JP2011120469A - Pipe joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pipe joint for connecting cable protective sheath pipes used for protective pipes such as optical cables embedded into the ground and bridges, wherein the pipe joint has high cutoff performance, restrains an absorption expandable material from protruding into a pipe inside and from crushing the pipe end during long-term use, and is easily manufactured. <P>SOLUTION: The pipe joint 1 has a seal member integrated so as to face an outer peripheral surface of the pipe to be connected on an inner peripheral surface of a substantially cylindrical pipe joint body member 11, wherein the seal member is composed of first seal members 12 spirally disposed so as to have a predetermined interval and a second seal member 13 disposed so as to be astride the adjacent portion of each first seal member. At least one of the first seal member 12 and the second seal member 13 is taken as a seal material formed from the absorption expandable material. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a pipe joint used for connecting, for example, a protective pipe such as an optical cable buried in the ground or a cable protective sheath pipe used for a bridge or the like, in particular, a pipe using a material having a water-absorbing expansibility. Regarding fittings.

  About such a pipe joint and its manufacturing method, what was disclosed by patent document 1 is known (refer FIG. 9). Patent Document 1 discloses a laminated structure in which the outer peripheral surface of a spiral tube to be connected is screwed into a spiral irregularity, and the joint inner peripheral surface is a water-absorbent expandable nonwoven fabric 92 and the outer peripheral surface side is a synthetic resin (91). A molded integrated pipe joint is disclosed. In such a pipe joint, the connection between the pipes is completed only by screwing the pipe joint into the end part of the pipe to be connected, and water has come to the connection part by the action of the water-absorbing expandable nonwoven fabric provided on the inner surface. In this case, the water-absorbing expandable nonwoven fabric expands and seals the gaps between the connection portions to exhibit the water stoppage of the connection portions.

  In addition, Patent Document 1 relates to the above-described method for manufacturing a pipe joint. After the water-swellable non-woven fabric is wound around a core-shaped fixed mold, the non-woven fabric is preformed, and then the fixed mold is installed in the injection mold. A method of manufacturing a pipe joint by performing insert molding for injecting resin is disclosed.

  Furthermore, in Patent Document 2, regarding a similar pipe joint manufacturing method, after introducing a pre-formed water-absorbing non-woven fabric into a pipe joint body member that has been preformed, spiral irregularities are introduced. A method is disclosed in which a jig having an outer peripheral surface is screwed inside a water-swellable non-woven fabric and the water-swellable non-woven fabric is integrated with the inner peripheral surface of the pipe joint body member.

JP 2006-26899 A Patent Registration No. 3678742

  However, these conventional pipe joints and their manufacturing methods have been required to be further improved as shown below. That is, in the pipe joints disclosed in Patent Document 1 and Patent Document 2, in order to improve the water-stopping performance, the water-stopping portion is formed in a cylindrical shape over the entire inner peripheral surface of the pipe joint, so to speak, an excessive water-absorbing expandable material is integrated. However, if moisture is absorbed over a long period of time with such a pipe joint connected to the pipe, there will be no escape space for the water-swellable material that has expanded due to excessive water absorption, and the water-swelling expansibility from the connection end of the pipe will disappear. There is a risk that the material may enter the pipe, or the pipe end may be crushed so as to be bent toward the inside of the pipe, resulting in a problem that the space inside the pipe becomes narrow.

  Also, in these conventional pipe joints, it was effective to set the clearance between the pipe and the joint to the minimum in order to improve the water stop performance of the joint. With some tubes, there is a possibility that a tube cannot be inserted or a tube that is difficult to insert is generated. Furthermore, if the water-swellable material of the pipe joint absorbs water (absorbs moisture) while the pipe joint is stored after manufacture, the pipe cannot be inserted and the pipe joint may not be used.

  Further, the conventional pipe joint has not been easily manufactured. In the manufacturing method disclosed in Patent Document 1, although the pipe joint body and the water-absorbent expandable nonwoven fabric are firmly integrated by injection molding, there is a drawback that the manufacturing apparatus becomes a considerably large apparatus. If the process of winding the water-swellable non-woven fabric on the core mold of the injection mold is performed manually, the manufacturing equipment can be prevented from becoming large-scale, but the water-swellable material is attached to the core mold. The process is time consuming and expensive to manufacture.

  Moreover, like the manufacturing method disclosed in Patent Document 2, it is difficult to apply the water-swellable nonwoven fabric to the inside of the molded pipe joint body for the following reason. For example, if the adhesive for pasting is too strong, it becomes difficult to introduce the water-absorbing expandable nonwoven fabric into the pipe joint body. On the other hand, if an adhesive with low adhesive strength is used, the affixing operation is simplified, but the water-swellable material may peel off from the main body due to changes over time. In particular, in a corrugated pipe joint having a complicated inner peripheral surface shape, if the circumferential length of a cylindrical water-swellable material to be affixed to the inner surface is long, the water-swellable material will bend and sag when affixed. A sticking failure may occur. On the other hand, if the circumference is short, the water-swellable material is stretched and pasted, so that the water-swellable material is easily peeled off from the main body due to a change with time or is likely to be poorly pasted.

Therefore, the present invention provides a pipe joint that has a sufficient water-stopping property and can prevent the water-swellable material from protruding into the pipe or crushing the end of the pipe even during long-term use, and is easy to manufacture. The purpose is to do.
Another object of the present invention is to provide a production method capable of efficiently producing such a pipe joint.

  As a result of intensive studies, the inventors have arranged the sealing material provided on the inner peripheral surface of the pipe joint so as to straddle the first sealing material and the first sealing material that are spirally arranged at predetermined intervals. The present invention has been completed by discovering that the above-mentioned problems can be solved by forming the second sealing material and forming at least one of the first sealing material and the second sealing material with a water-swellable material.

  The present invention is a pipe joint in which a sealing material is integrated with an inner peripheral surface of a substantially cylindrical pipe joint body member so as to face an outer peripheral surface of a pipe to be connected, and the sealing material has a predetermined interval. The first sealing material and the second sealing material are configured by a first sealing material disposed in a spiral shape and a second sealing material disposed across adjacent portions of the first sealing material. At least one of these is a pipe joint characterized in that it is a sealing material made of a water-swellable material (claim 1).

  In the pipe joint of the present invention, it is preferable to dispose the second seal material in a substantially tube axis direction so as to cross the entire inner peripheral surface of the main body member on which the first seal material is disposed (Claim 2), or The pipe joint is configured so as to have a corrugated portion to which a corrugated pipe having a spiral ridge is connectable, and the first sealing material is disposed along the inner peripheral surface of the large diameter portion of the corrugated part of the pipe joint body member. (Claim 3). Or a pipe joint is comprised so that it may have a corrugated part which can connect a corrugated pipe | tube which has a spiral uneven | corrugated strip, and a 1st sealing material is along the internal peripheral surface of the small diameter part of the corrugated part of a pipe joint main body member. (Claim 4). Alternatively, the first sealing material may be disposed so that the inner circumferential surface of the first sealing material does not form a step with the inner circumferential surface of the portion of the pipe joint body member where the first sealing material is not disposed. Preferred (claim 5).

  Moreover, this invention supplies the tape-shaped raw material which should become a 1st sealing material, and the synthetic resin strip which should become a pipe joint main body member to a pipe forming axis | shaft, and the 1st sealing material is provided to the pipe joint main body inner periphery. A spiral forming step of forming an indefinite length pipe joint member in which the pipe is arranged and integrated, and a cutting step of cutting the pipe joint member obtained in the spiral forming step into a predetermined length to obtain a fixed-length pipe joint, The method of manufacturing a pipe joint according to claim 1 by a second sealing material integration step in which a tape-shaped second sealing material is disposed and integrated on the inner peripheral surface of a fixed-length pipe joint obtained in the cutting step. (Claim 7).

  According to the pipe joint of the present invention (Claim 1), the portion where the pipes are connected has sufficient water-stopping properties, and even when used for a long time, the water-absorbing expandable material protrudes into the pipe or crushes the end of the pipe. It is possible to provide a pipe joint that is easy to manufacture.

  Furthermore, as a more preferable form of the present invention, when the second sealing material is disposed substantially in the tube axis direction so as to cross the entire inner peripheral surface of the main body member on which the first sealing material is disposed (claim) 2) The reliability of waterstop is further improved.

  Moreover, as a more preferable form of the present invention, when the first sealing material is disposed along the inner peripheral surface of the large-diameter portion of the corrugated portion of the pipe joint main body member having the spiral ridges ( According to the third aspect of the present invention, the arrangement of the second sealing material is facilitated, and the pipe joint is easier to manufacture.

  Further, as a more preferable embodiment of the present invention, when the first sealing material is disposed along the inner peripheral surface of the small diameter portion of the corrugated portion of the pipe joint main body member having the spiral ridges (claim) Item 4), the second seal material is easily disposed, and the pipe joint is easier to manufacture.

  Moreover, as a more preferable form of the present invention, if the inner peripheral surface of the first seal material does not cause a step from the inner peripheral surface of the portion of the pipe joint body member where the first seal material is not disposed ( (5) The clearance between the pipe joint and the outer peripheral surface of the pipe can be set small, and the reliability of water-stopping can be further increased.

  Moreover, according to the pipe joint manufacturing method of the present invention (Claim 7), the pipe joint of the present invention can be manufactured efficiently.

It is a fragmentary sectional view which shows the structure of the pipe joint of 1st Example of this invention. It is a schematic diagram which shows the spiral shaping | molding process in the manufacturing method of the pipe joint of 1st Example of this invention. It is a fragmentary sectional view which shows the structure of the pipe joint of 2nd Example of this invention. It is a fragmentary sectional view which shows the structure of the pipe joint of 3rd Example of this invention. It is a fragmentary sectional view which shows the structure of the pipe joint of 4th Example of this invention. It is a fragmentary sectional view which shows the structure of the pipe joint of 5th Example of this invention. It is a fragmentary sectional view which shows the structure of the pipe joint of 6th Example of this invention. It is a fragmentary sectional view which shows the structure of the pipe joint of 7th Example of this invention. It is a fragmentary sectional view which shows the structure of the conventional pipe joint.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a partial sectional view showing a pipe joint 1 according to the present invention, and an upper half is shown as a sectional view. The substantially cylindrical pipe joint 1 is a pipe joint in which a first seal material 12 and a second seal material 13 are integrated with a pipe joint main body member 11 so as to face the outer peripheral surface of a pipe to be connected. . The pipe joint 1 is a pipe joint for connecting a corrugated pipe (not shown) whose outer peripheral surface is formed in a spiral concave-convex strip, and the spiral concave-convex strip on the outer periphery of the corrugated pipe and the pipe joint inner circumference The spiral concavo-convex strips on the surface are matched, and the corrugated pipe is relatively rotated so as to be screwed into the pipe joint 1 and connected. And a pair of corrugated pipe can be connected by screwing in the edge part of a corrugated pipe from the both sides of the pipe joint 1, respectively.

  The pipe joint main body member 11 is a synthetic resin in which an inner peripheral surface having a spiral concave and convex shape is formed so as to substantially match the spiral concave and convex shape of the outer peripheral surface of the corrugated pipe to be connected and to have an appropriate clearance. This is a substantially cylindrical member. In particular, the tube wall of the main body member is provided so that the entire tube wall is alternately formed with a large-diameter portion 111 protruding outward in the radial direction and a small-diameter portion 112 recessed inward in the radial direction. It is a corrugated part, and the tube wall is formed in a substantially uniform thickness.

  Examples of the synthetic resin for forming the main body member 11 include hard synthetic resins such as polyethylene resin, polypropylene resin, and vinyl chloride resin. The synthetic resin material for forming the main body member 11 may be formed of a relatively soft resin such as rubber or thermoplastic elastomer in addition to the illustrated hard synthetic resin, or may be formed by combining a hard synthetic resin and a soft synthetic resin. Also good. The main body member 11 can be manufactured by blow molding, injection molding, a spiral molding method described later, or the like.

  The first sealing material 12 is a sealing material made of a water-swellable non-woven fabric, and the tape-like water-swellable non-woven fabric cut into a predetermined width is spirally formed such that the side edges thereof have a predetermined distance d from each other. The spiral seal material is affixed to the inner peripheral surface of the main body member. In this embodiment, the 1st sealing material 12 is stuck and integrated with the main body member 11 along the internal peripheral surface of the large diameter part 111 of a main body member.

  The second sealing material 13 is also a sealing material made of a water-swellable non-woven fabric, and the tape-like water-swellable non-woven fabric cut to a predetermined width is adjacent to each other in a direction generally along the tube axis direction. It is the sealing material affixed along the internal peripheral surface of the main body member 11 and the 1st sealing material 12 over the full length of a pipe joint so that it may straddle the part 12a, 12b, 12c, 12d, 12e. In the present embodiment, the second sealing material 13 is provided at one place in the circumferential direction of the main body member 11.

The water-swellable non-woven fabric constituting the first seal material and the second seal material is a non-woven fabric in which a water-swellable resin is supported on a non-woven fabric material. The form of supporting the water-swellable resin can be a powder form, a fiber form, an impregnation, a coating form, or the like. The water-absorbing expandable resin is a resin that has the property of absorbing moisture and swells, and exemplifies a resin containing polyacrylic acid sodium salt as a main component or a resin containing an alkene (alkylene) oxide modified compound as a main component. Can do. In particular, the latter exhibits a water-swelling property even with respect to water having a relatively high ion concentration such as seawater. Therefore, it is preferable to use the latter in an environment where salt is high.
Examples of commercially available water-swellable resins include fibrous products such as Lanseal (registered trademark Toyobo Co., Ltd. product). Examples of the alkene (alkylene) oxide-modified water-absorbent expandable resin include Aqua Coke (registered trademark, Sumitomo Seika Co., Ltd. product).

  The base fiber constituting the nonwoven material is not particularly limited, but is preferably a synthetic resin fiber, and synthetic resin fibers such as polyester fiber, nylon fiber, polyethylene terephthalate fiber, acrylic fiber, and polypropylene fiber can be used. . The base fiber may be a poorly hydrophilic fiber such as polypropylene fiber or polyethylene terephthalate (PET) fiber, but is preferably a hydrophilic fiber such as acrylic fiber or nylon fiber. The basis weight of the nonwoven fabric is preferably about 100 to 500 g / square meter, more preferably 200 to 300 g / square meter so that appropriate elasticity can be obtained in the nonwoven fabric layer.

  In addition, the material constituting the first sealing material and the second sealing material is not limited to the water-absorbing and expansive nonwoven fabric, and other water-absorbing materials as long as the material absorbs moisture and expands and has a sealing property. An inflatable material can also be used. Other water-swellable materials include, for example, materials obtained by processing the above-described water-swellable resin into a sheet or string shape, and these materials are laminated on other sheet-like materials made of rubber, resin, water permeable material, etc. A material etc. can be illustrated. In order to increase the ease of connection operation when connecting a pipe joint and a pipe, the water-absorbing and expansive material used in the present invention is preferably provided with elasticity and cushioning, and the pipe joint body member 11 It is preferable that the material has flexibility and stretchability so that it can be easily attached to the inner peripheral surface. Nonwoven fabrics are particularly suitable as those having such properties.

  The usage method and effect of the pipe joint 1 of the present invention will be described. The pipe joint 1 of 1st Embodiment of this invention can connect a corrugated pipe just by screwing the corrugated pipe | tube which has a helical uneven | corrugated strip like the conventional pipe joint. Further, when water comes to the connecting portion, the water-swellable material (water-swellable non-woven fabric in this embodiment) of the first sealing material 12 and the second sealing material 13 expands, and the pipe joint and the corrugated pipe The space between the two is sealed to be watertight. At this time, since the spiral first sealing material 12 and the second sealing material 13 provided across the tube axis direction are provided in combination, the sealing line (annularly closed by both sealing materials ( For example, a dotted line in FIG. 1) is completed, and the connection portion between the pipe and the pipe joint is stopped.

In particular, in the present embodiment, since the second seal material is disposed in a substantially tube axis direction so as to cross the entire inner peripheral surface of the main body member on which the first seal material is disposed, the seal line closed in an annular shape Are formed in a composite manner, and the reliability of water-stopping is further improved.
In the present invention, the first sealing material 12 and the second sealing material are disposed so as to overlap each other, but in the present invention, both the sealing materials are made of a water-swellable material. Therefore, even when there is a step or a gap at the intersection of the first sealing material 12 and the second sealing material 13 when sticking, when water comes in use, these steps or The gap is filled and a good watertight seal is made. As will be shown in another embodiment to be described later, it is obvious that this effect is exhibited if either one of the first sealing material 12 and the second sealing material 13 is made of a water-expandable material. is there.

  Furthermore, in the pipe joint 1 of the present invention, since the adjacent side edges of the first seal material are arranged in a spiral shape having a predetermined interval, the seal material is pasted on the inner surface of the pipe joint. The part which is not worn is left. As a result, even if the first sealing material 12 or the second sealing material 13 absorbs water and expands excessively, the excessively expanded water-swellable material can wrap around the portions where these sealing materials do not exist. . As a result, even when placed in an environment where water is present for a long period of time, the expanded water-absorbing expansible material enters the inside of the tube from the end of the tube, or due to the pressure of the expanded water-absorbing expansible material. It is possible to suppress or prevent the end of the tube from collapsing inward. In addition, the amount of water-swellable material used can be saved, resulting in cost advantages.

  Moreover, in the pipe joint of the present invention, the space between the adjacent side edges of the first seal material is a space from which the expanded water-absorbing and expansible material can escape, so compared with the conventional pipe joint, A water-swellable material having a higher expansion ratio can be used. That is, in the conventional pipe joint, if the expansion ratio of the water-swellable material is too large, a problem such as the water-swelling material sticking out into the pipe is likely to occur, so it is difficult to use a water-swellable material having a large expansion ratio. However, according to the present invention, since occurrence of such a problem is suppressed, a water-swellable material having a higher expansion ratio can be used, and the range of selection of the water-swellable material is widened.

  Moreover, since the seal material is provided only partially on the inner peripheral surface of the pipe joint, even when it is necessary to insert the pipe while compressing the seal material, when inserting (screwing) the pipe to be connected The operation force is relatively small. As a result, even if the clearance between the pipe joint body or the seal material and the corrugated pipe is set to be smaller than that of the conventional pipe joint, the operating force may become excessive and the joint may not be connectable. It is suppressed and the clearance can be set small. If the clearance is small, the water-stop reliability of the pipe joint can be further increased.

  Moreover, in this embodiment, the sealing material affixed on the inner peripheral surface of a pipe joint is typically about 1/4 to 1/2 pitch wide of a spiral rugged strip, and is used for a conventional pipe joint. Compared with the cylindrical water-absorbing expandable nonwoven fabric, it has a narrow width. In conventional pipe joints, the degree of stretchability of the water-swellable material had to be increased in order to bond the cylindrical water-swellable material along the complicated inner peripheral surface shape of the pipe joint body member. In this invention, the complexity of the unevenness | corrugation of the surface which should stick a sealing material is reduced, and the degree of the expansion / contraction degree of a sealing material may be comparatively low. Therefore, according to the present invention, even if a water-swellable material inferior in stretchability is used, it can be bonded and integrated along the inner peripheral surface of the pipe joint main body 11, and the range of selection of the water-swellable material is expanded.

  Hereinafter, the manufacturing method of the pipe joint 1 of this invention is demonstrated. FIG. 2 is a schematic view showing a spiral molding process for forming an indefinite length pipe joint member P in which the first sealing material 12 is spirally arranged and integrated on the inner peripheral surface of the main body member 11. In this process, a pipe forming shaft 21 that is rotationally driven by a known pipe forming apparatus has a predetermined cross section (in the present embodiment, the reverse) from a water-swellable material tape T1 cut to a predetermined width and a resin extrusion apparatus. The synthetic resin strip T2 in a semi-molten state extruded in a hat shape) is continuously wound and spirally wound, and both end portions of adjacent synthetic resin strips are overlapped with each other and integrated with each other. A corrugated cylindrical tube wall having a spiral ridge is formed, and the water-swellable material 12 is bonded and integrated along the inner peripheral surface of the large-diameter portion 111 of the corrugated cylindrical portion. An indefinite length pipe joint member P integrated in a spiral shape is obtained. The water-swellable material may be bonded using an adhesive or a pressure-sensitive adhesive, or may be welded using the amount of heat of the semi-molten synthetic resin strip T2.

  Following the spiral molding process, a cutting process is performed. In the cutting step, the pipe joint member P having an indefinite length obtained in the spiral molding process is cut into a predetermined length by a cutter or the like, and the pipe joint member Q is obtained.

  Subsequent to the cutting step, a second sealing material integration step is performed. In the second sealing material integration step, a water-swellable material that has been cut into a tape shape with a predetermined width is applied to the inner peripheral surface of the pipe joint member Q that has been cut to a predetermined length over the entire length of the pipe joint member Q. The first seal member is bonded and integrated along the inner peripheral surface of the pipe joint member Q so as to straddle the adjacent portions of the first seal material in a direction substantially along the pipe axis direction. The water-swellable material of the second sealing material may be bonded using an adhesive or an adhesive material. The second sealing material integration step can be performed manually, but can also be mechanized. By sequentially performing the above steps, the pipe joint 1 according to the first embodiment of the present invention can be manufactured.

  According to the manufacturing method, the following effects can be obtained. That is, according to this manufacturing method, at the same time that the pipe joint main body 11 is formed, the first seal material can be spirally bonded and integrated with the inner peripheral surface thereof, and such a pipe joint member P is used. Can be manufactured continuously with indefinite length, and the production efficiency is very high. Therefore, according to this manufacturing method, the pipe joint of this invention can be manufactured efficiently.

  Moreover, when the 1st sealing material 12 is adhere | attached along the internal peripheral surface of the large diameter part 111 of the pipe joint main body member 11 like this embodiment, the 2nd sealing material 13 is followed along a pipe-axis direction. When sticking, the unevenness | corrugation of the internal peripheral surface of the main body member 11 is reduced by the 1st sealing material 12, and the adhesion | attachment operation | work of a 2nd sealing material becomes easier.

  In the pipe joint 1 of the present invention, the first sealing material 12 is later spirally bonded and integrated to the inner peripheral surface of a preformed pipe joint main body member 11, and the second sealing material 13 is further connected to the pipe. It can also be manufactured by bonding and integrating along the axial direction. In that case, the first sealing material and the second sealing material can be bonded manually. In addition, the surface shape of the region to which the sealing material is bonded in the pipe joint of the present invention is relatively simple compared to that in the conventional pipe joint, so the bonding process that is performed manually is mechanized. It is relatively easy.

  The present invention is not limited to the above embodiment, and can be implemented with various modifications. Other embodiments of the present invention will be described below. However, in the following description, portions different from the above-described embodiment will be mainly described, and descriptions of the same portions will be omitted.

  In FIG. 3, the pipe joint 2 of the 2nd Embodiment of this invention is shown. In the present embodiment, the pipe joint body member 21 and the first sealing material 22 are configured in the same manner as in the first embodiment described above. However, in the present embodiment, the second sealing material 23 is made of soft rubber or In addition to being formed of a soft resin elastomer, the second sealing materials 23 and 23 are partially provided. In other words, in the present embodiment, the second sealing material 23 extends across adjacent portions (between 22a and 22b and between 22d and 22e in the figure) of the first sealing material arranged in a spiral shape. It is disposed and integrated with the main body member 21. The end portions of the second sealing materials 23, 23 may abut against the side edge portions of the first sealing material 22, or may ride on the side edge portions of the first sealing material 22.

  Even in the present embodiment, at least one second sealing material 23 is disposed at a portion facing the outer peripheral surface of the pipe to be connected so as to span between adjacent first sealing materials. Thus, a closed seal line can be completed to obtain a predetermined water stoppage.

  The second sealing material is a member having an appropriate thickness and elasticity so as to be sandwiched between the inner peripheral surface of the pipe joint main body member 21 and the outer peripheral surface of the pipe to be connected in a close contact state and perform a water stop function. Yes, those made of a thermoplastic elastomer or rubber can be preferably used, and those made of a thermoplastic elastomer particularly rich in flexibility can be preferably used. Further, in order to reduce the insertion resistance of the pipe and increase the water stop, it is preferable to integrally provide a narrow protrusion on the inner peripheral surface side of the second seal material. The second sealing material may be attached in such a direction as to connect the matching first sealing materials 22 (for example, between 22a and 22b).

  In FIG. 4, the pipe joint 3 of the 3rd Embodiment of this invention is shown. In the present embodiment, the configuration and attachment method of the pipe joint main body member 31 and the second seal material 33 are the same as those in the first embodiment, but the first seal material 32 is configured by a seal material that is not a water-expandable material. Has been. That is, the first sealing material 32 is a sealing material formed of a soft thermoplastic elastomer, particularly a flexible thermoplastic elastomer such as an olefin-based thermoplastic elastomer, and is spirally formed on the inner peripheral surface of the large-diameter portion 311 of the main body member 31. Is integrated with the adhesive. As shown in FIG. 4, the first seal member is a seal material in which a protrusion 322 is integrally formed at a substantially central portion of a substantially flat tape-like base 321, and the protrusion 322 is a spiral of the pipe joint body 31. Are bonded and integrated so as to be along the direction. When a corrugated pipe (not shown) is screwed into the pipe joint 3 of the present embodiment, the first seal is provided between the inner peripheral surface of the pipe joint main body member 31 and the outer peripheral surface of the large-diameter portion of the corrugated pipe. The material 32 is sandwiched and closely adhered to exhibit water-stopping properties.

  Even in the present embodiment, the closed seal line is completed by the spiral first seal member 32 and the second seal member 33 disposed in the portion facing the outer peripheral surface of the pipe to be connected. The desired water stoppage can be obtained.

  When the first sealing material 32 is made of rubber or thermoplastic elastomer as in the present embodiment, it is preferable to provide the protrusion 322 on the first sealing material 32 as described above, and to provide the protrusion 322. As a result, it becomes easy to ensure an appropriate sealing property, and it is possible to reduce the operating force when screwing the corrugated tube.

  In the case where the first sealing material 32 is made of rubber or thermoplastic elastomer as in this embodiment, it is preferable to manufacture the pipe joint by a method similar to the manufacturing method of the first embodiment. In this case, in the spiral molding process shown in FIG. 2, instead of the water-expandable material tape T1, a thermoplastic elastomer is extruded into a tape shape in a semi-molten state so as to be a cross section of the first seal material 32, What is necessary is just to supply to a shaping | molding axis | shaft.

  In FIG. 5, the pipe joint 4 of the 4th Embodiment of this invention is shown. In the present embodiment, both the first sealing material 42 and the second sealing material 43 are formed of a water-swellable non-woven fabric, the first sealing material 42 is spiral, and the second sealing material is between adjacent first sealing materials. However, in this embodiment, the pipe joint body member 41 has a smooth cylindrical inner peripheral surface. The point is different. That is, the pipe joint 4 of this embodiment is for connecting a pipe (not shown) formed in a cylindrical shape with a smooth outer peripheral surface.

  Moreover, in this embodiment, after the 2nd sealing material 43 is first adhere | attached linearly along the pipe-axis direction on the internal peripheral surface of the pipe joint main body member 42, the 1st sealing material 42 is helically formed. It is stuck.

  Even in the present embodiment, a closed seal line is completed by the spiral first seal member 42 and the second seal material 43 disposed in the portion facing the outer peripheral surface of the pipe to be connected. The desired water stoppage can be obtained. Thus, in this invention, the same effect can be exhibited regardless of which of the first sealing material 42 and the second sealing material 43 is inside.

  Further, as is clear from the embodiment shown above, the present invention is not limited to a pipe joint for screwing and connecting corrugated pipes having spiral ridges, but a substantially cylindrical pipe. A pipe joint for inserting and connecting an end portion of a pipe inside the joint, and the above-described first seal member and second seal member are provided on the pipe joint inner peripheral surface facing the outer peripheral surface of the pipe to be connected. Are widely included.

  In FIG. 6, the pipe joint 5 of the 5th Embodiment of this invention is shown. In the present embodiment, the configuration of the pipe joint main body member 51 and the point that both the first sealing material 52 and the second sealing material 53 are formed of a water-swellable non-woven fabric are the same as in the first embodiment. However, the position where the first sealing material 52 is disposed is different. That is, the pipe joint main body member 51 is a member formed with spiral concavo-convex ridges in which large-diameter portions 511 and small-diameter portions 512 are alternately arranged. In the present embodiment, the first seal member 52 has a small-diameter portion. Along the inner peripheral surface of the portion 512, the adhesive is integrated in a spiral. The second sealing material is bonded and integrated along the inner peripheral surface of the pipe joint body member and the inner peripheral surface of the first sealing material 52 in a substantially straight line so as to extend along the tube axis direction.

  Even in the present embodiment, a closed seal line is completed by the spiral first seal member 52 and the second seal material 53 disposed in the portion facing the outer peripheral surface of the pipe to be connected. The desired water stoppage can be obtained.

  Furthermore, according to the present embodiment, when the first sealing member 52 is bonded and integrated to the convexly raised portion (that is, the inner peripheral surface of the small diameter portion 512) when viewed from the inside of the pipe joint main body member 51. Since it is good, there exists an advantage that it becomes easy to perform the operation | work which adhere | attaches and integrates a 1st sealing material later on the internal peripheral surface of the pipe joint main body member shape | molded previously. Therefore, this embodiment (and the fourth embodiment) is an embodiment particularly suitable for adopting a manufacturing method in which the first sealing material is bonded and integrated manually. In addition, in these embodiments, there is also an advantage that it is easy to mechanize the work of subsequently bonding and integrating the first seal material in a spiral shape on the inner peripheral surface of a pipe joint body member that has been molded in advance. .

  6 shows a form in which the second sealing material 53 is bonded after the first sealing material 52. More preferably, in the manufacture of the pipe joint 5 of the fifth embodiment, the second sealing material 53 is the second one. The sealing material 53 is preferably bonded along the inner peripheral surface of the pipe joint body member 51 in advance of the first sealing material, and in that case, the second sealing material is bonded to the surface to be bonded. Since the second sealing material 53 can be bonded with relatively little unevenness, the second sealing material can be easily bonded.

  FIG. 7 shows a pipe joint 6 according to a sixth embodiment of the present invention. In the present embodiment, the configuration of the pipe joint main body member 61 and the configuration and arrangement of the second seal material 63 are the same as those in the first embodiment, but the structure in which the first seal material 62 is laminated. It is a seal material. That is, the first sealing material 62 is a sealing material in which a water-absorbing / expanding layer 621 made of a tape-like water-absorbing / expanding nonwoven fabric and a tape-like thin water-permeable sheet material (for example, spunbond nonwoven fabric) are laminated as a water-permeable constraining layer 622. is there. The water-absorbing expansion layer 621 is spirally bonded and integrated to the inner peripheral surface of the pipe joint main body member, and the water-permeable constraining layer 622 is provided so as to cover the water-absorption expansion layer 621 and both side edges thereof are pipe fitting main bodies. It is bonded and integrated with the inner peripheral surface of the member 61. The pipe joint as in the present embodiment sequentially supplies the tape-shaped material constituting the water-absorbing expansion layer 621 and the tape-shaped material constituting the water-permeable constraining layer 622 to the pipe-forming shaft in the spiral molding shown in FIG. Therefore, it can manufacture efficiently.

  In the present embodiment, since the water-permeable constraining layer 622 is provided so as to cover the water-absorbing / expanding layer 621, even if the water-absorbing expandable resin contained in the water-absorbing / expanding layer 621 expands, Since the water-absorbing and expanding layer 621 is prevented from being inadvertently diffused, the reliability of water-stopping can be improved even when the amount of the water-absorbing and expanding material is reduced. In addition, since it may become a channel | path which leaks if the water-permeable constrained layer 622 is thick, it is preferable to select the thin water-permeable sheet material which comprises the water-permeable constrained layer 622.

  FIG. 8 shows a pipe joint 7 according to a seventh embodiment of the present invention. In the present embodiment, the inner circumferential surface of the pipe joint body member 71 is provided with a spiral concave groove in which the first sealing material 72 is to be accommodated, and the first sealing material 72 is formed of the concave groove. It is glued and integrated in a spiral. Furthermore, in the present embodiment, the concave portion is formed so that the inner peripheral surface of the first seal member 72 does not form a step with the inner peripheral surface 71a of the pipe joint body member 71 where the first seal member 72 is not disposed. The depth of the groove and the thickness of the first seal material are determined. The main body member 71 as in the present embodiment can be manufactured by injection molding, or in the case of manufacturing by so-called spiral molding, a semi-molten resin strip is formed so as to have a concave groove on the inner peripheral side. It can be manufactured by extrusion.

According to the present embodiment, the first sealing material and the inner peripheral surface of the main body member do not cause a step, so that the gap between the outer peripheral surface of the pipe and the inner peripheral surface of the main body member or the first sealing material is reduced. Even if the clearance of the pipe is reduced, the connection operation of the pipe connection is less likely to be hindered, so the clearance between the pipe and the pipe joint can be reduced. And if a clearance can be made small, it is advantageous at points, such as a water stop and the connection strength of a pipe joint. Further, when a water-swellable material that is relatively poor in elasticity is used for the first seal material, this embodiment can be effectively employed.
Further, in the present embodiment, since the first sealing material and the inner peripheral surface of the main body member are configured so as not to cause a step, the second sealing material 73 can be easily attached and the pipe joint is efficiently manufactured. be able to.

  In the above-described embodiment, the pipe joint in which the second sealing material is disposed at one place in the circumferential direction has been described. However, the second sealing material is disposed at two places or more in the circumferential direction. May be. If the second sealing material is disposed at two or more locations, the reliability of the seal can be further increased.

  Further, in the above-described embodiment, the example in which the first seal material is provided over the entire inner peripheral surface of the pipe joint is shown. However, the pipe joint is provided in at least a part of the region facing the outer peripheral surface of the pipe to be connected. It is obvious that the sealing material may be arranged so that the space between the pipe and the pipe can be sealed. For example, the first sealing material and the second sealing material are arranged at both ends of the pipe joint, respectively, You may make it not arrange | position a sealing material in a part. Further, in the present invention, it is not always necessary to seal the both sides of the pipe joint using a water-swellable material, and only one side of the pipe joint is configured to use the water-swellable material, and the other has a different connection structure and seal. A structure may be adopted.

  According to the present invention, there is provided a pipe joint that has a sufficient water-stopping property and can prevent the water-swellable material from protruding into the pipe or crush the end of the pipe even during long-term use, and is easy to manufacture. it can. Moreover, according to the pipe joint manufacturing method of this invention, such a pipe joint can be manufactured efficiently. The obtained pipe joint can be preferably used, for example, as a pipe joint of a pipe that requires water-stopping, such as a buried underground pipe, and has high industrial utility value.

DESCRIPTION OF SYMBOLS 1 Pipe joint 11 Pipe joint main body member 111 Large diameter part 112 Small diameter part 12 1st sealing material 13 2nd sealing material 21 Pipe forming shaft 2, 3, 4, 5 Pipe coupling 21, 31, 41, 51 Pipe coupling main body member 22 , 32, 42, 52 First sealing material 23, 33, 43, 53 Second sealing material

Claims (7)

A pipe joint in which a sealing material is integrated so as to face the outer peripheral surface of the pipe to be connected to the inner peripheral surface of the substantially cylindrical pipe joint main body member,
The sealing material is composed of a first sealing material disposed in a spiral shape having a predetermined interval and a second sealing material disposed across adjacent portions of the first sealing material,
At least one of a 1st sealing material and a 2nd sealing material is a sealing material which consists of a water absorptive expansible material, The pipe joint characterized by the above-mentioned.   2. The pipe joint according to claim 1, wherein the second seal material is disposed substantially in the tube axis direction so as to cross the entire inner peripheral surface of the main body member on which the first seal material is disposed.   2. The pipe joint according to claim 1, further comprising a corrugated portion for connecting a corrugated pipe having a spiral rugged strip, wherein the first sealing material is an inner diameter of the corrugated part of the pipe joint body member. A pipe joint arranged along a peripheral surface.   2. The pipe joint according to claim 1, further comprising a corrugated portion for connecting a corrugated pipe having a spiral ridge, wherein the first seal material is an inner circumference of a small diameter portion of the corrugated part of the pipe joint body member. A pipe joint arranged along a surface.   The first sealing material is disposed so that the inner circumferential surface of the first sealing material does not form a step with the inner circumferential surface of the portion of the pipe joint body member where the first sealing material is not disposed. The pipe joint according to claim 1, wherein the pipe joint is characterized.   The pipe joint according to any one of claims 1 to 5, wherein the water-absorbable expandable material is a water-absorbable expandable nonwoven fabric. The tape-shaped material to be the first seal material and the synthetic resin strip to be the pipe joint body member are supplied to the tube forming shaft, and the first seal material is arranged and integrated on the inner periphery of the pipe joint body. A spiral molding process for molding a pipe joint member of indefinite length,
Cutting the pipe joint member obtained in the spiral molding process into a predetermined length, and making it a standard pipe joint;
The method for producing a pipe joint according to claim 1 by a second seal material integration step in which a tape-like second seal material is disposed and integrated on an inner peripheral surface of a fixed-size pipe joint obtained in the cutting step.

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