A method of coating a pipe

Abstract

The application discloses a pipe coating method, which comprises the following steps: making a film enter a film guide groove, making a pipe synchronously pass through the film guide groove, making the film be located at the bottom surface of the pipe, and making the two sides of the film be respectively located at the two sides of the pipe; making the film be tightened and coated on the two side walls of the pipe through a film guide tensioning structure at the rear side of the film guide groove; making the two edge sections of the film be tightened and form a film overlapping part on the front surface of the pipe through a film superposition guide structure; and performing hot fusion at the film overlapping part, so that the pipe coating is completed. The pipe coating method provided by the application can greatly reduce the use amount of the film, reduce the cost, and is beneficial to improving the pipe conveying speed and has high coating efficiency.

Description

Technical Field

[0001] The present invention relates to the field of pipe packaging technology, in particular to a pipe film wrapping method. Background Art

[0002] After forming square tubes, round tubes, or other strip-shaped materials, a protective film is typically wrapped around the surface to prevent surface defects such as scratches caused by friction or collision during transportation. Currently, the equipment used to wrap film around tubes is typically divided into two types: shrouding machines and film wrapping machines. Shrouding machines apply a cylindrical film directly to the outside of the tube, while film wrapping machines wrap a sheet of film around the outside of the tube and then heat-weld the overlapping edges of the film.

[0003] However, in order for the film-making machine to smoothly cover the tubular film on the outside of the pipe, a large gap needs to be left between the pipe and the film.

[0004] However, after the existing coating machine wraps the sheet film around the outside of the pipe, there is still a large gap between the film and the pipe because the film is not tightly wrapped. In order to ensure that the width of the film overlap is sufficient for heat fusion and reduce the chance of the film overlap accidentally loosening after heat fusion, an additional width of 30-40 mm needs to be reserved for the film overlap when coating the pipe.

[0005] The two aforementioned methods of wrapping pipes with film are not only prone to slippage between the pipe and the film during transportation, and the film ends are easily cut, but also result in large amounts of film used, resulting in waste and high packaging costs. Furthermore, when the film wrapping machine is operating, the film adheres poorly to the pipe. If the pipe is conveyed at excessive speeds, this compromises the weld stability of the film overlap. Consequently, the pipe conveying speed is limited to below 20 m / min, resulting in low film wrapping efficiency. Summary of the Invention

[0006] The purpose of the present invention is to provide a pipe coating method that can significantly reduce the amount of film used and reduce costs, while also being conducive to increasing the pipe conveying speed and achieving high coating efficiency.

[0007] To achieve the above-mentioned purpose, the present invention provides a pipe wrapping method, which allows the film to enter the film guide groove, allows the pipe to pass through the film guide groove synchronously, allows the film to be located on the bottom surface of the pipe, and at the same time allows the two side parts of the film to be located on both sides of the pipe respectively; at the rear side of the film guide groove, the film is first tightened and wrapped to fit the two side walls of the pipe through the film guide tensioning structure, and then the two edge sections of the film are tightened on the front of the pipe through the film overlapping guide structure to form a film overlapping part, and then the film overlapping part is heat-fused to complete the pipe wrapping.

[0008] As a further improvement of the present invention, the film guiding and tensioning structure includes at least one group of first rollers symmetrically arranged on both sides of the tube, and the film is pressed against the side wall of the tube by the first rollers. The rolling tangent direction of the first roller on the film and the conveying direction of the tube form an acute angle α, so that when the first roller rotates, a tensioning force is formed on the film toward the side where the front of the tube is located.

[0009] As a further improvement of the present invention, there is elastic contact between the first roller and the film; and the pressure exerted by the first roller on the tube is adjustable.

[0010] As a further improvement of the present invention, the spacing between the first rollers is adjustable, and the size of the acute angle α is adjustable.

[0011] As a further improvement of the present invention, the first roller is linked with a first active driving mechanism.

[0012] As a further improvement of the present invention, the film stacking guide structure presses the two edge segments of the film against the front of the tube through the second roller and the third roller respectively. The rolling tangent direction of the second roller and the third roller on the film and the conveying direction of the tube form an acute angle β, so that the second roller and the third roller can form a tensioning force on the film toward the middle of the front of the tube when they rotate.

[0013] As a further improvement of the present invention, the second roller and the third roller avoid the overlapping portion of the film when they respectively contact the two edge segments of the film. The lateral spacing between the second roller and the third roller is adjustable; and the size of the acute angle β is adjustable.

[0014] As a further improvement of the present invention, the second roller and the third roller are in elastic contact with the film. The pressure exerted by the second roller and the third roller on the pipe is adjustable.

[0015] As a further improvement of the present invention, the second roller is linked to a second active driving mechanism, and the third roller is linked to a third active driving mechanism.

[0016] As a further improvement of the present invention, the thermal fusion is one of laser welding and ultrasonic welding.

[0017] Beneficial effects

[0018] Compared with the prior art, the advantages of the pipe coating method of the present invention are:

[0019] 1. When the pipe passes through the film guide groove, the film guide groove allows the film to bend into a U shape and wrap around the outside of the pipe. The film guide tensioning structure then allows the film to wrap and fit on both side walls of the pipe. The film overlapping guide structure then tightens the two edge segments of the film on the front of the pipe to form a film overlap, and then heat-fusing the film at the overlap. After the film is coated using this method, the film has a high degree of fit with the outer wall of the pipe, and the required width of the film overlap for welding is small, only about 5-10 mm is needed. Therefore, the width of the sheet film required for each pipe is small, and the packaging cost is also lower. By setting up a film overlapping guide structure, the degree of fit at the film overlap is high, and the efficiency and speed of heat fusion can also be improved. At this time, even if the pipe conveying speed is increased to more than 60m / min, a high degree of film heat fusion stability can be ensured, which is conducive to improving production efficiency.

[0020] 2. There is an acute angle α between the rolling tangent direction of the first roller on the film and the conveying direction of the pipe, and an acute angle β between the rolling tangent direction of the second and third rollers on the film and the conveying direction of the pipe. The pipe can drive the rollers to roll when it is conveyed, and the tangential force of the rollers when they roll can tighten the film so that it fits the outer surface of the pipe as much as possible.

[0021] 3. When the second roller and the third roller contact the two edge sections of the film respectively, they avoid the overlapping portion of the film, which can prevent the second roller and the third roller from tightening the film on the same side while affecting the tension of the other side of the film.

[0022] 4. The first roller, the second roller and the third roller are in elastic contact with the film, which is conducive to pressing the film.

[0023] The present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, which are used to illustrate embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 This is a right side view of the pipe fitting coating head of Example 1;

[0026] Figure 2 A top view of the film guide groove of Example 1;

[0027] Figure 3 A top view of the film guide tensioning structure of Example 1;

[0028] Figure 4 This is a right view of the film guide and tensioning structure of Example 1 in working state;

[0029] Figure 5 A partial three-dimensional diagram of the film stacking guide structure of Example 1;

[0030] Figure 6 A top view of the film and tube coating process of Example 1;

[0031] Figure 7 This is a right side view of the pipe packaging production line of Example 1;

[0032] Figure 8 This is a rear view of the first roller, the second roller, the third roller, and the pipe fitting of Example 1;

[0033] Figure 9 It is a right side view of the pipe fitting coating head of Example 2;

[0034] Figure 10 This is a rear view of the first roller, the second roller, the third roller, and the pipe fitting of Example 2;

[0035] Figure 11 Schematic diagram of the baffle in Example 3. DETAILED DESCRIPTION

[0036] Embodiments of the present invention will now be described with reference to the accompanying drawings.

[0037] Example 1

[0038] The specific embodiments of the present invention are as follows Figures 1 to 8 As shown, a method for wrapping a pipe fitting is shown, wherein a film 10 is introduced into a film guide groove 1, and a pipe fitting 9 is simultaneously passed through the film guide groove 1, so that the film 10 is located on the bottom surface of the pipe fitting 9, and at the same time, the two side portions of the film 10 are located on both sides of the pipe fitting 9. At the rear side of the film guide groove 1, the film 10 is first tightened and wrapped around the two side walls of the pipe fitting 9 by a film guide tensioning structure 2. Then, the two edge segments of the film 10 are tightened on the front side of the pipe fitting 9 by a film laminating guide structure 3 to form a film overlap 101. Then, the film overlap 101 is thermally fused to complete the pipe fitting wrapping. The bottom surface of the pipe fitting 9 is not necessarily the bottommost surface of the pipe fitting 9, and the front surface of the pipe fitting 9 is not necessarily the topmost surface of the pipe fitting 9. The bottom surface of the pipe fitting 9 faces the inner bottom of the film guide groove 1, while the front surface of the pipe fitting 9 faces opposite directions from the bottom surface of the pipe fitting 9.

[0039] The film guide tensioning structure 2 includes at least one set of first rollers 21 symmetrically arranged on both sides of the tube. The two first rollers 21 press the film 10 against the side wall of the tube 9. The rolling tangent direction of the first rollers 21 on the film 10 forms an acute angle α with the conveying direction of the tube 9, so that when the first rollers 21 rotate, a tension force is applied to the film 10 toward the front side of the tube 9. Figure 4 In the figure, two arrows forming an acute angle α are parallel to the conveying direction of the tube 9, and the other is parallel to the tangential direction of the first roller 21 on the rolling film, which is perpendicular to the axis of the first roller 21.

[0040] The film stacking guide structure 3 presses the two edge sections of the film 10 against the front surface of the tube 9 through the second roller 31 and the third roller 32. The rolling tangent direction of the second roller 31 and the third roller 32 on the film 10 forms an acute angle β with the conveying direction of the tube 9, so that the second roller 31 and the third roller 32 can exert a tension on the film 10 toward the middle of the front surface of the tube 9 when they rotate. Figure 6 In the figure, two arrows forming an acute angle β are shown, one of which is parallel to the conveying direction of the tube 9 and the other is parallel to the tangential direction of the second roller 31 on the rolling film, which is perpendicular to the axis of the second roller 31.

[0041] When the second and third rollers 31 and 32 contact the two edge sections of the film 10, they avoid the film overlap 101. The lateral spacing between the second and third rollers 31 and 32 is adjustable. Specifically, the second base 33 is slidably connected to the pressure plate 16, and a position locking mechanism is provided between the two. The position locking mechanism can be bolted to lock the second base 33 to the pressure plate 16.

[0042] The first roller 21, the second roller 31 and the third roller 32 are in elastic contact with the film 10. The pressure exerted by the first roller 21 on the pipe 9 is adjustable. The pressure exerted by the second roller 31 and the third roller 32 on the pipe 9 is adjustable.

[0043] When the first roller 21, the second roller 31, and the third roller 32 are insufficiently tightening the film 10 due to a slow conveying speed of the tube 9 or other reasons, the rollers can be linked with active drive mechanisms to enable each roller to rotate autonomously. Specifically, the first roller 21 is linked with a first active drive mechanism, the second roller 31 is linked with a second active drive mechanism, and the third roller 32 is linked with a third active drive mechanism. The autonomous rotation of each roller increases the tension on the film 10.

[0044] Thermal fusion is either laser welding or ultrasonic welding. In this embodiment, thermal fusion is performed by laser welding, whereby the surface of the film overlap portion 101 is welded by laser. Since laser welding is a non-contact welding method, it does not adhere to welding slag, and the welding speed is fast. Even long-term and multiple welding operations will not reduce the weld strength.

[0045] To implement the aforementioned tube wrapping method, a tube wrapping head is employed. The head comprises a film guide trough 1, a film guide tensioning structure 2, and a film stacking guide structure 3, arranged sequentially along the travel direction of the tube 9. The film stacking guide structure 3 comprises a second roller 31 and a third roller 32. The rolling tangents of the second and third rollers 31, 32 on the film 10 form an acute angle β with the conveying direction of the tube 9.

[0046] In order to avoid the film overlap 101 and prevent the second roller 31 and the third roller 32 from tightening the film 10 on the same side while affecting the tension of the film 10 on the other side, a film overlap avoidance gap D is left between the projections of the adjacent ends of the second roller 31 and the third roller 32 along the conveying direction of the tube 9. Figure 6 shown.

[0047] The film stacking guide structure 3 also includes a second base 33, on which a second roller 31 and a third roller 32 are mounted. A second elastic member 34 is connected between the second roller 31 and the third roller 32 and the second base 33. The rotating shafts of the second roller 31 and the third roller 32 are respectively mounted on respective second roller frames 36, which are slidably engaged with the second base 33. The second elastic member 34 is connected between the second base 33 and the second roller frame 36.

[0048] In addition, the second roller 31 and the third roller 32 can also be made of elastic material. In this case, even if the film stacking guide structure 3 does not use the second elastic member 34 , it can ensure that the second roller 31 and the third roller 32 are in elastic contact with the film 10 .

[0049] The film guiding and tensioning structure 2 includes first rollers 21 corresponding to both side walls of the tube 9 . The rolling tangent direction of the first rollers 21 on the film 10 forms an acute angle α with the conveying direction of the tube 9 .

[0050] The film guide and tensioning structure 2 also includes two symmetrically arranged first bases 22. The first bases 22 are connected to the first rollers 21 via first elastic members 23. Specifically, the rotating shaft of each first roller 21 is mounted on a first roller frame, which slidably engages with the first base 22. The first elastic member 23 is connected between the first roller frame and the first base 22.

[0051] The spacing of a group of first rollers 21 is adjustable. The film guide tensioning structure 2 also includes a slide rail 24, and the two first bases 22 are both slidably connected to the slide rail 24. A spacing adjustment structure is provided between the first base 22 and the slide rail 24. In this embodiment, the spacing adjustment structure can be formed by a connected screw and a handwheel (not shown in the figure). The screw is threadedly connected to the two first bases 22 respectively, and the threads of the two first bases 22 are rotated in opposite directions. By rotating the screw with the handwheel, the two first rollers 21 can be moved closer to or farther away from each other, thereby adapting to pipes 9 of different sizes. At the same time, the pressure exerted on the pipe 9 by a group of two first rollers 21 can be adjusted.

[0052] A heat-melting structure 6 is provided on the rear side of the film stacking guide structure 3. In this embodiment, the heat-melting structure 6 is a laser welding head. The film guide groove 1 includes a connecting plate 12. Two limiting plates 11 are provided on the same side of the connecting plate 12. The two limiting plates 11 include a triangular film guide portion 111 located at the front end thereof. An arc-shaped film guide portion 13 is provided in front of the two limiting plates 11. The spacing between the two limiting plates 11 is adjustable to accommodate pipes 9 of different widths. The arc-shaped film guide portion 13 is an arc-shaped rod. When the film unwinding mechanism 5 is in front of the film guide groove 1, the film 10 enters the film guide groove 1 from the front of the film guide groove 1. In this case, the arc-shaped film guide portion 13 located at the front end of the connecting plate 12 can be omitted. In this embodiment, since the film unwinding mechanism 5 is located below the film guide groove 1, the film 10 needs to go around the front end of the connecting plate 12 to enter the film guide groove 1. At this time, an arc-shaped film guide part 13 needs to be set. The arc-shaped rod of the arc-shaped film guide part 13 can guide the turning of the film 10.

[0053] The tube film coating head also includes a first tube pressing structure 14, a second tube pressing structure 15 and a pressure plate 16. The pressure plate 16 is connected to a driving device. Specifically, the driving device can be a lifting mechanism. The first tube pressing structure 14 and the second tube pressing structure 15 are arranged relative to each other, and the film stacking guide structure 3, the heat fusion structure 6 and the first tube pressing structure 14 are all arranged on the pressure plate 16. In this embodiment, the first tube pressing structure 14 is a pressure wheel, and the second tube pressing structure 15 includes a matching belt and pulley set. The belt and pressure wheel clamp the tube 9 in the middle to achieve a limiting effect on the tube 9. The driving device of the pressure plate 16 can drive the pressure plate 16 to move, so that the belt of the second tube pressing structure 15 approaches or moves away from the pressure wheel of the first tube pressing structure 14, and can also adjust the pressure of the second roller 31 and the third roller 32 on the tube 9. The heat fusion structure 6 and the second base 33 of the film stacking guide structure 3 are also installed on the pressure plate 16.

[0054] Both acute angles α and β can be set to be adjustable. Specifically, the first base 22 may include a first base body and a first slider, the first slider slidably engaged with the slide rail 24. The first wheel frame of the first roller 21 is connected to the first base body via a first elastic member 23. The first base body and the first slider are rotationally connected and provided with a first angle locking structure. The second base 33 may include a second base body and a second slider, the second slider slidably engaged with the pressure plate 16. The second wheel frames 36 of the second roller 31 and the third roller 32 are connected to the second base body via a second elastic member 34. The second base body and the second slider are rotationally connected and provided with a second angle locking structure. The first angle locking structure and the second angle locking structure can both use screws. The screw of the first angle locking structure is threadedly connected to the first slider and one end of the screw is in contact with the first base body. The screw of the second angle locking structure is threadedly connected to the second slider and one end of the screw is in contact with the second base body. By tightening the screw, the screw is pressed against the base body and the relative angle between the slider and the base body is locked, so that the size of the acute angle α and the acute angle β can be adjusted, thereby facilitating the operator to select the most appropriate acute angle α and acute angle β.

[0055] In the pipe wrapping head of this embodiment, the connecting plate 12 of the film guide groove 1 is arranged horizontally, the two limit plates 11 are both located above the connecting plate 12, the pressing plate 16, the heat fusion structure 6, the film overlapping guide structure 3, and the first pressing tube structure 14 are all located above the second pressing tube structure 15. At this time, the bottom surface of the pipe 9 faces downward and the front surface of the pipe 9 faces upward.

[0056] The pipe wrapping head can be used in a pipe packaging production line, which includes a pipe loader 7 and a pipe strapping machine 8. The pipe loader 7, pipe wrapping head, and pipe strapping machine 8 are arranged sequentially along the conveying direction of pipes 9. A film unwinding mechanism 5 is also provided on one side of the pipe wrapping head. The film unwinding mechanism 5, film guide trough 1, film guide and tensioning structure 2, film stacking guide structure 3, pressing plate 16, first pipe pressing structure 14, and second pipe pressing structure 15 are all mounted on the wrapping head base 4. The film unwinding mechanism 5 is located below the film guide trough 1.

[0057] During operation, the tube is loaded by the tube loader 7 and passed through the film guide groove 1 of the tube wrapping head. Film 10 is unwound by the film unwinding mechanism 5, first around the front of the curved film guide 13, then around the upper edge of the triangular film guide 111, and into the film guide groove 1. The film 10 winds to the underside of the tube 9 (i.e., the bottom surface of the tube 9), with the film 10's two side sections positioned on the left and right sides of the tube 9. The film 10's two side sections are then wound upward by the first roller 21 to the top surface of the tube 9 (i.e., the front surface of the tube 9). The film lamination guide structure 3 then presses the two edge sections of the film 10 against the front surface of the tube 9 using the second roller 31 and the third roller 32, tightening them and forming a film overlap 101. The heat-sealing structure 6 then heat-seals the film overlap 101, completing the film wrapping of the tube 9. The wrapped tube 9 is then conveyed to the tube bundling machine 8 for bundling. In this embodiment, the tube 9 is a square tube.

[0058] Example 2

[0059] like Figure 9 As shown, the difference from Example 1 is that in the tube wrapping head of this embodiment, the connecting plate 12 of the film guide groove 1 is arranged horizontally, the two limit plates 11 are both located below the connecting plate 12, the pressing plate 16, the heat fusion structure 6, the film overlapping guide structure 3, and the first tube pressing structure 14 are all located below the second tube pressing structure 15. At this time, the bottom surface of the tube 9 faces upward and the front surface of the tube 9 faces downward.

[0060] In addition to the above embodiments, the pipe 9 can also be a round pipe, such as Figure 10 As shown, to avoid interference between the second roller 31 and the third roller 32, the axes of the second roller 31 and the third roller 32 are not arranged on the same plane, and the contact portion between their wheel surfaces and the film 10 is parallel to the surface of the tube 9 at that location. In addition to being located on the upper or lower side of the tube 9, the film overlapping portion 101 can also be located on the front or rear side of the tube 9.

[0061] Example 3

[0062] like Figure 11 As shown, the difference from Examples 1 and 2 is that in the tube wrapping head of this embodiment, the film stacking guide structure 3 further includes a baffle 35, which is composed of two pieces. The two baffles 35 are respectively located in front of the second roller 31 and the third roller 32 along the conveying direction of the tube 9, and the lower edge of the baffle 35 is slightly tilted backward, as shown in FIG. Figure 11As shown, the lower edge of the baffle 35 corresponds to the film overlap 101 on the tube 9. Specifically, the two baffles 35 are connected to the second roller frames 36 of the second roller 31 and the third roller 32, respectively. The film 10 on the tube 9 first passes over the baffle 35, where its lower edge presses the film 10 downward. The film 10 then passes over the second roller 31 or the third roller 32, overlapping the film 10 to form the film overlap 101. The baffle 35 prevents the pressing rollers from pressing the film 10 insufficiently.

[0063] The present invention has been described above in conjunction with the best embodiments, but the present invention is not limited to the embodiments disclosed above, but should cover various modifications and equivalent combinations based on the essence of the present invention.

Claims

1. A pipe coating method, characterized in that: The film (10) is allowed to enter the film guide groove (1), and the pipe (9) is allowed to pass through the film guide groove (1) synchronously, so that the film (10) is located on the bottom surface of the pipe (9), and at the same time, the two side parts of the film (10) are respectively located on the two sides of the pipe (9); at the rear side of the film guide groove (1), the film guide tensioning structure (2) is used to tighten the film (10) and cover the two side walls of the pipe (9), and then the film overlapping guide structure (3) is used to tighten the two edge sections of the film (10) on the front side of the pipe (9) to form a film overlapping part (101), and then the film overlapping part (101) is heat-fused to complete the pipe film wrapping; The film guide tensioning structure (2) comprises at least one set of first rollers (21) symmetrically arranged on both sides of the tube, and the film (10) is pressed against the side wall of the tube (9) by the first rollers (21). The rolling tangent direction of the first rollers (21) on the film (10) forms an acute angle α with the conveying direction of the tube (9), so that when the first rollers (21) rotate, a tensioning force is formed on the film (10) toward the side where the front of the tube (9) is located; The film stacking guide structure (3) presses the two edge sections of the film (10) against the front surface of the tube (9) through the second roller (31) and the third roller (32), respectively. The rolling tangent direction of the second roller (31) and the third roller (32) on the film (10) forms an acute angle β with the conveying direction of the tube (9), so that the second roller (31) and the third roller (32) can form a tensioning force on the film (10) toward the middle of the front surface of the tube (9) when they rotate.

2. A pipe coating method according to claim 1, characterized in that: There is elastic contact between the first roller (21) and the film (10); and the pressure exerted by the first roller (21) on the pipe (9) is adjustable.

3. A pipe coating method according to claim 1, characterized in that: The spacing between the group of first rollers (21) is adjustable, and the size of the acute angle α is adjustable.

4. A pipe coating method according to claim 1, characterized in that: The first roller (21) is linked to a first active driving mechanism.

5. A pipe coating method according to claim 1, characterized in that: When the second roller (31) and the third roller (32) respectively contact the two edge sections of the film (10), they avoid the film overlapping portion (101); the lateral spacing between the second roller (31) and the third roller (32) is adjustable; and the size of the acute angle β is adjustable.

6. A pipe coating method according to claim 1, characterized in that: The second roller (31) and the third roller (32) are in elastic contact with the film (10); and the pressure exerted by the second roller (31) and the third roller (32) on the pipe (9) is adjustable.

7. A pipe coating method according to claim 1, characterized in that: The second roller (31) is linked to a second active drive mechanism, and the third roller (32) is linked to a third active drive mechanism.

8. A pipe coating method according to claim 1, characterized in that: The thermal fusion is one of laser welding and ultrasonic welding.

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