Pseudo socket for pipe

Abstract

To facilitate inner surface processing or outer surface processing of a housing pipe having no socket or insertion port.SOLUTION: A pseudo socket for a pipe body attached to an end part 12 of a pipe body 10, comprises a base part 31 fixed to an outer periphery of the end part 12, and an annular projection part 32 provided adjacent to the base part 31. When attached to the tube body 10, the projection part 32 projects outward in a pipe axis direction with respect to the end part 12, and an outer surface 32a of the projection part 32 has a larger diameter than an outer peripheral surface 10a of the pipe body 10. A material facing at least an outward side end surface 32c of the projection part 32 is metal.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This invention relates to a pseudo socket attached to the end of a tubular body.

Background Art

[0002] As a cast iron pipe (metal pipe), for example, as shown in FIG. 9, a pipe body 1 is common in which one end of a cylindrical straight pipe portion having a constant inner and outer diameter is a socket 2 and the other end is an insertion port 3. The insertion port 3 of another pipe body 1 is inserted into the inner surface of the socket 2 of the pipe body 1, and the two pipe bodies 1, 1 are connected. At this time, the lock ring fitted on the inner surface of the socket 2 of one pipe body 1 engages with the protrusion on the outer surface of the insertion port 3 of the other pipe body 1, so that the pipe bodies 1, 1 are prevented from coming out.

[0003] As this type of pipe body 1, there is a cast iron pipe cast by a centrifugal casting method. In the centrifugal casting method, molten metal (molten metal) is poured into a cylindrical mold while it is rotating at high speed, and the molten metal is pressurized by the centrifugal force accompanying the rotation of the mold to manufacture the pipe body 1. After that, annealing is performed on the pipe body 1, and scale removal treatment, flaw detection inspection as necessary, detailed shape treatment of the outer surface of the insertion port 3 and the inner surface of the socket 2, rust prevention painting, inner surface treatment such as powder painting or mortar lining on the inner surface (including its base treatment), outer surface treatment such as synthetic resin painting (including its base treatment), and various other treatments are performed.

[0004] Also, for the purpose of minimizing the axial movement of members during pipe connection and pipe removal, a pipe body 10 corresponding to a housing type joint may be adopted (Patent Document 1). The pipe body 10 corresponding to the housing type joint (hereinafter referred to as a housing pipe) has no portion corresponding to a socket as shown in FIG. 10, and both ends in the pipe axis direction have a cylindrical shape with a constant pipe diameter. The cylindrical ends are opposed to each other along the pipe axis direction, and an annular housing joint is fitted on the outer periphery of the opposing portions of the pipe bodies 10, 10 and tightened in the inner diameter direction, so that the pipe bodies 10, 10 are connected. Therefore, there is an advantage that it is not necessary to move the pipe body 10 along the pipe axis direction during pipe connection and pipe removal.

[0005] For example, in confined work spaces such as tunnels, it is not possible to lift components with a crane, making it difficult to move the pipe body 1 relative to the socket 2 and the insertion 3 in the pipe axis direction, as in conventional methods. In such work environments, using a housing pipe and housing joint minimizes the movement of the housing pipe in the pipe axis direction during pipe connection and removal, improving work efficiency. Furthermore, projections 11 are provided on the outer circumference of both ends of the housing pipe in the pipe axis direction to position the housing joint in the pipe axis direction. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2021-148266 [Overview of the project] [Problems that the invention aims to solve]

[0007] As mentioned above, the pipe body 1, which is made of cast iron, undergoes various internal and external treatments during the post-casting process. In the case of a pipe body 1 having a socket 2 and a spigot 3 (hereinafter referred to as a normal pipe), these internal and external treatments are often performed while rotating the pipe body 1 using a device as shown in Figure 9. As shown in Figure 9, the pipe body 1 is placed on a roller 21, and by rotating the roller 21 with a driving force, the pipe body 1 rotates around the pipe axis in the direction of arrow B. At this time, while rotating around the pipe axis, the pipe body 1 moves in the direction of the pipe axis due to the thrust load as shown by arrow A. Here, the pipe end on the socket 2 side hits the stopper 22, preventing the pipe body 1 from moving in the direction of the pipe axis during the work. The stopper 22 rotates in the direction of arrow c, following the rotation of the pipe body 1 around the pipe axis.

[0008] However, problems arise when using such equipment to process housing pipes that do not have a receiving port 2 and a threading port 3. When the pipe body is a housing pipe, for example, as shown in Figure 10, even if the pipe diameter w is the same as that of a normal pipe, the axial end of the housing pipe may not come into contact with the stopper 22. For this reason, it is necessary to add a moving device to move the stopper 22 to the desired position, or to install equipment specifically for handling housing pipes, separate from the equipment for handling pipe bodies 1 that have a receiving port 2 and a threading port 3.

[0009] Furthermore, even if a moving device for the stopper 22 is added, or if equipment specifically for handling housing pipes is installed, various problems may arise in the internal and external surface treatment of the housing pipes. For example, as shown in Figure 11, because the end of the pipe body 10 is in contact with the stopper 22, the grinding wheel may not be able to contact the end of the inner surface of the housing pipe during the internal grinding process. Also, in the powder coating process during internal surface treatment, there is a problem that areas near the end of the housing pipe in contact with the stopper 22 (part E in the figure) cannot be powder coated. Reference numeral 23 in Figure 11 indicates nozzle a which discharges the powder coating paint, and the paint discharged from nozzle a will not adhere to the part of the housing pipe in contact with the stopper 22, or even if it does adhere, the contact with the stopper 22 will cause uneven coating.

[0010] Therefore, the objective of this invention is to facilitate the surface treatment of a pipe body (housing pipe) that does not have a socket or a spigot. [Means for solving the problem]

[0011] To solve the above problems, this invention provides a pseudo-receptacle for a pipe body that is attached to the end of a pipe body, comprising a base fixed to the outer circumference of the end, and an annular projection provided adjacent to the base, wherein, when attached to the pipe body, the projection protrudes outward in the pipe axis direction from the end, and the outer surface of the projection has a larger diameter than the outer surface of the pipe body, and at least the material facing the outer end face of the projection is metal.

[0012] Here, the base portion is annular in shape and has at least one slit along its circumferential direction, and is provided with a fastening means between opposing portions that sandwich the slit in the base portion, and the base portion can be fastened and fixed to the outer circumference of the end portion by the fastening means.

[0013] In this case, the fastening means can be configured such that, in the installed state, the bolt is inserted into the through hole and screwed into the female thread portion, and the bolt is inserted into the female thread portion and screwed into the female thread portion.

[0014] In each of these embodiments, the base portion and the protruding portion can be configured such that they are separated by a circumferential slit in a predetermined direction around the pipe axis, with the slit in between, and connected in other directions.

[0015] A surface treatment method for a pipe body using a pseudo socket for a pipe body comprising each of these embodiments is employed, wherein the base is fastened and fixed to the outer circumference of the end of the pipe body by the fastening means, the protruding portion protrudes outward in the direction of the pipe axis from the end, and the outer surface of the protruding portion has a larger diameter than the outer surface of the pipe body, the pipe body is placed on a roller, the protruding portion is brought into contact with a stopper, and while rotating the pipe body around the pipe axis, one or more surface treatments selected from polishing, grinding, painting, and lining are performed on the inner surface or end surface of the pipe body. [Effects of the Invention]

[0016] According to this invention, the surface treatment of a tubular body (housing pipe) without a receiving port and an insertion port can be easily performed.

Brief Description of the Drawings

[0017] [Figure 1] Vertical sectional view showing the usage state of the pseudo-receiving port of the first embodiment in this invention [Figure 2] Front view showing the pseudo-receiving port of the first embodiment [Figure 3] Left side view of FIG. 2 [Figure 4] Plan view of FIG. 2 [Figure 5] Perspective view showing the pseudo-receiving port of the first embodiment [Figure 6] Enlarged sectional view of the main part showing the usage state of the pseudo-receiving port of the second embodiment in this invention [Figure 7] Enlarged sectional view of the main part showing the usage state of the pseudo-receiving port of the second embodiment in this invention [Figure 8] Enlarged sectional view of the main part showing the usage state of the pseudo-receiving port of the second embodiment in this invention [Figure 9] Schematic diagram of equipment for handling the inner surface treatment or outer surface treatment of a tubular body (ordinary pipe) having a receiving port and an insertion port [Figure 10] Schematic diagram showing the state of handling a tubular body (housing pipe) without a receiving port and an insertion port with the equipment of FIG. 9 [Figure 11] Schematic diagram showing the state of handling a tubular body (housing pipe) without a receiving port and an insertion port with existing equipment

Modes for Carrying Out the Invention

[0018] Embodiments of this invention will be described based on the drawings. Figure 1 shows a pseudo-socket 30 for a pipe (hereinafter simply referred to as pseudo-socket 30) according to the first embodiment of this invention attached to a pipe 10, a so-called housing pipe, which does not have a socket or a socket. The pipe 10 in this embodiment is assumed to be a housing pipe used for water supply piping in fire extinguishing piping structures in tunnels, but the use of the pipe 10 is not limited to this. Furthermore, the pipe 10 in this embodiment is assumed to be a ductile cast iron pipe manufactured by centrifugal casting, but other cast iron pipes or other metal pipes may also be used.

[0019] As shown in Figure 1, the pipe body 10 has a straight pipe section with a circular cross-section and the same diameter along its entire length, and both ends of the straight pipe section in the axial direction are end portions 12 that serve as connection points to another adjacent pipe body 10. The end portions 12 have the same outer and inner diameters as the straight pipe section. A projection 11 corresponding to a housing joint (not shown) is provided on the outer circumferential surface of the end portions 12. The axial end of the annular housing joint strikes the projection 11, thereby positioning the housing joint and the pipe body 10 in the axial direction (the same applies to the other pipe body 10 to be connected). In this embodiment, the projection 11 is a ridge continuously provided around the entire circumference of the pipe body 10 around the pipe axis, but the projection 11 may be provided only in a part of the circumference around the pipe axis.

[0020] The pseudo-receptacle 30 is a single piece of molded metal that is attached to the outer circumference of the end 12 of the pipe body 10. As shown in Figures 2 to 5, the pseudo-receptacle 30 is composed of a base portion 31 with a C-shaped cross-section that is annular and has a slit 34 at one location in the circumferential direction, an annular projection portion 32 provided adjacent to the base portion 31, and a tightening means 50 provided between opposing portions 33, 33 that sandwich the slit 34 in the base portion 31. The slit 34 penetrates the pseudo-receptacle 30 both internally and externally.

[0021] The base portion 31 and the protruding portion 32 are separated by a circumferential slit 40 in a predetermined direction around the pipe axis, with the slit 34 in between. In this embodiment, the circumferential slit 40 is a groove 42 that is symmetrical along the circumferential direction with respect to the slit 34. The groove 42 penetrates the pseudo-receiving opening 30 both ways. Furthermore, the groove 42 is oriented at 90 degrees around the pipe axis from the center line of the slit 34 to the end portions 41, 41 on both sides. That is, the circumferential slit 40 is formed at 180 degrees around the pipe axis. In directions other than the portion where the circumferential slit 40 is provided, the base portion 31 and the protruding portion 32 are connected and form a single integrated member. The portion where the base portion 31 and the protruding portion 32 are connected will be hereinafter referred to as the connecting portion 35. For this reason, the base portion 31 is composed of a connecting portion 35 made of an arc-shaped member and arc-shaped opposing portions 33, 33 protruding from both circumferential ends of the connecting portion 35.

[0022] As shown in Figure 2, the fastening means 50 consists of a female threaded portion 53a provided on one of the opposing portions 33, 33 and a through hole 53b provided on the other, and a bolt 52 that is screwed into the female threaded portion 53a. By inserting the shaft of the bolt 52 through the through hole 53b from the other opposing portion 33 side and screwing the shaft into the female threaded portion 53a, the opposing portions 33, 33 are tightened in a direction that brings them closer together. As shown in Figure 1, in the state in which the pseudo-receptacle 30 is attached to the pipe body 10 (hereinafter referred to as the attached state), the head and shaft of the bolt 52 are recessed into the inner diameter side of the outer surface 31a of the base portion 31. The female threaded portion 53a and the through hole 53b are formed on the inner circumference of the holes 51 provided on both opposing portions 33, 33, but are not formed in the part into which the head of the bolt 52 is inserted. Of the hole 51, the portion into which the head of the bolt 52 fits is a large-diameter portion 54, which has a slightly larger inner diameter than the female thread portion 53a and the through hole 53b.

[0023] The base 31 is fastened and fixed to the outer circumference of the end 12 of the pipe body 10 in the direction of the pipe axis by the fastening means 50. At this time, the inner surface 31b of the base 31 is in close contact with the outer surface 10a of the pipe body 10, and the end surface 31c of the base 31 may be in contact with the side surface of the projection 11 of the pipe body 10, but by inserting it to the vicinity of the side surface of the projection 11 as a reference, the pseudo-receptacle 30 and the pipe body 10 are positioned in the direction of the pipe axis. In this mounting state, the outer surface 31a of the base 31 is located on the outer diameter side by a radial distance L1 (see Figure 1) from the outer surface 10a of the pipe body 10 (it is larger in diameter), and is also located on the outer diameter side by a radial distance L2 (see Figure 1) from the outer surface of the projection 11 (it is larger in diameter). Note that in some places, the radial distances L1 and L2 are slightly reduced due to the fastening in the inner diameter direction by the fastening means 50.

[0024] Furthermore, in this installed state, the protruding portion 32 protrudes outward in the axial direction from the end face 10c of the end 12 of the pipe body 10 by a distance L3 (see Figure 1) in the axial direction, and the outer surface 32a of the protruding portion 32 is located on the outer diameter side by a radial distance L1 (see Figure 1) from the outer circumferential surface 10a of the pipe body 10 (it is large in diameter), and is also located on the outer diameter side by a radial distance L2 (see Figure 1) from the outer circumferential surface of the projection 11 (it is large in diameter).

[0025] As described above, the pipe body 10, which is made of cast iron, undergoes various internal and external treatments in the post-casting process. Here, for pipe bodies 10 that are housing pipes without sockets or slits, the above-mentioned pseudo-socket 30 is attached and the treatment is carried out. Since the pseudo-socket 30 is attached to the pipe body 10, as long as the pipe body 10 is a housing pipe with the same or close diameter as conventionally used ordinary pipes, the internal and external treatments of the pipe body 10 can be carried out using the same equipment used for conventional pipes (see Figure 6) (see Figure 1). Here, it is desirable that the amount of protrusion of the pseudo-socket 30 toward the outer diameter and the amount of protrusion toward the pipe axis (the radial distance L1 and pipe axis distance L3 mentioned above) relative to the pipe body 10 be equal to the amount of protrusion of the socket 2 toward the outer diameter and the amount of protrusion toward the pipe axis relative to the straight pipe section of the normal pipe handled by the device. However, as long as it does not hinder the work, it is not necessary to exclude the possibility of a difference in the amount of protrusion toward the outer diameter and the pipe axis between the two. This eliminates the need to add a device to move the stopper 22 to the conventional device or to set up separate equipment specifically for handling housing pipes, which can contribute to cost reduction.

[0026] Note that in Figure 1, the roller 21 shown in Figure 9 is omitted from the illustration. In Figure 1, the roller 21 (not shown) is rotated by a driving force, causing the pipe body 10 to rotate around its axis. As the pipe body 10 rotates around its axis, it moves in the direction of the pipe axis due to the thrust load, and the end 32c of the pseudo-receiving opening 30 comes into contact with the stopper 22, thereby restricting the movement of the pipe body 10 in the direction of the pipe axis during operation. Similarly, the stopper 22 rotates in accordance with the rotation of the pipe body 10 around its axis.

[0027] In other words, in this invention, the following method can be adopted as a surface treatment method for the pipe body 10 using the pseudo-receptacle 30. First, the base portion 31 is tightened and fixed to the outer circumference of the end portion 12 of the pipe body 10 in the direction of the pipe axis by the tightening means 50, the protruding portion 32 protrudes outward in the direction of the pipe axis from the end portion 12 of the pipe body 10, and the outer surface 31a of the protruding portion 32 is larger in diameter than the outer surface 10a of the pipe body 10. The pipe body 10 is then placed on the roller 21, the protruding portion 32 is brought into contact with the stopper 22, and various surface treatments are performed on the inner surface 10b or end surface 10c of the pipe body 10 while rotating the pipe body 10 around the pipe axis.

[0028] In Figure 1, the end 12 of the pipe body 10 does not directly contact the stopper 22, but the protruding portion 32 of the pseudo-receptacle 30 contacts the stopper 22, allowing the grinding wheel 24 to contact the entire inner surface of the pipe body 10 during the intermediate grinding process for internal surface treatment. In other words, it prevents the grinding wheel 24 from failing to contact the end of the inner surface 10b of the pipe body 10. Furthermore, the protruding portion 32 of the pseudo-receptacle 30 contacting the stopper 22 allows the paint to spread throughout the entire inner surface 10b and end surface 10c of the pipe body 10 during the painting process. This is because the stopper 22 does not cover the end surface 10a of the pipe body 10. This prevents unevenness in various types of paint. For these reasons, by using the pseudo-receptacle 30, various treatments such as polishing, grinding, painting, and lining can be easily and appropriately performed on the inner surface 10b or end surface 10c of the pipe body 10.

[0029] In the above embodiment, the circumferential slits 40 are oriented at 90 degrees around the pipe axis from the center line of the slit 34 to the end portions 41, 41, but the range in which the circumferential slits 40 are provided can be increased or decreased as appropriate. For example, the circumferential slits 40 may be oriented at 60 degrees and 120 degrees around the pipe axis from the center line of the slit 34 to the end portions 41, 41, respectively. Furthermore, if the slit 34 is extended to provide slits 34 in the protruding portion 32, the machining procedure for cutting the slits 34 becomes easier.

[0030] Furthermore, in the above embodiment, the fastening means 50 is composed of a female threaded portion 53a provided on one of the opposing portions 33, 33 and a through hole 53b provided on the other, and a bolt 52 screwed into the female threaded portion 53a. However, the embodiment is not limited to this, and various fastening means 50 using screws such as bolts and nuts, or fastening means 50 using various other mechanisms may be adopted. However, it is desirable that the components constituting the fastening means 50 are inserted inward from the outer surface 31a of the base portion 31 when the pseudo-receptacle 30 is fixed to the pipe body 10. Also, the material constituting the pseudo-receptacle 30 is not particularly limited, but for example, if the surface treatment is performed at room temperature, rubber or resin materials that are easy to install can be used, and if the surface treatment requires heating, it is desirable to use metal. However, at least the material facing the outer end face 32c of the protruding portion 32 is required to be metal, assuming that it will come into contact with the stopper 22.

[0031] Furthermore, in the above embodiment, the base 31 is configured to have one slit 34 along its circumferential direction, but for example, the number of slits 34 may be two or three or more along its circumferential direction. In this case, a fastening means 50 will be installed for each of the slits 34. For example, if there are two slits 34 along the circumferential direction, the base 31 is fixed to the outer circumference of the end 12 of the pipe body 10 by fastening the opposing parts 33, 33 that sandwich each slit 34 with the fastening means 50. Here, if each slit 34 is extended and a slit 34 is also provided in the protruding part 32, the pseudo-receiving opening 30 consisting of the base 31 and the protruding part 32 becomes a two-part member divided along the circumferential direction, making it even easier to attach to the outer circumference of the end 12 of the pipe body 10.

[0032] A second embodiment of this invention is shown in Figures 6 to 8. In the second embodiment, the slit 34 provided in the base 31 is omitted, and the material of the base 31 is made of an elastically deformable material such as rubber or resin, so that the base 31 can be fitted and fixed to the outer circumference of the end 12 of the pipe body 10. Specifically, the inner surface of the base 31 is elastically deformed to expand outwards, and in that state, the base 31 is fitted over the protrusion 11 and onto the outer circumference of the pipe body 10. Then, by releasing the external force that was expanding the base 31, the base 31 comes into close contact with the outer surface of the end 12 of the pipe body 10. At this time, the protrusion 11 of the pipe body 10 enters into the recess 31e on the inner surface of the base 31, thereby positioning the pseudo-receiving port 30 relative to the pipe body 10 and preventing it from falling off.

[0033] In this embodiment, the inner portion 32d of the protruding portion 32 is formed from an elastically deformable material integral with the base portion 31, and the material of the end face portion 32e facing the outer end face 32c of the protruding portion 32 is metal (metal plate). The reason why the material of the end face portion 32e is metal is that when it comes into contact with the stopper 22, if the material of the contacting portion is resin or rubber, it will have poor durability and will wear and be damaged significantly. For this reason, the material of the end face portion 32e is metal (iron in this embodiment).

[0034] In the state in which the pseudo-receptacle 30 is attached to the pipe body 10, the protruding portion 32 protrudes outward in the pipe axis direction from the end portion 12, and the outer surface 32a of the protruding portion 32 has a larger diameter than the outer surface 10a of the pipe body 10, as in the first embodiment.

[0035] Figure 6 is a schematic diagram showing the work process of mortar lining. Reference numeral 23 in the figure indicates the supply pipe b from which the mortar is dispensed. By using the pseudo-socket 30, the end 12 of the pipe body 10 does not directly contact the stopper 22, and the protruding portion 32 of the pseudo-socket 30 contacts the stopper 22, so that the mortar for mortar lining dispensed from the supply pipe b spreads over the entire inner surface of the pipe body 10. Here, since the inner surface 32b of the protruding portion 32 protrudes by a dimension e inward from the finished surface of the mortar lining layer b', the protruding portion 32 also functions as a formwork for forming the mortar lining layer b' by preventing the mortar from leaking out.

[0036] Figure 7 is a schematic diagram showing the process of removing laitance deposited on the surface of the mortar lining layer b'. Reference numeral 23 in the figure indicates the polishing part (grinding wheel) c used to remove the laitance. By using the pseudo-receptacle 30, the end 12 of the pipe body 10 does not directly contact the stopper 22, and the protruding part 32 of the pseudo-receptacle 30 contacts the stopper 22, allowing the polishing part (grinding wheel) c to contact the entire inner surface of the pipe body 10. Here, since the inner surface 32b of the protruding part 32 is flush with the finished surface of the mortar lining layer b', the polishing part (grinding wheel) c can finish the surface of the mortar lining layer b' up to the edge of the end 12 of the pipe body 10.

[0037] Figure 8 is a schematic diagram showing the process of forming a seal coat layer on the surface of the mortar lining layer b' on the inner surface of the pipe body 10. The seal coat layer is formed by applying a seal coat agent to the surface of the mortar lining layer b' with the aim of preventing the evaporation of moisture in the mortar (assisting with curing) and improving durability. The inner surface 32b of the protruding portion 32 is flush with the finished surface of the seal coat layer. Reference numeral 23 in Figure 8 indicates a nozzle d that discharges the seal coat agent, and the seal coat agent discharged from the nozzle d is designed to ensure that it reaches all the way to the edge of the end portion 12 of the pipe body 10.

[0038] In the examples shown in Figures 6 to 8, the pseudo-receptacle 30 is fixed to the end 12 of the pipe body 10 by a snap-fit ​​fixation method involving elastic deformation of the base 31 material, but other fixing methods may be adopted. For example, a method can be used in which an arc-shaped base 31 divided into multiple parts along the circumferential direction, or a C-shaped base 31 with a slit 34 in the circumferential direction, similar to the first embodiment, is placed on the outer circumference of the end 12 of the pipe body 10, a band is wrapped around the outer surface of the base 31 as a tightening means 50, and the base 31 is fixed to the pipe body 10 by tightening it toward the inner diameter with the band. Alternatively, a screw member such as a bolt or screw can be used instead of a band. In this case, a method can also be considered in which the screw member is screwed from the outer surface 31a of the base 31 toward the inner surface 31b, and the tip of the screw member is brought into contact with the outer surface 10a of the pipe body 10 to fix the base 31 to the pipe body 10. In these cases, elastic deformation performance is not necessarily required for the base 31, so any material can be used for the base 31. [Explanation of Symbols]

[0039] 10. Body 11. Protrusion 12 End 30 Pseudo socket 31 Base 31a External surface 32 Overhang 33 Opposing section 34 slits 40 circumferential slits 50 Fastening means 52 volts 53a Female thread section 53b Through hole

Claims

1. A pseudo-receptacle for a pipe body, which is attached to the end (12) of the pipe body (10), A base portion (31) fixed to the outer circumference of the end portion (12), An annular projection (32) is provided adjacent to the base (31), Equipped with, In the state in which it is attached to the pipe body (10), the protruding portion (32) protrudes outward in the direction of the pipe axis from the end portion (12), and the outer surface (32a) of the protruding portion (32) has a larger diameter than the outer circumferential surface (10a) of the pipe body (10), and the material facing at least the outer end surface (32c) of the protruding portion (32) is metal, a pseudo socket for a pipe body.

2. The base portion (31) is annular in shape and has at least one slit (34) along its circumferential direction. The base portion (31) is provided with a fastening means (50) between opposing portions (33, 33) that sandwich the slit (34), The pseudo socket for a pipe according to claim 1, wherein the base (31) is tightened and fixed to the outer circumference of the end (12) by the tightening means (50).

3. The pseudo socket for a pipe according to claim 2, wherein the fastening means (50) comprises a female threaded portion (53a) provided on one of the opposing portions (33, 33) and a through hole (53b) provided on the other, and a bolt (52) inserted through the through hole (53b) and screwed into the female threaded portion (53a), and in the installed state, the bolt (52) is inserted inward from the outer surface (31a) of the base portion (31).

4. The pseudo socket for a pipe according to claim 2 or 3, wherein the base portion (31) and the protruding portion (32) are separated by a circumferential slit (40) in a predetermined direction around the pipe axis, with the slit (34) in between, and connected in other directions.

5. A method for surface treatment of a pipe using a pseudo socket for a pipe according to any one of claims 2 to 4, The base portion (31) is fastened and fixed to the outer circumference of the end portion (12) of the pipe body (10) by the fastening means (50), the protruding portion (32) protrudes outward in the pipe axis direction from the end portion (12), and the outer surface (32a) of the protruding portion (32) has a larger diameter than the outer surface (10a) of the pipe body (10), A method for surface treatment of a pipe, comprising placing the pipe (10) on a roller (21), bringing the protruding portion (32) into contact with a stopper (22), and performing one or more surface treatments selected from polishing, grinding, painting, and lining on the inner surface (10b) or end surface (10c) of the pipe (10) while rotating the pipe (10) around its axis.

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