JP6812302B2 - Seal structure - Google Patents

Description

The present invention relates to a seal structure that seals between an outer pipe and an inner pipe inserted inside the outer pipe, particularly a seal structure using a water-absorbing and expandable material.

A seal structure is adopted as necessary for the part connecting the pipes. For example, an underground pipe used for inserting an electric cable, a communication cable, or the like is provided with a waterproof seal structure at a connection portion such as a pipe joint so that water does not enter the pipe.

As a seal structure for stopping water at a connection portion of an underground pipe or the like, a seal member using a water-absorbing and expandable material is known.
As a sealing member using a water-absorbent expandable material, a seal member using a water-absorbent expandable non-woven fabric is known. For example, Patent Document 1 describes that a sheet having a two-layer structure including a water-expandable non-woven fabric is formed into a cylindrical shape to form a sealing member. Then, the pipe joint with a seal member in which the seal member is welded to the pipe joint and integrated is described. Such a pipe joint with a seal member is convenient because the seal structure is completed only by screwing and connecting the pipe joint and the pipe.

As an example of using other water-absorbent and expandable materials, Patent Document 2 describes a seal structure in which water-swellable rubber is used as a part of the seal member. Patent Document 2 discloses that a long strip whose both ends (ball edges) and the like are made of water-swellable rubber is used as a sealing member, and this is provided along the spiral unevenness of the corrugated tube.

JP-A-2004-336953 Japanese Patent Application Laid-Open No. 2-245594

Since the sealing member of Patent Document 1 uses an end-shaped water-absorbing and expandable non-woven fabric sheet in a cylindrical shape, it has butt portions at both ends of the non-woven fabric. In such a butt portion, a gap is likely to occur, and so-called water running causes poor water stoppage.

Further, if there is a gap in the seal structure including the abutting portion, the water-stopping property deteriorates. Therefore, it is required that the water-absorbing and expandable material be integrated with the constituent member such as a pipe joint without a gap. On the other hand, due to demands such as cost, it is required to efficiently integrate the water-absorbent and expandable material with the constituent members of the seal structure. However, in the conventional seal structure such as the pipe joint with a seal member of Patent Document 1, the work of integrating without a gap in this way requires a great deal of labor. In particular, when the pipe or the joint is a pipe with a spiral wave, it is difficult to integrate the seal member without a gap while adapting it to the unevenness of the pipe wall. In some cases, as shown in Patent Document 1, a special process such as injection integral molding may be required.

An object of the present invention is to provide a sealing structure in which water running is less likely to occur and a sealing member made of a water-absorbing and expandable material can be easily integrated into a pipe or a pipe joint body.

As a result of diligent studies, the inventor has found that the above problems can be solved by forming two rows of sealing members made of a water-absorbing and expandable material and arranging the sealing members with their butt lines shifted. , The present invention has been completed.

The present invention is a first seal structure that seals between the outer pipe and the inner pipe inserted inside the outer pipe, and is sandwiched between the outer pipe and the inner pipe and adjacent to the pipe axis direction. A set of a seal member including a seal member and a second seal member is included, and the first seal member and the second seal member are integrated with the inner peripheral surface of the outer pipe or the outer peripheral surface of the inner pipe, and the first seal member and the second seal member are integrated. Each of the seal members is made of a strip made of a water-absorbing and expandable material, and has a ring shape in which both ends of the strip are butted against each other, and the end point of the butting line of the first seal member and the second seal member side. This is a seal structure in which the end point on the side of the first seal member of the butt line of the second seal member is offset in the circumferential direction of the pipe (first invention).

In the first invention, the end point on the side of the second seal member in the butt line of the first seal member and the end point on the side of the first seal member in the butt line of the second seal member are offset by 45 ° or more around the central axis of the pipe. (2nd invention).
In the first invention, it is preferable that the butt line of the first seal member is inclined with respect to the longitudinal direction of the strip (third invention). It is preferable that the butt line of the first seal member has a stepped shape (fourth invention).

According to the seal structure (first invention) of the present invention, it is easy to integrate a seal member made of a water-absorbing and expandable material into a pipe or a pipe joint body, and water running can be suppressed.

Further, as in the second invention, if the offset is secured at a certain level or more, the effect of suppressing water running is high. Further, if the butt line is designed as in the third invention and the fourth invention, the effect of suppressing water running can be further enhanced.

It is a front view and sectional view which shows the pipe joint which concerns on the seal structure of 1st Embodiment. It is a partial cross-sectional view which shows the example which is the seal structure of 1st Embodiment, and has applied the seal structure to the connection part of a pipe joint and a pipe. It is a front view which shows the process of connecting a pipe joint which concerns on a seal structure of FIG. 2 and two pipes. It is a front view which shows the strip made of the water absorption expansion material which concerns on the seal member of 1st Embodiment. It is a front view which shows the other example of the strip made of the water absorption expansion material. Another example of the seal structure is a partial cross-sectional view showing an example in which the seal structure is applied to a connection portion where a pipe is connected to a hole provided in a wall surface.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, exemplifying an embodiment in which the present seal structure is applied to a connection portion between a pipe joint and a pipe with a spiral wave. The invention is not limited to the individual embodiments shown below, and the embodiments can be modified and implemented.

1 to 4 show a specific configuration according to the first embodiment of the present invention. FIG. 1 is a front view and a cross-sectional view showing a pipe joint related to a seal structure, FIG. 2 is a partial cross-sectional view showing a state in which the pipe joint and the pipe are connected, and FIG. 3 is a pipe joint and a pipe. FIG. 4 is a front view showing a process of connecting the above, and FIG. 4 is a front view showing a strip made of a water-absorbing and expandable material serving as a sealing member.

The pipe joint 1 shown in FIG. 1 has spiral irregularities on the inner peripheral surface, and as shown in FIG. 3, the pipes 3a and 3b with spiral waves can be screwed from both ends to connect the pipes with spiral waves. It has become. The state in which the connection is completed is shown in FIG.
The pipe joint 1 is composed of a joint body 11 and a set of sealing members integrated at both ends thereof. Each set of seal members includes a first seal member 21 and a second seal member 22. The first seal member 21 and the second seal member 22 are arranged so as to be adjacent to each other in the pipe axis direction to form a set of seal members.

In the present invention, of the set of seal members, the one near the outside of the pipe at the pipe connection portion is referred to as the first seal member, and the one far from the outside of the pipe is referred to as the second seal member. In the present embodiment, the one outside the end of the pipe joint 1 is the first seal member 21, and the one inside the end is the second seal member 22.

The state in which the connection is completed will be described by taking the X-end side of the pipe joint 1 in FIG. 2 as an example. When the connection is completed, the joint body 11 and the spiral wave tube 3a are sealed by a set of sealing members. That is, a set of sealing members 21 sandwiched between the joint body 11 as the "outer pipe" and the spiral wave-bearing pipe 3a as the "inner pipe" inserted and arranged inside the joint body 11. , 22 completes the seal structure.

Similarly, the Y-end side is also sandwiched between the joint body 11 as the "outer pipe" and the spiral waved pipe 3b as the "inner pipe" inserted and arranged inside the joint body 11. This means that the seal structure consisting of a set of seal members has been completed.

When water infiltrates the completed seal structure portion from the outside of the pipe connection portion, the water first reaches the first seal member 21, and when it permeates through the first seal member 21, it then reaches the second seal member 22. Reach sequentially. The sealing structure exhibits excellent sealing performance by having such a two-stage sealing mechanism.

Known joint bodies 11 and spiral wave tubes 3a and 3b can be used. For example, it is molded from a synthetic resin, preferably a polyolefin resin or a polyvinyl chloride resin, by a known molding method such as injection molding or blow molding.

Hereinafter, aspects of the set of seal members 21 and 22 will be specifically described.
The first seal member 21 and the second seal member 22 each form a ring shape and are sandwiched between the outer pipe and the inner pipe to form an independent closed seal line.

Here, each ring-shaped sealing member is formed by abutting both ends of a strip made of a water-absorbing and expandable material. Therefore, each seal member has a butt line formed by the butt ends of the seal member. The first seal member 21 has a butt line 21a, and the second seal member 22 has a butt line 22a, respectively. In the second seal member on the X-end side of FIG. 2, the butt line 22a is not shown originally because it is on the front side of the cross section, but it is shown as a broken line to indicate the position in the circumferential direction in the pipe.

The seal member 21 and the seal member 22 form a set of seal members adjacent to each other in the pipe axis direction, but at that time, the butt lines are not continuous but are divided and arranged at different positions in the circumferential direction. It is configured to be. In order to establish such a positional relationship between the butt lines, the second seal member side end point 21b in the butt line of the first seal member and the first seal member side end point 22b in the butt line of the second seal member May be configured to be offset in the circumferential direction of the tube. Here, in order to prevent each butt line from becoming a continuous line as much as possible, the line end points of the butt line are separated from each other in the circumferential direction, and the other butt line is on the extension line of one butt line. It is desirable that they do not overlap.

Specific positioning by offsetting the end points 21b and the end points 22b may be performed as follows, for example. When each seal member is considered as a ring that can rotate around the central axis, the offset position can be set to the position where the rings are rotated relative to each other and rotated until the end points are appropriately separated from each other. In the present invention, the case where the end points are in the positional relationship determined in this way is regarded as a state of being offset in the circumferential direction.

When positioning the end points of each other in the actual seal structure, the offset amount may be defined by the angle around the central axis of the pipe with the central axis of the pipe as a reference point for convenience. In this case, the offset is preferably 45 ° or more around the central axis of the pipe, and more preferably 60 ° or more around the central axis.

Further, the offset amount between the end points may be specified based on the distance between the end points. In this case, it is preferable that the shortest distance between the end points in the circumferential direction is at least the band width of the first seal member or more, and the distance is 1.5 to 4.0 times the strip width. Is more preferable.

A more detailed example of the offset will be described in this embodiment. Here, for convenience, the description will be made with reference to the cross-sectional view of FIG. Further, in FIG. 2, the seal structure realized on the X end side of the pipe joint 1 is referred to as a first seal structure, and the seal structure realized on the Y end side is referred to as a second seal structure.

First, in the first seal structure, the end points 21b and the end points 22b are displaced by about 180 ° around the central axis of the pipe. That is, it can be said that the end points 21b and the end points 22b are offset by 180 ° around the central axis of the pipe. As described above, in the first seal structure, the distance between the end points 21b and 22b is offset to the maximum.
Next, in the second seal structure, the end points 21b and the end points 22b are displaced by about 90 degrees in the circumferential direction of the pipe. That is, in the second seal structure, it can be said that the end points 21b and the end points 22b are offset by 90 °.

With this configuration, the butt lines 21a and 22a are separated, and the flow path of water running in the set of sealing members is also divided.

Next, a method of producing the seal members 21 and 22 will be described.
Each sealing member is made of a strip made of a water-absorbing and expandable material as shown in FIGS. 4 and 5.
The length of the strip made of the water-absorbing and expandable material may be set according to the mode of the butt portion of the sealing member so as not to create a gap in the butt portion as much as possible. For example, it is preferable that the length substantially matches the peripheral length of the peripheral surface of the pipe on which the seal member is arranged.

The water-absorbing and expanding material is not particularly limited as long as it is a material that absorbs moisture and expands and exhibits sealing properties, and the water-absorbing and expanding material should be a known material having elasticity and cushioning properties. Can be done. For example, water-absorbent rubber, water-absorbent resin, water-absorbent expandable non-woven fabric and the like can be mentioned. Further, a water-absorbent expandable non-woven fabric is preferable from the viewpoint of having flexibility and elasticity that can be easily integrated along the inner peripheral surface of the pipe joint 1.

The strip 2a made of the water-absorbing and expanding material may include a material other than the water-absorbing and expanding material. For example, a strip having a base material that improves the fixing property and strength to the pipe wall may be integrated with the water-absorbing and expanding material. Examples of the base material include an adhesive sheet and the like.

The width of the strip, that is, the width of the sealing member may be appropriately set so as to ensure the sealing property, but can be, for example, 1 cm or more and 4 cm or less. When the seal member is fixed to the spiral uneven wavy surface as in the pipe joint 1 according to the present embodiment, the width of the seal member is preferably 0.5 to 3 times the spiral pitch, and is 0.8 to 0.8. Twice is more preferable, and it is preferable that it is substantially equal to the spiral pitch.

The widths of the first seal member and the second seal member may be different, but are preferably substantially the same. With this design, the flow path of the water run in the set of seal members is divided at the center in the pipe axis direction, so that the effect of suppressing the water run is maximized.

The first seal member 21 and the second seal member 22 are formed by abutting both ends of the strip 2a made of a water-absorbing and expandable material in a ring shape.
It is preferable that there is substantially no gap between the abutting portions at both ends of the seal member from the viewpoint of water stopping, but a certain gap may be provided from the viewpoint of workability. When there is a gap, for example, the gap is preferably 3 mm or less, and more preferably 1 mm or less. When there is a gap in the butt portion of the seal member, the butt line has a constant width corresponding to the gap.

On the other hand, at the butt portion, one end of the strip 2a made of the water-absorbing and expandable material may ride on the other end side. In this case, in the butt portion, there is an end portion on the riding side and an end portion on the underlay side. Here, each of the end on the riding side and the end on the underlay side may be treated as a butt line. For example, at the end of the underlay side, a gap may be formed between the end of the underlay side, the riding portion of the strip 2a, and the pipe wall of the outer pipe. Similarly, at the end on the riding side, a gap may be formed between the end on the riding side, the underlay portion of the strip 2a, and the pipe wall of the inner pipe. These gaps can be a butt line that makes it easy for water to run.

In the embodiments shown in FIGS. 1 to 4, an example is shown in which the butt line is a straight line inclined in the longitudinal direction of the strip. However, the butt line of each seal member is not limited to this. For example, the orientation of the butt line may be perpendicular to the longitudinal direction of the strip or may be inclined. The shape of the butt line may be a straight line, but may be a bent line, a zigzag line, or a curved line. For example, when the strip 2b shown in FIG. 5 is used, the butt line is a straight line perpendicular to the longitudinal direction of the strip.

As will be described later, from the viewpoint of effectively suppressing water running, it is preferable to lengthen the butt line. In order to lengthen the butt line, for example, by using the strip 2a shown in FIG. 4, the butt line can be inclined with respect to the longitudinal direction of the strip and the central axis direction of the pipe joint as in the present embodiment. preferable. Alternatively, it is also preferable to use the strips 2c and 2d shown in FIG. 5 to bend the butt line into a key shape, that is, an uneven shape or a stepped shape.

It should be noted that the shape of such a butt line does not necessarily have to be applied to both of a set of sealing members, and even if it is applied to only one of the first sealing member or the second sealing member, the effect of suppressing water running is effective. Is enhanced. Therefore, in one set of seal members, the shape of the butt line of each seal member may be the same or different.

The two seal members formed in this way are arranged so as to be adjacent to each other in the pipe axis direction to form a set of seal members. From the viewpoint of water stopping, it is preferable that these sets of sealing members are adjacent to each other with substantially no gap, but from the viewpoint of workability, they may be adjacent to each other with a certain gap. When there is a gap, the width of the gap is preferably not more than or equal to the width of the strip of the first sealing member 21, preferably not more than 0.3 times the width of the strip, and not more than 0.1 times. It is more preferable to have. Alternatively, the width of the gap is preferably 3 mm or less, and more preferably 1 mm or less.
If the adjacent distance of a set of sealing members is not constant in the circumferential direction of the pipe, the longest distance between the sealing members may be treated as the adjacent distance.

On the other hand, the set of seal members may be arranged adjacent to each other so that a part of one seal member rides on the other seal member.

Next, it will be described that the seal structure of the present embodiment is completed by the pipe connection operation.
As described above, the pipe joint 1 is provided with a set of sealing members at both ends in advance. Therefore, if the pipe is screwed into the pipe joint and the connection work is completed as in the usual method, the seal structure of the present embodiment is completed as it is at both ends without requiring any special work. Therefore, if the pipe joint 1 is used, the seal structure of the present embodiment can be easily provided at a place where the pipe body is connected by the pipe joint.

Then, in the seal structure of the present embodiment, when water infiltrates from the connection portion of the pipe, the seal member absorbs water and expands, and the minute gap in the seal structure is closed to complete the seal. To do.

Next, a method of manufacturing the pipe joint 1 will be described. The pipe joint 1 can be manufactured by, for example, the following method.
First, the joint body 11 and four strips 2a made of the water-absorbing and expandable material shown in FIG. 4 are prepared. Next, the two strips 2a are fixed to the inner peripheral surface of the pipe wall on the X-end side of the joint body 11 so that both ends of the strips 2a are butted against each other to form a ring shape. In this way, the seal members 21 and 22 according to the first seal structure can be formed. Similarly, if the seal members 21 and 22 according to the second seal structure are formed on the Y-end side by the remaining two strips 2a, the pipe joint 1 is completed.

The method of fixing the strip is not particularly limited as long as it can obtain a close contact state with substantially no gap between the strip 2a and the inner peripheral surface of the pipe wall of the joint body 1. Examples include adhesion, adhesion, hot melt and fusion. As the fixing means, a chemical such as an adhesive or an adhesive, double-sided tape or the like may be used. The fixing work may be performed by the operator's hand (hand-pasting) or by mechanical means such as a roller or a jig, and each means may be used in combination. The fixing work is preferably performed in a dry environment so that the seal member does not absorb and expand water and impair workability when connecting the pipe.

For example, when the fixing work is performed by hand pasting, first, the strip 2a is brought into close contact with the joint body 11 in a ring shape by using an adhesive or the like so as to be along the inner peripheral surface of the pipe wall. At this time, care should be taken not to create a gap while blending the strip 2a into the spiral unevenness. Next, the first seal member 21 is formed by abutting both ends of the strip 2a so that a butt line with as little gap as possible is formed.

The second seal member 22 is created by the same procedure as described above, except that the butt lines are positioned in advance so as to be offset in the pipe circumferential direction prior to the work of adhering to the inner peripheral surface of the pipe wall. do it.
The order in which the first seal member 21 and the second seal member 22 are produced is not particularly limited, and the order may be determined from the viewpoint of workability.

As another manufacturing method of the pipe joint 1, it can also be manufactured by using injection molding. In this case, the seal member is temporarily fixed at a predetermined position on the core mold capable of forming the inner peripheral surface of the joint body 11. A cavity mold that can form the outer peripheral surface of the joint body 11 is molded to form a cavity so as to surround the core mold in this state, and a molten resin is injected into the cavity to form the joint body. The member can be integrated with the joint body 11.

In the present embodiment, an example is shown in which the first seal member 21 and the second seal member 22 are arranged in advance as a set of seal members on the side of the joint body 11. As described above, it is preferable that the individual sealing members according to the present invention form a set of sealing members in advance before the pipes are connected. That is, it is preferable that the inner peripheral surface of one outer pipe or the outer peripheral surface of one inner pipe constituting the pipe connecting portion is integrated as a set of sealing members. If a set of sealing members is configured before connecting the pipes, the offset between the end points can be easily and surely adjusted, and the effect of suppressing water running can be easily enhanced.

However, the first seal member and the second seal member before the connection of the pipes do not necessarily have to be integrated into the same pipe body. That is, the second seal member may be integrated with the inner peripheral surface of the outer pipe constituting the connecting portion, and the first seal member may be integrated with the outer peripheral surface of the inner pipe inserted inside the outer pipe.

Further, as long as a set of sealing members is formed after the pipes are connected, it is particularly important whether the first sealing member or the second sealing member is integrated with the outer pipe or the inner pipe before the pipes are connected. It is not limited as long as it is integrated with the inner peripheral surface of the outer pipe or the outer peripheral surface of the inner pipe constituting the connecting portion.

For example, in the joint body 11 according to the present embodiment, for the set of seal members 21 and 22 arranged on the X end side, the seal member 21 is integrated with the spiral wave tube 3a side, and the seal member 22 is the joint body. It may be integrated with 11, or both may be on the side of the spiral wave tube 3a.

The operation and effect of the seal structure of the present embodiment will be described.
According to the seal structure of the present embodiment, it is possible to suppress poor water stoppage at the seal portion, particularly water running.

As a result of investigating the improvement of water-stopping property of the seal structure using the water-absorbent and expandable material, the inventors of the conventional seal structure absorb water and expand the seal member, especially at the seam portion and the butt portion of the seal, and the seal is formed. It was found that water running was likely to occur by the time it was completed.

The seal member using the water-absorbing and expanding material shifts from a dry state in which it does not absorb water to a saturated state in which water-absorbing expansion is completed through an expansion process in which water is absorbed and expansion is progressing. Normally, the water-absorbing and expandable sealing member is not yet completely sealed in the expansion process, and is completely sealed in the saturated state.

Here, a phenomenon in which water permeates through a gap such as a seam of a seal during the expansion process is water running. In particular, the seal member using the water-absorbing and expandable material tends to have a gap at the butt portion of the strip end portion and the like, and tends to cause water running along the butt line.

On the other hand, as shown in FIGS. 1 and 2, the seal structure of the present embodiment includes a set of seal members composed of a first seal member and a second seal member adjacent to each other in the pipe axis direction, and the first seal. Each of the member and the second seal member is made of a strip made of a water-absorbing and expandable material, and has a ring shape in which both ends of the strip are butted against each other, and the second seal of the butting line of the first seal member is formed. The end point on the member side and the end point on the first seal member side of the butt line of the second seal member are offset in the circumferential direction of the pipe.

That is, the flow path of the water running along the butt line in this seal structure is divided without penetrating in the axial direction of the pipe. Therefore, even if water runs on the seal line formed by the first seal member 21, the tip of the water run flow path abuts on the side end of the second seal member 22, so that the water that runs on the water finally becomes the first. 2 Water is reliably absorbed by the seal member 22.
Due to the above action, in the seal structure of the present embodiment, even if water runs along the butt line on the first seal 21, it is possible to prevent the infiltrated water from reaching the inside of the inner pipe.

In particular, when the butt line of the first seal member 21 is inclined with respect to the longitudinal direction of the strip and the central axis direction of the tubular body as in the above embodiment, the infiltrated water is along the butt line. The flow path for running water becomes longer. As a result, the possibility that the water that has entered the butt line before the first seal member 21 reaches the saturation state permeates the seal member is reduced, and the effect of suppressing water running is further enhanced.

Further, according to the seal structure of the present embodiment, the work of integrating the seal member into the joint body can be facilitated.
The conventional seal structure using the water-absorbing and expanding material has a problem that a large amount of labor is required for fixing the strip made of the water-absorbing and expanding material to the pipe wall or the like. In particular, when the sealing member is arranged along the inner peripheral surface of the spiral wave tube as in the present embodiment, it is necessary to fix the strip made of the water-absorbing and expandable material while blending it with the uneven surface. .. Such work requires a great deal of labor because it requires carefulness and skill of the worker.
Further, depending on the shape and size of the water-absorbing and expandable material, the follow-up to the uneven surface of the inner peripheral surface of the pipe wall may be insufficient, and a gap may be formed between the seal member and the joint body.

On the other hand, the seal structure of the present embodiment has a structure as long as the two seal members can exhibit the sealing property as a set. Therefore, the width of each seal member can be halved from the width required in the conventional seal structure. When the width of the strip is halved, it becomes very easy to fix it on the uneven surface.

The invention is not limited to the above embodiment, and can be implemented with various modifications. Other embodiments of the invention will be described below, but in the following description, parts different from the above-described embodiments will be mainly described, and detailed description of similar parts will be omitted. In addition, these embodiments can be implemented by combining some of them with each other or replacing some of them.

FIG. 6 is an example of another embodiment of the seal structure of the present invention, and is a partial cross-sectional view showing an example in which the seal structure is applied to a connection portion where a pipe is connected to a hole provided in a wall surface. Such a connection structure can be applied to a place where the underground pipe is connected to a hand hole or the like.

In the present embodiment, the spiral corrugated pipe 3 inserted through the pipe through hole 8b has a wall portion 8 sandwiched between the flange member 41 and the bell mouth 5 by screwing and tightening the tightening member 42. It is fixed.

A tightening member 42 is screwed into the spiral wave tube 3 via a first tubular portion 42a. The tightening member 42 is composed of a first tubular portion 42a, a step portion 42b, and a second tubular portion 42c. The first tubular portion 42a is formed in a spiral wave tube 3 that can be screwed into the spiral wave tube 3. The second tubular portion 42c is formed in a straight tubular shape.

The flange member 41 is composed of a tubular portion 41a and a flange portion 41b. The tubular portion 41a is formed in a straight tubular shape. Here, the second tubular portion 42c of the tightening member 42 is fitted to the tubular portion 41a.

The flange member 41 is integrated with the tightening member 42 to fix the spiral wave tube 3 to the wall portion 8. The tubular portion 41a is inserted into the second tubular portion 42c and is further abutted against the stepped portion 42b to complete the fitting with the tightening member 42. Then, when the tightening member 42 is screwed into the spiral wave tube 3 and tightened, the flange portion 41b is pressed against the wall surface 8a, and the spiral wave tube 3 is fixed to the wall surface 8a.

A known seal structure using a known seal member 43 is provided between the flange portion 41b and the wall surface 8a independently of the seal structure of the present invention.

A bell mouth 5 is screwed and attached to the inside of the tip of the spiral wave tube 3. The bell mouth 5 has a cylindrical main body 51 whose outer shape is formed to be slightly smaller than the inner diameter of the spiral wave tube 3 to be screwed, and the outer peripheral surface of the main body 51 has a spiral wave tube. The convex portion 51b, which becomes a screw thread at the time of screwing, is formed in a spiral shape. With this configuration, the bell mouth 5 is screwed into the spiral wave tube 3 and can be fixed to the wall surface 8a. However, the configuration of the bell mouth is not limited to this, and other known configurations may be used.

As the tightening member 42, the flange member 41 and the bell mouth 5, known ones can be used. For example, it is molded from a synthetic resin, preferably a polyolefin resin or a polyvinyl chloride resin, by a known molding method such as injection molding or blow molding.

In the present embodiment, the space between the first tubular portion 42a of the tightening member 42 and the spiral corrugated pipe 3 is sealed by the sealing members 63 and 64. The first seal structure and the second seal structure shown in FIGS. 1, 2 and the like in the first embodiment can be applied to such a portion. In this case, the first tubular portion 42a corresponds to the "outer tube", and the spiral wave tube 3 corresponds to the "inner tube".

As described above, the application target of the seal structure as shown in FIGS. 1 and 2 is not limited to the pipe and the pipe joint, but is applied to the seal between the pipe and the tightening member, or between the pipe and another pipe or the like. it can.

Further, in the present embodiment, the tubular portion 41a of the flange member 41 and the second tubular portion 42c of the tightening member 42 are sealed by the sealing members 61 and 62. The first seal structure and the second seal structure shown in FIGS. 1, 2 and the like in the first embodiment can be applied to such a portion. In this case, the tubular portion 41a corresponds to the "inner tube" and the second tubular portion 42c corresponds to the "outer tube".

As described above, the application target of the seal structure illustrated in FIGS. 1 and 2 is not limited to the uneven corrugated pipe, and can be applied as a structure for sealing between straight pipes as in this example.

Further, when the outer pipe and the inner pipe constituting the pipe connection portion are connected at the tip of each other in this way, the seal position of the outer pipe and the inner pipe is clearly determined even before the pipe is connected. , It is preferable that a set of sealing members is integrated with the outer peripheral surface of the inner pipe in advance. When the sealing member is integrated with the outer peripheral surface of the inner pipe, the work is easier than integrating with the inner peripheral surface of the outer pipe, so that more reliable sealing performance can be easily obtained.

According to this seal structure, water running can be suppressed in any of the above embodiments, and the work of integrating the seal members is easy.

The seal structure of the present invention can also be used in combination with other seal structures. For example, when there are two parts to be sealed in the pipe connection structure, both parts may be sealed by the sealing structure of the present invention as shown in the embodiments of FIGS. 1 and 2, and one part may be sealed by the present invention. While using the seal structure of the present invention, a conventional seal structure may be used in other places.

The seal structure of the present invention may include a set of seal members composed of a first seal member and a second seal member, as well as other seal members. For example, a third seal member having substantially the same configuration as the first seal member or the second seal member may be provided adjacent to the set of seal members.
In this case, it is preferable that the end points of the third seal member and the end points of the adjacent seal members are offset in the circumferential direction. The mode of offset is as described in the first embodiment.

Regarding the pipe connecting portion to which the seal structure of the present invention is applied, the outer pipe and the inner pipe constituting the pipe connecting portion are not limited to long pipes, and for example, the tightening member 42 of the embodiment of FIG. Like the seal structure between the flange member 41 and the flange member 41, it may be a pipe connection portion between short pipes. Here, the short pipe means a pipe whose length is about three times or less the diameter of the pipe.

The seal structure of the present invention can be applied to other technical fields other than those exemplified in the above embodiments.

The seal structure of the present invention can be used in a connection structure such as an underground pipe, and can improve the water blocking property and the seal workability of the seal portion, and has high industrial utility value.

1 Pipe fitting 11 Joint body 21 First sealing member 21a, 22a Butting line 21b, 22b End point 22 Second sealing member 3 Spiral wave pipe 41 Flange member 41a Tubular part 41b Flange part 42 Tightening member 42a First tubular part 42b Step 42c Second tubular part 5 Bellmouth 51 Main body 51b Convex 61, 64 First sealing member 62, 63 Second sealing member 8 Wall 8a Wall 8b Through hole for piping

Claims (4)

It is a sealing structure that seals between the outer pipe and the inner pipe inserted inside the outer pipe.
A set of a seal member composed of a first seal member and a second seal member adjacent to each other in the pipe axis direction sandwiched between the outer pipe and the inner pipe is included, and the first seal member and the second seal member are the inner circumference of the outer pipe. It is integrated with the surface or the outer peripheral surface of the inner pipe,
The first seal member and the second seal member are each made of a strip made of a water-absorbing and expandable material, and have a ring shape in which both ends of the strip are butted against each other.
A seal structure in which the end point on the side of the second seal member of the butt line of the first seal member and the end point on the side of the first seal member of the butt line of the second seal member are offset in the circumferential direction of the pipe. The first aspect of claim 1, wherein the end point on the side of the second seal member in the butt line of the first seal member and the end point on the side of the first seal member in the butt line of the second seal member are offset by 45 ° or more around the central axis of the pipe. Seal structure. The seal structure according to claim 1 or 2, wherein the butt line of the first seal member or the second seal member is inclined with respect to the longitudinal direction of the strip. The seal structure according to claim 1 or 2, wherein the butt line of the first seal member or the second seal member has an uneven shape or a stepped shape.

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