JP2005351428A - Corrosion prevention structure of pipe end face - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a corrosion prevention structure of a pipe end face capable of easily and speedily performing work for preventing corrosion of a cut face of a metallic pipe cut and exposing a surface of the end face and forming an outer peripheral protruding part at the outer periphery of this pipe. <P>SOLUTION: An annular corrosion prevention member 11 composed of an elastic member having a covered part 13a for preventing corrosion by curving and covering a metallic part 3c, an end face corrosion prevention part 13 formed on an inner side of the covered part 13a and having a pressing ring part 13b capable of pressing a protection layer part 3d, and an outer peripheral face contact part 14 coming into contact with an outer peripheral face 3e is mounted in an end part of the pipe exposing the metallic part 3c and the protection layer part 3d of the cut face 3b by cutting the metallic pipe having mortar lining 6 on an inner face. An annular insertion port ring 12 composed of a metallic member having a contact part pressing part 15 forming an insertion port protruding part 4 at the outer periphery of the pipe and provided from the outer peripheral face 3e to the cut face 3b to press the outer peripheral face contact part 14 against the outer peripheral face 3e and a covered part pressing part 16 for pressing the covered part 13a against a cut face 3b side is externally fitted. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pipe end face anticorrosion structure.

2. Description of the Related Art In recent years, in pipes such as waterworks, replacement of a pipe line that does not have a detachment prevention function and an expansion / contraction function at a joint part to a pipe line that has a detachment prevention function and an expansion / contraction function at a joint part has been performed.
As shown in FIG. 5, for example, a pipe joint having a separation preventing function and an expansion / contraction function (hereinafter referred to as an earthquake resistant function) is provided with a lock ring 2 in a centered state on the inner periphery of the receiving port 1. When the insertion port 3 having the insertion projection 4 on the outer periphery of the end is inserted into the mouth 1 and the insertion port 3 is about to come out of the receiving port 1, the insertion projection 4 of the insertion port 3 is locked. The insertion port 3 is prevented from being detached by moving to the position 2 and engaging with the lock ring 2, and when the expansion / contraction force acts on the joint portion, the insertion projection 4 is connected to the lock ring 2 and the receiving port. It can be expanded and contracted by moving between the rear end surface 5 of 1. A tapered surface 4 a is formed on the outer periphery on the distal end side of the insertion port protrusion 4, and when the insertion port 3 is inserted into the receiving port 1, the insertion port protrusion 4 is disposed in the receiving port 1. The diameter of the lock ring 2 and the like can be easily expanded. Moreover, for example, a mortar lining 6 is formed on the inner surface of each of the receiving port 1 and the insertion port 3 as a protective layer for protecting the inner surface of the tube.

  On the other hand, when laying a pipeline having such an earthquake-resistant function, the pipe may be cut to a predetermined length on the piping construction site due to the length of the pipeline to be laid. For example, as shown in FIG. 6, the insertion port 3 is cut at a predetermined cutting position 7, and a tube (hereinafter referred to as a remaining tube) 3 a that does not have the insertion port protrusion 4 is left. In this case, in order to configure a pipe line using the remaining pipe 3a, it is necessary to form a new insertion projection 4 at the end of the remaining pipe 3a as shown by the phantom line in the figure. is there. In addition, when the remaining pipe 3a is a metal pipe such as a ductile cast iron pipe, the surface of the pipe is coated for anticorrosion, but when the pipe is cut, the cut surface that is the cut end Since the metal background is exposed at 3b, it is necessary to apply anticorrosion treatment to the cut surface 3b.

Under such circumstances, each of Patent Documents 1 to 3 describes a technique for performing anticorrosion treatment on the cut surface 3b of the tube. Specifically, Patent Document 1 describes a technique for preventing corrosion on a cut surface by attaching a corrosion prevention member from the inside of the tube to an end portion on the cut surface side of the tube. A technique is described in which a heat-shrinkable tube is covered from the outer peripheral surface to the cut surface, and the heat-shrinkable tube is shrunk to prevent the cut surface from corrosion. Furthermore, Patent Document 3 describes a technique for brushing a corrosion-resistant paint on a cut surface of a tube.
Japanese Utility Model Publication No. 5-3789 JP 2001-12684 A Japanese Patent Laid-Open No. 5-287224

  However, according to the technique described in Patent Document 1, since only the anticorrosion member is attached to the end portion on the cut surface side of the tube from the inside of the tube, for example, an annular groove is formed on the outer periphery of the remaining tube. However, when the insertion ring is fitted to the annular groove to form the insertion projection, the anticorrosion treatment cannot be applied to the annular groove from which the processed surface is exposed.

Moreover, according to the technique described in Patent Document 2, a heat source for heating the heat-shrinkable tube is required, and the work in the water field becomes difficult.
Furthermore, according to the technique described in Patent Document 3, for example, in cold weather, it takes time until the anticorrosion paint dries, and is not suitable for work in a water field.

  Accordingly, the present invention solves such a problem, and performs anticorrosion treatment on the cut surface of the metal tube that is cut and the ground surface of the end surface is exposed, and forms an outer peripheral protrusion on the outer periphery of the end portion of the tube. It is an object of the present invention to provide a pipe end face anticorrosion structure capable of easily and quickly performing the work to be performed.

  In order to solve the above-mentioned problems, the invention according to claim 1 is characterized in that a metal tube having a protective layer for corrosion protection is cut on the inner surface, and the background of the metal portion and the protective layer portion on the cut surface are exposed. A coating portion that is formed in a curved shape and covers the metal portion of the cut surface to prevent corrosion, and a pressure that is formed on the inner portion of the tube in the radial direction of the tube and that can press the protective layer portion An end surface anticorrosion portion having a portion, and an outer peripheral surface contact portion that is formed from the end surface anticorrosion portion to the outer peripheral surface of the end portion of the tube and contacts the outer peripheral surface of the end portion of the tube, and is annularly formed by an elastic member The formed first member is mounted, forms an outer peripheral protrusion at the outer periphery of the end of the tube, and is provided from the outer peripheral surface of the end of the tube to a position facing the cutting surface of the tube, The outer peripheral surface contact portion is the end of the tube. Formed in an annular shape by a metal member while having a contact portion pressing portion that presses inward in the radial direction of the tube on the outer peripheral surface, and a covering portion pressing portion that presses against the cut surface side of the tube while elastically deforming the covering portion The second member is fitted on the outer periphery of the end of the tube, the covering portion is pressed by the covering portion pressing portion and elastically deformed, and the pressing portion causes the protective layer to be elastically deformed. The part is pressed.

  According to such a configuration, the covering portion in the end surface anticorrosion portion of the first member can cover the metal portion in the cut surface of the tube, and the pressing portion in the end surface anticorrosion portion can press the protective layer portion. Then, the covering portion pressing portion in the second member presses the protective layer portion by pressing against the cut surface side while elastically deforming the covering portion, and the protective layer portion is pressed by the pressing portion. Further, the contact portion pressing portion of the second member presses the outer peripheral surface contact portion of the first member to the outer peripheral surface of the end portion of the tube inward in the radial direction of the tube. The outer peripheral contact portion can seal the outer peripheral surface of the end of the tube. Thereby, the state in which the covering portion covers the metal portion on the cut surface, that is, the state in which the covering portion is anticorrosive to the metal portion can be maintained, and a reliable anticorrosion treatment can be applied to the metal portion. Can be applied. Further, the covering portion is formed to be curved to cover the metal portion, and the pressing portion is in contact with the protective layer portion, for example, the covering portion is not formed to be curved, and the covering portion is not formed. Compared with the case where it directly contacts the metal part, the pressing force from the covering portion pressing portion is prevented from being distributed to the covering portion and the pressing portion, and the pressing force is applied to the pressing portion with priority. Therefore, the pressing portion can press the protective layer portion with a stronger force. Further, the outer peripheral surface contact portion is pressed inward in the radial direction of the tube by the contact portion pressing portion to the outer peripheral surface of the end portion of the tube, so that the first in a state of being attached to the end portion of the tube. One member can be stabilized. Thereby, it can prevent that this 1st member falls out from the edge part of the said pipe | tube. Furthermore, since the second member forms an outer peripheral protrusion on the outer periphery of the end portion of the tube, the outer peripheral protrusion can be easily and quickly formed on the outer periphery of the end portion of the tube.

  The invention according to claim 2 is attached to the end portion of the tube where the ground of the metal portion and the protective layer portion of the cut surface of the metal tube having the anticorrosive protective layer on the inner surface are exposed, and an elastic member A pipe end face anticorrosion member formed in an annular shape by a curved portion that covers the metal portion of the cut surface and prevents corrosion, and is formed on the radially inner portion of the cover portion. An end surface anticorrosion portion having a pressing portion capable of pressing the protective layer portion, and an outer peripheral surface contact portion formed from the end surface anticorrosion portion to the outer peripheral surface of the end portion of the tube and in contact with the outer peripheral surface of the end portion of the tube; It is what has.

  As described above, according to the present invention, the cut surface of the metal tube that is cut and the ground surface of the end surface is exposed can be reliably subjected to anticorrosion treatment, and the outer peripheral protrusion is provided on the outer periphery of the end portion of the tube. It can be formed easily and quickly.

  An embodiment of the pipe end face anticorrosion structure of the present invention will be described with reference to FIGS. Hereinafter, a case where the metal pipe is a ductile cast iron pipe (hereinafter referred to as a pipe) will be described. The surface of the tube is previously painted for anticorrosion. In addition, about the same location as the location demonstrated using FIG.5 and FIG.6, the detailed description is abbreviate | omitted by attaching | subjecting the same code | symbol as the code | symbol used in FIG.5 and FIG.6.

  As shown in FIG. 1, the pipe end face anticorrosion structure of the present embodiment is such that a pipe having an anticorrosive mortar lining 6 on its inner surface is cut at a pipe construction site, and a metal portion 3c on the cut surface 3b of the remaining pipe 3a. At the end where the surface of the metal and the protective layer portion 3d are exposed, an anticorrosion member 11 on the end surface of the tube is attached as a first member that is formed in an annular shape by an elastic member and prevents the metal portion 3c. An insertion ring 12 as a second member formed in a ring shape by a metal member, for example, a ductile cast iron member, is fitted on the outer periphery of the end portion of the remaining pipe 3a so as to cover the anticorrosion member 11. Configured. An annular groove 18 is formed on the outer periphery of the remaining tube 3a.

  As shown in FIG. 1 and FIG. 2 (a), the anticorrosion member 11 on the pipe end surface is curved with respect to the cut surface 3b and is formed in an arc shape that swells with respect to the cut surface 3b, for example. Cover part 13a for covering and preventing metal part 3c in 3b in a non-contact state and pressing ring part 13b as a pressing part formed on the radially inner part of cover part 13a and capable of pressing protective layer part 3d on cut surface 3b And an outer peripheral surface contact portion 14 formed from the end surface anticorrosive portion 13 to the outer peripheral surface 3e at the end of the remaining tube 3a and in contact with the outer peripheral surface 3e.

  The covering portion 13a in the end surface anticorrosion portion 13 is formed so that its bulge height is A in the tube axis direction from the cut surface 3b. Further, the pressing ring portion 13b is formed in a round shape so that the radially inner portion of the covering portion 13a swells. As shown in FIG. 2A, the outer peripheral surface contact portion 14 of the anticorrosion member 11 is based on the connection portion with the covering portion 13a when the anticorrosion member 11 is not attached to the cut surface 3b of the remaining pipe 3a. Further, it is inclined inward in the radial direction so as to form an inclination angle θ with respect to the tube axis direction of the remaining tube 3a. Further, the thickness a of the covering portion 13a in the end face anticorrosion portion 13 is formed to be thicker than the thickness b of the outer peripheral surface contact portion 14, and the maximum thickness c of the pressing ring portion 13b is the thickness of the covering portion 13a. It is formed thicker than the thickness a. For example, the inclination angle θ of the outer peripheral surface contact portion 14 is about 5 to 30 [°], the thickness b of the outer peripheral surface contact portion 14 is about 0.15 to 1.0 [mm], and the thickness a of the covering portion 13a is The swelling height A of the covering portion 13a in the non-pressed state is about 1.0 to 6.0 [mm], and the maximum thickness c of the pressing ring portion 13b is about 0.3 to 2.0 [mm]. It is set to about 5 to 3.0 [mm]. The elastic member forming the anticorrosion member 11 is made of rubber such as SBR, NBR, CR, and EPDM, and has a hardness of about 50 to 95 degrees, for example.

  As shown in FIGS. 1 and 2 (b), the insertion ring 12 is fitted around the outer periphery of the end portion of the remaining tube 3a, so that the insertion protrusion 4 as an outer peripheral protrusion is formed on the outer periphery. In addition, it is provided from the outer peripheral surface 3e at the end of the remaining tube 3a to a position facing the cut surface 3b of the remaining tube 3a. .

  When the insertion ring 12 is fitted to the outer periphery of the end portion of the remaining tube 3a, the outer peripheral surface contact portion 14 of the anticorrosion member 11 is connected to the outer peripheral surface 3e of the end portion of the remaining tube 3a by the inner surface 15a. A pressing portion 15 that presses inward in the radial direction of the tube, a covering portion pressing portion 16 that presses the covering portion 13a in the end surface anticorrosive portion 13 in the tube axis direction and the cutting surface 3b side while elastically deforming the covering portion 13a, An inner circumferential protrusion 17 is formed inwardly in the radial direction from the inside of the contact portion pressing portion 15 and along the circumferential direction, and is fitted into an annular groove 18 formed on the outer periphery of the remaining tube 3a.

  A rubber ring 19 is attached to the inner surface of the inner peripheral projection 17 to prevent corrosion of the annular groove 18 from which the coating has been peeled off by the groove processing, and the inner peripheral projection 17 fits into the annular groove 18. Thus, the anticorrosion treatment of the annular groove 18 is attempted. Further, a tapered surface 4 a that is tapered along the tube axis direction of the remaining tube 3 a is formed on the outer surface of the insertion projection 4 in the insertion ring 12. Since the tapered surface 4a is formed in this way, for example, when the remaining pipe 3a is inserted into a receiving port of another pipe and joined, the remaining pipe 3a can be guided, and the other pipe It is possible to easily expand the diameter of a member such as a lock ring disposed in the receiving port.

  In such a configuration, in order to perform the anticorrosion treatment on the cut surface 3b of the remaining pipe 3a while forming the insertion protrusion 4 on the outer periphery of the end of the remaining pipe 3a at the piping construction site, FIG. As shown in FIG. 2, an annular groove 18 is formed on the outer periphery of a predetermined position at the end of the remaining tube 3a. And the outer peripheral surface contact part 14 in the anticorrosion member 11 is turned back to the opposite side to the cut surface 3b, and the covering part 13a in the end surface anticorrosion part 13 corresponds to the metal part 3c of the cut surface 3b as shown in FIG. After that, the outer peripheral surface contact portion 14 is folded back to the cut surface 3b side, the outer peripheral surface contact portion 14 is brought into contact with the outer peripheral surface 3e of the remaining tube 3a, and the metal portion 3c on the cut surface 3b is formed by the covering portion 13a. The pressure ring portion 13b is brought into contact with the protective layer portion 3d while being covered in a non-contact state, and the anticorrosion member 11 is attached to the cut surface 3b of the remaining tube 3a.

  Next, the divided part of the insertion ring 12 is widened with a diameter expansion jig (not shown), the diameter of the insertion ring 12 is expanded and arranged at the end of the remaining tube 3a, as shown in FIG. 3 (c). The inner ring protrusion 17 of the insertion ring 12 is fitted into the annular groove 18 in the remaining tube 3a, and the corrosion prevention member 11 is covered so that the insertion ring 12 is removed from the outer periphery of the end of the remaining tube 3a. To do.

  When fitting the insertion ring 12, the outer surface 15a of the anticorrosion member 11 is pressed against the outer surface 3e of the remaining tube 3a by the inner surface 15a of the contact portion pressing portion 15 of the insertion ring 12, and The covering portion pressing portion 16 presses the covering portion 13a toward the cut surface 3b while elastically deforming the covering portion 13a so that the bulging height of the covering portion 13a is lower than the bulging height A in the non-pressed state. At this time, the outer peripheral surface contact portion 14 is pressed against the outer peripheral surface 3e of the remaining tube 3a by the inner surface 15a of the contact portion pressing portion 15, and the coating portion 13a thicker than the outer peripheral surface contact portion 14 Since it does not enter between the inner surface 15a of the pressing portion 15 and the outer peripheral surface 3e of the remaining tube 3a, the pressing ring portion 13b can strongly press the protective layer portion 3d on the cut surface 3b. Further, at this time, the covering portion 13a is formed to be curved to cover the metal portion 3c in a non-contact state, and the pressing ring portion 13b is in contact with the protective layer portion 3d. Compared with the case where the covering portion 13a is not in direct contact with the metal portion 3c, it is possible to prevent the force from being dispersed, so that the pressing ring portion 13b presses the protective layer portion 3d with a stronger force. it can. As described above, the covering portion 13a covers the metal portion 3c in a non-contact state. However, since the pressing ring portion 13b is in contact with the protective layer portion 3d, the fluid flowing in the pipe is transferred to the metal portion 3c. And the covering portion 13a can be prevented from entering, so that the corrosion of the metal portion 3c can be prevented.

  When the insertion ring 12 is fitted to the outer periphery of the end portion of the remaining tube 3a, although not shown, the insertion ring 12 and the remaining tube 3a are screwed together using a tapping screw or the like, and the insertion ring 12 is removed. It fixes to the outer periphery of the remaining pipe 3a. In addition, corrosion prevention of the location corresponding to the division part of the insertion ring 12 in the annular groove 18 is performed by an appropriate method such as painting. In this way, the anticorrosion structure of the pipe end surface is configured.

  According to the above configuration, the covering portion 13a in the end surface anticorrosion portion 13 of the anticorrosion member 11 covers the metal portion 3c in the cut surface 3b of the remaining tube 3a, and the pressing ring portion 13b in the end surface anticorrosion portion 13 is in the cut surface 3b. By pressing the protective layer portion 3d, the protective layer portion 3d can be sealed by the pressing ring portion 13b, and the outer peripheral surface contact portion 14 can be sealed by the inner surface 15a of the contact portion pressing portion 15 in the insertion ring 12. The outer peripheral surface 3e can be sealed by the outer peripheral surface contact portion 14 by being pressed inwardly in the pipe radial direction against the outer peripheral surface 3e of the remaining tube 3a. Thereby, the state which the coating | coated part 13a has covered the metal part 3c in the cut surface 3b, ie, the state which the coating | coated part 13a has protected the metal part 3c, can be hold | maintained. Therefore, a reliable anticorrosion treatment can be applied to the metal portion 3c in the cut surface 3b of the remaining tube 3a. Further, the outer peripheral surface contact portion 14 is pressed against the outer peripheral surface 3e by the contact portion pressing portion 15 inward in the radial direction of the tube, thereby stabilizing the anticorrosion member 11 attached to the end of the remaining tube 3a. be able to. Thereby, it can prevent that this anti-corrosion member 11 falls off from the edge part of the remaining pipe 3a. Further, the insertion ring 12 forms the insertion protrusion 4 on the outer periphery of the end portion of the remaining tube 3a, so that the insertion protrusion 4 is easily and quickly formed on the outer periphery of the end portion of the remaining tube 3a. Can do.

  In the above description, the case where the rubber ring 19 for preventing the annular groove 18 is attached to the inner surface of the inner peripheral protrusion 17 of the insertion ring 12 has been described. However, as shown in FIG. Instead of the rubber ring 19, a rubber paint 20 may be applied to the inner surface of the portion 17.

It is a figure which shows the anti-corrosion structure of the pipe end surface of embodiment of this invention. (A) is sectional drawing of the end surface anticorrosion member in FIG. 1, (b) is sectional drawing of an insertion ring. It is a figure which shows the method of attaching an end surface anticorrosion member and an insertion ring to a remaining pipe. It is sectional drawing which shows the state which apply | coated the rubber-type coating material to the inner surface of the internal peripheral protrusion part in an insertion ring. It is a figure which shows the pipe joint which has an earthquake resistance function. It is a figure which shows the state by which the pipe | tube is cut | disconnected.

Explanation of symbols

3a Remaining pipe 3b Cut surface 3c Metal part 3d Protective layer part 3e Outer peripheral surface 4 Insertion protrusion 6 Mortar lining 11 Anticorrosion member 12 Endpiece ring 13 End surface anticorrosion part 13a Covering part 13b Press ring part 14 Outer surface contact part 15 Contacting part pressing part 16 Covering part pressing part

Claims (2)

A metal tube having a protective layer for anticorrosion on the inner surface is cut and formed at the end of the tube where the ground of the metal portion and the protective layer portion on the cut surface are exposed. An end surface anticorrosion part having a covering part for covering and preventing corrosion by covering a metal part, and a pressing part formed on the inner side in the pipe radial direction of the pipe in the covering part, and capable of pressing the protective layer part, and the pipe from the end surface anticorrosion part A first member that is formed on the outer peripheral surface of the end of the tube and has an outer peripheral surface contact portion that contacts the outer peripheral surface of the end of the tube and is formed in an annular shape by an elastic member, An outer peripheral protrusion is formed on the outer periphery of the end, and is provided from the outer peripheral surface of the end of the tube to a position facing the cut surface of the tube, and the outer peripheral surface contact portion is provided on the outer peripheral surface of the end of the tube. Pressing the contact part to press radially inward And a second member formed in a ring shape by a metal member and having a covering portion pressing portion that presses against the cut surface side of the tube while elastically deforming the covering portion. A tube end face, wherein the covering portion is pressed by the covering portion pressing portion and elastically deformed, and the pressing portion presses the protective layer portion by the elastic deformation. Anti-corrosion structure. A pipe which is attached to the end of the pipe where the metal part ground and the protective layer part are exposed in the cut surface of the metal pipe having an anticorrosive protective layer on the inner surface, and is formed in an annular shape by an elastic member An anti-corrosion member on an end surface, which is formed in a curved shape so as to cover the metal portion in the cut surface and prevent corrosion, and is formed on the radially inner portion of the covering portion so as to press the protective layer portion A pipe comprising: an end surface anticorrosion portion having a portion; and an outer peripheral surface contact portion formed from the end surface anticorrosion portion to the outer peripheral surface of the end portion of the tube and contacting the outer peripheral surface of the end portion of the tube. Anti-corrosion member on the end face.

Images