Coating peeling method, coating peeling tube manufacturing method, and coating peeling device

Abstract

To peel and remove a coating film from a lining pipe having a flange with good efficiency.SOLUTION: A coating film peeling apparatus 11 for peeling a coating film from a lining pipe 1 having a flange 3 at an end part of a pipe body 2 as well as having coating films 4, 5 on at least a pipe body inner peripheral surface and a flange surface is assembled with: a rotation apparatus for rotation of the lining pipe about a pipe axis; an induction heating coil 12 capable of heating the pipe body end part and the flange simultaneously; and a notch apparatus 21 for giving a notch to the coating film at the end part of the pipe body in a manner that the coating film at the pipe body end part is cut in the circumferential direction by rotation of the lining pipe by the rotation apparatus. The induction heating coil has a pipe body heating coil part 13 arranged so as to be opposed to an inner peripheral surface of the pipe body end part and capable of heating the pipe body end part and a flange heating coil part 14 arranged so as to be opposed to the flange surface and capable of heating the flange.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a coating stripping method, a coating stripping pipe manufacturing method, and a coating stripping device, and in particular to a technology for stripping coatings such as resin or rubber formed on the inner circumferential surface and flange surface of a tubular member such as a lined steel pipe with a flange at the pipe end. [Background technology]

[0002] Lining pipes, which are made by applying a coating of polyolefins such as polyethylene and polypropylene, or resin materials such as vinyl 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), which is made by heat-sealing polyethylene powder to the surface of a steel pipe to form a coating, has excellent features such as chemical and physical stability of the coating and ease of processing, and is therefore used as corrosion-resistant steel pipe for transporting various fluids.

[0004] Furthermore, some lined pipes have flanges at the ends. Flanged lined pipes include those in which the coating is formed on the surface of the flange, continuing from the inner circumferential surface of the pipe body, and those in which the coating is formed on the entire pipe, including the back surface of the flange and the outer circumferential surface of the pipe body.

[0005] On the other hand, in order to make effective use of resources, such lined pipes are recycled by replacing the coating when it deteriorates and reproducing (remanufacturing) the lined pipe. In this case, the coating must be peeled off from the lined pipe to separate the metal pipe from the coating. Furthermore, when disposing of lined pipes, the same process is required to separate the metal and coating.

[0006] Furthermore, the following patent documents disclose inventions for peeling off coatings from lining pipes. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 63-100000 [Patent Document 2] Patent Publication No. 2021-016975 Summary of the Invention [Problem to be solved by the invention]

[0008] Incidentally, all of the conventional proposals for stripping the coating from a lining pipe, including the inventions described in the above patent documents, relate to pipes that do not have flanges, and at present, there has been insufficient research into techniques for stripping the coating formed on the flanges.

[0009] SUMMARY OF THE INVENTION It is therefore an object of the present invention to efficiently remove coating from a lined pipe having a flange. [Means for solving the problem]

[0010] [First invention] In order to solve the above problems and achieve the object, a coating peeling method according to a first invention of the present application is a coating peeling method for peeling a coating from a lining pipe, wherein the lining pipe comprises a pipe body, a flange provided on at least one end of the pipe body, and a coating formed on at least the inner surface of the pipe body and the surface of the flange, and the coating peeling method includes a heating and cutting step which simultaneously carries out a rotation operation of rotating the lining pipe around the pipe axis, a pipe body heating operation of heating one end of the pipe body from the inside of the pipe body, a flange heating operation of heating the flange from the surface side of the flange, and a cutting operation of making an incision in the coating at one end of the pipe body so that the coating at the one end of the pipe body is cut circumferentially as the lining pipe is rotated by the rotation operation.

[0011] The coating removal method according to the first invention of the present application relates to a method for removing a coating from a lined pipe equipped with a flange, in which the lined pipe is rotated around the pipe axis (the central axis of the pipe in the longitudinal direction) while simultaneously heating the pipe body, heating the flange, and cutting the coating, thereby efficiently removing the coating.

[0012] In particular, in the above method, the pipe body heating operation and the flange heating operation are performed using an induction heating coil, and it is preferable that the induction heating coil has a pipe body heating coil portion that can be arranged to face the inner surface of the pipe body, and a flange heating coil portion that can be arranged to face the surface of the flange.

[0013] This is because the coating surface of the pipe body is uniformly heated simultaneously by the pipe body heating coil section positioned opposite the inner surface of the pipe body, and the coating surface of the flange is heated simultaneously by the flange heating coil section positioned opposite the flange surface, thereby peeling off the coating on the end of the pipe body and the coating on the flange surface together.

[0014] Furthermore, the term "facing" here does not necessarily refer to a state in which the two surfaces (the surface formed by the coil and the surface to be heated) are parallel, but rather refers to a state in which the two surfaces face each other. For example, the inner peripheral surface of the pipe body and the pipe body heating coil portion do not necessarily have to have a curved shape that follows the shape of the inner surface of the pipe body, and may also have a flat shape. Note that efficient and uniform heating is facilitated when the surface formed by the coil and the surface to be heated are parallel.

[0015] Furthermore, when flanged lined pipes are used, the lined pipes are connected together by mating the flanges together (so that the coating formed on the flange surface is sandwiched between the overlapping flanges), and the "surface" of the flange refers to this mating surface (the surface on which the coating is formed).

[0016] Furthermore, it is preferable that the pipe body heating coil portion and the flange heating coil portion are formed in a continuous series (continuously) using a continuous conductor (in other words, formed integrally as one continuous coil).

[0017] This simplifies the power supply wiring to the induction heating coil, eliminates the need to individually control the output of the pipe body coil section and the flange heating coil section, and simplifies the control and operation of the induction heating coil.

[0018] It is also preferable that the number of turns of the flange heating coil portion is greater than the number of turns of the pipe main body heating coil portion.

[0019] Generally, the heating efficiency of an induction heating coil is proportional to the square of the number of turns in the coil. Therefore, when currents of the same magnitude and frequency are passed through the coil, the more turns in the coil, the higher the heating efficiency. Furthermore, the thickness of the flange is generally thicker than that of the pipe body, and the thickness of the coating formed on the flange is often thicker than that of the pipe body. Therefore, by increasing the number of turns in the flange heating coil section to that of the pipe body heating coil section, it is possible to effectively remove the end coating of such a flanged lined pipe, i.e., to sufficiently heat the flange section, which is thick and difficult to heat up, and to remove the thick coating formed on the flange together with the coating on the pipe body.

[0020] Furthermore, if the coil has a large number of turns, the area of ​​the coil facing the flange portion can be secured even when heating a pipe whose flange diameter is smaller than the outermost circumference of the flange heating coil portion, making it possible to accommodate pipes of multiple sizes without reducing heating efficiency.

[0021] Furthermore, the pipe body heating operation and the flange heating operation are preferably carried out at a temperature equal to or higher than the temperature at which the coating softens and lower than the temperature at which the coating becomes viscous.

[0022] The reason for performing the heating at a temperature above the softening point of the coating is to make it easier to peel the coating from the adhered surfaces (the inner circumferential surface of the pipe body and the flange surface) and to make it easier to cut the coating by the cutting and rotating operations. The reason for performing the heating at a temperature below the viscous point is to prevent the coating that peels from the adhered surface from sagging and adhering to the induction heating coil, or to prevent the coating from adhering to a cutting blade (described later) when used in the cutting operation, thereby hindering cutting.

[0023] In addition, it is preferable that the cutting point, where the incision is made in the cutting operation, overlaps with the heating range of the pipe body by the pipe body heating coil section in the pipe axial direction of the pipe body.

[0024] This is to more reliably cut the coating on the inner peripheral surface of the pipe body. In the present invention, in order to cut the coating of the pipe body in the circumferential direction, an incision is made in the coating in the incision operation, and this incision point moves in the circumferential direction relative to the inner peripheral surface (coating) of the pipe body as the lining pipe rotates, thereby cutting the coating in the circumferential direction. However, by making the incision point overlap with the heating range by the pipe body heating coil in the pipe axial direction of the pipe body (positioned within the heating range), it becomes possible to reliably cut the heated and softened coating.

[0025] Furthermore, it is preferable that the cutting point be located at a position outside the heating range of the pipe body heating coil in the circumferential direction of the pipe body, in order to avoid interference between the cutting means (e.g., a cutting blade) and the pipe body heating coil (clashing and getting in the way of each other, or the cutting means interfering with heating by the coil).

[0026] The means for performing the incision operation is typically a cutting blade, as in the embodiment described below. That is, the incision operation is performed by pressing the cutting blade against the coating. However, the means is not necessarily limited to a mechanical means such as a cutting blade, and the incision operation can also be performed by other methods, such as irradiating the incision point with laser light.

[0027] Furthermore, the method for manufacturing a coating-stripped pipe according to the first invention of the present application has the same characteristics as the coating stripping method according to the first invention described above, and is a method for manufacturing a coating-stripped pipe (a metal pipe from which the coating has been stripped and removed) that serves as the raw material (raw material) for, for example, regenerating a lined pipe (removing a deteriorated or damaged coating and forming a new coating to produce a regenerated lined pipe).

[0028] Specifically, the method for manufacturing a coated-removed pipe is a method for manufacturing a coated-removed pipe by peeling and removing a coating from a lined pipe, the lined pipe comprising a pipe body, a flange provided on at least one end of the pipe body, and a coating formed on at least the inner peripheral surface of the pipe body and the surface of the flange, and the method includes the following steps: (1) preparing a lining pipe; After the process of preparing the lining pipe, (2a) Rotation of the lining pipe around the pipe axis; (2b) A pipe body heating operation in which one end of the pipe body is heated from the inside of the pipe body; (2c) a flange heating operation in which the flange is heated from the surface side of the flange; and (2d) A cutting operation in which a cut is made in the coating at one end of the pipe body so that the coating at one end of the pipe body is cut in the circumferential direction by rotating the lining pipe by the rotating operation. A heating and cutting process is performed simultaneously. Includes:

[0029] The above manufacturing method may also have the features of the preferred aspects described above for the coating peeling method.

[0030] The coating stripping device according to the first invention of the present application has the same features as the coating stripping method and each aspect according to the first invention.

[0031] Specifically, the coating removal device is a coating removal device that removes a coating from a lining pipe that has a flange at the end of the pipe body and has a coating on at least the inner surface of the pipe body and the surface of the flange, and is equipped with a rotating device that rotates the lining pipe around the pipe axis, an induction heating coil that can heat the end of the pipe body and the flange simultaneously, and a cutting device that makes an incision in the coating on the end of the pipe body so that the coating on the end of the pipe body is cut circumferentially as the lining pipe is rotated by the rotating device, and the induction heating coil has a pipe body heating coil section that is positioned opposite the inner surface of the end of the pipe body and is capable of heating the end of the pipe body, and a flange heating coil section that is positioned opposite the surface of the flange and is capable of heating the flange.

[0032] In the coating peeling device, the pipe body heating coil portion and the flange heating coil portion may be formed in a continuous manner using a continuous conductor.

[0033] In addition, in the coating peeling device, the number of turns of the flange heating coil portion may be greater than the number of turns of the pipe body heating coil portion.

[0034] Furthermore, in the coating peeling device, the incision point, where the incision is made by the incision device, may overlap with the heating range by the pipe body heating coil section in the axial direction of the pipe body (in other words, located within the range from the tip to the base end of the pipe body heating coil section), and may be located outside the heating range by the pipe body heating coil section in the circumferential direction of the pipe body.

[0035] Furthermore, the cutting device has a cutting blade that can make an incision in the coating by pressing it against the coating at the cutting point, and the cutting blade may be positioned so as to overlap with the pipe body heating coil portion in the axial direction of the pipe body (in other words, positioned within the range from the tip to the base end of the pipe body heating coil portion), and to be positioned outside the pipe body heating coil portion in the circumferential direction of the pipe body.

[0036] [Second Invention] The coating removal method according to the second invention of the present application involves heating the pipe body and flange from the side opposite to that of the first invention, i.e., from the outer surface side of the pipe body and from the back surface side of the flange.

[0037] More specifically, the coating removal method of the second invention is a coating removal method for removing a coating from a lined pipe, the lined pipe comprising a pipe body, a flange provided on at least one end of the pipe body, and a coating formed on at least the inner surface of the pipe body and the surface of the flange, and the coating removal method includes a heating and cutting step that simultaneously performs a rotation operation of rotating the lined pipe around the pipe axis, a pipe body heating operation of heating one end of the pipe body from the outside of the pipe body, a flange heating operation of heating the flange from the back side of the flange, and a cutting operation of making an incision in the coating at one end of the pipe body so that the coating at one end of the pipe body is cut circumferentially as the lined pipe is rotated by the rotation operation, and the pipe body heating operation and the flange heating operation are performed using an induction heating coil, and the induction heating coil has a pipe body heating coil portion that can be positioned to face the outer peripheral surface of the pipe body, and a flange heating coil portion that can be positioned to face the back side of the flange.

[0038] The "rear surface" of the flange refers to the surface opposite to the "front surface" of the first invention (the surface on the rear side of the flange). The meaning of "facing" above is the same as that of "facing" explained in the first invention.

[0039] The advantages of the second invention compared to the first invention are as follows.

[0040] When the lining pipe is heated, the resin or rubber that makes up the coating or the adhesive that bonds the coating may decompose, generating gas, which may cause the coating to swell or sag. If this swelling or sagging causes the coating to adhere to the coil, this may have a negative effect on heating. From the perspective of avoiding this, the second invention, in which heating is performed from the outside of the pipe, is advantageous.

[0041] On the other hand, in the second invention, the peeling surface (the inner surface of the pipe and the flange surface) on which the coating is provided is heated by thermal conduction, so in terms of heating efficiency, the first invention, which can heat the metal part close to the object to be peeled (the coating on the inner surface of the pipe body and the flange surface), is more advantageous than the second invention.

[0042] Furthermore, the coating peeling device according to the second invention of the present application has the same features as the coating peeling method according to the second invention.

[0043] Specifically, the coating removal device is a coating removal device that removes a coating from a lining pipe that has a flange at the end of the pipe body and a coating on at least the inner surface of the pipe body and the surface of the flange, and is equipped with a rotating device that rotates the lining pipe around the pipe axis, an induction heating coil that can heat the end of the pipe body and the flange simultaneously, and a cutting device that makes an incision in the coating on the end of the pipe body so that the coating on the end of the pipe body is cut circumferentially as the lining pipe is rotated by the rotating device, and the induction heating coil has a pipe body heating coil section that is positioned opposite the outer peripheral surface of the end of the pipe body and is capable of heating the end of the pipe body, and a flange heating coil section that is positioned opposite the back surface of the flange and is capable of heating the flange.

[0044] In addition, the coating stripping method and coating stripping device according to the second invention can be configured to have the features of each aspect described in the description of the first invention, just like the first invention. [Effects of the Invention]

[0045] According to the present invention, it is possible to efficiently remove coating from a lined pipe equipped with a flange.

[0046] Other objects, features, and advantages of the present invention will become apparent from the following description of the preferred embodiments of the present invention, which is given with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention is not limited to the preferred embodiments, and that various modifications can be made within the scope of the claims. In addition, the same reference numerals in the various drawings indicate the same or equivalent parts. [Brief explanation of the drawings]

[0047] [Figure 1] FIG. 1 is a perspective view showing a coating removing device according to a first embodiment of the present invention (showing the right side (the front side of the figure) cut away together with a lining pipe / cross section taken along the arrow BB in FIG. 5). [Figure 2] FIG. 2 is a side view showing the coating removing device according to the first embodiment (similar to FIG. 1, the right side portion (the front side of the figure) is cut away together with the lining pipe / a cross section taken along the arrow BB in FIG. 5). [Figure 3] FIG. 3 is a plan view showing the coating peeling device according to the first embodiment (similar to FIG. 1, the right side (the front side of the figure) is cut away together with the lining pipe). [Figure 4] FIG. 4 is a perspective view showing an induction heating coil of the coating stripping apparatus according to the first embodiment. [Figure 5] FIG. 5 is a front view (a cross section taken along the line AA in FIG. 2) showing the coating peeling device according to the first embodiment. [Figure 6] FIG. 6 is a perspective view showing a coating peeling device according to a second embodiment of the present invention (the rotating device, cutting device and power supply device are not shown). DETAILED DESCRIPTION OF THE INVENTION

[0048] [First embodiment / coating peeling device] As shown in Figures 1 to 5, the coating removal device 11 according to the first embodiment of the present invention is an apparatus for removing coatings 4, 5 from the end of a flanged lining pipe 1, and includes a rotation device 31 (see Figure 5) for rotating the lining pipe 1 around the pipe axis, an induction heating coil (hereinafter sometimes simply referred to as the "coil") 12 that can simultaneously heat the end of the pipe body 2 and the flange 3, and a cutting device 21 that circumferentially cuts the coating 4 formed on the inner surface of the end of the pipe body.

[0049] In each drawing, mutually orthogonal two-dimensional or three-dimensional orthogonal coordinates representing the up-down, left-right, and front-back directions are appropriately displayed, and the following description will be based on these directions, but these directions are for the convenience of explanation and do not impose any limitations on the configuration of each part of the present invention (the same applies to the second embodiment described later). Furthermore, this embodiment corresponds to the first invention, and the second embodiment described later corresponds to the second invention.

[0050] The induction heating coil 12 has a pipe body heating coil section 13 formed by routing a conductor in a plane perpendicular to the up-down direction (in a plane parallel to the front-to-back and left-to-right directions), and a flange heating coil section 14 formed by routing a conductor in a plane perpendicular to the front-to-back direction (pipe axis direction) (in a plane parallel to the up-to-down and left-to-right directions), and the pipe body heating coil section 13 and the flange heating coil section 14 are shaped to be perpendicular to each other.

[0051] Therefore, when the pipe body heating coil section 13 is inserted into the inside of the pipe body 2 from one end thereof so as to face the inner peripheral surface of the end of the pipe body 2 (the upper inner peripheral surface in the examples shown in Figures 1 and 2, etc.), the flange heating coil section 14 faces the surface (rear surface) of the flange 3 (in other words, the flange heating coil section 14 is parallel to the flange 3).

[0052] The conductors of each coil section 13, 14 form a continuous conductive path (i.e., the pipe body heating coil section 13 and the flange heating coil section 14 are electrically connected in series), and this conductive path is physically (mechanically) supported and electrically connected by being welded at one end to one terminal 16a of the power supply unit 15, and is physically (mechanically) supported and electrically connected by being welded at the other end to the other terminal 16b of the power supply unit 15.

[0053] Furthermore, the number of turns of each coil portion 13, 14 is greater for the flange heating coil portion 14 than for the pipe body heating coil portion 13, and in this embodiment, the pipe body heating coil portion 13 has one turn, while the flange heating coil portion 14 has two turns. This is because the flange 3, which is thick and therefore difficult to heat up, is heated to the same extent at the same time as the pipe body 2, so that the coating 4 formed on the pipe body 2 and the coating 5 formed on the flange 3 can be peeled off together.

[0054] The conductors forming the coil portions 13 and 14 are hollow tubes made of a conductive material so that cooling water can be passed through the inside of the coil 12 to cool it when electricity is applied to the coil 12.

[0055] On the other hand, the cutting device 21 that cuts the coating 4 on the inner surface of the pipe body is equipped with a cutting device main body 22 that has a cutting blade 23 that cuts the coating 4 on the inner surface of the pipe body and can be inserted into the inside of the lining pipe 1, and a support rod 24 that supports the cutting device main body 22 inside the lining pipe 1.

[0056] The cutting blade 23 is a disk-shaped metal member with a blade formed on the periphery, and is supported by the cutting device body 22 so as to be rotatable about a support shaft 23a extending in the pipe axial direction (front-to-back direction) and to be biased (downward) toward the coating 4 on the inner circumferential surface of the pipe body. The cutting blade 23 makes an incision in the coating 4 on the inner circumferential surface of the lining pipe by pressing it against the inner circumferential surface (surface of the coating 4) of the lining pipe 1, and by rolling (moving circumferentially relative to the pipe body 2) on the inner circumferential surface of the lining pipe 1 (pipe body 2) as the lining pipe 1 rotates around the pipe axis, it cuts the coating 4 on the inner circumferential surface of the lining pipe in the circumferential direction.

[0057] The cutting blade 23 is positioned in the front-to-rear direction (pipe axis direction) so as to overlap with the pipe body heating coil section 13, that is, behind the front end of the pipe body heating coil section 13 and ahead of the midpoint in the front-to-rear direction of the pipe body heating coil section 13. This is to enable cutting of the coating 4 that has been heated and softened by the pipe body heating coil section 13.

[0058] In addition, the circumferential position of the cutting blade 23 is located away from the pipe body heating coil section 13 so as not to interfere with heating by the pipe body heating coil section 13, i.e., the pipe body heating coil section 13 is located at the upper circumferential end, while the cutting blade 23 is located at the lower circumferential end.

[0059] The rotating device 31 (see Figure 5 / not shown in other figures) that rotates the lining pipe 1 can have any structure as long as it can rotate the lining pipe 1 around the pipe axis (around the axis of the lining pipe 1).

[0060] As an example, as shown in Figure 5, a pair of rollers 32, 33 may be provided that support and rotate the pipe body 2 of the lining pipe 1 from below. Of the pair of rollers 32, 33, roller 32 is a drive roller that rotates the lining pipe 1, and the other roller 33 is a driven roller that rotates in response to the rotation of the lining pipe 1. A handle (not shown) is connected to the drive roller 32, and the drive roller 32 can be rotated by turning the handle by hand (see symbol R1). The lining pipe 1 rotates around the pipe axis in response to the rotation of the drive roller 32 (see symbol R2). The driven roller 33 rotates in response to the rotation of the lining pipe 1 (see symbol R3).

[0061] Instead of the manual method as described above, it is also possible to connect a power drive device such as an electric motor to the drive roller 32 and power drive the drive roller 32. Furthermore, in addition to the pair of rollers 32, 33, a pair of rollers (not shown), both of which are driven rollers, may be arranged at appropriate positions along the length of the lining pipe 1 so that the lining pipe 1 can be supported at multiple locations along its length (front-to-rear direction) (for example, at the front and rear ends of the lining pipe 1, and in addition to these, at one or more intermediate locations).

[0062] [First embodiment / coating removal method] A method for stripping the coatings 4, 5 from the lining pipe 1 using the coating stripping device 11 will now be described.

[0063] First, a flanged lining pipe 1, for example, a lining pipe 1 with deteriorated or damaged coatings 4, 5, is set on a rotating device 31 (supported between a pair of rollers 32, 33).

[0064] Next, the induction heating coil 12 and the cutting device 21 are placed at the end of the lining pipe 1. At this time, as shown in Figures 1 to 3 and 5, the pipe body heating coil portion 13 faces the inner peripheral surface of the pipe body 2, and the flange heating coil portion 14 faces the surface of the flange 3. At the same time, the cutting blade 23 of the cutting device 21 is pressed against the coating 4 on the inner peripheral surface of the pipe body.

[0065] Then, current is applied to the induction heating coil 12, and the rotating device 31 is driven (or the handle is turned if it is a manual type) to rotate the lining pipe 1 multiple times around the pipe axis. As the pipe body 2 rotates and comes to a position facing the pipe body heating coil section 13, it is heated by the coil section 13, and as the flange 3 comes to a position facing the flange heating coil section 14, it is heated by the coil section 14, so that the temperatures of the entire end (rear end) of the pipe body 2 and the entire flange 3 gradually rise.

[0066] The heating temperature by the induction heating coil 12 is preferably equal to or higher than the softening temperature of the coatings 4, 5 but lower than the temperature at which the coatings 4, 5 become viscous. The reason for heating at a temperature higher than the softening temperature of the coatings 4, 5 is to make it easier to peel the coatings 4, 5 from the adhered surfaces (the inner peripheral surface of the pipe body 2 and the surface of the flange 3) and to make it easier to cut the coating 4 with the cutting blade 23. The reason for heating at a temperature lower than the viscous temperature is to prevent the coatings 4, 5 peeled from the adhered surfaces from sagging and adhering to the induction heating coil 12, or to prevent the coating 4 from adhering to the cutting blade 23 and interfering with cutting.

[0067] Simultaneously with the heating operation, the coating 4 on the inner peripheral surface of the pipe body is cut in the circumferential direction by the cutting blade 23, so that the coatings 4, 5 on the end portions of the lining pipe 1, including the flange portion, are separated.

[0068] The coatings 4, 5 cut and separated by the cutting blade 23 can be peeled off using an appropriate tool (capable of hooking or gripping the coatings 4, 5 and pulling them out) and pulled out from the pipe body 2. If the lining pipe 1 also has a flange at the front end, the coating can be removed from the front end as well using the coating peeling device 11. The coating in the middle part of the pipe body 2 can be removed using another (existing / known) peeling device.

[0069] The above method can be used to manufacture, for example, a stripped pipe (a metal pipe with the coating removed) that can be used as the raw material (raw material) for a regenerated lined pipe. To produce a regenerated lined pipe, a new coating can be formed on the stripped pipe by a known method.

[0070] As described above, the coating removal device and coating removal method of this embodiment can separate the coating from the lining pipe end (the pipe body end and the flange) and efficiently remove both the coating from the pipe body end and the coating from the flange surface. Furthermore, this embodiment can heat the metal part close to the object to be removed (the coating on the inner circumferential surface of the pipe body and the flange surface), so heating efficiency is also good.

[0071] [Second embodiment / coating peeling device] 6 shows a coating stripping device according to a second embodiment. As shown in this figure, the coating stripping device according to the second embodiment includes a rotating device, an induction heating coil 12, and a cutting device, similar to the coating stripping device according to the first embodiment. The rotating device and the cutting device have the same structures as those in the first embodiment, but the arrangement of the induction heating coil 12 is different.

[0072] Specifically, the induction heating coil 12 has a pipe body heating coil section 13 that faces the outer peripheral surface of the pipe body 2 (in this embodiment, the upper outer peripheral surface), and a flange heating coil section 14 that faces the back surface (front surface) of the flange 3. As in the first embodiment, the pipe body heating coil section 13 and the flange heating coil section 14 are formed continuously from a continuous conductor, and the number of turns of the flange heating coil section 14 is greater than the number of turns of the pipe body heating coil section 13. Also, the rotating device, cutting device, and cutting blade are not shown in Figure 6.

[0073] The cutting blade included in the cutting device is positioned in the front-to-back direction so as to overlap with the pipe body heating coil section 13 (a position rearward of the front end of the pipe body heating coil section 13 and forward of the midpoint of the pipe body heating coil section 13 in the front-to-back direction) so as to be able to cut the coating that has been heated and softened by the pipe body heating coil section 13, as in the first embodiment.

[0074] According to this embodiment, even if the coating formed on the inner surface of the pipe body 2 and the surface (rear surface) of the flange 3 bulges or sags as a result of heating the lining pipe 1, the pipe body heating coil section 13 is positioned outside the pipe body 2, and the flange heating coil section 14 is positioned on the back surface of the flange 3, which is the surface opposite to the coating formation surface, so there is no risk of the coating coming into contact with these. [Explanation of symbols]

[0075] 1. Lining pipe 2. Tube body 3 flange 4,5 Coating 11 Film stripping device 12 induction heating coil 13 Pipe body heating coil 14 Flange heating coil section 15 Power supply 16a, 16b terminals 21 Cutting device 22 Cutting device body 23 Cutting blade 23a Support shaft 24 Support rod 31 Rotating device 32 Drive roller 33 Driven roller

Claims

1. A coating stripping method for stripping a coating from a lining pipe, comprising: The lining pipe is A tube body; a flange provided on at least one end of the pipe body; a coating formed on at least the inner circumferential surface of the pipe body and the surface of the flange; It is equipped with The coating peeling method includes: a rotation operation of rotating the lining pipe around the pipe axis; a pipe body heating operation of heating one end of the pipe body from the inside of the pipe body; a flange heating operation of heating the flange from the surface side of the flange; a cutting operation in which an incision is made in the coating at one end of the pipe body so that the coating at one end of the pipe body is cut in a circumferential direction by rotating the lining pipe by the rotating operation; Including a heating and cutting process that simultaneously performs A coating peeling method characterized by the above.

2. The pipe body heating operation and the flange heating operation are performed using an induction heating coil; The induction heating coil is a pipe body heating coil portion that can be arranged to face the inner circumferential surface of the pipe body; a flange heating coil portion that can be arranged to face the surface of the flange; have The coating stripping method according to claim 1.

3. The pipe body heating coil portion and the flange heating coil portion are formed in a continuous manner by a continuous conductor. The coating stripping method according to claim 2.

4. The number of turns of the flange heating coil portion is greater than the number of turns of the pipe body heating coil portion. The coating peeling method according to claim 2 or 3.

5. The pipe body heating operation and the flange heating operation are carried out at a temperature equal to or higher than the temperature at which the coating softens and lower than the temperature at which the coating becomes viscous. The coating stripping method according to any one of claims 1 to 3.

6. The cutting point, which is the place where the incision is made in the incision operation, A position that overlaps with the heating range of the pipe body heating coil portion in the pipe axial direction of the pipe body and is outside the heating range of the pipe body heating coil portion in the circumferential direction of the pipe body. to make it so that The coating peeling method according to claim 2 or 3.

7. The cutting operation is performed by pressing a cutting blade against the coating. The coating stripping method according to claim 6.

8. A coating stripping method for stripping a coating from a lining pipe, comprising: The lining pipe is A tube body; a flange provided on at least one end of the pipe body; a coating formed on at least the inner circumferential surface of the pipe body and the surface of the flange; It is equipped with The coating peeling method includes: a rotation operation of rotating the lining pipe around the pipe axis; a pipe body heating operation of heating one end of the pipe body from the outside of the pipe body; a flange heating operation of heating the flange from a back surface side of the flange; a cutting operation in which an incision is made in the coating at one end of the pipe body so that the coating at one end of the pipe body is cut in a circumferential direction by rotating the lining pipe by the rotating operation; and a heating and cutting step simultaneously performed. The pipe body heating operation and the flange heating operation are performed using an induction heating coil; The induction heating coil is a pipe body heating coil portion that can be arranged to face the outer peripheral surface of the pipe body; a flange heating coil portion that can be arranged to face the back surface of the flange; have A coating peeling method characterized by the above.

9. A method for producing a coated pipe by peeling and removing a coating from a lined pipe, comprising: The lining pipe is A tube body; a flange provided on at least one end of the pipe body; a coating formed on at least the inner circumferential surface of the pipe body and the surface of the flange; It is equipped with The method comprises: providing the lining pipe; After the step of preparing the lining pipe, a heating and cutting step is performed simultaneously, which includes a rotation operation of rotating the lining pipe around the pipe axis, a pipe body heating operation of heating one end of the pipe body from the inside of the pipe body, a flange heating operation of heating the flange from the surface side of the flange, and a cutting operation of making an incision in the coating at one end of the pipe body so that the coating at one end of the pipe body is cut in the circumferential direction by rotating the lining pipe through the rotation operation. Contains A method for manufacturing a coating peeled tube, comprising:

10. A coating removal device for removing a coating from a lining pipe having a flange at an end of a pipe body and having a coating on at least an inner circumferential surface of the pipe body and a surface of the flange, comprising: a rotating device that rotates the lining pipe around the pipe axis; an induction heating coil capable of simultaneously heating the end of the pipe body and the flange; a cutting device that makes cuts in the coating on the end portion of the pipe body so that the coating on the end portion of the pipe body is cut in the circumferential direction by rotating the lining pipe by the rotating device; Equipped with The induction heating coil is a pipe body heating coil portion disposed opposite to an inner peripheral surface of the end portion of the pipe body and capable of heating the end portion of the pipe body; a flange heating coil portion that is disposed opposite to the surface of the flange and is capable of heating the flange; have A coating peeling device characterized by:

11. The pipe body heating coil portion and the flange heating coil portion are formed in a continuous manner by a continuous conductor. The coating stripping device according to claim 10.

12. The number of turns of the flange heating coil portion is greater than the number of turns of the pipe body heating coil portion. The coating stripping device according to claim 11.

13. The cutting point, which is the location where the incision is made by the incision device, A position that overlaps with the heating range of the pipe body heating coil portion in the pipe axial direction of the pipe body and is outside the heating range of the pipe body heating coil portion in the circumferential direction of the pipe body. Located in The coating stripping device according to any one of claims 10 to 12.

14. the incision device has a cutting blade that can incise the coating by pressing it against the coating at the incision point; The cutting blade is A position that overlaps with the pipe body heating coil portion in the pipe axis direction of the pipe body and is out of contact with the pipe body heating coil portion in the circumferential direction of the pipe body. is located in The coating stripping device according to claim 13.

15. A coating removal device for removing a coating from a lining pipe having a flange at an end of a pipe body and having a coating on at least an inner circumferential surface of the pipe body and a surface of the flange, comprising: a rotating device that rotates the lining pipe around the pipe axis; an induction heating coil capable of simultaneously heating the end of the pipe body and the flange; a cutting device that makes cuts in the coating on the end portion of the pipe body so that the coating on the end portion of the pipe body is cut in the circumferential direction by rotating the lining pipe by the rotating device; Equipped with The induction heating coil is a pipe body heating coil portion disposed opposite to the outer peripheral surface of the end portion of the pipe body and capable of heating the end portion of the pipe body; a flange heating coil portion that is disposed opposite the rear surface of the flange and is capable of heating the flange; have A coating peeling device characterized by:

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