4, on the side of the first cylinder 5 away from the sealed box 2. The first guide rod 9 is a cylindrical guide rod made of high-temperature resistant stainless steel, and its surface is polished to reduce sliding friction. The axis of the first guide rod 9 is parallel to the axis of the first cylinder 5. The first guide rod 9 passes through the two clamping tubes 8 and is slidably connected to them. A high-temperature resistant sliding bearing is embedded in the through hole on the clamping tube 8 that mates with the first guide rod 9. The bearing is made of copper-based graphite self-lubricating material. The four sets of first cylinders 5 are driven by the same air source and move synchronously, causing the two clamping tubes 8 to move relative to each other or in opposite directions along the guiding direction of the first guide rod 9, i.e., in the front-back direction, so as to clamp or release the workpiece.

[0027] A reducer 6 is fixedly connected to the front wall of the side chamber 4 located on the right side of the sealed housing 2. The reducer 6 is a planetary gear reducer, with its internal gears and housing made of high-temperature resistant materials, and its lubricating oil being high-temperature resistant synthetic grease. A first servo motor 7 is fixedly connected to the input end of the reducer 6. The first servo motor 7 is a servo motor with an absolute encoder, which is used to detect the rotation angle of the motor in real time and feed it back to the control system. The output end of the reducer 6 passes through the front wall of the side chamber 4 and extends into the interior of the side chamber 4. The inner side wall of the side chamber 4 away from the sealed housing 2 is rotatably connected to the drive shaft 12 via a rotating seat 11. The rotating seat 11 includes a bearing seat fixed to the inner side wall of the side chamber 4 and a high-temperature rolling bearing disposed in the bearing seat, the bearing being a ceramic ball bearing. The front end of the drive shaft 12 is fixedly connected to the end of the reducer 6 that extends into the interior of the side chamber 4. The inner walls of the two clamping tubes 8 near the right end are rotatably connected to spline sleeves 14 via high-temperature rolling bearings. The drive shaft 12 passes through two splined sleeves 14, and a splined shaft 13 is provided on the outer peripheral wall of the drive shaft 12 corresponding to each splined sleeve 14. The splined shaft 13 and the drive shaft 12 are integrally formed or fixed by a key connection. The splined shaft 13 and the splined sleeve 14 are slidably connected and can transmit torque, that is, the splined sleeve 14 can slide freely along the axial direction of the splined shaft 13, and the rotational torque of the drive shaft 12 can be transmitted to the splined sleeve 14 through the cooperation of the splined shaft 13 and the splined sleeve 14. When the clamping tube 8 moves in the back-and-forth direction, the splined sleeve 14 slides along the splined shaft 13 with the clamping tube 8, while maintaining the torque transmission capability.

[0028] Two clamping tubes 8 are located within the sealed housing 2, at the center of their length, and each is rotatably connected to a driven shaft 18 via a high-temperature rolling bearing. The driven shafts 18 on the two clamping tubes 8 are arranged in a front-to-back configuration. Clamping plates 19 are fixedly connected to the opposite ends of the two sets of driven shafts 18, and the two sets of clamping plates 19 are used to contact the clamped workpiece. The clamping plates 19 are made of high-temperature resistant stainless steel, and their workpiece-facing surface has anti-slip textures to increase friction with the workpiece and prevent damage to the workpiece surface. A spline sleeve 14 is fixedly connected to a first synchronous pulley 21 within the clamping tube 8. A second synchronous pulley 23 is fixedly connected to a section of the driven shaft 18 within the clamping tube 8. A metal chain drive belt 22 is fitted between the left-to-right opposite first synchronous pulley 21 and second synchronous pulley 23. The metal chain drive belt 22 is made of stainless steel chain, and its long-term operating temperature can withstand temperatures above 300℃.

[0029] The power output from the first servo motor 7 is reduced by the reducer 6 and drives the drive shaft 12 to rotate. The drive shaft 12 transmits torque to the first synchronous pulley 21 through the sliding fit between the spline shaft 13 and the spline sleeve 14. The first synchronous pulley 21 drives the second synchronous pulley 23 to rotate through the metal chain transmission belt 22, which in turn drives the driven shaft 18 and the clamping plate 19 to rotate, causing the clamped workpiece to flip and expose each surface to be sprayed to the bottom of the spray gun in sequence.

[0030] A bracket plate 20 is provided at the bottom of the sealed housing 2. The bracket plate 20 is made of high-temperature resistant stainless steel, and its upper surface is flat, used to support the workpiece. A third cylinder 30 is fixedly connected to the lower inner wall of the bottom housing 1. The axis of the third cylinder 30 is perpendicular to the horizontal plane. The third cylinder 30 is the same high-temperature resistant cylinder as the first cylinder 5. A support frame 29 is connected to the end of the extended shaft of the third cylinder 30. The support frame 29 is a metal frame structure made of stainless steel. A lifting plate 26 is fixedly connected to the upper end of the support frame 29. The lifting plate 26 is a horizontally set metal plate made of stainless steel. A second servo motor 28 is fixedly connected to the lower wall of the lifting plate 26 and located inside the cavity of the support frame 29. The output shaft of the second servo motor 28 passes through the lifting plate 26 and extends to the upper side of the lifting plate 26. A vertical shaft 25 is fixedly connected to the end of the output shaft of the second servo motor 28 that extends above the lifting plate 26. The upper end of the vertical shaft 25 penetrates the lower wall of the sealed housing 2 and extends into the interior of the sealed housing 2. A bracket plate 20 is fixedly connected to the end of the vertical shaft 25 that extends into the sealed housing 2. A high-temperature resistant sealing structure, including ceramic fiber packing, is provided between the vertical shaft 25 and the lower wall of the sealed housing 2 to prevent heat leakage from the interior of the sealed housing 2 through the penetration point of the vertical shaft 25. Multiple sets of third guide rods 27 are provided on the inner lower wall of the bottom box 1. The third guide rods 27 are cylindrical guide rods made of high-temperature resistant stainless steel. The upper ends of all sets of third guide rods 27 penetrate the lifting plate 26 and are slidably connected to it. High-temperature resistant sliding bearings are embedded in the through holes on the lifting plate 26 that mate with the third guide rods 27. The second servo motor 28 is a servo motor with an absolute encoder. The absolute encoder is used to detect the rotation angle of the bracket plate 20 in real time and feed it back to the control system, realizing closed-loop control of the rotation angle of the bracket plate 20 without the need for a separate angle sensor.

[0031] A second cylinder 10 is fixedly connected to the lower inner wall of each of the side chambers 4 on both sides of the sealed housing 2. The second cylinder 10 is a high-temperature resistant cylinder, the same as the first cylinder 5. The horizontal height of the second cylinder 10 is lower than that of the clamping tube 8 to avoid the position of the sliding hole 203. A heat insulation rod 1001 is fixedly connected to the end of the extended shaft of the second cylinder 10. The heat insulation rod 1001 is made of ceramic rod to reduce the conduction of heat inside the sealed housing 2 to the second cylinder 10 along the heat insulation rod 1001. The end of the heat insulation rod 1001 away from the second cylinder 10 passes through the side wall of the sealed housing 2 and extends into the interior of the sealed housing 2. A high-temperature resistant sealing sleeve is provided between the heat insulation rod 1001 and the side wall of the sealed housing 2. A mounting base 15 is fixedly connected to the end of the heat insulation rod 1001 that extends into the interior of the sealed housing 2. The mounting base 15 is made of high-temperature resistant stainless steel. An infrared heating element 16 is provided on the side of the mounting base 15 facing the center of the sealed housing 2. The infrared heating element 16 includes multiple infrared radiation heating tubes. These tubes use quartz glass shells and contain built-in nickel-chromium alloy resistance wires, with their radiation wavelength matching the absorption wavelength of the PPS material. The infrared heating element 16 is used to preheat the workpiece surface and bake the coating. A second guide rod 17 is provided at each of the four corners of the side where the mounting base 15 connects to the heat insulation rod 1001. The second guide rod 17 is a cylindrical guide rod made of high-temperature resistant stainless steel. The end of the second guide rod 17 furthest from the mounting base 15 penetrates the side wall of the sealed housing 2 and is slidably connected thereto. The minimum distance between the two clamping tubes 8 is greater than the width of the mounting base 15 in the front-to-back direction, ensuring that the mounting base 15 does not interfere with the clamping tubes 8 when it extends into the sealed housing 2. Driven by the second cylinder 10, the infrared heating element 16 extends and retracts within the sealed housing 2, extending towards the workpiece to a predetermined heating position close to the workpiece surface, or retracting to the inner side wall of the sealed housing 2 to avoid spraying operations.

[0032] A non-contact temperature sensor is also installed inside the sealed housing 2. The temperature sensor is an infrared thermometer, installed on the top inner wall of the sealed housing 2, with its probe facing the workpiece area. It is used to monitor the workpiece surface temperature in real time and feed the signal back to the control system. The control system uses a programmable logic controller (PLC). Its signal input terminals are electrically connected to the pressure sensor 24, the non-contact temperature sensor, the absolute encoder of the first servo motor 7, and the absolute encoder of the second servo motor 28, respectively. Its signal output terminals are electrically connected to the control valves of the first cylinder 5, the second cylinder 10, and the third cylinder 30, the first servo motor 7, the second servo motor 28, the spray gun drive device, and the powder supply device of the spray gun, respectively. The control system is used to control the timing and operating parameters of each component according to a preset program and the feedback signals from each sensor.

[0033] The following describes in detail the polyphenylene sulfide anti-corrosion coating preparation process provided by the present invention, in conjunction with the aforementioned apparatus. This process is designed for solid workpieces that require full-surface spraying on all six sides, and these workpieces are polyhedral structures without internal cavities or shielding surfaces.

[0034] S1: Workpiece placement and initial clamping.

[0035] The operator opens the front door 201, places the workpiece to be sprayed in the center of the upper surface of the bracket plate 20, and closes the front door 201. The control system activates the third cylinder 30, whose extension shaft extends upward, pushing the lifting plate 26 upward through the support frame 29. The lifting plate 26 drives the vertical shaft 25 and the bracket plate 20 to rise synchronously, sending the workpiece upward between the two clamping tubes 8. When the workpiece reaches the clamping height, the control system activates four sets of first cylinders 5, which operate synchronously, extending their extension shafts and pushing the two clamping tubes 8 to move relative to each other along the guide direction of the first guide rod 9, i.e., the front-back direction. The clamping plate 19 on the opposite side of the two clamping tubes 8 gradually approaches and contacts the opposite sides of the workpiece; this direction is the first direction (front-back direction). As the first cylinders 5 continue to extend, the clamping plate 19 applies clamping force to the workpiece. The pressure sensor 24, located between the end of the extension shaft of the first cylinder 5 and the outer wall of the clamping tube 8, detects the clamping force in real time and feeds the signal back to the control system. When the clamping force reaches the preset clamping force threshold in the control system, the control system determines that the clamping is in place, stops the action of the first cylinder 5, and maintains the current pressure. Subsequently, the control system starts the reverse action of the third cylinder 30. The extension shaft of the third cylinder 30 retracts, driving the bracket plate 20 to descend and reset to the bottom of the sealed box 2. The workpiece is held in a suspended state between the two clamping tubes 8 by the clamping plate 19. At this time, the workpiece is no longer in contact with the bracket plate 20.

[0036] S2: Full warm-up.

[0037] The control system activates the second cylinders 10 on both sides. The extension shafts of the second cylinders 10 extend and push the mounting base 15 and the infrared heating element 16 mounted on the mounting base 15 through the heat insulation rod 1001. This causes the infrared heating element 16 to extend from the inner wall of the sealed housing 2 towards the workpiece until it reaches the predetermined heating position close to the left and right sides of the workpiece. The control system activates the infrared heating element 16 to radiate heat to the left and right sides of the workpiece. Simultaneously, a non-contact temperature sensor monitors the surface temperature of the left and right sides of the workpiece in real time and feeds the signal back to the control system. When the surface temperature of the left and right sides of the workpiece reaches the preset preheating temperature, the control system activates the first servo motor 7. The power output from the first servo motor 7 is reduced by the reducer 6 and drives the drive shaft 12 to rotate. The drive shaft 12 transmits torque to the first synchronous pulley 21 through the sliding engagement of the spline shaft 13 and the spline sleeve 14. The first synchronous pulley 21 drives the second synchronous pulley 23 to rotate through the metal chain transmission belt 22, which in turn drives the driven shaft 18 and the clamping plate 19 to rotate. Since the workpiece is clamped by the clamping plate 19, the rotation of the clamping plate 19 causes the workpiece to rotate 90° synchronously around the axis of the driven shaft 18. After rotation, the original upper and lower sides of the workpiece are rotated to the left and right sides, exposed to the heating area of ​​the infrared heating element 16. The infrared heating element 16 continues to radiate heat to the upper and lower sides of the workpiece until the two sides reach the preset preheating temperature. The preheating temperature is set to 300℃ to 350℃. After preheating, the control system can control the second cylinder 10 to drive the infrared heating element 16 to retract to the inner wall of the sealed box 2 to avoid the spraying operation, or to keep the infrared heating element 16 inside the sealed box 2 to keep the workpiece warm.

[0038] S3: Initial coating.

[0039] The control system activates the spray gun drive, which moves the spray gun along the X, Y, and Z axes to the predetermined spraying start position. The control system also activates the powder supply device to supply PPS powder to the spray gun and simultaneously starts spraying. The first servo motor 7 drives the workpiece to rotate sequentially according to the control system's instructions, exposing each surface to be sprayed to the spray gun in turn. The spray gun drive controls the spray gun's movement according to the preset spraying path, performing a scanning spray on each surface. During spraying, the sealed housing 2 remains airtight to prevent PPS powder from escaping and contaminating the environment, while maintaining the internal temperature of the housing at no less than the melting temperature of the PPS powder (approximately 285°C) to ensure that the PPS powder sprayed onto the workpiece surface melts and spreads promptly. After spraying is complete, the control system shuts off the powder supply device and the spray gun.

[0040] S4: Reversal and secondary clamping.

[0041] After the workpiece has been coated on all four sides (front, back, left, and right) in its initial clamping state, it needs to be reversed to expose the remaining two sides (top and bottom). The control system activates the third cylinder 30, whose extension shaft extends upwards, pushing the bracket plate 20 upwards via the support frame 29, lifting plate 26, and vertical shaft 25 until the upper surface of the bracket plate 20 contacts and supports the lower surface of the workpiece. At this point, the bracket plate 20 bears the entire weight of the workpiece. The control system then activates the four sets of first cylinders 5 to reverse their actions, causing the extension shafts of the four sets of first cylinders 5 to retract synchronously, driving the two clamping tubes 8 to move in opposite directions along the front-back direction, and the clamping plate 19 releases the workpiece. The control system then activates the second servo motor 28, whose output shaft rotates, driving the bracket plate 20 and the workpiece supported on the bracket plate 20 to rotate 90° together via the vertical shaft 25. The absolute encoder of the second servo motor 28 detects the rotation angle in real time and feeds it back to the control system. When the rotation angle reaches 90°, the control system stops the second servo motor 28. At this point, the original top and bottom surfaces of the workpiece are rotated to the front-back direction, i.e., the direction opposite to the clamping plate 19. The control system restarts the four sets of first cylinders 5, which operate synchronously, extending their shafts and pushing the two clamping tubes 8 to move relative to each other in the front-back direction. The clamping plate 19 clamps the opposite sides (i.e., the original top and bottom surfaces) of the workpiece from the second direction (which is perpendicular to the first direction). The pressure sensor 24 detects the clamping force and feeds it back to the control system. After confirming that the clamping force meets the standard, the control system starts the third cylinder 30 to reverse the action, driving the bracket plate 20 to descend and reset. The workpiece remains suspended under the clamping of the clamping plate 19.

[0042] S5: Preheating and spraying of the remaining surface.

[0043] After the reversal is completed, the top and bottom surfaces of the workpiece, which were previously covered by the clamping plate 19, are now exposed on the left and right sides. The control system activates the second cylinders 10 on both sides, driving the infrared heating components 16 to extend from the inner wall of the sealed housing 2 toward the workpiece, preheating the remaining uncoated surfaces of the workpiece at a temperature set to 300°C to 350°C. After preheating, the remaining uncoated surfaces of the workpiece are sequentially coated using the spray gun drive device and the first servo motor 7.

[0044] S6: Final curing of the entire structure.

[0045] After all surfaces are coated, the control system activates the second cylinders 10 on both sides, driving the infrared heating element 16 to extend from the inner wall of the sealed chamber 2 towards the workpiece to the predetermined heating position. The control system activates the infrared heating element 16 to heat the interior of the sealed chamber 2 to the curing temperature of polyphenylene sulfide. The curing temperature is set to 320℃ to 340℃. A non-contact temperature sensor monitors the temperature inside the sealed chamber 2 in real time and feeds it back to the control system. The control system adjusts the heating power of the infrared heating element 16 to maintain the temperature inside the sealed chamber 2 within the curing temperature range and maintains the temperature. The holding time is set to 15 to 60 minutes, with the specific holding time determined according to the coating thickness; the thicker the coating, the longer the holding time. During the holding process, the sprayed PPS coating fully melts and flows, and the PPS molecular chains gain sufficient kinetic energy to undergo cross-linking and curing reactions. Simultaneously, in the coating seam areas generated during the multi-coating process, the PPS material melts again, and the molecular chains on both sides of the seam diffuse and intertwine, achieving self-healing of the seam and fusing all coating surfaces into a continuous, uniform, integral anti-corrosion coating.

[0046] S7: Cooling and removal.

[0047] After the heat preservation is completed, the control system shuts down the infrared heating element 16 and controls the second cylinder 10 to retract the infrared heating element 16 to the inner wall of the sealed chamber 2. The control system can activate the cooling system installed on the sealed chamber 2 for programmed temperature control cooling, or allow the workpiece to cool naturally inside the sealed chamber 2. During the cooling process, the cooling rate should be controlled to avoid excessive cooling, which could lead to excessive internal stress in the coating and cause cracks. When the internal temperature of the sealed chamber 2 drops to a safe temperature, the operator opens the front door 201 and removes the coated workpiece. At this time, a continuous, seamless, high-bonding-strength polyphenylene sulfide anti-corrosion coating is formed on the surface of the workpiece.

[0048] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the first cylinder 5, the second cylinder 10, and the third cylinder 30 can all be replaced with linear drive elements such as hydraulic cylinders or electric actuators; the first servo motor 7 and the second servo motor 28 can all be replaced with other types of rotary drive elements; the infrared heating element 16 can be replaced with a resistance heating tube or a laser heating device; the metal chain drive belt 22 can be replaced with other high-temperature resistant drive belts / chains, but it must be ensured that its long-term operating temperature meets the requirement of above 300°C. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A polyphenylene sulfide anti-corrosion coating spraying device, comprising a sealed housing (2), a top box (3) disposed on the upper part of the sealed housing (2), a spray gun driving device disposed inside the top box (3), and a spray gun disposed at the lower end of the spray gun driving device, characterized in that, Also includes: A set of clamping tubes (8) for clamping a workpiece from the first direction, the clamping tubes (8) are two tubes and are distributed in front and behind, the two ends of the two clamping tubes (8) extend out of the left and right side walls of the sealing box (2) respectively, and the two clamping tubes (8) can move relative to each other in the front and back direction to clamp or release the workpiece, the first direction being the front and back direction. A clamping plate (19) is disposed on one side opposite to the two clamping tubes (8) and is used to contact the workpiece. A bracket plate (20) is provided at the bottom of the sealed box (2) and is used to support the workpiece. The bracket plate (20) can be raised and lowered relative to the sealed box (2) to send the workpiece between the two clamping tubes (8). The bracket plate (20) can also rotate relative to the sealed box (2). Infrared heating components (16) for heating the workpiece are located on the left and right sides of the sealed box (2) and between the two clamping tubes (8).

2. The polyphenylene sulfide anti-corrosion coating spraying device according to claim 1, characterized in that: The sealing box (2) is provided with side boxes (4) on the left and right sides respectively. The two ends of the clamping tube (8) extend into the side box (4) on the corresponding side respectively. The front wall and rear wall of the side box (4) are each provided with a first cylinder (5) for driving the clamping tube (8) to move in the front and back direction. The left and right side walls of the sealing box (2) are provided with sliding holes (203) for the clamping tube (8) to pass through at each clamping tube (8). The outer peripheral wall of the clamping tube (8) and near the sliding hole (203) are provided with a cover plate (801) for covering the sliding hole (203) as the clamping tube (8) moves.

3. The polyphenylene sulfide anti-corrosion coating spraying device according to claim 2, characterized in that: A pressure sensor (24) for detecting clamping force is provided between the end of the extension shaft of the first cylinder (5) and the outer wall of the clamping tube (8). A first guide rod (9) for guiding the clamping tube (8) to move in the front and back direction is fixedly connected to the inner wall of the side box (4). The first guide rod (9) passes through the two clamping tubes (8) and is slidably connected to the clamping tubes (8).

4. The polyphenylene sulfide anti-corrosion coating spraying device according to claim 1, characterized in that: The clamping tube (8) is a hollow tubular structure. One end of the clamping tube (8) extending into the side box (4) is rotatably connected to a spline sleeve (14). A section of the clamping tube (8) located inside the sealed box (2) is rotatably connected to a driven shaft (18). One end of the driven shaft (18) is fixedly connected to the clamping plate (19). A section of the spline sleeve (14) located inside the clamping tube (8) is fixedly connected to a first synchronous pulley (21). A section of the driven shaft (18) located inside the clamping tube (8) is fixedly connected to a second synchronous pulley (23). A metal chain drive belt (22) is sleeved between the first synchronous pulley (21) and the second synchronous pulley (23).

5. The polyphenylene sulfide anti-corrosion coating spraying device according to claim 4, characterized in that: One of the side boxes (4) is provided with a drive shaft (12). One end of the drive shaft (12) is rotatably connected to the inner wall of the side box (4). The other end of the drive shaft (12) is connected to a first servo motor (7) and a reducer (6) for driving its rotation. The input end of the reducer (6) is fixedly connected to the first servo motor (7). The output end of the reducer (6) is fixedly connected to the drive shaft (12). The outer peripheral wall of the drive shaft (12) is provided with a spline shaft (13) corresponding to each spline sleeve (14). The spline shaft (13) is slidably connected to the spline sleeve (14) and can transmit torque.

6. The polyphenylene sulfide anti-corrosion coating spraying device according to claim 1, characterized in that: A bottom box (1) is provided below the sealed box (2). A third cylinder (30) is provided on the inner lower wall of the bottom box (1). A support frame (29) is connected to the end of the extension shaft of the third cylinder (30). A lifting plate (26) is fixedly connected to the upper end of the support frame (29). A second servo motor (28) is fixedly connected to the lower wall of the lifting plate (26). The output shaft of the second servo motor (28) passes through the lifting plate (26) and is fixedly connected to a vertical shaft (25). The upper end of the vertical shaft (25) passes through the lower wall of the sealed box (2) and is fixedly connected to the bracket plate (20).

7. The polyphenylene sulfide anti-corrosion coating spraying device according to claim 1, characterized in that: A second cylinder (10) is provided on the lower inner wall of the side box (4) on both sides of the sealed box (2). A heat insulation rod (1001) is fixedly connected to the end of the extended shaft of the second cylinder (10). The end of the heat insulation rod (1001) away from the second cylinder (10) passes through the side wall of the sealed box (2) and is fixedly connected to the mounting base (15). The infrared heating component (16) is located on the side of the mounting base (15) facing the center of the sealed box (2). The infrared heating component (16) moves telescopically inside the sealed box (2) under the drive of the second cylinder (10).

8. The polyphenylene sulfide anti-corrosion coating spraying device according to claim 1, characterized in that: The front wall of the sealed box (2) is rotatably connected to a front door (201), and a viewing window (202) is provided on the front door (201); the spray gun is equipped with a water-cooled circulating cooling structure.

9. A process for preparing a polyphenylene sulfide (PPS) anti-corrosion coating, comprising using a PPS anti-corrosion coating spraying apparatus as described in any one of claims 1 to 8, characterized in that, Includes the following steps: S1: Place the workpiece on the bracket plate (20), the bracket plate (20) rises to send the workpiece between the two clamping tubes (8), the two clamping tubes (8) move relative to each other in the front-back direction and clamp the workpiece from the first direction through the clamping plate (19), the bracket plate (20) falls back to its original position, the first direction is the front-back direction; S2: The infrared heating component (16) preheats the opposite two sides of the workpiece. The workpiece is rotated by the clamping tube (8) to expose the unheated surface to the heating area of ​​the infrared heating component (16) until each surface of the workpiece to be coated reaches the predetermined preheating temperature. S3: The spray gun sprays each surface to be coated sequentially; S4: The bracket plate (20) rises to support the workpiece, the two clamping tubes (8) move in opposite directions along the front-back direction to release the workpiece, the bracket plate (20) rotates 90°, the two clamping tubes (8) move relative to each other again along the front-back direction and clamp the workpiece from the second direction, the second direction being the direction perpendicular to the first direction, and the bracket plate (20) descends to reset. S5: Repeat steps S2 and S3 to preheat and spray the remaining uncoated surfaces of the workpiece. S6: The infrared heating component (16) heats the interior of the sealed box (2) to the polyphenylene sulfide curing temperature and keeps it warm, so that the coating is cured as a whole.

10. The process for preparing a polyphenylene sulfide anti-corrosion coating according to claim 9, characterized in that: In step S2, the predetermined preheating temperature is 300°C to 350°C; in step S6, the polyphenylene sulfide curing temperature is 320°C to 340°C, and the heat preservation time is 15 to 60 minutes.

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