Film stripping method

Abstract

To remove a coating efficiently and completely from an inner face of a lining pipe.SOLUTION: A coating peeling device 11 includes a ring-shaped peeling blade 21 insertable between a coating of a cylindrical member 1 which includes the coating 3 on an inner face of a pipe body 2 and a pipe body and advanceable in an axial direction of the cylindrical member, where the coating is peeled off from the pipe body by advancing the peeling blade in the axial direction while being inserted between the pipe body and the coating. The peeling blade is C-shaped and includes a slit extending in the axial direction and elastically deformable so as to vary the diameter.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention , covered The present invention relates to a film peeling method, and more particularly to a technique for peeling off a coating such as resin or rubber formed on the inner surface of a tubular member such as a lined steel pipe. [Background technology]

[0002] 2. Description of the Related Art Lined pipes, which are made by applying a coating of polyolefins such as polyethylene and polypropylene, or resin materials such as polyvinyl chloride, or rubber materials to the inner surface of metal pipes such as steel pipes, are used in a variety of industrial fields.

[0003] For example, polyethylene powder lined steel pipe (PEL), in which polyethylene powder is heat-sealed to the surface of a steel pipe to form a coating, has excellent features such as the chemical and physical stability of the coating and ease of processing, and is therefore used as a corrosion-resistant steel pipe for transporting various fluids.

[0004] On the other hand, when such a lined pipe is to be discarded, when the coating resin or metal pipe is to be reused as resources, or when the lined pipe is to be regenerated by replacing the coating, it is necessary to peel off the coating formed on the pipe surface and separate the coating from the pipe body.

[0005] For this reason, for example, the following patent documents have been proposed to strip the coating from the lining pipe. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 6-167195 [Patent Document 2] JP 2000-210937 A [Patent Document 3] JP 2001-191330 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, none of the conventional methods for removing the coating are necessarily satisfactory in terms of removal efficiency and workability, and there is room for further improvement.

[0008] Specifically, the invention described in Patent Document 1 involves cutting the coating (lining layer) with numerous scraper blades equipped with cutting blades at the tips, and then scraping off the coating in a strip shape with a scraper having ordinary scraping claws. This requires a two-stage processing process to remove the coating, which has problems in terms of peeling efficiency.

[0009] In addition, because the coating is cut into small pieces by numerous cutting blades, depending on the structure of the scraper used in the next process, it is possible that the coating inside the tube may not be completely removed, and finely cut pieces of the coating may remain on the inner surface of the tube.

[0010] On the other hand, the inventions described in Patent Documents 2 and 3 basically involve gripping the edge of the coating and peeling it off (pulling it off). This means that the coating may tear off during the process, and the coating may have to be re-gripped several times. In particular, the tube may be heated to make it easier to peel off the coating, but while a heated coating is more likely to separate from the tube surface, the coating that has become softened by heating is more likely to tear off when pulled.

[0011] If the coating (resin) is to be disposed of without being reused, it is possible to heat the lining pipe and incinerate the coating, but this is not an environmentally useful method because exhaust gases containing harmful substances may be produced when the coating is burned.

[0012] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is therefore to efficiently and more completely remove coatings from the inside surface of lining pipes. [Means for solving the problem]

[0013] In order to solve the above problems and achieve the object, the coating peeling device of the present invention has a ring-shaped peeling blade that can be inserted between the coating of a tubular member having a coating on the inner surface of the tube body and the tube body and can advance in the axial direction of the tubular member, and peels the coating from the tube body by inserting the peeling blade between the tube body and the coating and advancing it in the axial direction of the tube, and the peeling blade has a C-shape with a slit extending in the axial direction of the tube, and is elastically deformable so that its diameter can change.

[0014] The coating peeling device of the present invention (hereinafter sometimes simply referred to as the "peeling device") has a ring-shaped peeling blade suitable for peeling off a coating provided on the inner surface of a tube body, and is particularly characterized in that the peeling blade has a slit extending in the axial direction of the tube (which is also the axial direction of the ring-shaped peeling blade), and by having this slit, the peeling blade can be elastically deformed so that its diameter changes, in other words, so that the width of the slit changes.

[0015] Therefore, by preparing a stripping blade having an outer diameter slightly larger than the inner diameter of the tube body of the tubular member to be stripped (larger than the inner diameter of the tube body and capable of being elastically deformed to insert into the tubular member), and elastically deforming this stripping blade to reduce its diameter (to reduce the width of the slit), and inserting it between the inner peripheral surface of the tube body and the coating while pushing it into the tubular member, it can be brought into close contact with the inner peripheral surface of the tube body. Then, by moving the stripping blade in the axial direction of the tube, the elastic force of the stripping blade maintains this close contact state (state in which the stripping blade is pressed against the inner peripheral surface of the tube body), making it possible to more reliably strip the coating from the inner peripheral surface of the tube body by scraping it off.

[0016] The end (starting end) of the tubular member where peeling of the coating begins may have the coating peeled off in advance with another scraper or the like so that the peeling blade can be inserted between the tube body and the coating. Also, for the end (terminal end) on the side where peeling of the coating will finish, the coating may be peeled off in advance with another scraper or the like in the same manner as for the starting end (it may be peeled off last, but since the coating is likely to remain on the terminal end, it is preferable to peel it off first together with the starting end).

[0017] The advantage of the stripping device of the present invention equipped with the above-mentioned stripping blade is that the inner diameter of the lining pipe is necessarily subject to manufacturing tolerances, and therefore the inner diameter of the pipe body is not uniform and varies from one to another. For this reason, if a stripping blade that is simply ring-shaped and has no slits is equipped, a gap is likely to form between the stripping blade and the inner peripheral surface of the pipe body, and if the stripping blade is to be brought into close contact with the inner peripheral surface of the pipe body, the stripping blade may not be able to enter the pipe. In contrast, the stripping blade of the present invention, which is equipped with slits and has elasticity, can be brought into closer contact with the inner peripheral surface of the pipe more reliably.

[0018] Furthermore, as described later, it is preferable to heat the lining pipe before peeling (to reduce the adhesive strength of the coating and make it easier to peel), but when heated, the diameter of the pipe body increases due to thermal expansion, making it difficult to closely contact the inner circumferential surface of the pipe with a simple ring-shaped peeling blade. In contrast, the peeling blade of the present invention expands (the diameter of the peeling blade increases) to follow the thermally expanded pipe body, so it can be well suited to such aspects in which a pre-heating process is performed.

[0019] The stripping blade preferably has a single-edged blade portion at its front end, which has a wedge-shaped cross section with a pointed tip (front end) and is provided with a tapered surface only on the inner peripheral surface side, because such a single-edged structure allows the entire blade (up to the tip of the blade) to be in close contact with the inner peripheral surface of the pipe body, making it possible to strip the coating more effectively.

[0020] The stripping blade may also be provided with a blade not only on the front side but also on the rear side. That is, the rear end of the stripping blade may further be provided with a single-edged blade portion having a wedge-shaped cross section with a pointed tip (rear end) and a tapered surface formed only on the inner peripheral surface side to provide a blade. With this structure, even if the stripping blade is removed, it can be attached to the stripping device and set on the lining pipe without worrying about the direction of the blade (front and rear direction). Also, even if the coating is firmly attached to the pipe body and the coating cannot be completely peeled off by moving the stripping blade forward once (one way), leaving behind residue, by pulling the stripping blade backward (without removing the stripping blade from the lining pipe), it becomes possible to completely remove the residue with the blade portion provided on the rear side.

[0021] The peeling device may further include a support means for supporting the peeling blade inside the tubular member so as to be movable in the axial direction of the tube.

[0022] The support means may have a feed mechanism for moving the stripping blade in the tube axial direction. The feed mechanism may include a feed screw that extends inside the tube body in the tube axial direction and has a male thread on its outer circumferential surface, and a slide member that has a female thread that screws into the male thread and moves in the tube axial direction as the feed screw rotates, and the stripping blade may be fixed to the slide member.

[0023] The feed mechanism may include a handle provided at one end of the feed screw for rotating the feed screw. The feed mechanism may include a rotary drive device for rotating the feed screw. The rotary drive device is a device that generates a rotary drive force, such as an electric motor or a hydraulic motor. The feed mechanism may include a linear drive device for moving the stripping blade in the axial direction of the pipe. The linear drive device is a device that generates a linear drive force, such as a hydraulic cylinder or a pneumatic cylinder. In the above description, the feed mechanism is a feed screw, but the feed mechanism is not limited to this, and it is also possible to use a chain or wire that can pull the stripping blade in the longitudinal direction of the pipe.

[0024] The peeling device according to the present invention may further include a fixing means for fixing the peeling device to flanges provided at both ends of the tubular member. In this case, the fixing means may have, for example, a support member that can be fixed to the outside of the flange provided at one end of the tubular member at a distance from the flange, and the feed screw is rotatably supported by the support member.

[0025] In addition, when the flange portion provided at one end of the tubular member is defined as the "first flange portion" and the support member fixable to the outside of the flange portion provided at one end of the tubular member is defined as the "first support member," the fixing means may further include a second support member fixable to the outside of a second flange portion provided at the other end of the tubular member at a distance from the second flange portion, and the feed screw may be rotatably supported so as to span between the first support member and the second support member. When the lining pipe to be stripped is short, the stripping operation can be performed with one support member supporting the stripping device and fixed to only one (one) flange portion, and the present invention includes such a device configuration, but when the lining pipe is long, it is more stable to support (fix) the stripping device by fixing it to the flange portions at both ends of the pipe with two support members (first support member and second support member).

[0026] The peeling device of the present invention may further include one or more axial cutting blades that are supported in front of the peeling blade and move together with the peeling blade in the axial direction to cut the coating in the axial direction. With such an apparatus structure, the coating is cut and divided in the axial direction before peeling by the peeling blade, so that the coating is more easily peeled off than when a continuous coating is peeled off over the entire inner circumferential surface of the tubular member, and the coating can be peeled off more reliably.

[0027] The coating stripping method according to the present invention has the same features as the coating stripping apparatus.

[0028] Specifically, the coating peeling method is a coating peeling method in which a ring-shaped peeling blade is inserted between the coating of a tubular member having a coating on the inner surface of the tube body and the tube body, and the peeling blade is advanced in the axial direction of the tubular member to peel off the coating from the tube body, the peeling blade having a C-shaped shape with a slit extending in the axial direction of the tube, which allows it to elastically deform so that its diameter changes, and has an outer diameter larger than the inner diameter of the tube body of the tubular member to be peeled off, and the coating peeling method includes a peeling blade insertion step in which the peeling blade is elastically deformed to reduce its diameter and inserted between the tube body and the coating, and a peeling blade advancement step in which the peeling blade inserted between the tube body and the coating in the peeling blade insertion step is advanced in the axial direction of the tube.

[0029] In this peeling method, too, for the same reasons as in the peeling device, it is preferable to use a peeling blade having the single-edged structure described above in relation to the peeling device.

[0030] In addition, either or both of a circumferential cutting step of cutting the coating in the circumferential direction of the tubular member and an axial cutting step of cutting the coating in the axial direction of the tubular member may be performed before the peeling blade advancing step, in order to make the coating easier to peel off by dividing it.

[0031] In the peeling blade advancement step, an axial cutting process for cutting the coating in the axial direction of the tubular member may be performed simultaneously with the advancement of the peeling blade. In this case, the axial cutting process is performed by cutting the coating portion forward of the peeling blade with an axial cutting blade disposed forward of the peeling blade and advancing together with the peeling blade.

[0032] Furthermore, it is preferable to carry out a heating step of heating the tubular member before peeling off the coating (before the peeling blade advancing step) in order to reduce the adhesive strength of the coating to the tube body and make it easier to peel off.

[0033] In this case, the preferred heating method is induction heating of the tube body. Induction heating allows the inner peripheral surface of the tube body (the boundary surface with the coating) to be heated efficiently and uniformly, making it possible to peel off the coating more smoothly. However, the present invention does not exclude other heating methods, such as using a gas burner. Effect of the Invention

[0034] According to the present invention, it is possible to efficiently and more completely remove the coating from the inner surface of the lining pipe.

[0035] Other objects, features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings. In the drawings, the same reference numerals indicate the same or corresponding parts. [Brief description of the drawings]

[0036] [Figure 1] FIG. 1 is a perspective view showing a coating removing device according to a first embodiment of the present invention, with the left half cut away along the central axis. [Diagram 2] FIG. 2 is an enlarged perspective view of the rear end portion of FIG. [Diagram 3] FIG. 3 is an enlarged longitudinal sectional view of the rear end portion of FIG. [Figure 4] FIG. 4 is an enlarged perspective view of a peeling blade provided in the coating peeling device of the first embodiment. [Diagram 5] FIG. 5 is a vertical cross-sectional view (as viewed from the front side / cross-section A2-A2 in FIG. 6) showing the relationship between the peeling blade and a clamping plate (rear clamping plate) supporting the peeling blade provided in the coating peeling device of the first embodiment. [Figure 6] FIG. 6 is a vertical cross-sectional view (as viewed from the left side / cross-section A1-A1 in FIG. 5) showing the relationship between the peeling blade provided in the coating peeling device of the first embodiment and the clamping plates (front clamping plate and rear clamping plate) that support it. [Figure 7] FIG. 7 is a cross-sectional view (as viewed from the left side) showing the relationship between the peeling blade and a tubular member provided in the coating peeling device of the first embodiment. [Figure 8] FIG. 8 is a cross-sectional view similar to FIG. 7 showing the relationship between the peeling blade and a tubular member provided in the coating peeling device of the first embodiment (in a state where the peeling blade is inserted between the tube body and the coating). [Figure 9] FIG. 9 is a perspective view showing an example of a circumferential cutting device for circumferentially cutting a coating using the coating peeling method of the present invention (with the device body inserted into a tubular member) (the left halves of the tube body and coating are cut away so that the inside of the tubular member can be seen). [Figure 10] FIG. 10 is a cross-sectional view (viewed from the left side / only the peeling blade is shown) similar to FIG. 7, showing a modified example of the peeling blade provided in the coating peeling device of the first embodiment. [Figure 11] FIG. 11 is an enlarged perspective view similar to FIG. 2 showing a coating stripping apparatus according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] [First embodiment] 1 to 8, a coating peeling device 11 according to a first embodiment of the present invention comprises an apparatus main body 12 equipped with a peeling blade 21 for peeling off an inner coating 3 from a lining pipe (tubular member) 1, a drive unit 13 for moving the apparatus main body 12 in the pipe axial direction (the pipe axis is indicated by reference symbol 1a in FIG. 3) inside the lining pipe 1, and an apparatus fixing unit 14 for fixing the apparatus main body 12 and the drive unit 13 to the lining pipe 1. Each figure shows mutually orthogonal two-dimensional or three-dimensional coordinates representing the front-rear, left-right, and up-down directions, and the following description will be based on these directions.

[0038] In addition to the peeling blade 21, the device main body 12 has a slide member 24 that has a female thread 25 that screws with a male thread 31a formed on the outer circumferential surface of a feed screw shaft (hereinafter sometimes simply referred to as "shaft") 31 described below and moves in the tube axial direction upon rotation of the shaft 31, and a pair of clamping plates 26, 27 that are fixed to the slide member 24 and clamp the peeling blade 21 so as to be slidably deformable. The clamping plates 26, 27 consist of a front clamping plate 26 and a rear clamping plate 27 that are arranged to face each other at a fixed interval in the front-rear direction.

[0039] The peeling blade 21 is composed of a ring-shaped blade body 22 and a plurality of (four in this embodiment) support legs 23 that stand from the inner peripheral surface of the blade body 22 toward the center of the blade body 22. The blade body 22 has a blade formed on its front edge. More specifically, the front edge of the blade body 22 has a tapered surface 22a inclined only on the inner peripheral surface (the outer peripheral surface is a cylindrical surface parallel to the axis of the blade body 22) so that the thickness becomes thinner toward the front, and the tip (front end) is sharpened to form a single-edged blade (single-edged blade portion) 22a. The reason for using such a single-edged shape rather than a double-edged shape is to make the entire blade, including the tip (front end), adhere closely to the inner peripheral surface of the pipe body 2 without any gaps, and to more reliably peel off the coating 3.

[0040] The blade body 22 is also formed with a slit 22b (see Figs. 4 and 5) extending in the axial direction of the blade body 22 (which coincides with the pipe axis direction of the lining pipe 1). This is to allow the blade body 22 to be elastically deformed so that the diameter changes, or in other words, the width of the slit 22b changes. Note that in Fig. 5, the state in which the blade body 22 with a slit width W1 is elastically deformed so that the diameter becomes smaller and the slit width becomes W2 (W1>W2) is shown by a two-dot chain line.

[0041] In addition, the outer diameter of the blade body portion 22 is larger than the inner diameter of the pipe body 2 of the lined pipe 1 that is the target of coating peeling, and is sized so that the blade body portion 22 can be elastically deformed in the radial direction so as to reduce its diameter and be inserted into the lined pipe 1.

[0042] Therefore, when the peeling blade 21 is inserted into the lining pipe 1 while elastically deforming the blade body portion 22, the blade body portion 22 adheres closely to the inner surface of the pipe body 2 without any gap being generated between the blade body portion 22 and the lining pipe 1 (pipe body 2), so that the blade body portion 22 is pressed against the inner surface of the pipe body 2 by the elastic force of the blade body portion 22.

[0043] On the other hand, in order to support the stripping blade 21 in such an elastically deformable manner, the clamping plates 26, 27 have the following structure: The front clamping plate 26 has its rear surface which is flat and is simply brought into slidable contact with the support legs 23 of the stripping blade 21, more specifically, the front surfaces of the tips of the support legs 23 (the ends closer to the center of the blade body 22), while the rear clamping plate 27 has fitting grooves 28 formed in its front surface which correspond to the support legs 23 of the stripping blade 21, and the rear portions of the tips of the support legs 23 are housed in the corresponding fitting grooves 28.

[0044] Here, each fitting groove 28 is wider than the support leg 23, and a gap is formed between each fitting groove 28 and both side surfaces of the support leg 23. Therefore, each support leg 23 is movable in the circumferential direction of the blade body 22 (see arrow X1 in FIG. 5). Furthermore, each fitting groove 28 extends to a position closer to the center than the support leg 23 in terms of its radial length, and a gap is formed between the tip of the support leg 23 and the tip of the fitting groove 28 (the end closer to the center). Therefore, each support leg 23 is movable in the radial direction of the blade body 22 (can move toward the center of the blade body 22) (see arrow Y1 in FIG. 5).

[0045] In this way, the peeling blade 21 (support leg 23) is clamped by both clamping plates 26, 27 so that each support leg 23 can move (displace) circumferentially and radially of the blade main body 22 within each corresponding fitting groove 28, and therefore the peeling blade 21 can elastically deform without falling off from the device main body 12.

[0046] The device fixing portion 14 has a front support plate (first support member) 42 that can be fixed to the front flange portion (first flange portion) 2b of the lining pipe 1, and a rear support plate (second support member) 41 that can be fixed to the rear flange portion (second flange portion) 2a of the lining pipe 1. The front support plate 42 is fixed in front of the front flange portion 2b at a fixed distance using fastening means (bolts B and nuts N). The rear support plate 41 is fixed to the rear of the rear flange portion 2a at a fixed distance using fastening means (spacer tube S, bolts B, and nuts N interposed between the rear flange portion 2a and the rear support plate 41).

[0047] Although the drawings (Figs. 1 to 3) only show one fastening means for fixing each of the support plates 41, 42 to the flange portions 2a, 2b (one location in the circumferential direction of each of the support plates 41, 42), the fastening means is provided in multiple locations (preferably three or more locations) so as to be evenly spaced in the circumferential direction, and each of the support plates 41, 42 is fixed to each of the flange portions 2a, 2b by these multiple fastening means.

[0048] The drive unit 13 has a feed screw shaft 31 that is installed so as to penetrate the inside of the lining pipe 1 along the central axis 1a of the lining pipe 1, and a handle 32 that is provided at the rear end of the shaft for rotating the shaft 31. The shaft 31 is rotatably supported by both support plates 41, 42 so as to span between the front support plate 42 and the rear support plate 41 of the device fixing unit 14, and the shaft 31 rotates when the handle 32 is turned.

[0049] An external thread 31a is formed on the outer peripheral surface of the shaft 31 over almost the entire length of the portion that is placed inside the lining pipe, and the rotational motion of the shaft 31a is converted into linear motion of the slide member 24 (peeling blade 21) by this external thread 31a and the internal thread 25 of the slide member 24 that screws into the external thread 31a.

[0050] In this embodiment, the feed screw 31 is manually operated by turning the handle 32, but as already mentioned, the feed screw 31 may be driven by a rotary drive device such as an electric motor (motor) or a hydraulic motor. Also, in this embodiment, a feed mechanism (the feed screw 31 and the slide member 24) that converts rotary motion into linear motion is provided, but instead, a device that generates a linear (linear motion) drive force such as a hydraulic cylinder or a pneumatic cylinder may be provided to directly propel the stripping blade 21 in the tube axial direction.

[0051] [Removal work] In order to peel the coating 3 from the lining pipe 1 using the peeling device according to this embodiment, the following procedure may be performed.

[0052] First, the lined pipe 1 is heated to reduce the adhesive strength of the coating 3, and the coating 3a (see FIG. 7) at the rear end of the lined pipe 1 where peeling begins is peeled off with a scraper or the like prepared separately. At this time, the coating 3 at the front end including the surface of the front flange portion 2b may also be peeled off with a scraper or the like. The heating of the lined pipe 1 is preferably performed by high-frequency induction heating, which can uniformly and efficiently heat the surface of the pipe body 2 (the inner peripheral surface of the pipe body 2, which is the boundary between the pipe body 2 and the coating 3), but it is also possible to heat it by other methods (for example, a gas burner).

[0053] Next, the stripping device 11 is installed on the lining pipe 1 by fixing the front support plate 42 to the front flange portion 2b and the rear support plate 41 to the rear flange portion 2a. Note that the support plate (for example, the front support plate 42) is detachable from the feed screw shaft 31, and when installing the stripping device 11 on the lining pipe 1, the front support plate 42 is removed, the shaft 31 is inserted into the lining pipe 1, and then the front support plate 42 is attached to the front end of the shaft 31.

[0054] After the peeling device 11 is attached to the lining pipe 1, the handle 32 is turned to move the peeling blade 21 forward and enter the lining pipe 1 from the rear opening. At this time, the peeling blade 21 is fitted into the lining pipe 1 while applying force to the peeling blade 21 to deform it so that its diameter becomes smaller (so that the width of the slit 22b becomes narrower).

[0055] Then, by turning the handle 32 again to advance the peeling blade 21 forward within the pipe, the tip (leading edge) of the blade body 22, which is in close contact with the inner circumferential surface of the pipe body 2, is inserted like a wedge into the boundary between the pipe body 2 and the coating 3 (see FIG. 8), and as the peeling blade 21 advances, the coating 3 is lifted along the tapered surface 22a of the tip of the peeling blade, and the coating 3 is continuously peeled off one after another from the inner circumferential surface of the pipe body 2. By advancing the peeling blade 21 to the front end of the lined pipe 1 in this manner, the coating 3 provided inside the pipe can be peeled off.

[0056] In the above peeling operation, the coating 3 may be previously cut and divided in the circumferential direction of the lining pipe 1. This is because dividing the coating 3 into several coating pieces makes it easier to peel off the coating 3.

[0057] Figure 9 shows a circumferential cutting device 51 for performing such cutting. As shown in the figure, this cutting device 51 is equipped with a device main body 52 that can be inserted into the inside of the lining pipe 1, and a support rod 53 that supports the device main body 52 within the lining pipe 1 and enables the device main body 52 to rotate in the circumferential direction.

[0058] The device main body 52 is equipped with a rotary blade (circumferential cutting blade) 54, which is a disk-shaped metal member with a blade formed on the periphery, and by rotating the device main body 52 inside the pipe by pressing the rotary blade 54 against the inner circumferential surface (surface of the coating 3) of the lining pipe 1 while rotating the support rod 53 (see symbol R1 in Fig. 9), the rotary blade 54 rolls in the circumferential direction, thereby making it possible to cut the coating 3 in the circumferential direction. By performing this operation at multiple points along the length of the lining pipe 1, the coating can be divided into multiple pieces.

[0059] Furthermore, the stripping blade may have a blade not only on the front side but also on the rear side. More specifically, as shown in FIG. 10, the stripping blade 29 has not only the front blade portion 22a but also a single-edged blade portion 22c on the rear side, which has a wedge-shaped cross-sectional shape with a pointed tip (rear end) and is provided with a blade by forming a tapered surface 22c only on the inner peripheral surface side. With such a stripping blade 29, as described above, even when the stripping blade 29 is removed, the stripping blade 29 can be attached to the stripping device 11 and set on the lining pipe 1 without worrying about the direction of the blade (front and rear direction). Also, even if the coating 3 is firmly attached to the pipe body 2 and the coating 3 cannot be completely peeled off by a single (one-way) forward movement of the stripping blade 29, leaving residue, by rotating the handle 32 in the reverse direction to pull the stripping blade 29 backward (without removing the stripping blade 29 from the lining pipe 1), it becomes possible to remove all the residue with the blade portion 22c provided on the rear side.

[0060] Second Embodiment 11 shows a coating peeling device according to a second embodiment of the present invention. As shown in this figure, the peeling device 61 according to the second embodiment includes, in addition to the components of the peeling device 11 according to the first embodiment, an axial cutting blade 62 for cutting the coating 3 in the axial direction of the lined pipe 1.

[0061] That is, the peeling device 61 is equipped with an apparatus main body 12 (clamping plates 26, 27 and slide member 24) including a peeling blade 21 for peeling off the inner coating 3 of the lined pipe 1, similar to the apparatus 11 of the first embodiment, a drive unit 13 (feed screw shaft 31 and handle 32) for moving the apparatus main body 12 in the pipe axial direction within the lined pipe 1, an apparatus fixing unit 14 (rear support plate 41 / front support plate not shown) for fixing the apparatus main body 12 and the drive unit 13 to the lined pipe 1, as well as an axial cutting blade 62 fixed to the apparatus main body 12.

[0062] The axial cutting blade 62 is a rotary blade that rolls on the inner circumferential surface (coating 3) of the lined pipe 1 in the pipe axial direction as the device body 12 advances, and is fixed to the device body 12 so as to be located in front of the peeling blade 21. In this embodiment, a total of two blades are provided, one above and one below, so that the coating 3 is divided into two in the pipe axial direction by the cutting blade 62. Each axial cutting blade 62 is a rotary blade having a blade formed on the periphery of a disk-shaped metal member, similar to the rotary blade 54 provided in the circumferential cutting device 51, and can cut the coating 3 by rolling on the inner circumferential surface of the lined pipe 1.

[0063] In addition, it is preferable that each axial cutting blade 62 is fixed to the device main body 12 via an elastic member (e.g., a coil spring or a leaf spring) so as to more reliably cut the coating 3, and that each cutting blade 62 is pressed against the inner surface of the lining pipe 1 (the surface of the coating 3) when the device main body 12 is inserted into the lining pipe 1.

[0064] In this embodiment, two axial cutting blades 62 are provided so that the coating 3 can be divided into two (two pieces) in the tube axial direction, but the number of the cutting blades 62 may be one, or it is possible to provide three or more cutting blades 62 so that the coating can be divided into three or more pieces. When three or more cutting blades 62 are provided, for example, the cutting blades 62 may be provided in the device main body 12 so as to be radially arranged around the tube axis 1a.

[0065] According to the stripping device 61 of this embodiment, the coating 3 can be divided in the pipe axial direction by the axial cutting blade 62 while being stripped by the stripping blade 21. When using the stripping device 61 of this embodiment, the coating 3 may also be cut in the circumferential direction in advance, as described in the first embodiment. Furthermore, it is preferable to heat the lining pipe 1 to weaken the adhesive strength of the coating 3 prior to the stripping operation.

[0066] Although the embodiments of the present invention have been described above, the present invention is not limited to these, and it will be apparent to those skilled in the art that various modifications can be made within the scope of the claims.

[0067] For example, in the above embodiment, the coating peeling device 11, 61 is fixed directly to the lining pipe 1 to be peeled, but since it is only necessary to prevent the relative positional deviation between the coating peeling device 11, 61 (peeling blade 21) and the lining pipe 1, the coating peeling device 11, 61 can be indirectly fixed to the lining pipe 1, for example, by fixing the coating peeling device 11, 61 and the lining pipe 1 (separately) to a workbench, and the peeling operation can be performed in the same way. In particular, with such an indirect fixing method, the peeling operation of the lining pipe not having the flange parts 2a, 2b can be performed without any problem. [Explanation of symbols]

[0068] 1 Lining pipe (tubular member) 1a Tube shaft 2. Tube body 2a Rear flange portion (second flange portion) 2b Front flange part (first flange part) 3 Coating 3a Coating of rear end of lining pipe 11,61 Film stripping device 12 Device main body 13 Drive unit 14 Device fixing part 21,29 Peeling blade 22 Blade body 22a, 22c Tapered surface (single-edged blade portion) 22b Slit 23 Support legs 24 Slide member 25 Female thread 26 Front clamping plate 27 Rear clamp plate 28 Fitting groove 31 Lead screw shaft 31a Male thread 32 Handle 41 Rear support plate (second support member) 42 Front support plate (first support member) 51 Circumferential cutting device 52 Device main body 53 Support Rod 54 Rotary blade (circumferential cutting blade) 62 Rotary blade (axial cutting blade) B Bolt N Nut S Spacer tube

Claims

1. A film peeling method for peeling a film from a tube body of a tubular member provided with a film on the inner surface of the tube body by inserting a ring-shaped peeling blade between the film and the tube body and advancing the peeling blade in the tube axis direction of the tubular member, wherein the peeling blade has a C-shaped shape with a slit extending in the tube axis direction, is elastically deformable so that its diameter changes, and has an outer diameter larger than the inner diameter of the tube body of the tubular member to be peeled, the film peeling method comprising: a peeling blade insertion step of elastically deforming the peeling blade so that its diameter becomes smaller and inserting it between the tube body and the film; a peeling blade advancing step of advancing the peeling blade inserted between the tube body and the film in the tube axis direction and characterized in that it includes the above.

2. The peeling blade has a wedge-shaped cross-sectional shape with a sharp front end in the advancing direction during peeling, and is a single-edge blade with a taper surface formed only on the inner peripheral surface side to form a blade The film peeling method according to Claim 1.

3. Before the peeling blade advancing step, it further includes a circumferential cutting step of cutting the film in the circumferential direction of the tubular member The film peeling method according to Claim 1 or 2.

4. Before the peeling blade advancing step, it further includes an axial cutting step of cutting the film in the tube axis direction of the tubular member The film peeling method according to any one of Claims 1 to 3.

5. In the peeling blade advancing step, an axial cutting process of cutting the film in the tube axis direction of the tubular member is performed simultaneously with the advancement of the peeling blade, and the axial cutting process cuts a film portion in front of the peeling portion by the peeling blade with an axial cutting blade disposed in front of the peeling blade and advancing together with the peeling blade The film peeling method according to any one of Claims 1 to 3.

6. Before the peeling blade advancing step, it further includes a heating step of heating the tubular member The film peeling method according to any one of Claims 1 to 5.

7. The heating step is performed by induction heating the tube body The film peeling method according to Claim 6.

Images