An on-line coating system for pultruded and / or extruded profiles

Abstract

The present application relates to the coating technical field of pultrusion and / or extrusion profiles, in particular to an online coating system for pultrusion and / or extrusion profiles, comprising a coating working box, the inlet and outlet of the coating working box are provided with high-precision molds, which are inlet mold and outlet mold respectively, the inlet mold and outlet mold are matched with the cross section of the profile, the inlet mold is a slope mold with outer wide and inner narrow, the outlet mold is a slope mold with inner wide and outer narrow, the coating working box is connected with a drying device through the outlet mold, and the coating working box is connected with a paint circulation recycling device through a collection hole; the system can be directly arranged on the pultrusion or extrusion profile production line, realizes continuous online coating, positions through the high-precision mold and accurately controls the film thickness, avoids the problems of sagging and uneven film thickness, is suitable for complex cross-section profiles, has high paint utilization rate, low emission and loss, occupies less space, and has good film appearance and performance.

Description

Technical Field

[0001] This invention relates to the field of coating technology for pultruded and / or extruded profiles, and more specifically to an online coating system for pultruded and / or extruded profiles. Background Technology

[0002] Coating of pultruded and / or extruded profiles generally involves cutting, storing, and transferring the continuously produced profiles to a coating production line, where coating is completed through spraying, electrophoresis, dip coating, or curtain coating.

[0003] However, conventional profile spraying is mainly divided into the following types: (1) Vertical spraying: The produced profiles are first cut into a certain length and then transferred to the coating line for hanging. Multiple spray guns are set in the coating room. After spraying and drying, they are packaged off the line. The vertical coating line needs to be higher than the profile and leave enough space for operation and movement, so it is very high and long; (2) Horizontal spraying: The produced profiles are first cut into a certain length and then transferred to the coating line for flat placement. Spray guns are set in the upper part of the coating room. The front is sprayed first, then the back is flipped and sprayed, and then dried and packaged off the line. The horizontal coating line is very wide and needs to be greater than the length of the profile plus the equipment space. The horizontal production line including flipping and leveling is very wide and long; (3) Curtain coating: It is usually similar to horizontal spraying. After the front is sprayed, it needs to be flipped and then the back is sprayed. The coating film is prone to dripping, uneven film thickness, etc., and the appearance is difficult to control; (4) Dip coating: It is highly efficient and each side can be painted at the same time, but the coating film is prone to dripping, uneven film thickness, etc., and the appearance is usually poor. In addition, all of the above-mentioned spraying methods have the disadvantage of low paint utilization.

[0004] Chinese patent CN219664193U discloses an online drawing coating device for photovoltaic frames, which is used in a pultrusion production line for photovoltaic frames to perform online drawing coating on pultruded photovoltaic frames. The device includes an online coating mechanism and a drying mechanism arranged along the drawing direction of the photovoltaic frame. The online coating mechanism includes a housing, in which an elastic coating body, a roller coating mechanism, and a scraper are sequentially arranged along the drawing direction of the photovoltaic frame. A material recovery mechanism is located below the roller coating mechanism and the scraper. This device is suitable for coating simple profiles such as square and round tubes. However, frame profiles have many folded edges and baffles, forming multiple right-angled surfaces and deep grooves, making it difficult for the sponge elastomer, roller coating mechanism, and scraper to precisely adhere to the various coating surfaces of the profile and effectively control the coating thickness and appearance in actual operation.

[0005] To this end, we propose an online coating system for pultruded and / or extruded profiles. Summary of the Invention

[0006] In view of this, the present invention provides an online coating system for pultruded and / or extruded profiles, which aims to solve the above-mentioned technical problems.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: An online coating system for pultruded and / or extruded profiles includes a coating work box. The coating work box has high-precision molds at both its inlet and outlet, designated as an inlet mold and an outlet mold, respectively. Both the inlet and outlet molds are matched to the cross-section of the profile. The inlet mold is a sloped mold with a wider outer edge and a narrower inner edge, and the outlet mold is a sloped mold with a wider inner edge and a narrower outer edge. The coating work box is connected to a drying device via the outlet mold, and the bottom of the coating work box is connected to a paint recycling device via a collection hole.

[0008] In some embodiments, both the inlet mold and the outlet mold are provided with positioning guide grooves for the profile to pass through, and the positioning guide grooves are matched with the cross-section of the profile.

[0009] In some embodiments, the high-precision mold is a fluororubber mold, a silicone rubber mold, or a metal mold, and the high-precision mold is manufactured by 3D printing or machining.

[0010] In some embodiments, the gap between the inner side of the inlet mold and the profile is 50-200 μm, and the gap between the outer side of the outlet mold and the profile is 30-150 μm.

[0011] In some embodiments, the coating work box is a stainless steel work box, an aluminum alloy work box, a polypropylene work box, a polyethylene work box, a fluororubber work box, or a silicone rubber work box.

[0012] In some embodiments, the coating work box is one of a closed spray box, an immersion coating working fluid tank, or a multi-directional spray coating working fluid tank.

[0013] In some embodiments, the enclosed spray box is provided with multi-directional spray guns on multiple sides.

[0014] In some embodiments, the drying device includes an inner shell and an outer shell, with a profile passing through the inner shell, and an electric heating tube, a steam jacket heating tube, or a heat transfer oil heating tube disposed between the inner shell and the outer shell.

[0015] In some embodiments, the drying device is connected to an air transmission pipe via an air inlet and to an exhaust gas transmission pipe via an air outlet.

[0016] In some embodiments, the online coating system further includes an online switching and cleaning device, which includes a standby coating device and a circulating cleaning device configured along the profile production line.

[0017] As can be seen from the above technical solution, compared with the prior art, the present invention discloses an online coating system for pultruded and / or extruded profiles, which has the following beneficial effects: 1. The online coating system of this invention is directly installed on the pultrusion or extrusion profile production line. The profiles continuously pass through the coating work box and drying device, eliminating the need for offline transfer and coating after cutting. This achieves continuous online coating of the profiles, resulting in high production efficiency and minimal space occupation. The coating work box is equipped with high-precision molds at both the inlet and outlet. The inlet mold has an outer wider and inner narrower slope to guide the profiles in, while the outlet mold has an inner wider and outer narrower slope to scrape off excessive paint. The high-precision molds position the profiles and precisely control the film thickness, avoiding the sagging and uneven film thickness problems caused by dip coating and spray coating. It also eliminates the need for precise control of the spray coating film thickness, simplifying the coating process and resulting in good coating appearance and performance. At the same time, the positioning guide grooves of the high-precision molds match the cross-section of the profiles. Molds can be customized for profiles with complex structures such as folded edges, right angles, and deep grooves, ensuring effective coating and film thickness control on all coating surfaces. This system is suitable for profiles with complex cross-sections.

[0018] 2. In this invention, the bottom of the coating work box is connected to a paint recycling device via a collection hole. Excess paint can be recycled and reused, and the excessive paint scraped off the exit mold is also returned to the work box for recycling, which greatly improves the paint utilization rate and reduces emissions and losses. The coating work box can be a closed spray box, an immersion coating working liquid tank, or a multi-directional spray coating working liquid tank. It can be flexibly selected according to the product coating performance requirements and paint characteristics, and has a wide range of applications. It is equipped with an online switching and cleaning device, which can quickly change the coating equipment without stopping the machine. It is convenient for mold wear replacement, paint drying and cleaning, and two-component paint timed cleaning, ensuring continuous production. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall process of the online coating system of the present invention.

[0021] Figure 2 This is a schematic diagram of the drying apparatus of the present invention.

[0022] Figure 3 This is a cross-sectional view of the coating work box of the present invention.

[0023] Figure 4 This is a schematic diagram of the paint recycling device of the present invention. Figure 5 This is a schematic diagram of the imported mold of the present invention; Figure 6This is a front view of the painting work box with a multi-directional spray gun according to the present invention; Figure 7 This is a schematic diagram of the online switching and cleaning device of the present invention.

[0024] in: 1. Profiles; 2. Painting work box; 3. Imported molds; 4. Exported molds; 5. Drying device; 6. Paint recycling device; 7. Collection hole; 8. Positioning guide groove; 9. Inner shell; 10. Outer shell; 11. Heating tube; 12. Air inlet; 13. Air outlet; 14. Multi-directional spray gun; 15. Online switching and cleaning device; 16. Backup painting equipment; 17. Circulating cleaning device. Detailed Implementation

[0025] 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.

[0026] Please see Figure 1-7 The present invention provides an online coating system for pultruded and / or extruded profiles. In this embodiment, the online coating system is directly arranged on the continuous production line of pultruded or extruded profile 1. After surface pretreatment (such as degreasing, washing and passivation treatment of aluminum alloy extruded window frames), the profile 1 directly enters the coating system without cutting, storage and offline transfer.

[0027] The online coating system of this embodiment includes a coating work box 2, which is made of stainless steel and has a closed spray box structure. The inlet and outlet ends of the coating work box 2 are respectively equipped with high-precision molds, namely inlet mold 3 and outlet mold 4. Both inlet mold 3 and outlet mold 4 are made of fluororubber and are formed by 3D printing or precision machining. Both inlet mold 3 and outlet mold 4 are provided with positioning guide grooves 8 for profile 1 to pass through. The cross-sectional contour of the positioning guide groove 8 is completely matched with the cross-section of profile 1. The profile 1 has corresponding positioning and scraping working surfaces for complex structural parts such as folded edges, baffles, right angle surfaces and deep grooves.

[0028] The imported mold 3 has a sloping structure that is wider on the outside and narrower on the inside. The gap between its inner side and the profile 1 is controlled within 50-200μm. The specific gap value can be adjusted within this range according to the cross-sectional structure of the profile 1 and the viscosity of the coating. After the profile 1 is continuously extruded from the production line, it first enters the imported mold 3. The imported mold 3, through its sloping guide structure and internal positioning function, accurately guides the continuously moving profile 1 into the coating work box 2, ensuring that the profile 1 always passes along the central axis of the box, avoiding deviation or shaking of the profile 1 that would affect the coating accuracy.

[0029] The interior of the painting work box 2 is a closed spraying space. Multi-directional spray guns 14 are installed on each of the four sides (top, bottom, left, and right) of the box. The spraying directions of the multi-directional spray guns 14 are respectively aimed at each surface of the profile 1. As the profile 1 passes through the painting work box 2, the multi-directional spray guns 14 are simultaneously activated, spraying the top, bottom, left, and right surfaces of the profile 1 at the same time, ensuring that each surface of the profile 1 is fully and evenly coated. In this embodiment, water-based acrylic baking paint is used as the coating material, with a solid content of approximately 45%–55% and a viscosity controlled at 25–35 seconds (Ford Cup 4).

[0030] After being fully sprayed by the multi-directional spray gun 14, the profile 1 with a relatively thick wet coating film continuously enters the exit mold 4. The exit mold 4 has an inclined structure that is wider on the inside and narrower on the outside, and the gap between its outer side and the profile 1 is precisely controlled at 30-150μm. Through its internal positioning and precise gap control functions, the exit mold 4 uniformly scrapes off the excessively thick coating on each surface of the profile 1 when the profile 1 exits the coating work box 2, leaving only a coating with the same thickness as the gap of the exit mold 4. During this process, the scraped excess coating flows back along the inner wall of the exit mold 4 to the bottom of the coating work box 2, avoiding coating waste. By adjusting the fit gap between the exit mold 4 and each surface of the profile 1, the final wet film thickness (usually controlled at 60-120μm) can be precisely controlled according to the product coating design requirements, and then a dry film thickness (about 25-60μm) matching the design requirements can be obtained after curing. At the same time, the precise scraping process of the exit mold 4 makes the coating surface smooth and flat, effectively eliminating appearance defects such as sagging, dripping, and orange peel that are common in dip coating or spray coating methods.

[0031] The bottom of the coating work box 2 is provided with a collection hole 7, which is connected to the paint recycling device 6 through a pipe. The paint collected at the bottom of the coating work box 2 (including the paint dripping after spraying by the multi-directional spray gun 14 and the paint scraped back by the exit mold 4) flows into the paint recycling device 6 through the collection hole 7. After removing particulate impurities and air bubbles through online filtration, it is transported back to the paint supply system of the multi-directional spray gun 14 by a circulation pump for recycling. In the entire coating process, the paint utilization rate reaches more than 90%, which is significantly higher than that of traditional spraying methods (usually only 40% to 60%), greatly reducing paint consumption and waste paint discharge.

[0032] After being precisely coated by the exit mold 4, the profile 1, carrying a uniform wet coating film that meets the film thickness requirements, immediately enters the drying device 5. The drying device 5 is located after the coating work box 2, and the two are directly connected by the exit mold 4. The drying device 5 adopts a double-shell structure, including an inner shell 9 and an outer shell 10. The profile 1 passes through the inside of the inner shell 9. An electric heating tube 11 is provided between the inner shell 9 and the outer shell 10 as a heating source. The heating temperature can be adjusted according to the characteristics of the coating. In this embodiment, the electric heating tube 11 controls the internal temperature of the drying device 5 between 120 and 180°C. The profile 1 passes through the drying device 5 continuously at a linear speed of 0.5 to 2.0 m / min. The wet coating film is rapidly cured and cross-linked under heating conditions to form a dense dry coating film.

[0033] The drying device 5 is also equipped with an air inlet and outlet system. The air inlet 12 of the drying device 5 is connected to an air transmission pipe to supply fresh air into the drying device 5 to maintain hot air circulation. The air outlet 13 of the drying device 5 is connected to an exhaust gas transmission pipe to discharge water vapor, a small amount of organic solvent vapor and hot air volatilized during the curing process. The exhaust gas transmission pipe is further connected to an exhaust gas treatment system (such as a VOCs catalytic combustion device or an activated carbon adsorption device) to ensure that the exhaust gas is discharged after environmental protection treatment to meet the standards, thus ensuring that the production process complies with environmental emission standards.

[0034] After curing in drying unit 5, profile 1 is continuously output. After being cooled to room temperature by air or wind, it is cut to a fixed length online according to product specifications. After passing inspection, it is packaged and stored. The entire coating process, from extrusion of profile 1 to finished product packaging, is a fully continuous operation. There are no intermediate processes such as cutting, storage, transfer, or re-hanging. The length of a single coating production line is only about 15 to 25 meters (depending on the length of the drying section). Compared with traditional vertical coating lines (usually over 20 meters in height) and horizontal coating lines (usually over 50 meters in length), the space occupied is greatly reduced, and the production efficiency and automation level are significantly improved.

[0035] In actual production, when it is necessary to change the paint color or type, or when high-precision molds wear down due to long-term continuous production, or when paint dries and adheres to the inner wall of the coating work box 2, affecting the quality of the coating film, the online coating system of this embodiment is equipped with an online switching and cleaning device 15. Specifically, two coating work boxes 2 are arranged laterally along the profile 1 production line, and online switching is controlled by a lifting mechanism: one is in a high position for coating work, and the other is in a low position for standby. When the coating work box 2 in operation needs to be stopped for cleaning or mold replacement, the standby coating work box 2 is raised to the working position by the lifting mechanism, and the original work box is lowered simultaneously. The entire process can be completed without stopping the machine or affecting the continuous operation of the production line. The coating work box 2 that is switched off first recovers the residual paint to the paint recycling device 6, and then connects to the circulating cleaning device 17. The circulating cleaning device 17 includes two parts: rough cleaning and fine cleaning. The rough cleaning uses high-pressure solvent spraying to quickly remove the residual paint from the inner wall of the coating work box 2 and the surface of the mold. The fine cleaning uses ultrasonic cleaning combined with fine filtration solvent circulation to thoroughly remove tiny residual paint residues. After the fine cleaning is completed, the condition of each component of the high-precision mold and the coating work box 2 is checked, and worn or deformed parts are replaced in time for use in the next switchover.

[0036] The online coating system of this embodiment is applicable to pultruded and / or extruded profiles 1 with various cross-sectional shapes, especially profiles 1 with complex cross-sections such as folded edges, baffles, multiple right angles and deep grooves (such as aluminum alloy window frames, photovoltaic frames, composite material cable trays, etc.). For different cross-sectional profiles 1, only the imported mold 3 and the export mold 4 that match the cross-section need to be replaced. The coating work box 2 and the drying device 5 do not need to be modified, and different specifications of products can be quickly produced, which greatly improves the flexible production capacity of the production line.

[0037] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0038] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0039] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An online coating system for pultruded and / or extruded profiles, comprising a coating work box (2), characterized in that: The coating work box (2) is equipped with high-precision molds at both the inlet and outlet, namely an inlet mold (3) and an outlet mold (4). The inlet mold (3) and the outlet mold (4) are matched with the cross-section of the profile (1). The inlet mold (3) is a slope mold with a wider outer side and a narrower inner side, and the outlet mold (4) is a slope mold with a wider inner side and a narrower outer side. The coating work box (2) is connected to the drying device (5) through the outlet mold (4), and the bottom of the coating work box (2) is connected to the paint recycling device (6) through the collection hole (7).

2. The online coating system for pultruded and / or extruded profiles according to claim 1, characterized in that: Both the inlet mold (3) and the outlet mold (4) are provided with positioning guide grooves (8) through which the profile (1) passes, and the positioning guide grooves (8) are matched with the cross-section of the profile (1).

3. The online coating system for pultruded and / or extruded profiles according to claim 1, characterized in that: The high-precision mold is a fluororubber mold, a silicone rubber mold, or a metal mold, and is manufactured by 3D printing or machining.

4. The online coating system for pultruded and / or extruded profiles according to claim 1, characterized in that: The gap between the inner side of the inlet mold (3) and the profile (1) is 50-200μm, and the gap between the outer side of the outlet mold (4) and the profile (1) is 30-150μm.

5. The online coating system for pultruded and / or extruded profiles according to claim 1, characterized in that: The coating work box (2) is a stainless steel work box, an aluminum alloy work box, a polypropylene work box, a polyethylene work box, a fluororubber work box, or a silicone rubber work box.

6. The online coating system for pultruded and / or extruded profiles according to claim 1, characterized in that: The coating work box (2) is one of a closed spray box, an immersion coating working liquid tank or a multi-directional spray coating working liquid tank.

7. The online coating system for pultruded and / or extruded profiles according to claim 6, characterized in that: The enclosed spray box is equipped with multi-directional spray guns (14) on multiple sides.

8. The online coating system for pultruded and / or extruded profiles according to claim 1, characterized in that: The drying device (5) includes an inner shell (9) and an outer shell (10). A profile (1) passes through the inner shell (9). An electric heating tube (11), a steam jacket heating tube (11) or a heat transfer oil heating tube (11) is provided between the inner shell (9) and the outer shell (10).

9. The online coating system for pultruded and / or extruded profiles according to claim 1, characterized in that: The drying device (5) is connected to an air transmission pipe via an air inlet (12) and to an exhaust gas transmission pipe via an air outlet (13).

10. The online coating system for pultruded and / or extruded profiles according to claim 1, characterized in that: The online coating system also includes an online switching and cleaning device (15), which includes a standby coating equipment (16) and a circulating cleaning device (17) configured along the profile (1) production line.

Images