JP5194153B2 - Pipe end anticorrosion joint and method for manufacturing the same - Google Patents

Description

  The present invention relates to a pipe end anticorrosion joint mainly used in a water supply piping system and a method for manufacturing the same.

  Conventionally, as shown in FIG. 3, a screw-type malleable cast iron pipe joint is used as a joint body 101, which is formed on the inner periphery of the end of the joint body 101 and is formed on the outer periphery of the end of the steel pipe 141. Fluorine such as polytetrafluoroethylene (hereinafter referred to as “PTFE”) over the entire thread length of the internal thread portion (female thread portion: taper thread portion for tube) 111 into which the thread portion: taper thread portion for tube 143 is screwed. A joint (hereinafter referred to as “pre-coated joint”) in which a seal layer 110 is formed on the entire surface of the inner threaded portion 111 of the joint body 101 by baking and painting a sealing agent made of a resin (for example, Patent Document 1). ) 100.

  The greatest feature of the precoat joint 100 is that when connecting the steel pipe 141, it is possible to save the trouble of applying the liquid sealant around the threaded portion 143 of the steel pipe 141 and winding the seal tape (PTFE tape). .

  Since the seal layer 110 (precoat) formed (applied) in advance on the inner threaded portion 111 of the precoat joint 100 cannot cover the end surface 144 of the connected steel pipe 141, the precoat joint 100 is rusted from the pipe end surface. In addition, there is no one for water supply (water supply, miscellaneous water) piping systems (for lining steel pipes to be described later) in which generation of red water (rust) is a problem. Even if the precoat joint 100 is used in a water supply piping system, a liquid sealant must be applied to the pipe end face, and the maximum characteristics of the precoat joint 100 are halved or lost. In this respect, there is no precoat joint 100 for a water supply piping system. The precoat joint 100 is used for piping systems such as water (excluding drinking water) and air. There are many types of pre-coated joints 100 such as sockets, elbows, T, Y, crosses, etc. FIG. 3 shows an elbow.

  On the other hand, in the piping system for water supply (water supply, miscellaneous water), as a countermeasure against red water, as shown in FIG. 4, at least the inner surface and the outer surface of the steel pipe 41 are resin (polyethylene resin or hard polyvinyl chloride resin) lining. A lining steel pipe (polyethylene powder lining steel pipe for water supply, hard vinyl chloride lining steel pipe for water supply) 4 in which a layer 42 is formed, together with a conventional pipe end anticorrosion joint (for example, Patent Document 2) 200, as shown in FIG. It is used.

  A conventional pipe end anti-corrosion joint 200 includes a joint body 201 which is a screw-type malleable cast iron pipe joint and a resin core 2 which performs a pipe end anti-corrosion function.

  The joint body 201 has an inner thread portion into which an outer thread portion (male thread portion: taper thread portion for pipe) 143 formed on the outer periphery of the end portion of the lining steel pipe 4 is screwed into the outer periphery of the end portion of the joint body 201. A joint in which at least the inner threaded portion 11 is not formed among the inner surface and the outer surface of the joint body 201 in which the female threaded portion: taper threaded portion for pipe 11 is formed and the inner threaded portion 11 is not formed. A resin (epoxy resin) lining layer 3 is formed on the unthreaded portion 12 on the inner surface of the main body 201.

  The core 2 is made of polyethylene resin, and an annular flange 22 is integrally connected to an end of a cylindrical body portion 21 inserted and inserted into an end of the lining steel pipe 4. Is formed with an external thread portion (male thread portion: taper thread portion for pipe) 23 that is screwed into the internal thread portion 11 of the joint body 201 and is formed at an intermediate portion in the axial direction of the cylindrical body portion 21. Is fitted in the annular groove 24b, and an annular groove 24b formed adjacent to the inner side of the lip 24a. A seal portion 24 is provided which is composed of an O-ring 24 c and seals between the core 2 and the lining steel pipe 4 by elastically pressing the lip portion 24 against the resin lining layer 42 on the inner surface of the lining steel pipe 4.

  The annular end surface 22a of the flange portion 22 of the core 2 is subjected to a modification process for converting the molecular structure of the surface into an easily adhesive property by a plasma jet projected toward the annular end surface 22a.

  In the core 2, the outer threaded portion 23 of the flange portion 22 is screwed into the inner threaded portion 11 of the end portion of the joint body 201, and the annular end surface 22 a of the flange portion 22 is at the end portion of the resin lining layer 3 of the joint body 201. It is screwed in until it comes into contact, and is mounted in the end portion of the joint body 201 in a state in which the outer thread portion 23 of the flange portion 22 is engaged with the inner side of the inner thread portion 11 at the end portion of the joint body 201. In this way, the core 2 mounted in the end of the joint body 201 is an epoxy coated on the intersection of the annular end surface 22a of the flange 22 and the resin lining layer 3 of the joint body 201 as shown in FIG. The joint 9 is bonded and fixed to the joint body 201 by a system adhesive 9. Here, the core 2 is made of polyethylene resin, but the molecular structure of the surface of the annular end surface 22a, which is an adhesive surface thereof, is converted to easy adhesion. It can be easily and strongly bonded and fixed, and the sealing property of the connecting portion between the core 2 and the joint main body 1 can be secured, and the two 2 and 1 can be integrated. That is, the pipe end anticorrosion joint 200 is assembled.

  In order to connect the end portion of the lining steel pipe 4 to the end portion of the pipe end anticorrosion joint 200, first, an anticorrosive sealant for clean water is applied to the outer thread portion and the end surface 44 of the lining steel pipe 4, or the lining steel pipe 4 is used. A seal tape is wound around the outer screw portion 4 and an anticorrosive sealant for clean water is applied to the end surface 44. Then, it can carry out only by screwing the external thread part 43 of the edge part of the lining steel pipe 4 to the internal thread part 11 of the edge part of the coupling main body 201, and screwing.

  In the connected state, the lip portion 24a of the seal portion 24 provided on the cylindrical body portion 21 of the core 2 is elastically pressed to the resin lining layer 42 on the inner surface of the lining steel pipe 4, and the lining steel pipe 4 and The sealing property (airtightness, watertightness) of the connecting portion with the core 2 is ensured. In addition, since the core 2 and the joint body 1 are strongly bonded and fixed through the adhesive 9, the core 2 rotates together when the lining steel pipe 4 is screwed to the joint body 1, and the adhesive 9 is peeled off. Therefore, the sealing performance of the connecting portion between the core 2 and the joint body 1 can be maintained as it is.

  In the connected state, there is no fear that water will enter the end surface 44 of the lining steel pipe 41 from any of the connection places between the core 2 and the joint body 1 and the connection places between the lining steel pipe 4 and the core 2, and rust will be generated. The predetermined pipe end anticorrosion performance can be surely exhibited. There are many types of pipe end anticorrosion joints 200 such as sockets, elbows, T, Y, and crosses. FIG. 4 shows an elbow.

  The conventional pipe end anti-corrosion joint 200 can prevent the occurrence of rust and red water (rust) on the end surface (iron exposed part) of the lining steel pipe 4, and a piping system for water supply (water supply, miscellaneous water) (lining steel pipe 4) Can be suitably used.

However, in the conventional pipe end anticorrosion joint 200, unlike the precoat joint 100, when connecting the lining steel pipe 41, it is troublesome to apply the liquid sealant to the outer threaded portion 43 of the lining steel pipe 41 or wind the seal tape. It takes.

JP-A-6-25605 JP 2001-146987 A

In recent years, also in piping systems for water supply (water supply, miscellaneous water), reduction of construction time has been demanded in the same manner as piping systems for water (excluding drinking water) and air. In the conventional pipe end anti-corrosion joint 200 as well as the pre-coated joint 100, the joint main body 201 is provided for the purpose of saving the trouble of applying the liquid sealant to the outer threaded portion 43 of the lining steel pipe 41 and winding the seal tape. A seal made of a fluororesin such as PTFE over the entire length of the inner screw portion 11 into which the outer screw portion 43 formed on the outer periphery of the end portion of the lining steel pipe 4 is screwed. It is conceivable that the sealant 110 is formed on the entire surface of the inner thread portion 11 of the joint body 201 by baking the coating agent.

  However, the conventional pipe end anticorrosion joint 200 is originally limited to a short screw length of the outer threaded portion 23 of the core 2, and when the end of the lining steel pipe 4 is screwed into the end of the joint body 201, Such a load in the screwing direction is difficult to be received by the inner screw portion 11 of the joint body 201. In addition, when the above-described configuration is adopted for the conventional pipe end anticorrosion joint 200, the surface of the inner thread portion 11 of the joint body 201 to which the core 2 is attached is also used as a lubricant by the seal layer 110 (precoat). Since the friction between the thread surface of the inner threaded portion 11 of the joint body 201 and the threaded surface of the outer threaded portion 23 of the core 2 is extremely small, the load in the screwing direction applied to the core 2 As a result, even if the end of the lining steel pipe 4 is properly screwed into the end of the joint body 201, the annular end surface 22a of the flange 22 The load applied to the adhesive 9 applied to the intersection of the joint body 201 with the resin lining layer 3 is increased.

  The conventional pipe end anticorrosion joint 200 is modified to process the surface of the annular end surface 22a by projecting a plasma jet toward the annular end surface 22a of the flange 22 of the core 2 made of polyethylene resin. The adhesive 9 is applied to the intersection between the annular end surface 22a of the flange 22 and the resin lining layer 3 of the joint body 201, and the adhesive 9 is also built up so that the joint body 201 and the core 2 are integrated. Although the adhesive force between the joint body 201 and the core 2 is reinforced by bonding and fixing, the adhesive force obtained by the adhesion is when the end portion of the lining steel pipe 4 is screwed into the end portion of the joint body 201. Then, cohesive failure or adhesive failure occurs, and the core 2 is detached from the joint body 201 and pushed into the back side of the joint body 201, so that the pipe end anticorrosion function carried by the core 2 may be lost.

  That is, as long as the above problems are not solved, a pipe end anticorrosion joint that can save the trouble of applying a liquid sealant to the outer threaded portion of the lining steel pipe and winding the seal tape is realized and provided for practical use. I can't.

  Therefore, the present invention has been made in view of the above problems, and its purpose is to provide a joint body and a joint body with a new adhesive fixing structure that can be obtained by further strengthening the adhesive force between the joint body and the core. A pipe end anti-corrosion joint that can save and eliminate the trouble of winding a sealant or seal tape during construction by securely bonding the core and a pipe end anti-corrosion joint, and a method for manufacturing the same. It is to provide.

The first means of the present invention for achieving the above object has an inner threaded portion 11 into which an outer threaded portion 43 formed at the end of the lining steel pipe 4 having a resin lining layer 42 formed on the inner surface is screwed. In addition, a metal joint body 301 in which the resin lining layer 3 is formed on the inner threadless portion 12 and an end portion of the cylindrical body portion 21 inserted into the end portion of the lining steel pipe 4 are annular. The flange portion 22 is continuously provided, and an outer thread portion 23 to be screwed to the inner thread portion 11 of the joint body 301 is provided on the outer periphery of the flange portion 22, and the cylindrical body portion 21 is provided. Is a pipe end anticorrosion joint 300 provided with a resin core 2 provided with a seal portion 24 elastically pressed against the resin lining layer 42 of the lining steel pipe 4, the joint body 301 on the inner threaded portion 11, At least, when the core 2 is assembled to the joint body 301, the sealant 10 made of fluororesin is baked and coated except for the range L2 in which the outer screw portion 23 of the core 2 is screwed. The inner thread portion 11 of the joint body 301 is formed with a seal layer 110 made of the fluororesin sealant 10 and a non-painted portion L2 where the seal layer 110 is not formed. The non-painted portion L2 The joint body 301 and the core 2 are integrally bonded and fixed by applying the adhesive 9 to the pipe, and the adhesive 9 is also applied to the exposed portion of the non-coating portion L2. An end anticorrosion joint is provided.

The second means of the present invention is a method for manufacturing a pipe end anti-corrosion joint provided by the first means, wherein the joint body 301b after the resin lining layer 3 is formed or the resin lining layer 3 is formed. The fluororesin except for a range L2 in which the outer threaded portion 23 of the core 2 is screwed to the inner threaded portion 11 of the joint body 301a before being joined at least when the core 2 is assembled to the joint body 301. The seal layer 110 made of the fluororesin sealant 10 and the seal layer 110 are not formed on the inner threaded portion 11 of the joint body 301 by baking and painting the sealant 10 made of the above. The coating process (C) for forming the non-coating portion L2, and the non-coating of the joint body 301d as a finished product after the resin lining layer 3, the sealing layer 110, and the non-coating portion L2 are formed. The adhesive 9 to the part L2 is applied includes a core mounting step of bonding and fixing together (d) a fitting body 301d and the core 2, in the core mounting step (d) of the non-coated part L2 adhesive 9 to the exposed portion to provide a method for producing a pipe end anticorrosion joint, characterized in Rukoto applied.

  According to the present invention, a seal layer made of a fluororesin sealant can be formed on the inner thread portion of the joint body, and a non-painted portion in which the seal layer of the inner thread portion of the joint body is not formed; Adhesive fixing structure between the joint body and core of the pipe end anticorrosion joint by the joint fixing structure of the joint body and core, which is bonded and fixed to the male thread of the core with an adhesive. Since the force can be further strengthened, it is possible to save the trouble of winding a sealing agent or a sealing tape at the time of construction, and the pipe end anticorrosion joint that can reliably hold and exhibit the pipe end anticorrosion function, and its A manufacturing method can be provided.

Sectional drawing which shows the structure of the pipe end anti-corrosion joint concerning embodiment of this invention Explanatory drawing which shows the manufacturing method of the pipe end anti-corrosion joint concerning embodiment of this invention Sectional view showing the structure of a pre-coated joint Sectional view showing the structure of a conventional pipe end anticorrosion joint

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view showing a structure of a pipe end anticorrosion joint according to an embodiment of the present invention, and FIG. 2 is an explanatory view showing a method for manufacturing the pipe end anticorrosion joint according to an embodiment of the present invention. There are many types of pipe end anticorrosion joints 300 of the present embodiment, such as sockets, elbows, T, Y, and crosses. FIGS. 1 and 2 show elbows.

  As is apparent from FIGS. 1 and 4, the basic structure of the pipe end anticorrosion joint 300 of the present embodiment shown in FIG. 1 is the same as the conventional pipe end anticorrosion joint 200 shown in FIG. Are given the same reference numerals and their detailed description is omitted.

  As shown in FIG. 1, the pipe end anticorrosion joint 300 according to this embodiment includes an inner thread portion in which an outer thread portion 43 formed at an end portion of a lining steel pipe 4 having a resin lining layer 42 formed on an inner surface thereof is screwed. 11 and a joint body 301 made of metal in which the resin lining layer 3 is formed on the unthreaded portion 12 on the inner surface and the end of the cylindrical body portion 21 inserted into the end portion of the lining steel pipe 4 An annular flange portion 22 is continuously provided in the portion, and an outer thread portion 23 that is screwed into the inner thread portion 11 of the joint body 301 is provided on the outer periphery of the flange portion 22, and the cylindrical body portion 21 is provided. Includes a resin core 2 provided with a seal portion 24 that is elastically pressed against the resin lining layer 42 of the lining steel pipe 4.

  Further, a range L2 in which the outer threaded portion 23 of the core 2 is screwed to the inner threaded portion 11 of the joint main body 301 at least when the core 2 is assembled to the joint main body 301 (particularly, (c) in FIG. The seal layer 110 made of the fluororesin sealant 10 and the seal layer 110 are formed on the inner threaded portion 11 of the joint body 301 by baking and coating the fluororesin sealant 10 except for A non-painted portion L2 that is not formed is formed, and the joint body 301 and the core 2 are integrally bonded and fixed by applying an adhesive 9 to the non-painted portion L2.

  In the core 2, the outer threaded portion 23 of the flange portion 22 is screwed into the inner threaded portion 11 of the end portion of the joint body 201, and the annular end surface 22 a of the flange portion 22 is the end portion of the resin lining layer 3 of the joint body 201. The outer threaded portion 23 of the flange portion 22 is fitted in the end of the joint body 201 in a state where the outer threaded portion 23 of the flange portion 22 is engaged with the inner end of the inner threaded portion 11. Here, in the pipe end anti-corrosion joint 300, the nominal range is also defined. However, according to the nominal range and the shape and dimensions of the end of the joint for each nominal size, the outer threaded portion of the flange portion 22 of the core 2 The screw length of 23 falls within the range of 2.5 mm or more and 4.00 mm or less depending on the size, and when converted into the number of ridges, it falls within the range of 1.4 or more and 1.73 or less. In consideration of coating variation, the range is from 1.5 to 4 peaks. This is because the outer threaded portion 23 of the flange portion 22 of the core 2 does not peel off the seal layer 110 formed on the inner threaded portion 11 of the joint body 301, so that the non-painted portion L2 is lengthened and thereby peeled off. This is because the sealed layer 110 is desirable without adversely affecting the adhesion of the core 2. Here, for example, the number of threads of the outer threaded portion 23 of the flange portion 22 of the core 2 is 1.5 and the number of uncoated portions L2 of the inner threaded portion 11 at the end of the joint body 201 is 2.5. Then, a metal exposed portion corresponding to approximately one thread (2.5 threads-1.5 threads = 1 thread) is formed on the inner thread part 11 at the end of the joint body 201. Since 9 is applied also there, it does not rust from there.

  As the sealant 10 made of a fluororesin, for example, a precoat sealant “Eight Seal (registered trademark)” manufactured by Taihei Kasei Co., Ltd. can be used.

  Next, a manufacturing method of the pipe end anticorrosion joint 300 of the present embodiment will be described with reference to FIGS.

(A) Casting process In this process, after manufacturing the metal part 301a (excluding the internal thread part 11) of the joint body 301, the internal thread part 11 is applied to the inner surface of the end part of the metal part 301 of the joint body 301 obtained. Form.
(A) Inner surface resin lining step In this step, the resin lining layer 3 is formed by powder baking coating of epoxy resin on the unthreaded portion 12 of the inner surface of the metal portion 301a of the joint body 301 obtained in (A). In the baking coating, the epoxy resin powder sprayed from the nozzle of the coating apparatus is applied to the unthreaded portion 12 on the inner surface of the metal portion 301a (however, the epoxy resin powder is applied to the inner screw portion 11 on the inner surface of the metal portion 301a). The body is not applied.) After complete drying, a baking process is performed at a predetermined temperature for a predetermined time. For example, a baking process is performed at 200 ° C. for 40 minutes. Further, when painting, a masking tape may be used in order to obtain the dimensional accuracy of painting while not painting other than the necessary portions. This point is the same in the next process.
(C) Painting step In this step, at least the joint main body 301 has the inner threaded portion 11 of the metal part 301b (metal part 301b after the resin lining layer 3 is formed) of the joint main body 301 obtained in (a). The sealant 10 made of fluorine resin is baked and coated except for the range L2 in which the external thread portion 23 of the core 2 is screwed when the core 2 is assembled. The seal layer 110 is formed, and the non-coating portion L2 where the seal layer 110 is not formed is formed. That is, when the total screw length of the inner screw portion 11 is L, and the range L2 in which the outer screw portion 23 of the core 2 is screwed when the core 2 is assembled to the joint body 301, the coating portion L1 is L-L2. The seal layer 110 is formed in the range of the painted portion L1. In the baking coating, the sealant 10 sprayed from the nozzle 5 of the coating apparatus is applied to the inner threaded portion 11 of the metal portion 301b (however, when the core 2 is assembled to the joint body 301, the outer thread of the core 2). The sealant 10 is not applied to the range L2 in which the portion 23 is screwed.) After complete drying, a baking process is performed at a predetermined temperature for a predetermined time. For example, a baking process is performed at 200 ° C. for 40 minutes.
(D) Core mounting process (joint assembly process)
In this process, the finished product 301d of the joint body 301 obtained in (c), that is, the non-painted portion of the metal portion 301d of the joint body 301 in which the resin lining layer 3, the seal layer 110, and the non-painted portion L2 are formed. Adhesive 9 is applied to L2, and joint body 301d and core 2 are bonded and fixed together. As described above, in the core 2, the outer threaded portion 23 of the flange portion 22 is screwed into the inner threaded portion 11 of the end portion of the joint body 201, and the annular end surface 22 a of the flange portion 22 is the resin lining layer 3 of the joint body 201. The outer threaded portion 23 of the flange portion 22 is fitted into the end of the inner threaded portion 11 at the end of the joint body 201 and is fitted into the end of the joint body 201. The The core 2 is manufactured by injection molding of a polyethylene resin separately from the joint body 301.

  In the manufacturing method of the pipe end anticorrosion joint 300 according to the present embodiment, the steps (A) to (D) are performed in that order, and the pipe end anticorrosion joint 300 shown in FIG. 1 is manufactured. In addition, (b) the inner surface resin lining process was performed prior to (c) the coating process, but because the temperatures of the baking treatment in both processes are substantially the same, conversely, (b) the inner surface resin lining process. Although it is possible to perform the (c) coating process first, it is desirable to perform the (a) inner surface resin lining process before the (c) coating process in the following points. That is, (a) if the coating step is performed prior to the inner surface resin lining step, the sealing layer 110 made of the fluororesin sealing agent 10 is softer than the epoxy resin lining layer 3. B) Use care when handling the inner resin lining process. (C) Even if the inner resin lining process is performed prior to the coating process, the epoxy resin resin lining layer 3 is hard, so when holding the fluororesin sealant 10 in hand, hold it by hand. There is no problem.

As described above, the manufacturing method of the pipe end anticorrosion joint 300 according to the present embodiment is the joint body 301b after the resin lining layer 3 is formed or the inner thread portion 11 of the joint body 301a before the resin lining layer 3 is formed. In addition, at least when the core 2 is assembled to the joint body 301, the fluororesin is baked and coated with the sealant 10 made of the fluororesin except for the range L2 in which the external thread portion 23 of the core 2 is screwed. A coating step (c) for forming a seal layer 110 made of the sealant 10 made of the resin and forming a non-coating portion L2 in which the seal layer 110 is not formed, the resin lining layer 3, the seal layer 110, and the non-coating A core mounting process (D) in which the adhesive 9 is applied to the unpainted portion L2 of the joint body 301d as a finished product after the portion L2 is formed, and the joint body 301d and the core 2 are bonded and fixed together. Including the door, to produce a pipe end anticorrosive fitting 300 shown in FIG. In the core mounting step (D), the adhesive 9 is also applied to the exposed portion of the non-painted portion L2.

As described above, according to the pipe end anti-corrosion joint 300 of the present embodiment and the manufacturing method thereof, the water supply (water supply, miscellaneous water) piping system is similar to the water (excluding drinking water) and air piping systems. In order to shorten the construction time, in the same manner as the pre-coated joint 100, the joint body 301 is provided with the purpose of eliminating the trouble of applying the liquid sealant to the outer threaded portion 43 of the lining steel pipe 41 and winding the seal tape. A seal layer 110 made of a fluororesin sealant 10 is formed on the inner thread portion 11, but the seal layer 110 is not formed on the entire surface of the inner thread portion 111 like the precoat joint 100. However, at least when the core 2 is assembled to the joint body 301, the seal layer 110 is formed in the joint body 301 because the outer thread portion 23 of the core 2 is formed to exclude the range L 2. The friction between the thread surface of the threaded portion 11 and the thread surface of the external thread portion 23 of the core 2 is not extremely reduced, and the end portion of the lining steel pipe 4 is screwed into the end portion of the joint body 301. Even in this case, the load in the screwing direction applied to the core 2 is received by the inner thread portion 11 of the joint body 201 as in the conventional pipe end anticorrosion joint 200 in which the seal layer 110 is not formed on the inner thread portion 11. Will be able to.

  In addition, according to the pipe end anticorrosion joint 300 of the present embodiment and the manufacturing method thereof, the outer thread portion 23 of the core 2 and the inner thread of the joint body 301 that are engaged with each other when the core 2 is assembled to the joint body 301. Since the part 11 is bonded and fixed by the adhesive 9, the two adherend surfaces to be bonded are constituted by screw surfaces, and the annular end surface 22 a of the flange part 22 of the core 2 and the resin lining layer 3 of the joint body 201 Compared to the adhesive fixing structure of the joint body 201 and the core 2 of the conventional pipe end anticorrosion joint 200 in which the intersection is bonded and fixed by the adhesive 9, a much larger bonding area can be secured and strong bonding is achieved. It will be possible to secure power.

  Moreover, according to the pipe end anticorrosion joint 300 and the manufacturing method thereof according to the present embodiment, the material of the adherend surface on the core 2 side is an adhesive fixing structure between the joint body 201 of the conventional pipe end anticorrosion joint 200 and the core 2. Is the same polyethylene resin, but the joint body 301 side is made of metal, and has a stronger adhesive strength than the joint fixing structure of the joint body 201 and the core 2 of the conventional pipe end anticorrosion joint 200 which is an epoxy resin. It will be possible to secure.

  Then, according to the pipe end anticorrosion joint 300 and the manufacturing method thereof according to the present embodiment, even if the core 2 is made of polyethylene resin, the coated surface on the core 2 side is converted to easy adhesion. Therefore, a strong and sufficient adhesive force can be secured as compared with the conventional adhesive fixing structure between the joint body 201 and the core 2 of the pipe end anticorrosion joint 200 without performing the surface treatment for the joint body 301. When the end portion of the lining steel pipe 4 is properly screwed into the end portion or excessively screwed, it causes cohesive failure or adhesion failure, and the core 2 is detached from the joint body 301 and the inner part of the joint body 301 is removed. It is possible to solve the problem that the pipe end anticorrosion function carried by the core 2 may be lost.

Therefore, according to the pipe end anticorrosion joint 300 of this embodiment and the manufacturing method thereof, the seal layer 110 made of the fluororesin sealant 10 can be formed on the inner thread portion 11 of the joint body 301, and bonded structure between the joint body 301 and the core 2 which is bonded and fixed with an adhesive 9 and the external thread portion 2 3 of the sealing layer 110 is not formed unpainted portion L2 and the core 2 of the internal thread portion 11 of the joint body 301 As a result, the adhesive strength between the joint body 301 and the core 2 can be further enhanced as compared with the adhesive fixing structure between the joint body 201 and the core 2 of the conventional pipe end anticorrosion joint 200. It is possible to provide a pipe end anticorrosion joint that can save the trouble of winding the seal tape and can reliably hold and exhibit the pipe end anticorrosion function, and a method for manufacturing the same.

Further, the pipe end anticorrosive fitting 300 of this embodiment, and according to the manufacturing method thereof, an external thread portion 2 3 unpainted portion L2 and the core 2 that the sealing layer 110 of the internal thread portion 11 is not formed in the joint body 301 And the joint body 301 and the core 2 are bonded and fixed together with the adhesive 9, so that the entire gap between the joint body 301 and the core 2 is closed with the adhesive 9. Compared to the conventional adhesive fixing structure of the joint body 201 and the core 2 of the pipe end anticorrosion joint 200 that only blocks the gap entrance of the connection place, it is possible to ensure and maintain a high sealing performance at the connection place. Become.

As shown in FIG. 1, in the pipe end anti-corrosion joint 300 of this embodiment, the joint fixing structure of the joint main body 201 and the core 2 of the conventional pipe end anti-corrosion joint 200, that is, the annular end surface 22a of the flange 22 and the joint main body. The adhesive 9 applied in a piled-up manner at the intersection of the 201 with the resin lining layer 3 is used as it is, but this is merely an auxiliary meaning to increase the adhesive force between the joint body 301 and the core 2. adopted and, be removed, the fitting body for bonding and fixing the uncoated section L2 and the outer threaded part 2 3 of the core 2 the sealing layer 110 of the internal thread portion 11 is not formed in the joint main body 301 with an adhesive 9 The adhesive force between the joint main body 301 and the core 2 can be obtained as necessary and sufficient only by the adhesive fixing structure between the 301 and the core 2. The same applies to the modification of the surface of the annular end surface 22a by projecting a plasma jet toward the annular end surface 22a of the flange portion 22 of the core 2 made of polyethylene resin. fitting body 301 by bonding and fixing structure between the joint body 301 and the core 2 to adhere the sealing layer 110 of the internal thread portion 11 is not formed and a non-coated portion L2 and the outer threaded portion 2 3 of the core 2 with the adhesive 9 and as a further reinforcing means adhesion of the core 2 may be performed with respect to the outer threaded portion 2 3 of the surface of the core 2.

  As mentioned above, although this embodiment demonstrated the preferable embodiment of this invention by the pipe end anti-corrosion joint for inner surface resin-lined steel pipes, this invention is not limited to it but various deformation | transformation implementation is performed within the range which does not deviate from the summary. can do. For example, it can also be applied to pipe end anticorrosion joints for inner and outer resin lined steel pipes.

2 Core 3 Resin Lining Layer 4 Lining Steel Pipe 9 Adhesive 10 Sealing Agent Made of Fluorine Resin 11 Internal Threaded Part 12 Unthreaded Part 21 Cylindrical Body 22 Gutter 23 External Threaded Part 24 Sealed Part 42 Resin Lining Layer 43 External Thread Part 110 Seal layer 300 Pipe end anticorrosion joint 301 Joint body 301a Metal part 301b Metal part 301d Metal part L Total thread length of internal thread part L1 Painting range (painted part: seal layer)
L2 Non-coating range (non-coating part: adhesive layer)
(C) Painting process (d) Core installation process

Claims (2)

A resin lining layer is formed on the inner surface.The outer thread portion formed on the end portion of the lining steel pipe has an inner thread portion that is screwed together, and a resin lining layer is formed on the unthreaded portion of the inner surface. An annular flange is connected to the end of the tubular body inserted into the end of the lining steel pipe and the end of the joint body. A resin core provided with an external thread portion to be screwed to the screw portion, and a seal portion elastically pressed against the resin lining layer of the lining steel pipe on the cylindrical body portion; A pipe end anti-corrosion joint, except that at least the outer thread portion of the core when the core is assembled to the inner thread portion of the joint body is screwed together. Fluorine resin sealant is baked and painted As a result, a seal layer made of the fluororesin sealant and a non-painted portion where the seal layer is not formed are formed on the inner thread portion of the joint body, and the non-painted portion is bonded to the non-painted portion. A pipe end anticorrosive joint, wherein the joint body and the core are integrally bonded and fixed by applying an agent, and the adhesive is also applied to an exposed portion of the non-painted portion . It is a manufacturing method of the pipe end anti-corrosion joint according to claim 1, wherein at least the inner thread portion of the joint body after the resin lining layer is formed or the joint body before the resin lining layer is formed, When the core is assembled to the joint body, the fluororesin sealant is baked and coated except for the area where the outer threaded portion of the core is screwed together. As a finished product after forming the sealing layer and forming the non-coating portion where the sealing layer is not formed, and the resin lining layer, the sealing layer, and the non-coating portion are formed. the adhesive is applied to the uncoated portion of the joint body includes a core mounting step of bonding and fixing the fitting body and the core integrally, the in the exposed portion of the non-coated part in the core mounting process Method for producing a wear agent is applied pipe end anticorrosive joint according to claim Rukoto.

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