JP2011140971A - Pipe end corrosion preventive structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pipe end corrosion preventive structure easily attachable to an end part of a metallic pipe, and capable of maintaining the corrosion preventive function over a long period. <P>SOLUTION: This pipe end corrosion preventive structure is composed of corrosion preventive rubber (an annular rubber seal member) 2 having an annular recessed part 2a fitted to the end part of the metallic pipe 1 and an annular stainless steel cover 3 having an annular recessed part 3a for pressing in this corrosion preventive rubber 2, and is constituted so as to release air in the annular recessed part 3a of the cover 3 from an air bleeding hole 4 of a bottom surface of the annular recessed part 3a when fitting the cover 3 in the corrosion preventive rubber 2 fitted in the end part of the metallic pipe 1, and the cover 3 is smoothly fitted in the corrosion preventive rubber 2, and the corrosion preventive rubber 2 can be easily and firmly fixed to a pipe 1 end part. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to anticorrosion of the end of a metal pipe, particularly pipe end anticorrosion attached to the end of the pipe for anticorrosion of the pipe end cut surface when a metal pipe used for construction of waterworks is cut at a construction site. Concerning structure.

  When replacing existing metal pipes (mainly ductile cast iron pipes) in installation works such as waterworks, it may be necessary to cut the existing pipes to the specified length at the construction site and connect them to the new pipes. is there. When the existing pipe is cut in this way, the pipe end is usually subjected to anticorrosion coating to prevent rusting of the pipe end cut surface. However, if the valve on the upstream side of the existing pipe cutting part has deteriorated over time and water cannot be stopped sufficiently, or construction work is being carried out during drainage of pipe water between the existing pipe cutting part and the upstream valve due to construction time restrictions. When it is unavoidable, a part of the pipe end cut surface of the existing pipe gets wet with the pipe water, and the coating becomes difficult.

  Therefore, as a pipe end anti-corrosion measure other than the anti-corrosion coating, as shown in FIG. 5, after the anti-corrosion rubber (annular rubber seal member) 52 having the annular recess 52a is fitted into the end of the metal pipe 51, the anti-corrosion A method of inserting a metal fixing ring 53 into the inner periphery of the rubber 52 and expanding the diameter of the fixing ring 53 to fix the anticorrosion rubber 52 to the end of the pipe 51 is performed.

  Moreover, when taking said anti-corrosion method, in order to maintain the anti-corrosion function long, using the fixing ring 53 as shown in FIG. 6 is proposed (refer patent document 1). In the anticorrosion rubber fixing method using the fixing ring 53, first, the belt-like fixing ring 53 shown in FIG. 7 is bent so that both ends thereof overlap, and the engaging portion 54 at one end is inserted into the opening 55 on the other end side. At the same time, a stopper 56 formed on the other end side is inserted into one of the openings 57 on the one end side to form an annular shape (the state shown in FIG. 6). Then, after inserting the annular fixing ring 53 into the inner periphery of the anticorrosion rubber 52 as shown in FIG. 5, the diameter of the fixing ring 53 is increased by a jig, and the inner wall on the inner peripheral side of the annular recess 52 a of the anticorrosion rubber 52. Is pressed against the inner peripheral surface of the end portion of the tube 51, and the tip end portion of the stopper 56 is folded back so that the diameter of the fixing ring 53 is not reduced. As a result, the anticorrosion rubber 52 can be brought into close contact with the inner peripheral surface of the end portion of the pipe 51 over a long period of time, thereby preventing the anticorrosion function from being lowered.

JP 2001-141175 A

  However, in the pipe end anticorrosion structure using the fixing ring described in Patent Document 1, it is necessary to fold back the stopper in a state where the diameter of the fixing ring inserted into the inner periphery of the anticorrosion rubber is sufficiently expanded with a jig, This anticorrosive rubber fixing work has a drawback that it is complicated.

  Then, the subject of this invention is providing the pipe end anti-corrosion structure which can be easily attached to the edge part of a metal pipe, and can maintain an anti-corrosion function over a long period of time.

  In order to solve the above-described problems, the pipe end anticorrosion structure of the present invention is formed of an elastic body, and has an annular seal member having an annular recess that fits with an end of a metal pipe, and higher rigidity than the seal member. The seal member is formed of an annular cover having an annular recess into which the seal member is press-fitted, and the cover has an air vent hole on the bottom surface of the annular recess and is fitted into the end of the metal tube When the cover is fitted into the air, the air in the annular recess of the cover escapes from the air vent hole.

  That is, when the cover for fixing the seal member is fitted to the seal member fitted to the end of the metal tube, the air in the annular recess of the cover is released from the air vent hole on the bottom surface of the annular recess. The cover can be smoothly fitted into the seal member, and the seal member can be easily and firmly fixed to the pipe end.

  In the above configuration, it is desirable to provide a protrusion on at least one of the outer peripheral side inner wall surface and the inner peripheral side inner wall surface of the annular recess of the cover. In this way, the anticorrosion function can be maintained for a long time even if the dimensional accuracy of the inner diameter and outer diameter of the metal pipe to be protected against corrosion is somewhat low. That is, even when the tube thickness is thinner than the designed value, the seal member can be firmly fixed to the tube end portion by the protrusion in the annular recess of the cover biting into the seal member. In addition, when the tube thickness is thicker than the design value, the seal member is firmly fixed to the end of the tube. Of course, when the cover is fitted, a part of the seal member that is pressed by the projection is between the projections. Since it is deformed so as to escape into the gap, the labor for fixing the seal member is almost the same as when no projection is provided.

  As described above, in the pipe end anticorrosion structure of the present invention, when the cover for fixing the seal member is fitted to the seal member fitted to the end of the metal pipe, the air in the annular recess of the cover is annular. Since the air is removed from the air vent hole on the bottom surface of the recess, the cover can be smoothly fitted into the seal member, and the seal member can be easily and firmly fixed to the end portion of the pipe. Therefore, it can be easily attached to the end of the metal tube, and the anticorrosion function can be maintained for a long time.

Exploded perspective view of tube end anticorrosion structure of embodiment a is a front view of the anticorrosion rubber of FIG. 1, and b is an enlarged sectional view taken along line II-II of a. a is a front view of the cover of FIG. 1, and b is an enlarged sectional view taken along line III-III of a. Sectional drawing which shows an example of the connection of the metal pipe and pipe joint which attached the pipe end anti-corrosion structure of FIG. Cross-sectional view of conventional pipe end anticorrosion structure The perspective view which shows an example of the fixing ring used for the pipe end anti-corrosion structure of FIG. FIG. 6 is a developed plan view of the fixing ring of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 4. As shown in FIG. 1, the pipe end anticorrosion structure includes an anticorrosion rubber (annular rubber seal member) 2 fitted into the end of the metal pipe 1 and an annular cover 3 fitted with the anticorrosion rubber 2. Therefore, the cut end surface (cut surface) 1a of the existing metal tube 1 is attached to the end portion of the tube 1 to prevent rusting.

  As shown in FIGS. 1 and 2, the anticorrosion rubber 2 has an annular recess 2 a that opens to one side in the axial direction and into which the end of the metal tube 1 is fitted from the axial direction. Moreover, the taper surface 2b is formed in the outer peripheral side of an axial direction other end part.

  As shown in FIGS. 1 and 3, the cover 3 is made of stainless steel and has an annular recess 3a that opens to one side in the axial direction and into which the anticorrosion rubber 2 is press-fit from the axial direction. A tapered surface 3b that matches the shape of the tapered surface 2b of the anticorrosion rubber 2 is formed on the inner surface on the bottom side of the annular recess 3a, and the same inclination is formed on the outer side (the outer peripheral side of the other end in the axial direction) of the tapered surface 3b. The taper surface 3c is formed. Also, four air vent holes 4 are formed at equal intervals in the circumferential direction on the bottom surface of the annular recess 3a, and the ridges 5 extending in the axial direction are respectively formed on the outer peripheral side inner wall surface and the inner peripheral side inner wall surface of the annular recess 3a. 6 are provided at intervals of 30 ° in the circumferential direction. And the taper surfaces 5a and 6a of 15-30 degrees are formed in the one end part of each protrusion 5, 6 so that the fitting to the anticorrosion rubber 2 can be performed smoothly.

  The procedure for attaching the pipe end anticorrosion structure to the end of the metal pipe 1 is as follows. First, only the anticorrosion rubber 2 is fitted into the end of the pipe 1 and then the cover 3 is fitted with the anticorrosion rubber 2 with a plastic hammer or the like. It is only necessary to fix the anticorrosion rubber 2 by driving in. When the anticorrosion rubber 2 is fixed, the air in the annular recess 3a of the cover 3 escapes from the air vent hole 4 of the cover 3, so that the cover 3 can be smoothly fitted into the anticorrosion rubber 2, and the anticorrosion rubber 2 is attached. It can be easily and firmly fixed to the end of the tube 1.

  Here, since the protrusions 5 and 6 are provided on the outer peripheral side inner wall surface and the inner peripheral side inner wall surface of the annular recess 3a of the cover 3, even when the thickness of the metal tube 1 is thinner than the design value, The protrusions 5 and 6 can bite into the anticorrosion rubber 2 so that the anticorrosion rubber 2 can be firmly fixed to the end of the tube 1.

  Therefore, this pipe end anticorrosion structure can be easily attached to the end of the metal pipe 1, and the anticorrosion function for the pipe end face 1a can be maintained for a long period of time.

  Further, since the taper surface 3c is formed on the outer peripheral side of the other axial end portion of the cover 3, as shown in FIG. 4, the push-on in which the rubber ring 7 for sealing is mounted on the inner peripheral surface of the tip portion. Connection with the type of pipe joint 8 can also be performed easily.

  In the above-described embodiment, the anticorrosion rubber is used as the seal member fitted into the end portion of the metal tube. However, the material of the seal member is not limited to rubber and may be an elastic body having a sealing property. The material of the cover is not limited to stainless steel as in the embodiment, but may be any material as long as it has higher rigidity than the seal member. For example, a synthetic resin such as nylon 6 can be used.

  Furthermore, the number of protrusions of the cover and the number of air vent holes are not limited to those in the embodiment, and can be arbitrarily set. Moreover, the protrusion provided in the cover of the embodiment can be changed to a protrusion having an arbitrary shape.

1 Metal tube 1a End face (cut surface)
2 Anticorrosion rubber 2a Annular recess 2b Tapered surface 3 Cover 3a Annular recess 3b, 3c Tapered surface 4 Air venting holes 5, 6 Projection 5a, 6a Tapered surface 7 Rubber ring 8 Pipe joint

Claims (2)

  An annular seal member that is formed of an elastic body and has an annular recess that fits into the end of the metal tube, and an annular seal member that is formed of a material having higher rigidity than the seal member and into which the seal member is press-fitted. The cover has an air vent hole in a bottom surface of the annular recess, and when the cover is fitted into a seal member fitted into an end of the metal tube, A pipe end anticorrosion structure that allows air to escape from the air vent hole.   The pipe end anticorrosion structure according to claim 1, wherein a protrusion is provided on at least one of an outer peripheral side inner wall surface and an inner peripheral side inner wall surface of the annular recess of the cover.

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